JPS61242886A - Multicolor thermal recording material - Google Patents

Abstract

PURPOSE:To obtain clear images while sufficiently controlling a developed color hue and preventing color blurring, by providing a multicolor thermal recording material wherein at least one of color forming components and color developer is enclosed in microcapsules, at least one of the color forming components is a diazo compound substantially decomposed by light, and at least one of the other color forming components is a compound substantially not decomposed by light. CONSTITUTION:The diazo compound which is one of essential constituents reacts with a color developer called a coupling component to form a color with a desired hue, but when it is decomposed by light before reaction, it loses the capability of forming a color under the action of the coupling component. The coupling component may be resorcinol, phloroglucinol or the like. Further, by using two or more coupling components in combination, it is possible to obtain images with an arbitrary tone. The color forming component which is substantially not decomposed by light may be a basic colorless dye and/or an acidic colorless dye used in ordinary thermal recording papers.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a heat-sensitive recording material, and particularly to a heat-sensitive recording material that develops multiple colors.

More specifically, printed images of different hues are reliably obtained by selectively photodegrading at least seven color components in a specific unit color group during thermal printing in a substantial sense. The present invention relates to a multicolor heat-sensitive recording material which can be used to record images without any unwanted color development during storage of unrecorded paper, and which has extremely good stability and storage stability of images after recording.

(Prior Art) With the rapid development of the information industry, there is an increasing demand for easily obtaining color hard copies from information equipment terminals such as computers and facsimiles. An inkjet method or a thermal transfer method is being considered as a method for this purpose. However, this menkjet method has a major drawback in that the nozzle is easily clogged with coloring material or other contents, resulting in a lack of recording reliability, since the ink is ejected from a thin nozzle. In addition, the thermal transfer method heats and melts the ink on the ink sheet in an image-like manner.
Since it is a method of transferring to paper, for example, if you want to obtain a double color image, you need to use two ink sheets! ! !
/Jl and requires a large amount of ink sheets, which is uneconomical.

Furthermore, in the case of the inkjet method, the user must always be careful not to run out of ink liquid, and in the case of the thermal transfer method, the user must always be careful not to run out of ink sheet.

That is, both methods force the user to perform complicated management.

On the other hand, a thermal coloring method is known as a highly reliable recording method that does not require such complicated management, and has rapidly become popular in the fields of black and white facsimiles and printers in recent years. This method is characterized by a recording material in which a layer having a color development structure is coated on a support, and since it is a simple method for users, it has been desired to develop a multicolor heat-sensitive color development method.

However, in order to produce multiple colors, it is necessary to incorporate a number of coloring mechanisms corresponding to the number of colors on the same support and to control each coloring mechanism to make it work, and many efforts have been made in the past. None of them had sufficient control over color development. The following is an example.

As a method proposed for this multicolorization, for example, Tokko Sho I? -4? As described in the issue, recording materials that use a mixture of one type of coloring component that develops different tones at different coloring temperatures in the same heat-sensitive coloring layer, or Tokkoshoyo/-
No. 17919, 52-/J, ? ? ? / issue, Tokukai Akira! l
l-1113! Same issue! ! -133 Tade No. 7, same! ! −
/JJ99 issue and 4It-izs4io issue, depending on the coloring temperature of the coloring component, it is used separately for the high-temperature heat-sensitive coloring layer and the low-temperature fouling coloring layer, and these two
There are recording materials in which layers are laminated one after another on a support. Moreover, Tokko Akira! 0-17g No. 66, same zi-sri No. 91,
In addition to the high-temperature and low-temperature development layers, a high-temperature thermosensitive coloring layer is used in the image forming section when forming an image, as shown in JP-A-53-161411. Examples include recording materials incorporating a color erasing agent that exhibits a color erasing effect on the color forming components in the low temperature thermosensitive color forming layer.

Furthermore, JP-A-5-33237 discloses a coating method in which a leuco dye, an acidic substance that causes the leuco dye to develop color when heated, a diazo compound, and a coupling component that causes the diazo compound to develop color when heated are solidly dispersed in water. It is described that a two-color recording material can be obtained by applying a liquid onto a support and drying it, followed by thermal printing, decomposition of the diazo compound by light irradiation, and thermal printing. However, all of these conventional multicolor heat-sensitive recording materials exhibit several drawbacks and are not satisfactory.

For example, when low-temperature and high-temperature coloring images with different tones are formed by low-temperature and high-temperature printing using a recording material having one or more heat-sensitive coloring layers on a support, the tone of the high-temperature coloring image differs from the low-temperature coloring. This causes color mixing with the color tone of the image, and when the printing conditions (temperature, humidity, printing model) change, the degree of color mixing changes, making it difficult to obtain an image with a constant and stable color tone. Furthermore, during high-temperature printing, an area with the same temperature as during low-temperature printing is generated around the high-temperature printing, so a low-silver generation area is generated around the high-temperature printing image. This phenomenon is generally referred to as shading or blurring, and has been a cause of deteriorating the clarity of images.

