JPS6235874A - Thermal recording material - Google Patents

Abstract

PURPOSE:To prevent paper jam or overlapped feed from occurring even under hot and humid conditions when feeding a thermal recording material one sheet at a time with an automatic paper-supplying mechanism, by providing an undercoat layer comprising a system polymer having an aliphatic quaternary ammonium group and a wax having a melting point not lower than a specified temperature, beneath a thermal recording layer. CONSTITUTION:A layer comprising a styrene polymer having an aliphatic quaternary ammonium group and a wax having a melting point of not lower than 60 deg.C is provided beneath the thermal recording layer as the undercoat layer. The styrene polymer may be, for example, a block copolymer of a styrene having an aliphatic quaternary ammonium group with a styrene monomer. In providing the undercoat layer, the ratio of the amount of the styrene polymer to the amount of the wax is preferably 1:5-5:1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and a color developer.

[Prior art]

A thermosensitive recording material is a recording material having a structure in which a so-called thermosensitive coloring layer that develops color when heated is formed on a support such as paper, synthetic paper, or resin film, and a thermal head is used for heating to develop the color. A built-in thermal printer is used. Compared to other recording materials, such recording materials can produce records in a short time using relatively simple equipment without complex processes such as development and fixing, and are less likely to generate noise or pollute the environment. Due to its advantages such as the absence of paper and low cost, it is used not only for copying books and documents, but also as a recording material in various fields such as electronic computers, facsimiles, ticket vending machines, labels, and recorders. Thermochromic compositions used in such heat-sensitive 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, a composition having a lactone, lactam or spiropyran ring Colorless or light-colored leuco dyes are used, and various acidic substances such as organic acids and phenolic substances are used as color developers. A recording material that combines a color former and a color developer has the advantage that the resulting image has a particularly clear color tone, a white background, and the image (dye image) has excellent weather resistance. , is widely used.

However, when such thermal recording materials are thermally printed one sheet at a time using a recording device with an automatic paper feeding mechanism, the coefficient of friction between the thermal recording materials and between the thermal head or platen roll decreases. As it gets bigger,
Static electricity is generated.

For this reason, during paper feeding, paper jams or two to four sheets being fed in layers may occur, which may cause failures in the thermal head section or the paper feeding section.

It is known that such development occurs significantly due to changes in environmental conditions, such as changes in temperature and humidity, and it was hoped that this problem could be solved.

〔the purpose〕

An object of the present invention is to provide a thermal recording material that does not cause paper jams or multilayer feeding even under high temperature and high humidity conditions when performing thermal printing while feeding sheets one by one using an automatic paper feeding mechanism.

〔composition〕

According to the present invention, in a heat-sensitive recording material having a heat-sensitive recording layer provided on a support, a styrene polymer containing an aliphatic quaternary ammonium group and a melting point of 60° C. are disposed under the heat-sensitive recording layer.
A heat-sensitive recording material is provided which is characterized by being provided with an undercoat layer made of the above wax.

The heat-sensitive recording material of the present invention uses a layer consisting of a styrene polymer containing an aliphatic quaternary ammonium group and a wax having a melting point of 60°C or more as an undercoat layer, so that it can prevent paper jams during paper feeding. No problem with multi-layer feeding occurs.

Examples of the styrenic polymer containing an aliphatic quaternary ammonium group used in the present invention include:
Conventionally known substances such as a block copolymer of styrene and styrene monomer having an aliphatic quaternary ammonium group can be used. Further, as the wax, known waxes having a melting point of 60°C or higher can be used, and preferred ones include:
Bis fatty acid amides such as ethylene bisoleic acid amide and ethylene bislauric acid amide, N-butyl-N'-
Substituted urea such as stearyl urea, substituted amide, or paraffin wax, microcrystalline wax, slack wax, aristowax.

Examples include petroleum waxes such as ceresin wax and montan wax. When forming an undercoat layer,
It is preferable that the composition ratio of the styrene polymer containing the aliphatic quaternary ammonium group and the wax having a melting point of 60° C. or higher is 1:5 to 5:1. In addition, when a wax with a melting point of 60°C or less is used as the undercoat layer, under various environmental conditions, especially under high temperature and high humidity, stickiness between the heat-sensitive recording sheets may occur, as shown in the comparative example below. Not enough effect.

The leuco dyes used in the present invention can be applied singly or in combination of two or more types, but such leuco dyes include:
Any of those applied to this type of heat-sensitive material may be used. For example, leuco compounds of dyes such as triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, and spiropyran-based dyes are preferably used. Specific examples of such leuco dyes include those shown below.

3.3-bis(p-dibutylaminophenyl)-phthalide.

3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone), 3.3-bis(p-dimethylaminophenyl)-6-dibutylaminophenyl.

