Waterproofing laminate with integral release coating

Abstract: The present waterproofing laminates comprise a flexible sheet-like polymeric support having a first major side thereof coated with a release coating which is substantially non-adherent to bituminous compositions and having a second major side thereof coated with a flexible membrane layer of an adhesive bituminous composition, wherein said release coating can be removed with wet abrasion. These laminates can be formed into rolls for shipment without the need for a large release paper layer over the bituminous adhesive layer. The present invention also relates to a novel method of forming tight overlap seams between the adjacent layers of the present laminates. The method involves washing the first applied layer with a wet abrasion before applying an upper overlapping laminate.

Description: FIELD OF THE INVENTION The present invention is directed to a novel waterproofing laminate which does not require the need for a separate, disposable, release sheet. Particularly, the present invention relates to improved bituminous waterproofing laminates. The present invention is also directed to novel methods of making and using the abovementioned waterproofing laminates. BACKGROUND OF THE INVENTION It is known that concrete surfaces and the like can be sealed in a waterproof manner by forming or applying thereon a membrane of a bituminous composition, such as asphalt, tar or pitch, which is substantially impermeable to moisture and water vapor. Preformed sheet-like materials useful for this purpose are well known. Examples of these materials are disclosed in U.S. Patent Nos. 3,741,856, 3,853,682 and 3,900,102. These waterproofing materials have a laminate structure of a support sheet adjacent to a membrane of bituminous composition which has adhesive properties which renders it adherent to the support material and to the substructure, such as a concrete slab, to which it is applied. Laminate structures presently commercially available are supplied in the form of rolls which further comprise a flexible release sheet adjacent to the exposed surface of the bituminous membrane. This release sheet is a required component in the present mode of manufacture and serves, in the end product, to prevent the adhesive membrane from adhering to the sheet immediately adjacent thereto when in roll form. The release sheet does not form a part of the finally applied sheet-like structure which renders a substructure waterproof and, therefore, creates problems of removal and disposal at the job site. Preformed flexible, sheet-like waterproofing material requires the utilization of a release sheet, such as in the form of a siliconized paper, as an integral component in the presently known methods of formation. A release sheet capable of withstanding high temperatures is used as a forming surface upon which a hot semi-fluid bituminous composition, generally having a temperature of about 121°C (250°F), or greater, is applied. The composition must be cooled prior to superimposing a polymeric support on its free surface in order to minimize deterioration of the support. The resultant laminate structure, including the release sheet, is then formed into rolls for shipment. Alternatively, when support sheets having a non-adherent free surface are used, the formed support/membrane laminate is formed into rolls for storage and shipment by removing the laminate from the release sheet at the end of the manufacturing process. Recently, waterproofing laminates have been developed which eliminate the need for a separate release sheet. US-A-4,215,160 to Rosenberg and Gaidis describes a waterproofing laminate comprising a bituminous asphalt layer and a carrier sheet which eliminates the need for a release sheet by applying a release agent, specifically a poly(dimethylsiloxane) based release coating, to the backside of the carrier sheet prior to producing the product roll of laminate. Thus, a release agent-carrier-bituminous asphalt "jelly roll" is formed. When laminates are applied to a concrete surface, adjacent layers are typically overlapped. Unfortunately, when the laminate of US-A-4,215,160 is utilized the uppermost laminate's bituminous adhesive layer must be laid down over the release agent-coated carrier layer of the already adhered sheet, onto which it cannot stick. Thus, the release agent at the overlapping seam must be scrubbed off with a suitable organic solvent. This practice is undesirable from health, safety and environmental viewpoints. As a result, this type of "paperless" waterproofing laminate has not met with success in the marketplace. US-A-4,172,830 discloses a waterproofing laminate having a major support sheet over the central region of the bituminous composition, and along at least one edge of the bituminous composition a strip of minor support sheet which is releasable therefrom by virtue of a weak adhesion thereto. SUMMARY OF THE INVENTION The present invention provides a novel preformed sheet-like waterproofing laminate structure of a flexible sheet-like membrane and an adhesive bituminous composition which does not require a separate disposable release