Waterproofing membrane

1. A waterproofing membrane comprising the following laminated layers:

layer A comprising a carrier sheet;

layer B comprising a waterproofing adhesive;

layer C comprising a protective coating, wherein the protective coating is substantially free of surfactant and comprises an acrylic or methacrylic polymer or copolymer, an inorganic filler and a white pigment, the protective coating having a penetration ≦20 dmm and a reflectivity greater than or equal to 55% as measured by a reflectometer perpendicular to a surface illuminated at a 45° angle, and wherein the protective coating has a pigment volume concentration in terms of filler plus white pigment in the range of 30% to 80%; and

layer D comprising a releasable material, wherein the releasable material comprises amorphous nanoscale silica and a polymeric binder; and

wherein the laminated layers are arranged in the sequential order A-B-C-D.

2. The waterproofing membrane according to claim 1 wherein the nanoscale silica is present in an amount of 30% to 90% by volume of the silica plus polymeric binder.

3. The waterproofing membrane according to claim 1 wherein the nanoscale silica has a particle size of 0.1 nm to 150 nm.

4. The waterproofing membrane according to claim 1 wherein the polymeric binder in the releasable material comprises a water soluble polymer, an alkali soluble polymer, or a homopolymer or copolymer of polyvinyl acetate.

5. The waterproofing membrane according to claim 4 wherein the polymeric binder comprises a water soluble polymer selected from the group consisting of polyvinyl alcohol (PVOH), polyethylene oxide (PEO), water soluble cellulosic polymers including hydroxypropyl methyl cellulose and hydroxyethyl cellulose, hydrolyzed maleic anhydride polymers and copolymers, polyvinylpyrrolidone, sulfonated polystyrene, polysulfoethyl acrylate, poly(2-hydroxyethylacrylate), polyacrylamide, poly(acrylic acid) and alkali metal salts thereof, natural or synthetically modified polysaccharides, proteins, alginates, xanthan gums, and guar gums.

6. The waterproofing membrane according to claim 5 wherein the polymeric binder comprises polyvinyl alcohol.

7. The waterproofing membrane according to claim 4 wherein the polymeric binder comprises an alkali soluble polymer selected from the group consisting of copolymers of styrene and maleic anhydride, copolymers of styrene, maleic anhydride and half-ester of maleic anhydride, copolymers of acrylic acid and styrene and/or alpha-methyl styrene, hydroxypropyl methylcellulose acetate succinate, copolymers of methacrylic acid and methyl methacrylate, copolymers of methyl methacrylate, ethyl methacrylate and acrylic acid, copolymers of ethyl acrylate, methyl methacrylate, and acrylic acid, a rosin acid, a phenolic resin, and combinations of one or more of these.

8. The waterproofing membrane according to claim 4 wherein the polymeric binder comprises a homopolymer or copolymer of polyvinyl acetate.

9. The waterproofing membrane according to claim 1 wherein the carrier sheet has a thickness of about 0.05 to 2.0 mm; the waterproofing adhesive has a thickness of about 0.07 to2.0 mm; the protective coating has a thickness of about 0.008to 0.08mm; and the releasable material has a thickness of about 0.5 to15 μm.

10. The waterproofing membrane according to claim 1 wherein the protective coating) has a dry coating weight of about 20 g/m 2 to 90 g/m 2 on a dry solids basis; and wherein the releasable material has a dry coating weight of 1 g/m 2 to 15g/m 2 .

11. The waterproofing membrane according to claim 1 wherein the filler in the protective coating is selected from the group consisting of calcium carbonate, silica, diatomaceous earth, barytes, magnesium silicates, talc, clay, and alumina trihydrate, and mixtures of two or more of these materials.

12. The waterproofing membrane according to claim 1 wherein the white pigment in the protective coating comprises titanium dioxide, and wherein the volume percent of white pigment comprises 5% to 3% by volume of filler plus white pigment.

13. The waterproofing membrane according to claim 1 wherein the carrier sheet comprises polyethylene, polypropylene, ethylene-propylene copolymers, ethylene-olefin copolymers, ethylene-vinyl acetate copolymers, polyvinyl acetate, polyethyl acrylate, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene terephthalate, polyvinyl chloride or a combination of two or more of these materials.

14. The waterproofing membrane according to claim 1 wherein the waterproofing adhesive comprises a synthetic pressure sensitive adhesive or a rubber modified bitumen pressure sensitive adhesive.

15. The waterproofing membrane according to claim 14 wherein the waterproofing adhesive 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.

16. The waterproofing membrane according to claim 1 wherein the membrane does not include a removable release sheet.

17. The waterproofing membrane according to claim 1 wherein

the nanoscale silica is present in an amount of 60% to 90% by volume of the silica plus polymeric binder;

the nanoscale silica has a particle size of 1 nm to 50 nm; and

the protective coating has a reflectivity from 65% to 85% as measured by a reflectometer perpendicular to a surface illuminated at a 45° angle, and wherein the pigment volume concentration of the filler plus white pigment is 40% to 70% based on total solids in the protective coating.

18. A method of waterproofing a concrete structure comprising applying a waterproofing membrane according to claim 1 to a building substrate or concrete form with the releasable material of said membrane facing the area into which the concrete will be cast, and casting concrete such that the concrete contacts the releasable material of the membrane.

19. A method of making a waterproofing membrane according to claim 1 , comprising the following steps:

(S1) coating the releasable material layer onto the plastic film and drying;

(S2) coating the protective coating layer onto the releasable material layer, drying, and winding the releasable material layer, the plastic film, and the protective coating layer into a roll;

(S3) coating the waterproofing adhesive layer onto the carrier sheet;

(S4) unwinding the three layer roll comprising the protective coating layer, the releasable material layer, and the plastic film and laminating the protective coating layer to the waterproofing adhesive layer; and

(S5) removing the plastic film from the releasable material layer and winding the four layer construction comprising the releasable material layer, the protective coating layer, the waterproofing adhesive layer, and the carrier sheet into a roll, whereby the carrier sheet is located outwardly of the roll.