JPS597089A - Recording material - Google Patents

Abstract

PURPOSE:To obtain a heat-sensitive recording material having excellent recording sensitivity and free of coloration in recording layer by adding zinc oxide and a clay mineral subjected to baking treatment to the recording layer. CONSTITUTION:10-400pts.wt. one or more of zinc compounds to form zinc oxide when heated and zinc oxide and 100pts.wt. one or more of clay minerals (e.g., kaolinite, etc.) subjected to a baking treatment at 800-1,100 deg.C (or at 500 deg.C or higher) are ground into fine powder, and 3-90wt% the fine powder, together with a coloring agent, a colorant, etc., is dispersed in a liquid to obtain a heat- sensitive coating liquid. The coating liquid is coated on a supporter and dried to obtain an objective recording material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal recording medium, and particularly to a thermal recording medium having excellent recording sensitivity as a thermal recording medium for infrared laser.

Conventionally, heat-sensitive recording materials are well known, which utilize a coloring reaction between a coloring agent and a coloring agent that develops color when they come into contact with the coloring agent, and bring both substances into contact with each other using heat to obtain a colored image. There is.

In addition, as a recording method for such a heat-sensitive recording medium, a method in which recording is performed by closely scanning a recording layer with a "yt" (thermal head) having a heating element is generally used. However, such a method This tends to cause abrasion of the head (1), adhesion of debris to the head surface, and so-called sticking trouble in which the head and recording layer stick together.Furthermore, the recording speed is dependent on the heat dissipation time of the thermal head. High-speed recording is difficult because of the dependence on heat, and there is also a limit to the resolution of colored images due to thermal diffusion.

Therefore, instead of such a thermal head contact scanning method, various techniques have been proposed for non-contact recording by scanning with high energy density light such as a laser beam.

Thermal recording is performed by scanning such a laser beam. However, in the method of exchanging heat energy with the light/heat exchange material on the device side and then supplying it to the recording medium, thermal energy diffuses and accumulates on the light/heat exchange material, making it impractical. On the other hand, in the method of directly absorbing laser light into the recording medium, general heat-sensitive recording materials hardly absorb visible and near-infrared light (2) with a wavelength of 400 to 2000 nm. For example, a light-absorbing substance such as a colored dye, a carbon blank, or a metal powder may be incorporated into the recording layer, or a layer may be provided between the recording layer and the support, or a vapor-deposited metal film that absorbs laser light may be formed on the surface of the recording layer. However, these methods are not practical because the recording layer is colored and the manufacturing process is complicated.

Focusing on the fact that general heat-sensitive recording materials absorb infrared light, a method using an infrared laser has been proposed, but this method has not yet achieved practical recording sensitivity.

In view of the current situation, the present inventors have developed a method that does not have a colored recording layer.
Furthermore, in order to obtain a heat-sensitive recording material for laser use having practical recording sensitivity, the present invention was completed as a result of intensive research into a recording material that uses infrared radiation as a recording light source.

The present invention provides at least one compound selected from zinc oxide and zinc compounds that generate zinc oxide upon heating, and a viscosity-1
- A heat-sensitive recording material characterized by containing a fired product obtained by firing at least one mineral at a temperature of 500° C. or higher (3).

In the present invention, 1. The important feature is that a specific fired product is used as shown in L. Here, the compound that is fired with clay minerals to obtain the fired product is zinc oxide, and the zinc oxide is fired by heating (firing). At least one type of compound is used. Various compounds are known for chemically converting zinc oxide by heating, but zinc hydroxide and zinc carbonate are more preferably used because of ease of firing treatment and easy availability of materials.

Various clay minerals are known to be fired together with such zinc compounds, and specific examples include pyrophyllite, talc, minnesotaite, montmorillonite, nontronite, zabonite, vermiculite, sericite, illite, heptaradonite, amesite, pennin,
lyhydrite, thuringai 1-, abrosiderite, kaolinite, dikite, nacrite, metahalosite, hallosite, serpentine, sepiolite, parigo (
4) Ruskite, attapulgite, etc. are exemplified.

Among these clay minerals, talc, montmorillonite, sericite, kaolinite and the like are particularly preferably used because they not only provide the desired effects of the present invention but also have particularly excellent whiteness.

The firing treatment conditions for zinc compounds and clay minerals are determined as appropriate depending on the materials used, etc.
Generally, 1 liter of zinc compound is added to 100 parts by weight of clay mineral.
0 to 400 parts by weight of the mixture is treated by calcining it in the presence of air at a temperature of 500 DEG C. or higher, preferably 800 DEG C. to 1100 DEG C., for 1 to 3 hours.

