EP0412889A1 - Prefabricated watertight acrylic material and its use in roof and sub-roof coverings - Google Patents

Abstract

Prefabricated acrylic waterproof material made as a multilayer sheet, comprising a layer of textile backing, a layer of a foam made from an acrylic polymeric material and a layer of a binder made from an acrylic polymer material, characterised in that each layer is bound to at least one of the other two layers in such a way that the foam layer is always in contact with the textile backing layer, the thicknesses of the various layers of the multilayer sheet correspond to the surface densities of the said layers, ranging from 30 to 300 g/m<2> for the textile backing layer, from 10 to 100 g/m<2> for the foam layer and from 50 to 2000 g/m<2> for the binder layer.

Description

The invention relates to a prefabricated acrylic sealing material in a multilayer sheet and also relates to the application of this material to the sealing of blankets and undercoverings.

Various prefabricated waterproofing materials have already been proposed in multilayer sheets for the waterproofing of building roofs and in particular of flat roofs. Thus, patent FR-A-1,483,973 describes a waterproof cover element, which consists of a sheet consisting of a plastic or elastic waterproofing membrane laminated to a flexible sheet of open-cell honeycomb foam, said element being applied by gluing on the foam side, using an appropriate glue, on the support which is to be sealed. Patent FR-A-2,362,981 relates, inter alia, to an acrylic sealing material formed from a layer of a textile material coated, on one of its faces, with a waterproof layer of an acrylic polymeric material, said sealing material being applied by adhesive bonding on the textile side, using an appropriate adhesive, on the support which is to receive the seal, so that a central part of the textile layer is neither impregnated nor by the adhesive used for bonding, or by the acrylic polymeric material of the impermeable layer.

Also known (FR-A-2,467,934 and FR-A-2,517,726) is an impact-resistant roofing material, waterproof and permeable to air and vapor, for elemental roofs. discrete such as tiles or slates overlapping each other, said material consisting of a nonwoven web of fibers of a polymer material such as polypropylene, polyethylene, polyester, vinyl polymer, hot coated, on one side (FE- A-2,467,934) or on both sides (FR-A-2,517,726), of a film of fillerized bitumen in an amount just sufficient to present on cooling a micro-hole or micro-cracked structure, opposing the passage of liquid through capillarity, but allowing the passage of air or vapor.

Despite their interesting performance, the prefabricated waterproofing materials in multilayer sheets offered either for the waterproofing of building roofs or as under-roofing or under-roofing materials still have certain shortcomings. In particular, the material described in patent FR-A-1,483,973 has a low resistance to static puncture, determined according to standard NF P 84352, and in addition the open cells of the foam constitute a serious defect in the event of leakage ( sponge effect and accumulation of large amounts of water). For the bituminous roofing material of the patents FR-A-2,467,934 and FR-A-2,517,726, the well-known sensitivity of the bitumen to ultraviolet rays imposes an implementation of the covering without delay, the product losing also part of its flexibility in cold periods.

The invention provides a prefabricated acrylic sealing material in the form of a multilayer sheet, which can be used for sealing building roofs or also as under-roofing or under-roofing material and which in each said applications overcomes the shortcomings of sheet materials used so far.

The prefabricated acrylic sealing material according to the invention consists of a multilayer sheet comprising a layer of a textile support, a layer of a foam of an acrylic polymeric material. and a layer of a binder in an acrylic polymer material, and is characterized in that each layer is bonded to at least one of the other two layers so that the foam layer is always in contact with the support layer textile, the thicknesses of the various layers corresponding to the surface masses of these layers ranging from 30 to 300 g / m² for the textile support layer, from 10 to 100 g / m² for the foam layer and from 50 to 2000 g / m² for the binder layer.

The textile support layer may consist of a woven or, preferably, nonwoven web of natural or synthetic organic fibers, for example fibers of a polymer material such as polypropylene, polyethylene, polyamide and in particular aromatic polyamide, polyester, vinyl polymer, or even inorganic fibers, for example glass fibers.

The acrylic polymeric material used to form the foam layer is based on at least one polymer chosen from homopolymers of acrylic esters, copolymers of acrylic esters with one another and copolymers of one or more acrylic esters with a quantity minority of one or more ethylenically unsaturated monomers such as ethylenically unsaturated carboxylic acids and their anhydrous, in particular acrylic acid, methacrylic acid, maleic anhydride, crosslinking monomers such as acrylic amides, for example acrylamide, methylolacrylamide, vinylaromatic monomers such as styrene, said copolymers possibly being random copolymers, graft copolymers or even block copolymers. The acrylic esters which form part of the composition of the abovementioned polymers are advantageously acrylates or alkyl methacrylates, including the C radical to C₁₈ and preferably C₂ to C₈ alkyl radical, in particular ethyl, butyl, hexyl, 2-ethylhexyl, and may optionally carry at least one functional group, for example a hydroxyl or amino group.