In addition, with recording materials that have a color erasing mechanism, is it possible to prevent color mixing?Not only is the problem of color bleeding still unresolved, but because a color erasing agent is added to the recording layer, it is difficult to prevent color mixing when exposed to high temperature and high humidity. When recording paper is placed on the paper, there have been problems such as the image becoming discolored or the sensitivity of unrecorded paper being reduced.

Furthermore, a leuco dye, an acidic color developer, and a diazo dye,
In materials containing coupling components as dispersions in the same layer, no matter how water-insoluble the individual dispersions may be, they come into contact with each other in the recording layer, resulting in a coloring reaction at the contact surface. This paper has disadvantages such as extremely poor background fogging and particularly poor storage stability of unrecorded paper under high temperature and high humidity conditions. Furthermore, although the coloring reaction between the diazo dye and the coupling component proceeds smoothly in a basic atmosphere, because the same layer contains an acidic color developer for the leuco dye, the coloring reaction of the diazo dye is not sufficient. However, this method has the disadvantage that it does not progress to the next stage, and therefore only images with poor sensitivity and hue can be obtained.

An object of the present invention is to provide a multicolor heat-sensitive recording material that is capable of obtaining a multicolor image in which the color hue is sufficiently controlled, and furthermore, is capable of obtaining a clear image without color bleeding.
We are a company that provides multi-color heat-sensitive recording materials with good shelf life, both on paper and on non-recording paper.

That is, the present invention provides a heat-sensitive recording material comprising at least one colorless or light-colored coloring component that develops colors in different hues on a support, and a color developer that reacts with the coloring component and develops color when heated. At least one of the color-forming components and/or color developer is encapsulated in microcapsules, at least one of the color-forming components is a diazo compound that is substantially decomposed by light, and the other color-forming components are encapsulated in microcapsules. This has been achieved with a multicolor heat-sensitive recording material characterized in that at least one of the components is a compound that is substantially not decomposed by light.

An example of the basic color development mechanism of the present invention is described below.

For example, if a diazo compound and a coloring component other than diazo are encapsulated in separate capsules, heating will melt the coupling component and soften the wall material of the diazo-containing capsule, making it permeable to the substance. Because of this, the molten coupling component enters the capsule, reacts with the diazo compound, and develops a certain color. Similarly, in the other capsule, a coloring component other than diazo reacts with another color developer to produce a different hue, and a mixture of both hues is formed as M rice. Next, after irradiating light that matches the decomposition wavelength of the diazo compound, and heating a part other than the above-mentioned heating part, the diazo compound has already decomposed, so no color develops, and the diazo compound does not develop any color. Only the hue of the reaction product of the color-forming component and the color developer can be obtained. In other words, two-color recording paper was obtained. Moreover, in this system, since the color-forming component is encapsulated in microcapsules, contact between this component and the color developer is reliably avoided at room temperature, resulting in unwanted color fogging at room temperature. It has the characteristic that it cannot be seen at all. Did I mention an example in which both types of color formers were microencapsulated?
What should be microencapsulated in each component may be selected at will depending on the combination of color former and color developer used. These will become clear in the more detailed description below. In addition, in the present invention, in order to set the coloring start temperature, a conventionally known coloring agent,
In addition to changing the melting point or eutectic point of the color developer, the temperature at which substances begin to pass through the microcapsule wall can be arbitrarily selected using the method described below. It has the advantage that you can get more than one color by selecting it.

The diazo compound, which is one of the essential components of the present invention, reacts with a color developer called a coupling component, which will be described later, to develop a desired hue, and receives light of a specific wavelength before the reaction. It decomposes and no longer has the ability to develop color even when a coupling component acts on it. The hue in this coloring system is mainly determined by the diazo dye produced by the reaction between the diazo compound and the coupling component. Therefore, as is well known, the coloring hue can be easily changed by changing the chemical structure of the diazo compound or the chemical structure of the coupling component, and almost any coloring hue can be obtained depending on the combination. I can do it.

For this reason, various diazo compounds may be dispersed in one layer, and l types of coupling components and other additives may be incorporated into the same layer. In this case, each unit coloring group is Consists of different diazo compounds, common coupling components and other additives. Also, there are combinations in which separate coupling components are dispersed in several layers and the same diazo and other additives are incorporated into each layer. At this time, each unit coloring group has a different coupling component,
Composed of diazo compounds and additives common to others. In any case, each unit color forming group is composed of seven or more diazo compounds that are combined to have different color hues, and one or more coupling components and other additives.

The photodegradable diazo compound referred to in the present invention mainly refers to aromatic diazo compounds, and more specifically refers to compounds such as aromatic diazonium salts, diazosulfonate compounds, and diazoamino compounds. Hereinafter, explanation will be given mainly using diazonium salt as a representative example. It is generally said that the photodecomposition wavelength of a diazonium salt is its maximum absorption wavelength. It is also known that the absorption maximum wavelength of a diazonium salt varies from about 1 oonm to 700 It Inn depending on its chemical structure ("Photolysis and chemical structure of photosensitive diazonium salts" Takahiro Tsunoda, Ao Yamaoka Written by Journal of the Photographic Society of Japan 29(4)/pages 97-20jt (1 Zoro 3) That is, when a diazonium salt is used as a photodegradable compound, it is decomposed by light of a specific wavelength depending on its chemical structure, and By changing the chemical structure of the diazonium salt, the hue of the dye changes when it undergoes a coupling reaction with the same coupling component, and can be preferably used in the present invention.

