JPH04369639A - Image forming material - Google Patents

Abstract

PURPOSE:To obtain the image forming material having an excellent preservable property, high UV color developing density and high visible light fixing performance. CONSTITUTION:A photosensitive layer which is a photosensitive layer contg. (a) a photooxidizing agent which forms an oxidative material by irradiation with UV rays, (b) a dye leuco substance which develops a color by the oxidative material, (c) a photoreducing agent which forms a reducing agent by irradiation with visible light, (d) a hydrogen donator which supplies hydrogen to this photoreducing agent, (e) a binder, and (f) a plasticizer and contains the plasticizer and hydrogen donator at a relatively high ratio to the ratio of the binder is provided on a base material. A light transmissible layer is laminated on this photosensitive layer. The relatively large amt. of the plasticizer and the hydrogen donator are incorporated into the binder, by which the high UV color developing density and the high visible light fixing performance are obtd. In addition, sticking is eliminated and the preservable property is enhanced by the light transmissible layer.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming material that develops color when irradiated with ultraviolet light and is fixed when irradiated with visible light.

0002

[Prior Art and Problems to be Solved by the Invention] Many studies have been conducted on image forming materials that develop color by irradiation with ultraviolet light and are fixed by irradiation with visible light (Japanese Patent Publication No. 19161-1916, Japanese Patent Publication No. 47 -17855, JP-A-47-12879, etc.). These photosensitive compositions include a photooxidizing agent that generates an oxidizing substance when irradiated with ultraviolet light, a leuco dye that develops color due to the oxidizing substance generated by irradiation with ultraviolet light, and a photoreducing agent that generates a reducing agent when irradiated with visible light. It consists of a hydrogen donor that supplies hydrogen to a photoreducing agent, and in some cases a binder, a plasticizer, etc., which is dissolved in a solvent, applied to paper, plastic film, etc., and dried to form an image forming material. However, the image-forming material obtained from this method has low contrast because both the ultraviolet light coloring sensitivity and the visible light fixing sensitivity are insufficient, and in particular, a fairly long exposure time is required to obtain sufficient fixing.

[0003] To improve this drawback, the Special Publication Act of 1983
There have been reports such as No. 2099, but this increases the prescription cost because it uses special substances. In addition, all of the image forming materials reported above have poor storage stability when used as raw samples, and when stored for a long period of time, there are drawbacks such as a marked decline in color density and fixing performance.

[0004] The present invention was made to eliminate the above-mentioned conventional drawbacks, and it has excellent preservation of raw samples,
Another object of the present invention is to provide an image forming material having extremely high ultraviolet light coloring density and extremely sensitive visible light fixing performance.

[0005]

[Means for Solving the Problems] The image forming material of the present invention that achieves the above objects comprises a base material, and (a) a light beam that generates an oxidizing substance by irradiation with ultraviolet light, which is laminated on the base material. an oxidizing agent, (b) a leuco dye that develops color due to the oxidizing substance generated by this ultraviolet light irradiation, (c) a photoreducing agent that generates a reducing agent by visible light irradiation, and (d) supplying hydrogen to this photoreducing agent. A photosensitive layer containing a hydrogen donor, (e) a binder, and a light-transmitting layer laminated on the photosensitive layer, and the photosensitive layer optionally further contains (f) a plasticizer, The sum of hydrogen donor and plasticizer is 0.5 parts by weight of binder.
Parts by weight or more.

[0006] The base material is not particularly limited and may be one commonly used for graphic art, and examples include paper, triacetyl cellulose film, polyester film, and glass. The (a) photooxidizing agent and (b) leuco dye in the photosensitive layer are components that cause the photosensitive layer to develop color upon irradiation with ultraviolet light, and as such a photooxidizing agent, hexaallylbiimidazole is preferable. Particularly preferred hexaallylbiimidazoles include 2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole and 2,2'-bis(o-chlorophenyl)-4,
4',5,5'-tetrakis(m-methoxyphenyl)
Examples include biimidazole.

