JPS5973988A - Recording material - Google Patents

Abstract

PURPOSE:To provide a non-carbon pressure sensitive recording material excellent in a color forming speed, color density, the fading resistance of a color image and the stability of a white background, obtained by containing a polystyrene adsorbed inorg. solid acid as a coupler in combination with an electron donating colorless dye. CONSTITUTION:An electron donating colorless dye (e.g., Crystal Violet lactone) and a polystyrene adsorbed inorg. solid acid as an electron accepting coupler are combined to obtain an objective recording material. In this case, the inorg. solid acid is pref. a semi-synthetic solid acid obtained by a method wherein a clay mineral having a laminar structure comprising a silica tetrahedron is subjected to acid treatment so as to adjust SiO2 content to 82-96.5wt% under drying reference (at 115 deg.C for 3hr) and, in an aqueous medium, the obtained clay mineral is contacted with an Mg and/or Al compound at least partially soluble in said medium and, according to circumference, the mixture is neutralized to form hydroxide to introduce Mg- and Al-components into the clay mineral. Polystyrene is adsorbed by the resulting solid acid in an amount of 0.3-20wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel recording material, and more specifically, a layered structure consisting of an electron-donating colorless dye and a regular tetrahedron of activated clay or silica represented by acid clay, activated clay, etc. 5i on dry basis (dried at 105°C for 8 hours)
acid treatment to give an n2 content of 82 to 965 wt. When the compound is other than a hydroxide, magnesium and/or aluminum are introduced into the acid-treated clay mineral by neutralization with an alkali or acid so that a hydroxide is formed, and optionally by drying. The present invention relates to a recording material particularly improved in image fastness using a color developer in which polystyrene is adsorbed to an inorganic solid acid such as a manufactured semi-synthetic solid acid.

Recording materials consisting of colorless (leuco) dyes and solid acids are well known, for example U.S. Pat. No. 2,505,470;
(No. 15489, No. 2550471, No. 25483
6 (No. i, No. 2712507, No. 2730456,
No. 2730457, No. 3418250, and substances that have electronic potency, color reactivity with colorless dyes, and adsorption properties (hereinafter referred to as color developer) as described in the specifications, etc. Carbonless pressure-sensitive recording materials, which are image recording materials that utilize the color reaction caused by contact between the two, have the oldest history and are the largest in production. There are other types of recording materials, such as heat-sensitive recording materials, heat-sublimable colorless (leuco) dyeing and thermochromic image recording materials (for example, Lisu 1 Kaisho 52
-1491.23 Publication,! (Japanese Agency Publication No. 54-53538, etc.).

Therefore, the present invention extends to all image recording materials that utilize this coloring principle.

In the present application, in order to make it easier to understand, the effects of the present invention on a color developing sheet of a carbonless pressure-sensitive recording material will be explained in detail, but as mentioned above, the present invention is not limited to this.

Carbonless pressure-sensitive recording materials typically consist of a colorless (leuco) dye donor sheet and a color developer sheet, where the colorless (leuco) dye can be dissolved in a high-boiling solvent and incorporated into microcapsules. many.

Conventionally, microencapsulation methods have been carried out by coacervation method, in situ method, interfacial polymerization method, etc. phenyl)nacclide, 3-(p-,;methylaminophenyl)-3-(2-methylindol-3-yl)-
Triallylmethane phthalide such as 6-dimethylaminophthalide and acyl derivatives such as benzoyl, anizoyl, and piparoyl of methylene blue; 8-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-7- There are xanthine phthalide-based dyes such as dibenzylaminofluorane and leuco dyes, which are also used in the present invention.

High boiling point solvents often used in carbonless pressure-sensitive recording materials include alkylnaphthalenes represented by diisozolobylnaphthalene, diallylalkyls represented by -phenyl-1-xylylethane, and alkyl biphenyls represented by isopropylbiphenyl. and others, triallyl dimethanes, alkylbenzenes, penzylnaphthalenes, sialylalkylenes, allylindane sea urchins [1
Aromatic hydrocarbons such as; carboxylic acid ester compounds such as butyl phthalate and dioctyl maleate; phosphoric acid ester compounds such as tricresyl phosphate; natural products such as castor oil, soybean oil, and cottonseed oil. Animal and vegetable fats and oils or modified products thereof; high-boiling fractions of natural products such as mineral oil (such as aliphatic hydrocarbons), etc.

