WO2012058177A1

WO2012058177A1 - Method of forming a shaped foam laminate article

Info

Publication number: WO2012058177A1
Application number: PCT/US2011/057563
Authority: WO
Inventors: Myron J. Maurer; Cindy Hanson; Matthew D. Mittag; Alain Sagnard; Piyush Soni
Original assignee: Dow Global Technologies Llc; Rohm And Haas Chemicals Llc
Priority date: 2010-10-29
Filing date: 2011-10-25
Publication date: 2012-05-03

Abstract

The present invention is a method to manufacture a shaped foam laminate article (5) comprising a foam laminate 83) with a first foam layer (15) and a second foam layer (2) and shaped foam laminate articles made therefrom. Specifically, the first foam of the first foam layer (15) having a vertical compressive balance equal to or greater than 0.40 and the second foam of the second foam layer (2) having a vertical compressive strength equal to or greater than the vertical compressive strength of the first foam layerb (15).

Description

METHOD OF FORMING A SHAPED FOAM LAMINATE ARTICLE

The present invention is a shaped foam laminate article and method for

manufacturing such an article. Specifically, the shaped foam laminate article comprises a first foam layer comprising a first foam, and a second foam layer comprising a second foam, wherein the first foam is different than the second foam and the first foam has a vertical compressive balance of at least 0.40 and the second foam has a vertical compressive strength equal to or greater than the vertical compressive strength of the first foam.

It is well known in the construction and home improvement industries to provide exterior surfaces to buildings for protective and decorative purposes. For example, these surfaces include shaped roofing materials of shingles, tiles, or metal; brick; stone; plaster; and/or siding panels of metal, plastic, or wood which can be nailed or otherwise affixed to the exterior surface of a building. While such exterior surfaces provide protection and/or a desirable appearance to building exteriors, they typically do not provide adequate insulation and so there exists the need for additional insulation.

The use of foamed plastic material for insulating purposes is well known as such foamed plastic materials have a very low thermal conductivity. Thermal conductivity is measured in BTUs per hour per cubic foot per degree Fahrenheit per inch and is often described in terms of its reciprocal, referred to as 'R-value' . Polystyrene, polyurethane, and polyisocyanurate foam offer excellent insulating efficiency (R-value) versus other insulating products. These insulation foams are typically provided in the form of a foam insulation board, extruded or expanded bead foam, measuring from 0.25 inch to 4 or more inches thick.

Attempts have been made to provide support of the exterior surface by combining the insulation with the exterior surface by forming a composite foam material, for example, see USP 4,320,613, and references therein.

USP 6,321,500 discloses a siding unit having at least two courses of vinyl siding wherein a reinforcing panel is glued or otherwise laminated to the inside of each course of vinyl siding. The reinforcing panel is preferably made of expanded or extruded polystyrene.

USP 7,040,067 discloses a siding panel with an insulated backing panel.

See USP 6,948,288 which discloses a roof tile support element constructed from a compressible material that fits between roof tiles and a roofing surface to provide support for the roof tiles, which allows individuals to walk confidently on a tile roof without breaking tiles. USP 6,516,578 discloses a brick panel system wherein "thin brick" is used in conjunction with a mono-layered shaped foam backing wherein said mono-layer shaped foam backing is molded from closed-cell expanded polystyrene bead foam. However the expanded bead foam process of this invention is costly due to (1) expensive tooling, which, among other things, requires steam lines to aid in the expansion of the impregnated blowing agent (i.e., penetrate) in the beads resulting in long cooling times prior to ejection the molded panel which translates into (2) lengthy cycle times.

USP 6,931,809 discloses a laminated wall structure comprising a layer of building sheathing adhered to one surface of a mono-layered panel of thermal insulating expanded polystyrene with a water resistant adhesive, wherein the other surface of the expanded polystyrene panel is provided a finish system, such as a base coat comprising fiberglass and a finish coat. However, USP 6,931,809 does not teach or suggest imparting shape to the laminated wall structure.

WO 2007/033255 discloses a radiant heating assembly for use as part of a laminar floor construction to provide radiant heating. Said radiant heating assembly comprises a shaped steam chest molded, thermally insulating expanded polystyrene foam panel having a groove fitted with a plate of non-thermally conductive material, which in turn

accommodates a radiant heating element. However, said shaped foam panel is a steam chest molded panel requiring costly injection and a time/energy intensive process wherein beads are disposed within a defined mold cavity, steam is introduced to the closed mold to soften the bead walls and allow the entrapped blowing agent, such as pentane, to expand and then the resulting shaped foam article must be cooled before removal from the mold.

A process by which shaped foam articles may be produced for exterior surface applications is disclosed in US Publication 2009/0062410 (65356A), specifically a process to make a shaped foam article in the shape of a shake shingle is disclosed. However, 2009/0062410 is silent as to what, if any, insulation properties the shaped foam article provides. Moreover, based on the use of C0₂ as the blowing agent and the resulting low internal cell gas pressure, the foams described therein would be expected to have an R- value of around 4 per inch or lower, which may not be sufficient to provide adequate insulation in exterior building surface applications.

It would be desirable to have a simple, cost-effective method to make a shaped foam laminate article for decorative exterior surface applications having improved insulation properties. The present invention is such a simple, cost effective method to prepare a shaped foam laminate article comprising a first foam layer and a second foam layer comprising the steps of:

(A) preparing a foam laminate by the steps comprising:

(i) preparing a first foam layer from a first foam blank by the steps comprising:

(i.a) extruding a first thermoplastic polymer composition with a blowing agent to form a first thermoplastic polymer foam plank, the first foam plank having a thickness, a top surface, and a bottom surface in which said surfaces lie in the plane defined by the direction of extrusion and the width of the first foam plank, wherein the first foam plank has a vertical compressive balance equal to or greater than 0.4 and an internal cell gas pressure less than 1 atmosphere

and

(i.b) forming a first foam blank from the first foam plank by preparing one or more pressing surface wherein the resulting first foam blank has a first pressing surface and a second surface,

(ii) preparing a second foam layer from a second foam plank by the steps comprising:

(ii.a) foaming a second polymer composition to form a second foam plank, the second foam plank having a thickness, a top surface, and a bottom surface, wherein the second foam plank has a vertical compressive strength equal to or greater than the vertical compressive strength of the first foam plank,

and

(iii) bonding the second surface of the first foam blank to a surface of the second foam plank to form a foam laminate, preferably bonding by thermal means, mechanical means, physical means, chemical means, adhesive means, or combinations thereof,

and

(B) providing shape to the first foam layer of the foam laminate by:

(i) contacting the pressing surface of the first foam layer with a mold and (ii) pressing the pressing surface of the first foam layer such that a shaped foam laminate article is formed.

In another embodiment, the present invention is a method to prepare a shaped foam laminate article comprising a first foam layer and a second foam layer comprising the steps of:

(i) preparing a first foam layer by the steps comprising:

and

(i.b) forming a first foam blank from the first foam plank by preparing one or more pressing surface wherein the resulting first foam blank has a first pressing surface and a second surface, said first foam blank is the first foam layer,

(ii.a) foaming a second polymer composition to form a second foam plank, the second foam plank having a thickness, a top surface, and a bottom surface, wherein the second foam plank has a vertical compressive strength equal to or greater than the vertical compressive strength of the first foam plank, said second foam plank is the second foam layer,

(iii) providing shape to the first foam layer by:

(iii.a) contacting the pressing surface of the first foam layer with a mold and

(iii.b) pressing the pressing surface of the first foam layer such that a shaped first foam layer is formed,

and

(iv) bonding the second surface of the shaped first foam layer to a surface of the second foam layer to form a shaped foam laminate, preferably bonding by thermal means, mechanical means, physical means, chemical means, adhesive means, or combinations thereof.

In one embodiment of the present invention, the second foam layer of the methods described herein above has an R- value per inch greater than the R- value per inch of the first foam layer.

In another embodiment of the present invention, the first foam of the methods described herein above comprises a first thermoplastic polymer and the second foam comprises a second thermoplastic polymer.

In another embodiment of the present invention, the first foam of the methods described herein above is a thermoplastic polymer and the second foam is a thermoset polymer.

In another embodiment of the present invention, the blowing agent used in preparing the first foam layer of the methods described herein above is a chemical blowing agent, an inorganic gas, an organic blowing agent, or combinations thereof.

In another embodiment of the present invention, the first foam of the methods described herein above comprises a thermoplastic polymer comprising a styrene polymer, a styrene and acrylonitrile copolymer, or mixtures thereof and the blowing agent is carbon dioxide, water or a combination thereof.

In another embodiment of the present invention, the second foam of the methods described herein above comprises a styrene polymer, a styrene and acrylonitrile copolymer, a mixture of a styrene and acrylonitrile copolymer, an epoxy polymer, a phenolic polymer, an urea-formaldehyde polymer, a polyisocyanurate polymer, or a polyurethane polymer.

Another embodiment of the present invention, is a shaped foam laminate article made by the methods of the herein above disclosed invention, preferably the shaped foam laminate article is a roof tile; an exterior facade panel; a hydronic floor heating insulation panel; a basement foundation panel; a shutter; an external coving; a decorative piece, such as a baluster, a pillar and the like; a roller shutter box; a thermal bridge breaker (having specific shapes); a door; a door panel, a door frame (e.g., filler piece); a window frame; a pipe shell; a pipe elbow; a pipe T-shape; a pipe connection box; or a partition wall panel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a foam plank.