A diazonium salt is a compound represented by the general formula ArN2"X- (wherein Ar represents a substituted or unsubstituted aromatic moiety, N2+ represents a diazonium group, and X- represents an acid anion. ) In the present invention, it is one of the desirable embodiments to use diazonium compounds with different photolysis wavelengths, but examples of compounds with photolysis wavelengths around 4 Ioonm include daazo/-dimethylaminebenzene, daazo-7- Diethylaminobenzene, goudiazo-l-dipropylaminobenzene, goudiazo-l-methylbenzylaminobenzene, !-siat-t-dibenzylaminobenzene, dardiazo/
-Ethylhydroxyethylaminobenzene, dahdiazo-l-diethylamino-j-methoxybenzene, dahdiazo-l-dimethylamine-comethylbenzene, dahdiazo-l-benzoylamino-13-jethoxybenzene, dahdiazo-i-morpholinobenzene, dahdiazo- 1-morpholino-2,3-jethoxybenzene, derdiazo/-morpholino-2,s-dibutoxybenzene, diazo-t-anilinobenzene, derdiazo/-toluylmel-ptoco.

Examples include 3-jethoxybenzene, derdiazo/, dermethoxybenzoylaminoco, j-jethoxybenzene, etc. Compounds having a photolysis wavelength of 300 to 370 nm include /-diazo-q-(N,N −
dioctylcarbamoyl)benzene, l-diazo-octadecyloxybenzene, l-thiasota-(l
I-tert-octylphenoxy)benzene, l-
Sheasorter (J, q-ditertiary-amylphenoxy)benzene, l-diazo-J-(lI-tert-octylphenoxy)benzene, t-diazo-3-
Chloro-(4-tert-octylphenoxy)benzene, l-siacy-, z-bis-octadecyloxybenzene, l-diazo-λ.

Sorbis-octadecyloxybenzene, l-diazo-
Examples include a-(N-octylteraroylamino)benzene and the like. The aromatic diazonium compounds represented by the examples listed above can have their photodecomposition wavelengths varied over a wide range by arbitrarily changing the substituents.

Specific examples of acid anions include CnF2n+IC0O-
(n represents 3 to de), CmF2m÷ISO3-(m
represents J ~ ff), (CLFzL+ISO2)
Examples include 2Cf(-(t represents 1 to 7g)), CH8BF4-, PFa-, and the like.

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

oc4H,.

C2H5 The diazosulfonate compound that can be used in the present invention is a compound represented by the general formula %. In the formula, %R1 is an alkali metal or ammonium compound R2% R3s R5 and R
6 is hydrogen, halogen, alkyl group, or alkoxyl group, and R4 is hydrogen, halogen, alkyl group, amino group, benzoylamido group, morpholino group, trimercapto group, or pyrrolidino group.

A large number of such diazosulfonates are known and can be obtained by treating each diazonium salt with a sulfite.

Preferred compounds among these compounds include comethoxy, -monophenoxy, -monomethoxyderphenoxy, co,41-dimethoxy, comethyl-goomethoxy,
-, Gooji Methyl, J, 4t, A.

-benzenediazosulfonates with substituents such as trimethyl, gouphenyl, gouphenoxy, gouacetamide, etc., or alternatively 1-(N-ethyl, N-benzylamino), ter(N,
N-dimethylamino), Gu (N, N-diethylamino), 4t-(N, N-diethylamino)-J-chlor, Guvirodinino, ? -chlor, morpholinocomethoxy, +-(1/methoxybenzoylamino)-
a, S-dibutoxy, Gu (41'-trimercapto)
It is a benzenediazosulfonic acid salt having a substituent such as -2,S-dimethoxy. When using these diazosulfonate compounds, it is desirable to irradiate the diazosulfonate with light to activate the diazosulfonate before printing.

Moreover, as a diazo compound that can be used in the present invention,
Diazoamino compounds can be extracted. Diazoaminated foods include compounds in which a diazo group is coupled with dicyandiamide, sarcosine, methyltaurine, N-ethylanthranic acid-5-sulfonic acid, monoethanolamine, jetanolamine, guanidine, etc.

