JPH04219278A - 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]

0001

[Industrial Application Field] The present invention relates to a heat-sensitive recording material.
More specifically, the present invention relates to a heat-sensitive recording material that utilizes a color-developing reaction between a leuco dye that is colorless or slightly light-colored at room temperature and a color developer for the leuco dye.

0002

[Prior Art] Recently, various recording materials have been researched and developed in the field of information recording and put into practical use in response to social demands such as diversification and increase in information, resource conservation, and pollution-free environment. Among them, heat-sensitive recording materials are characterized by (1) the ability to record a colored image simply by heating, eliminating the need for a complicated development process, and (2) the ability to be manufactured using relatively simple and compact equipment; (3) Paper is often used as a support, and in this case, not only is the support cost low, but the feel of the resulting recorded material is also low. Because of its advantages such as being similar to plain paper, it is widely used in the fields of computer output, printers such as calculators, recorders for medical measurement, low and high speed facsimiles, automatic ticket vending machines, thermal copying, etc. .

The above-mentioned heat-sensitive recording material is produced by coating a support such as ordinary paper, synthetic paper, or synthetic resin film with a heat-sensitive coloring layer liquid containing a coloring component capable of causing a coloring reaction when heated and drying the layer. A colored image is recorded on the heat-sensitive recording material thus obtained by heating it with a thermal pen or a thermal head. Conventional examples of such heat-sensitive recording materials include, for example, the heat-sensitive recording materials disclosed in Japanese Patent Publication No. 43-4160 or Japanese Patent Publication No. 45-14039; Responsiveness was low, and sufficient color density could not be obtained during high-speed recording.

In addition, as the thermal response becomes faster, new problems such as adhesion of residue and sticking occur. -22794 has a BET
Techniques have been disclosed that focus on inorganic fillers, such as using amorphous silica with a small specific surface area and a particle size of 4 μm or less. In addition, the pore radius as an undercoat is 0.2μ.
JP-A No. 62-240580 discloses that it is possible to increase the temperature to more than characteristics have changed and satisfactory results have not been obtained.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material which has improved the above-mentioned conventional drawbacks, that is, it is free from adhesion of residue and sticking during heat recording and has excellent dynamic color development. The purpose of the present invention is to provide heat-sensitive recording materials.

[0006]

[Means for Solving the Problems] According to the present invention, in a heat-sensitive recording material in which a coloring layer containing a leuco dye and a color developer as main components is provided on a support, particles having a particle size of 5 μm or less are used as a filler. Provided is a heat-sensitive recording material characterized in that it contains 90 wt % or more of a material having a pore distribution curve peak of 0.2 μm or more.

[0007] In the present invention, the pore distribution refers to the pore distribution in a filler measured by a mercury intrusion type porometer, and it is important that the pores are the pores of the filler used.

[0008] Conventionally, improvements in matching properties, especially in preventing adhesion of residue, have been achieved by using fillers with large oil absorption, and fillers with a BET specific surface area of 100 n2/g or less have been preferred because of their low fogging. However, it was found that the occurrence of residue adhesion and sticking could not be prevented even if a filler with high oil absorption was used, and as a result of intensive research, the present invention was arrived at.

That is, according to the present invention, the size of the pores in the filler and the size of the heat-melted color developer and sensitizer affect the adhesion of scum, and even if the oil absorption is large, the pore size If the pores are too small or the amount of thermal melting is too large for the pores, it may cause residue to adhere during thermal printing.
It was found that sticking occurred. It has also been found that the quality can be further improved by setting the average particle size of the color developer and sensitizer to 2 μm or less.

[0010] The filler used in the present invention has a particle size of 5 μm.
m or less is 90wt% or more, preferably 4μm or less is 95w
A material with a pore distribution peak of 0.2 μm or more at t% or more is used. Specific examples thereof are shown in Table 1 below, but of course the invention is not limited to these examples.

[0011] In the present invention, it is also possible to use other known fillers in combination with the filler, such as calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, water, etc. Examples include fine inorganic powders such as zinc oxide, barium sulfate, clay, talc, and surface-treated calcium and silica, as well as fine organic powders such as urea-formalin resin, styrene/methacrylic acid copolymer, and polystyrene resin. be able to.

[0012] Here, the filler amount is 50 to 500 wt%, preferably 100 to 30 wt% based on the entire hot melt.
0 wt% is an appropriate amount.

[0013]

[Table 1]
*: Oil absorption was determined according to the Ogura method.