FIG. 2 is a cross-sectional view of a foam laminate.

FIG. 2a is a detail of the cross-sectional view of the foam laminate of FIG. 2. FIG. 3 is an illustration of the step change in a shaped foam laminate article of the present invention.

FIG. 4 is a cross-sectional view of a forming tool with a foam laminate in the open position prior to shaping.

FIG. 5 is a cross-sectional view of a forming tool with a trimmed and shaped foam laminate in the closed position.

FIG. 6 is a cross-sectional view of a forming tool with a shaped foam laminate article in the open position after shaping.

FIG. 7 is a photograph of a shaping tool which imparts ribbed shapes.

FIG. 8 is a photograph of Example 1 shaped with the tool shown in FIG. 7.

FIG. 9 is a photograph of Example 2 shaped with the tool shown in FIG. 7

FIG. 10 is a photograph of Comparative Example A shaped with the tool shown in

FIG. 7

FIG. 11 is a photograph of Comparative Example B shaped with the tool shown in FIG. 7

FIG. 12 is a photograph of a shaping tool which imparts the shape of cedar shakes.

FIG. 13 is a photograph of Example 1 shaped with the tool shown in FIG. 12.

The shaped foam laminate article of the present invention comprises a foam laminate comprising at least a first foam layer bonded to a second foam layer wherein the shape is imparted into the non-bonded surface of the first foam layer. Further, the first foam of the first foam layer is not the same foam as the second foam of the second foam layer. The first foam layer has a vertical compressive balance (Rvfkst foam) of equal to or greater than 0.40. The second foam of the second foam layer has a vertical compressive strength (CSv_Second foam) equal to or greater then the vertical compressive strength of the first foam in the first foam layer (CSvfi_rst fo_am): CSv_seCond foam≥ CSvfi_rst fo_am- In another embodiment, the second foam layer is further differentiated from the first foam layer in that it demonstrates better insulating properties, i.e., it has a higher R- value per inch (or lower thermal conductivity): R-value/in_sec0nd foam > R-value/in_{first foam}.

The first foam layer is prepared from a foam plank 1 comprising a first foam composition. The foam plank 1 has a top (first surface) 10, a bottom (second surface) 11, a width 12 a thickness 13, and length (not depicted in drawing) FIG 1. In one embodiment, the foam plank 1 is made by an extrusion process and comprises 'skins'. A skin surface comprises a high density region formed on the top and bottom surface of a plank. After the foam plank is formed, a pressing surface is created, for example by removing a layer from the top or bottom surface or by cutting 14 the foam plank between the top 10 and bottom 11

surfaces to create two pressing surfaces the first 19 opposite the bottom surface 11 and the second 20 opposite the top surface 10.

A 'pressing surface' is defined as the resulting surface on a foam plank after a layer of foam has been removed. In all cases, the pressing surface is not a skin. Suitable methods that may be useful to remove a layer of foam are cutting using equipment such as milling equipment, band saws, computer numeric controlled (CNC) abrasive wire cutting machines, CNC hot wire cutting equipment and the like. When removing a layer, the same cutting methods just described may be used and other methods such as planning, grinding, grooving, or sanding may be used.

When a layer is removed from the top and/or bottom surface of a foam plank 1 and/or the foam plank is cut 14, the resulting foam structure(s) is referred to as a 'foam blank' . For example, in FIG. 1 when foam plank 1 is cut in half 14, it provides two foam blanks 15 and 16 each having a thickness 17 and 18 that is less than the original thickness of the foam plank 1. If the foam plank is cut in half, i.e., 17 equals 18, then foam blanks 15 and 16 are identical. A foam blank differs from a foam plank in that the foam blank has at least one pressing surface as described herein above. The foam blank is removed from and/or separated from the foam plank prior to shaping and/or laminating to the second foam layer. One or more additional cuts may be necessary to prepare the foam blank to the proper dimensions prior to shaping and laminating. A foam blank is the first foam layer of the foam laminate of the present invention.

A cut surface (e.g., the surface(s) resulting from the cut 14) of the foam blank 15 becomes the first pressing surface 19. This terminology applies whether the foam plank is cut in half (providing two foam blanks, each with a pressing surface) or only a few millimeters is cut or removed from the surface of the foam plank (providing a single foam blank with a single pressing surface). Multiple (e.g., 2, 3, 4, 5, or more) foam blanks may be cut from a single foam plank (multiple blanks require multiple cuts). The conventional foam blank is rectangular and results from a cut through, and parallel to, the top and bottom surfaces of the foam plank. A foam blank may have one or more pressing surface.

Another embodiment is the "near net-shaped foam blank". A near net-shaped foam blank is formed when the shape of the foam blank is similar to the final shape of the shaped foam laminate article. In a near net-shaped foam blank sometimes one or more cuts are made in a plane other than parallel to the top and bottom surfaces of the foam plank.

Typically, after the removing or cutting, the blank is at least about several millimeters thick to at most about 60 centimeters thick. Generally, when removing a layer, the amount of material removed is at least about a millimeter and may be any amount useful to perform the method such as 1.2, 1.4, 1.6, 1.8, 2, 2.5, 3, 3.5, 4, 5 millimeters or any subsequent amount determined to be useful such as an amount to remove any skin that is formed as a result of extruding the thermoplastic foam, but is typically no more than 10 millimeters. In another embodiment, the foam is cut and a layer is removed from the top or bottom surface opposite the cut surface to form two pressing surfaces.

In one embodiment, the foam blank having a pressing surface, has a density gradient from the pressing surface to the opposite surface of the foam blank. Generally, it is desirable to have a density gradient of at least 5 percent, 10 percent, 15 percent, 25 percent, 30 percent or even 35 percent from the pressing surface to the opposing surface of the foam plank. To illustrate the density gradient, if the density of the foam at the surface (i.e., within a millimeter or two of the surface) is 48 kilogram per cubic meter (kg/m ), the density would be for a 10 percent gradient either 43 or 53 kg/m at the center of the foam. Even though the density of the foam at the pressing surface of the foam blank may be less or greater than the density at the center of the foam plank it is prepared from, the density of the foam at the pressing surface of the foam blank is preferably less than the density at the center of said foam blank.

The foam laminate of the present invention has at least two foam layers, a first foam layer and a second foam layer. In the embodiment where the foam laminate is a 2-layer foam laminate, the first foam layer 15 is laminated to a second foam layer 2 to form a 2- layer foam laminate 3, FIG. 2. In all embodiments of the present invention, the second foam layer 2 is made from a second foam plank made from a second foam polymeric composition, different from the first foam polymeric composition. Typically, if the second foam layer is a plank made by an extrusion process, it may comprise skins. However, if the second foam layer is prepared from a second foam plank that has been cut from a thicker extruded foam plank or if the second foam plank is cut from a liquid dispensed foam bun or form, the second foam plank may have only one skin or no skins. The second foam plank 2 has a top (first surface) 20, a bottom (second surface) 21, a width 22, a thickness 23, and length (not depicted in the drawings). In one embodiment, the second foam layer has skins on both the top and bottom surfaces 20 and 21. In another embodiment, the second foam plank has only one skin, either the top surface 20 or the bottom surface 21, but not both. In yet another embodiment, the second foam plank has no skins on the top and bottom surfaces, 20 and 21 respectively.

The foam laminate of the present invention may have more than two layers, which may or may not be foam, for example, there may be 3, 4, 5, 6, 7, 8, etc. If there are more than two layers, there may be one or more (foam) layer between the first foam layer and the second foam layer or there may a first additional (foam) layer laminated to the surface of the second foam opposite the surface laminated to the first foam layer and/or there may be additional (foam) layers laminated to the first additional (foam) layer, or combinations there of. For example, if the first foam layer is designated by the letter A and the second foam layer is designated by the letter B and additional (foam) layers are designated C, D, E, F, G, and so on, AB would represent a 2-layer foam laminate. ACB would represent a 3-layer (foam) laminate with an additional (foam) layer (C) between A and B. Alternatively, a 3- layer laminate where the third (foam) layer (C) is laminated to the surface of the second layer not laminated to the first foam layer would be represented ABC. 4-layer (foam) laminates can be represented as ACBD, ABCD, ACBC, and the like. 5-layer (foam) laminates can be represented as ACBDE, ACEBD, ABCDE, ABDEC, ABECD, and so on. Additional layers are typically foam, but are not limited to foam. Additional layers are typically polymeric material, but are not limited to polymeric materials.

The first foam layer 15 is bonded to the second foam layer 2 by an adhesive means (forming an adhesive layer 4) to form a foam laminate 3. Any additional (foam) layers may also bonded by an adhesive means. Suitable materials for use as adhesives or in an adhesive layer may be the same or different between different layers. Any adhesive capable of bonding a specific layer to another layer is within the scope of the present invention. An effective type and amount of adhesive can be determined by one of ordinary skill in the art without undue experimentation for a given (foam) layer/(foam) layer combination. The adhesive layer 4 has a thickness 41. The foam laminate 3 has a width 32 and a thickness 33.