Since the calcined product of zinc compounds and clay minerals obtained by this method is generally used in the form of powder, it is pulverized by a suitable pulverizer such as a roll pulverizer or an impact pulverizer, and further processed by a sand grinder or the like if necessary. A fine pulverization process is performed.The smaller the particle size of the powder, the better the sensitivity improvement effect, so it is generally desirable to use the powder by pulverizing it to 1077 or less, more preferably 5μ or less.These fired products The amount to be used (5) cannot be determined because it varies depending on the intensity of the infrared laser beam used, etc., but it is generally used in an amount of 3% by weight or more based on the total solid content of the recording layer.

However, if too large an amount is used, there is a risk of a decrease in color density, so the amount is preferably adjusted within the range of 3 to 90% by weight, most preferably 10 to 80% by weight.

The heat-sensitive recording material of the present invention is generally produced by a method in which a support is coated with a heat-sensitive coating liquid in which one or more color formers, color formers, and fine particles of the specific fired product are dispersed. It can also be produced by a method in which two or three types of heat-sensitive coating liquids in which a coloring agent and a fired product are separately dispersed are applied onto a support in layers. Furthermore, it can also be produced by impregnating a support with part or all of the coloring agent, the coloring agent, and the fired product, or by rolling it into the support.

The combination of coloring agent and coloring agent used in the present invention is not particularly limited, and any combination (6) that causes a coloring reaction when the two come into contact with each other due to heat can be used. Examples include combinations of colorless or light-colored basic dyes and inorganic or organic acidic substances, and combinations of higher fatty acid metal salts such as ferric stearate and phenols such as gallic acid.

Furthermore, it is also possible to apply the present invention to various heat-sensitive recording materials that obtain a developed color image (recorded image) by heat, such as a heat-sensitive recording material that combines a diazonium compound, a coupler, and a basic substance. It also includes recording media.

However, when the specific fired product used in the present invention is applied to a combination of a basic dye and an acidic substance among various combinations, it not only has the effect of improving recording sensitivity but also eliminates the need for a recording layer before use. Such a combination is preferably used because it exhibits excellent properties in improving the so-called fogging phenomenon that causes color development.

Various types of colorless to light-colored basic dyes are known, and examples include the following.

3.3-bis(p-dimethylaminophenyl)-(7) 6-dimethylaminophthalito, 3.3-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl)-3- (1,2-dimethylindole-
3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(2-methylindol-3-yl)phthalide, 3,34:'s(1,2-dimethylindole-3
-yl)-5-dimedylaminophthalide, 3.3-bis(1゜2-dimethylindol-3-yl)-6-dimethylaminophthalide, 3.3-bis(9-ethylcarbazol-3 -yl)-6-dimethylaminophthalide, 3
．． 3-bis(2-phenylindol-3-yl)-6
-dimethylaminophthalide, a-p-dimethylaminophenyl-3-(1-methylpyrrol-3-yl)-6-
triallylmethane dyes such as dimethylaminophthalide,
4.4'-bis-dimethylaminohenzhydrylhenzyl ether, N-halophenyl-leucoolamine, N
-2,4,5-) Diphenylmethane dyes such as dichlorophenyl leuco auramine, hendiyl (8) Thiazine dyes such as leucomethylene blue and p-nitrobenzoyl leucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3 -Ethyl-spiro-dinaphthopyran, 3-phenyl-spiro-dinaphthopyran, 3-benzyl-spiro-dinaphthopyran, 3-methyl-naphthopyran
Spiro dyes such as (6'-methoxyhenzo)spiropyran and 3-propyl-spiro-dibenzopyran; lactam dyes such as rhodamine-13-anilinolactam, rhodamine(p-nitroanilino)lactam, and rhodamine(0-chloroanilino)lactam Dye, 3-dimethylamino-
7-methoxyfluoran, 3-diethylamino-6-methoxyfluoran, 3-diethylamino-7-methoxyfluoran, 3-diethylamine-7-chlorofluoran, 3-diethylamine-6-methyl-7-chlorofluoran, 3-diethylamine-6,7-dimethylfluorane, 3-(N-ethyl-p-toluidino)-7-methylfluorane, 3-diethylamino-7-N-acetyl-N-methylaminofluorane, 3-( 9) Diethylamino-7-N-methylaminofluorane, 3
-diethylamino-7-dibenzylaminofluorane,
3-diethylamino-7-N-methyl-N-benzylaminofluorane, 3-diethylamino-7-N-chloroethyl-N-methylaminofluorane, 3-diethylamino-7-N-diethylaminofluorane, 3-(N −
Ethyl-p-)luidino)-6-methyl-7-phenylaminofluorane, 3-(N-ethyl-p-toluidino)-6-methyl-7-(p-)luidino)fluorane,
3-diethylamino-6-methyl-7-phenylaminofluorane, 3-diethylamine-7-(2-carbomethoxy-phenylamino)fluorane, 3-(N-cyclohexyl-N-methylamine)-6-methyl-7 -phenylaminofluorane, 3-pyrrolidino-6-methyl-7-phenylaminofluorane, 3-piperidino-6
-Methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl-7-xylidinofluorane, 3
-diethylamine-7-(0-ri(10) lorophenylamino)fluoran, 3-dibutylamino-7-(0-chlorophenylamino)fluoran, 3-
Fluoran dyes such as pyrrolidino-6-methyl-7-p-butylphenylaminofluoran, etc.

