JPH022070A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material excellent in color forming sensitivity and generating no color shading or color return by containing a colorless or light-colored color forming compound and chlorinated polyolefin or rubber having specific chlorine content. CONSTITUTION:As chlorinated polyolefin, for example, polychloroethylene, polychloropropylene or the like are designated and, as chlorinated rubber, one prepared by chlorinating natural rubber, polyisobutylene rubber or the like is designated and the chlorine content of the chlorine-containing polymer is necessarily set to 20% or more, pref. 25% or more and one having a chlorine content of below 20% shows almost no effect as a coupler. As a colorless or light-colored color forming compound, for example, a triarylmethane type compound, a diphenylmethane type compound and a xanthene type compound used in a general thermal recording material are designated and several kinds of these dyes can be used before use.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heat-sensitive recording material, specifically, a heat-sensitive recording material having a chlorine content of 20 to 20.
The present invention relates to a heat-sensitive recording material containing 80% chlorinated polyolefin or chlorinated rubber as a color developer.

[Prior art and problems to be solved by the invention] A heat-sensitive recording medium is a method in which a color-forming substance that is normally colorless or light-colored and a surface coloring agent that develops color in the color-forming substance when subjected to the action of heat are multiplied in an isolated state. It is produced by coating the surface of a support such as paper, synthetic paper, plastic film or sheet together with a sensitizer, binder and other additives. Then, in the recording apparatus, when a heat generating element such as a thermal head or a hot pen comes into contact with this recording medium, the color-forming substance and the color developer react to form a color such as black, and the recording is performed.

Compared to other recording media, such recording media do not require complicated processing such as development and fixing, can be recorded using relatively simple equipment in a short time, and have low noise levels. Because of its advantages such as low generation, low environmental pollution, and low cost, it is useful for copying books, documents, etc., as well as for various types of recording paper, computers, facsimile machines, etc.
It is widely used as a recording material 181 for telex machines, ticket vending machines, prepaid cards, labels, etc.

Conventionally, color developers that thermally develop color from color-forming substances include:
Various acidic substances have been proposed, especially phenolic compounds, such as bisphenol A% p-hydroxybenzoic acid hensyl ester, 4゜4゛-cyclohexylidene diphenol, 1,1.3- °-T-tert-butyl-4-hydro-tray-6-methylphenyl)butane or organic carboxylic acid derivatives are used alone or in combination. However, when these acidic substances are used, the color development sensitivity is not yet sufficient, and there are drawbacks such as color unevenness, color reversion, or discoloration during storage.

Therefore, attempts have been made to achieve higher sensitivity by using a third substance, an aggravating agent, in addition to a chromogenic substance and a color developer. For example, 4-benzyloxybiphenyl,
It was proposed to use dimethyl phthalate, stearonic acid amide, phenyl benzoate, etc. in combination. However, although this improves the color development sensitivity to some extent, it is still not sufficient and causes color unevenness and color reversion, and further improvements have been desired.

In addition, if these heat-sensitive recording materials are stored in a bag made of vinyl chloride, if the heat-sensitive recording material comes into contact with a desk mat made of vinyl chloride, or if the heat-sensitive recording material is touched by hand, the plasticity in the vinyl chloride may be released. There was a problem that the coloring area would fade due to migration of the agent or oil from hands and fingers.

The surface of the heat-sensitive recording material is coated with plasticizers and oils that do not penetrate.
It has also been proposed to form an overcoat layer, but this method has the drawbacks of increasing costs and making it difficult to print on the overcoat layer, making it difficult to implement as a practical method.

For this reason, in Japanese Patent Application Laid-open No. 59-682'lG,
It has been proposed to use a water-insoluble polymer having a carboxyl group in the molecule as a color developer, but since the portion that functions as a color developer is a carboxylic acid, this method eliminates the aforementioned disadvantages of color unevenness and color fading. I couldn't do that.

Therefore, the object of the present invention is to provide a material that not only has excellent color development sensitivity, but also has excellent storage stability and solvent resistance without color unevenness or color fading, and does not fade even when it comes in contact with plasticizers or oils. The purpose of the present invention is to provide heat-sensitive recording materials.

[Means to solve the problem]

As a result of extensive studies, the inventors of the present invention have found that by using a specific chlorine-containing polymer with a specific chlorine content, it is possible to not only improve printing speed and significantly improve color development sensitivity, but also improve solvent resistance and It also significantly improves storage stability;
That is, it was found that the above object was achieved.