[0007] Also suitable as the leuco dye are aminotriarylmethanes in which at least two allyl groups have an alkyl group, an alkoxy group, or a halogen atom ortho to the methane carbon. Particularly preferred examples include bis(4-diethylamino-o-tolyl)phenylmethane and tolyl(4-diethylamino-o-tolyl)methane.

The photoreducing agent (c) and the hydrogen donor (d) in the photosensitive layer are components that fix images formed by irradiation with ultraviolet light.
Quinones that absorb in the region of ~500 nm are suitable. Particularly preferred is 9,10-phenanthrenequinone. Furthermore, as the hydrogen donor that supplies hydrogen to the photoreducing agent, organic compounds whose hydrogen atoms are likely to become active are suitable, and triethanolamine triacetate is particularly preferred.

(e) Examples of the binder include resins such as ethyl cellulose, cellulose acetate, polyvinyl butyral, cellulose acetate butyrate, and cellulose acetate propionate, with cellulose acetate butyrate being particularly preferred. (f) Although the plasticizer is not an essential component, by including it in a predetermined amount in the photosensitive layer together with the hydrogen donor, the coloring sensitivity can be improved.
Color density and fixing sensitivity can be improved. This is thought to be because reactions for color development and fixing proceed rapidly by including such sticky components in excess. Such plasticizers include N-
Examples include ethyl-P-toluenesulfonamide,
The amount added is such that the sum of the hydrogen donor and plasticizer is 0.5 parts by weight or more, preferably 0.8 parts by weight or more, per 1 part by weight of the binder. By adding the hydrogen donor and plasticizer in a relatively excessive amount to the binder in this way, coloring sensitivity, coloring density, and fixing sensitivity can be significantly increased. However, in this case, the coating film becomes too sticky and cannot be used practically, so it is essential to laminate a light-transmitting layer on the photosensitive layer.

The light-transmitting layer makes the image-forming material of the present invention practical and improves its long-term storage stability even when the photosensitive layer is highly sticky due to its composition as described above. The light-transmitting layer used is one that does not inhibit the color development of the photosensitive layer by ultraviolet light and the fixation by visible light, that is, one that transmits light with a wavelength of about 320 nm to 520 nm and has excellent weather resistance. . Examples include polyester film, polyvinyl chloride film, glass, and the like. Also, instead of something like the above,
A coating film obtained by coating with polyester resin, polyvinyl chloride resin, etc. may also be used.

As explained above, the image-forming material of the present invention consists of three layers: a base material, a photosensitive layer, and a light-transmitting layer.
After coating the above-mentioned substances (a) to (f) dissolved in a suitable organic solvent on the base material and drying to form a photosensitive layer,
It is manufactured by further laminating a light-transmitting layer. According to the present invention, since a light-transmitting layer is further laminated on the photosensitive layer coating, stickiness of the coating does not become a problem in practical use, and good coloring sensitivity, coloring density, and fixing performance can be achieved. The storage performance is improved, and the material also has solvent and chemical resistance.

0012

[Examples] The present invention will be explained below with reference to Examples. Example 1 A photosensitive solution having the following composition was prepared. cellulose acetate butyrate
3.0g N-ethyl-P-toluenesulfonamide
0.7g Tris(4-diethylamino-O-
tolyl)methane 0.07g 2,2'-bis(O-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole
0.15g P-
Toluenesulfonic acid monohydrate
0.2g 9, 10, phenanthrenequinone
0.03g Triethanolamine triacetate 0.8g Methyl ethyl ketone
12g toluol

6g of this solution was applied onto a 100μm polyester film using a wire bar, and then heated in an oven at 100℃ for 90℃.
After drying for a few seconds, a photosensitive layer having a thickness of about 10 μm was obtained. Furthermore, a 50 μm polyester film was laminated on this coating film using a laminator to obtain an image forming material. Comparative Example 1 is one in which polyester film is not laminated, and both are heated at 40°C.
The relationship between the number of storage days and image performance was investigated. In addition, image performance is determined by the image density (D1) when exposed for 40 seconds with a high-pressure mercury lamp using a filter that cuts out wavelengths of 400 nm or more, and the image density (D1) when exposed for 60 seconds with a high-pressure mercury lamp using a filter that cuts out wavelengths of 400 nm or less, and further under the conditions of D1. The image density (D2) upon exposure was measured. The results are shown in Table 1.

