Stock material or miscellaneous articles – Composite – Of polyamide
Reexamination Certificate
2001-05-14
2003-02-11
Chen, Vivian (Department: 1773)
Stock material or miscellaneous articles
Composite
Of polyamide
C428S474400, C428S478200, C428S480000, C427S372200, C427S384000, C427S385500, C427S407100, C427S412100, C427S412500, C427S414000, C430S523000, C430S531000, C430S533000, C430S539000
Reexamination Certificate
active
06517947
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to light sensitive imaging elements in general and in particular to gelatin based subbing layers for improving the adhesion of photographic emulsion to a polyester support upon thermal annealing.
BACKGROUND
To adhere a photographic emulsion to a polyester support, either separate adhesive (subbing) layers or surface treatments are required. These adhesive systems must work both with raw and processed film in the dry state, and must also adhere when the film is wet during the development process. In addition, it is desirable to heat-treat or anneal the polyester support to impart the required physical properties, particularly to reduce core set to an acceptable level for recent applications such as small format films for use in smaller cameras. Furthermore, annealing the support with subbing or backing layers is advantageous for manufacturing efficiency.
A common subbing package uses materials such as poly(methyl acrylate-co-vinylidene chloride-co-itaconic acid) or poly(acrylonitrile-co-vinylidene chloride-co-acrylic acid) (disclosed in U.S. Pat. Nos. 3,201,249 and 3,143,421) as the first adhesive layer on the polyester support. This is then overcoated with a thin gelatin layer to form the adhesive system. To meet core-set criteria, an advanced photo system (APS) film uses a poly(ethylene naphthalate) support which is annealed at elevated temperatures. To reduce manufacturing costs, the subbing layers (vinylidene chloride polymer and gel sub) are applied to the support and it is then annealed. It has been observed that the wet adhesion properties of this system are significantly degraded after annealing.
To obtain acceptable adhesion of a silver-halide emulsion layer or a backing layer to a polyester support, a variety of methods have been used including, surface treatment of the support or application of adhesion promoting or subbing layers either prior to orientation and crystallization of the support or post-orientation. Adhesion of the anchoring, or subbing layer is promoted by a variety of methods, including the use of chlorine-containing copolymers, as described in U.S. Pat. Nos. 2,627,088; and 3,143,421. The application of the adhesive layer prior to the orientation and heat setting or crystallization of the polyester, and the addition of organic solvents which attack the polyester film surface is described in U.S. Pat. No. 3,501,301. In addition, a subsequent gelatin-containing layer is often required on the emulsion side of the support, prior to photographic emulsion coating, for adequate adhesion.
U.S. Pat. No. 4,407,939 (Fuji) describes the use of a gel sub layer between the subbing and emulsion. The gelatin used had been modified to increase the number of carboxylic acid groups, for example by reacting the gelatin with an acid anhydride. It does not describe the use of amine modified gels.
U.S. Pat. No. 5,219,992 (Kodak) describes the preparation and use of amine modified gelatin for differential hardening of multilayered photographic elements. It does not teach the use of these materials as annealable subbing layers.
EP #614,930-A1 (Agfa) describes the use of amine modified gelatins with increased reactivity to vinylsulphonyl hardeners for differential hardening in emulsions. It does not teach the use of these materials as annealable subbing layers.
Therefore it is the objective of this invention to provide a subbing system that provides good adhesion of the emulsion after annealing.
SUMMARY OF THE INVENTION
The present invention solves the problem discussed above by using a gelatin material is that has been derivatized to increase the number of reactive amine groups.
An imaging support comprising:
a polyester support;
an adhesive layer superposed to said support; and on the adhesive layer
an amine modified gelatin subbing layer, the amine modified gelatin having the formula:
wherein Gel is a gelatin polypeptide,
is a carbonyl group from a free carboxyl group in aspartic acid or a glutamic acid moiety in said polypeptide, and G is
wherein each R is independently hydrogen or a primary or secondary alkyl group of one to about four carbon atoms, n is a positive integer having a value of one to about four, and T is a hydrogen or
said modified gelatin being further characterized by having from 1% to about 40% of the free carboxyl groups in aspartic and glutamic acid moieties in said polypeptide being substituted with G-groups;
wherein said support has been annealed at a temperature that is 50 to 5° C. less than the glass transition temperature of the support for at least 6 hours.
Also disclosed is:
A method for preparing an imaging support comprising:
(a) providing a support;
(b) coating an adhesive layer onto said support;
(c) coating an amine modified gelatin subbing layer onto said adhesive layer wherein the gelatin has the formula:
wherein Gel is a gelatin polypeptide,
is a carbonyl group from a free carboxyl group in aspartic acid or a glutamic acid moiety in said polypeptide, and G is
wherein each R is independently hydrogen or a primary or secondary alkyl group of one to about four carbon atoms, n is a positive integer having a value of one to about four, and T is a hydrogen or
said modified gelatin being further characterized by having from 1% to about 40% of the free carboxyl groups in aspartic and glutamic acid moieties in said polypeptide being substituted with G-groups; and
(c) annealing the coating at a temperature that is 50 to 5° C. less than the glass transition temperature of the support for at least 6 hours.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is an imaging support which includes a base, preferably comprising polyester, most preferably comprising polyethylene naphthalate (PEN). An adhesive layer is superposed on the base and an amine modified gelatin-containing subbing layer is superposed on the adhesive layer. The imaging support is then annealed at a temperature that is 50 to 5° C. less than the glass transition temperature of the support for at least 6 hours.
In a further embodiment, a method for making an imaging support is disclosed.
The imaging support of this invention is suitable for use in various imaging elements including, for example, photographic, electrostatographic, photothermographic, migration, electrothermographic, dielectric recording, and thermal dye transfer imaging elements. Details with respect to the composition and function of this wide variety of imaging elements are provided in U.S. Pat. No. 5,719,016. Imaging elements that can be provided with a support in accordance with this invention can differ widely in structure and composition. For example, they can vary in regard to the type of support, the number and composition of the image forming layers, and the number and kinds of auxiliary layers included in the elements. The image forming layer(s) of a typical photographic imaging element includes a radiation sensitive agent (e.g., silver halide) dispersed in a hydrophilic water-permeable colloid. Suitable hydrophilic colloids include both naturally-occurring substances such as proteins, for example, gelatin, gelatin derivatives, cellulose derivatives, polysaccharides such as dextran, gum arabic, and the like; as well as synthetic polymers, for example, water-soluble polyvinyl compounds such as poly(vinylpyrrolidone), acrylamide polymers, and the like. A common example of an image-forming photographic layer is a gelatin-silver halide emulsion layer. In particular, the photographic elements can be still films, motion picture films, x-ray films, graphic arts films or microfiche. They can be black-and-white elements, color elements adapted for use in negative-positive process or color elements adapted for use in a reversal process.
Polymer film supports which are useful for the present invention include polyester supports such as -1,4-cyclohexanedimethylene tereplithalate, polyethylene 1,2-diphenoxyethane-4,4′-dicarboxylate, polybutylene tereplithalate, and polyethylene naphthalate and the like; and blends or laminates thereof. Particularly pr
Bauer Charles L.
Chen Janglin
Harbison Kenneth G.
Yau Hwei-Ling
Chen Vivian
Eastman Kodak Company
Wells Doreen M.
LandOfFree
Amine modified gelatin layer for improved adhesion of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Amine modified gelatin layer for improved adhesion of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Amine modified gelatin layer for improved adhesion of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3151323