Europäisches Patentamt *EP000986593B1* (19) European Patent Office Office européen des brevets (11) EP 0 986 593 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.7: C08G 18/10, C08G 18/66, of the grant of the patent: C08G 18/50, C09D 175/02, 02.01.2002 Bulletin 2002/01 B05D 7/00 (21) Application number: 98918777.8 (86) International application number: PCT/US98/08443 (22) Date of filing: 27.04.1998 (87) International publication number: WO 98/55525 (10.12.1998 Gazette 1998/49) (54) POLYUREA ELASTOMER SYSTEMS WITH IMPROVED ADHESION TO SUBSTRATES POLYHARNSTOFF-ELASTOMERSYSTEME MIT VERBESSERTER HAFTUNG AUF SUBSTRATEN SYSTEMES ELASTOMERES DE POLYUREE A ADHERENCE AMELIOREE SUR DES SUBSTRATS (84) Designated Contracting States: (72) Inventor: PRIMEAUX, Dudley, Joseph, II BE CH DE ES FR GB LI NL SE Elgin, TX 78621 (US) (30) Priority: 05.06.1997 US 869385 (74) Representative: Winkler, Andreas, Dr. 03.04.1998 US 54979 FORRESTER & BOEHMERT Pettenkoferstrasse 20-22 (43) Date of publication of application: 80336 München (DE) 22.03.2000 Bulletin 2000/12 (56) References cited: (73) Proprietor: HUNTSMAN PETROCHEMICAL EP-A- 0 344 512 US-A- 5 415 499 CORPORATION US-A- 5 442 034 US-A- 5 626 917 Austin, Texas 78752 (US) US-A- 5 631 341 Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 0 986 593 B1 Printed by Jouve, 75001 PARIS (FR) EP 0 986 593 B1 Description Field of the Invention 5 [0001] The invention relates to aliphatic and aromatic polyurea elastomers and processes for making the same, and, in one aspect, more particularly relates to methods and compositions for making aliphatic and aromatic polyurea elas- tomers having improved adhesion to wet substrates via use of a special polyurethane primer which can penetrate the substrate. The polyurea systems may be applied via spray, 2-part caulk, pour, brush-on or other method, 10 Background of the Invention [0002] Spray elastomer systems are commonly recognized as coating materials, with aliphatic and aromatic isocy- anate spray polyurea elastomer systems being particularly useful when employed in this capacity. This two-component technology is based on an isocyanate quasi-prepolymer and an amine coreactant, often an amine resin blend. 15 [0003] It is further known to use spray polyurea elastomer coatings as liners on the inside of rail cars, and on surfaces such concrete, wood, etc. Such coatings should be highly conformal to the surface sprayed and should have excellent adhesion to the surface for the lifetime of the coating. Increasingly strict environmental regulations continue to reduce the volatile organic compound (VOC) emissions permitted during the application of such coatings. These requirements have forced the coatings to have higher solids and lower solvent contents and/or be entirely water-based systems. 20 [0004] The following excerpt from G. H. Brevoort, "Current Trends and Issues in Railcar Painting and Lining," Journal of Protective Coatings and Linings, December, 1991, is instructive. [0005] "Without a doubt, the driving force in the past decade to develop high solids, improved protective coatings and linings with reduced VOCs has come from The Clean Air Act and its amendments. [0006] "Some residual benefits accrue from the use of high solids, VOC-conformant coatings and linings. For exam- 25 ple, the number of gallons required is fewer, which results in fewer containers to ship, handle, open, apply and dispose of. While the price per gallon is higher, the contents per container are greater and go further so that fewer gallons are required. Much less solvent is being packaged, shipped and emitted. Often, the actual material cost for a job is reduced with more concentrated, high-solids products. Most important, many in the industry, including individual users, are being environmentally responsible. 30 [0007] "It is not easy to formulate high solids, VOC-conformant coatings and linings. Solvents are not just removed and replaced with more solids. Among the problems encountered are maintaining suspension of the mixed products (non-settling), maintaining their application and handling characteristics, producing coatings with the ability to build adequate drying and recoating times for practical use. Leveling of the applied coating film to create a smooth appear- ance has been particularly difficult to achieve." 35 [0008] One advantage of spray polyurea technology is that no foaming is noted even if the elastomer system is applied to a wet substrate. However, in some cases the moisture acts as a barrier to mechanical/chemical adhesion. There are commercially available water emulsifiable isocyanates used as substrate primers for spray elastomer sys- tems. For wet substrates, these primers have poor penetration properties, giving poor elastomer coating system ad- hesion and possible foaming. 