JPH02200480A - Thermal recording material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a heat-sensitive recording material, and more specifically, a heat-sensitive recording material in which a heat-sensitive coloring layer containing a leuco dye and a color developer as main components is provided on a support. Regarding improvement of materials.

[Conventional technology]

Recently, various recording materials have been researched and developed and put into practical use in the information recording field, in response to social demands such as diversification and increase in information, resource conservation, and pollution-free technology.Among them, thermal recording materials are (1) A colored image is recorded simply by heating, eliminating the need for a complicated developing process. (2) It can be produced using a relatively simple and compact device, and the resulting recording material can be easily handled. Easy and low maintenance costs.

(3) Paper is often used as a support, and in this case, the cost of the support is not only low, but also the feel of the resulting recorded material is similar to that of plain paper. In the field of printers such as tablets and calculators, and in the field of recorders for medical measurement.

It is widely used in the fields of low and high speed facsimiles, automatic ticket vending machines, thermal copying, etc.

The above-mentioned heat-sensitive recording material is manufactured by applying a coating liquid for forming a heat-sensitive coloring layer containing a coloring component capable of causing a coloring reaction by heating onto a support such as ordinary paper, synthetic paper, or synthetic resin film and drying the material. I'm here.

A colored image is recorded on the heat-sensitive recording material thus obtained by heating it with a thermal pen or a thermal head. As a conventional example of such a heat-sensitive recording material, for example,
Examples include the heat-sensitive recording materials disclosed in Japanese Patent Publication No. 3-4160 and Japanese Patent Publication No. 45-14039. However, such conventional heat-sensitive recording materials have, for example, low thermal responsiveness and are difficult to obtain sufficient color density during high-speed recording. I couldn't.

As a method to improve this drawback, for example, 3-N-methyl-N-cyclohexylamino-6-
Methyl-7-anilinofluorane
120), 3-dibutylamino-6-methyl-7
- By using a highly sensitive dye such as anilinofluorane (Japanese Unexamined Patent Publication No. 59-190891), or by using 1,7-bis(4-hydroxyphenylthio) as a color developer.
-3,5-dioxahebutane (JP-A-59-10645
6), 1゜5-bis(4-hydroxyphenylthio)-3-oxapentane (JP-A-59-116262)
It has been proposed to increase the speed and sensitivity by using a substance with good coloring properties, such as those disclosed in Japanese Patent Publication No. Also, JP-A-61-123584, JP-A-61-215087
In Japanese Patent Laid-Open No. 61-242889, attempts have been made to increase speed and sensitivity by using a combination of the above-mentioned substances.

[Problem to be solved by the invention]

However, although such heat-sensitive recording materials have high sensitivity, they generally tend to develop color due to pressure or friction, and color may develop during vibration or handling during transportation, reducing commercial value, or the image may deteriorate when handled after recording. It has the disadvantage of causing damage to the

Accordingly, an object of the present invention is to provide a heat-sensitive recording material that improves the above-mentioned conventional drawbacks, that is, to provide a heat-sensitive recording material that is highly sensitive and prevents color development due to pressure or friction.

[Means to solve the problem]

According to the present invention, in a heat-sensitive recording material in which a heat-sensitive coloring layer containing a leuco dye and a color developer as main components is provided on a support,
A heat-sensitive recording material characterized in that a cationic resin is used as a binder is provided.

- The binders used in thermal recording materials for boat fishing are anionic or nonionic, and cationic binders are not used because they tend to aggregate easily. However, 1
It has been found that by using a weak cationic resin or a modified cationic resin as a binder, aggregation is less likely to occur and it is highly effective in preventing color development due to pressure and friction after coating and drying. The reason for this is not clear at present, but it is probably because the protective colloidal properties, especially the protective colloidal properties against the color developer, are large, so that the coloring reaction caused by contact with the leuco dye can be suppressed.

