WO2012092019A1

WO2012092019A1 - Waterproofing membrane

Info

Publication number: WO2012092019A1
Application number: PCT/US2011/066120
Authority: WO
Inventors: Robert A. Wiercinski; Anandakumar Ranganathan
Original assignee: W.R. Grace & Co.-Conn.
Priority date: 2010-12-29
Filing date: 2011-12-20
Publication date: 2012-07-05

Abstract

Disclosed is a waterproofing membrane that comprises a carrier sheet, a pressure sensitive adhesive layer on one surface of the carrier sheet, and a protective coating layer on the adhesive layer. The protective coating layer comprises a vinyl acetate copolymer (i.e., a copolymer of vinyl acetate and a comonomer) having a Tg of 10°C to 35°C. The protective coating layer protects the membrane against weather exposure, tolerates foot traffic and strongly adheres to concrete cast against it.

Description

Waterproofing Membrane

Field of the Invention

[0001] The present invention relates to a pre-applied waterproofing membrane that will adhere to concrete applied against its surface.

Background of the Invention

[0002] Sheet-like waterproofing membrane laminates are well-known for application to concrete and other substrates. These laminates typically comprise a carrier sheet and a pressure sensitive adhesive layer. In many applications, the waterproofing sheet material is applied to a concrete substrate that has already been formed, such as a building foundation. In such a case, the adhesive layer of the membrane is applied against the cured concrete surface. In another technique, the waterproofing membrane is affixed to the concrete form or lagging with the carrier sheet against the lagging and the adhesive portion facing toward the cavity in which the concrete is poured. The adhesive portion of the membrane will adhere to the freshly poured concrete, thus providing a fully adhered waterproofing membrane on the cured concrete surface after the lagging is removed. This technique is sometimes referred to as "blind side" (or pre-applied)

waterproofing. A similar process may be used on horizontal surfaces where the membrane is applied to compacted soil or gravel or to a concrete slab, with the adhesive portion facing upward, then casting concrete against the membrane.

[0003] In addition to the carrier sheet and pressure sensitive adhesive layer, typical commercial waterproofing membranes include a removable release sheet that is used to prevent the adhesive portion of the membrane from adhering to the carrier sheet or other portion of the membrane when the membrane is rolled up. This release sheet must be removed from the membrane prior to or during installation and disposed in the trash, thus creating environmental waste.

[0004] US 3,900,102 (Hurst) discloses one such membrane comprising a polyethylene support sheet, a bituminous adhesive and a releasable

siliconized paper for protecting the adhesive. The release paper is removed as the membrane is unrolled and adhered to a building substrate (see Hurst Fig. 4). US 4,751,122 (May) discloses a membrane laminate that includes a sheet-like paper substrate with a release coating (e.g., silicone) on one face and a waterproofing pressure sensitive adhesive on the other face. This membrane also includes a removable strip along the edge which, when removed, permits overlapping seams to adhere. US 4,172,830 (Rosenberg) and US 4,215,160 (Rosenberg) disclose paperless membrane laminates that include a silicone release coating on the outer surface of the carrier sheet to prevent the adhesive layer from adhering to the carrier sheet when the membrane is rolled up. US 5,254,661 (Wilson) discloses a similar type of paperless membrane laminate in which the release coating is a water-based silicone emulsion. During installation, edge portions of the release coating may be removed by wet abrasion to permit adhesion of overlap seams of adjacent membranes.

[0005] US 4,994,328 (Cogliano) discloses a waterproofing membrane capable of adhering to freshly poured concrete (i.e., blind-side or pre-applied waterproofing). The membrane has a bituminous adhesive layer that is coated with a non-tacky, water-insoluble polymeric coating such as, for example, a polyvinyl alcohol, silica, and glycerin mixture in a weight ratio of 1:10:0.5. The coating purportedly protects the adhesive layer while

permitting a strong adhesive bond to freshly poured concrete. However, the coating can be slippery when wet and, thus, not suitable for foot traffic.

