JPH0464482A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material generating no stickiness and refuse adhesion trouble and excellent in head matching properties by adding hydrous halloysite to a thermal color forming layer based on a leuco dye and a developer. CONSTITUTION:In a thermal recording material utilizing the color forming reaction of a leuco dye and a developer, hydrous halloysite is compounded to prepare the thermal recording material. The chemical composition of hydrous halloysite is same to that of kaolinite but most characterized by that the particle shape thereof is spherical and the thermal recording material using hydrous halloysite as one of various components is reduced in the adhesion of refuse to a thermal head. Further, hydrous halloysite is contained in an amount of 10-90% by wt. of a thermal color forming layer and 10-90% by wt. of a protective layer or 10-90% by wt. of both layers but pref. contained in an amount of 30-50% by wt. of the thermal color forming layer and 30-50% by wt. of the protective layer or 30-50% by wt. of both layers to still more develop effect.

Description

[Detailed Description of the Invention] [Prior Art] Thermosensitive recording materials generally have a thermochromic layer containing a thermochromic composition as a main component on a support such as paper, synthetic paper, or plastic film. A colored image can be obtained by heating with a thermal pen, laser light, etc. Compared to other recording materials, this type of recording material does not require complicated processing such as development and fixing, and records can be obtained in a short time using relatively simple equipment, and it generates less noise and pollutes the environment. Due to its advantages such as low cost and low cost, it is used not only for copying books and documents, but also as a recording material in a wide range of applications such as electronic computers, facsimile machines, ticket vending machines, labels, and recorders.

Thermal color-forming compositions used in such isothermal recording materials generally consist of a color former and a color developer that causes the color former to develop color when heated.As the color former, for example, lactone, lactam or spiropyran ring is used. Colorless or light-colored leuco dyes are used, and various acidic substances such as organic acids and phenolic substances are used as color developers. Recording materials that combine this color forming agent and color developer have the advantage that the resulting image has a particularly clear color tone, has a high background whiteness, and has excellent weather resistance, and is widely used. has been done.

In recent years, as heat-sensitive recording materials have replaced other conventional recording methods and demand for them has increased, there has also been an increasing demand for improving the quality of heat-sensitive recording materials used in these heat-sensitive recording methods. There is a demand for heat-sensitive recording materials with excellent head matching properties that are trouble-free and do not affect head life.There are many methods known to use organic or inorganic fillers to improve head matching properties. It is being

For example, Japanese Patent Publication No. 57-20918 describes a method using water-insoluble urea-formalin resin fine powder;
No. 98, Japanese Patent Publication No. 2-1030 discloses a method using amorphous silica, Japanese Patent Application Publication No. 59-155095 discloses a method using calcium carbonate, and Japanese Patent Application Publication No. 59-155097 discloses a specific range of oil absorption. Methods using activated clay or calcined kaolin have been disclosed, but at present none of the methods has yielded sufficiently satisfactory results.

〔the purpose〕

An object of the present invention is to provide a heat-sensitive recording material that is free from sticking and debris adhesion problems and has excellent head matching properties.

〔composition〕

According to the present invention, there is provided a heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and a color developer, and is characterized in that it contains hydrated halloysite.

The hydrated halloysite used in the present invention is a clay mineral belonging to kaolin, and while kaolinite has a hexagonal plate-like particle shape, hydrated halloysite has a spherical particle shape, and has the characteristics of spherical kaolin. It is used for paper manufacturing, cosmetics, etc.

Kaolinite, which is generally used in heat-sensitive recording materials, has the above-mentioned hexagonal plate shape and is widely used because it is inexpensive, but it cannot be said to be satisfactory in terms of adhesion of residue to the thermal head. . On the other hand, the chemical composition of the hydrated halloysite used in the present invention is the same as that of kaolinite, but its most distinctive feature is that the particle shape is spherical, and when used as a heat-sensitive recording material, it is difficult to attach to a thermal head. It was found that the adhesion of scum was reduced.

In addition, hydrated halloysite is contained in the heat-sensitive coloring layer at 10 to 90% by weight, in the protective layer at 10 to 90% by weight, or in both layers at 10 to 90% by weight.
The effect is achieved by containing ~90% by weight, preferably 30-50% by weight in the thermosensitive coloring layer, 30-50% by weight in the protective layer, or 30-50% by weight in both layers. It will be demonstrated even more.

The leuco dyes used in the heat-sensitive layer of the present invention can be applied singly or in combination of two or more, and such leuco dyes include triphenylmethane-based and fluoran-based leuco dyes. Phenothiazine-based, auramine-based, spiropyran-based, etc. are preferred, and specific examples include those shown below.