Electron-accepting color developers are inorganic solid acid-based color developers that are made by lightly or moderately treating acid clay, natural clay minerals such as atano ξrugite clay, and acid clay, which is a montmorillonite clay mineral, with mineral acids. activated clay; As organic color developers, various phenolic compounds, Nozerac-type phenolic resins, polyvalent metal salts of aromatic carboxylic acids, etc. have already been proposed, but the clay mineral-based inorganic solid acid color developer mentioned above is not suitable for color development. The image stability is poor (the color easily fades due to sunlight, etc., and the color fades due to moisture from water or steam), and the coloring ability decreases due to adsorption of substances in the air (the shelf life of the product is short). ), and the color development speed of all multi-color developers is slow, and the single-color image fades when it comes in contact with plasticizers or oils.

The color developer recommended for use in the recording material of the present invention is an inorganic solid acid for reasons such as the thermal stability of the color developer sheet. Semi-synthetic solid acids, which are manufactured using a similar manufacturing method, are preferred because they have excellent color developing ability.

This is a clay mineral having a layered structure consisting of regular tetrahedrons of silica.On a completely dry basis (drying at 105°C for 3 hours), the 8102 content is preferably 82 to 965% by weight, preferably 85 to 9%.
5 wt.ξ-cents and the resulting clay mineral is contacted in an aqueous medium with a compound of magnesium and/or aluminum that is at least partially soluble in said medium, and the soluble compound is In the case of other than hydroxides, magnesium and/or aluminum components are introduced into the acid-treated clay mineral by washing with alkali or acid to form hydroxides, and then drying to a desired degree. This is a new type of inorganic solid acid produced.

[In the present invention, this will be referred to as a ``semi-synthetic solid acid.'' That is, the manufacturing method is also new, and the solid acid has a structure that does not exist in nature.

This ``semi-synthetic solid acid'' has excellent properties not found in conventional inorganic color developers, such as improved coloring ability for electron-donating colorless dyes, no decrease in color density under high humidity, and little change over time. Brought to you.

In other words, Tekiru can be seen as a new type of color developer that more than compensates for the weaknesses of conventional clay mineral color developers such as activated clay.

Here we present an inorganic solid acid, in particular a new type of ii? The suitability of the "semi-synthetic solid acid", which is a DfQ agent, for 19 types of recording materials was evaluated through various tests, and it was found that the color development ability was certainly improved, the luminosity of the color density under high humidity, and the decay over time was small. was confirmed, and there was a clear difference from conventional clay mineral color developers such as activated clay produced in Japan, but on the other hand, the same drawbacks were observed even with conventional activated clay. However, it was discovered that the colored images were subject to severe discoloration and fading due to sunlight and other light.

26-di-tert-butyl-P has been known and used as a substance that prevents discoloration and fading of colored images in recording materials due to light.
-cresol, 22'-methylenebis(4-methyl-6
-tertiary dithylphenol), 1.1.3-tris(2-
Methyl-4-hydroxy-5-isobutylphenol)
Phenol-based such as butane; Sulfur-based such as dilauryl thiodipropionate; Triisodecyl phosphor L,
Phosphorous antioxidants such as diphenylisodecyl phosphite, phenyl salicylate, salicylic acid type of tertiary rutylphenol; benzophenone type such as 2-hydroxy-methoxybenzophenone; 2-( Ultraviolet light consisting of benzotriazole systems such as 2'-hydroxy-5'-methylphenyl)benzotriazole; nitrile systems such as ethyl-1-phenylbenzylidene cyanoacetate and 2-ethylhexyl-1-phenylben cylidene dianoacetate. Adding absorbent etc. 1. However, it has almost no effect on the recording material of the present invention, and in JP-A No. 48-33209, acid clay as a color developer and nitrile phenylphenol or l), [1/- Although an example is described in which isoglopylidene diphenol is used in combination, according to the experiments of the present inventors, ξ-ra phenylphenol as well as P, I)
Even '-isopropylidene diphenol is mixed with an inorganic solid acid to produce a color developing sheet. It was found that there was severe yellowing of the white background due to the NOx exposure test (confirmed in the NOx exposure test), and that it was of no practical value.