3.3-bis(p-dimethylaminophenyl)-6-chlorophthalide, 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-chlorofluorane, 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-(o- 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-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-(N,N- diethylamino)-5-methyl-7-(
N,N-dibenzylamino)fluorane, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylospirane.

6'-Bromo-3'-methoxy-benzoindolino-pyrylospirane.

3-(2'-Hydroxy-41-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-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)fluoran, 3-pyrrolidino-7-(di-P-chlorophenyl)methylaminofluorane, 3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3 -(N-ethyl-P-toluidino)-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-(0-methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl-7-(α -phenylethylamino)fluorane, 3-diethylamino-7-piperidinofluorane, 2-
Chloro-3-(N-methyltoluidino)-7-(p-n
-butylanilino)fluorane, 3-(N-benzyl-cyclohexylamino)-5,6
-Penzo 7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino 4
',5'-benzofluorane etc.

Further, as the color developer used in the heat-sensitive coloring layer of the present invention, various electron-accepting substances that react with the leuco dye and color it when heated are used, and specific examples thereof are as follows. Examples include phenolic substances, organic or inorganic acidic substances, and salts thereof as shown below.

gallic acid, salicylic acid, 3-isopropylsalicylic acid,
3-Cyclohexylsalicylic acid, 3,5-dijerL-
Butylsalicylic acid, 3,5-di-α-methylbenzylsalicylic acid, 4,4'-isopropylidenediphenol,
4,4'-isopropylidene bis(2-chlorophenol), 4,4'-isopropylidene bis(2,6-dibromophenol), 4,4'-isopropylidene bis(
2,6-dichlorophenol), 4,4'-isopropylidene bis(2-methylphenol), 4,4'-isopropylidene bis(2,6-dimethimephenol), 4
．． 4'-isopropylidene bis(2-tert-butylphenol), 4.4'-5ee-butylidene diphenol, 4,4'-cyclohexylidene bisphenol, 4,4'-cyclohexylidene bis(2-methylphenol), 4jet-butylphenol, 4-
phenylphenol, 4-hydroxydiphenoxide,
α-naph-1-ol, β-naphthol, 3,5-xylenol, thymol, methyl-4-hydroxybenzoate, 4-hydroxyacetophenone, novolak-type phenolic resin, 2,2'-thiobis(4,6-dichlorophenol) ), catechol, resorcinol, hydroquinone, pyrogallol, phloroglycin, phloroglycin carboxylic acid, 4 herL-octylcatechol, 2,2'-
Methylenebis(4-chlorophenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2゜2'-dihydroxydiphenyl, ethyl P-hydroxybenzoate, propyl P-hydroxybenzoate, ρ- Butyl hydroxybenzoate, ρ-hydroxybenzoate, Q, benzyl fomarate, p-hydroxybenzoate-p-chlorobenzyl, P-hydroxybenzoate-0-chlorobenzyl, P-hydroxybenzoate-P-methylbenzyl, P -n-octyl hydroxybenzoate, benzoic acid,
Zinc salicylate, l-hydroxy-2-naphthoic acid, 2
-hydroxy-6-naphthoic acid, 2-hydroxy-6-
Zinc naphthoate, 4-hydroxydiphenylsulfone,
4-Hydroxy-4'-chlorodiphenyl sulfone, bis(4-hydroxyphenyl) sulfide, 2-hydroxy-P-)-ruylic acid, 3,5-di-t, ert, -
Zinc butylsalicylate, 3,5-cylert, -tinbutylsalicylate, tartaric acid, oxalic acid, maleic acid, citric acid, succinic acid, stearic acid, 4-hydroxyphthalic acid, boric acid, etc.

In the present invention, the ratio of the leuco dye and color developer used in the thermosensitive coloring layer is 0.1 to 10 parts by weight, preferably 1 to 4 parts by weight, per 1 part by weight of the leuco dye. It is.

In the present invention, in order to bind and support the leuco dye and color developer on the support, various commonly used binders can be used as appropriate, such as polyvinyl alcohol, starch and its derivatives, methoxycellulose, hydroxyl, etc. Cellulose derivatives such as ethyl cellulose, carboxymethyl cellulose, methyl cellulose, and ethyl cellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylic amide/acrylic ester copolymer, acrylic amide/acrylic ester/methacrylic acid ternary copolymer, styrene/ Maleic anhydride copolymer alkali salt, isobutylene/maleic anhydride copolymer alkali salt,
In addition to water-soluble polymers such as polyacrylamide, sodium alginate, gelatin, and casein, polyvinyl acetate, polyurethane, styrene/butadiene copolymer, polyacrylic acid, polyacrylic ester, vinyl chloride/vinyl acetate copolymer, and Latex such as butyl methacrylate, ethylene/vinyl acetate copolymer, styrene/butadiene/acrylic copolymer, etc. can be used.