Examples of the cationic resin used in the present invention include those in which an alkylamine or a quaternary alkyl ammonium salt is introduced into a known binder, and many types of these are commercially available. For example, C Polymer manufactured by Kuraray Co., Ltd. is used as the cationic polyvinyl alcohol, Excel series manufactured by 8 Star Chemical Co., Ltd. is used as the cationic starch, HD-501C manufactured by Toagosei Chemical Co., Ltd. is used as the acrylic resin, and Boncourt SFC manufactured by Dainippon Ink and Chemicals Co., Ltd. is used as the acrylic resin. series, NS-500 manufactured by Kindai Kagaku Co., Ltd., Kikoat 5S-300, etc., but the present invention is not limited to these, and is characterized by having cationic properties.

In addition, in the present invention, it is preferable to use a weakly anionic or nonionic resin, which is commonly used as a binder, in order to prevent agglomeration. Preferably by weight.

This ratio varies depending on the strength of cationicity of the cationic resin used, and the stronger the cationicity, the more likely it is to aggregate, so a larger amount of resin is required. However, as the amount of cationic resin decreases, the effect naturally decreases.

As the binder used in combination in this case, various commonly used binders can be used, but care must be taken when using a strongly anionic binder because the resins will aggregate together.

Specific examples of the binder used in combination include the following.

Polyvinyl alcohol, starch and its derivatives, hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, cellulose derivatives such as 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, isobutylene/maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, and casein, polyacetic acid vinyl, polyurethane, polyacrylic acid,
polyacrylic ester, polymethacrylic ester,
Emulsions such as vinyl chloride/vinyl acetate copolymers, ethylene/vinyl acetate copolymers, and styrene/butadiene copolymers.

Latex such as styrene/butadiene/acrylic copolymer.

The leuco dyes used in the present invention may be applied singly or in a mixture of two or more types. As such leuco dyes, those applied to this type of heat-sensitive material may be arbitrarily applied. For example, triphenyl Methane type, fluorane type, phenothiazine type.

Leuco compounds of dyes such as auramine, spiropyran, and indolinophthalide are preferably used. Specific examples of such leuco dyes 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-diethylaminophenyl, 3.3-bis (P-dimethylaminophenyl)-6-chlorophthalide, 3.3-bis(P-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlorofluoran, 3-dimethylamino-5,7-dimethylfluoran ,3
-N-methyl-N-imbutyl-6-methyl-7-anilinofluorane, 3-N-ethyl-N-isoamyl-6-methyl-7-anilinofluorane, 3-diethylamino-7-chlorofluorane , 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane.

3-diethylamino-6-methyl-7-chlorofluorane, 3-(N-p-tolyl-N-ethylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7- Anilinofluorane.

2- (N-(3'-trifluoromethylphenyl)
amino)-6-dinithylaminofluorane.

2-(3,6-bis(diethylamino)-9-(o-
chloranilino)xantylbenzoic acid lactam), 3-
Diethylamino-6-methyl-7-(trichloromethylanilino)fluoran, 3-diethylamino-7-(o-chloroanilino)fluoran, 3-dibutylamino-7-(o-chloroanilino)fluoran, 3-N-methyl -N-amylamino-6-methyl-7-
Anilinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane.

3-diethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-(2',4'-
dimethylanilino)fluoran, 3-(N,N-diethylamino)-5-methyl-7-(
N,N-dibenzylamino)fluoran, benzoylleucomethylene blue 6'-chloro-8'-methoxy-benzoindolino-pyrylospirane, 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-41-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl) phthalide, 3-(2'-methoxy-4'-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'
-methylphenyl)phthalide, 3-morpholino-7-(N-propyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-( N-benzyl-trifluoromethylanilino)fluorane.

3-pyrrolidino-7-(di-P-chlorophenyl)methylaminofluorane.

3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3-(N-ethyl-P-toluidino)-7-(α-phenylethylamino)fluorane, 3-diethylamino-7-(o -methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl-7-(α-phenylethylamino)fluoran.