The present invention was made based on the above findings, and consists of a color-forming compound that is usually colorless or light-colored, and a chlorine content of 20 to 80%.
% of chlorinated polyolefin or chlorinated rubber.

Hereinafter, the heat-sensitive recording material of the present invention will be explained in detail.

Examples of the chlorinated polyolefin used in the present invention include chlorinated polyethylene, chlorinated polypropylene, and chlorinated polybutene, and examples of the chlorinated rubber include chlorinated rubber obtained by chlorinating natural rubber, polyisoprene rubber, etc. .

These chlorine-containing polymers can be produced, for example, by dissolving a polymer such as polyolefin, natural rubber, or polyisoprene rubber in a solvent and chlorinating it, by swelling the above polymer with a solvent and chlorinating it, or by preparing a fine powder of the above polymer. This can be carried out by well-known methods such as a method of suspending the polymer in water and chlorinating it, and a method of chlorinating a fine powder of the polymer in a chlorine gas stream, and in both cases, commercially available products can be used as they are.

The chlorine content of the above chlorine-containing polymer is required to be 20% or more, more preferably 25% or more, in order to achieve the object of the present invention, and those with a chlorine content of less than 20% are used as a color developer. It shows almost no effect.

Moreover, even if the polymer has a chlorine content of 20% or more,
Both polyvinylidene chloride (73% chlorine content) and polyvinyl chloride (57% chlorine content) show almost no effect as a color developer, and the effect of the present invention is only achieved when a specific chlorine-containing polymer is used. It is something that is played.

The above-mentioned chlorine-containing polymer used in the present invention has excellent effects as a color developer even when used alone, but the color development sensitivity can be improved by using it in combination with an exacerbating agent. It is preferable to use agents together.

Examples of the sensitizers that can be used in combination with the chlorine-containing polymer include zinc acetate, zinc octylate, zinc laurate, zinc stearate, zinc oleate, zinc hehenate, zinc benzoate, zinc salicylate dodecyl ester salt,
Calcium stearate, Magnesium stearate,
Metal organic acid salts such as aluminum stearate, amide compounds such as stearamide, stearoyl urea, acetanilide, acetoacetanilide, benzoic acid stearylamide, ethylene bisstearic acid amide, hexamethylene bisoctylic acid amide, m-terphenyl, 1.2
-bis(3-methylphenoxy)ethane, p-hensylbiphenyl, p-hensyloxybiphenyl, diphenyl carbonate, bis(4-methylphenyl)carbonate, dihenzyl oxalate, ■-hydroxy-2-naphthalenecarboxylic acid fluoride hensyl 1-hydroxy-2-naphthalenecarboxylate, phenyl 3-hydroxy-2-naphthalenecarboxylate, 3-hydroxy-2-naphthalenecarboxylic acid anilide, methylene dibenzoate,
1.4-bis(2-vinyloxyethoxy)benzene, 2
-benzyloxynaphthalene, benzyl 4-benzyloxybenzoate, dibenzyl terephthalate, dibenzoylmethane, etc., and amide compounds and/or metal organic acid salts are particularly preferred because of their great effects.

Furthermore, a conventionally known color developer can be used in combination with the chlorine-cooperative polymer. The above-mentioned chlorine-containing polymer also has an excellent effect of improving storage stability, so that even when used in combination with other color developers, problems such as color reversion and discoloration do not occur.

Conventionally known color developers that can be used in combination with the above chlorine-containing polymer include, for example, p-octylphenol, p-tert-butylphenol, p-phenylphenol, p-hydroxyacetophenone, α-naphthol, β-naphthol, P-tertiary Octylphenol, 2,2"-dihydroxybiphenyl, bisphenol A, 1,1-bis(P
-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis-(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl- 4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxy-3-allylphenyl)sulfone, bis(3 ,4-dihydroxyphenyl)
Sulfone, 1.1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)ether, 1.1.3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1 , 1.3-) Lis(2-methyl-4hydroxy-5-cyclohexylphenyl)butane, Bis[2-(4-hydroxytunylthio)ethoxy]methane, 4-(4-isopropoxybenzenesulfonyl)phenol , 4-hydroxyphthalic acid dimethyl ester, bis(4-hydroxyphenyl)
Examples include phenols and organic carboxylic acids such as acetic acid M butyl ester, Hensyl p-hydroxybenzoate, and 3,5-di-tert-butylsalicylic acid.

