JP2656269B2 - Image forming material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image forming material capable of distinguishing an image area from a non-image area by a difference in curability in a microcapsule caused by exposure. Things.

(Prior Art) As an example of an image forming material using a microcapsule containing a photosensitive composition, US Pat. No. 3,219,446 discloses a transfer using a microcapsule containing a black dye and a crosslinkable polymer or a polymerizable monomer. An image forming method is disclosed. The capsule layer is exposed imagewise to bring the liquid in the exposed capsule into a rigid state. This is superimposed on the image receiving sheet and a pressure is applied to transfer an image corresponding to the exposure onto the image receiving sheet. JP-A-57-17
No. 9836, No. 57-197538, No. 58-16886, No. 58
No. 23024 and No. 23025 show that a sheet coated with a vinyl compound or a photocurable resin and microcapsules containing a photopolymerization initiator and a dye precursor is exposed, and then overlaid with an image receiving sheet coated with a color developer. An image corresponding to the exposure can be obtained by pressurizing the whole or by exposing a sheet in which the microcapsules and the developer are present on the same surface and then pressurizing alone. Such an image forming method has a feature that a high-quality image can be obtained by dry simple processing. However, the sensitivity to light is still insufficient. Therefore, it is necessary to lengthen the exposure time to cure the microcapsules.

(Problems to be Solved by the Invention) The present invention is an improvement over the disadvantages of the above technology. That is, an object of the present invention is to provide an image forming material using a microcapsule containing a photosensitive composition, which has high sensitivity to light, can record in a short exposure time, and can obtain an image by a simple process.

(Means for Solving the Problems) The present invention relates to an image forming material comprising a support and at least a photosensitive layer containing a microcapsule mainly containing a photopolymerizable compound and a color image forming agent. An image forming material characterized in that a layer containing a specific light-reflective compound is applied between a layer and a support.

The image forming material of the present invention has improved sensitivity by using a specific light reflective compound. This is because when the image forming material is exposed imagewise, the inside of the microcapsule is hardened by the irradiation light. Furthermore, the light partially transmitted through the microcapsules is reflected by a specific light reflective compound,
It reenters the microcapsules and contributes to curing. For this reason, when light of a fixed irradiation amount was exposed, more microcapsules could be efficiently cured.

The light reflective compound used in the image forming material of the present invention is alumina, magnesium oxide, magnesium carbonate, barium sulfate, zircon oxide or a condensable triazine compound, and two or more of them can be used in combination.

Examples of the photopolymerizable compound used in the present invention include polymerizable compounds having one or more acryloyl groups, allyl groups, vinyl groups, vinylidene groups, epoxy groups, and the like, and oligomers and polymers thereof. These can be used either as liquids or solids. For example, there are acrylic acid and its derivatives, methacrylic acid and its derivatives, styrene and its derivatives, vinyl ethers, vinyl esters, N-vinyl heterocycles, and the like. Specific examples include butyl acrylate, methoxyethyl acrylate, and methoxypolyethylene. Glycol acrylate, dimethylaminoethyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, ethylene glycol diacrylate, polyethylene glycol diacrylate,
1,6-hexane glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, 2-ethylhydroxy methacrylate, butyl methacrylate, methoxyethyl methacrylate, methoxypolyethylene glycol methacrylate, dimethylaminoethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate , Ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,6-hexane glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol methacrylate,
Acrylic amide, methacrylic amide, acrylic anilide, methacrylic anilide, styrene, vinyl toluene, chloromethyl styrene, 1-vinyl-2-methylimidazole, N-vinyl carbazole, vinyl benzyl ether, m-xylene acrylamide, hexamethylene There are bisacrylamide, 2-hydroxy-3-chloropropyl methacrylate, 2-hydroxy methacrylate and the like. Further, compounds in which a vinyl group is introduced into the skeleton of a color image forming agent, for example, a dye, a pigment, a leuco dye, etc., can also be used as the photopolymerizable compound.

