JPH0677152B2 - Photosensitive material - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a photosensitive recording material using microcapsules (hereinafter abbreviated as photosensitive material). In particular, it relates to a photosensitive material using microcapsules containing a specific combination of core substances and having a specific particle size.

[Prior Art] There have been many studies on recording systems using capsules, and many systems such as pressure-sensitive recording systems and heat-sensitive recording systems have been developed.

Various forms have been proposed, for example, U.S. Pat.
507, 2,730,456, 2,730,457, 3,418,250
No. 3,432,327 and the like.

These prior arts have a drawback that recording corresponding to pressure or heat can be obtained, but recording corresponding to light as described in the present invention cannot be obtained.

Also, it has been attempted to form a capsule wall of a photosensitive polymer into a photosensitive recording material. However, as is well known, the capsule wall is very thin, 100 μm or less, and since it is necessary to have a certain level of wall strength, it is necessary to change the strength of the capsule wall by using a crosslinking reaction. The recording material utilizing the difference in strength basically has a difficult problem.

[Summary of the Invention] The present invention focuses on these drawbacks and improves them. That is, the object of the present invention is to include a vinyl compound having a plurality of acryloyl groups and a photopolymerization initiator as a core substance on a support, and having an average particle diameter of 20 μm or less (pressure rupture property). Another object of the present invention is to provide a photosensitive material carrying microcapsules fixed to a support with a binder or a protective agent.

In the photosensitive material of the present invention, after the energy for curing the vinyl compound is applied in an image form, the core substance of the uncured microcapsules is transferred to the image receiving sheet (preferably, the photosensitive material is applied in an overlapping manner with the image receiving sheet). It is preferably used in an image forming method characterized by forming an image on an image receiving sheet (by a core substance released from a microcapsule which is pressed and destroyed).

The capsules contained in the photosensitive material of the present invention are cured by exposure to the entire capsules in that portion, and the difference from the uncured capsules in the unexposed portion becomes very large. For example, when imagewise exposed and then transferred to an appropriate support, the core substance does not transfer from the cured portion of the capsule.

As typical compounds of the vinyl compound having a plurality of acryloyl groups of the present invention, polyethylene glycol diacrylate, pentaerythritol triacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, hexanediol diacrylate, 1 , 2
-Butanediol diacrylate, tetrakis (β-hydroxyethylethylenediamine) tetraacrylate, reaction product of epoxy resin and acrylic acid, acid condensate of pentaerythritol and acrylic acid, condensate of maleic acid and diethylene glycol and acrylic acid, etc. There is.

These may be used in combination according to the purpose.

Examples of photopolymerization initiators include aromatic ketones, quinone compounds, and nitro compounds.

Specific examples include benzoquinone, phenanthrenequinone, naphthoquinone, diisopropylphenanthrenequinone, benzoin butyl ether, benzoin, furoin butyl ether, Michler's ketone, Michra-thioketone, fluorenone, trinitrofluorenone, β-benzoylaminonaphthalene, and the like.

These are 0.1% to 8% by weight with respect to the vinyl compound.
Added to a degree.

A solvent may be used together when the vinyl compound and the photopolymerization initiator are encapsulated.

As a method of encapsulating these compounds, a known encapsulation method can be applied. For example, as a method for producing capsules, U.S. Pat.Nos. 2,800,457 and 2,800,458 utilizing coacervation, British Patent 990,
No. 443, a method by the interfacial polymerization method found in U.S. Pat. There is polymerization etc. In particular, the effect is large when the method by polymer precipitation and the encapsulation method by polymerization of the reactant from the inside of the oil droplet are used. That is, it is possible to obtain a capsule having a uniform particle size, which is preferable as a photosensitive material, in a short time. The particle size of the microcapsules of the present invention is 20 μm or less, particularly in view of handleability during storage. It is more preferably 10 μm or less. Also,
From the viewpoint of the ease of transfer, it is desirable that the thickness be 1 μm or more.

As the support, a plastic film, synthetic paper, aluminum plate, paper or the like is used.