Furthermore, Japanese Patent Publication No. 50-1696'9 also describes an example in which ortho- or ξ-hydroxybenzoic acid alkyl ester and activated clay are coated on a support as a color developing sheet for Norker Hson recording materials. However, according to experiments conducted by the present inventors, orthohydroxybenzoic acid alkyl esters are generally liquid at room temperature and are strong! However, the present inventors sought a substance that is effective in preventing discoloration and fading of colored images caused by light and oxidizing gases in recording materials using inorganic solid acids 1.1. After conducting extensive research,
By using polystyrene adsorbed to an inorganic solid acid as a color developer, it is possible to prevent discoloration and fading caused by sunlight and other oxidizing gases such as nitrogen oxides in the air. The present invention was made based on the novel finding that there is a recording material which exhibits a remarkable effect and does not cause any yellowing of the white background portion, and which is practically excellent and does not use any solid acid.

An example of using polystyrene in a carbonless pressure-sensitive recording material is a publication regarding a colorless dye sheet, but JP-A-48-74811 discloses an organic solvent containing polystyrene (polystyrene and a colorless (leuco) dye). By using microcapsules encapsulating organic solvents (mixed and dissolved), it is easier to emulsify during encapsulation, and by increasing the viscosity and surface tension of the organic solvent, it is effective in preventing the solvent from seeping out from the microcapsules. It is stated that. Furthermore, JP-A No. 57-125090 discloses a method in which microcapsules containing an organic solvent containing styrene oligomer (styrene oligomer and colorless (leuco) dye are mixed and dissolved) are coated on a support such as paper. sunlight of the coloring agent [colorless (leuco) dye] in the support layer;
It is stated that it prevents arcuate damage caused by heat.

However, according to the experiments conducted by the present inventors (C), coloring was achieved by combining an old sheet coated with styrene-containing microcapsules of oligomers and/or polymers in the above-mentioned publication with an old sheet dyed with a pond color and a sheet with an inorganic solid acid. Discoloration and fading of the image due to sunlight and oxidizing gas (d, no improvement was observed).

On the other hand 1. tIJ Sesame and/or polymer styrene is mixed in a color developer sheet to make S heavy use. Microcapsules encapsulating a solution in which only oligomer and/or polymer styrene is dissolved in an organic solvent are mixed with an inorganic solid acid. A method of coating on a support such as paper. Another possible method is to disperse oligomer and/or polymer styrene in water, pulverize it in a ball mill, etc., and then mix it with a solid acid and apply it to a support such as paper, but according to experiments conducted by the present inventors, coloring It is not effective in preventing discoloration and fading of images.

However, when oligomeric and/or polymeric styrene is adsorbed onto an inorganic solid acid as in the present invention, it can be prepared by completely dissolving polystyrene in an organic solvent, adding the inorganic solid acid therein, stirring well, and then drying. It was found that it was effective in preventing discoloration and fading only when the inorganic solid acid adsorbed on polystyrene was used as a color preservative.

Examples of inorganic solid acids that can be effective by adsorbing styrene in oligomers and/or d and polymers of the present invention include athanolugite clay, acid clay, activated clay, and bentonite.
A semi-synthetic solid acid is a semi-synthetic solid acid, but a commercially available and highly slippery Ri coloring agent that exhibits a remarkable effect on 71 moles is a semi-synthetic solid acid.

The merigomeric and/or polymeric styrene suitable for use in the present invention has an average molecular weight of 800 to 400. (10
0, preferably 500 to 200.00
It is 0. If the average molecular weight is less than 300, it will be liquid at room temperature and have a peculiar odor, requiring careful handling, resulting in poor workability.If it is more than 400,000, it will have a very high viscosity when dissolved in an organic solvent, making it difficult to handle.