The coupling component as a color developer for the diazo compound used in the present invention is one that forms a dye by coupling with the diazo compound (diazonium salt) in a basic atmosphere, and specific examples include resorcinol, phloroglucin, Ko. Sodium 3-dihydroxynaphthalene-6-sulfonate, l-hydroxy-naphthoic acid morpholinopropylamide, 1.3-dihydroxynaphthalene, 2.3-dihydroxynaphthalene, -3-dihydroxy-6-sulfanylnaphthalene, cohydroxy-3 -naphthoic acid morpholinopropylamide, -monohydroxy-3-naphthoic acid modified anilide, -monohydroxy-3-naphthoic acid-λ'-methylanilide, co-hydroxy-3-naphthoic acid ethanolamide, euhydroxy-3-naphthoic acid octylamide, CO-HYDROXY 3
-Naphthoyl-N-dodecyl-oxy-probylamide, -monohydroxy-3-naphthoic acid tetradecylamide, acetanilide, acetoacetanilide, benzoylacetanilide, l-phenyl-J-methyl-j-
Pyrazolone, 1-(Co1.da'6'-toIJ90lophenyl)-3-benzamido-3-pyrazolone, /-
(J/, lII, 4/-trichlorophenyl)-3-anili/-1-bi5zolone, l-phenyl-3-phenylacetamido-S-pyrazolone, l-
hydroxy-λ naphthoic acid morpholinopropylamide,
-monohydroxy-J-naphthoic acid morpholinopropylamide and the like. Furthermore, by using one or more of these coupling components in combination, an image of any color tone can be obtained. Since the coupling reaction between these diazo compounds and the coupling component is likely to occur in a basic atmosphere, a basic substance may be added to the layer.

As the basic substance, a poorly water-soluble or water-insoluble basic substance or a substance that generates alkali when heated is used. Examples include inorganic and organic ammonium salts, organic amines, amides, urea and thiourea and their derivatives, thiazoles, virols, pyrimidines, piperazines, guanidines, indoles, imidazoles,
Examples include nitrogen-containing compounds such as imidacillins, triazoles, morpholines, piperidines, amidines, formazines, and pyridines. Specific examples of these include ammonium acetate, tricyclohexylamine, tribenzylamine, octadecylbenzylamine, stearylamine, allyl urea, thiourea, methylthiourea, allylthiourea, ethylenethiourea, -pendylimitasol, and gouphenyl. imitasol, -1-phenyl-goomethyl-imitasol, conundecil-imidazoline, 'e'e'l'rifryl-λ-imitasoline, l-1 diphenylruta, tadimethyl-imitasoline, 2-phenyl- imidazoline, /
2.3-triphenylguanidine, /, J-ditolylguanidine, /,! -dicyclohexylguanidine, /,
2.3-Tricyclohexylguanidine, guanidine trichloroacetate, N,Nl-dibenzylpiperazine, Hiromu.

These include -dithiomorpholine, morpholinium trichloroacetate, -monoaminobenzothiazole, and -1penzoylhydrazinopenzothiazole. One or more of these basic substances may be used in combination.

Next, a coloring component that is not substantially decomposed by light, which is another essential component of the present invention, will be described.

The color-forming component that does not substantially decompose with light may be a basic colorless dye and/or an acidic colorless dye that is conventionally well known and used in ordinary heat-sensitive recording paper. That is, basic colorless dyes have the property of donating electrons or accepting protons such as acids to develop color, and are not particularly limited, but are generally colorless and include lactones, lactams, sultones, and spiropyrans. Compounds having partial skeletons such as , esters, and amides, and which ring-open or cleave these partial skeletons upon contact with a color developer are used. Specifically, crystal violet lactone, benzoylleucomethylene blue, malachite green lactone, rhodamine B lactam.

/,,? ,,? -trimethyl-6'-ethyl-gl-butoxyindolinobenzospiropyran and the like.

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

Especially melting point so0~. 2j-0'C, particularly preferably L< is aO'~, 200'C, a phenol or organic acid which is sparingly soluble in water is desirable.

Examples of phenolic compounds include +, l-isopropylidene-diphenol (bisphenol A), p-1er
t-butylphenol, J,II-dinitrophenol, 3. lI-dichlorophenol, Dow ll-methylenebis(,2,A-di-tert-butylphenol), p-phenylphenol, p,4I-cyclohexylidene diphenol, co,coI-methylenebis(4I-
1 tert-butylphenol), J, co'-methylenebis(α-phenyl-p-cresol)thiodiphenol, p,l-thiobis(6-tert-butyl-1-cresol), sulfonyldiphenol, 7. In addition to l-bis(terhydroxyphenyl)-n-dodecane, p,4t-bis(lI-hydroxyphenyl)-l-pentanoic acid ethyl ester, p-tert-butylphenol-
Examples include formalin condensate and p-phenylphenol-formalin condensate.

Examples of the organic acid or its metal salt include J-tert-butylsalicylic acid sj, j-tert-butylsalicylic acid,! -α-methylbenzylsalicylic acid, 3,3-di-α
-Methylbenzylsalicylic acid, J-tert-octylsalicylic acid, S-α, r-dimethyl-α-phenyl-r
-Phenylpropyl salicylic acid and the like and their zinc, lead, aluminum, magnesium, and nickel salts are useful.

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

Next, examples of acidic colorless dyes include compounds such as PH indicators, such as phenolphthalein, fluorescein, copolymer, #,
! , A-tetrachlorofluorescein, tetrabromophenol blue % "I" @6.7-titrabromophenolphthalein, eosin, alarin cresol red, -1-naphtholphenolphthalein, etc., or are limited to these. It's not a thing.

The color developing agent that reacts with these acidic colorless dyes to develop a color is a basic substance or a substance that generates an alkali upon heating, and any of the above-mentioned basic substances are preferably used.