When applied to the support, a binder such as PVA or LATEX, a protective agent such as starch, etc. are used, whereby the microcapsules are fixed to the support, and various additives conventionally used in recording systems, Binders, antioxidants, anti-smudge agents, surfactants and coating methods, well known for use, etc., U.S. Patent Nos. 2,717,375, 3,625,736, British Patent 1,232,347,
JP-A-50-44012, 50-50112, 50-127718, 5
0-30615, U.S. Pat. Nos. 3,836,383, and 3,846,331 are disclosed, and these techniques can be used.

Examples will be given below in order to further clarify the effects of the present invention.

The developer coated sheet used in the examples was prepared by the following method.

That is, 100 g of sulfuric acid-treated acidic clay was dispersed in 280 g of water containing 6 g of 40% caustic soda aqueous solution with a homogenizer, and then 50 g of water containing 10% of sodium salt of casein as a binder.
And 30 g of styrene-butadiene latex (trade name: Dow Latex 626, manufactured by Dow Chemical Co.) were added to obtain a developer coating solution. This developer coating solution was applied onto a polyethylene terephthalate film subjected to corona discharge treatment so that the coating amount was 7 gr / m ^2, and dried to obtain a developer coated sheet.

Moreover, in an Example, a part shows a weight part.

[Example 1] (1) Preparation of microcapsules 23 g of pentaerythritol tetraacrylate, 2 g of methyl ethyl ketone and 0.2 g of phenanthrenequinone were weighed and dissolved in an ultrasonic disperser. To this was added and dissolved 8.7 parts of tolylene diisocyanate and trimethylolpropane 3: 1 adduct and 0.1 part of ethyleneamine propylene oxide 1: 4 adduct. This solution was emulsified and dispersed in a solution in which 2.6 parts of polyvinyl alcohol was dissolved in 29 parts of water at 20 ° C. to obtain 6 μm.
And Then, after emulsifying, add 89 parts of water and stir at 70 ° C.
The mixture is warmed up to 1 hour, stirred for 1 hour and cooled. The microcapsule dispersion thus obtained can be taken out as powder by a spray drying method.

(2) Preparation of Photosensitive Material Carrying Microcapsules The microcapsule dispersion thus obtained was applied onto a polyethylene terephthalate film subjected to corona discharge treatment so that the coating amount was 7 gr / m ^2, and the present invention was dried. To obtain a photosensitive material (microcapsule coated sheet).

The microcapsule coated sheet was imagewise exposed with a mercury lamp (exposure for 3 minutes using an Atlas ultraviolet irradiation device). In the exposed part, the core material of the capsule was completely cured.

This image-wise exposed sheet was superposed on the developer-coated sheet, which was previously placed, and was pressed at a pressure of 150 kg / m ² for 10 seconds. The capsules in the unexposed area were destroyed and transferred onto the color developer coated sheet. This is sprayed with an ethyl acetate solution of crystal violet lactone, so the transferred part does not develop color and is not transferred (corresponding to the exposed and hardened part).
It was also confirmed from the fact that the part of the part produced a clear blue color image.

Example 2 In Example 1, pentaerythritol tetraacrylate (23 g) was replaced with trimethylolpropane triacrylate (20 g).
g, methacryloxyethyl cinnamate 3 g, and 0.2 g of benzylphenylimidazole were changed to obtain a photosensitive material in the same manner. In this case, a clearer image than the image obtained in Example 1 was obtained.

Example 3 A microcapsule dispersion according to the present invention was prepared in the same manner as in the preparation of the microcapsule dispersion of Example 1, except that the stirring strength during emulsion dispersion was reduced and the particle size of the microcapsules was set to 15 μm. did. Using this microcapsule dispersion, a photosensitive material according to the present invention was prepared in the same manner as in Example 1. Then, an image forming method similar to that of Example 1 was carried out using this, and evaluated. As a result, a clear image was obtained on the color developer coated sheet.

Comparative Example 1 A microcapsule dispersion was prepared in the same manner as in the preparation of the microcapsule dispersion of Example 1, except that pentaerythritol tetramethacrylate was used instead of pentaerythritol tetraacrylate.