The polystyrene adsorption M of the present invention is preferably an inorganic solid acid 1
The amount is from 01 to 30 parts by weight, particularly preferably from 3 to 20 parts by weight. If the amount is less than 11 parts by weight of O, no effect will be obtained, and if it is more than 30 parts by weight, the color development will be adversely affected and the color density will be low, making it impractical.

Solvents that dissolve the polystyrene used in the present invention include acetone, methyl ethyl ketone, oxane, chlorinated hydrocarbons, ethyl acetate, benzene, toluene, and xylene.

Here, a specific example of the method of adsorbing polystyrene onto an inorganic solid acid according to the present invention will be explained in detail.

(The following "1 part" all represent "heavy part") Example: Regarding the production method of 5 parts of polystyrene adsorption semi-synthetic solid acid, put 8 oome of toluene in a container for 2β and make the average molecular weight 5,'O o O. After adding 5 parts of polystyrene and completely dissolving it, 10 parts of ``semi-synthetic solid acid'' is gradually added with stirring and dispersed in the polystyrene-dissolved toluene.Next, ``semi-synthetic solid acid'' The container in which the toluene is dispersed is milled and zeta-borated under reduced pressure on a hot water bath to a size that can completely remove the toluene.After the toluene is completely removed, the semi-synthetic solid acid adsorbed on polystyrene is crushed into particles using a dry pulverizer. It is crushed to a diameter of 5 μm or less and used as a color developer for recording materials.

l J's polystyrene adsorption semi-synthetic solid acid dispersants and their additives (e.g. anti-dusting agents, water retention agents, etc.), starch, polyvinyl alcohol, carboxymethyl cellulose, white water-soluble binders such as dextrin; emulsion binders such as styrene-based latex, acrylic latex, and vinyl acetate-based latex;
Color developer sheets for recording materials are manufactured by coating and drying onto a support such as a plastic film, laminated paper, or synthetic paper using a coater such as an air knife, blade, low-pressure doctor, or curtain.

As mentioned above, even if polystyrene is added in the form of powder to the color developing layer of a recording material that uses an inorganic solid acid as a color developer, no effect is seen in improving image fastness. The effect can be clearly seen when polystyrene is adsorbed onto an inorganic solid acid. The most reliable method for this adsorption is to dissolve polystyrene in an organic solvent, add solid sulfur to the solution, and distill off the solvent, but other methods may also be used.

The polystyrene used here may be so-called oligostyrene, which is a styrene polymer in a broad sense.

Polystyrene-adsorbed inorganic solid acid 6'' - It goes without saying that the inorganic solid acid must be pulverized to a particle size suitable for use in coating liquids or coating layers.

In the present invention, if desired, clay, kaolin, magnesium carbonate, magnesium oxide, zatin white, titanium oxide, zinc oxide, urea resin pigment, plastic pigment,
Pigments such as talc, alumina, aluminum hydroxide, etc. may be added to the coating.

Next, let us discuss the method of manufacturing the coloring (agent) sheet (colorless (leuco) dye donor sheet) used in the examples of the present invention.

Colorless (leuco) dye Crystal ζ ioolenotolactone 3 parts, penzoyl leucomedylene pur-1,5i
'15 1 part of malachite green lactone is mixed with 100 parts of diarylethane organic solvent, which is a high boiling point solvent, and acid-treated gelatin (isoelectric point 7.8) 10) E-cent aqueous solution 1
It was emulsified to 60 parts.

Add this emulsion to a solution prepared by diluting 20 parts of gum arabic in 10 parts of water, and add 8 parts of Ptl with caustic soda.
Keeping the liquid temperature of 5 and O'C, Pll is 4.4 with acetic acid.
The mixture was cooled to 10°C, and a total of 20 parts of 37) ξ-cent formalin aqueous solution was added thereto, stirring continued for 24 hours, and the pH was adjusted to IO with caustic soda to form microcapsules.

Add 100 parts of the above microcapsules (solid content), 50 parts of a 10% polyvinyl alcohol aqueous solution, and 780 parts of wheat densi. It was coated with an air knife coater to form a coloring (agent) sheet.