Next, as can be seen from the example described in 9, microcapsules, which is another requirement of the present invention, prevent contact between substances inside and outside the capsule at room temperature due to the substance isolation effect of the microcapsule wall, and are heated above a certain temperature. Only while
It increases the permeability of a substance. This phenomenon is a new technology discovered by the present inventors, and it is possible to freely control the permeation start temperature by appropriately selecting the capsule wall material, capsule core material, and additives.
The present invention was achieved by finding that this permeation start temperature corresponds to the glass transition temperature of the capsule wall.

In order to control the glass transition point specific to the capsule wall, it is necessary to change the type of capsule wall forming agent. Polyurea, polyurethane, polyurea/urethane mixed capsule urea-
Particularly preferred are formalin capsules, polyurea/other synthetic resin mixed capsules in which a ready-made synthetic resin is encapsulated in the core material, polyurethane/other synthetic resin mixed capsules, polyester, polyamide, and the like capsules.

The microcapsules of the heat-sensitive recording material of the present invention are made by emulsifying a core material and then forming a wall of a polymeric material around the oil droplets. The actant forming the polymeric material is added to the interior of the oil droplet and/or to the exterior of the oil droplet. Specific examples of the polymeric material include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene-methacrylate copolymer, styrene-acrylate copolymer, and the like.

The microcapsule wall of the present invention is particularly effective when using a microencapsulation method by polymerizing a glue actant from inside an oil droplet. That is, it is possible to obtain capsules suitable as a recording material having a uniform particle size and excellent shelf life in a short period of time.

This method and the specific side number of the compound are described in the specifications of US Pat.

For example, when polyurea polyurethane is used as a capsule wall material, a polyvalent incyanate and a second substance that reacts with it to form the capsule wall (e.g., polyol, polyamine) are mixed into the aqueous phase or the oily liquid to be encapsulated, and then submerged in water. By emulsifying and dispersing and then increasing the temperature, a polymer formation reaction occurs at the oil droplet interface, forming microcapsule walls. At this time, a co-solvent with a low boiling point and strong dissolving power may be used in the oily liquid. Polyurea is produced with or without the second additive.

In the above cases, regarding the polyisocyanate to be used and the polyol and polyamine to be reacted with it, please refer to U.S. %il'l-3λgi, Yza No. 3, No. 377 JAYj, No. 3 Kude 3 Korog, and Japanese Patent Publication No. 41 Zaichi. No. 4IOJ4I, No. 9-Col/S, No. 10/91 of the same patent, and No. 6 of Japanese Patent Publication No. 4IOJ4I, and they can also be used.

Furthermore, a tin salt or the like can also be used in combination to promote the urethanization reaction.

Further, the glass transition point of the wall can be changed widely by appropriately selecting the polyvalent isocyanate as the first wall film-forming substance and the polyol or polyamine as the second wall film-forming substance.

The glass transition point “as a system” is particularly important for polyurea, polyurethane capsules, urea compounds, fatty acid amides,
It can be changed by adding a hydroxy compound, a carbamate ester, an aromatic methoxy compound, etc. in a solid dispersion state. In that case, the amount of the glass transition point regulator may be 0.07 to 10 parts by weight per 1 part by weight of the capsule.

This glass transition point is determined by connecting the capsule wall or (capsule wall/glass transition point adjusting agent outside the capsule) interacting substance to Pybron ((DDV-1 [type], Toyo Baldwin ■ back)
This is the peak temperature of Tan δ, which is the dynamic loss modulus divided by the storage modulus.

Preparation of the capsule wall or the interaction product between the capsule wall and other components for measurement of the glass transition point is performed, for example, as follows.

Xylylene diisocyanate as a capsule wall component/
Trimethylolpropane (3:l adduct) - 0 parts in 30 parts of ethyl acetate was coated with a bar on a polyethylene sheet and reacted in water at 0 to 0 C. After peeling, 2
4! 'C, A1% R, H, air-dried for 1 day, lθ~-
A polyurea film with a thickness of 〇μ was obtained. This is a sample for measuring the glass transition point of the capsule wall alone. As a method for preparing an interaction product between a heat-fusible substance and a capsule wall, the above-mentioned polyurea film was immersed in a 10-methanol solution of p-benzyloxyphenol for 30 hours, and then heated at 2110C.

A4Iq6R6H, air-dried for 7 days and used as a sample.

Can water-soluble polymers be used as protective colloids when making microcapsules?Water-soluble polymers include water-bathable anionic polymers, nonionic polymers, amphoteric polymers, and anionic polymers. For example, -000 can be used either naturally or synthetically.
Examples include those having -1-S Oa - groups. Specific examples of anionic natural polymers include gum arabic,
There are alginic acids, etc., and semi-synthetic products include carboxymethyl cellulose, phthalated gelatin, sulfated starch,
Examples include sulfated cellulose and lignin sulfonic acid.

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

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 an aqueous solution of o, oi to /Qwt%.