In addition, 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 lubricant), etc. can be used in combination. In this case, fillers include, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, and surface-treated inorganic fine powders such as calcium and silica. , urea-formalin resin, styrene/methacrylic acid copolymer, polystyrene resin, and other organic fine powders. Examples of thermofusible substances include higher fatty acids or their esters, amides, or metal salts. In addition, various waxes, condensates of aromatic carboxylic acids and amines, benzoic acid phenyl esters, higher linear glycols, dialkyl 3,4-epoxy-hexahydrophthalates, higher ketones, and other thermofusible organics. Examples include compounds having a melting point of about 50 to 200°C.

〔Example〕

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-(N-methyl-3-cyclohexyl)amino-6-
Methyl-7-anirite fluorane 20 parts 10% polyvinyl alcohol aqueous solution 161I water
64゛゛[
Solution B] Benzyl p-hydroxybenzoate 10 parts Calcium carbonate 10I 110% polyvinyl alcohol aqueous solution 161/water
54/
/ Each of the above mixtures was mixed in a sander blinder 2 times.
The mixture was pulverized and dispersed for ~4 hours to prepare liquids A and B.

Next, this liquid A and liquid 8 were mixed and stirred so that the weight ratio was A:B=1:4 to obtain a heat-sensitive coating liquid.

Further, a mixture consisting of the following formulation was dispersed using a sand mill to obtain a protective layer coating solution.

Silica 5.0 parts 10
% polyvinyl alcohol aqueous solution 50.0//zinc stearate 5,071 water
39.
0 partsNext, a back coat liquid consisting of the following formulation was prepared.

■Liquid: Styrenic polymer containing aliphatic quaternary ammonium group' 10 parts by weight Ethylenebisoleic acid amide 5 parts by weight (melting point 118°C) Zinc stearate 5 parts by weight Water
80 parts by weight East Trade name: Chemistat 6300, manufactured by Sanyo Chemical Industries, Ltd. ■Liquid: Prepared by replacing ethylene bisoleic acid amide in liquid ■ with N-stearyl oleic acid amide (melting point 67°C).

Solution (2): Prepared by changing the ethylenebisoleic acid amide in the liquid (2) to N-oleyl oleic acid amide.

■Liquid: Only ethylene bisoleic acid amide was removed from ■Liquid.

(2) Solution: Only the styrene polymer containing an aliphatic quaternary ammonium group was removed from the (2) solution.

Example 1 The above-mentioned undercoat solution (2) was applied to 50 g/r& of commercially available high-quality paper so that the dry adhesion amount was 1.0 g/m, and then dried. Further, the heat-sensitive coloring layer coating solution was applied on top of the coating solution at 3.0 g/m.
The protective layer was coated and dried at a concentration of 3.0 g/rrr, and then laminated to obtain a sample.

Example 2 A sample was obtained in the same manner as in Example 1 except that the undercoat liquid in Example 1 was replaced with liquid (2).

Comparative Example 1 A sample was obtained in the same manner as in Example 1 except that the undercoat liquid in Example 1 was replaced with liquid (2).

Comparative Example 2 A sample was obtained in the same manner as in Example 1 except that the undercoat liquid in Example 1 was replaced with liquid (2).

Comparative Example 3 A sample was obtained in the same manner as in Example 1 except that the undercoat liquid in Example 1 was replaced with liquid (2).

Next, the sample was calendered using a super calender to give a gloss level of 15 to 20% to obtain a test sample.

Regarding the above sample, its surface resistance was measured, the coefficient of static friction was measured under various conditions, and a FAX paper jam test was conducted. The results are shown in Table ■.

The surface resistance of the jujube was measured using a resistance meter manufactured by YHP.

■The coefficient of static friction was measured using a Masatsu angle meter manufactured by Kaise Riki.

Table ■ 0...No practical problem It is clear that there is almost no jamming or multilayer feeding, and that the automatic paper feeding performance is very good.

Further, even when the heat-sensitive recording material of the present invention was printed at high speed using a Ricoh facsimile machine (nIFAX 120), the high-speed running was not hindered and a clear black image with high density was provided.

Claims (2)

[Claims] (1) In a heat-sensitive recording material in which a heat-sensitive recording layer is provided on a support, an underlayer consisting of a styrene polymer containing an aliphatic quaternary ammonium group and a wax having a melting point of 60°C or higher is provided below the heat-sensitive recording layer. A heat-sensitive recording material characterized by being provided with a coating layer. (2) The ratio of the styrene polymer containing an aliphatic quaternary ammonium group to the wax with a melting point of 60°C or higher is 1:5 to 1:5.
5:1 heat-sensitive recording material according to claim 1.