# US 10,766,983 B2 · PVOH dispersant for VCM polymerization

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,766,983 B2
- Document ID: US10766983B2
- Status: Granted
- Kind: B2
- Application number: 15/555,856
- Filed: 2016-03-04
- Published: 2018-02-15
- Granted: 2020-09-08
- Earliest claimed: 2015-03-05
- Assignees: Sekisui Specialty Chemicals America, LLC
- Applicants: Sekisui Specialty Chemicals America, LLC
- Inventors: K. Van Phung; Yohei Nishimura; Tsutomu Ando; Hidehiro Yamaguchi; Joseba Inaki Iragorri; Kaustubh Ghorpade
- Web page: https://patentgrep.com/patent/US10766983B2

## CPC

- C08F 116/06: Polyvinyl alcohol {; Vinyl alcohol}
- C08F 2/20: with the aid of macromolecular dispersing agents
- C08F 14/06: Vinyl chloride
- C08F 114/06: Vinyl chloride
- C08F 216/06: Polyvinyl alcohol {; Vinyl alcohol}
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS

## Abstract

Dispersing agents useful in a suspension polymerization process may be formed based on polyvinyl alcohols and processes discloses herein. The dispersing agent may include, for example: a polyvinyl alcohol having a degree of hydrolysis in the range from 60 to 80 mol %; an absorbance of not less than 0.3 measured at a wavelength of 320 nm with respect to a 0.1 wt % aqueous solution of the polyvinyl alcohol; a block character of remaining ester groups in the range from 0.4 to 0.5; and a cloud point in the range from 35° C. to 50° C. measured with respect to a 1 wt % aqueous solution of the polyvinyl alcohol. Carbonyl groups are theorized to be present along the polymer chain, which may be quantified by 1-H NMR spectra peaks.

## Claims

### Claim 1

A dispersing agent useful in a suspension polymerization process, the dispersing agent comprising:
a polyvinyl alcohol formed by a process comprising:
polymerizing a vinyl ester monomer to form a polyvinyl ester;
partially hydrolyzing the polyvinyl ester to produce a partially hydrolyzed polyvinyl ester;
heat treating the partially hydrolyzed polyvinyl ester to form the polyvinyl alcohol;
wherein the partially hydrolyzing step comprises contacting the polyvinyl ester with an alkali hydroxide and with hydrogen peroxide;
the polyvinyl alcohol having:
a degree of hydrolysis in the range from 60 to 80 mol %;
an absorbance of not less than 0.3 measured at a wavelength of 320 nm with respect to a 0.1 wt % aqueous solution of the polyvinyl alcohol;
a block character of remaining ester groups in the range from 0.4 to 0.5;
a cloud point in the range from 35° C. to 50° C. measured with respect to a 1 wt % aqueous solution of the polyvinyl alcohol; and
carbonyl groups distributed along the length of the polymer chain;
wherein the polymerizing step is preformed in the absence of both an added chain transfer agent and an added comonomer.

### Claim 2 (depends on 1)

The dispersing agent of claim 1, wherein the polyvinyl alcohol comprises a partially hydrolyzed polyvinyl acetate having a general formula represented by:
where
Ac represents an acethyl group; and
x, y, and z represent a relative mole fraction of the respective groups and are each between 0 and 1.

### Claim 3 (depends on 1)

The dispersing agent of claim 1, the polyvinyl alcohol having a degree of hydrolysis in the range from 69 to 75 mol %.

### Claim 4 (depends on 1)

The dispersing agent of claim 1, the polyvinyl alcohol having a viscosity in the range from about 4 cP to about 10 cP, as measured using a 4 wt % aqueous solution of the polyvinyl alcohol.

### Claim 5 (depends on 1)

The dispersing agent of claim 1, the polyvinyl alcohol having a viscosity in the range from about 4.5 cP to about 6.5 cP, as measured using a 4 wt % aqueous solution of the polyvinyl alcohol.

### Claim 6 (depends on 1)

The dispersing agent of claim 1, wherein the vinyl ester monomer comprises vinyl acetate monomer.

### Claim 7 (depends on 1)

The dispersing agent of claim 1, wherein the heat treating step is performed in the absence of an added salt or catalyst.

### Claim 8 (depends on 1)

The dispersing agent of claim 1, wherein the polyvinyl alcohol has a 1H-NMR spectra comprising:
an integral value (a), defined as the area of a peak proximate 5.52+/−0.02 ppm, in the range from about 0.05 to about 0.15 pph CH, CH being defined as the area of a peak proximate 3.85+/−0.02 ppm; and
an integral value (b), defined as the area of a peak proximate 5.88+/−0.02 ppm, in the range from about 0.1 to about 0.4 pph CH.

### Claim 9 (depends on 8)

The dispersing agent of claim 8, wherein the polyvinyl alcohol has a 1H-NMR spectra comprising:
an integral value (c), defined as the area of a peak proximate 6.53+/−0.02 ppm, in the range from about 0.7 to about 0.8 pph CH; and
an integral value (d), defined as the area of a peak proximate 7.40+/−0.01 ppm, in the range from about 0.2 to about 0.3 pph CH.

### Claim 10 (depends on 1)

A dispersion comprising the dispersing agent of claim 1 and water.

### Claim 11 (depends on 10)

The dispersion of claim 10, further comprising at least one of a vinyl monomer and an initiator.

### Claim 12 (depends on 10)

The dispersion of claim 10, wherein the vinyl monomer comprises vinyl chloride monomer.

### Claim 13 (depends on 1)

A process for producing a polyvinyl chloride, the process comprising:
admixing the dispersing agent of claim 1 with a vinyl chloride monomer and water to form a suspension; and
polymerizing the vinyl chloride monomer to form a polyvinyl chloride.

### Claim 14 (depends on 13)

The process of claim 13, wherein the suspension further comprises a secondary dispersant.