Not to be limited to the following adhesives, a suitable adhesive may be a compound such as a chemical adhesive which, for example can be a one-part or multiple part adhesive such as a two-component polyurethane liquid adhesive, for example a polyurethane or an epoxy; a film such as double sided tape or pressure sensitive adhesive (PSA); or another layer or film comprising a material which is compatible with (i.e., bonds to) both the first foam of the first foam layer and the second foam of the second foam layer.

Suitable materials for use as adhesives or in adhesive layers include those adhesive materials known in the art as useful with plastic films and foams, see USP 5,695,870, which is hereby incorporated by reference. Examples include polyolefin copolymers such as ethylene/vinyl acetate, ethylene/acrylic acid, ethylene/n-butyl acrylate, ethylene ionomers, ethylene/methylacrylate, and ethylene or propylene graft anhydrides. Other useful adhesives include urethanes, copolyesters and copolyamides, styrene block copolymers such as styrene/butadiene and styrene/isoprene polymers, acrylic polymers, and the like. The adhesives may be thermoplastic or curable thermoset polymers, and can include tacky, pressure-sensitive adhesives. The adhesive or adhesive layer is preferably recyclable within the foam board manufacturing process. The adhesive material must not negatively impact the physical integrity or properties of the (foam) layers to a substantial degree.

For example, suitable adhesives are foam craft adhesives such as 3M Styrofoam Spray Adhesive, adhesives based on dispersions, e.g. ACRONAL™ Acrylate Dispersions available from BASF, one-component polyurethane adhesive such as INSTASTIK™ available from The Dow Chemical Company, hot-melt adhesives, moisture-cured adhesives such as those described in US7217459B2, which is hereby incorporated by reference, single- or preferably two-component adhesives based on polyurethane resins or on epoxy resins, see USP 20080038516A1, which is hereby incorporated by reference, and the like.

Alternatively, mechanical means may be used to bond two or more layers of the present invention. For example, fasteners, snap fits, clips, mounting points, joints, channels, Velcro, and the like may be used. In this embodiment, there is no adhesive layer 4 between the first and second foam layers, or any layers which are bonded by this means.

Alternatively, thermal means may be used to bond or weld together two layers of the present invention, e.g., from heating and/or sonic (vibration) means. In this embodiment, there is no adhesive layer 4 between the first and second foam layers, or any layers which are bonded by this means.

Alternatively, physical means or chemical means may be used to bond or weld together two layers of the present invention.

Alternatively, one or more of thermal means, mechanical means, physical means, chemical means, and/or adhesive means, may be used in combination to bond the first foam layer to the second foam layer. To promote adhesion or bonding between two foam layers, one or both of the surfaces to be bonded may optionally be planed, grooved, scored, roughened, sanded, etc. to promote chemical and/or mechanical adhesion.

Each foam layer comprises a foam polymeric composition. As long as the first foam and second foam of the first foam layer and the second foam layer meet the above mentioned internal cell gas pressure criteria (first foam less than 1 atm), CSv criteria (CSvsecond foam≥ CSv_first f_oam ), and optional R-value criteria (R-value/in_{second foam} > R- value/infirst foam), they may be independently made from any foam polymeric composition. A foam polymeric composition comprises a continuous polymeric matrix material with cells defined therein. Cellular (foam) has the meaning commonly understood in the art in which a polymer has a substantially lowered apparent density comprised of cells that are closed or open. Closed cell means that the gas within that cell is isolated from another cell by the polymer walls forming the cell. Open cell means that the gas in that cell is not so restricted and is able to flow without passing through any polymer cell walls to the atmosphere. The foams in the foam laminate article of the present invention can independently be open or closed celled. A closed cell foam has less than 30 percent, preferably 20 percent or less, more preferably 10 percent or less and still more preferably 5 percent or less and most preferably one percent or less open cell content. A closed cell foam can have zero percent open cell content. Conversely, an open cell foam has 30 percent or more, preferably 50 percent or more, still more preferably 70 percent or more, yet more preferably 90 percent or more open cell content. An open cell foam can have 95 percent or more and even 100 percent open cell content. Unless otherwise noted, open cell content is determined according to American Society for Testing and Materials (ASTM) method D6226-05.

Desirably the foams of the foam laminate article comprise polymeric foam, which is a foam composition with a polymeric continuous matrix material (polymer matrix material). Any polymeric foam is suitable including extruded polymeric foam, expanded polymeric foam, free rise or restrained rise liquid dispensed polymeric foam, and molded polymeric foam. The foams may comprise, and desirably comprises as a continuous phase, independently a thermoplastic polymer matrix material and/or a thermoset polymer matrix material. In other words, one foam layer may be a thermoplastic polymeric foam and the other foam layer may be a thermoset polymeric foam, both foam layers may be thermoset polymeric foams, or both foam layers may be thermoplastic polymeric foams. Desirably, both the first and second foam polymeric matrix material has a thermoplastic polymeric continuous phase.

A shaped foam laminate article of the present invention can comprise or consist of one or more foam layer comprising a thermoset polymer, one or more foam layer comprising a thermoplastic polymer, or combinations or blends thereof. Suitable thermoset polymers for a foam layer include thermoset epoxy polymer, phenolic polymer, urea- formaldehyde polymer, polyisocyanurate polymer, polyurethane polymer, and the like.

Polyisocyanurate and polyurethane foam are particularly suitable for the second foam layer of the present invention. Polyurethane and polyisocyanurate foam structures are usually made by reacting two preformulated components, commonly called the A- component and the B-component by dispensing the liquid components (A and B sides) onto a facer, the components are allowed to react and foam, free rise or restrain rise as a bun or in a form, followed by cutting or machining the resulting foams into planks. The

preformulated components comprise an isocyanate and a polyol.

Polyurethane foams can be prepared by reacting the polyol and the isocyanate on a

0.7: 1 to 1.1: 1 equivalent basis. Polyisocyanurate foams can be advantageously prepared by reacting the polyisocyanate with a minor amount of polyol to provide about 0.10 to 0.70 hydroxyl equivalents of polyol per equivalent of polyisocyanate. Useful polyurethanes and polyisocyanurates and processes for making them are seen in USP 4,795,763, which is incorporated herein by reference.

Suitable polyisocyanurate foams and polyurethane foams for use in the second layer have a density of from about 10 kg/m 3 to about 150 kg/m 3 and most preferably from about

10 kg/m 3 to about 70 kg/m 3 according to ASTM D1622-88. The polyisocyanurate foams and polyurethane foams have an average cell size of from about 0.05 mm to about 5.0 mm and preferably from about 0.1 mm to about 1.5 mm according to ASTM D3576-77.

Suitable thermoplastic polymers include any one or any combination of more than one thermoplastic polymer. Olefinic polymers, alkenyl- aromatic homopolymers and copolymers comprising both olefinic and alkenyl aromatic components are suitable.

Examples of suitable olefinic polymers include homopolymers and copolymers of ethylene and propylene (e.g., polyethylene, polypropylene, and copolymers of polyethylene and polypropylene). Alkenyl- aromatic polymers such as polystyrene, polyphenylene oxide/polystyrene blends, and/or polyester are particularly suitable polymers for the foam article of the present invention. Desirably, the foam layers of the shaped foam laminate article of the present invention independently comprise a polymeric foam having a polymer matrix comprising or consisting of one or more than one alkenyl- aromatic polymer. An alkenyl- aromatic polymer is a polymer containing alkenyl aromatic monomers polymerized into the polymer structure. Alkenyl- aromatic polymer can be homopolymers, copolymers or blends of homopolymers and copolymers. Alkenyl-aromatic copolymers can be random copolymers, alternating copolymers, block copolymers, rubber modified, or any combination thereof and my be linear, branched or a mixture thereof.

Styrenic polymers are particularly desirably alkenyl-aromatic polymers. Styrenic polymers have styrene and/or substituted styrene monomer (e.g., alpha methyl styrene) polymerized in the polymer backbone and include both styrene homopolymer, copolymer and blends thereof. Polystyrene and high impact modified polystyrene are two preferred styrenic polymers.

Examples of styrenic copolymers suitable for the present invention include copolymers of styrene with one or more of the following: acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, itaconic acid, acrylonitrile, maleic anhydride, methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl methacrylate, vinyl acetate and butadiene.

Polystyrene (PS) is a preferred styrenic polymer for use in the foam articles of the present invention because of their good balance between cost property performance.

Styrene-acrylonitrile copolymer (SAN) is a particularly desirable alkenyl-aromatic polymer for use in the foam articles of the present invention because of its ease of manufacture and monomer availability. SAN copolymer can be a block copolymer or a random copolymer, and can be linear or branched. SAN provides higher water solubility than polystyrene homopolymer, thereby facilitating use of an aqueous blowing agent. SAN also has higher heat distortion temperature than polystyrene homopolymer, which provides for foam having a higher use temperature than a polystyrene homopolymer foam. Desirable embodiments of the present process employ polymer compositions that comprise, even consist of SAN. The one or more alkenyl-aromatic polymer, even the polymer composition itself may comprise or consist of a polymer blend of SAN with another polymer such as polystyrene homopolymer.

Whether the polymer composition contains only SAN, or SAN with other polymers, the acrylonitrile (AN) component of the SAN is desirably present at a concentration of 1 weight percent or more, preferably 5 weight percent or more, more preferably 10 weight percent or more based on the weight of all polymers in the polymer composition. The AN component of the SAN is desirably present at a concentration of 50 weight percent or less, typically 30 weight percent or less based on the weight of all polymers in the polymer composition. When AN is present at a concentration of less than 1 weight percent, the water solubility improvement is minimal over polystyrene unless another hydrophilic component is present. When AN is present at a concentration greater than 50 weight percent, the polymer composition tends to suffer from thermal instability while in a melt phase in an extruder.

