# US 8,569,414 B2 · Polyvinyl alcohol resin composition and molded article thereof

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- Number: US 8,569,414 B2
- Document ID: US8569414B2
- Status: Granted
- Kind: B2
- Application number: 13/407,278
- Filed: 2012-02-28
- Published: 2012-06-21
- Granted: 2013-10-29
- Earliest claimed: 2009-09-03
- Assignees: The Nippon Synthetic Chemical Industry Co., Ltd.
- Applicants: Mitsuo Shibutani; Kazutoshi Tsuji; Kaoru Inoue; Norihito Sakai
- Inventors: Mitsuo Shibutani; Kazutoshi Tsuji; Kaoru Inoue; Norihito Sakai
- Web page: https://patentgrep.com/patent/US8569414B2

## CPC

- C08L 29/04: Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
- C08L 53/02: of vinyl-aromatic monomers and conjugated dienes
- C08L 53/025: {modified}
- C08L 2205/02: containing two or more polymers of the same C08L -group
- C08L 2205/03: containing three or more polymers in a blend
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

Disclosed is a polyvinyl alcohol resin composition capable of providing a melt-molded article with superior gas barrier properties and flex crack resistance. The resin composition comprises (A) a PVA resin having 1,2-diol unit in side chain thereof; and (B) a mixture of block copolymers each having an aromatic vinyl polymer block, and a conjugated diene polymer block and/or hydrogenated thereof, wherein the (B) mixture of block copolymers includes (B1) a block copolymer having no carboxyl group and (B2) a block copolymer modified with a carboxyl group-containing compound.

## Claims

### Claim 1

A polyvinyl alcohol resin composition comprising (A) a polyvinyl alcohol resin (abbreviated as PVA resin); and (B) a mixture of block copolymers, said block copolymers each containing a block of an aromatic vinyl polymer, and at least one of a block of a conjugated diene polymer and a hydrogenated block of the conjugated diene polymer,
wherein the (A) PVA resin contains a structural unit of the following formula (1), and wherein a weight ratio ((A)/(B)) of the contents of the (A) PVA resin to the (B) mixture of block copolymers is in the range of 90/10 to 75/25, and a ratio (ηA/ηB) of the melt viscosity ηA of the (A) PVA resin to the melt viscosity ηB of the (B) mixture of block copolymers is in the range of 1/3 to 3/1, and
wherein the (B) mixture of block copolymers includes (B1) a block copolymer having no carboxyl group and (B2) a block copolymer modified with a carboxyl group-containing compound, and a weight ratio ((B1)/(B2)) of the (B1) block copolymer to the (B2) block copolymer is in the range of 70/30 to 30/70:
wherein each of R1, R2 and R3 independently represents a hydrogen or an organic group, X represents a single bond or a linking chain, and each of R4, R5 and R6 independently represents a hydrogen or an organic group.

### Claim 2 (depends on 1)

The polyvinyl alcohol resin composition according to claim 1, wherein the (B2) block copolymer has an acid value of 0.5 to 20 mg CH3ONa/g.

### Claim 3 (depends on 2)

The polyvinyl alcohol resin composition according to claim 2, wherein the (B2) block copolymer has an acid value of 1.5 to 8 mg CH3ONa/g.

### Claim 4 (depends on 1)

The polyvinyl alcohol resin composition according to claim 1, wherein a weight ratio ((B1)/(B2)) of the contents of (B1) block copolymer to (B2) block copolymer is in the range of 40/60 to 60/40.

### Claim 5

A molded article obtained by melt molding a resin composition comprising
(A) a polyvinyl alcohol resin (abbreviated as PVA resin); and (B) a mixture of block copolymers, said block copolymers each containing a block of an aromatic vinyl polymer, and at least one of a block of a conjugated diene polymer and a hydrogenated block of the conjugated diene polymer, wherein the (A) PVA resin contains a structural unit of the following formula (1), and wherein a weight ratio ((A)/(B)) of the contents of the (A) PVA resin to the (B) mixture of block copolymers is in the range of 90/10 to 75/25, and a ratio (ηA/ηB) of the melt viscosity ηA of the (A) PVA resin to the melt viscosity ηB of the (B) mixture of block copolymers is in the range of 1/3 to 3/1, and wherein the (B) mixture of block copolymers includes (B1) a block copolymer having no carboxyl group and (B2) a block copolymer modified with a carboxyl group-containing compound, and a weight ratio ((B1)/(B2)) of the (B1) block copolymer to the (B2) block copolymer is in the range of 70/30 to 30/70:
wherein each of R1, R2 and R3 independently represents a hydrogen or an organic group, X represents a single bond or a linking chain, and each of R4, R5 and R6 independently represents a hydrogen or an organic group.