Modified carboxylated polyolefins and their use as adhesion promoters for polyolefin surfaces

Abstract

The present invention provides solvent- and water-based primer compositions that include at least one carboxylated polyolefin that has been modified with one or more polyfunctional alcohols. The carboxylated polyolefins are obtained by the reaction of polyolefins with at least one of unsaturated carboxylic esters, unsaturated carboxylic acids, unsaturated carboxylic anhydrides, acrylic monomers, and mixtures thereof. The carboxylated polyolefins are then further modified by reaction with one or more polyfunctional alcohols. These polyfunctional alcohol-modified polyolefins may also contain pendant carboxyl groups, which have the propensity to form hydrophilic salts with amines or inorganic bases, thereby rendering the polyfunctional alcohol-modified polyolefins water-dispersible. These primer compositions are useful for significantly improving the adhesion of paints, adhesives, and inks to various plastic and metal substrates.

We claim: 
     
         1 . A water-based primer composition, comprising: the reaction product of an amine or inorganic base with the polyfunctional alcohol modified carboxylated polyolefin; water; and optionally, a surfactant;
 wherein said polyfunctional alcohol-modified carboxylated polyolefin comprises the reaction product of: at least one carboxylated polyolefin prepared from a polyolefin having a heat of fusion of 0 to 10 calories/gram; and at least one polyfunctional alcohol.   
     
     
         2 . The water-based primer composition of  claim 1 , wherein the carboxylated polyolefin is the reaction product of: at least one polyolefin polymer selected from the group consisting of: ethylene copolymers prepared from ethylene and alpha olefins having 3 to about 10 carbon atoms; polypropylene; propylene copolymers containing ethylene or alpha olefins having from 4 to about 10 carbon atoms; poly(1-butene); propylene terpolymers prepared from ethylene and/or alpha olefins having from 4 to about 10 carbon atoms; and 1-butene copolymers prepared from 1-butene and ethylene or alpha olefins having 3 to about 10 carbon atoms; and at least one monomer selected from the group consisting of an unsaturated carboxylic acid ester, an unsaturated carboxylic acid, an unsaturated carboxylic anhydride, a vinyl monomer, and an acrylic monomer. 
     
     
         3 . The water-based primer composition of  claim 2 , wherein the polyolefin polymer is an ethylene-propylene copolymer comprised of about 80 mole percent propylene and about 20 mole percent ethylene. 
     
     
         4 . The water-based primer composition of  claim 2 , wherein the at least one monomer includes at least one member selected from the group consisting of maleic anhydride, citraconic anhydride, itaconic anhydride, glutaconic anhydride, 2,3-dimethylmaleic anhydride, maleic acid, fumaric acid, citraconic acid, mesaconic acid, glutaconic acid, acrylic acid, methacrylic acid, crotonic acid, 2-pentenoic acid, 2-methyl-2-pentenoic acid, dimethyl maleate, diethyl maleate, di-n-propyl maleate, diisopropyl maleate, dimethyl fumarate, diethyl fumarate, di-n-propyl fumarate, diisopropyl fumarate, dimethyl itaconate, methyl acrylate, hydroxyethyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, methyl crotonate, ethyl crotonate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, and mixtures thereof. 
     
     
         5 . The water-based primer composition of  claim 1 , wherein the at least one polyfunctional alcohol includes at least one member selected from the group consisting of trimethylolethane, pentaerythritol, trimethylolpropane, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,2-propylene glycol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, diethylene glycol, triethylene glycol, polyethylene glycols, glycerol, polyester polyols, acrylic polyols, polyurethanepolyols, glucose, and sucrose. 
     
     
         6 . The water-based primer composition of  claim 1 , wherein the polyfunctional alcohol comprises one primary hydroxyl group and one secondary or tertiary hydroxyl group. 
     
     
         7 . The water-based primer composition of  claim 6 , wherein the polyfunctional alcohol is at least one member selected from the group consisting of 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and 1,2-propylene glycol. 
     
     
         8 . The water-based primer composition of  claim 7 , wherein the surfactant is present and is a nonionic surfactant. 
     
     
         9 . The water-based primer composition of  claim 8 , wherein the amine is an aliphatic amine. 
     
     
         10 . The water-based primer composition of  claim 8 , wherein the amine is at least one member selected from the group consisting of ammonia, ammonium hydroxide, trimethylamine, diethylamine, monoethanolamine, monoisopropanolamine, morpholine, ethanolamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, 2-amino-2-methyl-1-propanol, and N-methyldiethanolamine. 
     
     
         11 . An article of manufacture, comprising a plastic or metal substrate, a primer coating comprising the water-based primer composition of  claim 1 , and a topcoat. 
     
     
         12 . The article of  claim 11 , wherein the topcoat comprises at least one of melamine and urethane. 
     
     
         13 . The article of  claim 11 , wherein the article is comprised of at least one of metal and plastic. 
     
     
         14 . A coating composition, comprising:
 at least one coating resin;   a polyfunctional alcohol-modified carboxylated polyolefin; and,   optionally, one or more additives selected from the group consisting of a leveling agent, a rheology agent, a flow control agent; an associative thickener, a flatting agent, a pigment wetting and dispersing agent, a surfactant, an ultraviolet (UV) absorber, an ultraviolet (UV) light stabilizer, a tinting pigment, a defoaming agent, an antifoaming agent, an anti-settling agent, an anti-sag agent, a bodying agent, an anti-skinning agent, an anti-flooding agent, an anti-floating agent, a fungicide, a mildewcide, a corrosion inhibitor, a thickening agent, and a coalescing agent; wherein the polyfunctional alcohol-modified carboxylated polyolefin comprises the reaction product of: at least one carboxylated polyolefin prepared from a polyolefin having a heat of fusion of 0 to 10 calories/gram; and at least one polyfunctional alcohol.