The color image forming agents used in the present invention are classified into those which are originally colored and those which are colored by reacting with other compounds which are originally colorless. The former includes colored dyes and pigments. For example, monoazo-based, disazo-based, metal complex salt type monoazo-based, anthraquinone-based, phthalocyanine-based, triallylmethane-based colored dyes, etc., and represented by a color index number, 11020, 12055, 12700, 12010,
12715, 26125, 61565, 61100, 61525, 74350, 12195, 5
0415 etc.

Colored pigments include zinc white, basic lead sulfate, carbon black, aniline black, graphite, titanium yellow, Hansa yellow, permanent yellow, permanent orange, benzidine orange, iron oxide, amber, red bengala, antimony red, lake red, and cobalt. Blue, navy blue, Victoria Blue Lake, chrome green, cobalt green, copper phthalocyanine and the like.

These are used after being dissolved or dispersed in a photopolymerizable compound or the like.

As the latter, generally, two kinds of compounds, which are colorless or pale, come into contact with each other to produce a colored substance by a reaction such as acid-base, oxidation-reduction, coupling or chelation. For example, a combination of a color former (dye precursor) and a color developer (acidic or basic substance), a combination of a diazonium salt and a coupler compound, a combination of a polyvalent metal compound and a ligand, and the like are exemplified. Specifically, the coloring agent is crystal violet lactone, malachite green lactone,
Benzoylleucomethylene blue, 3-diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-chlorofluoran, phenolphthalein, fluorescein, 4,5,6,7- Activated clay, 4,4'-isopropylidene diphenol, 4,4'-
Cyclohexylidene diphenol, 4-phenylphenol-formalin condensate, pt-butylphenol,
Benzyl p-hydroxybenzoate, butyl p-hydroxybenzoate, gallic acid, salicylic acid, salicylic anilide, 3,5-di-t-butylsalicylic acid, and metals modified with polyvalent metals such as zinc, aluminum and magnesium Modified phenolic compounds, metal salts of aromatic salicylic acids, 1,2-diphenylguanidine, 1,2,3-tricyclohexylguanidine, phenylthiourea, tribenzylamine, 2-benzylimidazole, 2-phenyl-2-imidazoline, 2-aminobenzothiazole and the like.

The diazonium salts include 4-N, N-dimethylaminobenzenediazonium chloride, 4-morpholinobenzenediazonium chloride, 4-tolylmercapto-2,5-
Diethoxybenzenediazonium chloride and the like include coupler compounds such as pyrocatechol, resorcinic acid, naphthol, 2-hydroxy-3-naphthoic acid morpholinopropylamide, acetoacetic anilide, and 1-phenyl-3-.
Carboxypyrazolone, cyanoacetanilide and the like.

Polyvalent metal compounds include ammonium metavanadate, ferric alum, sodium orthovanadate, ferric naphthenate, iron stearate, silver behenate, etc., and ligands such as tannic acid, protocatechuic acid, Dodecyl gallate, N-
Lauroyl-DL-glutamic acid, tetrachlorocatechol, 2,3-dihydroxynaphthalene and the like. These are used by dissolving or dispersing them in a fine powder or a photopolymerizable compound.

The thing encapsulated in the microcapsules used in the present invention include, in addition to the photopolymerizable compound and the color image forming agent, a photopolymerization initiator such as benzoin alkyl ether, benzophenone, Michler's ketone, thioxanthone, and acetophenone, For example, sensitizers such as amines, anthraquinones and fluorenes; stabilizers and modifiers such as thermal polymerization inhibitors; and silver halides, organic silver salts and resorcinols, and 5-pyrazolones. And a sensitivity improving agent in combination with a reducing agent such as substituted naphthols and hydrazines.