3-diethylamino-7-piperidinofluorane, 2-
Chloro-3-(N-methyltoluidino)-7-(p-n
-butylanilino)fluoran, 3- (N-methyl-N-isopropylamino)-6-
Methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3.6-bis(dimethylamino)fluorene spiro(9
゜3')-6'-dimethylaminophthalide, 3-(N
-benzyl-N-cyclohexylamino)-5,6-penzo 7-α-naphthylamino-4'bromofluorane.

3-diethylamino-6-chloro-7-anilinofluorane.

3-N-ethyl-N-(2-ethoxypropyl)amino-6-methyl-7-anilinofluorane.

3-N-ethyl-N-tetrahydrofurfurylamino-
6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-mesitidino 4', 5'-benzofluorane, and the like.

In addition, the color developer used in the present invention includes various electron-accepting compounds that cause the leuco dye to undergo catalytic color development, such as phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids, and metal salts thereof. It is preferably applied, and specific examples include those shown below.

4.4'-Isopropylidene bisphenol.

4.4'-Isopropylidene bis(O-methylphenol).

4.4'-Secondary-butylidenebisphenol 4.4'-Isopropylidenebis(2-tertiary-
butylphenol) 5 4.4'-cyclohexylidene diphenol, 4.4'
-isopropylidene bis(2-chlorophenol), 2.2'-methylenebis(4-methyl-6-tert-butylphenol), 2.2'-methylenebis(4-ethyl-6-tert-butylphenol), 4.4 '-butylidenebis(6-tert-butyl-2-methylphenol), 1.1.3-)lis(2-methyl-4-hydroxy-
5-tert-butylphenyl)butane, 1.1.3-
Tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane.

4.4'-thiobis(6-tert-butyl-2-
methylphenol), 4.4'-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, 1,3-bis(4-hydroxyphenylthio) -2-hydroxypropane, N,N'-diphenylthiourea.

N,N'-di(m-chlorophenyl)thiourea, salicylanilide, 5-chloro-salicylanilide, salicyl-〇-chloroanilide, 2-hydroxy-3-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1 -Hydroxy-2-naphthoic acid, zinc, aluminum of hydroxynaphthoic acid.

Metal salts such as 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, 3.4-dihydroxy-4'-methyldiphenylsulfone, α,α-bis(4-hydroxyphenyl)-α-methyltoluene.

Antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, tetrabromobisphenol S, etc.

In the present invention, in addition to the leuco dye and color developer, if necessary, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, surfactants, thermofusible substances (or lubricants), may be used. ) etc. can be used together. In this case, examples of fillers include calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide,
Barium sulfate.

Examples include inorganic fine powders such as clay, talc, and surface-treated calcium and silica, as well as organic fine powders such as urea-formalin resin, styrene/methacrylic acid copolymer, and polystyrene resin. Examples of thermofusible substances include higher fatty acids or their esters, amides, or metal salts, various waxes, condensates of aromatic carboxylic acids and amines, benzoic acid phenyl esters, higher linear glycols, , 4-epoxy-dialkyl hexahydrophthalate, higher ketone, P-toluenesulfonic acid phenyl ester, 1,2-bis(3-methylphenoxy)ethane, P-benzylbiphenyl, 1,4-bis(vinyl) Examples include oxyethyloxy)benzene and other heat-fusible organic compounds.

The heat-sensitive recording material of the present invention can be produced, for example, by applying a coating liquid for forming a heat-sensitive coloring layer containing each of the above-mentioned components onto a suitable support such as paper, synthetic paper, or plastic film, drying it, and subjecting it to calender treatment. It is obtained by In this case, an undercoat layer may be provided below the thermosensitive coloring layer, and an overcoat layer may be provided above. In addition, leuco dye, color developer,
The amounts of other auxiliary additives to be used are 5 to 40% by weight, 20 to 60% by weight, and 20 to 60% by weight, respectively.

〔Effect of the invention〕

The heat-sensitive recording material of the present invention suppresses fading color development due to pressure, friction, etc., and can be applied to high-speed recording with improved color development sensitivity, making it extremely practical.

〔Example〕

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples. Note that all parts and percentages shown below are based on heavy fik standards.