The styrenic polymer may be of any useful weight average molecular weight (MW).

Illustratively, the molecular weight of a styrenic polymer or styrenic copolymer may be from 10,000 to 1,000,000. The molecular weight of a styrenic polymer is desirably less than about 200,000, which surprisingly aids in forming a shaped foam part retaining excellent surface finish and dimensional control. In ascending further preference, the molecular weight of a styrenic polymer or styrenic copolymer is less than about 190,000,

180,000, 175,000, 170,000, 165,000, 160,000, 155,000, 150,000, 145,000, 140,000, 135,000, 130,000, 125,000, 120,000, 115,000, 110,000, 105,000, 100,000, 95,000, and 90,000. For clarity, molecular weight herein is reported as weight average molecular weight unless explicitly stated otherwise. The molecular weight may be determined by any suitable method such as those known in the art.

Rubber modified homopolymers and copolymers of styrenic polymers are preferred styrenic polymers for use in the foam articles of the present invention, particularly when improved impact is desired. Such polymers include the rubber modified homopolymers and copolymers of styrene or alpha-methylstyrene with a copolymerizable comonomer.

Preferred comonomers include acrylonitrile which may be employed alone or in

combination with other comonomers particularly methylmethacrylate, methacrylonitrile, fumaronitrile and/or an N-arylmaleimide such as N-phenylmaleimide. Highly preferred copolymers contain from about 70 to about 80 percent styrene monomer and 30 to 20 percent acrylonitrile monomer.

Suitable rubbers include the well known homopolymers and copolymers of conjugated dienes, particularly butadiene, as well as other rubbery polymers such as olefin polymers, particularly copolymers of ethylene, propylene and optionally a nonconjugated diene, or acrylate rubbers, particularly homopolymers and copolymers of alkyl acrylates having from 4 to 6 carbons in the alkyl group. In addition, mixtures of the foregoing rubbery polymers may be employed if desired. Preferred rubbers are homopolymers of butadiene and copolymers thereof in an amount equal to or greater than about 5 weight percent, preferably equal to or greater than about 7 weight percent, more preferably equal to or greater than about 10 weight percent and even more preferably equal to or greater than 12 weight percent based on the total weight or the rubber modified styrenic polymer. Preferred rubbers present in an amount equal to or less than about 30 weight percent, preferably equal to or less than about 25 weight percent, more preferably equal to or less than about 20 weight percent and even more preferably equal to or less than 15 weight percent based on the total weight or the rubber modified styrenic polymer. Such rubber copolymers may be random or block copolymers and in addition may be hydrogenated to remove residual unsaturation.

The rubber modified homopolymers or copolymers are preferably prepared by a graft generating process such as by a bulk or solution polymerization or an emulsion polymerization of the copolymer in the presence of the rubbery polymer. Depending on the desired properties of the foam article, the rubbers' particle size may be large (for example greater than 2 micron) or small (for example less than 2 micron) and may be a monomodal average size or multimodal, i.e., mixtures of different size rubber particle sizes, for instance a mixture of large and small rubber particles. In the rubber grafting process various amounts of an ungrafted matrix of the homopolymer or copolymer are also formed. In the solution or bulk polymerization of a rubber modified (co)polymer of a vinyl aromatic monomer, a matrix (co)polymer is formed. The matrix further contains rubber particles having (co)polymer grafted thereto and occluded therein.

High impact poly styrene (HIPS) is a particularly desirable rubber-modified alkenyl- aromatic homopolymer for use in the foam articles of the present invention because of its good blend of cost and performance properties, requiring improved impact strength.

Butadiene, acrylonitrile, and styrene (ABS) terpolymer is a particularly desirable rubber-modified alkenyl- aromatic copolymer for use in the foam articles of the present invention because of its good blend of cost and performance properties, requiring improved impact strength and improved thermal properties.

Foam layers for use in the present invention may be prepared by any conceivable method. Suitable methods for preparing polymeric foam layers include batch processes (such as expanded bead foam processes), semi-batch processes (such as accumulative extrusion processes) and continuous processes such as extrusion foam and reactive foaming processes. Desirably, the process is a semi-batch or continuous extrusion process. Most preferably process comprises an extrusion process for thermoplastic polymers and a reactive foaming process, such as liquid dispensing for thermoset polymers.

An expanded bead foam process is a batch process that requires preparing a foamable polymer composition by incorporating a blowing agent into granules of polymer composition (for example, imbibing granules of a thermoplastic polymer composition with a blowing agent under pressure). Each bead becomes a foamable polymer composition. Often, though not necessarily, the foamable beads undergo at least two expansion steps. An initial expansion occurs by heating the granules above their softening temperature and allowing the blowing agent to expand the beads. A second expansion is often done with multiple beads in a mold and then exposing the beads to steam to further expand them and fuse them together. A bonding agent is commonly coated on the beads before the second expansion to facilitate bonding of the beads together. The resulting expanded bead foam has a characteristic continuous network of polymer skins throughout the foam. The polymer skin network corresponds to the surface of each individual bead and encompasses groups of cells throughout the foam. The network is of higher density than the portion of foam containing groups of cells that the network encompasses. Accumulative extrusion and extrusion processes produce foams that are free of such a polymer skin network.

A foamed layer can also be made in a reactive foaming process, in which precursor materials react in the presence of a blowing agent to form a cellular polymer. Polymers of this type are most commonly polyurethane, polyisocyanurates, and polyepoxides, especially structural polyurethane foams as described, for example, in USP 5,234,965 and 6,423,755, both hereby incorporated by reference. Typically, anisotropic characteristics are imparted to such foams by constraining the expanding reaction mixture in at least one direction while allowing it to expand freely or nearly freely in at least one orthogonal direction.

An extrusion process prepares a foamable polymer composition of a thermoplastic polymer with a blowing agent in an extruder by heating a thermoplastic polymer composition to soften it, mixing a blowing agent composition together with the softened thermoplastic polymer composition at a mixing temperature and mixing pressure that precludes expansion of the blowing agent to any meaningful extent (preferably, that precludes any blowing agent expansion) and then extruding (expelling) the foamable polymer composition through a die into an environment having a temperature and pressure below the mixing temperature and pressure. Upon expelling the foamable polymer composition into the lower pressure the blowing agent expands the thermoplastic polymer into a thermoplastic polymer foam. Desirably, the foamable polymer composition is cooled after mixing and prior to expelling it through the die. In a continuous process, the foamable polymer composition is expelled at an essentially constant rate into the lower pressure to enable essentially continuous foaming. An extruded foam can be a continuous, seamless structure, such as a sheet or profile, as opposed to a bead foam structure or other composition comprising multiple individual foams that are assembled together in order to maximize structural integrity and thermal insulating capability.

Accumulative extrusion is a semi-continuous extrusion process that comprises: 1) mixing a thermoplastic material and a blowing agent composition to form a foamable polymer composition; 2) extruding the foamable polymer composition into a holding zone maintained at a temperature and pressure which does not allow the foamable polymer composition to foam; the holding zone having a die defining an orifice opening into a zone of lower pressure at which the foamable polymer composition foams and an openable gate closing the die orifice; 3) periodically opening the gate while substantially concurrently applying mechanical pressure by means of a movable ram on the foamable polymer composition to eject it from the holding zone through the die orifice into the zone of lower pressure, and 4) allowing the ejected foamable polymer composition to expand to form the foam. USP 4,323,528, hereby incorporated by reference, discloses such a process in a context of making polyolefin foams, yet which is readily adaptable to aromatic polymer foam. USP 3,268,636 discloses the process when it takes place in an injection molding machine and the thermoplastic with blowing agent is injected into a mold and allowed to foam, this process is sometimes called structural foam molding.

Suitable blowing agents include one or any combination of more than one of the following: inorganic gases such as carbon dioxide, argon, nitrogen, and air; organic blowing agents such as water, aliphatic and cyclic hydrocarbons having from one to nine carbons including methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane, cyclobutane, and cyclopentane; fully and partially halogenated alkanes and alkenes having from one to five carbons, preferably that are chlorine-free (e.g.,

difluoromethane (HFC-32), perfluoromethane, ethyl fluoride (HFC-161), 1,1,- difluoroethane (HFC-152a), 1,1,1-trifluoroethane (HFC-143a), 1,1,2,2-tetrafluoroethane (HFC- 134), 1,1,1,2 tetrafluoroethane (HFC- 134a), pentafluoroethane (HFC-125), perfluoroethane, 2,2-difluoropropane (HFC-272fb), 1,1,1-trifluoropropane (HFC-263fb), 1,1, 1,2,3,3, 3-heptafluoropropane (HFC-227ea), 1,1,1,3,3-pentafluoropropane (HFC-245fa), and 1,1,1,3,3-pentafluorobutane (HFC-365mfc)); fully and partially halogenated polymers and copolymers, desirably fluorinated polymers and copolymers, even more preferably chlorine-free fluorintated polymers and copolymers; aliphatic alcohols having from one to five carbons such as methanol, ethanol, n-propanol, and isopropanol; carbonyl containing compounds such as acetone, 2-butanone, and acetaldehyde; ether containing compounds such as dimethyl ether, diethyl ether, methyl ethyl ether; carboxylate compounds such as methyl formate, methyl acetate, ethyl acetate; carboxylic acid and chemical blowing agents such as azodicarbonamide, azodiisobutyronitrile, benzenesulfo-hydrazide, 4,4-oxybenzene sulfonyl semi-carbazide, p-toluene sulfonyl semi-carbazide, barium azodicarboxylate, Ν,Ν'- dimethyl-N,N'-dinitrosoterephthalamide, trihydrazino triazine and sodium bicarbonate.