The polymeric material from which the binder layer is formed is based on at least one acrylic polymer chosen from homopolymers and copolymers defined above as capable of constituting the foam layer.

The polymer or polymers constituting the polymer material of the binder layer may be identical or partially identical to the polymers forming the polymeric material of the foam layer or, on the contrary, different from these latter polymers.

In addition to its polymer component, each of the foam and binder layers may also contain various additives, for example fillers such as kaolin and calcium carbonate, pigments, dyes, repellents, wetting agents, fungicides, algicides, said additives being associated with the polymer component of the layer concerned in amounts corresponding to those usually recommended for their use.

Advantageously, the binder layer of the multilayer sheet constituting the sealing material contains a few percent, for example 2 to 5%, by weight of a granular filler, in particular glass microbeads, silicate, calcium carbonate, the size of which grains is about 150 µm to 600 µm, which gives a surface micro-roughness to the binder layer.

According to a first embodiment, the sealing material according to the invention has its foam layer interposed between its textile support layer and its binder layer, the thicknesses of said layers corresponding to surface masses ranging from 30 to 300 g / m² for the textile support layer, from 10 to 100 g / m² for the foam layer and from 1000 to 2000 g / m² for the binder layer. In particular, in this first embodiment, the foam layer has a cellular gradient from the textile layer to the binder layer, that is to say has a decreasing number of cells, starting from the layer textile, as one approaches the binder layer to arrive, in contact with said binder layer, at a continuous and closed surface. The multilayer sheet sealing material obtained according to the first above-mentioned embodiment can be used to seal roofs, in particular flat roofs, such a material having total water resistance, good resistance to ultraviolet light, excellent resistance to high temperature (in particular, no creep up to about 120-130 ° C) and good flexibility at very low temperature (no breakage by bending on a 10 mm diameter mandrel at -35 ° C.). The installation of said sealing material on the support intended to receive it is carried out by gluing, on the textile side of the material facing the support, by means of any suitable adhesive, for example acrylic adhesive in aqueous dispersion or in the form of a solution. in a solvent, covering the free edge of a sheet that has just been laid by about 10 cm from the adjacent sheet being laid.

To improve the joining of the adjacent sealing sheets during the above-mentioned laying, a marginal zone of the textile support layer extending along a longitudinal edge of the sealing sheet can be replaced by a layer of substantially equal thickness, of a thermally activatable adhesive, for example hot-melt adhesive (in English "hot melt"), the width of said zone ranging for example from 5 to 10 cm. When performing the sealing of the cover, the connection between two adjacent sealing sheets is then carried out by covering the free longitudinal edge of the sealing sheet which has just been laid by the zone of thermally activatable adhesive of the textile support layer of the sealing sheet during installation, after activating, by heating, the adhesive of said zone.

According to a second zone for producing the sealing material according to the invention, the thicknesses of the layers constituting the multilayer sheet correspond to surface masses ranging from 30 to 300 g / m² for the textile support layer, from 10 to 100 g / m² for the foam layer and 50 to 500 g / m² for the binder layer, said layers being arranged so that the foam layer is interposed between the textile support layer and the binder layer or else the layer of textile support is disposed between the foam layer and the binder layer.

The sealing material obtained according to the second embodiment can be used as under-roofing material (such as under-roofing), such a material having total water tightness under a pressure of 1500 Pa and a high vapor permeance. of water (at least 100 g per m² and per 24 hours according to standard NF T 30-018), having good resistance to natural aging and good UV resistance, resistant to falling objects or people and offering , if desired, an anti-slip surface.

The sealing sheets constituting the sub-roofing material or under-coverings are placed between the support of the tiles or slates and the frame, side binder layer facing the tiles or slates, so that their longitudinal edges are substantially oriented. along the line of greatest slope of the roof and that the free longitudinal edge of the sheet just laid is covered by about 10 to 20 cm of the textile support layer or the foam layer, as the case may be, of the adjacent sheet during installation.

