Patent GB-805527-A (GB)
Title: Improvements in or relating to coating compositions
IPC: C09D109/00
Filed: 1957-02-26
Abstract: A composition comprising an oily liquid polymer of butadiene-1,3 and an orthotitanate ester or an orthozirconate ester is used for coating the interior of metal containers, e.g. of tin-plated steel, sheet steel, terne-plate and aluminium-clad steel, for food packaging.  The coating may be applied by roller-coating, spraying, dipping and flow-coating.  The polymer may be a homo-polymer of butadiene or a copolymer of butadiene and styrene in which the butadiene is in preponderance; it is preferably an oily liquid having a molecular weight of 700-20,000.  It may also be modified by a minor proportion, e.g. up to 2 per cent by weight of maleic anhydride or citraconic anhydride.  The ester used may be (1) an orthotitanate or orthozirconate ester of an aliphatic monohydric alcohol preferably of 6 to 20 carbon atoms such as 2-ethyl-hexyl alcohol; (2) an orthotitanate or orthozirconate ester of a 2,3-diorgano-substituted 1,3-diol such as 2-ethylhexane diol-1,3; these chelated derivatives are described in U.S.A. Specification 2,643,262 and may be formed in situ in the composition by introducing the titanium or zirconium derivative as the tetrabutyl ester and adding the diol; (3) an orthotitanate or orthozirconate ester of an enolixable beta-ketoacid ester, such as the C1-C6 alkyl and cyclohexyl alcohol esters of acetoacetic, beta-oxo-valeric, beta-oxo-caproic, beta-oxo-caprylic, or beta-oxo-cyclo-hexanepropionic acid; these chelates may also be similarly formed in situ; (4) an orthotitanate or orthozirconate partial ester of an aliphatic monohydric alcohol and partial acylate of a fatty oil acid, such as polymeric isopropoxytitanium oleate. These partial anhydrides-partial esters are described in U.S.A. Specifications 2,621,193, 2,621,195 and 2,666,772.  The coating composition is dissolved in a volatile inert organic mutual solvent for the polymer and ester.  Hydrocarbons or hydrocarbon mixtures boiling within the range of 80-220 DEG  C. are preferred, such as mineral spirits.  "Varnish Makers' and Painters'" naphtha and petroleum naphthas.  Other conventional solvents can also be added. The solvent or diluent should be free of water.  An aliphatic monohydric alcohol may also be added to provide the liquid product with viscosity stability and resistance to gelation.  The alcohol may be added in an amount of 30-400 per cent by weight based on the orthotitanate or orthozirconate ester; it may be unsaturated and contain up to 20 carbon atoms, a large number being specified. There may also be added metal driers such as iron, cobalt or manganese salts of 2-ethylhexoic acid, liquid siloxane polymers to alter the surface characteristics of the coating, 1-5 per cent by weight based on the polymer of a flexibilizer such as tri-2-ethylhexyl phosphate, compatible resins and plasticizers and conventional pigments, extenders, fillers, lakes and dyes.  The liquid coating composition may contain 10-70 per cent by weight of non-volatile matter and is applied to give a coating of 2-10 mg. per square inch for use as an interior coating of containers for the packaging of wetpack food products.  After the solvent has evaporated the coating is cured by baking at 200-420 DEG  F. for 60-5 minutes.ALSO:A composition comprising an oily liquid polymer of butadiene-1,3 and an orthotitanate ester or an orthozirconate ester is used for coating the interior of metal containers for food packaging.  The polymer may be a homopolymer of butadiene or a copolymer of butadiene and styrene in which the butadiene is in preponderance, it is preferably an oily liquid having a molecular weight of 700-20,000.  It may also be modified by a minor proportion, e.g. up to 2 per cent by weight of maleic anhydride or citraconic anhydride.  The ester used may be (1) an orthotitanate or orthozirconate ester of an aliphatic monohydric alcohol, preferably of 6 to 20 carbon atoms such as 2-ethylhexyl alcohol; (2) an orthotitanate or orthozirconate ester of a 2,3-diorgano-substituted 1,3-diol such as 2-ethylhexane diol-1,3. These chelated derivatives are described in U.S.A.  Specification 2,643,262 and may be formed in situ in the composition by introducing the titanium or zirconium derivative as the tetrabutyl ester and adding the diol; (3) an orthotitanate or orthozirconate ester of an enolizable beta-ketoacid ester, such as the C1-C6 alkyl and cyclohexyl alcohol esters of acetoacetic, beta-oxo - valeric, beta - oxo - caproic, beta - oxo-caprylic, or beta - oxo - cyclo - hexanepropionic acid. These chelates may also be similarly formed in situ.  (4) an orthotitanate or orthozirconate partial ester of an aliphatic monohydric alcohol and partial acylate of a fatty oil acid, such as polymeric isopropoxytitanium oleate.  These partial anhydrides-partial esters are described in U.S.A. Specifications 2,621,193, 2,621,195 and 2,666,772.  The coating composition is dissolved in a volatile inert organic mutual solvent for the polymer and ester.  Hydrocarbons or hydrocarbon mixtures boiling within the range of 80-220 DEG  C. are preferred, such as mineral spirits. "Varnish Makers' and Painters'" naphtha and petroleum naphthas. Other conventional solvents can also be added.  The solvent or diluent should be free of water.  An aliphatic monohydric alcohol may also be added to provide the liquid product with viscosity stability and resistance to gelation.  The alcohol may be added in an amount of 30-400 per cent by weight based on the orthotitanate or orthozirconate ester; it may be unsaturated and contain up to 20 carbon atoms, a large number being specified. There may also be added metal driers such as iron, cobalt or manganese, salts of 2-ethylhexoic acid, liquid siloxane polymers to alter the surface characteristics of the coating, 1-5 per cent by weight based on the polymer of a flexibilizer such as tri-2-ethylhexyl phosphate, compatible resins and plasticizers and conventional pigments, extenders, fillers, lakes and dyes.  The liquid coating composition may contain 10-70 per cent by weight of non-volatile matter and is applied to give a coating of 2-10 mg. per square inch for use as an interior coating of containers for the packaging of wet-pack food products.  After the solvent has evaporated the coating is cured by baking at 200-420 DEG  F. for 60-5 minutes.