The amount of blowing agent can be determined by one of ordinary skill in the art without undue experimentation for a given thermoplastic to be foamed based on the type thermoplastic polymer, the type of blowing agent, the shape/configuration of the foam article, and the desired foam density. Generally, the foam article may have a density of from about 16 kilograms per cubic meter (kg/m 3 ) to about 200 kg/m 3 or more. The foam density, typically, is selected depending on the particular application. Preferably the foam density is equal to or less than about 160 kg/m , more preferably equal to or less than about 120 kg/m 3 , and most preferably equal to or less than about 100 kg/m 3.

The cells of a foam layer may have an average size (largest dimension) of from about 0.05 to about 5.0 millimeter (mm), especially from about 0.1 to about 3.0 mm, as measured by ASTM D-3576-98.

In one embodiment of the present invention, to facilitate the shape retention and appearance in the shaped foam laminate article after pressing the foam laminate or the first foam blank, preferably the first foam of the first foam layer comprises from 10 to 100 percent closed cells, preferably from 95 to 100 percent closed cells, it is desirable that the average internal cell gas pressure for the first foam is equal to or less than 1 atmosphere (atm).

In one embodiment, it is desirable that the internal cell gas pressure in the first foam is equal to or less than atmospheric pressure to minimize the potential for spring back of the foam after pressing causing less than desirable shape retention. Preferably, for the first foam, the average internal pressure of the closed cells (i.e., average closed internal cell gas pressure) is equal to or less than 1 atmosphere, preferably equal to or less than 0.95 atmosphere, more preferably equal to or less than 0.90 atmosphere, even more preferably equal to or less than 0.85 atmosphere, and most preferably equal to or less than 0.80 atmosphere.

In one embodiment, it is desirable that the internal cell gas pressure in the second foam is greater than the internal cell gas pressure in the first foam, preferably the internal cell gas pressure in the second foam is greater than atmospheric pressure, more preferably it is equal to or greater than 1.1 atm, more preferably it is equal to or greater than 1.2 atm, more preferably it is equal to or greater than 1.3 atm, and even more preferably the internal gas cell pressure of the second foam is equal to or greater than 1.4 atm.

Internal cell gas pressures may be determined from standard cell pressure versus aging curves. Alternatively, internal cell gas pressure can be determined according to ASTM D7132-05 if the initial time the foam is made is known. If the initial time the foam is made is unknown, then the following alternative empirical method can used: The average internal gas pressure of the closed cells from three samples is determined on cubes of foam measuring approximately 50mm. One cube is placed in a furnace set to 85°C under vacuum of at least 1 Torr or less, a second cube is placed in a furnace set to 85°C at 0.5 atm, and the third cube is placed in the furnace at 85°C at atmospheric pressure. After 12 hours, each sample is allowed to cool to room temperature in the furnace without changing the pressure in the furnace. After the cube is cool, it is removed from the furnace and the maximum dimensional change in each orthogonal direction is determined. The maximum linear dimensional change is then determined from the measurements and plotted against the pressure and curve fit with a straight line using linear regression analysis with average internal cell pressure being the pressure where the fitted line has zero dimensional change.

The compressive strength of a foam plank (or blank) is determined in accordance with industry standard test methods such as ASTM D1621 or modifications thereof. The compressive strength of a foam is established when the compressive strength of the foam is evaluated in three orthogonal directions, E, V and H, where E is the direction of extrusion, V is the direction of vertical expansion after it exits the extrusion die and H is the direction of horizontal expansion of the foam after it exits the extrusion die.

These measured compressive strengths, C_E, C_V and C_H, respectively, are related to the sum of these compressive strengths, C_T, such that for the first foam, at least one of C_E/C_T, C_V C_T and C_H C_T, has a value of at least 0.40, preferably a value of at least 0.45 and most preferably a value of at least 0.50. In one embodiment, for the first foam, the pressing direction is parallel to the maximum compressive strength value in the foam and is equal to or greater than 0.40.

In one embodiment, the ratio of the vertical compressive strength of the second foam to the vertical compressive strength of the first foam (CSv_seCond foam : CSv_first foam) is equal to 1, more preferably greater than 1, more preferably equal to or greater than 1.1, more preferably equal to or greater than 1.2, more preferably equal to or greater than 1.3, even more preferably equal to or greater than 1.4.

The polymer compositions of the first foam and second foam of the present invention may contain additives, typically dispersed within the continuous matrix material. The additives in the first foam may be the same, different, partially the same/partially different than the additives in the second foam. Common additives include any one or combination of more than one of the following: infrared attenuating agents (for example, carbon black, graphite, metal flake, titanium dioxide); clays such as natural absorbent clays (for example, kaolinite and montmorillonite) and synthetic clays; nucleating agents (for example, talc and magnesium silicate); fillers such as glass or polymeric fibers or glass or polymeric beads; flame retardants (for example, brominated flame retardants such as brominated polymers, hexabromocyclododecane, phosphorous flame retardants such as triphenylphosphate, and flame retardant packages that may including synergists such as, or example, dicumyl and polycumyl); lubricants (for example, calcium stearate and barium stearate); acid scavengers (for example, magnesium oxide and tetrasodium pyrophosphate); UV light stabilizers; thermal stabilizers; and colorants such as dyes and/or pigments.

In one embodiment of the present invention, a shaped foam laminate article 5 of the present invention is prepared from a foam laminate 3 which is prepared by laminating a first foam layer 15 made from a first foamed polymer to a second foam layer 2 made from a second foamed polymer as described hereinabove wherein the first foam layer 15 is bonded to the second foam layer 2 and further shaped to give a shaped foam laminate article 5. In the present invention, the first foam layer 15 of the shaped foam laminate article 5 may be (1) shaped prior to bonding to the second foam layer 2 or (2) the first foam layer 15 and the second foam layer 2 are first bonded together to form a foam laminate 3 having at least two foam layers then subsequently shaped to form the shaped foam laminate article 5 of the present invention. As defined herein, shaped means the foamed article typically has one or more contour that create a step change (impression) in height 50 of at least 1 millimeter or more in the shaped foam laminate article 5 having thickness 51 as shown in FIG. 3. A shaped foam laminate article has at least one surface that is not planar.

A particularly useful method to shape foam laminate articles is to start from a foam laminate comprising a first foam layer which has been extruded from a first thermoplastic comprising a blowing agent forming a first plank and a second foam layer which has been extruded from a second thermoplastic comprising a blowing agent forming a second plank. As per convention, but not limited by, the extrusion of a plank is taken to be horizontally extruded (the direction of extrusion is orthogonal to the direction of gravity). Using such convention, the plank' s top surface 10 is that farthest from the ground and the plank' s bottom surface 11 is that closest to the ground, with the height of the foam (thickness) 13 being orthogonal to the ground when being extruded.

The foam laminate 3 prior to contacting with a forming tool may be cut to fit into a tool, or may be cut simultaneously, such as in die cutting where the die cutting apparatus is set up such that during the cutting, the shape is simultaneously pressed into the pressing surface, in other words, the foam is compressed into the desired shape. Lastly, the final shape may be cut from a pressed foam laminate or first foam blank, for example, the foam laminate 3 or first foam blank may be roll pressed to provide the desired shape into the pressing surface and subsequently the desired shaped foam laminate article is cut from the undesired pressed or unpressed foam laminate or first foam blank. When cutting the foam, any suitable method may be used, such as those known in the art and those described herein for cutting the foam to form a shaped foam laminate article and/or pressing surface(s). In addition, methods that involve heat may also be used to cut the foam since the pressed shape has already been formed in the pressing surface.

In one embodiment of the present invention, the first foam layer 15, the second foam layer 2, both the first and second foam layers 15 and 2, the foam laminate 3, and/or the shaped foam laminate article 5 may be perforated. The first foam layer 15, the second foam layer 2, both the first and second foam layers 15 and 2, the foam laminate 3, and/or the shaped foam laminate article 5 may have a plurality of perforations. Perforation is defined herein to mean one or more hole which passes partially into and/or entirely through the a foam, a foam layer, and/or a foam laminate. Perforation may occur at any time, in other words, it may be done to the foam plank and/or foam blank and/or the foam laminate prior to shaping, to the shaped foam laminate article, or any combination. The perforations may extend partially into, but not through one or both sides of the foam plank, foam blank, foam laminate, or shaped foam laminate article. Alternatively, the perforations may extend through the foam plank, foam blank, foam laminate, or shaped foam laminate article, for instance, for a shaped foam laminate article made from a foam laminate, the perforations may extend through the depth of the foam laminate such that there is an opening through the foam from the upper surface 19 to the lower surface 21. The foam may be perforated by any acceptable means.