40 [0009] There is thus a continuing need to develop new systems to address the varied requirements of spray polyurea coatings. Various known polyurea systems have been employed which address some of these parameters. [0010] For example, U.S. Pat. No. 5,266,671 to Dudley J. Primeaux, II of Huntsman Petrochemical Corporation describes a spray polyurea elastomer which exhibits improved resistance to abrasion. The elastomer includes an isocyanate, an amine terminated polyoxyalkylene polyol, a chain extender and a chemically sized filler material. The 45 isocyanate is preferably a quasi-prepolymer of an isocyanate and a material selected from at least one polyol, a high molecular weight polyoxyalkyleneamine or a combination thereof. A method for making a spray polyurea elastomer which is substantially resistant to abrasion is also disclosed. [0011] Spray polyurea elastomers made from an (A) component and a (B) component, where the (A) component has a quasi-prepolymer made from an isocyanate and an active hydrogen-containing material, such as a polyoxy- 50 alkylenepolyamine, is described in U.S. Pat. No. 5,442,034 to Dudley J. Primeaux, II of Huntsman Petrochemical Corporation. The (B) component includes an amine resin, such as an amine-terminated polyoxyalkylene polyol which may be the same or different from the polyoxyalkylene polyamine of the quasi-prepolymer. The viscosity of the (A) component is reduced by the inclusion of an organic, alkylene carbonate, such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate and the like. The alkylene carbonate also serves as a compatibilizer 55 between the two components, thus giving an improved mix of the system. [0012] U.S. Patent 5,415,499 discloses a method of repairing manholes by spraying polyurea on the surface. An aqueous silane solution is used as a primer. [0013] EP 0 344 512-A2 discloses polyurethane formulations where castor oil is employed as an ingredient. 2 EP 0 986 593 B1 Summary of the Invention [0014] Accordingly, it is an object of the present invention to provide a polyurea elastomer system, which can be applied via spraying or otherwise, which can be directly applied to a wet substrate with little or no foaming. 5 [0015] It is another object of the present invention to provide a polyurea elastomer system which has excellent ad- hesion to a substrate over which it is applied, even if the substrate is wet. [0016] Another object of the invention is to provide a polyurea elastomer system where the polyurea elastomer may be applied over a primer even when the primer is not completely cured. [0017] In carrying out these and other objects of the invention, there is provided, in one form, a polyurea elastomer 10 system having a primer, where the primer contains a water emulsifiable isocyanate, and a hydrophobic, primary hy- droxyl-containing compound. The system also employs a polyurea elastomer which contains a quasi-prepolymer of an isocyanate, and an active hydrogen-containing material; at least one amine resin; and at least one amine-terminated chain extender. 15 Detailed Description of the Invention [0018] It has been discovered that by utilizing a water emulsifiable isocyanate, and by using castor oil instead of water, a primer system with good penetration to the wet substrate can be realized. Even prior to cure of the primer, a fast cure spray polyurea elastomer system can be applied, thus giving a complete elastomer system with excellent 20 adhesion to wet substrates. Indeed, the primer may be immediately coated with the spray polyurea elastomer. Any residual moisture would not cause any foaming problems with the spray polyurea elastomer. [0019] In one embodiment, the primer is prepared such that an excess of isocyanate groups would be present. This would permit an actual chemical bond between the primer and the spray polyurea elastomer. Without being bound by any particular theory, the castor oil appears to allow the isocyanate to penetrate through the moisture into the substrate 25 before curing. [0020] The polyurea spray elastomer part of the system, in one embodiment of the invention, may be prepared by mixing an isocyanate component with a resin blend component, a blend of polyoxyalkylene diamines and/or triamines and amine-terminated chain extenders, in high pressure impingement mix spray equipment and can be directly applied to a primed substrate. The inventive polyurea elastomer system is expected to have excellent flexibility and elongation. 30 Superior abrasion and impact resistance are also anticipated advantages of the system. [0021] The polyurea spray elastomer systems of this invention contain no solvents and thus have little or no VOCs. They are thus considered 100% solids systems to comply with VOC requirements. [0022] Polyurea spray systems cure rapidly even under low ambient temperature conditions.