Polyvinylacetal resin for heat-developable photosensitive material and heat-developable photosensitive material

Patent metadata

Field	Value
Publication number	US-9951154-B2
Application number	US-201415124103-A
Country	US
Kind code	B2
Filing date	Mar 24, 2014
Priority date	Mar 24, 2014
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

A polyvinyl acetal resin for a heat-developable photosensitive material capable of preventing skinning in the coating process of the photosensitive layer of the heat-developable photosensitive material, preventing deterioration of image characteristics and coloration of the coating solution, and suppressing the occurrence of odor at the time of producing the heat-developable photosensitive material and heat development.
The polyvinyl acetal resin for a heat-developable photosensitive material used for a photosensitive layer of the heat-developable photosensitive material has a residual acetyl group content of 25 mol % or less, residual hydroxyl group content of 17-35 mol %, and polymerization degree of 200 to 3,000, and is obtained by an acetalization of a polyvinyl alcohol mixture containing polyvinyl alcohol resins having different polymerization degrees, wherein the content of the polyvinyl alcohol having a polymerization degree of 600 or less is 50 wt % or higher in the polyvinyl alcohol mixture.

First claim

The invention claimed is:

1. A polyvinyl acetal resin comprising
a residual acetyl group content of 25 mol % or less, residual hydroxyl group content of 17-35 mol %, and having a polymerization degree of 200 to 3,000,
wherein:
the polyvinyl acetal resin is obtained by an acetalization of a polyvinyl alcohol mixture containing polyvinyl alcohol resins having different polymerization degrees, and the polyvinyl alcohol mixture comprises 60% or more of polyvinyl alcohol having a polymerization degree of 600 or less, and
the polyvinyl acetal resin is capable of use as a photosensitive layer of a heat-developable photosensitive material.

2. The polyvinyl acetal resin according to claim 1 , comprising 60 ppm or less of 2-ethyl-2-hexenal.

3. The polyvinyl acetal resin according to claim 1 , comprising 100 ppm or less of each of alkali metal, alkaline earth metal, halide ions, sulfate ions and nitrate ions.

4. The polyvinyl acetal resin according to claim 1 , which is obtained by washing only particles which are able to pass through #60 mesh sieve after the acetalization.

5. The polyvinyl acetal resin according to claim 1 , which is granulated by compression granulation.

6. A heat-developable photosensitive material comprising a support and a photosensitive layer formed on the support, wherein the photosensitive layer contains the polyvinyl acetal resin according to claim 1 , organic silver salt, photosensitive silver halide and silver ion reducing agent.

Assignees

• Sekisui Chemical Co Ltd

Inventors

• Yamauchi Kenji
• Miyai Jiro
• Naruwaki Shogo
• Maeda Takayuki

Classifications

• C09D5/32

  Radiation-absorbing paints {(protection against X-, gamma- or corpuscular radiation G21F)} · CPC title

• G03C1/49863

  Inert additives, e.g. surfactants, binders · CPC title

• C08F8/28 Primary

  Condensation with aldehydes or ketones · CPC title

• C09D5/26

  Thermosensitive paints · CPC title

• C09D129/14

  Homopolymers or copolymers of acetals or ketals obtained by polymerisation of unsaturated acetals or ketals or by after-treatment of polymers of unsaturated alcohols · CPC title