If the organic solvent used as the core substance used in the present invention has a low boiling point, there will be evaporation loss during raw storage.
The above are preferred, and those without vinyl polymerization ability include phosphoric acid esters, phthalic acid esters, other carboxylic acid esters, fatty acid amides, alkylated biphenyls,
``Alkylated turf kingyl, chlorinated paraffin, alkylated naphthalene, diarylethane, etc. are used. Specific examples include tricresyl phosphate, trioctyl phosphate, octyldiphenyl phosphate, tricyclohexyl phosphate, cresyl diphenyl phosphate, dibutyl phthalate, dioctyl phthalate, dilaurate phthalate, dicyclohexyl phthalate, butyl oleate, and diethylene glycol diphthalate. Benzoate, dioctyl sepacate, sebacin V di-tyl, dioctyl adipate, trioctyl trimellitate, acetyltriethyl citrate, octyl maleate, dibutyl maleate, isopropylbiphenyl, inamyl biphenyl, diisopropylnaphthalene, 1. Examples include lI-ditolylethane, λ, I/--ditertiary amylphenol, and N,N-dibutyl-cobutoxy-3-tertiary octylaniline. Vinyl compounds can also be used as organic solvents.

Any component among the diazo compound, coupling component, color forming component other than diazo, color developer, and basic substance can be contained in the microcapsules independently or in combination. Nu, one or more diazo compounds, coupling components, basic substances, coloring components other than diazo, and color developers may be encapsulated in the same capsule or in different microcapsules. . These components may be used by being dissolved in the above-mentioned organic solvent or by being dispersed in the form of fine particles.

When making microcapsules, they can be made from an emulsion containing θ, 2 wt% or more of the component to be microencapsulated.

The amount of coupling component is 0.0% per 1 part by weight of the diazo compound.
/-10 parts by weight, and the basic substance is preferably used in a proportion of 0.7 to 20 parts by weight.

In addition, the amount of the color developer is 0.0.
It is preferable to use J-/1.0 parts by weight, preferably 0.3 to 0.3 to gO parts by weight.

In the present invention, it is also possible to use a color development aid.

The color development aid that can be used in the present invention is a substance that increases the color density during heating printing or lowers the minimum color development temperature, and may include a coupling component, an alkali, a color former, a color developer, or a diazo compound. By lowering the point or softening point of the capsule, the diazo, alkali, coupling component, color forming agent, and color developer may be more likely to react.

Coloring aids include phenolic compounds, alcoholic compounds, amide compounds, sulfonamide compounds, etc.
Specific examples include pt-octylphenol, p-benzyloxyphenol, p-, t-1-phenyl cybenzoate, benzyl carbanylate, phenethyl carbanylate, hydroquinone dihydroxyethyl ether, xylylene diol, N-hydroxyethyl Compounds such as -methanesulfonic acid amide and N-phenyl-methanesulfonic acid amide can be mentioned. These may be contained in the core material or may be added outside the microcapsules as a dispersion.

The heat-sensitive recording material of the present invention contains silica, barium sulfate, titanium oxide, aluminum hydroxide, zinc oxide,
Pigments such as calcium carbonate, fine powders such as styrene beads, urea-melamine resin, etc. can be used.

Similarly, metal soaps can also be used to prevent sticking. The amount of these used is O6
-~rit/m2.

The heat-sensitive recording material 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 acetate, polyacrylic acid ester, ethylene-vinyl acetate, etc. Polymers can be used. The amount used is a solid content of 0.3 to j f / 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, birophosphoric acid can be added.

When the diazo compound, coupling component, basic substance, color forming component other than diazo, and color developer used in the present invention are not microencapsulated, they may be used after being dispersed in solid form using a sand mill. In this case, each is separately dispersed in a water-soluble polymer solution. Preferred water-soluble polymers include water-soluble polymers used when making microcapsules. At this time, the concentration of water-soluble polymer is 2 to 3
The diazo compound, the coupling component, the basic substance, the color forming component other than diazo, and the color developer are each added in an amount of S to 10 wt% jζ with respect to this water-soluble polymer solution.

The dispersed particle size is preferably lθμ or less.

In the recording material of the present invention, at least seven types of diazo compounds, coupling components, basic substances, color forming components other than diazo, and color developers are dissolved or dispersed in an organic solvent and then microencapsulated.

The remaining reactive substances are either solidly dispersed or made into an aqueous solution, mixed with the aforementioned microcapsule dispersion liquid to make a coating liquid, and coated on a support such as paper or synthetic resin film with a bar, blade, or air knife. , applied by a coating method such as gravure coating, roll coating, spray coating, dip coating, etc. and dried to obtain a solid content of 5~/j f
/ m 2 of heat-sensitive layer is provided. Another method includes a layered structure in which a microcapsule layer containing a reactive substance and an organic solvent and a layer containing the remaining reactive substance are provided side by side.

Paper can be particularly advantageously used as the support of the present invention, but pigments such as charcoal, kaolin, talc, alumina, etc. can be mixed with polyvinyl alcohol, gelatin, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose synthetic resins, etc. Paper coated with a liquid dispersed in latex and dried may also be used.