US 5,316,848 (Bartlett) discloses a similar blind-side waterproofing

membrane that includes a carrier layer, a pressure sensitive adhesive layer, and a protective coating on the adhesive layer, wherein the coating may be selected from various types of polymers, preferably an acrylic-based elastomer, such as styrene butyl acrylate. US 5,496,615 (Bartlett) discloses a similar membrane laminate where the protective coating has a finely divided particulate material, such as sand, calcium carbonate, cement, titanium dioxide, etc., dusted thereon. [0006] US 6,500,520 (Wiercinski) discloses a membrane laminate having a carrier support sheet, an adhesive layer, and embedded on the adhesive layer a layer of granulated inorganic particulates capable of reacting with concrete, such as aluminum oxide trihydrate, silica dioxide, fly ash, blast furnace slag, alkali or alkaline earth metal salts, etc. The particles may be attached to the adhesive layer using a water-soluble material such as ethylene vinyl acetate or polyvinyl alcohol.

[0007] WO 2010/048198 (Wiercinski) discloses a membrane laminate comprising four layers: a carrier sheet, a waterproofing adhesive layer, a protective coating layer containing inorganic particulates and a weatherable elastomer, and a releasable bonding material. The releasable bonding material may be a water soluble polymer (e.g., PVOH), an alkali soluble polymer (e.g., copolymer of styrene and maleic anhydride), or a homopolymer or copolymer of polyvinyl acetate. Typically, the releasable bonding material layer has a thickness (dry) of about 0.1 to 20 μηι. [0008] Typical commercial waterproofing membranes used for blind-side (or pre-applied) applications include a release sheet and unroll wrong side up with the adhesive portion facing downward. This forces the installer to first unroll then flip over a large, unwieldy membrane prior to installing it.

Alternatively, two installers are needed to lift the heavy roll so that it may be unrolled with the correct side facing upward.

[0009] It would be advantageous to provide a waterproofing membrane that binds strongly to concrete cast against its surface. In addition, it would be advantageous to provide a waterproofing membrane that has an outer surface that will tolerate foot traffic and weather, while protecting the adhesive layer against the damaging effects of UV and heat exposure. It would also be advantageous to provide a waterproofing membrane that does not require a release sheet that must be removed at the job site.

Summary of the Invention

[0010] The present invention embraces a waterproofing membrane in the form of a sheet-like laminate that comprises a carrier sheet, a pressure sensitive adhesive layer on one surface of the carrier sheet, and a protective coating layer on the adhesive layer. The protective coating layer comprises a vinyl acetate copolymer (i.e., a copolymer of vinyl acetate and a comonomer) having a Tg (glass transition temperature) of 10°C to 35°C. The

waterproofing membrane also may optionally include a removable release sheet on the protective coating layer to prevent the membrane from adhering to itself when rolled up. The protective coating layer protects the membrane against weather exposure, tolerates foot traffic and strongly adheres to concrete cast against it.

[0011] The present invention also embraces a method of waterproofing a concrete structure by applying a waterproofing membrane as defined herein to a building substrate or concrete form with the protective coating layer of the membrane facing the area into which the concrete will be cast, and casting concrete such that it contacts the protective coating layer of the membrane.

Brief Description of the Drawings

[0012] Fig. 1 depicts a cross-section of a waterproofing membrane of the present invention.

Detailed Description of the Invention

[0013] One embodiment of the waterproofing membrane of the present invention is depicted in Fig. 1, which shows a cross-section of the membrane taken along the width of the membrane. Typical commercial membranes are in the form of a sheet-like laminate with a width in the range of about 30 to 185 cm, more typically about 60 to 140 cm, preferably about 80 to 130 cm, and a length of about 5 to 60 m, more typically about 15 to 36 m, and are rolled up into a roll. These membranes generally have a thickness of about 0.15 mm to about 5 mm, more typically about 0.25 mm to about 2.5 mm, preferably about 0.25 mm to about 1.8 mm.

