WO1986005448A1

WO1986005448A1 - Color-developing sheet for image-recording material

Info

Publication number: WO1986005448A1
Application number: PCT/JP1986/000135
Authority: WO
Inventors: Takahiro Torii
Original assignee: Mitsubishi Paper Mills, Ltd.
Priority date: 1985-03-23
Filing date: 1986-03-20
Publication date: 1986-09-25
Also published as: AU5587786A; JPS61217281A; AU573972B2

Abstract

A color-developing sheet comprising a support having provided thereon a layer containing an electron-acceptive color-developing agent which enables color formation of an electron donating leuco dye, which is to be used in combination with a color-forming sheet comprising a support having provided thereon an electron-donating leuco dye layer, and which contains an inorganic color-developing agent and an acrylic latex. This sheet can improve smoothness, remove smudge, and improve printability.

Description

Detailed color development for image recording materials Technical field

The present invention relates to a color developing system for image recording materials.

Background technology

It is well known as an image recording material using a color-forming reaction by a combination of an electron-donating colorless (α-ico) dye and an electron-accepting developer, for example, US Pat. 0 5, 4 7 0, circumference 2, 5 5 0, 4 71 1, circumference .. 2, 7 3 0, 4 56, circumference 3, 4 1 8 .2 5 0 There is a type of nor-carphone pressure-sensitive recording material, which has a long history and is well developed as an industry. There are other image recording materials that utilize this coloring principle. For example, a ripening sublimable colorless (roico) dye thermochromic image recording material (Japanese Patent Laid-Open No. 52-114, Ί23). , Publication No. 5 4 — 5 3, 5 38, etc.>, and maturing and maturing transfer color image recording materials.

The nokerpon pressure-sensitive recording material basically consists of a colorless (loico) dye donor sheet (upper sheet) and a color development sheet (lower sheet) (in addition to this). Some of the upper and lower gauze have a medium-use cane in the mouth, some applied products such as a self-contained cane), and a colorless (loico) dye is dissolved in a high boiling point solvent. In many cases, it is built into the power bus.

Micro-encapsulation is more conventional than the coacervation method, In-situ polymerization, interfacial polymerization, etc. are used. For colorless (roico) dyes, crystalline dyes, 3, 3-(P-Dimethylamminephenyl) Naphtalide, 3-(P-Dimethylamminephenyl)-3-(2-Methylindol- 3-ILL)-6-REAL REAL METAL TAILIDE, such as dimethyl methylamine, benzil, vinyl, vinyl, vinyl Acrylic derivatives such as paroyl, 3-Diethylamino-6-methyl-7-chlorofluoroamine, 3-diethylamino-7-dibenzylamino MINOL FULL ORANGLE, 3-JETHYL AMINO-6-METHYL-7-ANNILINO FULL ORAN, 3-METHYL-CYCLOHEXIL -Methyl-7-aniline full-orange, 3-Ethyl-p-U-lilyamino- 6-methyl- 7-aniline full-orange There are dye-based dyes and other dye dyes.

High boiling point solvents, which are often used for pressure sensitive recording materials, are alkylnaphthalene compounds represented by diisopropy lnaphthalene, 1-frone. Ene-1-Jaryl alkanes typified by xylylene, alkyrbi phenyl alkenyl typified by isopropyl biphenyl, Aromatic hydrocarbons such as polyarylmethanes, alkylbenzenes, benzilnaphthalene diarylalkylenes, arylindines, etc .; Carboxylic acid ester compounds represented by dibutyl tartrate, dialkyl maleic acid, etc .: Phosphoric acid represented by acrylic acid phosphate Ester compound: castor Naturally occurring animal and vegetable oils and fats or modified products thereof such as silicone oil, soybean oil, cottonseed oil, and hake oil: high-boiling fractions of natural products such as mineral oil (which are derived from aliphatic hydrocarbons).

The electron-accepting color developer is an acidic white clay, which is an inorganic white colorant, a natural clay mineral such as atapargai, clay, and a monilironite-based clay mineral. Various types of phenol compounds and nopolola are used as the activated white clay organic developer in which the soil is treated with an inorganic acid (mineral acid) such as nitric acid, sulfuric acid, etc. at a moderate or moderate degree. C-type phenolic resins, aromatic carboxylic acids, and their polyvalent metal salts have already been proposed and used.