Perforating the foam laminate article may comprise puncturing the foam article with a one or more of pointed, sharp objects in the nature of a needle, pin, spike, nail, or the like. However, perforating may be accomplished by other means than sharp, pointed objects such as drilling, laser cutting, high-pressure fluid cutting, air guns, projectiles, or the like. The perforations may be made in like manner as disclosed in USP 5,424,016, which is hereby incorporated by reference.

The pressing surface(s) of the foam laminate 3 is contacted with a forming tool such as a die face (FIG. 4 to FIG. 6). Herein die face means any tool having an impressed shape that when pressed into the pressing surface of the first foam layer of the foam laminate will cause the foam of the first layer to take the shape of the die face. That is, the material making up the die face is such that it does not deform when pressed against the foam laminate, but the first foam layer 15 of the foam laminate 3 deforms to form and retain the desired shape of the die face. Preferably the second foam layer of the foam laminate compresses less than 30 percent of its original thickness, more preferably less than 20 percent, even more preferably less than 10 percent of its original thickness, and even more preferably there is no plastic deformation (i.e., irreversible deformation) as a result of the pressing process.

Typically when pressing, at least a portion of the foam laminate or first foam blank is pressed such that the first foam layer 15 or first foam blank is compressed to a thickness of 95 percent or less of the to be pressed foam thickness (original foam blank thickness) 17, which for some foams corresponds to just exceeding the yield stress of the foam. Likewise, when pressing the first foam layer or first foam blank, the maximum deformation of the first foam layer or first foam blank (elastically deforming the foam) is not less than 20 percent of the to be pressed foam thickness 17 of the first foam layer or first foam blank. The forming tool such as a die face, because a shape is most often desired, typically has contours that create an impression (step change) in height 50 of at least a millimeter in the shaped foam laminate article 5 having thickness 51 as shown in FIG 3. The

height/depth 50 of an impression may be measured using any suitable technique such as contact measurement techniques (e.g., coordinate measuring machines, dial gauges, contour templates) and non-contact techniques such as optical methods including laser methods. The height of the step change 50 may be greater than 1 millimeter such as 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 9 and 10 millimeters to a height that is to a point where there are no more foam cells to collapse such that pressing further starts to elastically deform the plastic (polymer) of the foam.

The step change, surprisingly, may be formed where the foam undergoes shear. For example, the foam may have a shear angle 53 of about 45° to about 90° from the pressing surface 19 of the shaped foam laminate article 5 in a step change 50. It is understood that the shear angle may not be linear, but may have some curvature, with the angle in these cases being an average over the curvature. The angle surprisingly may be greater than 60°, 75° or even by 90° while still maintaining an excellent finish and appearance.

In one embodiment of the present invention, neither the forming tool, e.g., the die face and/or mold, nor the foam laminate and/or first foam blank are heated (i.e., the foam is shaped at ambient temperature, which is defined herein to be 15-30°C).

In another aspect of the invention, the first foam is a foam having a higher concentration of open cells at the pressing surface (of the first foam layer or first foam blank) than the concentration of open cells within the foam. In this aspect of the invention the first foam may be any thermoplastic foam such as the extruded styrenic polymer foam described above. It may also be any other styrenic polymeric foam such as those known in the art including, for example, where the blowing agent is added to polymer beads, typically under pressure, as described by USP 4,485,193.

With respect to this open cell gradient, the concentration of open cells is determined microscopically and is the number of open cells per total cells at the surface.

Generally, the amount of open cells in this aspect of the invention at the surface is at least 5 percent to completely open cell. Desirably, the open cells at the surface is at least in ascending order of 6 percent, 7 percent, 8 percent, 10 percent, 20 percent, 30 percent, 40 percent, 50 percent, 60 percent, 70 percent, 80 percent, 90 percent and completely open cell at the surface. The first foam may have the open cells formed at the surface by mechanical means such as planing, machining, cutting, etc., or open cells may be induced chemically, for example, by use of suitable surfactants to burst closed cells at the surface.

In one embodiment of the present invention, the first foam surface with the higher concentration of open cells is contacted with a die face and pressed as described above, the mold faces may or may not be heated and the foam laminate may or may not be heated. However, in the embodiment where the foam laminate is not heated and the mold faces are heated, improved surface contour and appearance may be possible, whereas when doing the same with a foam without such open cells at the surface, the appearance of the foam may be degraded.

In one embodiment of the present invention, a molding machine, sometimes referred to as a press, is used to impart shape to the pressing surface of the foam laminate or first foam blank to form a shaped foam laminate article of the present invention. This process is often referred to as discontinuous as it consists of a cycle where a foam laminate or first foam blank (or first foam layer) is placed in an open mold, the mold closes to form a shaped foam laminate article or shaped foam article (or shaped first foam layer), then after the shaped article is formed, the mold opens. The shaped foam laminate or shaped foam article (shaped first foam layer) is removed from the mold, a new foam laminate or first foam blank (first foam layer) is inserted into the mold and the process repeated. This process is demonstrated for a foam laminate in FIG. 4 to FIG. 6.

When using a press with a forming tool, such as a mold, the mold commonly comprises one or two halves (only one mold half is shown in the accompanying drawings). If present, one mold half is affixed or mounted to the stationary platen 80 (sometimes referred to as the core side or stationary forming surface) and the other mold half 70 is affixed to the moveable platen 90 (sometimes referred to as the cavity side or movable forming surface) and moving with it, as shown in FIG. 4 to FIG. 6. The shape of the article will dictate the design and complexity of the forming tool. In one embodiment of the present invention, the mold half with the cavity is affixed to the movable platen and the stationary forming surface is the stationary platen itself 80. In this embodiment, the stationary forming surface is flat and imparts no shape to the foam laminate while the movable forming surface, or cavity, has a defined shape which is imparted into the pressing surface 19 of the first foam layer 15 of the foam laminate 3 when impressed upon the foam laminate FIG. 4 to FIG. 6. In another embodiment of the present invention (not illustrated in the accompanying drawings), the foam laminate comprises a third foam layer (C), wherein the third foam layer (C) is laminated to the second foam layer (B) opposite the surface laminated to the first foam layer (A), its structure is represented as: ABC. In this embodiment, the third foam layer comprises a third foam, which may be the same or different than the first foam, but, like the second foam, must have a vertical compressive balance equal to or greater than 0.40 and an internal cell gas pressure less than 1 atmosphere. In this embodiment, both the stationary and movable forming surfaces of the forming tool impart shape to both sides of the foam laminate, the shape imparted to each side may be the same or different.

In the shaping step of the method of the present invention, the surface of the foam laminate 21 opposite the pressing surface 19 of the foam laminate 3 is placed on a stationary forming surface, such as a stationary platen 80. A movable platen 90 which can move toward or away from the stationary platen on which the foam laminate is placed comprises a movable forming surface of the forming tool 70, for example, a single cavity mold or optionally a multiple cavity mold. To shape the foam, the movable platen moves towards the stationary platen such that the pressing surface 19 of the foam laminate 3 is contacted and pressed with the movable forming surface of the forming tool 70. For a multi-cavity mold, each cavity may be identical in shape or there may be as many different shapes as cavities or there may be a combination of multiple cavities with the same first shape in combination with multiple cavities with one or more shapes different than the first shape. The layout of cavities in a multi-cavity mold may be side by side, in tandem, or any other desirable configuration. A multi-cavity mold produces more than one shaped article in a plank per molding cycle.

In one embodiment of the present invention, the shaping/trimming steps occur concurrently. The periphery of each mold cavity 60 is defined by a trimming rib 71 with a thickness 72, a height 73, an inside surface 74, an outside surface 75, and a trimming end 76. It is the rib inside surface 74, or the inner perimeter of the trimming rib, that defines the outline of the cavity. The trimming rib separates the shaped foam laminate article 5 from the surrounding continuous unshaped foam plank 100.

In one embodiment of the present method, the forming tool is not heated.

In another embodiment of the present method, the forming tool is heated. In this embodiment, the forming tool, such as a die face, contact time with the foam laminate is typically from about 0.1 second to about 60 seconds. Preferably, the dwell time is at least about 1 second to at most about 45 seconds. When pressing with a heated forming tool such as a die face, the temperature of the die face is not so hot or held for too long a time such that the foam is degraded. Depending on the thermoplastic(s) employed, the temperature of the die face is about 50°C to about 200°C. Preferably, the temperature is at least about 60°, more preferably at least about 70°C, even more preferably at least about 80°C and most preferably at least about 90°C to preferably at most about 190°, more preferably at most about 180°, even more preferably at most about 170°C and most preferably at most about 160°C.

Alternatively, one embodiment of the process of the present invention comprises a continuous shaping step (not depicted in the drawings) wherein the foam laminate or first foam blank is shaped with a shaping roll comprising the steps of (i) shaping the one or more pressing surface of the first foam layer or first foam blank by a continuous process through one or more sets of rolls wherein one or more roll has a roll face having a defined shape which when pressed into the pressing surface of the first foam layer of the foam laminate or first foam blank provides a shaped foam laminate article with the shape of the roll face or a shaped first foam layer with the shape of the roll face.

The forming roll face, because a shape is most often desired, typically has contours that create an impression (step change) in height 50 of at least a millimeter in the shaped foam article 5 having thickness 51 as shown in FIG. 3.