Various types of inorganic or organic acidic substances that develop color upon contact with basic colorless dyes are also known, and examples thereof include the following.

Inorganic acidic substances such as activated clay, acid clay, acpulgite, hentonite, colloidal silica, aluminum silicate, 4-tert-butylphenol, 4-hydroxydiphenoxide, α-naphthol, β-naphthol, 4-hydroxyacetophenol, 4 -tert-
Octylcatechol, 2,2'-dihydroxydiphenol, 2,2'-methylenebis(4-medyl-6-t)
ert-isobutylphenol), 4.4'~isopropylidenebis(2-also ert-butylphenol),
4. 4'-5ec-butylidene diphenol, 4-
Phenylphenol, 4.4'-isopropylidenediphenol, 2° (11) 2'-methylenehis (4-chlorophenol), hydroquinone, 4.4'-cyclohexylidenediphenol, novolac type phenolic resin, phenol polymer Phenolic compounds such as benzoic acid, p-tert-butylbenzoic acid, trichlorobenzoic acid, terephthalic acid, 3-
sec-butyl-4-hydroxybenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid, 3,5-dimethyl-4-hydroxybenzoic acid, salicylic acid, 3-isoprobylsalicylic acid, 3-tert-butylsalicylic acid,
3-henzylsalicylic acid, 3-(α-methylhensyl)
salicylic acid, 3-chloro-5-α-methylhensyl)
Aromatic carboxylic acids such as salicylic acid, 3,5-di-tert-butylsalicylic acid, 3-phenyl-5-(α,α-dimedylhenzyl)salicylic acid, 3,5-di-α-methylhenzylsalicylic acid, and these phenolic acids compounds, aromatic carboxylic acids and e.g. zinc, magnesium,
aluminum, calcium, titanium, manganese, tin,
ta-acidic substances such as salts with polyvalent metals such as nickel (
12) etc.

In the heat-sensitive recording material of the present invention, the ratio of the coloring agent and coloring agent used in the recording layer is appropriately selected depending on the type of coloring agent and coloring agent used, and is not particularly limited. For example, when using a basic colorless dye and an acidic substance,
- Generally 1 to 5 parts by weight per 1'111 parts by weight of basic colorless dye
0 parts, p parts or 4 to 7 parts of acidic material are used.

To prepare a coating solution containing these substances, generally, water is used as a dispersion medium, and the coloring agent and the coloring agent are dispersed together or separately using a ball mill, an attritor, a sand grinder, etc., or a grinder. However, the powder of the specific fired product according to the present invention may be dispersed simultaneously in these dispersion steps, or may be added to the coating solution after dispersion. .

In addition, such coating liquids usually contain starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein,
Gum arabic, polyvinyl alcohol, methylene,
Maleic anhydride copolymer salt, (13) styrene/°1 acrylic acid coelectrolyte salt, styrene/butadiene copolymer emulsion, etc. with a total solid content of 2 to 40%.
% by weight, preferably 5 to 25% by weight. Furthermore, various auxiliary agents can be added to the coating liquid. For example, dispersants such as dioctyl sulfonitrisuccinate, sodium dotecilhenzenesulsomenate, sodium lauryl alcohol sulfate ester, fatty acid metal salts, ultraviolet absorbers such as hensifenones and triazoles, and other disinfectants. Examples include foaming agents, fluorescent dyes, and colored dyes.

Furthermore, inorganic pigments such as kaolin, clay, talc, calcium carbonate, calcined clay, titanium oxide, diatomaceous earth, fine particulate anhydrous silica, and activated clay may be added to further whiten the heat-sensitive recording layer.

In addition, stearic acid amide, stearic acid methylene bisamide, oleic acid amide, palmitic acid amide,
Fatty acid amides such as matcha oleic acid amide and coconut fatty acid amide, stearic acid, polyethylene, carnauba wax, paraffin wax, and waxes such as dispersions or emulsions such as calcium thearate and ester wax may be added as sensitizers. You can also do it.