Among these developers, the organic developer, the novolak type phenolic resin, the substituted salicylic acid, which is an aromatic carboxylic acid, and the acid (salt) are as follows. Thus it is applied to the support. That is, these acid compounds are naturally filled with synthetic mineral fine sand, hard glass fine particles, metal fine particles, etc. Water-based wet milling to give particles of 1 to 4 micron or less in sand mill, pigments such as clay, potassium carbonate, calcium carbonate, etc. Prepare a coating solution with a binder such as dextran, dextran, carboxymethyl acetylcellulose, or polyvinyl alcohol. Next, the developed coating solution obtained by applying the prepared coating solution to the sheet-shaped support has good smoothness, high color development degree, and excellent daylight resistance of the developed image. However, the color development speed is slow, and the color image is discolored when it comes into contact with plastics plastics or oils. The printability of the upper ink set, etc. is poor, and it is a synthetic product of Yuri Chemical. Therefore, it becomes a cost

On the other hand, the inorganic type developers have excellent printability such as ink-inking property and are inexpensive, so they are attractive as industrial materials, but the smoothness of the color developing system is poor. However, there is a drawback that stains (smudge) easily occur. One of the causes is that the particle size of the inorganic developer is large. Activated clay, which is a type of inorganic color developer, is described in Japanese Patent Publication No. 4 1-2 3 7 3

As described in No. 4 1 7 6 2 2 and Zhou 4 2 -88, acid clay or similar clays are treated with mineral acid to dissolve the acid-soluble clay. Aluminium, iron, sodium zinc, zinc, and other basic components were eluted, washed with water and dried, and the particle size of 10 S clones or less obtained with formula powder was 80 weight parts. Particles with a size of more than 1 centimeter and less than 1 micron are generally used with a particle size of about 15 weight percent or less.

In order to improve the coloring ability and smoothness compared to the conventional method, the particle size of the intimate-type developer should be adjusted so that the particle size of 5 micron or less becomes Ί 0 0 weight weight. However, the specific surface area is also increased to 200 m ^fc / 3, and at the same time, the viscosity at the time of preparing the coating solution increases and the amount of the binder must be increased. Since the blanket of the printing machine is dirty, it is not very viable.

In addition, adding a large amount of anti-dusting agent such as calcium stearate has little effect. Furthermore, if it is attempted to increase the smoothness by increasing the pressurization of the developed color with a machine calendar etc., the pulp fiber of the sea will be destroyed and the opacity will be lost. It was found that the whiteness deteriorates, the printing property such as ink imperfection deteriorates, and the commercial value greatly decreases.

Therefore, an object of the present invention is to provide a color-developing sheet for an image recording material which has improved smoothness, is free from stains (smudge), and is also excellent in printing suitability. It is in .

Disclosure of the invention

The above-mentioned purpose is to provide a color-forming sheet comprising an electron-accepting color developer, which can develop an electron-donating colorless dye, on the support, and an electron-donating colorless dye layer on the support. In a color-removing sheet for image recording material used in combination with a pigment, a coating containing an inorganic developer and acrylic latex as the developer layer described above. Achieved by using layers.