3.3-bis(p-dimethylaminophenyl)-phthalide, 3.3-bis(p-dimethylaminophenyl)-6
-dimethylaminophthalide (also known as crystal violet lactone), 3.3-bis(p-dimethylaminophenyl)-6-dimethylaminostyryl, 3.3-bis(
p-dimethylaminophenyl)-6-chlorophthalide,
Methyl bis(p-dimethylaminostyryl)-γ-toluenesulfonate, bis(p-dimethylaminostyryl)
-methyl benzenesulfonate, bis(p-dimethylaminostyryl)-γ-methyl chlorobenzenesulfonate,
Methyl bis(p-dimethylaminostyryl)-〇-naphthalenesulfonate, methyl bis(p-dimethylaminostyryl)-β-naphthalenesulfonate, 3,3-bis[
2-(p-dimethylaminophenyl)-2-(p-methoxyphenyl)ethynyl)-4,5,6,7tetrachlorophthalide, 3,6bis(dimethylamino)fluorene-9-spiro-3'- 16'-dimethylamino)phthalide, 3-(4'-diethylamino-2'-methoxyphenyl)-3-1:(1''-p-dimethylaminophenyl-1''-phenyl)ethylene-2-yl]benzophthalide, 3-(4-dinithylamino-2°-methoxyphenyl)3-((1”'-p-dimethylaminophenyl-1per-dolyl)ethylene-2-yl]benzophthalide, 3-(4'-diethylamino-2'- methoxyphenyl) -3-C(1'"-p-dimethylaminophenyl-1"-phenyl)ethylene-2-yl]
Phthalide, 3-(4"-diethylamino-2'methoxyphenyl)-3-[(4"-p-dimethylaminophenyl-4perphenyl-1"°3"-butadien-1'-yl]phthalide, 3 -(4'-diethylamino-
2'-Methoxyphenyl)-3-[(4''-p-dimethylaminophenyl-4''-p-tolyl-1''', 3°-butadien-1''yl]phthalide, 3- (4'-
diethylamino-2"-methoxyphenyl)-3-C
(4”-p-dimethylaminophenyl-4”-p-chlorophenyl-1”, 3”-butadien-1”-yl)
Benzophthalide, 3-(4°-diethylamino-2′-
methoxyphenyl)-3-C(4'"-p-dimethylaminophenyl-4"-p--y engineering=#-1'"3 part-
Butadien-1-yl]benzophthalide, 2-methyl-3-chloro-6-(p((p-phenylaminophenyl)amine]phenyl)anilinofluorane, 3,3-
Bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlorofluorane, 3-dimethylamino-5,7-dimethylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-
7-methylfluorane, 3-diethylamino 7.8-benzfluorane, 3-diethylamino-6-methyl-7
-Chlorfluorane, 3-(N-p-tolyl-N-ditylamino)-6-methyl-7-anilinofluorane, 3
-pyrrolidino-6-methyl-7-anilinofluorane,
2(N-(3″-trifluoromethylphenyl)amino)-6-dinithylaminofluorane, 2(3,6-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam), 3- diethylamino-6-
Methyl-7-(m-trichloromethylanilino)fluoran, 3-diethylamino-7-(0-chloroanilino)fluoran, 3-dibutylamino-7-(0-chloroanilino)fluoran, 3-N-methyl-N-amylamino -6-methyl-7-anilinofluorane, 3-N-
Methyl-N-cyclohexylamino-6-methyl-7-
Anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-(N,N-diethylamino)-5-methyl7-(N,N-dibenzylamino)fluoran, benzoylleucomethylene blue, 6
“-chloro-8°-methoxy-benzoindolino-pyrylosvirane, 6′-bromo-3”-methoxy-benzoindolino-pyrylospirane, 3-(2”-hydroxy-4′-dimethylaminophenyl)-3-( 2′-methoxy-5”-chlorophenyl)phthalide, 3-(2′
-hydroxy-4'-dimethylaminophenyl)
-3-(2'-methoxy-5'-nitrophenyl)phthalide, 3-(2'-hydroxy-4"-diethylaminophenyl)-3-(2'-methoxy-5"-methylphenyl)phthalide, 3-(2'-methoxy-5'-methylphenyl)phthalide, “ -Methoxy-4゛-
dimethylaminophenyl)-3-(2“-hydroxy-
4=chloro-5"-methylphenyl)phthalide, 3-morpholino-7-(N-propyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-hood trifluoromethylanilinofluorane, 3-diethylamine-5
-Chloro-7-(N-benzyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-(di-p-
chlorphenyl)methylaminofluorane, 3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3-(N-ethyl-p-toluidino)
-7-(α-phenylethylamino)fluoran, 3-
Diethylamino-7-(o-methoxycarbonylphenylamino)fluoran, 3-diethylamine-5-methyl-7-(α-phenylethylamino)fluoran, 3
-diethylamino-7-biperisinofluorane, 2-chloro3-(N-methyltoluidino)-7-(p-n-
butylanilino)fluoran, 3-(N-benzyl-N
-cyclohexylamino)-5,6-penzo7-〇-
Naphthylamino-4'-bromofluorane, 3-diethylamino-6-methyl-7mesitidino 4', 5'
-benzofluorane, 3-diethylamino-6-methyl-7-(2'-dimethylanilino)fluoran, etc.