In a continuous process wherein shape is imparted from rolls, one or more of the rolls may be coated, for example with chrome, polytetrafluoroethane (PTFE, e.g.,

TEFLON™), a silicone compound (coating or spray applied), or the like.

In one embodiment of the continuous method of the present invention, the foam laminate and/or first foam blank may be heated prior to shaping through one or more sets of rolls. Suitable temperatures will depend on the composition of the foam laminate and/or first foam layer as well as its thickness. In a preferred embodiment, the foam laminate and/or first foam blank in the present method is shaped at ambient temperature. The shaping rolls may or may not be heated; preferably the shaping rolls are at ambient temperature.

One embodiment of the present invention is a method to prepare a shaped foam laminate article comprising a first foam layer and a second foam layer comprising the steps of (A) preparing a foam laminate by the steps comprising: (i) preparing a first foam layer from a first foam blank by the steps comprising (i.a) extruding a first thermoplastic polymer composition with a blowing agent to form a first thermoplastic polymer foam plank, the first foam plank having a thickness, a top surface, and a bottom surface in which said surfaces lie in the plane defined by the direction of extrusion and the width of the first foam plank, wherein the first foam plank has a vertical compressive balance equal to or greater than 0.4 and an internal cell gas pressure leas than 1 atmosphere and (i.b) forming a first foam blank from the first foam plank by preparing one or more pressing surface wherein the resulting first foam blank has a first pressing surface and a second surface, (ii) preparing a second foam layer from a second foam plank by the steps comprising: (ii.a) foaming a second polymer composition with a blowing agent to form a second polymer foam plank, the second foam plank having a thickness, a top surface, and a bottom surface, wherein the second foam plank has a vertical compressive strength greater than the vertical compressive strength of the first foam layer, and (iii) laminating the second surface (i.e., the surface opposite the pressing surface) of the first foam blank to one of the surfaces (either top or bottom) of the second foam plank by an adhesive means to form a 2-layered foam laminate, and (B) providing shape to the first foam layer of the foam laminate by: (i) contacting the pressing surface of the first foam layer with a mold and (ii) pressing the pressing surface of the first foam layer such that a shaped foam laminate article is formed.

Alternatively, shape may be provided to the first foam layer prior to laminating to the second foam layer. In this embodiment of the present invention, a shaped foam laminate article comprising a first foam layer and a second foam layer is prepared by the method comprising the steps of (i) preparing a first foam layer by the steps comprising: (i.a) extruding a first thermoplastic polymer composition with a blowing agent to form a first thermoplastic polymer foam plank, the first foam plank having a thickness, a top surface, and a bottom surface in which said surfaces lie in the plane defined by the direction of extrusion and the width of the first foam plank, wherein the first foam plank has a vertical compressive balance equal to or greater than 0.4 and an internal cell gas pressure less than 1 atmosphere and (i.b) forming a first foam blank from the first foam plank by preparing one or more pressing surface wherein the resulting first foam blank has a first pressing surface and a second surface, wherein said first foam blank is the first foam layer, (ii) preparing a second foam layer from a second foam plank by the steps comprising: (ii.a) foaming a second polymer composition to form a second foam plank, the second foam plank having a thickness, a top surface, and a bottom surface, wherein the second foam plank has a vertical compressive strength equal to or greater than the vertical compressive strength of the first foam plank, wherein said second foam plank is the second foam layer, (iii) providing shape to the first foam layer by: (i) contacting the pressing surface of the first foam layer with a mold and (ii) pressing the pressing surface of the first foam layer such that a shaped first foam layer is formed, and (iv) bonding the second surface of the shaped first foam layer to a surface of the second foam layer to form a shaped foam laminate.

The shape of the foam laminate article is only limited by the ability to shape a foam laminate or a foam blank.

In a preferred embodiment of the present invention, the second foam layer of the shaped foam laminate article, and method to make said article, provide an article with improved insulation properties as compared to the insulation properties of the first foam layer alone. The R- value per inch of the second foam layer is greater than the R- value per inch of the first foam layer, preferably it is greater by an amount of at least 1, more preferably it is greater by an amount of at least 1.05, more preferably it is greater by an amount of at least 1.1, more preferably it is greater by an amount of at least 1.2, and even more preferably it is greater by an amount of at least 1.25. For example, if the R- value per inch of the first foam is 3, the R- value per inch of the second foam is greater than 3, preferably equal to or greater than 4, more preferably equal to or greater than 4.05, more preferably equal to or greater than 4.1, more preferably equal to or greater than 4.2, and even more preferably equal to or greater than 4.25.

In another embodiment, the R- value per inch for a foam laminate of the present invention comprising a first foam layer and a second foam layer of a specified thickness is greater than the R- value per inch of a first foam layer of the same first foam having the same thickness as the foam laminate. In other words, a 2 inch foam laminate of the present invention having a first foam layer of a first foam and a second foam layer of a second foam has a greater R-value per inch than a 2 inch foam layer comprising only the first foam.

Preferably, the R-value per inch for a foam laminate of the present invention comprising a first foam layer and a second foam layer of a specified thickness is equal to or greater than 1.05 times than the R-value per inch of a first foam layer of the same first foam having the same thickness as the foam laminate, more preferably equal to or greater than 1.1 times, more preferably equal to or greater than 1.15 times, more preferably equal to or greater than 1.2 times, and even more preferably the R-value per inch for a foam laminate of the present invention comprising a first foam layer and a second foam layer of a specified thickness is equal to or greater than 1.25 times the R-value per inch of a first foam layer of the same first foam having the same thickness as the foam laminate.

The shaped foam laminate article of the present invention is particularly suited for application to the exterior of a building, for example, a roof tile; an exterior facade panel; a hydronic floor heating insulation panel; a basement foundation panel; shutters; external covings; decorative pieces, such as baluster, pillars and the like; a roller shutter box; a thermal bridge breaker (having specific shapes); doors; door panels, door frames (e.g., filler piece); window frames; pipe shells; pipe elbows; pipe T-shapes; pipe connection boxes; partition wall panels; and the like.

TEST METHODS

The density profile through the thickness of a foam layer is tested using a QMS Density Profiler, model QDP-01X, from Quintek Measurement Systems, Inc. Knoxville, TN. The High Voltage kV Control was set to 90 percent, the High Voltage Current Control was set to 23 percent and the Detector Voltage was approximately 8v. Data points were collected every 0.06 mm throughout the thickness of the foam. Approximate thickness of the foam samples in the plane of the x-ray path was 2 inches. Mass absorption coefficients were calculated for each sample individually, based on the measured linear density of the foam part being tested. The skin density, p_skin , was reported as a maximum value whereas the core density, p_core , was averaged within an approximate 5 mm range. The density gradient, in units of percentage, was then computed in accordance with the following equation:

Density Gradient ( percent) = 100 · ^^{Pcore ~ ' Pskin} ^

P skin

Compressive properties of each foam product are characterized in accordance with ASTM D1621 test conditions. All tests are performed with an INSTRON™ 8511 universal testing machine equipped with a 2,248 pound (10,000 N) load cell. Crosshead displacement is measured via a linear variable differential transformer (LVDT) incorporated in the INSTRON test equipment. The crosshead velocity of the moving platen is programmed to a specified rate of 0.1 in/min (2.54 mm/min) per inch (25.4 mm) of specimen thickness. Transient force and displacement data were recorded at a sampling rate of 10 Hz respectively. The compressive strength of each foam specimen is calculated in accordance with ASTM D1621 while the total compressive strength, CST, is computed as follows:

CST = Csv + CSE + CSH where C_sv, C_SE and C_SH correspond to the compressive strength in the vertical, extrusion and horizontal direction respectively. Thus, the compressive balance, R, in each direction can be computed as shown below:

Open cell content is determined by ASTM D6226 and measured using an

Archimedes method on a 25mm by 25mm by 50mm foam sample and the value is reported as mean open cell content in percent.

While certain embodiments of the present invention are described in the following example, it will be apparent that considerable variations and modifications of these specific embodiments can be made without departing from the scope of the present invention as defined by a proper interpretation of the following claims.

Examples 1 and 2 and Comparative Examples A and B are foam laminates made by laminating a first foam layer to a second foam layer derived from commercially available styrenic foam planks. The styrenic foam planks from which the first and second foam layers are derived are described herein below:

"IMPAXX™ 300 Foam Plank" is available from The Dow Chemical Co., Midland, MI. This foam plank is an extruded styrenic foam with dimensions measuring 110mm by 600mm by 2,200mm in the thickness, width and length directions respectively having a density of 36 kilograms per cubic meter (kg/m³) and 3 millimeter (mm) to 5mm of the surface to be formed is removed by planing. The polystyrene has a weight average molecular weight of 146,000, the blowing agent is C0₂, and the internal cell gas pressure is about 0.6 atm.

"IMPAXX 500 Foam Plank" is available from The Dow Chemical Co., Midland, ML

This foam plank is an extruded styrenic foam with dimensions measuring 110mm by 600mm by 2,200mm in the thickness, width and length directions respectively having a density of 40 kilograms per cubic meter (kg/m³) and 3 millimeter (mm) to 5mm of the surface to be formed is removed by planing. The polystyrene has a weight average molecular weight of 146,000, the blowing agent is C0₂, and the internal cell gas pressure is about 0.8 atm. "SCOREBOARD™ Foam Plank" is commercially available from The Dow

Chemical Co., Midland, MI. This foam plank is an extruded styrenic foam with dimensions measuring 51mm by 1220mm by 2440mm the thickness, width and length directions, respectively, having a density of 27 kg/m³ and the surface to be formed contains the skin from the manufacturing process (i.e., not planed). The blowing agent comprises HFC-134a, and the internal cell gas pressure is about 1.3 to 1.4 atm.