sheet and, furthermore, incorporates a release agent which is applied as a water-based emulsion and is readily removed by wet abrasion; thus, eliminating the shortcomings of prior laminates. The present waterproofing laminates comprise a flexible sheet-like polymeric support having a first major side thereof coated with a release coating which is substantially non-adherent to bituminous compositions and having a second major side thereof coated with a flexible membrane layer of an adhesive bituminous composition, wherein said release coating is applied as a water-based emulsion and can be removed with wet abrasion. The present invention also relates to a novel method of manufacturing the abovementioned waterproofing laminates. The method comprises applying a flexible polymeric support, one major side of which is coated with a release coating which is non-adherent with respect to bituminous compositions, which is applied as a water-based emulsion and which can be removed by wet abrasion. The polymeric support is applied with its non-adherent major side in a face-to-face relationship with the forming surface. A hot bituminous composition having a temperature above the melting point of the polymeric support member is applied to the other major side of the polymeric support while simultaneously cooling for a time sufficient to cause the bituminous composition to become handleable. The present method does not require the utilization of a heat resistant release sheet during the formation or packaging of the laminate structure. The present invention also relates to a novel method of forming tight overlap seams between the adjacent layers of the present laminates. The method involves removing the first applied layer with a wet abrasion, drying the surface and then applying an upper overlapping laminate. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows, in cross section, three sheets (1, 2 and 3) of the present laminate installed in overlapping fashion over a concrete surface 4 . The first sheet 1 is applied, the release coating over the overlap region 5 is wiped clean by wet abrasion and the next sheet 2 is applied. These steps are repeated for subsequent sheets. Fig. 2 shows a roll of the present laminate being applied. The product laminate 5 being applied, is similar to the product of figure 4 below. 14 ' is a thin strip of double-sided release paper along the overlap region 5 . This long-edge mounted release strip is removed from the first applied laminate 2 before the next applied laminate 3 is positioned. Thus, only the end laps need to be water washed before overlap. Fig. 3 is a diagram of the preferred mixing scheme for preparing the present release coating, where 6 is the silicone emulsion tank or container, 7 is the aqueous thickener solution tank or container, 8 is the water inlet line, 9 is the silicone catalyst emulsion tank or container, 10 is the mixing tank (preferably of minimum size) and 11 is the coating pan of minimized size and with no recycle, unless air knife coating equipment is used wherein a blow-off return line 16 is required. Fig. 4 is a cross-sectional representation of the preferred waterproofing laminate product, where 12 is a rubberized asphalt layer 914 mm (36 inch) wide, 13 is PET carrier film 902 mm (35½ inch) wide, 14 ' and 14 '' are 15.24 cm (6 inch) double-sided release strips along the edge and 15 is the wet abrasion removable silicone release coating. (NOTE: The edge mounted release strips are utilized because it is believed that it will be easier for the applicator to only have to wash the "end" laps. Furthermore, a single release strip product, as in Fig.2 above, is most preferred.) DETAILED DESCRIPTION OF THE INVENTION The waterproofing laminate of the present invention comprises a support sheet having superimposed on one major surface thereof a membrane of an adhesive bituminous composition. The opposite major surface of the support sheet is treated to be non-adherent to the bituminous membrane. The treatment must also be removable by wet abrasion. The present method permits the utilization of a wide variety of sheet-like polymeric supports to form waterproofing laminate structures. Generally the support should be substantially impermeable to water and, based on the laminate structure's end use, capable of stretching with movement of the concrete or other material of the substrate to which it is ultimately applied. The polymeric supports can be formed of natural rubber or of a synthetic organic polymer such as polyethylene, polypropylene or other polyolefin, a polyamide, a polyester, e.g., polyethylene terephthalate, a polyurethane, a polyvinyl halide, such as a polyvinyl chloride and copolymers thereof, such as a polyvinyl chloride and vinylidene chloride, a synthetic rubber, such as polychloroprene or butyl rubber, regenerated cellulose, cellulose, cellulose ethers or cellulose esters. The supports can be films in the form of solid sheets, cellular films or woven and non-woven fabrics which are sufficiently non-porous to restrict the flow of the hot bituminous composition therethrough when applied. Preferred support sheets are of poly(ethylene