The multilayer sheet sealing material according to the invention can be manufactured by any method making it possible to produce a sheet having the three-layer structure characteristic of the invention. Advantageously, the sheet according to the invention is produced by a coating technique implemented in a conventional manner and comprising a coating of textile support chosen by means of a precursor of the foam layer, said precursor consisting of a drying operation. of the foam layer, then a coating, as the case may be, of the free surface of the dried foam layer or of the free surface of the textile support layer by means of a precursor of the binder layer, said precursor being formed of an acrylic composition in aqueous dispersion, and finally drying of the binder layer.

The marginal zone of thermally activatable adhesive can be formed along a longitudinal edge of the textile support layer of the sealing sheet can be achieved by abrading the protective layer. textile and extrusion of the adhesive on the site thus formed by abrasion of the textile.

The acrylic foaming composition in aqueous dispersion, which forms the precursor of the foam layer, is prepared, in a conventional manner, by first producing an aqueous dispersion of the ingredients, namely acrylic polymeric material and various additives, chosen to constitute the composition, then subjecting said dispersion to sufficient mechanical stirring to bring the dispersion in the form of a foam.

Similarly, the aqueous dispersion of acrylic binder, which forms the precursor of the binder layer, is carried out by conventional techniques of dispersion, in an aqueous phase, of the ingredients, namely acrylic polymer material and various additives, chosen to constitute the binder acrylic.

The various operations, namely dispersion, coating, drying, abrasion of the textile layer, extrusion of the thermally activatable adhesive, which is encountered in the manufacture of the sealing sheet, can be carried out using various devices. known for this purpose.

The invention is illustrated by the following examples given without limitation.

Example 1:

By operating by coating, two series A and B were made of sealing sheets according to the invention which can be used as roofing material.

Series A:

The sealing sheets of this series consisted of a nonwoven web of polypropylene fibers of equal surface mass. at 110 g / m² coated on one side with a layer of acrylic foam based on a terpolymer of ethyl acrylate, acrylic acid and N-methylolacrylamide, the said layer of foam having a surface mass of 50 g / m², and coated on its other face with a layer of an acrylic binder based on a copolymer of ethyl acrylate and methyl methacrylate and charged, depending on the case, from 2 to 5%, by weight of the binder, glass or silicate microspheres having a diameter of approximately 300 μm, said layer of binder having a surface mass of 300 g / m².

Series B:

The sealing sheets of this series consisted of a sheet of a nonwoven of polyester fibers having a surface mass of 130 g / m² coated on one side with an acrylic foam based on the terpolymer used to prepare the sheets. of series A, said layer of foam having a surface mass of 20 g / m² and being coated in turn with a layer of an acrylic binder based on a copolymer of ethyl acrylate and methyl methacrylate and loaded, depending on the case, from 2 to 5%, by weight of the binder, of calcium carbonate grains having a particle size ranging from 200 to 500 μm, said layer of binder having a surface mass of 300 g / m².

The sealing sheets thus produced are completely watertight under a pressure of 1500 Pa and have a water vapor permeance, according to NF T 30-018, of approximately 100 to 110 g per m² and per 24 hours. They also have good UV resistance and good fire resistance and also offer a satisfactory non-slip surface (free surface of the binder layer).

Example 2;

By operating by coating, two series C and D were made of waterproofing sheets according to the invention which can be used for waterproofing roofs (flat roofs).

Series C:

The sealing sheets of this series consisted of a sheet of a nonwoven of polyester fibers having a surface mass of 150 g / m² coated on one side with an acrylic layer based on the terpolymer used in the example. 1, said layer of foam having a surface mass of 50 g / m² and being coated in turn with a layer of an acrylic binder based on a copolymer of butyl acrylate and methyl methacrylate in admixture with a copolymer of butyl acrylate and styrene at 20% by weight of styrene and charged, depending on the case, from 2 to 5%, by weight of the binder, of glass or silicate microspheres having a diameter of approximately 300 μm, said binder layer having a surface mass of 1700 g / m².

Series D:

The sealing sheets of this series consisted of a sheet of nonwoven of polypropylene fibers having a surface mass of 136 g / m² coated on one side with a layer of acrylic foam based on the terpolymer used. in Example 1, said layer of foam having a surface mass of 20 g / m² and being in turn coated with a layer of thermally crosslinked acrylic binder based on a terpolymer of butyl acrylate, methyl methacrylate and of N-methylolacrylamide, said binder layer having a surface mass of 1700 g / m². Each sheet also had a coating of hot-melt adhesive on a marginal zone of 5 to 10 cm formed, by abrasion of the nonwoven layer, along a longitudinal edge of the sheet, this zone provided with hot-melt adhesive. being intended to facilitate the junction of the adjacent sealing sheets (joint lé à lé).