The microcapsules used in the present invention can be manufactured by a method known in the art. For example, U.S. Pat.
Separation method from aqueous solution as shown in JP-A No. 2800458, JP-A No. 2800458, JP-B-38-19574, 42-446, 42-446
Interfacial polymerization method as shown in No. 771, etc., JP-B-36-9168
JP-A-51-9079, in-situ method by polymerization of monomers, British Patent No. 952807, melt separation cooling method shown in US Pat. No. 965074, U.S. Pat. No. 930422, etc., but not limited thereto. Examples of wall film forming agents include gelatin, gum arabic, starch, sodium alginate, ethyl cellulose, carboxyethyl cellulose, polyvinyl alcohol, polyethylene,
Polyamide, polyester, polyurethane, polyethyleneimine and the like are used, and a material that sufficiently transmits light for exposure is more preferable.

The size of the microcapsules used in the present invention is preferably 100 μm or less, more preferably 30 μm or less, in view of the effect on image quality and handling before use. Since the wall thickness and particle size of the microcapsules affect the breaking pressure, it is preferable to determine the size of the microcapsules in consideration of the wall thickness.

In the present invention, an organic solvent can be used. By using an organic solvent, the solubility of the compound encapsulated in the microcapsules is improved, and it can be present at a high concentration, and the breaking strength of the microcapsules is adjusted.
In some cases, the transfer efficiency of inclusions can be improved. However, when used in a large amount, the degree of curing of the microcapsules is adversely affected.
~ 300% is preferred. Specific examples of the organic solvent include alkyl naphthalenes, alkyl biphenyls, diaryl alkylenes, lower alkyl acetates, phthalic acid alkyl esters, phosphate esters, fatty acid esters, alcohols, and the like.

When the light-reflective compound is held on a support, a water-soluble polymer or latex is generally used alone or in combination. Examples include gelatin, casein, carboxymethylcellulose, hydroxymethylcellulose, oxidized starch, esterified starch, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, vinyl acetate-acrylate copolymer, acrylonitrile-butadiene copolymer, and the like. These water-soluble polymers and latexes are also used when the photosensitive layer is coated on a support or a layer containing a light-reflective compound.

As a light source for curing the microcapsules used in the present invention, sunlight, a xenon lamp, a fluorescent lamp, a halogen lamp, a low- and high-pressure mercury lamp, a laser beam, a light-emitting diode and the like are used.

One or more wavelengths, usually 3
Irradiate light of wavelength. The wavelength can be arbitrarily selected in a photosensitive region where the photopolymerizable compound is cured, and the light source can be selected accordingly.

As the support used in the image forming material of the present invention, a transparent, translucent or opaque support can be arbitrarily selected. For example,
Paper, various nonwoven fabrics, synthetic paper, metal foil and polyethylene terephthalate film, polystyrene film, acetyl cellulose film, polyvinyl acetal film,
A plastic film such as a polyethylene film or a composite sheet obtained by combining them, for example, paper laminated with a polymer such as polyethylene can also be used. These supports are also used for the image receiving sheet.

Also, if necessary for the image forming material and the image receiving sheet,
Cellulose powder, starch particles, plastic particles, calcium carbonate, zinc oxide, titanium oxide, talc, urea
Inorganic and organic fine powders such as formalin resin, fluorescent whitening agents,
Antifoggants, surfactants and the like may be added.

(Examples) Hereinafter, the image forming material of the present invention will be specifically described with reference to examples.

Example 1 (1) Production of microcapsules containing dye precursor 100% aqueous solution of ethylene-maleic anhydride copolymer 100
g, urea 10 g, resorcin 1 g and water 200 g were mixed and stirred, and an aqueous sodium hydroxide solution was added so that the aqueous solution had a pH of 3.5.

Separately, trimethylolpropane triacrylate 165.
3- (N-furylmethyl-N-ethyl) amino-6 was added to 6 g.
14.4 g of -methyl-7-anilinofluoran was dissolved by heating, and 3.3 g of 2,4-diethylthioxanthone and 1.6 g of ethyl p-dimethylaminobenzoate were added. In addition, it was emulsified and dispersed.

An oil-in-water emulsion having oil droplets of 4 to 8 microns was obtained.

