GB1240289A - Improvements in or relating to abrasive webs - Google Patents

Abstract

1,240,289. Resin compositions; polymer compositions; starch compositions. REICHHOLDALBERT CHEMIE A.G. 24 Oct., 1968 [25 Oct., 1967 (2); 31 May, 1968], No. 50547/68. Headings C3B, C3P and C3U. [Also in Division C4] A resin composition for application as an intermediate elastic sealing layer in a coated abrasive web comprises a cured reaction product of an epoxide resin based on bisphenol A, an epoxide resin based on bisphenol A and internally plasticized with castor oil and a carbamic acid alkyl ester. The proportions of the ingredients may be in the ratio 10 : 90 : 0.5 to 90 : 10 : 80. Liquid resins can be used solventfree. In Example 1, 170 parts of an epoxide resin based on bisphenol A (medium viscosity, epoxide equivalent 185-195, chlorine content 0À3% and viscosity 10,000-15,000 cP at 25‹ C.), 30 parts of a bisphenol A epoxide resin internally plasticized by reaction with castor oil (epoxide equivalent 450-550, chlorine content 0.2% and viscosity 40,000-50,000 cP at 25‹ C.), three parts of carbamic acid ethyl ester and 37.5 parts of metaphenylene diamine were mixed before application to a support. Core sizes for application to the webs may consist of 30-90 parts by weight of corn starch, rice starch or potato starch which has been digested by acid degradation, 3-20 parts by weight of a fatty alcohol polyglycol ether, 10 50 parts of an aqueous acrylate copolymer dispersion, the copolymer being derived from 35% ethylacrylate, 10% methacrylic acid, 15% acrylamide and 40% methylmethacrylate and 957-840 parts of water. Another preferred core size consists of 1-25 parts by weight of water-soluble copolymer of 30% acrylic acid and 70% butyl acrylate, 315 parts of a coconut fatty alcohol polyglycol ether having 5-12 ethylene oxide molecules per fatty acid alcohol molecule, 10-80 parts of an aqueous acrylate copolymer dispersion, the copolymer being derived from 45% ethylacrylate, 35% butylacrylate, 10% vinylacetate and 10% of N-methanol acrylamide and 986-870 parts of water. Finishing agents for the coated abrasive products may comprise 10-100 parts of animal hide glue, 80-30 parts of an aqueous acrylate copolymer dispersion, the copolymer containing 45-20% of ethylacrylate, 5-20% methacrylic acid, 0-10% of methylmethacrylate, 5-25% acrylonitrile, 0-45% butyl acrylate and 5- 15% N-methylolacrylamide, 5-10 parts of a coconut fatty alcohol polyglycol ether, 1-35 parts of chlorinated hydrocarbons, such as methylene chloride, and 78-864 parts of water. Reference has been directed by the Comptroller to Specification 1,122,211.