BEST MODE FOR CARRYING OUT THE INVENTION

Among the inorganic color developers used in the present invention, the color developer that is particularly recommended is proposed in Japanese Patent Laid-Open No. 5-7 — 1 5 9 9 6 and Zhou 5 8 — 1 6 8 8 5 It is a semi-synthetic solid acid obtained by the above-mentioned manufacturing method. This is a clay mineral having a layered structure consisting of silica tetrahedrons, with a S i 0 ₂ content of 8 2 to 9 6.5 weight parts by weight on a dry basis (10 5 dried at 3 o'clock straw). The acid treatment of the clay mineral is carried out to give a weight percentage of 85 to 95% by weight, and the clay mineral obtained is at least partially soluble in the medium in an aqueous medium. Acid and / or aluminum compounds to form hydroxides when these soluble compounds are other than hydroxides. Magnesium and Z in treated clay minerals Alternatively, it is called a semi-synthetic solid acid in Meisho, which is a new type of inorganic color developer produced by introducing an aluminum component and drying it as desired. And That is, this developer has a novel manufacturing method, and when the acid-treated clay ore is measured by X-ray diffraction or electron beam diffraction, it shows the silicic acid strength of the clay ore before acid treatment. It has a structure that does not substantially show a diffraction pattern based on a layered crystal composed of a tetrahedron. More specifically, the above-mentioned acid-treated clay minerals containing the above-mentioned magnesium and / or aluminum components were analyzed by electron beam diffraction to obtain a layered crystal composed of tetrahedral tetrahedrons. The diffraction pattern based on X-ray diffraction does not show the diffraction pattern based on the crystal of the above-mentioned hierarchal structure, and at least the case of elements other than oxygen is shown. Contains elemental and magnesium and / or aluminum.

Due to this semi-synthetic solid filter, the insufficient coloring density, which is the weak point of conventional clay mineral type developers represented by acid clay and activated clay, and the coloring image under high humidity can be obtained. It is possible to renew the decrease in concentration.

The present inventors have prepared a developer series by preparing a semi-synthetic solid acid, which is an inorganic developer and a new type of color developer manufactured as described above, into a coating liquid. When it is manufactured, the degree of color development is certainly high, and the deterioration of the degree of dryness of the color image under high humidity is improved, but on the other hand, the drawback is that the smoothness is not as good as that of conventional activated clay. It was found that stains (smudge) are likely to occur, and a wide range of semi-synthetic solid contacts, which are a type of slush-free developer, As a result of research, a semi-synthetic solid acid, which is a color developer, and an acrylic latex, which is a binder, are used as a developer layer for image recording material of the coating layer. We have found that the drawbacks of the above g can be solved by using only one, and have completed the present invention. The color development system of the present invention has high smoothness, has very little stain (smudge), has a high color density, and is free from deterioration of the color image under high humidity. In addition, the plasticized plastics for plastics and oils will not erase the colored image, and the surface strength (IGT big) of the upper color development sheet will be strong and excellent in printability. It is possible to obtain practically high quality products.

Acrylic latex, which is the binder used in the present invention, has recently had a film temperature (MFT) of +45 or less, and performance parameters such as smoothness and binding force. In order to achieve a good balance, a methyl methacrylate and / or a steel as a hard monomer component and a ethyl methacrylate as a soft monomer component are used. Copolymer, latex, butyl acrylate, 2-ethyl acetyl acrylate, or a copolymer type latex selected from the group consisting of 2 or more hexyl acrylate. It is

The acrylic latex used in the present invention generally has an irregular distribution in which each of the two types of monomer units has a small number of continuous irregularities. Copolymers, alternating copolymers in which each unit is regularly and alternately arranged, and each unit obtained by a special copolymerization technique have been retained for a long time. Co-copolymers, graft copolymers in which one type of monomer unit is continuous and one unit of another type of monomer is grafted, etc. Has a multi-layered structure that has been developed and developed in recent years (for example, a shell layer (shell) with a hard monomer, and a core (core) with a two-layer structure consisting of a fragile monomer). ), And in order to improve mechanical stability and binding property, acrylic acid, methacrylic acid, itaconic acid and maleic acid are included. Alternatively, a so-called soap free type, which is added with a small amount of its half-ester to modify with carpoxy, or has a small amount of emulsifier for water resistance and suppression of emission, is also used in the present invention. Even if the minimum film formation temperature (MFT) is controlled by adding a flexible agent and a film-forming rib agent, the desired effect of the present invention will not be impaired.

Here, the definition and measurement method of the minimum film-forming temperature will be explained.

When an acrylic latex aqueous dispersion forms a film film, the minimum temperature at which water evaporates and polymer molecules act on each other to form a film film is the minimum film formation temperature. (MFT) using a thermal gradient tester with an acrylic lattice on a metal plate with a temperature gradient (for example, from 1 to +95). The minimum temperature at which a dry film film is formed in an atmosphere excluding humidity after coating with a water dispersion (the temperature at which the film film becomes transparent and becomes the so-called minimum film formation temperature), and Obtain the whitening point temperature (temperature at which the film does not form and turns white).