[0014] As shown in Fig. 1, the waterproofing membrane comprises at least three laminated layers, and preferably consists essentially of three laminated layers. The first layer is a carrier sheet 2 and the second layer is an adhesive layer 4, which is adhered to one surface (i.e., a first surface) of the carrier sheet. The third layer of the waterproofing membrane is a protective coating layer 6 on the adhesive layer 4 (i.e., on the exposed surface of the adhesive layer opposite that which abuts the carrier sheet). Optionally, the

waterproofing membrane may include a removable release sheet (not shown) on the protective coating layer 6. As depicted, the protective coating layer 6 is on the surface of the adhesive layer 4 that is opposite the surface of the adhesive layer that is adhered to the carrier sheet 2. The waterproofing membrane may optionally include additional layers of material on either face of the carrier sheet as desired. For example, a second adhesive layer may be adhered to the other surface (i.e., a second surface opposite the first surface) of the carrier sheet (e.g., to enable the membrane to be adhered to a

substrate). The adhesive layer 4 is adhered either directly onto a surface of the carrier sheet, or indirectly if there is an optional additional layer of material interposed between the carrier sheet 2 and the adhesive layer 4. The protective coating layer 6 may optionally include a coating or dusting of finely divided inorganic particulate material, such as sand or calcium carbonate, on its outer exposed surface.

[0015] The carrier sheet 2 provides mechanical strength and waterproofing integrity for the membrane. The carrier sheet typically will have a thickness of about 0.05 to 2.0 mm, preferably about 0.3 to 1.0 mm, and should comprise a generally smooth surface, such as is provided by films, sheets, fabrics, and extrusion coated woven and non-woven fabrics. Suitable materials for films and extrusion coatings include polypropylene, polyethylene, ethylene- propylene copolymers, ethylene-olefin copolymers, ethylene-vinyl acetate copolymers, polyvinyl acetate, polyethyl acrylate, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyamides and combinations thereof. Polyethylene and polypropylene are preferred. A preferred carrier sheet comprises a thermoplastic film of high density polyethylene (HDPE). Fabrics may be woven or non- woven and may comprise polyethylene, polypropylene, polyethylene terephthalate and poly amide. A woven polypropylene fabric is particularly suitable. [0016] If the membrane comprises an optional release liner, the carrier will usually be surface treated to increase surface tension to enhance adhesion. Generally, the carrier sheet is not surface treated to increase the surface tension if the membrane does not comprise a release liner. However, in some cases it may be desirable to treat the surface of the carrier sheet on which the adhesive will be applied in order to enhance adhesion of the adhesive to the carrier sheet. One such surface treatment option is corona treatment.

Preferably, the carrier sheet will not be corona treated, particularly the surface of the carrier sheet that comes in contact with the protective coating layer 6 when the membrane is rolled up. [0017] Additives may be incorporated into the carrier material to reduce surface tension. These may be incorporated into the bulk of the material in a separate compounding step. The additives may also be incorporated into the bulk of the material during the melt extrusion process to produce a sheet, film, or extrusion coated fabric. [0018] The adhesive layer 4 may comprise a non-bituminous pressure sensitive adhesive or a rubber modified bitumen pressure sensitive adhesive. A membrane wherein the adhesive layer comprises a modified bitumen pressure sensitive adhesive may be especially preferred. The adhesive layer typically will have a thickness of about 0.05 to 2.5 mm, preferably about 0.07 to 2.0 mm, more preferably about 0.1 to 1.0 mm, most preferably about 0.13 to 0.8 mm. [0019] Suitable non-bituminous, or synthetic, pressure sensitive adhesives include butyl rubber based adhesives, polyisobutylene based adhesives, butyl based adhesives, acrylic based adhesives, vinyl ether based adhesives, styrene-isoprene-styrene (SIS) based adhesives, styrene-ethylene-butylene- styrene (SEBS) based adhesives, styrene-butadiene-styrene (SBS) based adhesives, styrene-butadiene rubber (SBR) based adhesives, and

combinations thereof. Preferably, the synthetic adhesive is a pressure sensitive hot melt adhesive block copolymer of SIS, SBS or SEBS, most preferably SIS block copolymer. For a more detailed description of pressure sensitive adhesives, see Satas, Handbook Of Pressure Sensitive Adhesive Technology, by Van Nostrand Reinhold Company, Inc. (1982), incorporated herein by reference. Other rubbers include polyisoprene, polybutadiene, natural rubber, polychloroprene rubber, ethylene-propylene rubber, ethylene alpha olefin, nitrile rubbers, and acrylic rubber.