In addition, various dyes are well known as the normally colorless to light-colored color-forming compound used in the present invention, and there are no particular limitations as long as they are used in general heat-sensitive recording materials.

Specific examples of these dyes (color-forming compounds) are (
1) Triarylmethane compounds; for example, 3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (crystal violin raftone), 3-
(p-dimethylaminophenyl)3-(2-phenyl-3-indolyl)phthalide, 3-(p-dimethylaminophenyl)3-(1,2-dimethyl-3-indolyl)phthalide, 3,3-bis( 9-Ethyl-3-carbazolyl)-5-dimethylaminophthalide, 3,3bis(2
-phenyl-3-indolyl)-5-dimethylaminophenylde, etc., (2) diphenylmethane compounds; for example, 4,4-bis(dimethylamino)benzhydrin benzyl ether, N~2°4.5-1- +J N-halophenyl leuco auramine'J such as dichlorohenyl leuco auramine, (3) xanthene compounds; for example, rhodamine-β-anilinolactam, 3-diethylamino-7
-Octylaminofluorane, 3-diethylamine-7
-(2-chloroanilino)fluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-chloro-7-(β-ethoxyethylamino)fluoran, 3-piperidino-6-methyl- 7-
Anilinofluorane, 3-ethyltolylamino-6-methyl-7-anilinofluorane, 3-cyclohexylmethylanilino-6-methyl-7-anilinofluorane,
3-diethylamino-6-chloro-1-T-chloropropylaminofluorane, etc., (4) thiazine compounds; examples, t, hendiyl leucomethylene blue, p-nitrobenzoyl leucomethylene blue, etc., (5) spiro compounds; For example, 3-methylspirodinaphthopyran, 3-
Examples include ethylspirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho-(3-methoxybenzo)spiropyran, and several types of these dyes may be used in combination.

The chlorine-containing polymer and color-forming compound used in the present invention are usually atomized using a grinder such as a ball mill, attrizer, or sand grinder, or a suitable emulsifier, and then coated with various additive materials depending on the purpose. Make it into a liquid.

This coating solution usually contains polyvinyl alcohol, hydroxyethylcellulose, methylcellulose, polyacrylamide polymer, starch, styrene-maleic anhydride copolymer, vinyl acetate-maleic anhydride copolymer, styrene-
Binder such as butadiene copolymer, filler such as kaolin, silica, diatom, talc, titanium dioxide, calcium carbonate, magbusium carbonate, aluminum hydroxide, etc. are blended, and in addition, metal such as carunium stearate. Soaps, waxes, light stabilizers, waterproofing agents, liquid splitting agents, antifoaming agents, fillers, etc. can be added.

By applying this coating liquid to paper and various films, the desired heat-sensitive recording material can be obtained.

The amount of the chlorine-containing polymer used in the present invention is:
There is no particular limitation, as it varies depending on the required performance and recording suitability as well as the type and amount of other additives used, but usually 0 parts by weight of the color-forming compound.
01 to 10 parts by weight.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example-1 20 g of 2-anilino-3-methyl-6-dinithylaminofluorane was dissolved in 10% polyvinyl alcohol (tA
The dye dispersion (
Solution A) was obtained.

20 g of the sample compound (see Table 1 below) was ground in a ball mill with 100 g of a 10% polyvinyl alcohol aqueous solution to obtain a color developer dispersion (liquid B).

20g of acetoacetanilide in 10% polyvinyl alcohol water? Grind in a ball mill with 100g of liquid,
A lik solution for exacerbation (liquid C) was obtained.

Mix liquid A, liquid B, and liquid C at a weight ratio of 1:2:3. 50 g of calcium carbonate was added and dispersed to 200 g to obtain a coating liquid.

This coating liquid was coated on a base paper of 50 g/n (solid content) to a coating amount of 6 g/M and dried to produce a heat-sensitive recording paper.

Using the obtained thermal recording paper, the color density of the recorded image printed using a commercially available thermal facsimile machine (Panafax UF2: Matsushita Electric!!!) was measured using a Maches densitometer (Model RD-933, Maches Co., Ltd.).