Example 1 [Liquid A] and [Liquid 8] were prepared by pulverizing and dispersing mixtures having the following compositions for 2 to 5 hours using a sand mill.

[Liquid A]

3-dibutylamino-6-methyl-7-anilinofluorane 20 parts 10% aqueous solution of cation-modified polyvinyl alcohol (trade name C-31,8: manufactured by Kuraray Co., Ltd.) 20
Department water
60 parts [Liquid B] Calcium carbonate 10 parts Water
60 parts Next, a coating liquid for forming a heat-sensitive coloring layer was prepared by mixing and stirring at a ratio of (Liquid A): [Liquid B) = 1:8, and this was dried on a high-quality paper with a basis weight of 47 g/I. After coating and drying to a coating weight of 3.0 g/m, calendering was performed to obtain a thermal recording paper of the present invention.

Example 2 In the same manner as in Example 1, the following [Liquid C] was prepared.

[Liquid C]

p-benzylbiphenyl 20 parts water
6
Part 0 Next, [Liquid A]: [Liquid B]: [Liquid C) = 1:8:1
After mixing and stirring at the ratio of , a coating solution for forming a heat-sensitive coloring layer was prepared.

A thermosensitive recording paper of the present invention was obtained in the same manner as in Example 1.

Example 3 In Example 1, except that cationic starch (trade name Excel D!1; manufactured by Nippon Star Chemical Co., Ltd.) was used instead of cationically modified polyvinyl alcohol to prepare [Liquid A] and [Liquid B], A thermosensitive recording paper of the present invention was obtained in the same manner as in Example 1.

Example 4 In Example 1, general polyvinyl alcohol (trade name PVA-117; manufactured by Kuraray Co., Ltd.) was used instead of the cation-modified polyvinyl alcohol in [Liquid A], and in place of the cation-modified polyvinyl alcohol in [Liquid B]. A thermosensitive recording paper of the present invention was obtained in the same manner as in Example 1, except that 10 parts of a cation-modified acrylic resin (trade name 110-501C; manufactured by Toagosei Kagaku Kogyo Co., Ltd.) and 10 parts of polyacrylamide were used.

Comparative Example 1 In Example 1, general polyvinyl alcohol (trade name: PVA) was used instead of cation-modified polyvinyl alcohol.
A heat-sensitive recording material for comparison was obtained in the same manner as in Example 1, except that Example 1 was used.

Comparative Example 2 In Example 3, oxidized starch (
A comparative thermal recording paper was obtained in the same manner as in Example 3, except that Sunsizer 600 (trade name, manufactured by Ajinomoto Co., Ltd.) was used.

The quality evaluation described below was carried out using the thermal recording paper of the present invention and the comparative thermal recording paper obtained as described above. The results are shown in Table-1.

(1) Dynamic color development A thermal printing experimental device with a thin film head manufactured by Matsushita Electronics Parts ■ was used, with a head power of 0.451/dot, 1 line recording time of 20 m5ec/1ine, and a scanning line density of 8 x 3.
Under the condition of 85 dots/mm, the pulse width was set to 0.2.0.6.
and 1.0 m5ec, and the print density was determined to 81 using a Macbeth densitometer RD-914.

(2) Wrap two pieces of heat-sensitive recording paper for friction color evaluation around a 100+a roll product, pack it unwrapped in a gift box for each person, and use a vibration tester to test the paper at an amplitude of 5cm and a rotation speed. A test was conducted for 1 hour at 600 rpm, and the color development of the roll surface was visually evaluated.

Table 1 Δ: Slightly colored, but practically acceptable level Resistant to discoloration caused by friction, etc.
Furthermore, since the color development property is not impaired, it can be applied to high-sensitivity heat-sensitive recording materials and is therefore extremely useful.

Patent applicant Rico Co., Ltd.

Claims (1)

[Claims] (1) A heat-sensitive recording material comprising a heat-sensitive color forming layer containing a leuco dye and a color developer as main components on a support, characterized in that a cationic resin is used as a binder.