[0020] Other suitable non-bituminous synthetic pressure sensitive adhesives may comprise amorphous polyolefins. Amorphous polyolefin (APO) is defined as polyolefin with a degree of crystallinity of less than 30% as measured by differential scanning calorimetry. These polymers can be either homopolymers of propylene or copolymers of propylene with one or more ct- olefin comonomer, such as, for example, ethylene, 1-butene, 1-hexene, 1- octene and 1-decene. The APO polymers of the types herein described above are commercially available from Eastman Chemical Company, Kingsport, Tennessee, under the trade name designation Eastoflex or from Huntsman Corporation, Houston, Texas, under the trade name designation Rextac or from Degussa Corporation, Parsipanny, New Jersey, under the trade name designation Vestoplast. Like rubber based adhesives, these are also combined with a tackifier and plasticizer to produce a pressure sensitive adhesive. See Eastman bulletin "Pressure-Sensitive Adhesives Based on Amorphous Polyolefin From Eastman Chemical Company" [0021] Hot melt adhesives based on amorphous polyolefins are suitable as well. In comparison to pressure sensitive adhesives these are not tacky and generally comprise only APO, tackifier, and polyolefin wax. Refer to Eastman brochure "Formulating Hot Melt Adhesives Based on Epolene Polymers." Hot melt adhesives based on ethylene vinyl acetate are also suitable. See

"DuPont Elvax for Adhesives, Sealants, and Wax Blends."

[0022] The non-bituminous or synthetic pressure sensitive adhesive can optionally contain typical additives, such as light absorbers (e.g., carbon black, benzotriazoles, hydroxyphenyl-triazine, benzophenones, etc.), light stabilizers (e.g., hindered amines), antioxidants (e.g., hindered phenols), fillers (e.g., calcium carbonate, silica, titanium dioxide, etc.), plasticizers, rheological additives, and mixtures thereof. Preferred synthetic adhesives contain light absorbers, light stabilizers, and antioxidants.

[0023] A rubber modified bitumen pressure sensitive adhesive may also be used, and may be preferred for certain applications. All of the rubbers listed above (e.g., SIS, SBS, SEBS, SBR, etc.) may be blended with bitumen to produce a pressure sensitive adhesive. The rubber modified bitumen may also typically include a processing oil such as an aromatic, naphthenic or paraffinic oil. For unfilled adhesives, the wt. % rubber is about 10% to 22%; the wt. % bitumen is about 43% to 90%; and the wt. % processing oil is about 0% to 35%. The pressure sensitive adhesive may also comprise an inorganic filler such as silica, calcium carbonate, talc, or clay. If present, the wt. % filler may be about 0% to 50% of the total.

[0024] Generally, for improved adhesion to post cast concrete it is preferred that the pressure sensitive adhesive has a penetration greater than about 30 decimillimeters (dmm) (150 g, 5 sec, 70° F.) as measured according to ASTM D 5-73, incorporated herein by reference.

[0025] The protective coating layer 6 has several functions. It protects the membrane against exposure to weather, particularly UV and heat, it tolerates foot traffic, and, most importantly, it operates to bond to concrete cast against it. Furthermore the protective coating is resistant to oil absorption. The protective coating will absorb little or no oils from a rubber modified bitumen pressure sensitive adhesive. The bituminous oils are dark in color and would reduce the reflectivity of the protective coating if it were not resistant to oil absorption. A highly reflective coating is advantageous because it resists deterioration when exposed to sunlight versus a less reflective coating. As a result, concrete cast against a highly reflective membrane that has been exposed to sunlight will bond well to the membrane. The protective coating layer can also prevent the membrane from adhering to itself when the membrane is rolled up, thus making it possible to dispense with the need for a release liner. [0026] The protective coating layer consists essentially of a vinyl acetate copolymer (i.e., a copolymer of vinyl acetate with a comonomer), wherein the vinyl acetate copolymer has a Tg of 10°C to 35°C. The term "consists essentially of means that the protective coating layer contains either no other polymer components or contains only insubstantial quantities of other polymer components that do not substantially alter the properties of the vinyl acetate copolymer. Tg is measured via differential scanning calorimetry at a heating rate of 20°C/min. The weight average molecular weight of the copolymer is typically 30,000 to 500,000.