terephthalate) (PET) sheets, e.g. MYLAR and MELINEX brand sheets manufactured by E.I. Dupont deNemours, Wilmington, DE, and ICI, London, England, respectively, and REVVAL brand MR-32058 sheet, manufactured by E.I. DuPont de Nemours Co., Wilmington, DE. The preferred support typically are from about 12.7 µm to about 254 µm (about 0.5 to about 10 mils) in thickness. Valeron® brand oriented cross-laminated polyolefin film may also be used, however, due to its wettability, this film will require a wash coat as described below: The support sheet may be treated with a wash coat to improve the wettability of the release coating. The wash should be applied to the outward face and may be applied to both faces of the support sheet. Suitable wash coats have the following desirable characteristics: good adhesion to polyethylene film; and, low surfactant content. A preferred wash coat is DARAN 820 polyvinylidene chloride emulsion manufactured by W.R. Grace & Co.-Conn., Lexington, MA. Support sheets which are pre-coated with a wash coat may also be used, e.g. , Revval P86, manufactured by E.I. DuPont de Nemours, which has an acrylic wash coat on both sides. The outside, i.e. non-bituminous, face of the support must be treated with a release coating. The release coating should be capable of making the surface substantially non-adherent to the bituminous material being used. The coating can be formed in any known manner at any time prior to application of the support to a forming surface as described hereinbelow. For example, the release coating can be formed on one of the major surfaces of the support by the deposition of an emulsion silicon composition which is cured by the aid of a catalyst and/or heat. The support can then be formed into rolls for storage and delivery to the site of formation of the waterproofing laminate structure. The support sheet can have any additional conventional features incorporated into its structure. The release coating of the present invention must be non-adherent with respect to the bituminous compositions and must be readily removed by wet abrasion. As used herein the term "non-adherent" means that it prevents adhesion between two surfaces. Samples are deemed to be non-adherent if they yield a Keil release of less than 39.4g/cm (100gm/in) as determined by the method outlined herein below: Keil Release Test for Rubberized Asphalt Laminate Purpose: This test procedure shall be the standard method for determining the release characteristic of rubberized asphalt laminate. It is an indication of the amount of force necessary to pull the silicone release paper from the mastic in the composite rubberized asphalt laminate. Standard Test Method: A. Equipment 1. Keil tester, with 0-500 gram scale, by Dow Corning (Model No. 2), or OHaus Model 8012. 2. Sample of rubberized asphalt laminate 7.62 cm by 15.24 cm (3" by 6") which has been conditioned for approximately 30 minutes in the lab. Procedures: 1. Take a 7.62 cm by 15.24 cm (3" by 6") sample of rubberized asphalt laminate to be tested and draw a line down the sample 2.54 cm (one inch) from the center of the 7.62 cm (3") side, on each side of the center (i.e., the lines should be 12.7 mm (0.5 inch) from the sides of the sample), or use a 5.08 cm (2") wide templet. 2. Run a razor along each line or edge of the templet so that the silicone release paper is cut through to the mastic. 3. Using scotch tape, tape the sides of the rubberized asphalt laminate sample so that none of the mastic is visible (this is to prevent the mastic from adhering to the Keil Tester). 4. Peel back about 2.54 cm (1 inch) of the 5.08 cm (2 inch) wide portion of the release paper and fold the paper over on itself. Tape the exposed rubberized asphalt laminate with scotch tape. 5. Place the rubberized asphalt laminate sample in the Keil Tester, making sure that the 7.62 cm (3") side containing the folded release paper and taped-over rubberized asphalt laminate is at the bottom. 6. Fasten the silicone coated paper to the scale. Fasten the taped-over rubberized asphalt laminate to the fixed clamp at the base of the Keil Tester. 7. Start the Keil tester and record the reading on the scale at one inch intervals as the paper releases from the mastic. Record only the force at 5.08, 7.62, 10.16 and 12.6 cm (2, 3, 4 and 5 inches). According to the present invention, the release coating must be a coating which is removable by wet abrasion. As used herein the term "wet abrasion" means that the release coating can be rubbed off by hand with a water wet/damp cloth, rag, plastic pot scrubber, brush or towel. Preferably this type of release coating is a water-based silicone emulsion, most preferably these emulsions are fast curing. Silicone emulsions suitable for use in the present invention are described in U.S. Patent No. 4,190,688 to Traver et al. incorporated herein by reference. Suitable commercially available emulsion coatings include the SYL-OFF® System IV family of reactive silicone emulsions, the SYL-OFF® System VII family of emulsions containing reactive organofunctional silicone (both manufactured by Dow Corning Corp, Midland, MI) and water dilutable emulsions of reactive silicone