The heat-sensitive recording material of the present invention can be used as printer paper for facsimiles and electronic computers that require high-speed recording. In this case, unlike ordinary facsimile machines and printers, it is necessary to have an exposure zone for photolysis. There are two methods for arranging the print head and the exposure zone.One is to irradiate light for photolysis after printing once, and the feeding mechanism for recording material relies on this light irradiation. As a result, the recording material returns to its state at the time of printing so that it can be printed again at the location where it was printed once. Next again,
One is the so-called multi-head scan method, which repeats the operations of printing, irradiating light, and returning the recording material to the original source.The other method has as many recording heads as the number of colors desired to be recorded.
A so-called multi-head with a light irradiation zone between them.
It is a scanning method, and both methods may be combined as necessary.

Further, the thermal energy applied to the head may be changed as necessary. Furthermore, as a light source for photolysis, it is possible to use a solid light source that emits light of a desired wavelength, such as a fluorescent lamp, a fluorescent lamp used in wet diazocopy, or a fluorescent lamp used in electrostatic photography. Various light sources can be used, such as fluorescent lamps, xenon lamps, xenon flash lamps, low-pressure, medium-pressure, high-pressure, and ultra-high-pressure mercury lamps, photographic flashes, strobes, and the like. Further, in order to make the optical constant zone compact, the light source section and the exposure section may be separated using an optical fiber.

In some cases, it is also possible to obtain a multicolor sample by placing the once-printed distribution material under sunlight or a fluorescent lamp, fixing it mainly with light in the visible light range, and then printing again.

The above an<, by microcapsulating the constituent substances of the color-forming group to cause reactions of only the necessary substances when necessary, and by using a color-forming agent that is deactivated by light and a color-forming agent that is not deactivated, A multicolor heat-sensitive recording material was obtained that had an excellent hue, excellent storage stability on both sides, and an excellent texture, which had not been previously available. Preferred embodiments based on the present invention are listed below, but the present invention is not limited to this scope.

(1) Diazo compound, coupling component, acidic colorless dye,
A diazo compound or microcapsule in a system containing a basic substance as the minimum essential component.

(2) In the minimum essential component system of (1), diazo compounds, acidic colorless dyes, or other substances encapsulated in separate capsules.

(3) In (1), diazo compounds or one or more compounds that develop colors in different hues, each of which is encapsulated in microcapsules having walls with different color initiation temperatures.

(4) In (2), acidic colorless dyes or one or more types of dyes that develop colors in different hues are encapsulated in microcapsules each having walls with different color initiation temperatures.

(5) In (2), one or more of the diazo compounds and acidic colorless dyes that develop colors in different hues, each of which is encapsulated in microcapsules having different color initiation temperatures.

(6) In a system containing a diazo compound, a coupling component, a basic substance, a basic colorless dye, and an acidic color developer as the minimum essential components, the diazo compound and the basic substance are encapsulated in the same microcapsule. thing.

(7) In the minimum essential component system of (6), the diazo compound h1 is encapsulated in microcapsules, and a layer containing the diazo compound and a basic substance is separated from a layer containing a basic colorless dye and an acidic color developer. mz as a layer of.

(8) In a system containing a diazo compound, a coupling component, a basic colorless dye, and an acidic color developer as the minimum essential components, the coupler is basic and the diazo compound is encapsulated in microcapsules. .

(9) In (6), the basic colorless dye is encapsulated in another microcapsule.

(In 30(7), a basic colorless dye is encapsulated in a separate microcapsule.

0υ In (8), a basic colorless dye or another encapsulated in microcapsules.

(In the minimum essential component system of 121(1), the coupling component is encapsulated in microcapsules.

(Examples) Specific examples of the present invention will be described below in the following examples, but the present invention is not limited thereto.

Note that "Miyako" indicating the amount added represents "parts by weight."

Example 1 Capsule liquid A was mixed and added to 100 parts of polyvinyl alcohol water sg4,113 (ff!t% dissolved) in distilled water, and emulsified and dispersed at 0'C to form an emulsion with an average particle size of 2μ. I got it. The resulting emulsion was kept stirring at 1 Io0c for 3 hours.

After cooling this liquid to 20°C, Amberlite IR-/-
〇B (manufactured by Rohm and Haas) was added in 1Q Q CC, stirred for 1 hour, and then treated with P to obtain camphor liquid.

Capsule liquid B was mixed, 63 parts of polyvinyl alcohol aqueous solution (weight S>100 parts of distilled water) was added, and the mixture was emulsified and dispersed at 20°C to obtain an emulsion with an average particle size of Continue stirring the emulsion at θ0C for 3 hours,
Capsule liquid B was obtained.

Capsule liquid C Basic colorless dye p, r part and (J-near) adduct of xylylene diisocyanate and trimethylolpropane 1
11 parts of a mixed solvent of 1 part of diphenylethane and 3 parts of ethyl acetate were added and dissolved.

This basic colorless dye solution was mixed with an aqueous solution of polyvinyl alcohol partially dissolved in water, and emulsified and dispersed with Co'C to obtain an emulsion with an average particle size of 3 μm.

Add 100 parts of water to the obtained emulsion, and stir while stirring.
The mixture was heated to θ0C, and after one hour, a microcapsule liquid C containing the following basic colorless dye in the core was obtained.