[0027] A suitable comonomer for the vinyl acetate copolymer may be selected from a monomer whose homopolymer would have a Tg < 20°C, and preferably < 0°C. The wt. % of vinyl acetate and wt. % of comonomer in the copolymer may be adjusted to provide a copolymer with a Tg within the range of 10°C to 35°C. Comonomers may include vinyl alkanoic acid esters (wherein the alkanoic acid has from 8-18, preferably 10-14, carbon atoms, such as, for example, vinyl laurate (vinyl dodecanoate) and vinyl versatate (vinyl neo- decanoate), a C3 to C10 alpha olefin, and acrylic esters of lower alkanols, such as ethyl, propyl, butyl, and ethylhexyl acrylate. Copolymers of vinyl acetate and vinyl laurate are preferred. Copolymers of vinyl acetate and vinyl laurate are available from Wacker, under the tradename Vinnapas®. One such product is Vinnapas® B500/VL20 comprising 20% vinyl laurate. This copolymer has a glass transition temperature of 21°C. It has a penetration of 4 dmm according to ASTM D5 (5 sec, 150g load). The weight average molecular weight is 125,000 to 175,000 (according to Wacker data sheet).

[0028] The vinyl acetate copolymer should preferably not include any surfactant, which can reduce the ability of the protective coating layer to adhere to the adhesive layer and, thus, negatively affect the membrane's water immersion resistance. It is important that the protective coating layer remain well adhered to the adhesive layer after water immersion. For this reason, the copolymer generally should not be made via emulsion

polymerization, which typically requires a surfactant. Preferably, the vinyl acetate copolymer may be made by suspension, bulk, or solution

polymerization.

[0029] While not being bound by theory, it is believed that the vinyl acetate copolymer layer partially hydrolyzes in the presence of the strong aqueous alkaline environment of wet concrete. The acetate functional group is converted to an alcohol. The water soluble or swellable vinyl alcohol copolymer becomes intimately bonded with the concrete once the concrete has set. Since the vinyl acetate copolymer is not easily hydrolyzed at lower pH, e.g. pH 7, it cannot be washed off by rain. It is not slippery when wet. The vinyl acetate copolymer layer is also non-tacky and will not bond well to the carrier sheet 4, thus permitting easy unrolling of the membrane and eliminating the need for a release liner.

[0030] The protective coating layer may be formed from solid polymer (e.g., a polymer melt) or from a solvent based polymer solution.

[0031] The protective coating layer of the present invention also preferably includes a reflective pigment to improve degradation resistance for the protective layer as well as the adhesive layer. The reflective pigment may be selected from highly reflective inorganic pigments, which are preferred, to moderately reflective inorganic pigments, as well as mixtures of two or more of such pigments. Highly reflective inorganic pigments include T1O2, ZnO, and Sb203. Moderately reflective inorganic pigments include calcium carbonate, white Portland cement, silica, barites, clay, magnesium silicate and talc. The level of inorganic material, including reflective pigment, is 5% to 40%, preferably 10% to 25%, by weight of total solids in the protective coating layer. The aforementioned minimum level of reflective pigment is preferred to provide for UV protection for the adhesive layer. However, an excessive level of inorganic material (i.e., above the aforementioned maximum level) will cause the protective layer to be brittle and fracture.

[0032] The vinyl acetate copolymer may also be blended with a plasticizer to increase flexibility. Suitable plasticizers include, but are not limited to, phthalates (e.g., dimethyl-, diethyl-, dibutyl-, and butylbenzyl- phthalate), benzoates (e.g., diethylene glycol dibenzoate and dipropylene glycol

dibenzoate), phosphates (tributyl-, tricresyl-, triphenyl-, and tributoxyethyl- phosphate), and triacetine (glycerol triacetate). Generally, the plasticizer level may be any suitable amount sufficient to soften the vinyl acetate copolymer protective coating layer, with the maximum plasticizer level being no more than 30% by weight of the protective coating layer (i.e., the combination of plasticizer plus vinyl acetate copolymer).

