Graft polymer compositions of terminated epoxy resin, processes for making and using same, and substrates coated therewith

A process for preparing an ionizable resinous reaction product that is dispersible in an aqueous ionizing medium which comprises:

• reacting a modified resin, formed by reacting an aromatic 1,2-epoxy diepoxide resin that has aliphatic backbone carbons and a molecular weight of at least 1,000 with a chemical terminating agent for the diepoxide, that reacts with the epoxy groups of the diepoxide resin, substantially to eliminate the epoxide groups of the resin and form the modified resin, with at least one monoethylenically unsaturated addition polymerizable monomer, in the presence of benzoyl peroxide in an amount of at least 3% by weight based on the weight of the monomer, at a temperature in the range from about 110.degree. C. to 130.degree. C. or under equivalent free radical initiating conditions for the reaction including the use of a peroxide initiator, simultaneously to effect polymerization of the monomer through its ethylenic unsaturation and to form graft polymer by a free radical reaction by replacement of hydrogen with addition polymer component grafted to at least some of said backbone carbons, at least some of said monomer units in said addition polymer component comprising ionizable carboxyl groups, the modified resin contributing at least 30% by weight to the resinous reaction product,
• the resinous reaction product obtained containing a sufficient number of ionizable carboxyl groups for establishing the reaction product as a dispersion in an aqueous ionizing medium.

A process for reacting a modified aromatic 1,2-epoxy diepoxide resin that has aliphatic backbone carbons and a molecular weight prior to modification of at least 4,000, and that has been reacted with a chemical terminating agent that reacts with the epoxy groups substantially to eliminate the epoxy groups of the resin and form the modified resin, with at least one monoethylenically unsaturated addition polymerizable monomer comprising an acrylic acid, to render the reaction product dispersible in an aqueous ionizing medium, comprising:

• reacting said modified resin with monoethylenically unsaturated addition polymerizable monomer, containing from 10% to 80% by weight thereof of an acrylic acid that would be reactive with the epoxide groups of unmodified epoxy resin, in the presence of an amount of at least 4% of benzoyl peroxide by weight of the monomer of about 110.degree. C. to 130.degree. C., or under equivalent free radical initiating conditions for the reaction including the use of peroxide initiator, simultaneously to effect polymerization of the monomer through its ethylenic unsaturation and to form graft polymer with addition polymer grafted to the modified resin by a carbon-to-carbon bond in place of a hydrogen atom that is bonded thereto in the ungrafted state, the unmodified epoxy contributing at least 50% by weight of the solids of the reaction product;
• the reaction product being acid functional, and the Acid Number being sufficiently high for establishing the reaction product as a dispersion in an aqueous medium in which the product is ionized.

A process for forming a resinous reaction mixture that is dispersible in an aqueous ionizing medium comprising:

• (a) reacting an aromatic 1,2-epoxy diepoxide resin that has aliphatic backbone carbons and a molecular weight of at least 1,000 with a chemical terminating agent for the resin, that reacts with the epoxy groups of the diepoxide resin, substantially to eliminate the epoxy groups of the resin and to form modified resin;
• then
• (b) reacting with said modified resin a mixture of monoethylenically unsaturated monomers including an acrylic acid, in the presence of about 6.8% by weight of the monomer mixture of benzoyl peroxide at about 110.degree. C. to 130.degree. C., and to effect the simultaneous addition polymerization of the monomers through their ethylenic unsaturation and to form graft polymer with an addition copolymer component grafted to the modified epoxy resin by a carbon-to-carbon bond at a said aliphatic backbone carbon thereof, and then
• (c) recovering the reaction mixture, the acid functionality of the reaction mixture being sufficiently high to effect dispersion of the reaction mixture in a basic aqueous medium, the amount of said epoxy resin employed in step (a) being sufficient to contribute at least 30% by weight of said reaction mixture.

