JPS62117787A - Thermal recording material - Google Patents

Abstract

PURPOSE:To provide a thermal recording material enhanced in thermal sensitivity, by forming an undercoat layer by laminating a first undercoat layer containing hollow fine particles and a second undercoat layer containing an org. filler and/or an inorg. filler. CONSTITUTION:In a thermal recording material wherein an undercoat layer and a thermal color forming layer are successively laminated to a support, the undercoat layer is formed by laminating a first undercoat layer containing hollow fine particles and a second undercoat layer containing an org. filler and/or an inorg. filler. As the hollow fine particles contained in the first undercoat layer, for example, there are hollow fine particles formed of various materials such as glass ceramics and plastics. The pref. particle size of the hollow fine particles used in the first undercoat layer is usually 50mum or less: corpuscle is more preferable. As the filler used in the second undercoat layer, for example, not only the inorg. filler such as calcium carbonate, silica or talc but also the org. fillter such as a urea-formalin resin can be designated.

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]

Conventionally, various heat-sensitive recording materials have been known in which a heat-sensitive coloring layer containing a leuco dye and a color developer is provided on a support. It is widely used in the field of printers such as calculators, recorders for medical measurement, facsimiles, automatic ticket vending machines, thermal labels, thermal copying, etc. However, one of the drawbacks of recording methods using such heat-sensitive recording materials is that the recording speed is slower than that of electrostatic recording methods. Until now, various methods have been proposed to improve the recording speed, that is, to improve the thermal responsiveness of the thermosensitive coloring layer, such as incorporating a heat sensitizer into the thermosensitive coloring layer. , still not satisfactory.

〔the purpose〕

An object of the present invention is to provide a heat-sensitive recording material with increased heat sensitivity by providing a special underlayer.

〔composition〕

According to the present invention, in the heat-sensitive recording material formed by laminating an undercoat layer and a heat-sensitive coloring layer on a support in that order, the undercoat includes a first undercoat layer containing hollow particles, an organic filler and/or Alternatively, there is provided a heat-sensitive recording material characterized in that it is formed by laminating a second undercoat layer containing an inorganic filler.

In the present invention, various conventionally known hollow particles are used as the hollow particles contained in the first undercoat layer, such as glass, ceramics,
There are hollow bodies made of various materials such as plastic. When using the above-mentioned hollow body fine particles in the present invention, they may be already formed into hollow bodies before being coated on the support, or they may not be made hollow at the time of coating, but may be heated during the coating process. Alternatively, the material may be made into a hollow body by the following means.

Conventionally, many techniques are known in which a layer containing various fillers is independently provided as an undercoat layer.
Furthermore, techniques have already been proposed in which an undercoat layer containing hollow particles is provided alone, or an undercoat layer formed by laminating a plurality of layers having different compositions is provided. However, when only an undercoat layer containing hollow particles is provided, the heat insulation property can be improved, but since the particle size of the hollow particles is relatively large, the smoothness can be improved, Regarding improvement in properties, no effect can be obtained when hollow particles are used. Therefore, the objective of the present invention to improve thermal sensitivity is to provide an undercoat layer in which a first undercoat layer containing hollow particles and a second undercoat layer containing an organic filler and/or an inorganic filler are laminated. achieved for the first time.

The particle size of the hollow fine particles used in the first undercoat layer of the present invention is usually 50 μm or less, and the finer the particles, the more desirable. Fillers used in the second undercoat layer include conventionally known general fillers such as calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, magnesium hydroxide, barium sulfate, clay, talc, and other inorganic fillers. , urea-formalin resin, styrene-methacrylic acid copolymer, polystyrene resin, and other organic fillers. Furthermore, the first undercoat layer may contain, in addition to the hollow particles, the above-mentioned general fillers used in the second undercoat layer.

In order to form the undercoat layer of the present invention, generally known water-soluble polymers and aqueous emulsions can be appropriately used as binders, such as polyvinyl alcohol, starch and its derivatives, methoxy cellulose,
Cellulose derivatives such as hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose.

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, poly Acrylamide, sodium alginate, gelatin,
In addition to water-soluble polymers such as casein, polyvinyl acetate, polyurethane, styrene/butadiene copolymer, polyacrylic acid, polyacrylic acid ester, vinyl chloride/vinyl acetate copolymer, polybutyl methacrylate, ethylene/vinegar vinyl Latexes such as copolymers, styrene/butadiene/acrylic copolymers, etc. can be used.