[0033] The vinyl acetate copolymer layer may comprise other ingredients selected from a list including antioxidants, hindered amine light stabilizers (HALS), and UV absorbers. Preferred UV absorbers include benzotriazoles, triazines, and benzophenones. Hindered amine light stabilizers, UV absorbers, and/or reflective pigments are intended to provide degradation resistance to the vinyl acetate copolymer protective coating layer as well as degradation resistance for the pressure sensitive adhesive layer. The combined level of antioxidant, hindered amine light stabilizer and/or UV absorber is 1% to 15% by weight, based on organics (excluding pigments).

[0034] Although not required for good bonding to concrete, the protective coating layer preferably has a penetration less than or equal to 25 dmm (150 g. 5 sec, 70° F.), as measured according to ASTM D 5 (150g for 5 sec), for good trafficability. Adding plasticizer will increase penetration. Adding inorganic filler to the protective coating layer will decrease penetration. [0035] The thickness of the protective coating ranges from 25 μηι (1.0 mils) to 125 μηι (5 mils). A minimum of 1 mil is required to provide for adequate protection of the adhesive.

[0036] The protective coating layer 6 may optionally include a coating or dusting of finely divided, reflective, inorganic particulate material (not shown) on its outer exposed surface. The particulate inorganic material serves to protect the protective coating layer 6, and the underlying adhesive layer 4, from the elements prior to casting concrete against it. Preferably, it also improves the adhesion to post-cast concrete. The particulate inorganic material may include calcium carbonate, sand, silicate sand, white Portland cement, talc, titanium dioxide, clay, alumina trihydrate, hydrated or partially hydrated white ground cement, and mixtures of two or more of these materials. Preferably, the particulate inorganic material will have an average particle size in the range of about 0.1-1000 μηι, and more preferably in the range of about 0.2 to 100 μηι.

[0037] Although not required, the waterproofing membrane may include a removable release sheet (not shown) on the protective coating layer 6. The release sheet comprises a film or paper that is coated with a release agent, preferably a silicone. The film may comprise polyethylene, polypropylene, polyethylene terephthalate, or polyamide. A paper release sheet may also be coated with a polyolefin layer prior to being coated on the polyolefin face with a silicone release agent. The thickness of the release sheet is typically about 0.01- 0.13 mm (about 0.5-5 mils).

[0038] The waterproofing membrane may be manufactured in a continuous web coating operation with two coating stations. Pressure sensitive adhesive is applied at one coating station and the vinyl acetate copolymer layer is applied at the second coating station. The pressure sensitive adhesive may be coated onto the carrier sheet as a hot melt by a coating device such as a knife over roll coater, slot die coater, or roll coater. This two layer construction comprising a carrier sheet and the pressure sensitive adhesive may be cooled. Then the vinyl acetate copolymer layer may be coated (e.g., by hot melt or solvent coating) onto the exposed face of the pressure sensitive adhesive by a coating device such as a knife over roll coater, slot die coater, or roll coater. The vinyl acetate copolymer layer may be coated at the same width as the pressure sensitive adhesive or alternatively, it may be coated at a slightly narrower width than the pressure sensitive adhesive layer, leaving one edge of the pressure sensitive adhesive layer uncoated. This narrow uncoated area, referred to as selvedge, is operable to form an adhesive overlap between two adjoining sheets of membrane. The exposed pressure sensitive adhesive edge may be laminated to a silicone coated release strip that, when removed, will form an adhesive overlap between two adjoining sheets of membrane. In the final step the membrane is wound into a roll.

[0039] An alternative construction method involves a two-step process. The protective coating layer may be coated onto a release liner, dried and then wound into a jumbo roll. This roll is unwound and the pressure sensitive adhesive layer is coated onto the protective coating. The carrier sheet is laminated to the pressure sensitive adhesive and then the laminate is wound into a roll. As a further alternative construction method, the method described in WO 2010/048198, the disclosure of which is incorporated herein by reference, may be used.

[0040] The invention may be better understood by reference to the following examples.