The waterproofing sheets for covers of series C and D are completely waterproof against a pressure of 0.6 MPa. They also have excellent UV resistance, good creep resistance (creep temperature above 120 ° C) and good flexibility at low temperature (no breakage by bending on a mandrel with a diameter of 10 mm at - 35 ° C). In addition, the sheets of the C series, which contain a granular load on the surface of the binder layer, also offer a satisfactory anti-slip surface.

Of course, the invention is not limited to the embodiments described, but on the contrary encompasses the various variants which the specialist can define while remaining within the scope of the invention.

Claims (13)

1 - Prefabricated acrylic sealing material in multilayer sheet, comprising a layer of a textile support, a layer of a foam made of an acrylic polymeric material and a layer of a binder made of an acrylic polymeric material, characterized in that each layer is bonded to at least one of the other two layers so that the foam layer is always in contact with the textile support layer, the thicknesses of the different layers of the multilayer sheet correspond to the surface masses of said layers ranging from 30 to 300 g / m² for the textile support layer, 10 to 100 g / m² for the foam layer and 50 to 2000 g / m² for the binder layer. 2 - Material according to claim 1, characterized in that the textile support layer consists of a woven or, preferably, nonwoven web of natural or synthetic organic fibers, for example fibers made of a polymer material such as polypropylene, polyethylene, polyamide and in particular aromatic polyamide, polyester, vinyl polymer, or inorganic fibers, for example glass fibers. 3 - Material according to one of claims 1 or 2, characterized in that the polymeric material used to form the foam layer and the polymeric material of the binder tick are each based on at least one polymer chosen from homopolymers of acrylic esters, the copolymers of acrylic esters with one another and the copolymers of one or more acrylic esters with a minority amount of one or more ethylenically unsaturated monomers such as ethylenically unsaturated carboxylic acids and their anhydrides, in particular acrylic acid, methacrylic acid, maleic anhydride, crosslinking monomers, in particular acrylamide and methylolacrylamide, and vinylaromatic monomers such as styrene. 4. - Material according to claim 3, characterized in that the acrylic esters used in the composition of the homopolymers and copolymers are chosen from alkyl acrylates and methacrylates, the alkyl radical of which is C₁ to C₁₈ and preferably C₂ to C₈ and may optionally carry a functional group, in particular a hydroxyl or amino group. 5 - Material according to any one of claims 1 to 4, characterized in that in addition to its polymer component, each of the foam and binder layers contains additives, in particular fillers, pigments, dyes, wetting agents, fungicides, algicides and flame retardants. 6 - Material according to any one of claims 1 to 5, characterized in that the binder layer of the multilayer sheet contains a few percent, especially 2 to 5%, by weight of a granular filler, for example glass microbeads or silicate, calcium carbonate, the grain size of which is approximately 150 μm to 600 μm, to impart a surface microroughness to the binder layer. 7 - Material according to any one of claims 1 to 6, characterized in that the foam layer is interposed between the textile support layer and the binder layer and in that the thicknesses of said layers correspond to surface masses ranging from 30 to 300 g / m² for the textile support layer, 10 to 100 g / m² for the foam layer and 1000 to 2000 g / m² for the binder layer. 8 - Material according to claim 7, characterized in that the foam layer has a cellular gradient from the textile support layer to the binder layer, that is to say has a decreasing number of cells, to starting from the textile support layer, as one approaches the binder layer to arrive, in contact with said binder layer, on a continuous and closed surface. 9 - Material according to one of claims 7 or 8, characterized in that a marginal zone of the textile support layer extending along a longitudinal edge of the multilayer sheet is replaced by a layer, of substantially equal thickness, of a thermally activatable adhesive. 10 - Material according to any one of claims 1 to 6, characterized in that the thicknesses of the layers constituting the multilayer sheet correspond to the surface masses of said layers ranging from 30 to 300 g / m² for the textile support layer, from 10 at 100 g / m² for the foam layer and from 50 to 500 g / m² for the binder layer, said layers being arranged so that the foam layer is interposed between the textile support layer and the binder layer or although the textile support layer is disposed between the foam layer and the binder layer. 11 - Application of the material according to any one of claims 1 to 10 in sealing of covers or under-covers. 12 - Application according to claim 11, wherein a sealing of covers is made using the material according to one of claims 8 to 9. 13 - Application according to claim 11, wherein the material according to claim 10 is used as the material of under-covers.