The heat-sensitive color forming layer of the present invention is mainly composed of a leuco dye and a color developer, and the leuco dyes can be applied alone or in a mixture of two or more kinds. Any dye that is used in recording materials may be used, and leuco compounds of dyes such as triphenylmethane, fluoran, phenothiazine, auramine, and spiropyran dyes are preferably used. Specific examples of such leuco dyes include those shown below.

3.3-bis(P-dimethylaminophenyl)-phthalide, 3.3-bis(ρ-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone), 3.3-bis(P- dimethylaminophenyl)-6-diethylaminophthalide, 3,3-bis(P-dimethylaminophenylchlorphthalide, 3,3-bis(P-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6- Chlorfluorane 3-
Dimethylamino-5,7-dimethylfluoran 3-diethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran, 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'-trifluoromethylphenylamino)-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-(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-(N,N-diethylamino)-5-methyl-7-(
N.

N-dibenzylamino) fluorane, benzoylleucomethylene blue, 6'-chloro-8'-me-1-xy-benzoindolino-
Pyrillospirane, 6'-bromo-3'-methoxy-benzoindolino-virillospirane.

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)fluoran, 3-diethylamino-7-(o-methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-py peridinofluorane, 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.

In addition, as the color developer used in the present invention, various electron-accepting substances that react with the leuco dye mentioned above and develop color when heated are used, and specific examples thereof include phenol as shown below. Examples include acidic substances, organic or inorganic acidic substances, and salts thereof.

gallic acid, salicylic acid, 3-isopropylsalicylic acid,
3-cyclohexylsalicylic acid, 3,5-jerL
-butylsalicylic acid, 3,5-di-α-methylbenzylsalicylic acid, 4,4'-isopropylidene diphenol, 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-dimethylphenol),
4.4'-isopropylidene bis(2-tart-butylphenol), 4.4'-5ec-butylidene diphenol, 4,4'-cyclohexylidene bisphenol, 4.4'-cyclohexylidene bis(2-methyl phenol), 4-tert-butylphenol, 4
-Phenylphenol, 4-hydroxydiphenoxide, α-naphthol, β-naphthol, 3,5-xylenol, thymol, methyl-4-hydroxybenzoate, 4-hydroxyacetophenone, novolac type phenolic resin, 2,2'-thiobis( 4,6-dichlorophenol), catechol, resorcinol, hydroquinone, pyrogallol, prologlycine, phloroglycin carboxylic acid, 4-hart, -octylcatechol, 2,2'
-methylenebis(4-chlorophenol), 2,2'-
Methylenebis(4-methyl-6-tert-butylphenol), 2゜2'-dihydroxydiphenyl, ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate, butyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, p -p-chlorobenzyl hydroxybenzoate, 0-chlorobenzyl p-hydroxybenzoate, p-methylbenzyl p-hydroxybenzoate,
n-octyl P-hydroxybenzoate, benzoic acid, zinc salicylate, 1-hydroxy-2-naphthoic acid, 2-
Hydroxy-6-naphthoic acid, zinc 2-hydroxy-6-naphthoic acid, 4-hydroxydiphenylsulfone, 4
-Hydroxy-4'-chlorodiphenyl sulfone, bis(4-hydroxyphenyl) sulfide, 2-hydroxy-p-toluic acid, 3,5-di-butyltin salicylate, tartaric acid, oxalic acid, maleic acid, citric acid, Succinic acid, stearic acid, 4-hydroxyphthalic acid, boric acid, etc.

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, acryl amide/acrylic ester/methacrylic acid ternary copolymer, styrene/ Maleic anhydride copolymer alkali salt, inbutylene/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 acid ester, vinyl chloride/vinyl acetate copolymer, Latex such as polybutyl 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,
A thermofusible substance (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, phenylester benzoate, higher linear glycols, dialkyl 3,4-epoxy-hexahydrophthalates, higher ketones,
Examples include other thermofusible organic compounds having a melting point of about 50 to 200°C.