EXAMPLE 1

[0041] A protective coating comprising a vinyl acetate copolymer is prepared as follows. A dispersion of 55% T1O2 in MEK (methyl ethyl ketone) is prepared with a pigment dispersant (1% on T1O2), Disperse-ayd® 15. The pigment grind is mixed in a 1 quart (0.95 1) can with a lab scale Cowels dissolver (5 cm or 2 in) at 2000 rpm for 15 min. A separate 40% solution of poly (vinyl acetate/vinyl laurate (20%)) (Vinnapas® B500/VL20) in MEK is prepared. The T1O2 dispersion is mixed with the copolymer solution, a hindered amine light stabilizer (Tinuvin® 770) and a UV absorber (Tinuvin® 328 or Tinuvin® 571 (used in laminate no. 3 only) for 5 min at 500 rpm. [0042] The protective coating formulation is shown in Table 1. The formulation comprising only solids is shown in Table 2.

Table 1 Coating formulation

dry film thickness (mils) 1.2

wet film thickness (mils) 3.0

volume % solids 39.0

weight % solids 43.2

weight % filler/pigment on solids 20.1

Pigment Volume Concentration % 6.5

40% Vinnapas B500/VL 20 in MEK % 82.8

55% T1O2 dispersion in

MEK/1% Disperse-ayd® 15 on solids % 15.8

HALS % 0.66

UV Absorber % 0.66

Table 2 Coating Formulation - Solids

Ingredient wt %

Poly (vinyl acetate/vinyl laurate (20%))

Vinnapas® B500/VL 20 76.83

Ti0₂ 19.91

Disperse-ayd® 15 0.20

Hindered amine light stabilizer (HALS) 1.53

UV Absorber 1.53

[0043] The solvent based coatings are cast with a draw down bar onto a silicone coated polyethylene terephthalate (PET) film (or release sheet). Coatings are dried at room temperature for 1 hr and then for 5 minutes at 93°C (200°F) in a forced hot air oven to ensure solvent removal. The dry film thickness is 30.5 μηι (1.2 mil).

[0044] Waterproofing membranes are prepared as follows. Two layer laminates comprising a 0.10 mm (4 mil) polyethylene carrier sheet and a bituminous pressure sensitive adhesive are prepared. The laminates comprise five different adhesive formulations (as shown in Table 3) comprising SBS radial block copolymer, SB block copolymer, AC 20 asphalt and aromatic oil. The protective coating face of the above- described PET release sheet is laminated to the face of the pressure sensitive adhesive layer of the above-described laminate to prepare a waterproofing membrane comprising carrier sheet, pressure sensitive adhesive layer, protective coating layer, and release sheet. The various membranes are illustrated in Table 3.

Table 3 - Membrane Formulations and Properties

Adhesive

Thickness Adhesive Co mponents BTC BTC

No. mm (mils) SBS % SB % Oil % Asphalt % Initial 7 M J

1 0.91 (36) 3 12 10 75 14.0 9.0

2 0.91 (36) 3 12 10 75 11.3 9.3

3 0.91 (36) 3 12 10 75 14.6 10.0

4 0.91 (36) 3 12 10 75 10.0 5.1

5 0.91 (36) 3 12 10 75 9.5

6 0.91 (36) 3 12 20 65 9.0

7 0.91 (36) 8 6 16 70 10.8 14.5

8 0.91 (36) 8 6 16 70 10.8

9 0.91 (36) 8 6 16 70 10.3

10 0.56 (22) 7 14 30 49 3.6

11 0.56 (22) 6 6 0 88 9.9 6.3

12 0.56 (22) 6 6 0 88 11.5

[0045] The above- described membranes are tested for initial bond to concrete (BTC) and bond to concrete (BTC) after 7 mjoules of accelerated UV exposure (EMMAQUA). In the latter case, the protective coating is exposed to 7 mj of UV exposure prior to casting concrete and then testing the bond to concrete. Concrete is cast against the protective coating face of a 2.54 cm (1 in) wide sample of each membrane and allowed to cure for seven days. Peel adhesion is measured with an Instron mechanical testing machine at an angle of 90° and a peel rate of 5.08 cm/min (2 in/min). The BTC results are shown in Table 3. All specimens exhibit good initial bond to concrete and good bond to concrete after UV exposure.

Claims

1. A waterproofing membrane in the form of a sheet-like laminate consisting essentially of a carrier sheet, a pressure sensitive adhesive layer on one surface of the carrier sheet, and a protective coating layer on a surface of the adhesive layer opposite that which abuts the carrier sheet, wherein the protective coating layer consists essentially of a vinyl acetate copolymer having a Tg of 10°C to 35°C.