Further, as the coloring agent used in combination with the leuco dye in the present invention, various electron-accepting compounds or oxidizing agents that cause the leuco dye to develop special color upon contact are used. These are conventionally known, and specific examples thereof include inorganic acids, organic acids, phenolic substances, and phenolic resins as shown below.

Bentonite, zeolite, acid clay, activated clay, silica gel, phenolic resin, 4,4'-isopropylidene bisphenol, 4,4'-isopropylidene bis(
0-Methylphenol), 4.4°-Secondary-butylidenebisphenol, 4,4′-isopropylidenebis(0-tert-butylphenol), 4.4°-Cyclohexylidenediphenol, 4.4°-Secondary-butylidenebisphenol -isopropylidenebis(2-chlorophenol), 2,2゜-methylenebis(
4-methyl-6-tert-butylphenol), 4
．． 4'-Butylidene bis(6-tert-butyl-
2-methyl)phenol, 1,1.3-tris(2-methyl-4-hydroxy-5-tert-butylphenol)butane, 1,1.3-tris(2-methyl-4-
Hydroxy-5-cyclohexylphenyl)butane, 4
．． 4′-thiobis(6-tert-butyl-2-methyl)phenol, 4,4°-diphenolsulfone, 4
, 2'-diphenolsulfone, 4-isopropoxy-
4'-Hydroxydiphenylsulfone, 4-benzyloxy-4'-hydroxydiphenylsulfone, 4,4'
-diphenol sulfoxide, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1,7-bis(4-hydroxyphenylthio)-3 ,5-dioxahebutane, 1
．． 5-bis(4-hydroxyphenylthio)-3-oxapentane, 1,3-bis(4-hydroxyphenylthio)-propane, 2,2°-methylenebis(4-ethyl-6-shabutylphenol), 1. 3-bis(4-
hydroxyphenylthio)-2-hydroxypropane,
N,N"-diphenylthiourea, N,N-di(m-chlorophenyl)thiourea, salicylanilide, 5-chlorosalicylanilide, salicyl-〇-chloroanilide,
2-hydroxy-3-naphthoic acid, antipyrine complex of zinc thiocyanate, zinc salt of 2-acetyloxy-3-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-hydroxy-1-naphthoic acid, hydroxynaphthoic acid Metal salts such as zinc, aluminum, and calcium, bis(
4-hydroxyphenyl)acetic acid methyl ester, bis-
(4-hydroxyphenyl)acetic acid benzyl ester, 1
．． 3-bis(4-hydroxycumyl)benzene, 1,4
-Bis(4-hydroxycumyl)benzene, 2.4゛-
Diphenolsulfone, 3,3゛-diallyl-4,4'
-diphenolsulfone, α,α-bis(4-hydroxyphenyl)-〇-methyltoluene, antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, tetrabromobisphenol S, 3゜4-dihydroxy-
4'-methyldiphenylsulfone, etc.

In the present invention, 1. When a leuco dye and a coloring agent are bonded and supported on a support in order to obtain a heat-sensitive recording material, various conventional binders can be used as appropriate. Specific examples of such binders include the following.

Polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide/acrylic acid ester copolymer, acrylamide/acrylic acid ester/
In addition to water-soluble polymers such as methacrylic acid terpolymer, styrene/maleic anhydride copolymer alkali salt, imbutylene/maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, and casein, Emulsions such as vinyl acetate, polyurethane, polyacrylic ester, polymethacrylic ester, vinyl chloride/vinyl acetate copolymer, ethylene/vinyl acetate copolymer, styrene/butadiene copolymer, styrene/butadiene/acrylic copolymer Combined latex etc.

Furthermore, when obtaining a heat-sensitive recording material according to the present invention, various heat-fusible substances can be used as a heat sensitivity improver, if necessary, and specific examples thereof include the following compounds.