Generally known methods can be used to obtain the heat-sensitive recording material of the present invention. That is, a leuco dye, a color developer, a binder, and other additives may be used alone or in a mixture other than the leuco dye, and a protective colloid substance such as polyvinyl alcohol, a surfactant, etc. may be added to the ball mill, attritor, etc.
After dispersing with a dispersing machine such as a sand mill, a heat-sensitive coloring layer coating solution is prepared according to the recipe, coated on the undercoat layer, dried, and then calendered to obtain the heat-sensitive recording sheet of the present invention.

Note that in the heat-sensitive recording material of the present invention, a protective layer may be provided on the heat-sensitive coloring layer for the purpose of improving the matching property with a thermal pen or a thermal head, etc., and further enhancing the storage stability of recorded images. In this case, the above-mentioned filler binder, surfactant, thermofusible substance (or lubricant), etc. can also be used as components constituting the protective layer.

〔effect〕

In the heat-sensitive recording material of the present invention, by having a structure in which a first undercoat layer containing hollow particles and a second undercoat layer containing a general filler are laminated,
It is a heat-sensitive recording material that can form an undercoat layer that has higher heat insulation properties and smoothness than ever before, and has extremely high heat sensitivity.

〔Example〕

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

Examples 1-2 A mixture consisting of the following components was stirred and dispersed in a ball mill (
Solutions A) to (D) were prepared.

[A liquid]

Foamed hollow particles of borosilicate glass-sodium salt 20 parts 40%
Styrene/butadiene copolymer latex emulsion 40 parts water
4
0 parts [Liquid B] Plastic foam hollow particles 20 parts 40%
Styrene/butadiene copolymer latex emulsion 40 parts water
4
0 parts [Liquid C] Modified polystyrene filler 30 parts 40%
Styrene/butadiene copolymer latex emulsion 15 parts water

55 parts [Liquid D] Silica 30 parts 40
% styrene/butadiene copolymer latex emulsion 15 parts water
5
A mixture consisting of 5 parts of the following components was dispersed using a sand glider for 2 hours to prepare solutions [E] to [F].

[E liquid]

3-(N-methyl-N-cyclohexyl)amino-6-
Methyl-7-anirite fluorane 20 parts 10% polyvinyl alcohol aqueous solution 20 parts water
60 copies [F
Liquid] 1.7-di(4-hydroxyphenylthio)-3,5-
Dioxahebutane 10 parts Calcium carbonate 15 parts lO% polyvinyl alcohol aqueous solution 25 parts Water
50 copies above [A]
~ (F) After adjusting the liquid, [E] and the CF'l liquid were mixed and stirred so that the weight ratio was 6, and the thermosensitive coloring layer coating liquid [G] was prepared.
) was obtained. Next, each adjustment solution was applied to a 52 g/m high-quality paper in the composition shown in Table 1 below, and then the surface was calendered so that the Beck smoothness was 600 to 100 seconds. I got ~2.

Table 1 Comparative Examples 1 to 3 A mixture consisting of the following components was stirred and dispersed in a ball mill to prepare [11] liquid.

[H liquid]

Calcium carbonate 30 parts 40%
Styrene/butadiene copolymer latex emulsion 15 parts water
5
Comparative Examples 1 to 3 were obtained using 5 parts of the above-mentioned adjustment solution in the same manner as in the Examples using the compositions shown in Table 2 below.

Table 2 A thermal sensitivity test was conducted on the above five types of thermal recording materials. The test was conducted using a thermal printing test device with a thin film head manufactured by Matsushita Electronics Components with a head power of 0.45 V/d.
oL, l line recording time 20m5ec, scanning line density 8
The pulse width is 0.8 under the condition of X 3.85 doj/mm.
．． Printing was performed at a speed of 1.0.1.2.1.4111 sec, and the print density was measured using a Macbeth densitometer RD-914. The results are shown in Table 3.

Table 3 As can be seen from the results in Table 3, the heat-sensitive recording material of the present invention has high heat sensitivity.

Claims (1)

[Claims] (1) A heat-sensitive recording material comprising an undercoat layer and a heat-sensitive coloring layer laminated in this order on a support, in which the undercoat layer includes a first undercoat layer containing hollow particles, an organic filler and/or Alternatively, a heat-sensitive recording material characterized in that it is formed by laminating a second undercoat layer containing an inorganic filler.