2. The waterproofing membrane according to claim 1 wherein the vinyl acetate copolymer is a copolymer of vinyl acetate with a comonomer selected from the group consisting of a vinyl alkanoic acid ester, wherein the alkanoic acid moiety has from 8-18 carbon atoms, a C3 to C10 alpha olefin, and an acrylic ester of a lower alkanol.

3. The waterproofing membrane according to any preceding claim wherein the protective coating layer comprises a reflective pigment dispersed therewithin, wherein the amount of the reflective pigment comprises 5% to 40% by weight of total solids in the protective coating layer.

4. The waterproofing membrane according to any preceding claim wherein the protective coating layer comprises a reflective pigment dispersed therewithin, wherein the amount of the reflective pigment comprises 10% to 25% by weight of total solids in the protective coating layer.

5. The waterproofing membrane of claim 3 wherein the reflective pigment comprises a highly reflective pigment selected from the group consisting of Ti0₂, ZnO and Sb₂0₃.

6. The waterproofing membrane of claim 3 wherein the reflective pigment comprises a moderately reflective pigment selected from the group consisting of calcium carbonate, white Portland cement, silica, barites, clay, magnesium silicate and talc.

7. The waterproofing membrane according to any preceding claim wherein the vinyl acetate copolymer comprises a copolymer of vinyl acetate and vinyl alkanoic acid ester, wherein the alkanoic acid moiety has from 8-18 carbon atoms.

8. The waterproofing membrane according to any preceding claim wherein the vinyl acetate copolymer comprises a copolymer of vinyl acetate and vinyl laurate.

9. The waterproofing membrane according to any preceding claim wherein the vinyl acetate copolymer comprises a copolymer of vinyl acetate and vinyl laurate, wherein the vinyl acetate comprises about 80% of the copolymer by weight and the copolymer has a glass transition temperature (Tg) of about 21°C.

10. The waterproofing membrane according to any preceding claim wherein the protective coating layer has a thickness of about 25 μηι to about 125 μπι.

11. The waterproofing membrane according to any preceding claim wherein the vinyl acetate copolymer additionally comprises a plasticizer.

12. The waterproofing membrane according to any preceding claim wherein the vinyl acetate copolymer additionally comprises one or more members selected from the group consisting of antioxidants, hindered amine light stabilizers and UV absorbers.

13. The waterproofing membrane according to any preceding claim additionally including a coating or dusting of finely divided, reflective, inorganic particulate material on the exposed surface of the protective coating layer.

14. The waterproofing membrane according to any preceding claim wherein the carrier sheet comprises a film comprising polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-olefin copolymer, ethylene-vinyl acetate copolymer, polyvinyl acetate, polyethyl acrylate, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene terephthalate, polyvinyl chloride, polyamide and combinations thereof, or a woven or non- woven fabric comprising polyethylene, polypropylene, polyolefin, polyethylene terephthalate, glass, or polyamide.

15. The waterproofing membrane according to any preceding claim wherein the pressure sensitive adhesive layer comprises a rubber modified bitumen pressure sensitive adhesive.

16. The waterproofing membrane according to any preceding claim wherein the pressure sensitive adhesive layer comprises a synthetic pressure sensitive adhesive comprising a butyl rubber based adhesive, a

polyisobutylene based adhesive, a butyl based adhesive, an acrylic based adhesive, a vinyl ether based adhesive, a styrene-isoprene-styrene (SIS) based adhesive, a styrene-ethylene-butylene-styrene (SEBS) based adhesive, a styrene-butadiene-styrene (SBS) based adhesive, a styrene-butadiene rubber (SBR) based adhesive, or a combination of two or more of these materials.

17. The waterproofing membrane according to any preceding claim additionally comprising a removable release sheet on the protective coating layer.

18. A method of waterproofing a concrete structure comprising applying a waterproofing membrane in accordance with any preceding claim to a building substrate or concrete form with the protective coating layer of said membrane facing the area into which the concrete will be cast, and casting concrete such that it contacts the protective coating layer of the membrane.