polymers like SM 2145/SM 2146c Silicone Paper Release (manufactured by General Electric company, Waterford, NY). A preferred embodiment of the present invention has the following formula: Deionized water: 54.84% (wt.) 1.5% Sodium Alginate Solution: (Kelgin-MV --medium high viscosity, mfg. by Kelco Algin, Chicago, IL) 28.92% Polyalkylene oxide modified dimethyl polysiloxane surfactant: (Silwet L-7607, mfg. by Union Carbide Corp., Danbury, CT) 0.12% Silicone catalyst emulsion X-27741: (Mfg. by Dow Corning, Midland, MI) 8.05% Silicone polymer emulsion X-27740: (Mfg. by Dow Corning, Midland, MI) 8.05% Antifoam Emulsion (Dow Corning 1430 Antifoam) (Mfg. by Dow Corning, Midland, MI) 0.02% Σ 100.00% The above formula, at from 1% to 10% solids, is applied by either a rod coater or an air knife coater. An air knife coater is used to apply anywhere from 1.4 to 60 grams per square meter (wet) or 0.1 gm per square meter to 4 grams per square meter after drying. (Preferably 0.4 grams per square meter to 1.6 grams per square meter after drying). Dry coating weight can be measured by X-Ray fluorescence or other suitable methods. Other coating methods can be used. When using Meyer rods, suitable coatings can be achieved from a 3-7% silicone solids bath containing 1-2% carboxy methyl cellulose or 0.25-.5% sodium alginate. A #16 or #18 Meyer rod is typically used. When using the Direct Gravure method, suitable coatings can be achieved from a 7-15% silicone solids bath with and without thickener or extender depending on the base sheet. Good results can be obtained using 31.5 to 59 lines/cm (80-150 line/inch) gravure cylinder. When using the Offset Gravure methods, suitable coatings can be achieved from a 20-40% silicone solids bath without thickener. When using a size press, suitable coatings can be achieved from a 10-20% silicone solids bath without thickener or extender. Horizontal and inclined configurations are suitable, but vertical application is not recommended. Reverse roll coating method can also be used. The bituminous compositions of the present invention can be any tar, asphalt, pitch or the like which is adhesive to and will render waterproof the contemplated substructure on which the final laminate product is to be used, without the aid of heat or additional bonding agents at the site of application. Thus, for application to surfaces of concrete, which are comparatively rough and dusty, the layer of adhesive composition must be at least about 0.063 to 0.5 cm (0.010 to 0.2 inch), the thicker the layer of adhesive composition the better the waterproofing effect, but in general, a layer of about 0.08 to 0.25 cm (0.03 to 0.10 inch) which is suitable. Bituminous adhesive compositions are generally formed of natural or synthetic rubber, virgin or reclaimed, blended into bitumen to provide a smooth mix. The ratio by weight of bitumen to rubber is usually greater than about 75:25 with ratios of from about 80:20 to 95:5 being preferred. The compositions should be a non-solvent type which, preferably, is semi-fluid at temperatures of from about 125° C, and capable of application onto the support sheet as a coating. The resultant product is a flexible, pressure-sensitive membrane having cold flow properties. The resulting waterproofing laminate is preferably manufacture according to the method described in US-A-4,992,334; US-A-5,028,487 and US-A-4,442,148, all incorporated herein by reference; however, a support sheet with a pre-applied release coat is utilized and release paper is eliminated. The formed sheet-like waterproofing laminate structure is taken up as a roll with the non-adherent side of the support film in facing relationship with the free surface of the bituminous composition. Rolls of desired lengths of material are cut away from the remainder of the laminate structure to yield a free surface of the continuous belt, ready for additional formation of laminate structure. For vertical applications, the product can be rolled with the adhesive face on the inside. For horizontal applications, the product can be rolled with the adhesive face on the outside; thus, a small sheet of release paper is wrapped around the exposed adhesive to facilitate handling. As noted above, the novel waterproofing laminates provide a waterproof barrier over a surface, particularly a concrete surface, by unrolling a desired length of material, applying the exposed bituminous layer to said surface, removing the silicone coating over edges to be overlapped and forming overlap seals as needed in order to form a continuous membrane over the whole surface. The following example is given for illustrative purposes only and is not meant to limit the invention except as set forth by the claims hereinbelow. All parts and percentages are by weight except where otherwise indicated. EXAMPLE 1 Method of Preparing Release Coating A) A sodium alginate solution is prepared by adding 714.9 kg (1576 pounds) of deionized water to a large Cowles mixer. The Cowles mixer is then turned on to the slowest speed setting. 