In the present invention, the preferred amount of acrylic latex added is 100 parts by weight of inorganic developer in terms of solids by weight. 10 to 50 parts by weight. If it is less than 10 parts by weight, the smoothness cannot be improved, and if it is more than 50 parts by weight, the essential coloring ability is lowered, impairing the practical commercial value.

The present invention prepares a coating liquid containing an inorganic latex as a binder, a minimum film-forming temperature (FT) of +45, and the following acrylic latex, and -A major feature is that it coats the surface of the substrate with a coater and then dries it to give a color development sequence. According to experiments conducted by the present inventors, when the minimum film-forming temperature (MFT) becomes +45 or more of the acrylic system latex, the normal drying condition ( At a temperature of 10 5 to Ί 50, which is dried 3 seconds after application, the continuous film film is difficult to form and the film becomes white as described above, and the binding strength is greatly reduced. I knew it would. In addition, as a latex for a binder that is widely known and used widely, there is a styrene butadiene-based latex, but according to the experiments conducted by the present inventors, the styrene and the latex are used. The color density and the light fastness of the color image can be obtained depending on the ratio of the densities, the combined use of methyl methacrylate, or the modification of the force of the epoxy group and the change of the particle size, and the binding strength is sufficient. However, it has been found that the smoothness and dirt (smudge ') are insufficient.

On the other hand, the film film of acrylic latex is soft and further, the minimum film formation temperature (MFT) is set to +45 ° C or less. Film coating was completely formed under normal coater coating and drying conditions, and it had excellent smoothness, no smudge (smudge), excellent binding force, and was applied. Manifest The color density of the color sheet and the dazzling property of the color image are sufficient, and excellent printability is obtained.

In this invention, acrylic latex with a minimum film-forming temperature (MFT) of +45 or less was added to the inorganic dye, and it was not used as a coating liquid together with a dispersant, water retention agent, defoaming agent, etc. Apply it to a support such as paper using a coater method such as air knife, blade, roll, rubber dock, or curtain. Manufactures color-developing sheets for image recording materials.

In the present invention, water-soluble binders such as starch, polyvinyl alcohol, carboxymethyl cellulose, dextran, etc., as desired, clay, calcium carbonate, magnesium carbonate, sachinho It is also possible to add pigments such as white pigment, titanium oxide, zinc oxide, urea resin pigment, plastic bigmen pigment, tark, aluminum, and aluminum hydroxide to the coating liquid.

The non-sulfur dyes that are particularly recommended for use in the present invention are the semi-synthetic solid acid compounds described in the above-mentioned JP-A Nos. However, not only this but also other non-color-developing agents are colorless (□ □〉 The dye is adsorbed on the surface to develop color, which is used and the ratio per unit weight is used. The larger the surface area, the better the color development efficiency. That is, the smaller the particle size of the developer, the more advantageous. The present invention makes the particle size of the inorganic developer as small as possible to improve the color development efficiency. However, it is most effective when trying to achieve smoothness improvement by preparing a fluid coating liquid that does not gel.

Conventionally, the particle size of the colorless developer is 5 to 6 micron. Usually, a 5 to 6-micron mesh follow-up product was usually used, but according to the present invention, a 4-micron-cut product can be used. .5 It is a micro cutlet product and can be used to prepare coating solutions. The present invention will be further described below with reference to Reference Examples and the most typical examples. Reference Inversion The color-developing series used for the performance evaluation of the color-developing series obtained by carrying out the present invention [colorless (roico) dye-donative series, blue-developing] The manufacturing method of is described. All “parts” below represent parts by weight. 3.5 parts of a colorless dye, which is a colorless dye, is used as a high-boiling solvent, and 1 part of a black dye is used as a high-boiling solvent. It was dissolved in 100 parts of a dilute ruthenium-based organic solvent, and emulsified in acid-treated gelatin (isoelectric point 7.8) 1 0 parts of a 10-% aqueous solution of cesium. This emulsion was added to 150 parts of water in which 20 parts of Arabia gum were dissolved, and the pH of the solution was adjusted to pH 8.5 with caustic soda. The pH was kept at pH 4.4 with S acid for 10 hours, then cooled down to 21 and then added with 20 parts of 37% potassium aldehyde solution. , PH 10 with caustic soda, and a microphone mouth capsule. In the above-mentioned microcapsules of 100 parts (solid content), 1 part of 10 parts of polyvinyl chloride alcohol solution in water, 50 parts of wheat noodles

2

The amount of coating on the high-quality paper of 40

(Solid content) with an energy coater It was applied, dried, and used as the coloring sheet for blue coloring.

