Aqueous microgel from carboxyl latex polymer, acrylic-epoxy and diepoxide
AssigneeThe Glidden Company
InventorsGary P. Craun, Beth A. Smith, Neal S. Williams
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Abstract
An aqueous protective coating composition particularly useful for can coatings based on a polymeric binder comprises diepoxide crosslinked microgel particles. The microgel polymer is produced by dispersing into water a carboxyl functional acrylic-epoxy copolymer and combined with a carboxyl functional latex polymer along with a low molecular weight diepoxide, followed by coreaction and crosslinking between the carboxyl polymers and the diepoxide to form stable aqueous dispersed microgel particles. In a preferred aspect of the invention, the carboxyl latex polymer is a swollen latex polymer.
Claims16
An aqueous dispersed coating composition containing an aqueous dispersed polymeric binder, the polymeric binder comprising:
- an aqueous dispersed microgel containing a carboxyl functional latex polymer of emulsion polymerized ethylenic monomers including carboxyl functional monomers to provide an acid no. of above 15, a carboxyl functional acrylic-epoxy copolymer having an acid no. of above 30, the latex polymer and the acrylic-epoxy copolymer crosslinked with a low molecular weight diepoxide resin having an epoxide equivalent weight between 100 and 5000, where the microgel contains by weight of between 1% and 95% of latex polymer, between 1% and 95% of said acrylic-epoxy copolymer, with the balance being the crosslinking diepoxide resin;
- the acrylic-epoxy copolymer produced by the non-aqueous copolymerization of ethylenically unsaturated onomers in the presence of an epoxy resin at temperatures between about 80.degree. C. and 180.degree. C. in the presence of at least 1% or a peroxide initiator based on the weight of the monomers, the ethylenic monomers having by weight at least 5% of a carboxyl monomer, to produce the carboxyl functional acrylic-epoxy copolymer having an acid no. of above about 30, wherein said copolymer is dispersed in water by neutralizing at least part of the carboxyl functionality on said acrylic-epoxy copolymer to form a water dispersed acrylic-epoxy copolymer, wherein the water dispersed acrylic-epoxy copolymer is mixed with the latex polymer and the diepoxide, wherein the diepoxide is reacted with the carboxyl acrylic-epoxy coploymer and the carboxyl functional latex polymer to form aqueous dispersed crosslinked microgel particles having a particle side of below 5 microns.
An aqueous dispersed coating composition containing an aqueous dispersed polymeric binder, the polymeric binder comprising:
- an aqueous dispersed microgel of a carboxyl functional acrylic-epoxy graft copolymer having an acid no. of above about 30 dispersed into water with a carboxyl functional latex polymer having an acid no. above 15, wherein the carboxyl functional acrylic-epoxy graft copolymer and polymers latex are crosslinked with a low molecular weight diepoxide resin having an epoxide equivalent weight of between about 100 and 5000 to form the aqueous dispersed microgel, wherein the microgel contains at least 1% of the carboxyl functional acrylic-epoxy graft copolymer.
In a process for producing an aqueous dispersed coating composition containing an aqueous dispersed polymeric binder, the process steps comprising:
- copolymerizing by in-situ, non-aqueous polymerization of ethylenically unsaturated monomers, including a carboxyl functional monomer, in the presence of an epoxy resin and at least 1% of a peroxide initiator based on the weight of the monomers copolymerized, at temperatures of between about 80.degree. C. and 180.degree. C. to produce a carboxyl functional acrylic epoxy copolymer having an acid no. of above 30;
- combining the acrylic-epoxy copolymer with a carboxyl functional latex having an acid no. of above about 15 to provide an aqueous dispersion of carboxyl functional polymers;
- adding a low molecular weight diepoxide having an epoxide equivalent weight of between 100 and 5000 to the acrylic-epoxy copolymer or to the aqueous dispersion of carboxyl polymers;
- and
- crosslinking the carboxyl functional acrylic-epoxy copolymer and the carboxyl functional latex polymer with the diepoxide to produce stabilized, aqueous dispersed, microgel polymer particles having a particle size of less than 5 microns.
Dependencies are inferred from the claim text.