[0013]

[Table 1]

As is clear from Table 1, when the photosensitive layer was laminated with a polyester film, the image performance did not deteriorate even after storage, and good color development and fixation were exhibited. Examples 2 and 3 Photosensitive solutions having the compositions shown in Table 2 were prepared.

[0015]

[Table 2]

[0016] In Table 2, the numbers indicate the content of components A to I (
g), A represents cellulose acetate butyrate (
B is N-ethyl-P-toluenesulfonamide (plasticizer), C is tris (4-diethylamino-O-
tolyl)methane, D is 2,2'-bis(O-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2
'-biimidazole, E is P-toluenesulfonic acid monohydrate, F is 9, 10, phenanthrenequinone, G is triethanolamine triacetate (hydrogen donor), H is methyl ethyl ketone, and I is toluol. J is “(
B content + G content)/A content.

These photosensitive solutions were applied onto a 100 μm polyester film using a wire bar, and then dried in an oven at 100° C. for 90 seconds to obtain a photosensitive layer of about 10 μm. Further, a 50 μm polyester film was laminated using a laminator to obtain an image forming material. Samples of this image forming material were each exposed to light under the following conditions, and the image densities (D1, D2) were measured. That is, D1 is 400
Image density when exposed for 30 seconds with a high-pressure mercury lamp using a filter that cuts wavelengths of 400 nm or more, D2 is 60
This is the image density when exposed for seconds and further exposed under the conditions of D1. The results are shown in Table 3.

[0018]

[Table 3]

Note that tack in Table 3 represents the stickiness of the photosensitive layer, with no stickiness being rated ◯, some being slightly tack being △, and strong stickiness being rated ×. As is clear from Table 3, the one containing excess hydrogen donor (G) and plasticizer (B) with respect to binder resin (A) (Example 3) had good color density,
It showed fixing performance. Although Examples 2 and 3 are sticky compared to Comparative Examples, this stickiness does not pose a problem in practical use due to the lamination of a light-transmitting layer, and rather the storage stability is improved by the light-transmitting layer.

[0020]

As is clear from the above examples, according to the present invention, an ultraviolet coloring and visible light fixing image forming material with very high sensitivity and contrast can be obtained at low cost. In addition, this image-forming material has excellent storage stability in the dark in an unexposed state compared to conventional materials, and the material itself has excellent solvent and chemical resistance, making it extremely useful in practical terms. .

Claims (2)

[Claims] Claims: 1. A base material, and (a) a photo-oxidizing agent that generates an oxidizing substance upon irradiation with ultraviolet light, (b) a leuco dye that develops color due to the oxidizing substance, and (c) ) a photoreducing agent that generates a reducing agent upon irradiation with visible light, (d) a hydrogen donor that supplies hydrogen to the photoreducing agent, (e) a photosensitive layer containing a binder, and a photosensitive layer laminated on the photosensitive layer. An image forming material comprising a transparent layer. 2. A base material, and (a) a photo-oxidizing agent that generates an oxidizing substance upon irradiation with ultraviolet light, (b) a leuco dye that develops color due to the oxidizing substance, and (c) ) a photoreducing agent that generates a reducing agent upon irradiation with visible light; (d) a hydrogen donor that supplies hydrogen to the photoreducing agent; (e) a binding agent;
(f) The photosensitive layer includes a photosensitive layer containing a plasticizer and a light-transmitting layer laminated on the photosensitive layer, and the photosensitive layer has a structure in which the sum of the plasticizer and the hydrogen donor is 1 part by weight of the binder. An image forming material characterized in that the amount is 0.5 part by weight or more.