In addition, the above heat-sensitive recording paper was heated at 50°C and 90% humidity, and after stamping with dioctyl phthalate at 50°C.
The paper was stored for 48 hours under dry conditions under two-line conditions, and the density of the background after storage and the density after printing were measured in the same manner.
From the second sample onward, the remaining density of the printed area after storage was measured.

The results are shown in Table 1 below.

*l: Highly chlorinated polypropylene (chlorine content 67%, made by Asahi Denka Kogyo Co., Ltd.) *2: Highly chlorinated polypropylene (chlorine content 65%, made by Asahi Denka Kogyo Co., Ltd.) *3: Highly chlorinated polyethylene ( Chlorinated polyethylene (chlorine content 65%, manufactured by Asahi Denka Kogyo Co., Ltd.) *4: Chlorinated polyethylene (chlorine content 30%, manufactured by Showa Denko Co., Ltd.) *5; Chlorinated polyethylene (chlorine content 40%, manufactured by Showa Denko Co., Ltd.) ) *6: Chlorinated natural rubber (chlorine content 66%, manufactured by Asahi Denka Kogyo Co., Ltd.) Example -
2 20 g of 3-dibutylamino-7-(2-chlorophenyl)aminofluorane was ground in a ball mill with 100 g of a 10% polyvinyl alcohol aqueous solution to obtain a dye dispersion (liquid A).

10 g of bisphenol A was ground in a ball mill with 100 g of a 10% polyvinyl alcohol aqueous solution to obtain a color developer dispersion (liquid B).

10 g of the sample compound (see Table 2 below) was ground in a ball mill with 1100 g of 10% polyvinylated polyvinyl acetate (C'/19) to obtain a liquid (C'/19) in color developer fraction 11.

20 g of stearic acid amide was ground in a ball mill with 100 g of a 10% polyvinyl alcohol aqueous solution to obtain a sensitizer dispersion (liquid D).

Mix A liquid, B liquid, C liquid, and D liquid at an ffi ratio of 1:1:1:3, and add 50 g of calcium carbonate to 200 g of the mixed liquid.
8 was added and dispersed to obtain a coating liquid.

Using this coating liquid, Anger Record n paper was prepared in the same manner as in Example-1, and the same tests as in Example-1 were conducted.

The results are shown in Table 2 below.

Example-3 20 g of 3-(N-cyclohexyl-N-methylamino)6-methyl-7-anirithufluorane was ground in a ball mill with 1.00 g of a 10% polyvinyl alcohol aqueous solution to obtain a dye dispersion ( Solution A) was obtained.

20 g of highly chlorinated polypropylene (ADEKAPREN CP3S, chlorine content 67%, manufactured by Asahi Denka Kogyo Co., Ltd.) j5) powder
was ground in a ball mill with 100 g of 10% polyvinyl alcohol to obtain a color developer dispersion (B).

As shown in Table 3 below, 20 g of the sensitizer was crushed in 10% polyvinyl alcohol to obtain a sensitizer dispersion (Cl).

A liquid, Btj. and C liquid were mixed at an ffl star ratio of 1:2:3, and 50 g of calcium carbonate was added to 200 g of the mixed liquid and dispersed to obtain a coating liquid.

Using this coating liquid, heat-sensitive recording paper was prepared in the same manner as in Example-1, and the same tests as in Example-1 were conducted.

The results are shown in Table 3 below.

From the results in Tables 1, 2, and 3, the following is clear.

The heat-sensitive recording material using the specific chlorine-containing polymer of the present invention not only has excellent color development sensitivity but also extremely excellent storage stability.

On the other hand, chlorinated polypropylene, which has a low chlorine content even if it is a chlorine-containing polymer, or polyvinylidene chloride and polyvinyl chloride, which have a high chlorine content, have almost no effect as a color developer and have poor storage stability. It is clear that the effect of using the specific chlorine-containing polymer of the present invention is extremely specific.

〔Effect of the invention〕

The heat-sensitive recording material of the present invention not only has excellent color development sensitivity, but also has excellent storage stability and solvent resistance, without color unevenness or color fading, and does not fade even if it comes into contact with plasticizers or oils. It is something.

Claims (1)

[Claims] Usually colorless to light colored compound and chlorine content 2
A heat-sensitive recording material characterized in that it contains 0 to 80% of chlorinated polyolefin or chlorinated rubber.