As the leuco dye used in the present invention, leuco dyes that are generally known for this type of leuco recording material are used, such as triphenylmethane, fluoran, phenothiazine, auramine, and spiropyran. Leuco compounds of such dyes are preferably used. Specific examples of such leuco dyes include:
For example, the following can be mentioned. 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-diethylaminophthalide, 3,3-bis(p-dimethylaminophenyl)-6-chlorphthalide , 3,3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlorofluoran,
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-ethylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2-{N-(3'-trifluoromethylphenyl)amino}-6-diethylaminofluorane, 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)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-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)fluoran, 3-pyrrolidino-7-trifluoromethylanilinofluoran, 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-(o-methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl-7-(α-phenylethylamino)fluoran, 3- Diethylamino-7-piperidinofluorane, 2-
Chloro-3-(N-methyltoluidino)-7-(pn
-butylanilino)fluoran, 3-(N-benzyl-N-cyclohexylamino)-5
, 6-benzo-7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino-4', 5'-benzofluorane, 3-diethylamino-6-methyl-7 −(2′,4′−
dimethylanilino) fluorane, etc. 3-(p-dimethylaminophenyl)-3-{1,1-
Bis(p-dimethylaminophenyl)ethylene-2-yl}phthalide, 3-(p-dimethylaminophenyl)-
3-{1,1-bis(p-dimethylaminophenyl)ethylene-2-yl}-6-dimethylaminophthalide, 3-(p-dimethylaminophenyl)-3-(1-p-
dimethylaminophenyl-1-phenylethylene-2-
yl)phthalide, 3-(p-dimethylaminophenyl)
-3-(1-p-dimethylaminophenyl-1-p-chlorophenylethylene-2-yl)-6-dimethylaminophthalide, 3-(4'-dimethylamino-2'-methoxy)-3-
(1″-p-dimethylaminophenyl-1″-p-chlorophenyl-1″,3″-butadien-4″-yl)benzophthalide, 3-(4′-dimethylamino-2′-benzyloxy)-3- (1″-p-dimethylaminophenyl-1″-phenyl-1″,3″-butadiene-4″
-yl)benzophthalide, 3-dimethylamino-6-dimethylamino-fluorene-9-spiro-3'-(6'
-dimethylamino)phthalide, 3,3-bis{2-(p
-dimethylaminophenyl)-2-(p-methoxyphenyl)ethenyl}-4,5,6,7-tetrachlorophthalide, 3-bis{1,1-bis(4-pyrrolidinophenyl)ethylene-2- yl}-5,6-dichloro-4,7-dibromophthalide, bis(p-dimethylaminostyryl)-
1-naphthylenesulfonylmethane, etc.

In the present invention, various electron-accepting compounds such as phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids and metal salts thereof, etc. can be used in combination as the color developer. Examples include the following: Bentonite, zeolite, acid clay, activated clay, silica gel, phenolic resin, 4,4'-isopropylidene diphenol, 4,4'-
Isopropylidene bis(o-methylphenol), 4,
4'-Secondary butylidene bisphenol 4,4'
-isopropylidene bis(o-tert-butylphenol), 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-methyl)phenol, 1,1,3-tris(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-methyl)phenol, 4,4'-diphenolsulfone, 4,2'-diphenolsulfone, 4-isopropoxy-4' -hydroxydiphenylsulfone, 4-benzyloxy-4'-hydroxydiphenylsulfone, 4,4'-diphenolsulfoxide, isopropyl P-hydroxybenzoate, benzyl P-hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate , octyl gallate, 1,7-bis(4-hydroxyphenylthio)-3,5
-dioxaheptane, 1,5-bis(4-hydroxyphenylthio)-3-oxapentane, 1,3-bis(4-hydroxyphenylthio)-propane, 2,2'-methylenebis(4-ethyl-6) -tert-butylphenol), 1,3-bis(4-hydroxyphenylthio)-2-hydroxypropane, N,N'-diphenylthiourea, N,N'-di(m-chlorophenyl)thiourea, salicylanilide, 5-chloro-salicylanilide, salicyl-o-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-2-naphthoic acid, metal salts of hydroxynaphthoic acid such as zinc, aluminum, calcium, etc., 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, antipyrine complex of α,α-bis(4-hydroxyphenyl)-α-methyltoluene zinc thiocyanate, tetrabromobisphenol A, Tetrabromobisphenol S, 3,4-dihydroxy-4'-methyldiphenylsulfone, 4,4'-thiobis(2-methylphenol), 4
, 4'-thiobis(2-chlorophenol), etc.

In the present invention, when a leuco dye and a color developer are bonded and supported on a support in order to obtain a heat-sensitive recording material, various conventional binders can be used as appropriate. Further, in order to obtain a pressure-sensitive recording material, when an encapsulated leuco dye is supported on a support or a coloring agent is supported on a support, various commonly used 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, polysodium acrylate, 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, casein, etc. 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 Latex such as coalescence.

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. Specific examples thereof include the following compounds. It will be done.

Fatty acids such as stearic acid and behenic acid, fatty acid amides such as stearic acid amide and palmitic acid amide, zinc stearate, aluminum stearate,
Fatty acid metal salts such as calcium stearate, zinc palmitate, zinc behenate, p-benzylbiphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, β
-naphthoic acid phenyl ester, 1-hydroxy-2-
Naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid methyl ester, diphenyl carbonate, terephthalic acid dibenzyl ester, terephthalic acid dimethyl ester, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-di Benzyloxynaphthalene, 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)ethane,
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, 1,1-diphenylethanol, 1,1 -diphenylpropanol,
p-(benzyloxy)benzyl alcohol, 1,3-
Diphenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N-octadecylcarbamoylbenzene, oxalic acid dibenzyl ester, 1,5-bis(p-methoxyphenyloxy)-
3-oxapentane, bis(4-methylbenzyl) oxalate
, bis(4-chlorobenzyl) oxalate, 1,2-bis(3
, 4-dimethylphenyl)ethane, etc.

[0020] In addition, in the present invention, if necessary, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as
Fillers, surfactants, lubricants, pressure coloring inhibitors, 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. Examples of lubricants include higher fatty acids and their metal salts, higher fatty acid amides, higher fatty acid esters, and animal-based , various vegetable, mineral, or petroleum waxes. Further, regarding the layer structure, it may be a single layer or a multilayer, and an over layer, an under layer, and a back layer may be provided as necessary.

[0021]

[Effects] The heat-sensitive recording material of the present invention is free from adhesion of residue and sticking, has excellent printing quality, and is highly practical.

[0022]

EXAMPLES 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 weight.

Example 1 Calcined kaolin (Kaocal)

100 parts Sodium hexametaphosphate

1 part 47.5% styrene
butadiene latex
60 parts (Mitsui Toatsu Polylac 750) 30% paraffin wax (Chukyo Yushi Co., Ltd., Hydrin D-338) 45 parts Water


After preparing and stirring 300 parts of the undercoat liquid having the above composition, it was coated on high-quality paper with a basis weight of 47 g/m<2> to a dry weight of 5 g/m<2> and dried to obtain an undercoat paper. Next, a mixture of the following composition was ground for 4 to 8 hours using a sand mill for heat-sensitive liquids, respectively [A] liquid and [
B] Solution was prepared.

[A] Liquid 3-dibutylamino-6-methyl-7-anilinofluorane 20 parts 10% polyvinyl alcohol
20 copies
water

60 parts [B] Liquid Bisphenol A

20 parts 1,2-bis(3,4-dimethylphenyl)ethane
40 parts 10% polyvinyl alcohol

60 parts water


120 parts Here, the average particle size of liquid [A] and liquid [B] is 1
．． It was 5 μm. Next, the heat-sensitive coating liquid was prepared and thoroughly stirred. [A] Liquid

100 parts [B] Liquid

2
00 parts Calcium carbonate (Brillia manufactured by Shiraishi Industries)
nt15) 100 copies 30
% acrylic ester

60 parts water

250 parts of this heat-sensitive liquid was coated on undercoat paper so that the dry coating amount was 4.5 g/m<2 >and dried, followed by calendering to obtain a heat-sensitive recording material of the present invention.

Example 2 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 1 except that KK-14 was used instead of Kaocal in the undercoat liquid.

Comparative Example 1 A comparative heat-sensitive recording material was obtained in the same manner as in Example 1 except that Ultra White 90 was used instead of Kaocal in the undercoat liquid.

Comparative Example 2 A comparative thermal recording paper was obtained in the same manner as in Example 1 except that Thyroid 404 was used instead of Kaocal as the undercoat liquid. The peak of the pore distribution of this undercoated paper was 0.27 μm.

Example 3 A thermal recording paper of the present invention was obtained in the same manner as in Comparative Example 1, except that KK-13 was used instead of Brilliant 15 in the thermal coating liquid.

Example 4 In Comparative Example 1, the heat-sensitive coating liquid Brilliant 1
A thermosensitive recording paper of the present invention was obtained in the same manner except that Mizukasil P-832 was used instead of Mizukashiru P-832.

The following quality evaluations were 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 2. (1) Dynamic coloring property: Head power 0.45 using a thermal printing experimental device with a thin film head manufactured by Matsushita Electronic Components Co., Ltd.
W/dot, 1 line recording time 20ms/l, scanning line density 8 x 3.85 dots/mm, pulse width 0.2
, 0.4, 0.6, 0.8, 1.0 msec,
The print density was measured using a Macbeth densitometer RD-114. (2) Debris adhesion...The above printing device has a pulse width of 1.
A length of 1 m was printed at 0 msec, and the state of adhesion of residue after printing was visually determined. (3) Sticking property: Continuous printing of 10 cm with a pulse width of 1.0 msec using the above printing device, 0.5 sec
The c-stop pattern was repeated four times, and the head adhesion state that occurred after the stop was visually judged.

[0031]

[Table 2] [Scrap adhesion] ○: Almost absent, △: Slightly present, ×: Obviously present [Sticking] ○: Almost absent, △:
Slight white streaks, ×: White streaks

As is clear from Table 2, the heat-sensitive recording material of the present invention has excellent dynamic color development, dregs adhesion, and sticking, and is highly practical compared to the comparative heat-sensitive recording paper.

Claims (2)

[Claims] Claim 1: A heat-sensitive recording material in which a color-forming layer containing a leuco dye and a color developer as main components is provided on a support, in which 90 wt% or more of filler has a particle size of 5 μm or less, and the pore size is A heat-sensitive recording material characterized by containing a material whose distribution curve has a peak of 0.2 μm or more. 2. The heat-sensitive recording material according to claim 1, wherein the color developer and sensitizer forming the heat-sensitive coloring layer have an average particle diameter of 2 μm or less.