JPS60225796A - Laser recording material - Google Patents

Abstract

PURPOSE:To prevent thermal fogging from occurring during preservation, facilitate washing of non-image parts at the time of development and contrive formation of sharp images, by providing a recording layer comprising a particulate thermoplastic resin and an photo-thermal converting substance as main constituents on a base. CONSTITUTION:The thermoplastic resin used in the recording layer is an emulsion-type polymer or copolymer having a minimum film-forming temperature of 80-150 deg.C, e.g., a polymer or copolymer of acrylic acid, styrene or vinyl acetate. The photo-thermal converting substance is a substance capable of absorbing laser light and converting it into heat, e.g., an inorganic or organic pigment such as carbon black, a phthalocyanine pigment, iron and graphite or an IR absorber such as a cyanine coloring matter and an anthraquinone compound. To produce the recording material, the thermoplastic resin is mixed with the photo-thermal converting substance and optionally with a water-soluble binder, the resultant mixture is uniformly dispersed by ultrasonic waves, an attritor or the like, the dispersed liquid is applied to a base so as to provide a dried thickness of 1-10mum, and is dried at a temperature not higher than the minimum film-forming temperature.

Description

TECHNICAL FIELD The present invention relates to a laser recording material in which a water-developable latent image is formed by laser light.

Prior Art Conventionally, paper has been used as a heat-sensitive recording material that forms a latent image using the properties of photothermal converting substances such as iron powder and carzen black that absorb light and convert it into heat, and then develops this with water. The photothermal converting substance and a thermocoagulable protein such as albumin are placed on a support such as a film (Japanese Patent Publication No. 10870/1987).
, ionomer resin particles and water-soluble resins (Japanese Patent Application Laid-open No. 1983-
148590 (Japanese Unexamined Patent Publication No. 148590), those provided with a heat-sensitive layer mainly composed of a resin such as phenol resin particles and a water-soluble resin (Japanese Unexamined Patent Publication No. 148589/1989) are known. In this type of heat-sensitive recording material, the surface of the heat-sensitive layer is imagewise exposed to infrared rays to thermally coagulate, melt, or thermally crosslink the exposed portion of the protein, ionomer resin, or phenol resin, respectively, thereby making this portion poorly soluble or insolubilized in water. An image is then formed by dissolving and removing the original water-soluble unexposed areas in a developer (water).

Therefore, this type of heat-sensitive recording material can be used for laser recording, but heat buildup is likely to occur during storage, and as a result, during development, unexposed areas (non-image areas) are difficult to dissolve, and edges are easily cut off. It was difficult to get good sharp images.

Object The object of the present invention is to provide a laser recording material that can prevent heat build-up during storage, facilitate washing out non-image areas during development, and form sharp images with good edges. That's true.

Structure The laser recording material of the present invention has a recording layer on a support whose main components are thermoplastic resin particles having a minimum film forming temperature of 80 to 150°C and a photothermal converting substance that absorbs laser light and converts it into heat. It was established.

The thermoplastic resin used in the recording layer of this T3 light may have a minimum film forming temperature in the range of 80 to 150°C. These thermoplastic resins are all emulsion-type polymers or polymer copolymers, such as acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, styrene, α-methylstyrene, vinyl acetate, and chloride. vinyl,
Examples include polymers or copolymers such as vinylidene chloride, ethylene, soloterene, and inzotyrene; among these, methacrylic acid and its esters, styrene, and α-methylstyrene are monomers with relatively high minimum film-forming temperatures; The other monomers are monomers having a relatively low minimum film forming temperature. Therefore, when used as a copolymer, these two
Various types of monomers are used in appropriate combinations.

Note that if the minimum film forming temperature is less than 80°C, there will be a large amount of fog during storage, and the solubility of non-image areas will decrease, resulting in poor development, and if it exceeds 150°C, a high-power laser will be required. , becomes impractical.

As the photothermal converting substance used in the recording layer, any substance that can absorb laser light and convert it into heat can be used.
For example, inorganic or organic pigments such as carin black, carin graphite, phthalocyanine pigments, iron, graphite, iron oxide, silver oxide, chromium oxide, iron sulfide, chromium sulfide, etc., and even those with maximum absorption wavelength in the near-infrared light region. So-called infrared absorbers, such as quanine dyes, JP-A-58-16888
Diamine-based metal complexes and dithiol-based metal complexes described in the No.
Examples include mercaptophenol metal complexes, arylaluminum salts, and anthraquinone compounds described in JP-A-59-26293.