A resinous reaction product that is dispersible in an aqueous ionizing medium comprising ionizable graft polymer substantially free from terminal epoxy groups, said graft polymer having an epoxy resin component that in its ungrafted state consisted of a modified epoxy resin formed by reacting an aromatic 1,2-epoxy diepoxide resin having aliphatic backbone carbons and a molecular weight of at least 350 with a chemical terminating agent for the resin, that reacts with the epoxy groups of the resin, substantially to eliminate the epoxy groups of the resin, and said graft polymer having addition polymer side chain component bonded to at least some of said aliphatic backbone carbons by carbon-to-carbon bonds each of which bonds replaces a hydrogen atom that is bonded to an aliphatic backbone carbon in the ungrafted state, each said side chain comprising polymerized units of monoethylenically unsaturated monomer, the ionizable sites being located in the side chain component, the ionizability being sufficient for establishment of the product as a dispersion in an aqueous medium containing an ionizing agent, said graft polymer being formed by the reaction of said modified epoxy resin and said monoethylenically unsaturated monomer in the presence of at least 3% by benzoyl peroxide by weight based on monomer, or under equivalent free radical initiating conditions for the reaction including the use of a peroxide initiator, at a temperature in the range from about 80.degree. C. to 200.degree. C., and said epoxy resin, as unmodified, contributing at least 10% by weight to said resinous reaction product.

A blend of polymeric ingredients that is dispersible in a basic aqueous ionizing medium, said blend being the reaction product of:

• (a) from about 30 to 90 parts by weight of a modified aromatic 1,2-epoxy diepoxide resin that has an average unmodified molecular weight of at least about 1,000, and aliphatic backbone carbons that have one or two carbons bonded thereto, and that is modified by being chemically terminated through reaction with a phenol or a carboxylic acid substantially to eliminate its epoxy groups, and
• (b) from about 10 to about 70 parts by weight of at least one addition polymerizable monoethylenically unsaturated monomer comprising an acrylic acid;
• (c) in the presence of at least 3% of benzoyl peroxide by weight of said monomer and at a temperature in the range from about 110.degree. C. to about 130.degree. C., or under equivalent free radical initiating conditions for the reaction using a peroxide initiator, at about 30.degree. C. to about 200.degree. C., the amount of initiator being sufficient simultaneously to effect addition polymerization of the monomer through its ethylenic unsaturation and to form graft polymer with addition polymer grated to the modified epoxy resin by carbon-to-carbon bonding, each of which bonds replaces a hydrogen atom that is bonded to a said aliphatic backbone carbon in the ungrafted state;
• said reaction product including graft polymer in which the modified epoxy resin has addition polymer grafted thereto, ungrafted associatively-formed addition polymer polymerized through its ethylenic unsaturation, and ungrafted epoxy resin, said reaction product having an Acid Number in the range from 45 to 150, and said graft polymer and associatively-formed addition polymer being acid-functional,
• the Acid Number being sufficiently high for establishing said reaction product as a dispersion in a basic aqueous medium in which said reaction product is ionized.

An associatively-formed resinous blend that is dispersible in an aqueous ionizing medium comprising:

• (a) ionizable graft polymer;
• (b) ionizable, ungrafted addition polymer;
• and
• (c) ungrafted modified epoxy resin;
• said modified epoxy resin being the reaction product of an initial aromatic 1,2-epoxy diepoxide resin having a molecular weight above 1,000 and a chemical terminating agent that is a phenol or a carboxylic acid and that reacts with the epoxy groups of the resin, to eliminate them;
• said modified epoxy resin having aliphatic backbone carbons including some carbon atoms that have one or two hydrogens bonded thereto;
• said graft polymer having a backbone component of said modified epoxy resin and, grafted thereto, addition polymer side chain component, said grafting being to at least some of said aliphatic carbons by carbon-to-carbon bonds each of which replaces a hydrogen atom that is bonded to an aliphatic backbone carbon in the ungrafted state;
• said graft polymer being formed by the reaction of said modified epoxy resin and at least one monoethylenically unsaturated monomer in the presence of at least 3% of benzoyl peroxide by weight based on monomer at a temperature in the range from 110.degree. C. to 130.degree. C., or under equivalent free radical initiating conditions for the reaction including the use of a peroxide initiator, at a temperature in the range from about 30.degree. C. to about 200.degree. C., the modified epoxy resin component of said graft polymer and the ungrafted modified epoxy resin together constituting from 30% to 90% of said blend by weight;
• the ungrafted addition polymer and grafted addition polymer component being formed by polymerization through monoethylenic unsaturation of monomer comprising an acrylic acid,
• both said addition polymer and said addition polymer component being acid functional,
• the Acid Number of the blend being sufficiently high for establishing the reaction product mixture as a dispersion in a basic aqueous medium.