Next, using this microcapsule dispersion, Example 1
A photosensitive material was prepared in the same manner as in. Then, an image forming method similar to that of the above-mentioned Example 1 was carried out using this photosensitive material. When the developer coated sheet after image formation was sprayed with an ethyl acetate solution of cryltal violet lactone, no color was developed on the entire surface and no image was obtained. However, an image was obtained when an image was formed by increasing the light quantity at the time of exposure to 10 times.

From the above, it can be seen that higher sensitivity is obtained when an acrylate compound is used as the monomer than when a methacrylate compound is used.

[Comparative Example 2] A microcapsule dispersion was prepared in the same manner as in the preparation of the microcapsule dispersion of Example 1, except that the stirring strength during emulsion dispersion was further reduced and the particle size of the microcapsules was 25 µm. A photosensitive material was prepared using this microcapsule dispersion in the same manner as in Example 1, but the coated surface was slightly inferior in smoothness. Further, the photosensitive material thus produced is very susceptible to scratches, and when the image forming method similar to that in Example 1 is carried out, the color-developed portion of the obtained image is likely to be scratched. Many possible unevenness (spots) occurred and the image quality was poor.

Example 4 and Comparative Example 3 Microcapsules were prepared in the same manner as in Example 1, except that the following compound was used instead of pentaerythritol tetraacrylate (A4).

Compounds with multiple acryloyl groups (A3) Pentaerythritol triacrylate (B2) Polyethylene glycol diacrylate (C3) Trimethylolpropane triacrylate (C2) Trimethylolpropane diacrylate (D2) Hexanediol diacrylate (E2) 1,2 -Butanediol diacrylate (F4) Tetrakis (β-hydroxyethylethylenediamine) tetraacrylate Compound with one acryloyl group (A1) Pentaerythritol monoacrylate (B1) Polyethylene glycol monoacrylate (C1) Trimethylolpropane monoacrylate (D1) Hexanediol monoacrylate (E1) 1,2-butanediol monoacrylate (F1) Tetrakis (β-hydroxyethylethylenediamine) monoacrylate Compounds with multiple acryloyl groups (a3) Pentaerythritol trimethacrylate (b2) Polyethylene glycol dimethacrylate (c3) Trimethylolpropane trimethacrylate (c2) Trimethylolpropane dimethacrylate (d2) Hexanediol dimethacrylate (e2) 1,2 -Butanediol dimethacrylate (f4) tetrakis (β-hydroxyethylethylenediamine) tetramethacrylate A photosensitive material was prepared in the same manner as in Example 1 using the microcapsules prepared as described above, and exposure, pressurization and spraying of crystal violet lactone were performed. Was done. The image obtained on the image receiving sheet was visually observed. The results are shown in Table 1 below.

For reference, Table 1 also shows the results of pentaerythritol tetraacrylate (A4) of Example 1 and pentaerythritol tetramethacrylate (a4) of Comparative Example 1.

As is clear from the results shown in Table 1, when the compounds having a plurality of methacryloyl groups (a4 to f4) were used as vinyl compounds, the compounds having a plurality of acryloyl groups (A4 to F4) were used as vinyl compounds. As compared with the case, the sensitivity was remarkably low, and it was confirmed that image formation was difficult with the exposure amount of Example 1. In order to obtain a clear image by using a compound having a plurality of methacryloyl groups (a4 to f4) as a vinyl compound, the exposure amount was 10 to 50 times that of Example 1.

In addition, when a compound having one acryloyl group (A1 to F1) is used as a vinyl compound, a sharp image is obtained as compared with a compound having a plurality of acryloyl groups (A4 to F4) being used as a vinyl compound. It was also confirmed that the degree was extremely low. Compounds having one acryloyl group (A1 to F
In order to obtain a clear image by using 1) as a vinyl compound, an exposure amount of 5 times or more that of Example 1 was required.

Claims (1)

[Claims] 1. A binder or a protective agent containing, on a support, a microcapsule containing a vinyl compound having a plurality of acryloyl groups and a photopolymerization initiator as a core substance and having an average particle size of 20 μm or less and having a pressure-breaking property. A photosensitive recording material which is carried in a state of being fixed to a support.