Note that the ratio of the thermoplastic resin to the photothermal converting substance in the recording layer is suitably about 1:0.1 to 5 (by weight).

In addition, a water-soluble binder may be added to the recording layer up to about 90% of the layer weight, if necessary. Examples of this kind of binder include gelatin, starch, PVA, etc.
Examples include ribinylpyrrolidone, methylcellulose, hydroxyethylcellulose, vinyl alcohol-maleic acid copolymer, and the like.

Supports used in the present invention include paper, plastic films (e.g. polyethylene, IJ propylene,
Paper laminated with polystyrene (film such as polystyrene), synthetic paper, metal plate (e.g. aluminum, zinc, iron, copper, etc. plate), plastic film (e.g. cellulose acetate, cellulose nitrate, polyethylene terephthalate); IIJ
(films of styrene, polypropylene, polycarbonate, etc.), plastic plates or plastic films on which metals such as those described above are vapor-deposited, plated, or laminated (specific examples of plastics are as described above).

To make the recording material of the present invention, for example, the above-mentioned thermoplastic resin,
Mix a photothermal converting substance and a water-soluble inder if necessary, and disperse it uniformly (by ultrasonic dispersion, attritor dispersion, etc.), and this dispersion has a thickness of about 1 to 10 μm after drying. It is sufficient to coat the film onto a support and dry it at a temperature below the minimum film forming temperature.

The principle of image formation using the recording material of the present invention is completely the same as the conventional one. That is, by image-wise exposing the recording material to a laser beam from the front or back surface, the photothermal converting substance in the exposed area is heated,
This heat melts the thermoplastic resin particles in that area, creating a difference in solubility in the developer (water). The laser light source used here is He
-Ne laser, semiconductor laser, YAG laser f-1
There are charcoal mlJ lasers, argon lasers, etc. Particularly preferred is one with an output of about 0.1 to 3 W.

Effects As described above, since the laser recording material of the present invention uses a thermoplastic resin with a minimum film forming temperature of 80 to 150°C, there is no fogging during storage, and this makes it easy to develop. , and it is possible to form a sharp image with good edges.

Examples of the present invention are shown below. Note that parts and % are combined weight parts and weight %, respectively.

Example 1 Car-in black 2 parts 49% emulsion of folystyrene (jl low film forming temperature M
FT=110℃) (Polysol C-10 manufactured by Showa Kobunshi Co., Ltd.
) 4 parts 10% aqueous solution of PVA (degree of saponification 89%, average degree of polymerization 500) 4 parts water 2 parts were mixed, and after ultrasonic dispersion, this dispersion was spread on a 100μ thick polyester film with wire holes. - and dried at 80° C. to prepare a recording material having a recording layer of 3 μm thickness.

Example 2 A 40% emulsion of styrene acrylate copolymer (MFT=100°C) was used instead of Polysol C-10.
) (Movinyl 970 manufactured by Hoechst Gosei Co., Ltd.) was used, but a recording material was prepared in the same manner as in Example 1.

Example 3 Copper phthalocyanine 2 parts 7]e! J 45% emulsion of vinyl mide (MF
Recording was carried out in the same manner as in Example 1 using 3 parts of a 10% aqueous solution of methyl cellulose. Created the material.

Comparative Example 1 39% of ionomer resin in place of Polysol C-10
Emulsicon (MFT = 45°C) (Koromoran Latex L-6000 manufactured by Asahi Dow Co., Ltd.) was used, and the drying temperature was set to 3.
A recording material was prepared in the same manner as in Example 1 except that the temperature was 0°C.

Next, the recording layer side of the above-mentioned recording material was imagewise exposed to the laser beam shown in the table below, focused to a beam diameter of 20 μm, at the scanning speed shown below, and then immersed in water.

The non-exposed areas were dissolved and removed by rubbing the recording layer with absorbent cotton. In addition, after leaving each recording material in a constant temperature bath at 40°C for one week,
A similar operation was performed. The results are shown in the table below.

(Hereinafter referred to as margins) As can be seen from this table, the products of the present invention had no decrease in scanning speed, no thick lines, had excellent storage stability, and produced sharp images.

Patent applicant Rico Co., Ltd.

Claims (1)

[Claims] 1. A laser recording material comprising a support and a recording layer whose main components are thermoplastic resin particles with a minimum film formation temperature of 80 to 150°C and a photothermal converting substance that absorbs laser light and converts it into heat. .