Epoxy modified acrylic latices and method of producing same

• US 4,028,294 A
• Filed: 11/10/1975
• Issued: 06/07/1977
• Est. Priority Date: 11/10/1975
• Status: Expired due to Term

• Current Assignee: Valspar Corporation (Sherwin-Williams Company)
• Original Assignee: Mobil Oil Corporation (Exxon Mobil Corporation)
• Inventors: Brown, George L., Tobias, Michael A.
• Primary Examiner(s): Welsh, M. J.
• Application Number:
  US05/630,610
• Time in Patent Office: 575 Days
• Field of Search: 260/29.6 NR, 260/837 R
• US Class Current: 523/423
• CPC Class Codes: C08F 283/10 on to polymers containing more than one epoxy radical per molecule C08F283/004 takes precedence

Abstract

Acrylic latices containing epoxy resins are prepared by emulsion polymerization in which an epoxy resin (polyepoxide) is incorporated into at least one of the monoethylenic monomers, including an epoxy-reactive monomer, and the monomers including the epoxy resin are emulsified into water containing surfactant to provide the oil phase of an oil-in-water emulsion. The monomers are then polymerized in the aqueous emulsion using a free radical polymerization catalyst and a reaction temperature which does not cause premature reaction between the epoxy groups and the reactive monomer. This provides thermosetting latex particles of fine particle size in the presence of less emulsifying agent than is normally needed.

Claims

1. A method of producing a thermosetting aqueous latex comprising dissolving a polyepoxide which is a diglycidyl ether of a bisphenol having a molecular weight in the range of 350-4000 into at least one of the monoethylenically unsaturated monomers to be polymerized, said monomers including from 2 to 30% of monoethylenic carboxylic acid, and the balance of said monomers consisting essentially of nonreactive monoethylenic monomers, emulsifying said monomers and polyepoxide in water with the aid of from 0.25-3 parts of surfactant per 100 parts of said monomers, polymerizing said monomers in said aqueous emulsion with the aid of a free radical polymerization catalyst and at a temperature below which said carboxylic acid will react with the epoxy groups of said polyepoxide, the relative proportion of said polyepoxide and said carboxylic acid monomer varying from about a stoichiometrically equivalent amount up to a 50% equivalent excess of said carboxylic acid monomer, and adding ammonia to said latex to provide a pH of 7.0-9.0 to stabilize the latex and catalyze the cure thereof.

2. A method as recited in claim 1 in which the epoxy reactive monomer comprises acrylic acid or methacrylic acid.

3. A method as recited in claim 1 in which at least 45% of said monomers are nonreactive monoethylenic monomers which produce hard homopolymers.

4. A method as recited in claim 3 in which said monomers producing hard homopolymers are selected from methyl methacrylate, styrene, vinyl toluene, acrylonitrile and vinyl acetate.

5. A method as recited in claim 1 in which said polyepoxide is dissolved in said monomers to provide a liquid mixture, said liquid mixture being added incrementally to the water containing said surfactant and said free radical polymerization catalyst, and heated to polymerization temperature.

6. A method as recited in claim 1 in which said monoethylenic carboxylic acid is present in an amount of from 3 to 15% of the total monomers.

7. A thermosetting aqueous latex coating composition produced as defined in claim 1.