10.9 kg (24 pounds) of sodium alginate (Kelgin MV) is slowly sifted into the vortex of the water. The Cowles blade speed is increased as thickening occurs to keep the liquid surface moving rapidly. The solution is mixed 45 minutes or longer until the solution is smooth and free from lumps. The solution is transferred to clean drums for storage. The solution is allowed to stand overnight before using. The Brookfield viscosity should be 400 to 1500 centipoise using a #3 spindle at 60 RPM at 22.2°C to 24.4°C (72°F to 76°F). The sample must be at least 12 hours old before testing the viscosity. B) The coating is prepared in mixing equipment similar to the diagram in Figure 3. To the mix tank, 113.4 kg (250 pounds) of deionized water is added. 49.9 kg (110 pounds) of sodium alginate solution prepared according to step (A) above is then added. The mixture is mixed together without generating foam. 269 grams of silwet L-7607 wetting agent is added to a 22.75 l (5 gallon) plastic pail containing 4.54 kg (10 pounds) deionized water. The mixture is thoroughly mixed together with a small hand held mixer then this mixture is added to the large mixing tank containing the previously added ingredients. 18.55 kg (40.9 pounds) of Dow Corning X-27741 emulsion is added to the large mix tank. Mixing is continued without generating foam. 18.55 kg (40.9 pounds) Dow Corning X-27740 emulsion is added to the large mix tank. The solution is mixed without generating foam. 58 grams of Dow Corning DC-31 antifoam emulsion is added to the plastic pail containing 4.54 kg (10 pounds) deionized water. They are thoroughly mixed together with a small hand held mixer then this mixture is added to the large mixing tank containing the previously added ingredients. The final addition to the large mix tank is 17.33 kg (38.2 pounds) deionized water to bring the total tank contents to 226.8 kg (500 pounds) net weight. The final coating formula is 7.0% solids and has a Brookfield viscosity of 30 to 150 centipoise. C) The above coating is gravity fed to the coating equipment coating pan as required to keep the coating pan full. D) The coating is applied to the support film using an air knife coater as shown in Figure 3. The amount of wet coating applied to the support film is such that the final dry release coating weight is 0.1 grams per square meter to 4 grams per square meter and preferably 0.4 grams per square meter to 1.6 grams per square meter. The amount of wet coating applied to the support film is controlled by 1) the viscosity of the coating solution, 2) the speed and direction of the applicator roll, 3) the speed of the web through the coating equipment, 4) the air knife air pressure, 5) the angle of the air knife air jet to the support film, 6) the width of the air knife slot, and 7) the distance the air knife is from the support film. E) After the support film is coated the web passes through a hot air oven to dry the coating and to cure the silicone release coating without causing the support film to distort from reaching too high a temperature. For this process, the oven had five separate heating zones. The first to zones were set at 149°C (300°F) and the last three zones were set at 162.8°C (325°F). The total time in the oven is 20 seconds.

Claims: A waterproofing laminate (13,15) comprising a flexible sheet-like polymeric support (13) having a first major side thereof coated with a release coating (15) which is substantially non-adherent to bituminous compositions and having a second major side thereof coated with a flexible membrane layer (12) of an adhesive bituminous composition, characterised in that said release coating (15) is applied as a water-based emulsion whereby said release coating, when dried, is removable from said first major side of said support layer (13) by wet abrasion. A waterproofing laminate according to claim 1, wherein the release coating (15) is applied as a water-based silicone emulsion or a fast curing silicone emulsion. A waterproofing laminate according to claim 2, wherein the water-based silicone emulsion contains reactive organofunctional siloxane polymers. A waterproofing laminate according to any one of claims 1 to 3, wherein the release coating (15) is applied at a coating weight of from about 0.1 grams to about 4.0 grams per square meter after drying. A waterproofing laminate according to any one of claims 1 to 4, wherein the polymeric support (13) is in the form of solid sheets, cellular films or woven and non-woven fabrics which are sufficiently non-porous to restrict the flow of a hot bituminous composition when applied thereon. A waterproofing laminate according to claim 5, wherein the polymeric support (13) is poly(ethylene terephthalate), and optionally the bituminous composition is in the form of a membrane comprising tar, asphalt, pitch or the like, and rubber. A waterproofing laminate according to claim 5, wherein the polymeric support (13) is Valeron and further comprises a wash coating, preferably a polyvinylidene chloride emulsion, to improve wettability of the release coating. A waterproofing laminate according to any one of claims 2 to 7, wherein the water-based silicone emulsion contains water, a sodium alginate solution, polyalkylene oxide modified dimethyl polysiloxane surfactant, silicone catalyst