In the heat-sensitive recording material of the present invention, the method of forming the recording layer is not particularly limited as described above, and can be formed according to conventionally well-known and commonly used techniques. For example, in a method of applying a heat-sensitive coating liquid to a support, an appropriate coating device such as an air knife coater or a blade coater is used. Further, the amount of the coating liquid to be applied is not particularly limited, and is generally adjusted within the range of 2 to 12 g/rl, preferably 3 to 10 g/m in terms of dry weight. In addition,
The support is not particularly limited either, and paper, synthetic fiber paper, synthetic resin film, etc. can be used as appropriate, but paper is generally preferably used.

(Thus, the heat-sensitive recording material obtained by the present invention has no unnecessary coloring of the recording layer, and has extremely excellent recording sensitivity as a recording material that uses an infrared laser as a recording light source, and is superior to conventional contact recording materials. It also enables high-speed recording that cannot be achieved with conventional recording methods (15). The effect is remarkable, and the heat-sensitive recording material of the present invention exhibits extremely excellent characteristics as a heat-sensitive recording material for carbon dioxide laser.

EXAMPLES Examples and comparative examples are listed below in order to make the effects of the present invention even clearer, but the present invention is not limited thereto. Note that % in the examples does not represent weight %.

Example 1 A dispersion liquid (A) in which water was added to 25 g of 3-his(p-dimethylaminophenyl)-6-dimethylaminophthalide and 5 g of a 10% polyvinyl alcohol aqueous solution to make the solid content concentration 25%, and 4. 100g of 4'-isopropylidene diphenol, 10% borihinyl alcohol water? g
? & sg and water to make a 25% concentration dispersion (
B) were each processed in a magnetic ball mill for 8 hours.

A fired product obtained by previously firing 125 g of kaolinite and 125 (16) g of zinc oxide at 800°C for 3 hours, 15 g of a 10% polyvinyl alcohol aqueous solution, and 1000 g of water.
The mixed dispersion (C) was processed with a sand grinder so that the average particle size was 4 μm.

After treatment (Δ), (B), (C) three dispersions were mixed,
Furthermore, 100 g of styrene-butadiene-acrylic acid ester copolymer Latinx (solid content concentration 50%) was added to obtain a coating liquid for heat-sensitive recording.

The resulting coating liquid was applied to a 49 g/% monochrome layer at a dry coating weight of 7 g/m and dried to obtain a blue-colored thermosensitive recording paper.

Example 2 Instead of the kaolinite used in Example 1 (dispersion liquidization),
A thermosensitive recording paper was obtained in the same manner as in Example 1, except that a fired product obtained by firing talc at 1200° C. for 3 hours was used.

Comparative Example 1 Heat-sensitive recording paper was prepared in the same manner as in Example 1 except that kaolinite before firing and zinc oxide (17) were used instead of the specific fired product used in dispersion (C) of Example 1. I got it.

Comparative Example 2 A thermosensitive recording paper was obtained in the same manner as in Example 2, except that talc and zinc oxide before firing were used instead of the specific fired product used in Example 2.

Example 3 3,3-bis(p-
1-(N-edyl-p-)luidino)-6 instead of dimethylaminophenyl)-6-dimethylaminophenyl
A black coloring thermosensitive recording paper was obtained in the same manner as in Example 1 except that -Medyl-7-phenylaminofluorane was used.

Example 4 The same procedure as in Example 3 was used except that the specific fired product used in dispersion (C) was a fired product obtained in the same manner except that zinc oxide was replaced with zinc carbonate. A thermosensitive recording paper was obtained.

Example 5 A product obtained in the same manner as in Example 3 except that 65 g of zinc hydroxide and 60 g of zinc oxide were used as the specific baked product (18) used in dispersion (C) in place of 125 g of zinc oxide. A thermosensitive recording paper was obtained in the same manner as in Example 3 except that the fired product was used.

Evaluation test examples 1 to 5 and comparative example 1. Using the thermal paper obtained in step 2, a carbon dioxide laser (output IW, center oscillation wavelength 10
．． 6μ, beam diameter 100μ), the linear density IQline
/+n, and the color density was measured with a Macbeth density needle. From the relationship between the recording speed and the color density, the recording energy density required to obtain a color density of 0 was determined and is shown in Table 1.

The Macbeth density needle filter was a red filter in Example 1.2 and Comparative Example 1.2, and a red filter in Examples 3 and 4.
5 was measured using a yellow filter.

As is clear from Table 1, the thermal recording paper obtained in the present invention had excellent recording sensitivity as a thermal recording medium for laser use.

Patent applicant: Kanzaki Paper Co., Ltd. 4F

Claims (1)

[Claims] (1,) Contains a fired product obtained by firing at least one compound selected from zinc oxide, a zinc compound that produces zinc oxide upon heating, and at least one clay mineral at a temperature of 500°C or higher. A heat-sensitive recording material characterized by: