JPS60259493A - Thermal recording material - Google Patents

Abstract

PURPOSE:To enhance the tonal recordability and thermally color-forming property of a thermal recording material by using two or more kinds of micro capsules whose walls have different glass transition points. CONSTITUTION:In a thermal recording material having a micro capsule whose core contains an organic solvent and at least one of components capable of producing color forming reactions and a supporter whose one face contains an another component capable of forming a color upon reaction of the component cqpable of producing color forming reactions, two or more kinds of micro capsules whose walls have different glass transition points are used as the micro cupsule. Th use of the two or maor kinds of the micro capsules having different glass transition points makes tonal reproductivity of pictures better since print densities to applied energies are different due to the different glass transition points of the capsule walls, although the walls are not almost fused even when heated by removing out the core substance of the micro capsule liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-sensitive recording material, and in particular to a new heat-sensitive paper that has excellent thermal responsiveness and is capable of reproducing halftones.

"Prior art" When the body is paper, the paper quality is similar to ordinary paper (3) It is easy to handle (4) The color density is high (5) The recording device is simple and inexpensive . (6) Because it has advantages such as no noise during recording, it has become rapidly popular in the field of facsimiles and printers in recent years. As a heat-sensitive recording material for this,
Leuco color-forming heat-sensitive recording materials are mainly used, which have excellent color development density and color development speed.

In general, text recording is the most common type of thermal recording, but
In recent years, there has been an increasing demand for recording images with gradation, such as hard copies of television images. As a method of expressing gradation,
There are two methods: one is to keep the recording density constant and change the recording area, and the other is to keep the recording area constant and change the recording density.However, the former lowers the resolution and there is a limit to the expression of intermediate tones, so the latter is preferable. is excellent. However, while the former method is suitable for conventional thermal paper, the latter method is not so suitable. This is because the latter method requires printing at an intermediate degree as thermal paper. In other words, is there a certain degree of smoothness in response to changes in applied energy? (the rate of change is not too large).

However, conventional leuco color-forming thermal recording paper is made by finely dispersing leuco dye and phenolic color developer into micron-order sizes, mixing them, and applying the mixture to a paper support, which is then heated with a thermal head. In this case, the color-forming components melt and mix with each other to develop color, but it is not easy to create differences in temperature characteristics between particles or between coated layer parts.

``Problems to be solved by the invention'' Conventional thermal paper has problems with applied energy (particularly in low-density areas).
The rate of change in color density with respect to changes in heat (heat amount) is large, and stable and gradation recording performance is poor.

``Object of the Invention'' Therefore, the first object of the present invention is to provide a recording material that is excellent in smooth gradation recording properties and has high thermochromic properties.

A second object of the present invention is to provide a recording material that has excellent manufacturing suitability and excellent image storage stability.

"Means for Solving the Problems" As a result of intensive research, the present inventors have found that a microcapsule containing at least one component that causes a color reaction and an organic solvent in the core, a component that causes a color reaction, and one, : j As a core microcapsule in a heat-sensitive material having the other component that reacts with the other component on the same side of the support,
This was achieved using a heat-sensitive recording material characterized by using two or more types of microcapsules whose walls have different glass transition points.

"Operation" The microcapsules of the present invention are destroyed by heat or pressure, as used in conventional recording materials, to bring the reactive substances contained in the core of the microcapsules into contact with the reactive substances outside the microcapsules. Rather than causing a color reaction by heating the core of the microcapsule and the reactive substance present on the outside, it permeates through the microcapsule wall and causes a reaction. Until now, it has been known that when microcapsule walls are formed by a polymerization method, they do not become completely impermeable membranes but are permeable. This permeability of the microcapsule wall is known to be a phenomenon in which low-molecular substances gradually permeate over a long period of time.
The phenomenon of instantaneous transmission due to heating as in the present invention was not known.

Therefore, the microcapsule walls of the present invention do not necessarily need to be melted by heat.

Even when the core substance of the microcapsule liquid used in the method of the present invention is removed and heated, the apparent clay walls hardly melt. However, if the glass transition points of the microcapsule walls are different, the printing density with respect to the applied energy will be different, so gradation reproducibility can be improved by using two or more types of microcapsules with different glass transition points.

The present invention will be explained in more detail.

The organic solvent used in the present invention preferably has a low boiling point and has a lZ of 0 or more since there is evaporation loss during raw storage. , alkylated biphenyl, alkylated terphenyl, chlorinated paraffin, alkylated naphthalene, diarylethane, etc. are used.

Specific examples include tricresyl phosphate, trioctyl phosphate, octyldiphenyl phosphate, tricyclohexyl phosphate, dibutyl phthalate, dioctyl phthalate, dilaurate phthalate, dicyclohexyl phthalate, phthyl oleate, diethylene glycol dibenzoate, and sebacic acid. Dioctyl, dibutyl sepacate, dioctyl adipate, trioctyl trimellitate, cetyltriethyl citrate, octyl maleate, dibutyl maleate, isopropylbiphenyl, isoamyl biphenyl, chlorinated nomirafine, diisopropylnaphthalene, /
, /'-ditolylethane &'l''-ditertiary aminophenol%N,N-dibutyl-cobutoxy-y-tertiary octylaniline, and the like.

Among the synthetic resins, polyurea, polyurethane, polyester, and polyamide can be used as capsule wall materials.

Particularly good results are obtained when using urea-formalin resins or mixtures thereof.

Capsule walls can be formed by encapsulation by polymerizing actant from inside oil droplets, or by precipitation of polymers, which result in dense walls and excellent storage stability.

Capsule size and wall thickness can be easily controlled and preferred capsules can be obtained.

This method and specific examples of compounds are described in U.S. Patent J.
, No. 724.1044, J, 796, No. 7t.

For example, when polyurethane is used as a capsule wall material, polyvalent incyanate and a second substance (e.g. polyol) that reacts with it to form the capsule wall are mixed into the oily liquid to be encapsulated, emulsified and dispersed in water, and then heated to As the oil rises, a polymer formation reaction occurs at the oil droplet interface, forming the capsule wall. At this time, an auxiliary solvent with a low boiling point and strong dissolving power can be used in the oil droplet liquid.

In this case, regarding the polyisocyanate to be used and the polyol and polyamine to be reacted with it, US Pat.
Te No. 1% Kosho at-g.

3μ7 No. 11, same Dataco Hiro No. 11, JP-A-Shoμt-7fQ
No. 191, disclosed in μr-r4Aott No.
You can also use them.

1. Polyvalent incyanate♂, the first wall-forming substance
And L? u, fPJ. -7,=7. I, tour oh 1. p-phenylene diisocyanate, co, t-tolylene diisocyanate, 2,4I-)lylene diisocyanate, naphthalene/-11 μm diisocyanate, diphenylmethane-l, ≠'-diisocyanate, 3.3
'-dimethoxy-μ, μ'-biphenyl diisocyanate, 3.3'-dimethyldiphenylmethane-μ, 4L
'-Diisocyanate, xylylene-71μm diinocyanate, a,a'-diphenylpronoξ diinocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-/, J-diisocyanate, butylene-7,2-diincyanate, cyclohexylene- % of diisocyanates such as /, Z-diisocyanate, cyclohexylene-11 μm diisocyanate <z, g', g"-triisocyanates such as triphenylmethane triisocyanate, toluene-λ, 4', 4-) diisocyanate, lA, u' -dimethyldiphenylmethane-2, J', j+, j'-tetrine cyanate such as tetraisocyapate, hexamethylene diisocyanate and trimethylolpropane, 2. u-tolylene diisocyanate and trimethy4-ruzorono There are isocyanate prepolymers such as adducts of ξ, adducts of xylylene diisocyanate and trimethylolpropane, and adducts of tolylene diisocyanate and hexanetriol.

The polyol, which is one of the second wall film-forming substances, is
These include aliphatic and aromatic polyhydric alcohols, hydroxy polyesters, and hydroxy polyalkylene ethers. Preferred polyols have a molecular weight that has the following groups (I), (II), (III), or (W) between 1.2 hydroxyl groups in the molecular structure! Examples include polyhydroxy compounds where θθO or less.

(I) aliphatic hydrocarbon group 1 1 (W) -0-Ar-C-Ar-0- with carbon number λ to l, where (II
), YI[), Ar in (W) represents a substituted or unsubstituted aromatic moiety, and the aliphatic hydrocarbon group in (T) is
The basic skeleton is -CnH2n-, and hydrogen groups may be substituted with other elements.

To give a specific example, as an example of (1).

Ethylene glycol &/, J--10g diol,
1Iq-butanediol% /, j-<methanediol, /, 7-hexanediol, 1.7-hebutansinol, 1.1-octanediol, propylene glycol, λ, 3-dihydroxybutane, 1.2-dihydroxybutane '1313-dihydroxyptaf, cordimethyl-/, 3-propanediol% 2. a--Z tannediol% λlj-hexanediol, 3-methyl-
/ ”, ji-hentanediol, /, g-cyclohexane dimetatool, dihydrogycyclohexane,
Diethylene glycol %'lλ, J-) dihydroxyhexane, phenylethylene glycol, /, /, 7-trimethylolpropane, hexanetriol, pentaerythritol, glycerin, etc. are used.

Examples of (I[) include condensation products of aromatic polyhydric alcohols and alkylene oxides such as /, t-di(2-hydroxyethoxy)benzene, and resorcinol dihydroxyethyl ether.

An example of (III) is % p-xylylene glycol.
m-xylylene glycol, α, α'-dihydroxy-p-diisopropylbenzene, etc. are used.

Examples of IN) include h ≠ pl-dihydroxy-diphenylmethane% co(p,l)'-dihydroxydiphenylmethyl)benzyl alcohol, hisphenol A
adducts of ethylene oxide.

・6: Examples include adducts of propylene oxide to bisphenol A. The polyol is preferably used in a proportion of hydroxyl groups of 0.02 to λ mol per mol of incyanate groups.

Polyamines that are other second wall-forming substances include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, p-phenylenediamine, m-phenylenediamine, biylazine, and comethylbiperazine. % Ko,!
Examples include -dimethylpiperazine, 2-hydroxytrimethylenediamine, diethylenetriamine, triethylenetriamine, triethylenetetramine, diethylaminopropylamine, tetraethylenepentamine, and amine adducts of Ebuki 7 compounds.

By varying the amount of polyisocyanate, polyol, or polyamine added, the wall thickness will vary, other things being equal. By varying the agitation during emulsification and dispersion, the particle size and therefore the wall thickness, other things being equal, can be varied.

Water-soluble polymers can be used when making microcapsules, but water-soluble polymers include water-soluble anionic polymers, nonionic polymers, amphoteric polymers, and cyanionic polymers include water-soluble polymers. , both natural and synthetic ones can be used, such as those having -COO, -8Oa groups, etc. Specific anionic natural polymers include gum arabic and alginic acid.
Semi-synthetic products include carboxymethyl cellulose, phthalated gelatin, sulfated starch, sulfated cellulose, and lignin sulfonic acid.

Synthetic products include maleic anhydride copolymers (including hydrolyzed ones), acrylic acid (including methacrylic acid) polymers and copolymers, and vinylbenzenesulfonic acid polymers and copolymers. , carboxy-modified polyvinyl alcohol, etc.

Examples of nonionic polymers include polyvinyl alcohol, hydroxyethyl cellulose, and methyl cellulose.

Examples of amphoteric compounds include gelatin.

These water-soluble polymers are used as a 0.0/-10 wf, % aqueous solution.

The glass transition point of the capsule wall of the present invention is the glass transition point "as a system" including the effects of couplers, basic substances, color development accelerators, and the like.

That is, the glass transition point itself inherent to the capsule wall, or the substance outside the capsule (especially the glass transition point adjusting agent), is heated and melted during thermal printing and diffuses into the capsule wall.
This is the glass transition point in an interaction state. The former method of controlling the glass transition point specific to the capsule wall is based on p
The solution is to change the type of cell wall forming agent. For polyurea, polyurethane, and mixed polyurea/urethane capsules, change the type of incyanate used.

This is particularly advantageous because the glass transition point can be changed widely by changing the type and amount of the polyol and polyamine used together.

The glass transition point in the state where the latter interaction occurs can be changed by placing a glass transition point adjusting agent outside the capsule. Particularly effective are hydroxy compounds, carbamate esters, aromatic methoxy compounds, etc. having a melting point of jO~/70°C.

This glass transition point is determined by measuring the capsule wall or the interaction substance (capsule wall/glass transition point adjusting agent outside the capsule) using Pyblon DD V-III type (manufactured by Toyo Baldwin), and determining the peak temperature of Tan δ. This means that υ is the dynamic loss modulus subtracted by the storage modulus.

The temperature at which color can be developed by the thermal paper used to cover the capsule is determined when the glass transition point of the capsule wall "as a system" is determined. The reason for this is that when the capsule wall changes from a glass state to a rubber state, substances diffuse between the inside and outside of the capsule and a coloring reaction occurs.

The capsule wall or the interaction product of the capsule wall and the heat-fusible substance to be subjected to the measurement of the glass transition point is prepared, for example, as follows.

Xylylene diisocyanate as a capsule wall component/
20 parts of trimethylolpropane (3;l adduct) was dissolved in 30 parts of ethyl acetate, coated on a polyethylene sheet, reacted in water ao, to'c, and peeled off.
-μ'C, 64! Air-dried for 1 day at %R,H, 10-2
A polyurea film with a thickness of 0 μm was obtained. This is the sample for measuring the glass transition point of the capsule wall alone. As a method for preparing an interaction product between a thermofusible substance and a capsule wall, Fi,
After immersing the above polyurea membrane in a 2096 methanol solution of p-benzyloxyphenol for 30 hours, λμ0
It was air-dried for 1 day in CA44%R,H, and used as a sample.

Preferred embodiments for use in the heat-sensitive recording material of the present invention include the following.

(1) A heat-sensitive recording material having a capsule containing a leuco dye and an organic solvent as a core substance and a color developer for developing a color from the leuco dye on the same side of a support.

+2) A heat-sensitive recording material according to (1) in which at least a part of the organic solvent is substituted with a vinyl compound and/or contains/does not contain a photopolymerization initiator.

(3) A capsule containing at least a diazo compound as a core material among a diazo compound, a coupling agent capable of coupling with the diazo compound, and a basic substance, a coupling agent, and a basic substance on the same side of the support. heat-sensitive recording material.

Examples of the leuco dye used in the heat-sensitive recording material (1) of the present invention include crystal violet lactone, 3-
Indolino-Jp-dimethylaminophenyl-6-dimethylaminophthalide, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-cyclohexylaminofluorane, 3-diethylamino-5-methyl-7- -butylfluoroy% 3-diethylamino-
6-Methyl-7-anilinofluorane, 3-diethylamine-6-methyl-7-p-butylanilinofluorane, J-(N-phenyl-N-ethyl)aminofluorane, 3-diethylamine-7- Cybenzylaminofluorane, 3-cyclohexylamino-6-chlorofluorane, 3-diethylamino-6-methyl-7-xylidinofluorane, 2-anilito-3-methyl-6-(N-ethyl-p-toluidino) Fluorane, 3-pyrrolidino-6
-Methyl-7-anilinofluorane, 3-pyrrolidino-
7-Cyclohexylaminofluorane, 3-piperidino-t-methyl-7-toluidinofluorane, 3-pyrrolidino-t-methyl-7-(p-toluidino)fluorane, 3-piperidino-6-methyl-7-ani Linofluorane, 3-N-methylcyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylami/-7-
Examples include (m-trifluoromethylaniline) fluorane, but are not limited thereto.

As the color developer for these color formers, phenol compounds, organic acids or metal salts thereof, oxybenzoic acid esters, etc. are used.

Particularly desirable are phenols and organic acids that are sparingly soluble in water and have a melting point of so' to λzo0C, preferably to'' to 000C.

Examples of phenolic compounds include μ, 4L'-isopropylidene-diphenol (bisphenol A) hP-t
ert-butylphenol, 2,4t-dinitrophenol, j, 4cm dichlorophenol, 4AI4L'-
Methylene-bis(2,t-di-tart-i-thylphenol) 1p-phenylphenol, g,u-cyclohexylidene diphenol, 2,2'-methylenebis(≠-
tert-7 tylphenol),! , 2'-methylenebis(α-phenyl-p-cresol)thiodiphenol, 4t'-thiobis(&-tert-butylm-
cresol), sulfonyldiphenol%/, 1-bis(Hiro-hydroxyphenyl)-n-totican, lA
, 4C-bis(μm hydroxyphenyl)-7-pentanoic acid ethyl ester, p-tert-butylphenol-formalin condensate, p-phenylphenol-formalin condensate, and the like.

As an organic acid or its metal salt, h j tert-
Butylsalicylic acid, 3, j-tert-butylsalicylic acid, j-α-methylbenzylsalicylic acid, 3, J-di-α-methylbenzylsalicylic acid, 3-tert-octylsalicylic acid%j-α, r-dimethyl-α-phenyl -r-phenylpropylsalicylic acid etc. and its zinc salt,
Useful are lead salts, aluminum salts, magnesium salts, and nickel salts.

Examples of oxybenzoic acid esters include ethyl p-oxybenzoate, butyl p-oxybenzoate, heptyl p-oxybenzoate, and benzyl p-oxybenzoate.

The vinylated metal material used in the heat-sensitive recording material (2) of the present invention is a compound having one or more vinyl or vinylidene groups, preferably a plurality of vinyl groups, such as an acryloyl group, a methacryloyl group, an allyl group, an unsaturated polyester group, and a vinyloxy group. Examples include compounds having an acrylamide group. The most typical examples include reaction products of polyols, polyamines, amine alcohols, etc. and unsaturated carboxylic acids, and reaction products of acrylates or methacrylates having a hydroxyl group and polyinsyanate.

For example, representative compounds include polyethylene glycol diacrylate, propylene glycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropane diacrylate, trimethylolpropane diacrylate, and pentaerythritol tetraacrylate.

□ Hexanediol diacrylate, 1. Kobuta hair diol diacrylate, tetrakis β-acryloxyethyl ethylene diamine, reaction product of epoxy resin and acrylic acid 1. These include reaction products of methacrylic acid, pentaerythritol, and acrylic acid, condensates of diethylene glycol maleate and acrylic acid, methyl methacrylate, butyl methacrylate, styrene, divinylbenzene, diarylnaphthalene, etc. A plurality of these can be used in combination depending on the purpose.

The photopolymerization initiator used in the heat-sensitive recording material (2) of the present invention includes a single compound or a combination of a plurality of organic or inorganic compounds having the ability to initiate polymerization of a vinyl compound upon irradiation with light.

These materials are already covered in detail.

For example, Kosar “Light Sensiti
veSystems” John Wiley & 5o
nsb Warashina et al. 1 Photosensitive resin, Nikkan Kogyo Shimbun, Tsunoda et al. 1
"Photosensitive resin" disclosed by the Japan Society of Printing, etc.

Specific examples of photopolymerization initiators include aromatic ketones, quinone compounds, ether compounds, and nitro compounds.

Specifically, benzoquinone, phenanthrene quinone, naphthoquinone, diisopropylphenanthrene quinone, benzoin butyl ether, benzoin, flobenzothyl ether, Michler's ketone.

Michler thioketone, tetraphenyllophine dimer 1 fluorenone, trinitrofluorenone.

Includes β-penzoyltemino-naphthalene.

These are 0.0% for vinyl compounds. /wt% to about 30wt%.

The amount of compound added per unit area is 0.0j of leuco dye.
~/, 39 preferably %O, OS~O0za2, the color developer is 0.3~lrv, preferably 0,j-4f, the organic solvent in the core material is O0/, /j f, preferably 00l-♂1, and the organic solvent can be replaced with the vinyl compound in any proportion.

The diazo compound used in the heat-sensitive material (3) of the present invention is:
It is a diazonium salt represented by the general formula A r Nz 1X-, and it is a compound that can develop a color by causing a coupling reaction with a coupling component, and can be decomposed by light. (In the formula, hAr represents a substituted or unsubstituted aromatic moiety, N2+ represents a diazonium group, and X- represents an acid anion.) Specific examples of diazonium compounds that form salts include %μ
mDiazo-7-dimethylaminobenzene.

μm diazo-l-diethylaminobenzene, μ-diazo-1-dipropylaminobenzene%≠-diazo-l-methylbenzylaminobenzene, μm diazo-1-dibenzylaminobenzene, μm Schiff / -to-ethylhydroxyethylaminobenzene , 4A-diazo-1-diethylamino-3-methoxybenzene% μm diazo-l-
Dimethylamino-λ-methylbenzene, μm shear”/
-/-henzoylaminoco, j-jethoxybenzene, μm diazo-l-morpholinobenzene, 4A-diazo-l-morpholino-λ, j-jethoxybenzene, hiro-diazo-7-morpholino-, j-dibutoxy Hensen, Dardiazole l-anilinobenzene.

μm diazo-/-) Ruylmercabuteau J,! -jethoxybenzene, l-diazo-1, Hiro-methoxybenzoylamino-2,! -jethoxybenzene and the like.

Specific examples of acid anions include “nFzn-HCOO-
(n is an integer from 3 to 2) -CmF2m+1sO1 (m is i
~r adjustment e) , (ctF'2z, 1SO2)2CH
-(L is an integer from 1 to If) 1 (n is an integer from 3 to 2) H3 (n is an integer from 3 to 2) oah Kicked.

In particular, among the acid anions, those containing a perfluoroalkyl group or a non-fluoroalganyl group or PF
, - are preferable because they cause less increase in fog during raw storage.

Specific examples of the diazo compound (diazonium salt) include the following examples.

C4H9 OC4Hg OC4)19 C2H3 C(C,'Hs　)　3 OC2H.

C4H9 C4H9 C4H9 The coupling agent used in the heat-sensitive recording material (3) of the present invention is one that forms a dye by coupling with a diazo compound (diazonium salt) in a basic atmosphere.2 Specific examples include resorcinol, Phloroglucin% λ, Sodium 3-dihydroxynaphthalene-2-sulfonate, l
-Hydroxy-λ-naphthoic acid morpholinopropylamide, l,! monodihydroxynaphthalene, 2,3-dihydroxynaphthalene, λ,3-dihydroxy-6-sulfanylnaphthalene, λ-hydroxy-3-naphthoic acid morpholinopropylamide, 2-hydroxy-3-naphthoic acid anilide, 2-hydroxy-(3 -Naphthoic acid-λ'-methylanilide, 2-hydroxy-3-naphthoic acid ethanolamide, 2-hydroxy-3-naphthoic acid octylamide.

2-Hydroxy-3-naphthoic acid-N-dodecyl-oxy-propylamide, euhydroxy-3-naphthoic acid tetradecylamide, acetanilide, acetoacetanilide, benzoylacetanilide, l-phenyl-3
-Methyl-j-vilazogone, /-(2', μ/, 1
/ ) Lichlorophenol)-3-benzamide-j-
Pyrazolone, l-(λ', Hiro/, A/2-lichlorophenyl)-? - Anilino, pyrazolone, l-phenyl-3-phenylacetamido-j-pyrazolone, etc. are falsified. Furthermore, by using these coupling agents in combination, images of arbitrary tones can be obtained.

As the basic substance used in the heat-sensitive recording material (3) of the present invention, there may be used a poorly water-soluble or water-insoluble base substance or a substance that generates dialkali when heated.

Basic substances include inorganic and organic ammonia salts, organic amines, amides, urea, thiourea and arsenic derivatives, thiazoles, virols, pyrimidines, piperazines, guanidines, indoles, imidazoles, and imidacillins. , triazoles, morpholines, piperidines, amidines, formazines, pyridines, and other nitrogen-containing compounds. Specific examples of these are:
Examples, ammonium acetate, tricyclohexylamine, tribenzylamine, octadecylbenzylamine,
Stearylamine, allyl urea, thiourea, methylthiourea, allylthiourea, ethylenethiourea, λ-benzylimidazole, μm phenylimidazole, cophenylu≠-methyl-imidazole, 2-undecyl-imidacillin, λ+”, -t) riflyruco-imidacillin% l.

Cophenyl-μ9μm dimethyl-2-imidasoline, copheny-2-imidacilline%'+λ, J-) liphenylguanidine% 1IJ-ditolylguanidine%
l,2-dicyclohexylguar”)7s/,
2, J-), link day hexylguar 1-)
=y, ya=')7h I), ooh*B% N, N
・-dibenzylpiperazine% μ @/-dithiomorpholine, morpholinium trichloroacetate, co-aminobenzothiazole% copenzoylhydrazinobenzothiazole. Two or more of these basic substances can also be used in combination.

Substances not contained in microcapsules are preferably used after being dispersed in solid form using a sand mill or the like. In the case of two or more types of substances, each substance is normally dispersed separately in a water-soluble polymer solution, but there is no limitation.

Preferred water-soluble polymers include water-soluble polymers used when making microcapsules. At this time, the concentration of the water-soluble polymer is 2 to 30 wt%, and the substance dispersed in this water-soluble polymer solution is j to 30 wt%.
It is invested so that it becomes.

As for the layered structure of the heat-sensitive material of the present invention, one or more heat-sensitive layers can be provided. When the heat-sensitive layer is one layer, two or more types of capsules having different glass transition points can be mixed and used. 1 engineering. . s8 engineering 1. , :, Talent 45, Ikaka, et al.
! It is advantageous to provide a high-sensitivity thermosensitive layer comprising capsules with a low glass transition point "as a system" followed by a low-sensitivity thermosensitive layer comprising capsules with a high glass transition temperature "as a system". You can do the same thing if you get three no's or more.

It is also possible to combine the case of the capsule described above with a multilayer configuration.

Furthermore, if the particle size of the substance outside the capsule has a finite value, it will not be completely melted by the heating of the thermal head, and will only be completely melted when the applied energy becomes large. In particular, when two or more substances in a solid dispersion state outside the capsule are eutectic, the above-mentioned phenomenon related to particle size is likely to occur, and this can be advantageously used when providing gradation.

In addition, providing a distribution in the wall thickness of the capsule can also be advantageously used in combination with the above-mentioned factors.

In the case of a multilayer structure, simultaneous multilayer coating is also possible in addition to sequential coating one layer at a time.

Thermosensitive recording material of the present invention (1), f21. (3) contains silica, barium sulfate, and titanium oxide for the purpose of preventing sticking to the thermal head and improving writing performance.

Pigments such as aluminum hydroxide, zinc oxide, and calcium carbonate, and fine powders such as styrene beads and urea-melamine resin can be used.

Similarly, metal soaps can also be used to prevent sticking. The usage amount of these is O0
λ~7y/m2.

Furthermore, the light and heat sensitive recording materials (1) and (2) of the present invention include:
Thermofusible materials can be used to increase thermal recording density. As a thermofusible substance, it is solid at room temperature and melts when heated by a thermal head, with a melting point of 30-/! It is a 0'C substance that dissolves ashes, leuco dyes, color developers, diazo compounds, coupling agents, or basic substances. The heat-fusible substance is dispersed in the form of particles of O9/, lQf and used in an amount of solid content θ, λ~71/m2. Specific examples of heat-melting substances include fatty acid amides, N1ff1-substituted fatty acid amides, ketone compounds, and Nil-converted carbamate compounds.

Examples include urea compounds and esters.

The heat-sensitive recording materials (11, (2), and (3)) of the present invention can be coated with a suitable binder.

Binders include polyvinyl alcohol, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, gum arabic, gelatin, polyvinylpyrrolidone, casein, styrene-butadiene latex, acrylonitrile-butadiene latex, polyvinyl acid, polyacrylate ester, ethylene-acetic acid. Various emulsions of vinyl copolymers can be used. The amount used is a solid content of 0.3-sf/m2.

In the present invention, in addition to the above materials, citric acid is used as an acid stabilizer.
Tartaric acid, oxalic acid, boric acid, phosphoric acid, and pyrophosphoric acid can be added.

The heat-sensitive recording materials (1), (2+ and (3)) of the present invention are applied by dispersing microcapsules containing one component that causes a color reaction and the other component in a solid state or by dissolving them as an aqueous solution and then mixing them. Prepare a liquid and apply it on a support such as paper or synthetic resin film using a par coating, blade coating, air knife coating, gravure coating, roll coating, or 3-f''/rmm%.
2-) t/-m7″1″f″″′j After coating and drying, solid content λ,! - A heat-sensitive layer of J f ,/m is provided.

The paper used for the support is heat extracted pH 6 sized with a neutral sizing agent such as an alkyl ketene dimer.
It is advantageous in terms of storage stability over time to use neutral paper (described in Japanese Patent Application Laid-open No. Sho!!-/4!27/).

In addition, in order to prevent the coating liquid from penetrating into the paper and to improve the contact between the recording heat source and the heat-sensitive recording layer,
, No. 417, paper having a (meter basis weight) 2 and a Beck smoothness of 0 seconds or more is advantageous.

Tokukai Akira again! Paper with an optical surface roughness of rμ or less and a thickness of μO to 7jμ as described in I-/j44 Paper with a contact rate of more than is%, Tokukaisho! l'
-Canadian standard r water level (JIS P
J/2/) paper beaten to a level of lAo occ or more by /ξrupu paper to prevent coating liquid from seeping in, Yankee machine as described in JP-A No. 5 A method for improving the color density and resolving power by using the glossy side of the paper-made base paper as the coating surface is described in Japanese Patent Application Shozy-tajr7J.

Papers whose base paper has been subjected to corona discharge treatment to improve coating suitability can also be used in the present invention and give good results.

In addition to these, any support commonly used in the field of heat-sensitive recording paper can be used as the support of the present invention.

Thermosensitive recording material of the present invention (1), +21. (3) is %
It has excellent gradation recording and can be used as printer paper for facsimiles and computer computers that require high-speed recording.Moreover, (2+, (3)) is heated and printed and then exposed to light to harden the capsules to make them inactive. The fixation can be achieved by converting the diazo compound into a diazo compound or by decomposing an unreacted diazo compound.

In addition, it can also be used as a heat-developable copying paper.

Examples are shown below, but the present invention is not limited thereto. Note that "parts" indicating the amount added represent "parts by weight."

"Example" Example 1 Two types of capsules were prepared using the following diazo compounds.

OC4 [-1° (Capsule liquid A) 2 parts of the diazo compound and 11 parts of the (J:/] adduct of xylylene diisocyanate and trimethylolpropane were added to a mixed solvent of 7 parts of digtylcodium talate and 5 parts of ethyl acetate, The solution of this diazo compound was gold, 3.5 parts of polyvinyl alcohol, 7 parts of gelatin, 4A-di(λ-hydroxyethoxy)benzene, q part of water sr.
The mixture was mixed with an aqueous solution dissolved in 100 ml of water, and emulsified and dispersed at 2ooC.

An emulsion with an average particle size of 3 μm was obtained. Add water io to the resulting emulsion.
After 2 hours, a capsule containing the diazo compound in the core material was obtained.

(Capsule liquid B) In the preparation of capsule liquid A, the following changes were made to prepare capsule liquid B.

In place of 177 parts of the (J:i) adduct of xylylene diisocyanate and trimethylolpropane, 17 parts of the same compound and 1 part of the (J:/) adduct of toluylene diisocyanate and trimethylolpropane were used. Capsule liquid B was obtained by performing the same procedure as capsule liquid A except for % l, ≠-di(cohydroxyethoxy)benzene λ, and μ parts from the composition of the aqueous solution.

Next, 2% cohydroxy-3-naphthoic acid anilide λO part was added to 10θ parts of a t% polyvinyl alcohol aqueous solution and dispersed in a sand mill for about 24 hours to obtain a dispersion of the coupling component with an average particle size of 3μ.

Next, 20 parts of triphenylguanidine was added to 100 parts of j% polyvinyl alcohol aqueous solution and dispersed in a sand mill for about 2 μ hours to obtain a dispersion of triphenylguanidine with an average particle size of 3 μ. -20 parts of p-benzyloxyphenol was added to 100 parts of a 1% aqueous polyvinyl alcohol solution and dispersed in a sand mill for about 2 hours to obtain a dispersion of p-benzyloxyphenol having an average particle size of 3 μm.

30 parts of capsule liquid A obtained as above, 820 parts of capsule liquid, and j parts of coupling acid.

13 parts of triphenylguanidine was added to make a coating solution, and this coating solution was coated on smooth high-quality paper (j Ot / ?Fl 2).
14Lf/m dry weight using coated rod.
2 and dried for 30 minutes at 4Aj0C to obtain a heat-sensitive recording material. The glass transition points of the capsule walls of capsule liquid A and capsule liquid B as a system are 120 and 120, respectively.
0C% lμO0C.

Example 2 A coupling acid dispersion Ij part and 73 parts of a triphenylguanidine dispersion were added to a capsule liquid Bzo part to prepare a first required coating liquid. Next, 13 parts of the coupling component dispersion and 1 part of the triphenylguanidine dispersion were added to 1 part of the capsule liquid.
Add 75 parts of 3% p-benzyloxyphenol and mix with the second layer coating solution.

Using a coating rod, the first and second layer coating liquids were applied in layers to a dry weight AP of 7f on high-quality paper (!1097m) and dried for 30 minutes to obtain a heat-sensitive recording material. I got it.

The glass transition point of the capsule wall used in the first coating solution is
0c, the glass transition point of the capsule wall and p-benzyloxyphenol interaction product used in the second layer coating liquid "as a system" was 10 to 00C.

Example 3 A heat-sensitive recording material was obtained in the same manner as in Example 2, except that an intermediate layer of polyvinyl alcohol (dry film thickness: 0.jtμ) was provided between the first layer and the second layer. Ta.

Comparative Example In Example 1, 30 parts of capsule liquid A and 3 parts of capsule liquid f
Use AjO parts of capsule liquid instead of 20 parts.

A heat-sensitive recording material was obtained in the same manner as in Example 1 except for this.

(Test Method) The obtained heat-sensitive recording material was thermally recorded by changing the applied energy, and then the entire surface was exposed to light using Ricope Sono ξ-Dry 1OO (manufactured by Ricoh ■) and fixed. - Recorded images obtained using a Macbeth reflection densitometer.

Blue density was measured. The results are shown in FIG.

"Effects of the Invention" From Figure 1, it is clear that Examples 1, 2% and 3 have smoother density changes, especially at low applied energy, and are excellent in gradation expression, compared to Comparative Examples.

[Brief explanation of drawings]

FIG. 1 shows the relationship between the energy applied to the heat-sensitive recording material and the print density. However, in Figure 1, curves (1) to (
4) represents the following. (11 Example 3121 Example 2, (3) Example 3% (4
) Comparative Example Patent Applicant: Fuji Photo Film Co., Ltd. Procedural Amendment January 32, 1949 1, Indication of the Case: Showa Tade, Japanese Patent Application No. g 711 2, Title of Invention: Thermal Recording Material 3, Amendments to be made Relationship with the case Patent applicant name (520) Fuji Photo Film Co., Ltd. 4, subject of amendment ``Detailed description of the invention'' column 5 of the specification, contents of the amendment ``Detailed description of the invention'' of the specification The description in this section has been amended as follows. (1) On page J, line 7, after “It gets better.” “The difference in the glass transition point of microcapsules is approximately λo.
20°C is preferred, particularly preferably about 20°C to /j
It is 00c. ” is inserted. (2) Number! Correct "1lr0C" in line 1 of page 10 to [/♂o O(J). (3) Correct "p-phenylene" in line j of page 7.2 to "p-phenylene". ( 4) Insert "Polyinsyanate can also react with water to form a polymer film." after "Can be done." on page 7.2, line 17. (5) Page 16, 72 Insert "(Use the same leuco dye for microcapsules with different glass transition points, or use several types of leuco dyes in the same composition ratio.)" after "Recording material." in the first line. °,) Procedure Amendment 1, Indication of the case, Showa J.I. Patent Application No. 197/l'2,
Title of the invention Thermal recording material 3, Relationship to the case of the person making the amendment Patent applicant Location 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture Name (52)
0) Fuji Photo Film Co., Ltd. 4, Subject of amendment Column 5 of "Detailed Description of the Invention" of the specification, content of amendment on page 37, line 4', after "is possible." It is also possible to expose the image to light and then uniformly heat it to thermally color the unexposed areas.''

Claims (1)

[Claims] A heat-sensitive material having microcapsules containing at least one component that causes a color reaction and an organic solvent in the core, and another component that develops a color by reacting with the component that causes a color reaction, on the same side of a support. As microcapsules, two or more types of microcapsules with different glass transition points of microcapsule walls