# US 10,119,018 B2 · Polyvinyl acetate latex

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- Number: US 10,119,018 B2
- Document ID: US10119018B2
- Status: Granted
- Kind: B2
- Application number: 15/338,530
- Filed: 2016-10-31
- Published: 2017-05-04
- Granted: 2018-11-06
- Earliest claimed: 2015-11-02
- Assignees: Rohm and Haas Company
- Applicants: Rohm and Haas Company
- Inventors: Kebede Beshah; James C. Bohling; Pu Luo
- Web page: https://patentgrep.com/patent/US10119018B2

## CPC

- C08L 31/04: Homopolymers or copolymers of vinyl acetate
- C08F 218/08: Vinyl acetate
- C09D 131/04: Homopolymers or copolymers of vinyl acetate
- C08F 230/02: containing phosphorus
- C08L 2201/52: Aqueous emulsion or latex, e.g. containing polymers of a glass transition temperature (Tg) below 20°C
- C08L 2205/025: containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)

## Abstract

The present invention relates to a process for preparing an aqueous dispersion of a vinyl acetate polymer comprising the step of polymerizing vinyl acetate under emulsion polymerization conditions in the presence of a chain transfer agent which is a hypophosphite salt or X—R1—SH, where R1 is a C1-C4 alkyl group and X is sulfonate, hydroxyl, sulfate, phosphate, phosphonate, carboxylic acid or a salt thereof, or C1-C3-alkyl carboxylate. The process provides a way of lowering the viscosity of the vinyl acetate polymer at a given solids content.

## Claims

### Claim 1

A composition comprising vinyl acetate polymer particles dispersed in an aqueous phase, wherein the aqueous phase comprises, based on the weight of the aqueous phase 1) 0.01 to 1 weight percent of a chain transfer agent; and 2) 0.05 to 2.5 weight percent of a vinyl acetate oligomer comprising:
a) from 40 to 90 weight percent structural units of vinyl acetate,
b) from 5 to 40 weight percent structural units of butyl acrylate,
c) from 0.2 to 3 weight percent structural units of phosphoethyl methacrylate, and
d) from 0.1 to 3 weight percent, based on the weight of the aqueous phase, structural units of a sulfur acid monomer selected from the group consisting of 2-acrylamido-2-methylpropane sulfonic acid, a salt of 2-acrylamido-2-methylpropane sulfonic acid, and sodium vinyl sulfonate;
wherein the chain transfer agent is selected from the group consisting of sodium hypophosphite, potassium hypophosphite, mercaptoethanesulfonate, mercaptopropionic acid, a salt of mercaptopropionic acid, mercaptoethanol, and methyl mercaptoproprionate; and wherein the vinyl acetate oligomer has a weight average molecular weight (Mw) in the range of from 1000 to 7000 Daltons.

### Claim 2 (depends on 1)

The composition of claim 1, wherein the chain transfer agent is sodium hypophosphite or potassium hypophosphite, wherein the weight average molecular weight of the oligomer is from 2000 to 5500 Daltons.

### Claim 3 (depends on 1)

The composition of claim 1 wherein the chain transfer agent is sodium hypophosphite at a concentration of from 0.02 to 0.5 weight percent, and the sulfur acid monomer is 2-acrylamido-2-methylpropane sulfonic acid or a salt of 2-acrylamido-2-methylpropane sulfonic acid.

### Claim 4 (depends on 1)

The composition of claim 1 wherein the chain transfer agent is selected from the group consisting of mercaptoethanesulfonate, mercaptopropionic acid, a salt of mercaptopropionic acid, mercaptoethanol, and methyl mercaptoproprionate at a concentration of from 0.02 to 0.5 weight percent, and the sulfur acid monomer is 2-acrylamido-2-methylpropane sulfonic acid or a salt of 2-acrylamido-2-methylpropane sulfonic acid.

### Claim 5 (depends on 4)

The composition of claim 4, wherein the chain transfer agent is mercaptopropionic acid or a salt thereof, wherein the weight average molecular weight of the oligomer is from 2000 to 4000 Daltons.

### Claim 6 (depends on 4)

The composition of claim 4, wherein the chain transfer agent is mercaptoethane sulfonate, wherein the weight average molecular weight of the oligomer is from 2000 to 5500 Daltons.

### Claim 7 (depends on 4)

The composition of claim 4, wherein the chain transfer agent is mercaptoethanol, wherein the weight average molecular weight of the oligomer is from 2000 to 5500 Daltons.