JPS606795B2 - pressure sensitive recording sheet - Google Patents

Description

[Detailed description of the invention] The present invention relates to a pressure-sensitive recording sheet.

More specifically, it relates to a pressure-sensitive recording sheet containing a color-forming agent that forms a colored image by contacting or reacting with a color-developing agent, particularly a pressure-sensitive recording sheet that has excellent light fastness, water resistance, and sublimation resistance after color development. Regarding improvements. A nearly colorless organic compound (hereinafter referred to as a color former) and an adsorbed or reactive compound (hereinafter referred to as a head color agent) that develops a color upon contact with this color former, such as acid clay, activated clay, Ata/V regiite. Recording sheets that utilize coloring reactions with viscous substances such as zeolite, bentonite, and olefin, organic acids such as succinic acid, tannic acid, gallic acid, and phenolic compounds, and acidic polymers such as phenol formaldehyde resin are generally well known. It is being
Here, the color former is a substance that generates color by donating electrons or accepting protons such as acids, and the color developer is a substance that accepts electrons or donates protons.

Recording sheets that specifically utilize this phenomenon include pressure-sensitive copying paper (for example, U.S. Pat. Nos. 2,505,470 and 25,054)
No. 89, No. 2550471, No. 2548366, No. 2712507, No. 2730456, No. 27304
57, No. 341825), and thermal recording paper (for example, Japanese Patent Publication No. 43-416, U.S. Patent No. 2939009)
) etc.

Furthermore, a printing method is also known in which a colored image is obtained by supplying ink containing a color developer through a medium such as a stencil onto a sheet coated with a color developer (German patent application (O
LS) No. 1939624). In order to utilize the above phenomenon, pressure, heat, and other physical conditions from a vent, typewriter, etc. are required. The most typical form of recording sheet is a pressure-sensitive recording sheet.

Pressure-sensitive recording sheets are produced by dissolving a coloring agent in a solvent such as alkylated naphthalene, alkylated diphenyl, or alkylated diphenylmethane, dispersing it in a binder or incorporating it into microcapsules, and then producing paper, plastic sheets, etc. It is obtained by coating a support such as resin-coated paper. On the other hand, the pigment and the binder are dissolved or dispersed in a medium such as water and applied to the support.

Generally, the color former and developer are applied to the same or opposite or different sides of the support.

Although the above-mentioned pressure-sensitive recording sheet has several advantages, there are also some points that should be improved. For example, pressure-sensitive copying paper that develops a blue color does not have sunlight fastness as a conventional coloring agent, but crystal violet lactone (hereinafter referred to as the primary coloring agent), which has an instantaneous coloring property, and crystal violet lactone (hereinafter referred to as the primary coloring agent), which has a delayed coloring property, has no sunlight fastness. Penzoyl leucomethylene flue (hereinafter referred to as the secondary coloring agent), which has a high degree of strength, is used in combination to compensate for the weak points of each other during color development, but as time passes, the color image becomes worse than the primary coloring agent. It is inevitable that the color will disappear and turn green due to sunlight.

Since such a phenomenon has a significant effect on commercial value, improvements are desired. Other drawbacks that need to be improved include the water resistance of colored images and color stains due to sublimation of color formers.

Therefore, the purpose of the present invention is ``first, to improve light resistance, second, to improve water resistance, third, to improve color staining due to sublimation of color former, and fourth, to achieve the above objectives. The object of the present invention is to produce a pressure-sensitive copying sheet with the following properties.The above object of the present invention is achieved by using a novel compound represented by the general formula (1) as a coloring agent.

(In the formula, R is a lower alkyl group, and R2 is a hydrogen atom or a lower alkyl group.

) Furthermore, the color forming agent of general formula (1) can be used in combination with a known color forming agent to obtain a pressure-sensitive recording sheet that develops an arbitrary color.

The general formula (1) used in the pressure-sensitive recording sheet of the present invention
The compound represented by the following general formula (oa) (in the formula R.
and R2 have the same meanings as defined in general formula (1), and Z is an anionic residue.

) or the triphenylmethane dye represented by the following general formula (wherein R and R2 have the same meanings as defined in general formula (1)).

) and 1.0 to 2.5 moles of triphenyl phosphite were mixed at 30 to 1300C in a solvent such as chloroform, dichloroethane, tetrachloroethane, or toluene-xylene. ~1
After immediate reaction, the reaction solution is cooled, thoroughly washed with water, and the solvent is evaporated. A basic compound such as triethylamine, tributylamine, or pyridine may be used during the heating reaction, or an acid or alkali (eg, sodium hydroxide) aqueous solution may be used during water washing.