Next, 2.5 g of a 37% aqueous formaldehyde solution was added under light shielding, the solution temperature was kept at 55 ° C., and stirring was continued for 4 hours, and then cooled to room temperature to complete microencapsulation.

(2) magnesium oxide 10g to create a 2% aqueous solution of polyvinyl alcohol 90g of the photosensitive sheet is added, the coating dried sufficiently stirred after, basis weight 60 g / m dry ² of synthetic paper weight 4g / m ² and composed as Meyer bar Then, a primer paper was obtained. Further, on the magnesium oxide undercoated paper, 10 g of the dye precursor-containing microcapsules prepared in (1), 6 g of wheat starch, 3.6 g of 50% SBR latex,
40 g of water was added, and the coating solution sufficiently stirred was applied and dried using a Meyer bar to obtain a photosensitive sheet.

(3) Preparation of Image Receiving Sheet 20 g of Shilton was added to 75 g of a 4% aqueous solution of polyvinyl alcohol, and after sufficient stirring, it was applied to a base paper having a basis weight of 60 g / m ² using a Meyer bar and dried to obtain an image receiving sheet.

Example 2 A photosensitive sheet was obtained in the same manner as in Example 1, except that magnesium carbonate was used instead of magnesium oxide in the preparation of the photosensitive sheet of Example 1.

Comparative Example 1 A photosensitive sheet was obtained in the same manner as in Example 1 except that the undercoat of magnesium oxide was omitted in the preparation of the photosensitive sheet of Example 1.

Image formation and evaluation Xenon light was used as a light source on the microcapsule-coated surface of the photosensitive sheet obtained in Examples 1 and 2 and Comparative Example 1, light having a wavelength of 380 nm was selected through a diffraction grating, and irradiated through an image-like original. did. The exposed photosensitive sheets were overlapped so that the coated surfaces of the image receiving sheets faced each other, and were pressed using a pressure roll. A clear black image was formed imagewise on the portion of the image receiving sheet facing the unexposed portion. The density of the exposed portion changes depending on the amount of light irradiation. The irradiation amount of the portion where the density was 0.1 or less was examined for each photosensitive sheet. The irradiation amount is shown in Table 1 as an energy amount.

The smaller the value of the irradiation energy, the harder the microcapsules are hardened by a small amount of light, indicating higher sensitivity.

As is clear from the examples in Table 1, the irradiation energy is reduced to 1350 and 1120 erg / cm ² and 1500 erg / cm ² or less by containing magnesium oxide or magnesium carbonate which is a specific light reflecting compound as a main component. Sensitivity can be improved. The sensitivity can be similarly improved by adding a specific light-reflective compound such as alumina, barium sulfate, zircon oxide or a condensable triazine compound to the layer as a main component. On the other hand, if nothing is contained in the layer, the irradiation energy will be 1730 erg / cm ² and the sensitivity will not be improved. When the layer contains titanium oxide, which is a light-absorbing compound, the irradiation energy becomes 2000 erg / cm ² or more, the irradiation energy increases as compared with the case where no layer is contained, and the sensitivity deteriorates.

(Effect of the Invention) The image-forming material of the present invention contains a specific light-reflective compound in a support, or a photosensitive layer containing microcapsules mainly containing a photopolymerizable compound and a color image-forming agent,
The sensitivity could be improved by providing a layer containing a specific light-reflective compound between the supports.

Continuation of the front page (56) References JP-A-61-130945 (JP, A) JP-A-61-24495 (JP, A) JP-A-62-3246 (JP, A) JP-A-61-275742 (JP, A) JP-A-63-206737 (JP, A) JP-A-1-17043 (JP, A) JP-B-49-33783 (JP, B1)

Claims (1)

(57) [Claims] An image forming material comprising a support and a photosensitive layer containing at least a microcapsule mainly containing a photopolymerizable compound and an image forming agent coated thereon. An image-forming material comprising a layer containing, as a main component, a light-reflective compound comprising at least one of magnesium, magnesium carbonate, barium sulfate, zircon oxide and a condensable triazine compound.