Photothermo-or thermo-graphic material

Details Photothermo-or thermo-graphic material Photothermo-or thermo-graphic material

2000-03-20

2001-11-06

Chea, Thorl (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Radiation sensitive product

Silver compound sensitizer containing

C430S523000, C430S531000, C430S619000

Reexamination Certificate

active

06312885

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to photothermographic or thermographic materials. Of the materials, the chief concern of the invention is a photothermographic material, particularly a photothermographic material which is inhibited from cracking upon heat development.
BACKGROUND OF THE INVENTION
Photothermographic materials have been proposed from of old. For instance, such materials are disclosed in U.S. Pat. Nos. 3,152,904 and 3,457,075, and
Thermally Processed Silver Systems
written by D. Klosterboer in the book entitled “Imaging Processes and Materials”, 8th ed., §9th, p 279, compiled by J. Sturge, V. Walworth & A, Shepp, published by Neblette in 1989. In general a photothermographic material has a photosensitive layer containing in a binder matrix a catalytic amount of photocatalyst (e.g., silver halide), a reducing agent, a reducible silver salt (e.g., an organic silver salt) and, if needed, a toning agent for controlling the tone of silver. After imagewise exposure, the photothermographic material is heated at a high temperature (e.g., at least 80° C.) to cause a redox reaction between silver halide or a reducible silver salt (functioning as an oxidizing agent), thereby forming a black silver image. The redox reaction is accelerated by the catalytic action of a latent image formed from the silver halide by exposure. Accordingly, the black silver image is formed in the exposed area.
The photosensitive layer of a photothermographic material has so far been formed using a coating solution containing polyvinyl butyral (PVB) as a binder in an organic solvent. However, the use of an aqueous solvent for the coating solution has been desired from the working viewpoint of preparation and application of a coating solution and the instrumental viewpoint. As a solution to such a problem, the method of coating an aqueous dispersion of styrene-butadiene copolymer for the formation of a photosensitive layer has been proposed in, e.g., JP-A-10-186567 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”). However, the protective layer made of gelatin has turned out to crack when it was provided on the photosensitive layer using the foregoing styrene-butadiene copolymer as binder and underwent heat development. This cracking problem is not produced in the case where the protective layer made of gelatin, cellulose or the like is provided on the photosensitive layer using PVB as binder.
SUMMARY OF THE INVENTION
An object of the present invention is to provide photothermographic or thermographic materials, particularly a photothermographic material, which are prevented from causing cracks upon heat development.
The aforementioned object of the present invention is attained by the following Embodiments (1) to (8):
(1) A photothermographic or thermographic material comprising a support having provided thereon or thereabove at least one image forming layer having its thermal expansion coefficient in the range of 1.0 to 1.5 and having provided on or above said at least one image forming layer a layer which has its thermal expansion coefficient of at least 0.9 and lower than 1.0 and comprises at least one kind of latex of polymer having a glass transition temperature of not higher than a heat development temperature, said layer which has its thermal expansion coefficient of at least 0.9 and lower than 1.0 being farther from the support than the at least one image forming layer.
(2) A photothermographic or thermographic material according to Embodiment (1), wherein the layer having its thermal expansion coefficient of at least 0.9 and lower than 1.0 is a surface protective layer.
(3) A photothermographic or thermographic material according to Embodiment (1) or (2), wherein the heat development temperature is from 90° C. to 130° C.
(4) A photothermographic or thermographic material according to Embodiment (1), (2) or (3), wherein the polymer comprises repeating units derived from ethylenically unsaturated monomeric units containing an active methylene group and monomeric units containing at least two ethylenically unsaturated groups per unit.
(5) A photothermographic or thermographic material according to Embodiment (4), wherein the ethylenically unsaturated monomeric units containing an active methylene group are represented by formula (I):
wherein R
1
represents a hydrogen atom, an alkyl group containing 1 to 4 carbon atoms or a halogen atom, L represents a single bond or a divalent linkage group, X represents an active methylene group selected from R
2
COCH
2
COO—, NC—CH
2
COO—, R
2
COCH
2
CO—, NC—CH
2
CO— or R
9
—CO—CH
2
CON (R
6
)—, R
2
represents an alky group containing 1 to 12 carbon atoms, an aryl group containing 6 to 20 carbon atoms, an alkoxy group containing 1 to 12 carbon atoms, an amino group or a substituted amino group containing 1 to 12 carbon atoms, R
6
represents a hydrogen atom or an alkyl group containing 1 to 6 carbon atoms, and R
9
represents a primary or secondary alkyl group containing 1 to 12 carbon atoms, an alkoxy group containing 1 to 12 carbon atoms, an amino group or a substituted amino group containing 1 to 12 carbon atoms, wherein the divalent linkage group as L is bonded to X in the form of an alkylene, aralkylene or arylene moiety thereof.
(6) A photothermographic or thermographic material according to any of Embodiments (1) to (5), wherein the image forming layer contains at least an organic silver salt and a reducing agent.
(7) A photothermographic or thermographic material according to any of Embodiments (1) to (6), wherein the image forming layer comprises a photosensitive silver salt.
(8) A photothermographic or thermographic material according to any of Embodiments (1) to (7), wherein the image forming layer comprises a binder having an equilibrium moisture content of at most 2 weight % under a condition of 25° C.-60% RH in a proportion of at least 50 weight % to the total binders contained therein.


REFERENCES:
patent: 3933508 (1976-01-01), Ohkubo et al.
patent: 5536627 (1996-07-01), Wang et al.
patent: 6140038 (2000-10-01), Ishizuka et al.

Affiliated with

Also associated with

Rating

Photothermo-or thermo-graphic material does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Photothermo-or thermo-graphic material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photothermo-or thermo-graphic material will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2613417