``2'' is a coacervation method using a combination of gelatin and a polymeric anion, but the microcapsule manufacturing method used in that song is an in-situ method using urea-formaldehyde or melamine-formaldehyde polycondensation reaction, and an active method. There are known microencapsulation methods such as an interfacial blowing method that utilizes an interfacial reaction between a hydrogen compound and an isocyanate compound, but the present invention is not particularly limited to this method, and microencapsulation is not required.

In the present invention, as described above, a color developing sheet using a color developer adsorbed on a semi-synthetic solid acidic acid containing oricomer and/or polymer sugoleum and, for example, the above-mentioned color forming agent.
By combining sheets (colorless dye sheets), you can improve coloring speed, coloring density, fading resistance of colored images (light resistance, water/moisture resistance, plasticizer resistance, secondary oxidizing gas properties, etc.), and white background stability. We have succeeded in providing a carzene-free pressure-sensitive recording material that has significantly improved properties such as (persistence of coloring ability, yellowing resistance), etc. (Of course, the effects for other recording months are also comparable.) In particular, improvements in color development speed, color development density, color development under high humidity, 7i'' (duration), and nitrogen oxide gas resistance of color images are improved. The improvement and reduction of photobleaching and no yellowing of white backgrounds are noteworthy.

Hereinafter, preferred embodiments of the present invention will be specifically explained using the most representative examples. I will clarify.

Example 1 Put 811 (l me) of methyl ethyl ketone into a 21 container, add 75 parts of polystyrene (5 (+ (l)) and dissolve completely, and then gradually add 100 parts of "semi-synthetic solid acid" with JIV stirring. In addition, it is dispersed in polystyrene-prepared 5th edition methyl ethyl ketone.Next, the methyl ethyl ketone is completely removed by heating the container in which the ``semi-synthetic solid acid'' is dispersed, and then the ``polystyrene-adsorbed semi-synthetic solid acid'' is dispersed. It was pulverized using a dry pulverizer so that the particle size was 5 μm or less.

After dissolving 05 parts of sodium hexametaphosphate in 60 parts of water, the above "polystyrene adsorption semi-synthetic solid acid"'50
Part'ff: *: After gradually adding and dispersing while stirring,
50 parts of a 10% denzone oxide aqueous solution and 10 parts of 48% styrene-butadiene latex were added and dispersed, and adjusted to [email protected] with caustic soda to prepare a coating liquid. Apply this coating liquid to 40-shoulder high-quality paper.■ is 5-gA?
(solid content) using an air knife coater to form a color developing sheet.

Example 2 A color developing sheet was prepared in the same manner as in Example 1 except that polystyrene with an average molecular weight of 40.00 was replaced with polystyrene with an average molecular weight of 40.00 and methyl ethyl ketone was replaced with toluene.

Comparative Example 1 After completely dissolving 0.5 parts of sodium hexametaphosphate in 60 parts of water, 5.0 parts of semi-synthetic solid acid U was gradually added and dispersed with stirring, and 50 parts of 10-ξ-cent oxidized starch aqueous solution, Add 0 parts of 48.ξ-cent styrene butadiene latex, disperse, and adjust the pH to 85 with caustic soda to form a coating solution. Add this tt liquid to 4.
Is the coating amount 5 g/AI on 0 mm high quality paper? (solid content) using an air knife coater to form a color developing sheet.

Comparative Example 2 Average molecule @: 5 + 1 (15 parts of polystyrene of 1 liter is dissolved in a high boiling point diarylmethane organic solvent 1)
1111? microcapsules by dissolving in 11 and coacervation method by combining gelatin and polymeric anion as described above.

After adding 05 parts of sodium chloride metaphosphate to 60 parts of water and bringing it up to 111'l',
? B k J7) Gradually add and disperse the above polystyrene-encapsulated microcapsules (30 parts (solid content)) while stirring.
Add and stir for 41 minutes, add and disperse 50 parts of lO no ξ-cent oxide de7so7 aqueous solution and 10 parts of 48 no ξ-cent styrene butadiene latex, and then add caustic soda 't' pHf B, r). Coating liquid and L7.