[Dispersion liquid A]

70 parts of the following compound! - In addition to 100 parts of an aqueous polyvinyl alcohol solution, about 21 parts were dispersed in a sand mill for a period of time to obtain a dispersion A of a blue color-forming coupling agent having an average particle size of 3 μm.

Compound [Dispersion B] /,! -dicyclohexyl-3-phenylguanidi27
0 part was added to 100 parts of a 6% polyvinyl alcohol aqueous solution and dispersed in a sand mill for about 24 hours to obtain a dispersion B of l,co,3-triphenylguanidine having an average particle size of 3μ.

[Dispersion liquid C]

10 parts of p-benzyloxyphenol was added to 100 parts of a 1% aqueous polyvinyl alcohol solution and dispersed in a sand mill for about a few hours to obtain a dispersion C of p-benzyloxyphenol having an average particle size of 3 μm.

[Dispersion D]

70 parts of bisphenol A was added to 100 parts of a 3% polyvinyl alcohol aqueous solution and dispersed in a sand mill for about λ hours to obtain a dispersion of bisphenol A having an average particle size of 3 μm.

Recording paper A Capsule liquid A, 70 parts, Capsule liquid 823 parts, Dispersion liquid A
A coating liquid A was prepared by adding a portion of the COPS dispersion Bjo and a portion of the dispersion Cxs. Place the coating liquid on smooth high-quality paper (!rO9/m2
) to a dry weight of 1,000 ml.
, yo minutes to obtain a recording sheet. Obtained recording paper A
When heated at 100°C for 7 seconds using a heat block, a blue-purple image was obtained. (Reflection density/ ,,2)
Next, after irradiating the recording paper with light for 10 seconds using a Rifby Super Dry 100 conveyor,
Similarly, when a hot plate was pressed for 7 seconds, a red color developed.

(Reflection Density (OD) O, f) As shown above, when printed before t light irradiation, a blue-purple color develops, and when printed after light irradiation and photodecomposition of the diazo compound, a red color develops on the same recording paper. There was no color bleeding in this colored image, and no mixing of blue components into the red color was observed.

Recording paper B Capsule 1dkJO part, Dispersion liquid 830 parts, Dispersion liquid A10
Coating liquid B was prepared by mixing the two parts. Nu, Capsule liquid C, 2j
Coating liquid C was prepared by mixing @ and dispersion liquid 1)/j part. or,
Dispersion C was directly used as a coating liquid.

These coating solutions B, C, and D were coated on smooth high-quality paper so that the dry weight was 4' f/m2, respectively.
Recording paper B was obtained by sequentially laminating and coating sheets B and drying each sheet for 30 minutes at 4Io0c. When the resulting recording paper B was heated at 130° C. for 1 second using a heat block, a green image was obtained. Next, this recording paper B was irradiated with light in the same manner as recording paper A, and then printed again in the same manner using a heat block, and a clear yellow image was obtained.

In addition, in order to check the raw storage stability, lIo °CX90%R,H
, X/day forced aging test also performed similar thermal printing. In order to investigate the resistance to contact with the diazo paper after copying, the diazo paper immediately after copying was contacted with the paper for 3 hours, and then an increase in fog in the background area was examined.

In order to examine light resistance, after exposure to sunlight for t hours, decolorization of the printed area and increase in fogging of the background area were examined. To examine solvent resistance, Cemedine was applied to the surface and then the presence or absence of fogging was examined. In order to examine the scratch resistance, the surface was scratched with a fingernail and the presence or absence of color development was examined.

Both recording paper A and B showed extremely strong resistance with no change before and after the forced test.

Patent applicant Fuji Photo Film Co., Ltd. 1933/J
Month/Rho Day 1, Indication of the case: 1933, Patent Application No. tzyoa No. 2, Title of the invention: Multicolor thermal recording material 3, Person making the amendment: Relationship with the case: Patent applicant: Location: 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture Contact: Address: 2-26-30 Nishi-Azabu, Minato-ku, Tokyo 106 Table Target of amendment: “Detailed description of the invention” section of the specification & Contents of amendment The description of the “Detailed description of the invention” section of the specification is as follows. Correct the standard.

I) Between lines 71 and 17 on page 4 "(Problem to be solved)" Insert.

e) Between page 7, line 7 and line 2 "(Means for solving the problem)" Insert.

J) Page 13/Line J rcmFzm+/SOs J rcmFzm+tsOs-J and correct it.

Reference) After "Color-forming component other than diazo" on page JJ, line 76, insert "Color-forming component other than diazo, preferably O0/-10 parts by weight per 7 parts by weight of the diazo compound."

Claims (1)

[Claims] A heat-sensitive recording material comprising, on a support, at least two colorless to light-colored coloring components that develop colors in different hues, and a color developer that reacts with the coloring components to develop color when heated. At least one of the components and/or color developer is encapsulated in microcapsules, and at least one of the color forming components is
A multicolor heat-sensitive recording material characterized in that the material is a diazo compound that is substantially decomposed by light, and at least one of the other color-forming components is a compound that is not substantially decomposed by light.