"HIGHLOAD™ 60 (HI 60) Foam Plank" is commercially available from The Dow Chemical Co., Midland, MI. This foam plank is an extruded styrenic foam with dimensions measuring 76mm by 610mm by 2440mm in the thickness, width and length directions respectively having a density of 37.4 kg/m³ and the surface to be formed contains the skin from the manufacturing process (i.e., not planed). The blowing agent comprises HFC-134a and the internal cell gas pressure is about 1.3 to 1.4 atm.

"HIGHLOAD™ 100 (HI 100) Foam Plank" is commercially available from The Dow Chemical Co., Midland, MI. This foam plank is an extruded styrenic foam with dimensions measuring 76mm by 610mm by 2440mm in the thickness, width and length directions respectively having a density of 68.3 kg/m³ and the surface to be formed contains the skin from the manufacturing process (i.e., not planed). The blowing agent comprises HFC-134a and the internal cell gas pressure is about 1.3 to 1.4 atm.

The vertical compressive balance, density, open cell content, and internal cell gas pressure for the commercial foam boards used to make Examples 1 and 2 and Comparative Examples A and B are listed in Table 1.

All foam planks are extruded having a skin surface which comprises a high density region formed on the top and bottom surface of a plank whereas a planed surface condition comprises a skin plank that is passed through an on-line planer to remove 3 -5mm of the skin region from the top and bottom surface of a plank respectively.

Compressive properties of each foam product are characterized in accordance with ASTM D1621 test conditions as described herein above. All testing was conducted in a controlled temperature environment of 72°F (23°C) and 50 percent relative humidity.

Nominal, or mean, density is reported herein above is from 1) the mass recorded from a Mettler- Toledo SB8001 high precision weighing balance and 2) cubical specimen dimensions recorded via Mitutoyo (Model No. CD-6"CS) digital caliper of replicate (N=9) cubical specimens fabricated from each XPS foam plank. Open cell content is determined by ASTM D6226 as described herein above and the value is reported as mean open cell content in percent.

Internal cell gas pressure is determined from standard cell pressure versus aging curve.

Table 1

Foam laminates are formed from 50mm thick foam layers. 50mm thick foam sheets are prepared from each of the commercially available foam planks in excess of 50mm (2 in.) thickness using a Baumer computer numeric control (CNC) abrasive wire saw. The 50mm thick foam sheets are then cut down to 355mm (14 in) square blanks using a band saw. Next, 100mm thick foam laminates are prepared by adhering two 50mm foam blanks using LOCTITE PL Premium polyurethane construction adhesive.

The adhering surfaces of the foam blanks are grooved or scored manually with a steel tooth tool. The adhered surface for the IMPAXX foam blanks, the first foam layers, is the surface opposite the cut or core region of the blank (i.e., the planed surface) so that the pressing surface (i.e., the cut or core side of foam blank) will be against the surface of the forming tool respectively. It is not critical whether the skin surface or the cut surface of the second foam layer is laminated to the planed surface of the first foam layer, however, in Examples 1 and 2 and Comparative Examples A and B, it is the cut surface.

The polyurethane (PU) adhesive is dispensed on both surfaces of the foam blanks and evenly distributed to form a thin film (typically about l-2mm thick) of adhesive across the surfaces of both foam blanks. The blanks are positioned manually and a dead weight of 70 pounds is applied for approximately 24 hours prior to removal.

The first foam layers and second foam layers for the Examples and Comparative Examples are given in Table 2: Table 2

Square samples measuring 305mm (12 in) of each laminate are prepared using a band saw. Each sample is pressed using a PHI hydraulic compression press having two flat platens, in other words, the foam laminates are just compressed, not shaped. Prior to pressing, two steel stop blocks measuring 74.86mm in height are placed on the movable (e.g., lower) platen alongside the 100mm foam laminate sample. The total thickness "Total" as well as the thickness of each respective foam layer, t_lst and t_2n(j, for each laminate is measured using Mitutoyo Absolute Digimatic (Model No. CD-6"CS) calipers prior to forming. The laminate is pressed between two flat platens until the stop blocks ceased further travel. Upon removal of the load, the laminates are conditioned for approximately 24 hrs before being re-measured for final thickness. The thickness of each foam laminate measured before and after pressing is listed in Table 3.

Square samples measuring 305mm (12 in) of each laminate are prepared using a band saw for shaping. The samples are shaped on a 15 ton Carver hydraulic press. The foam laminates are shaped with a shaped tool FIG. 7which imparts a repeating ribbed shape. The mold half comprising the shape is mounted to the stationary platen of the press. The hydraulic pump speed is programmed to a level of 50 percent, the pump force was programmed to 111,210 N (25,000 pounds) and the dwell time was set to 5 seconds. The foam laminates are shaped at ambient temperature. Prior to forming, two steel stop blocks measuring 74.86mm in height are placed on the movable (e.g., lower) platen along side the foam laminate. Photographs of Examples 1 and 2 and A and B pressed with the shaped tool are shown in FIG. 8 to FIG. 11.

All four shaped laminates are conditioned at 23°C and 50 percent relative humidity for about 24 hours. Then laminate thickness as well as the resulting thickness of each layer is then measured using digital calipers. Compression set is computed in accordance with the following equation:

Compression Set ( ) = 100-At/t_o

whereby t₀ is layer 1 thickness before forming and At is the change in layer 1 thickness (e.g.

Thickness_Before - Thickness_Af_ter)- The thermal resistance (e.g., R-value) of non-pressed foam laminates and shaped foam laminates is then measured in accordance with ASTM C518-04.

Compression set and R-value for shaped Examples 1 and 2 and shaped Comparative Examples A and B are listed in Table 4.

Table 4

As can be seen by the data in Table 4 and from FIG. 8 to FIG. 9 the foam laminates of the present invention provide a good balance of shapability, shape retention, and thermal resistance.

Example 1 is further shaped with a cedar shake tool, FIG. 13.

Claims

CLAIMS:

1. A method to prepare a shaped foam laminate article comprising a first foam layer and a second foam layer comprising the steps of:

(A) preparing a foam laminate by the steps comprising:

(i.a) extruding a first thermoplastic polymer composition with a blowing agent to form a first thermoplastic polymer foam plank, the first foam plank having a thickness, a top surface, and a bottom surface in which said surfaces lie in the plane defined by the direction of extrusion and the width of the first foam plank, wherein the first foam plank has a vertical compressive balance equal to or greater than 0.4 and an internal cell gas pressure less than 1 atmosphere and

and

(iii) bonding the second surface of the first foam blank to a surface of the second foam plank to form a foam laminate,

and

(B) providing shape to the first foam layer of the foam laminate by:

(i) contacting the pressing surface of the first foam layer with a mold and

(ii) pressing the pressing surface of the first foam layer such that a shaped foam laminate article is formed.

2. A method to prepare a shaped foam laminate article comprising a first foam layer and a second foam layer comprising the steps of:

(i) preparing a first foam layer by the steps comprising:

and

(iii) providing shape to the first foam layer by:

(iii.a) contacting the pressing surface of the first foam layer with a mold and

and

(iv) bonding the second surface of the shaped first foam layer to a surface of the second foam layer to form a shaped foam laminate.

3. The method of Claims 1 or 2 wherein the second foam layer has an R-value per inch greater than the R-value per inch of the first foam layer.

4. The method of Claims 1 or 2 wherein the first foam comprises a first thermoplastic polymer and the second foam comprises a second thermoplastic polymer.

5. The method of Claims 1 or 2 wherein the first foam is a thermoplastic polymer and the second foam is a thermoset polymer.

6. The method of Claims 1 or 2 wherein the blowing agent used in preparing the first foam layer is a chemical blowing agent, an inorganic gas, an organic blowing agent, or combinations thereof.

7. The method of Claims 1 or 2 wherein the first foam is a thermoplastic polymer comprising a styrene polymer, a styrene and acrylonitrile copolymer, or mixtures thereof and the blowing agent is carbon dioxide, water or a combination thereof.

8. The method of Claims 1 or 2 wherein the second foam is a styrene polymer, a styrene and acrylonitrile copolymer, a mixture of a styrene and acrylonitrile copolymer, an epoxy polymer, a phenolic polymer, an urea-formaldehyde polymer, a polyisocyanurate polymer, or a polyurethane polymer.

9. The method of Claims 1 or 2 wherein the first foam layer is bonded to the second foam layer by thermal means, mechanical means, physical means, chemical means, adhesive means, or combinations thereof.

10. The methods of Claims 1 or 2 wherein the shaped foam laminate article is a roof tile, an exterior facade panel, a hydronic floor heating insulation panel, a basement foundation panel, a shutter, an external coving, a baluster, a pillar, a roller shutter box, a thermal bridge breaker, a door, a door panel, a door frame, a window frame, a pipe shell, a pipe elbow, a pipe T-shape, a pipe connection box, or a partition wall panel.

11. A shaped foam laminate article made by the method of Claims 1 or 2.