Fruit juice 1

Add 3.5 parts of 30% sodium potassium carbonate and 10 parts of 5% sodium nitrate sodium citrate to 180 parts of water, and mix. Semi-synthetic solid preparation (particle size: 3.5 micron cut) 1 0 0 parts was gradually added while stirring and dispersed, and then 10 parts of peroxidic oxidized water solution was added. Add 100 parts, stir, then mix with 50% polystyrene styrene latex (ratio is styrene butyl acrylate)-5 5 Z 4 5 Copolymer latex ♦ Minimum film formation temperature (MFT) + 20

40 parts was added to make a coating solution. Apply this coating solution to the fine quality canister of 40 3 Z m ^{2 with} an air coater so that the coating amount is 4.85 / m ² (solid content), and dry. It was developed.

Example 2

50% polystyrene acrylic latex of Example 1 (copolymer latex with a ratio of polystyrene / butyl acrylate = 55/545) ♦ The minimum film formation temperature (MFT) + 20 is set to 50% of the total volume of the metallic membrane and the acrylic latex (the ratio of the total volume of the metallic membrane is approximately 30%). Relay / 2-Ethyl relay Clear = 1 5/4 5

/ 40 Copolymer latex · Minimum film forming temperature (M F T)

+25) to obtain a coating solution in the same manner as the coating method except that the coating amount was 4.8 § / 2 (solid content) on the 40 3 Z m ² fine ash. Apply with an air coater. The cloth was dried and made to have a color development sequence.

Defeat 3

Add 30 parts of sodium persulfate (35 parts) and 5 parts of sodium persulfate (10 parts) to 3.5 parts of water. , 100 parts of semi-synthetic solid acid (particle size: 3.5 micron cut water) was added gradually with stirring, and dispersed, and then 10 parts of peroxidic aqueous solution of propylene oxide was added. Add 100 parts and mix thoroughly. 4 3% Percent methyl methacrylate acrylic latex (ratio is methyl methacrylate% (shell layer) / Two-layer structure latex with a core acrylic core (core) = 1 5/8 5 * minimum film formation degree (MFT) + 3 7) 4 Add 6.5 parts Stirring coating solution This coating solution is applied to a high quality paper of 40 3 / πι ^{2 so} that the coating amount is 4.8? / M "(solid content)". It was applied with a tar and dried to give a color-developing series.

Water 30% in 24.5 parts 3.5% sodium citrate sodium 3 parts and 5% sodium sodium pyrophosphate 0 parts 0 and 10 parts -Add 300 parts of hexane-oxidized damp water solution and stir to add 100 parts of semi-synthetic solid acid (particle size 3.5 micron cut) to the mixture gradually with stirring. , Was dispersed and used as a coating liquid. The amount of this coating solution applied to the fine ash of 40 ^ / m ² was 4.8? / m ² (solid content), coated with an air coater, dried, and made into a developer sheet. '

Comparative example 2

Comparative Example Ί 10% Percent Oxidized Damp Aqueous solution Paces Polyvinyl alcohol (PVA, degree of saponification 98.5 morphase / degree of polymerization, degree of polymerization 500) Other than replacing with aqueous solution 3 no 2

So that the coated ^ ϊ fish will be 4.8 Sf / 7H ² (solid content) on the high quality canister-Applied with an air-nay coater, dried and developed as a comparative color Comparative Example 3