emulsion, silicone polymer emulsion and antifoam emulsion. A method of forming a sheet-like, laminate, waterproofing structure of a flexible sheet-like polymeric member (13) having a first major side thereof substantially non-adherent to bituminous compositions and having a second major side thereof coated with a flexible membrane layer (12) of an adhesive bituminous composition comprising supplying a forming member having a forming and a non-forming surface; placing a flexible sheet-like polymeric member (13) on the forming surface of the forming member with its first major side facing the forming surface, said first major side being substantially non-adherent to the bituminous composition; applying said semi-fluid adhesive bituminous composition (12) to a second major side of the polymeric member in an amount sufficient to form about 0.003 to 0.5 cm (0.010 to 0.2 inch) thick; and continuously cooling the forming surface at least until the bituminous composition of said structure is handleable, characterised in that said polymeric member (13) has said first major side rendered non-adherent to the bituminous composition by being coated with a release coating (15) which is applied as a water-based emulsion whereby said release coating, when dried, can be removed by wet abrasion. A method according to claim 9, and including the step of cooling the forming surface of said forming member and the flexible sheet-like polymeric member (13) placed thereon before applying the semi-fluid adhesive bituminous composition (12) to the second major side of the polymeric member. A method of forming a sheet-like, laminate, waterproofing structure of a flexible sheet-like polymeric member (13) having a first major side thereof substantially non-adherent to bituminous compositions and having a second major side thereof coated with a flexible membrane layer (12) of adhesive bituminous compositions comprising supplying a forming member having a forming and a non-forming surface; placing a flexible sheet-like polymeric member (13) on the forming surface of the forming member with its first major side facing the forming surface; applying a semi-fluid adhesive butiminous composition (12) to the first major side, said first major side being substantially non-adhesive to the bituminous composition; and continuously cooling the forming surface at least until the bituminous composition of said structure is handleable; characterised by rolling the resulting laminate into a jelly roll-like structure, whereupon the exposed bituminous composition surface adheres to the polymeric member's second major side and by the fact that the first major side of the polymeric member is made non-adherent to the bituminous composition by coating with a release coating (15) which is applied as a water-based emulsion whereby said release coating, when dried, is removable from said first major side of said support layer by wet abrasion. A method of forming tight overlap seams between adjacent layers (1,2,3) of waterproofing laminates comprising a flexible sheet-like polymeric support (13) having a first major side thereof coated with a release coating (15) which is substantially non-adherent to bituminous compositions and having a second major side thereof coated with a flexible membrane layer (12) of an adhesive bituminous composition, wherein said release coating can be removed with wet abrasion and characterised in that the release coating (15) has been applied as a water-based emulsion which, when dried, can be removed from the first major side of the support layer (13) by wet abrasion; and in that the release coating (15) of the first applied laminate layer (1) on the portion of the laminate which is to be overlapped is removed by wet abrasion before the second applied, overlapping, laminate layer (2) is applied. A waterproofed structure comprising a structure having at least two adjacent waterproofing laminates (1,2,3) thereupon and having an overlap seam between adjacent said waterproofing laminates, wherein the waterproofing laminates (1,2,3) comprise a flexible sheet-like polymeric support (13) having (a) a first major side thereof coated with a release coating (15) which is removed from an edge of a first applied laminate before a subsequently applied laminate is overlapped with the first along that edge, and (b) a second major side thereof coated with a flexible membrane layer (12) of an adhesive bituminous composition; characterised in that the release coating (15) is applied as a water-based emulsion whereby said release coating, when dried, is substantially non-adherent to bituminous compositions and can be removed with wet abrasion and wherein the step of removing the release coating (15) of the first applied laminate layer (1) on the portion of the laminate which is to be overlapped is effected by wet abrasion before the second applied, overlapping, laminate layer (2) is applied.

Inventors: BENTZ DALE P, ROSENBERG ARNOLD M, WILSON JOHN E, BENTZ, DALE P., ROSENBERG, ARNOLD M., WILSON, JOHN E.
Applicants: GRACE W R & CO, W.R. GRACE & CO.-CONN.
Application year: 1992
Main classification: E04D5
IPC codes: B32B7, E04D5, E04B1, B32B11