Fatty acids such as stearic acid and behenic acid, fatty acid amides such as stearic acid amide and palmitic acid amide, fatty acid metal salts such as zinc stearate, aluminum stearate, calcium stearate, zinc palmitate, and zinc behenate, p-benzyl Biphenyl, terphenyl, trinophenylmethane, benzyl p-benzyloxybenzoate, β-pencyloxynaphthalene, β-naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid Methyl ethyl, diphenyl carbonate, terephthalic acid dibenzyl ester, terephthalic acid dimethyl ester, 1,4-dimethoxynaphthalene, 1,4-jethoxynaphthalene, 14-dibenzyloxynaphthalene, 1.
2-bis(phenoxy)ethane, 1,2-bis(3-methylphenoxy)ethane, 1,2-bis(4-methylphenoxy)ethane, 1,4-bis(phenoxy)butane, 1,4-bis( phenoxy)-2-butene, 1,2-bis(4-methoxyphenylthio)butane, dibenzoylmethane, 1,4-bis(phenylthio)butane, 1.
4-bis(phenylthio)-2-butene, 1.2-bis(4-methoxyphenylthio)ethane, 1.3-bis(
2-vinyloxyethoxy)benzene, 1,4-bis(
2-vinyloxyethoxy)benzene, p-(2-vinyloxyethoxy)biphenyl, p-aryloxybiphenyl, p-propargyloxybiphenyl, dibenzoyloxymethane, 1°3-dibenzoyloxypropane, dibenzyl disulfide, 11 -diphenylethanol, 1゜1-diphenylpropertool, p-(benzyloxy)benzyl alcohol, 1,3-diphenoxy-
2-propertool, N-cutadezylcarbamoyl-p
-methoxycarbonylbenzene, N-octadecylcarbamoylbenzene, etc.

Further, in the present invention, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, surfactants, lubricants, pressure coloration inhibitors, etc., may be used in combination, if necessary. In this case, fillers include, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, and other inorganic fine powders such as surface-treated calcium and silica. , urea-formalin resin, styrene/methacrylic acid copolymer, polystyrene resin, etc. As lubricants, higher fatty acids and their metal salts, higher fatty acid amides, higher fatty acid esters, animal-based , various vegetable, mineral, or petroleum-based waxes.

The heat-sensitive recording material of the present invention is manufactured by, for example, coating a heat-sensitive layer-forming coating solution containing the above-mentioned components on a suitable support such as paper, synthetic paper, or plastic film and drying it, and is used in various recording fields. Applied.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples. Note that all parts and percentages shown below are based on weight.

Example 1 (Liquid A) 3-dibutylamino-6-methyl-7-anilinofluorane 20 parts 10%
Polyvinyl alcohol aqueous solution 20 parts water
60 parts (B liquid) Bisphenol A 25 parts p
-Benzyl biphenyl 20 parts 10% polyvinyl alcohol aqueous solution 45 parts water
35 copies (
Liquid C) Hydrated halloysite (HK Kakaon; manufactured by Kabe Mining Co., Ltd.) 10 parts 10
% polyvinyl alcohol aqueous solution 100 parts 20% zinc stearate dispersion 10 parts 12.5% surfactant-containing liquid 32 parts (interface 557H Dick's
(manufactured by Hercules) water
210 parts A heat-sensitive coloring layer prepared by dispersing the above A above upper liquid and B liquid using a sand mill so that the average particle diameter becomes 2 μm or less, and mixing them in a ratio of (A liquid): (B liquid) = 1: 2. The basis weight of the forming liquid is 52g/r.
The coating was dried on RF high-quality paper so that the coating amount after drying was 6 g/rrf. Next, (Liquid C) was prepared as a protective layer forming liquid, and it was coated and dried on the heat-sensitive layer coated paper so that the coating amount after drying was 3 g/bo, and the smoothness was about 500 seconds using a super calender. The recording material of the present invention was obtained by surface treatment as described above.

Comparative Example 1 A heat-sensitive recording material of Comparative Example 1 was obtained in the same manner as in Example 1, except that kaolin (Kaolin UW90; manufactured by Undo Kogyo ■) was used instead of the hydrated halloysite in Example 1.

Comparative Example 2 Instead of the hydrated halloysite in Example 1, urea-
A heat-sensitive recording material of Comparative Example 2 was prepared in the same manner as in Example 1 except that formalin resin powder was used.

Each of the heat-sensitive recording materials obtained as described above was subjected to a thermal printing simulator (manufactured by Matsushita Electronic Components) at an applied power of 0.6 W/dot and a current conduction time of 1.8 m S e C1.
1 line recording time 10m5ec, sub-scanning density 7,711
The following table shows the results of printing for 10 m at in/mm and examining the adhesion of residue and stinking noise.

*Color density was measured using a Macbeth densitometer (effect) The heat-sensitive recording material of the present invention has less head residue, no sticking, and excellent head matching properties.

Claims (3)

[Claims] (1) A heat-sensitive recording material having a heat-sensitive coloring layer containing a leuco dye and a color developer as main components, characterized in that the heat-sensitive coloring layer contains hydrated halloysite. (2) In a heat-sensitive recording material having a heat-sensitive color forming layer containing a leuco dye and a color developer as main components and a protective layer containing a water-soluble polymer binder as a main component, hydrated halloysite is contained in the protective layer. A heat-sensitive recording material characterized by: (3) The heat-sensitive recording material according to claim 1 or 2, wherein the hydrated halloysite is a spherical hydrated halloysite.