30 parts of 30% sodium carbonate sodium salt and 3.5 parts of 5% sodium chloride sodium phosphate were added to 180 parts of water, stirred, and a semi-synthetic solid was added.截 (particle size 3.5 micron cuts) 100 parts slowly added with stirring. • After dispersion, 10 parts. Add, stir and further add 50% styrene styrene butadiene latex (ratio is methyl methacrylate styrene styrene butadiene = 1 0/5 5/35 5 copolymer latex * The minimum coating temperature (MFT) + 5) (40 parts) was added, and the coating liquid was stirred and used as the coating liquid. The coating amount was 4.8? / m ² (solid content) coated with air knife coater

Comparison i¾ 4

Comparing 3 to 50 percent polyethylene styrene diene latex (ratio is methyl methacrylic steel styrene diethylene butadiene = 1 0/5 5 5/3 5 copolymer latex Membrane temperature (MFT) + 5) of 50% polystyrene styrene acrylate (ratio of styrene Z butyl acrylate-7 5/15 copolymer latex) X Minimum film forming temperature (MFT) + 59, except that the same amount was replaced with), the coating liquid was prepared in the same manner as Zhou's method, and the coating amount was 4.8 S Zm ² (solid content) on 40 3 / m ² fine paper Thus, it was applied with an air knife coater and dried to give a color-developing series. Comparison 5

Comparing 3 to 50 percent polystyrene butene diene latex (ratio of methyl methacrylate / styrene / ptadiene = 10/5/5/5/35 copolymer latex Minimum film formation temperature (MFT + 5) is set to 50% Permeable metal lattice acrylic lattice (ratio is methyl methacrylate) (shell employment) / Ethyl acrylateー卜 (core)-50/50 0 2 hiring structure latex ♦ Minimum film formation temperature (MFT) + 7

The coating amount on the quality羝of but substituting peripheral weight as coating solution in the same manner 4 0 / m ² to 3 Te) is 4.8? / m ² (solid content), applied with an air knife coater, dried and made into a developer series. Test method The color development sequence obtained as described above was tested and measured by the following method.

0 Color density The color development system was combined with the above color development system, and the color was developed through a force renderer, and the following values were measured with a color difference meter. The smaller the value, the higher the color density.

Reflection rate of coloring part

Color density (percent)-X 100 (%) Reflectance of blank area o Smoothness Measured with a Beck smoothness tester. The larger the value, the higher the smoothness.

0 Stain (colored stain due to smudge friction) A sample was put on the surface and rubbed against the above-mentioned color-developing sheet to determine the following value with a color-difference meter. The larger the threshold value, the less the dirt.

Dirt reflectance

Dirt (percent) = X 100 (%) Reflectance of blank area

0 Surface strength (printability test)

The strength when measured using an IGT tester is 5, 4,

3, 2, and Ί. (5… Strong, Ί… Weak) Test results

Table 1 shows the characteristics of the color development system.

Table 1

* This M FT value is the value of the copolymer latex outside the present invention,

As is clear from Table 1, by producing a developing chain containing semi-synthetic solid acid and acrylic latex as a binder, It is excellent in smoothness, has a small amount of smear (smudge), has a good surface strength, and has a high degree of color development S. It is possible to obtain a color sequence for image recording materials. I understand.

Claims

The scope of the claims

1. Used in combination with a coloring sheet which has an electron-accepting developer layer capable of developing an electron-donating colorless dye on the support and an electron-donating colorless dye layer on the support. In the color developing system of the image recording material, the developer for image recording material is characterized in that the developer employs an inorganic colorant and an acrylic latex. Color scheme.

2.The inorganic dye is derived from a clay mineral having a layered structure consisting of silica tetrahedron, and the Although it shows a diffraction pattern based on the crystal of the layered structure of the body, it does not show a diffraction pattern based on the crystal of the above-mentioned structure by X-ray diffraction, and other than oxygen. The color developing system for image recording materials according to item 1 of the scope of the search, which is a color developing agent containing at least the element silicon, magnesium, and / or aluminum as the element.

3. The color developing system for image recording materials according to claim 1, wherein the acrylic latex has a minimum film forming temperature (M F T) of +45 or less.

4. The particle size of the non-staining color developer is 4 micron or

3.5 The developer for image recording material according to claim 1 of the claim, which is a micro-cut.