Apply this coating liquid to 40 g/rrl high-quality paper at a coating amount of 5 pats (
Air knife coater so that solid content)! Apply,
It was made into a color developing sheet.

Comparative example 3 40 cent polystyrene dispersion was ground for 2 days in a dill mill.

After adding 0.5 parts of sodium hexametaphosphate to 60 parts of water and dissolving it, 50 parts of a semi-synthetic solid acid was gradually added and dispersed with stirring. [Add 10 parts and stir, lO]
After adding and dispersing 50 parts of an aqueous denzone oxide solution and 10 parts of 48-free styrene-butadiene latex, a coating liquid was prepared with caustic soda-t-1t of 8.5.

This coating solution Q40 was manually coated on high-quality paper using an air knife coater so that the coating amount was 5W (solid content) to form a color developer sheet.

Test method L: The color developing sheet obtained as in T'+ was tested and measured in the following manner.

・Color development 6' degree The color development sheet was combined with the above-mentioned colorless dye sheet (color development (agent) sheet), and the color development sheet was colored by passing it through a calendar under the pressure of 96 degrees. Total (
The reflectance ()ξ-cen))e was measured using a color difference meter (hereinafter referred to as a color difference meter), and the following values were obtained.

(Reflectance 1 hour after passing through a calendar) - Sunlight resistance of colored image The developed sheet, which was colored through a calendar together with the above-mentioned colorless dye sheet (coloring (agent) sheet), was exposed to direct sunlight for 1 hour. Then, measure the residual density using a color difference meter as the reflectance ().
Cent) was measured and the following values were obtained.

・Moisture resistance of colored image The color developing sheet developed through the above-mentioned calendar was
The humidity was controlled in a constant temperature and humidity chamber of 'C95 Nozo-Sent RII for 4 days, and the residual temperature was measured using a color difference meter f reflectance, and the following values were determined.

- Resistance to oxidation ♀ elemental gas (NOx gas) 50% of the color developing sheet developed through the calendar described above
It was exposed to 0 ppm NOx gas for 10 minutes, and its residual concentration was measured by reflectance using a colorimeter, and the following values were determined.

- Sunlight-resistant white background area (non-image area) The white background area of the color developing sheet was exposed to direct sunlight for 8 hours, and its reflectance was measured using a blue filter of a color difference meter.

- Nitrogen oxidation gas (NOxf7) resistance of the white background area The white background area of the color developing sheet was exposed to QNOx gas 1000pr+vn for 30 minutes, and its reflectance was measured using a blue filter of a color difference meter.

Measurement result Table 1 shows the fast fading properties of the colored images.

The values below are percentages of reflectance, and the smaller the number, the more 6
Indicates that the degree of compatibility is high.

Tables 1 and 2 show the yellowing resistance of the white background (chromaticity after the test). The values below include reflectance T with a blue filter,
The larger the value, the more yellowing the color is.

Table 2 As shown in Tables 1 and 2 above, when a semi-synthetic solid acid with a polymeric styrene adsorbed is used as a color developer for a color developer sheet using an inorganic solid acid, the sunlight resistance and moisture resistance of the colored image The present invention is a practical product that is excellent as a whitening agent for recording materials because it has excellent oxidation properties and nitrogen oxide gas resistance (oxidation gas resistance), and there is no yellowing of the white background due to sunlight or nitrogen oxide gas. It has come to provide some illusions.

Claims (1)

[Claims] l) A recording material comprising a combination of an electron-donating colorless dye and an electron-accepting color developer that develops color when it comes into contact with the colorless dye, wherein the color developer is an inorganic solid acid adsorbed on polystyrene. Recording material characterized by: 2) An inorganic solid acid is used to dry clay minerals with a layered structure consisting of silica tetrahedrons on a dry basis (dry at 105°G for 3 hours)
The clay mineral obtained is treated with acid to give a 5i02 content of 82 to 96.5 wt. If the soluble compound is other than a hydroxide, the magnesium and/or aluminum component is introduced into the nucleic acid-treated clay mineral by neutralizing it with an alkali or acid so that a hydroxide is formed. A recording material according to claim 1, which is a semi-synthetic solid acid produced by drying.