Patent GB-907296-A (GB)
Title: Method of providing polyester resins with protective surface layers
IPC: B32B27/00
Filed: 1959-11-11
Abstract: A synthetic resin article, with a weather-resistant, adherent, transparent surface, chemically bonded to the body of the article, ia made by: (I) mixing together a composition comprising (A) a major proportion of an unsaturated liquid polyester resin and a "vinylidene" co-monomer, and (B) a minor proportion of an ultraviolet light stabilizer and a polymerization initiator; (II) spreading this composition upon a film, e.g. of regenerated cellulose, to a thickness of from 0,1 to 25 thou. and allowing it to gel; (III) contacting the exposed side of the surface composition with a copolymerizable composition comrising (A) an unsaturated polyester resin and (B) a "vinylidene" co-monomer (very widely defined); and (IV) heating the product to cure it and chemically bond the surface composition to the copolymerizable composition.  The Specification includes lists of acids and glycols from which the polyester may be prepared, of vinylidene and other olefinically unsaturated co-monomers, ultraviolet light stabilizers, and polymerization initiators and accelerators.  The polyesters of both layers may contain combined halogen, e.g. by using acids or glycols which are Diels-Alder adducts formed from hexahalocyclopentadienes.  The regenerated cellulose film may be stripped from the finished product. The surfacing composition may also contain a hydrocarbon wax.  The body of the article may be reinforced, e.g. with glass fibre mat, and may have layers of ultraviolet light stabilizer-containing composition on both sides.  In the examples, polyseter compositions containing ultraviolet light stabilizers are spread on regenerated cellulose films, allowed to gel and then applied to one or both sides of glass fibre mats coated with polyester resin and catalyst, and heated to cure.ALSO:A synthetic resin article, with a weather-resistant, adherent, transparent surface, chemically bonded to the body of the article, is made by: (I) mixing together a composition comprising (A) a major proportion of an unsaturated liquid polyester resin and a comonomer, and (B) a minor proportion of an ultra-violet light stabilizer and a polymerization initiator; (II) spreading this composition upon a film, e.g. of regenerated cellulose, to a thickness of from 0,1 to 25 thou. and allowing it to gel; (III) contacting the exposed side of the surface composition with a copolymerizable composition comprising (A) an unsaturated polyester resin and (B) a comonomer containing a <FORM:0907296/IV(a)/1> group; and (IV) heating the product to cure it and chemically bond the surface composition to the copolymerizable composition.  The Specification includes lists of acids and glycols from which the polyester may be prepared, of comonomers, ultra-violet light stabilizers, and polymerization inhibitors, initiators and accelerators.  The principal types included are:-acids-maleic, fumaric, aconitic, itaconic, chorolmaleic, Diels-Alder adducts containing Cl, Br and F atoms, phthalic, chlorophthalic and oxalic and its homologues; glycols-alkanediols and triols, trimethylol alkanes, pentaerythritol and dipentaerythritol; comonomers-styrene, vinyl toluene, divinyl-benzene, diallyl phthalate, maleate and 1,4,5,6,7,7-hexachlorobicyclo-(2,2,1)-5-heptene-2,3-dicarboxylate, triallyl phosphate and esters of acrylic, methacrylic, maleic and itaconic acids; inhibitors-hydroquinone, chloranil and nitric acid; initiators-t-butyl-, MEK- and benzoyl peroxides and cumene hydroperoxide; accelerators-Pb, Co, Mn, Va and Fe octoates, naphthenates, gallates and tallates, N,N-dimethyl aniline and dodecyl mercaptan; U-V stabilizers-numerous 2-hydroxybenzophenones, salicylates, substituted benzotriazoles and dibenzoyl resorcinol. The polyesters of both layers may contain combined halogen, e.g. by using acids or glycols which are Diels-Alder adducts formed from hexahalocyclopentadienes.  The regenerated cellulose film may be stripped from the finished product.  The surfacing composition may also contain a hydrocarbon wax.  The body of the article may be reinforced, e.g. with glass fibre mat, and may have layers of ultra-violet light stabilizer-containing composition on both sides. In the examples, polyester compositions containing ultra-violet light stabilizers are spread on regenerated cellulose film, allowed to gel and then applied to one or both sides of glass fibre mats coated with polyester resin and catalyst, and heated to cure.  The examples also describe by way of comparison articles produced by impregnating glass fibre mats with the polyester resin compositions containing also ultra-violet light stabilizers, but without any surface layer of different composition.