Further, if necessary, purification may be performed by recrystallization using a solvent such as alcohol or ligroin.

The color forming agent of the present invention obtained as described above is dissolved in a solvent and encapsulated, or dispersed in a binder solution and applied to a support.

As a solvent, natural or synthetic oils can be used alone or in combination.

Examples of solvents include cottonseed oil, kerosene, paraffins, naphthenic oils, alkylated biphenyls, alkylated Tafels, chlorinated paraffins, alkylated naphthalenes, and the like. Methods for manufacturing capsules include methods using coacervation of hydrophilic colloid sol described in U.S. Pat. No. 2,800,457 and U.S. Pat.
There are interfacial polymerization methods such as those described in No. 9264 and No. 1091076. A binder can also be used in conjunction with the preparation of the color former-containing capsule coating solution.

Binders used in combination include water-soluble binders such as proteins (e.g., gelatin, albumin, casein, etc.), cellulose (e.g., carboxymethyl cellulose, hydroxyethyl cellulose, etc.), succalose (e.g., agar, sodium alginate, carboxymethyl starch, gum arabic, etc.). Water-soluble synthetic polymer compounds such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, styrene-butadiene-rubber latex (SBR latex), acrylic ester latex, vinyl acetate latex, etc. latexes are used.

In this case, a resin powder or an inorganic pigment such as talc or zinc oxide may be added to the coating liquid in order to improve the surface properties of the coated surface.

Further, the coating method may be a method used by those skilled in the art, such as an air knife coater, a roll coater, a blade coater, a size press coater, or the like.

Next, the color developer that contacts or reacts with the color former of the present invention is not particularly limited, but includes clays, phenol resins, metal salts of aromatic carboxylic acids, and the like.

Clays include acid clay, activated clay, attapulgide, kaolin, and the like. Among these, clays with a three-layer structure, such as acid clay and activated clay, have high complexion ability.
The present invention has great effects. Other clays are also effective, but their head color ability is lower than those with a three-layer structure, such as acid clay and activated clay. Phenolic resins are proton releasing phenolic resins that are generally known in the art.

Specifically, they are phenolic aldehyde polymers (so-called nopolak type) and phenolic acetylene polymers.
Examples of these compounds include p-phenylphenol formaldehyde polymer, p-fluorophenol formaldehyde polymer, p-chlorophenol formaldehyde polymer, p-furomophenol formaldehyde polymer, p-iodophenol formaldehyde polymer, p- Nitrophenol formaldehyde polymer, p
-carboxyphenol formaldehyde polymer, o-
Carboxyphenol formaldehyde polymer, P-carbalkoxyphenol formaldehyde polymer, p-aroylphenol formaldehyde polymer, p
-lower alkoxyphenol formaldehyde polymer,
p-alkyl (C, ~C,2) phenols, such as p-
Ethylphenol, p-ethylphenol, p-n-propylphenol, p-isof.

Lopyruphenol, p-n-amylphenol, p-isoamylphenol, p-cyclohexylphenol,
p-1,1-dimethyl-n-propylphenol, p-yaman-hexylphenol, p-inhexylphenol, p-111-dimethyl-n-butylphenol, p-
1,2-dimethyl-n-butylphenol, p-n-hef. Tylphenol, p-isohef. tilphenol,
p-5.5-dimethyl-n-amylphenol, p-1
11-dimethyl-n-amylphenol, p-n-octylphenol, p-111.3.3-tetramethylbutylphenol, p-isooctylphenol, p-n
Nonylphenol, p-isononylphenol, p-1.13.3-tetramethylaminephenol, p-n
-deJ sinolephenol / p-isodetosinolephenol, p-n-undecylphenol, p-isoundecylphenol, p-n dodecylphenol, and the p-alkylphenol (the number of carbon atoms in the alkyl group is 1
-12) isomers, and copolymers of formaldehyde and mixtures containing two or more of the alkylphenols and their isomers. Further, even if an m-substituent is added to the p-monolayer phenol, it behaves in the same manner, and the addition of the m-substituent is not important. Further, the aromatic carboxylic acids in the metal salts of aromatic carboxylic acids include those represented by general formula (m). In the formula, R,, R2
, R3 ``R4 and R5 each represent a hydrogen atom, a halogen atom, a nitro group, an aldehyde group, an alkyl group, a cycloalkyl group, an aryl group, an alkylaryl group, an aralkyl group, and an alkoxy group.

R,, R2 "R3, R4, and R5 can be ring-closed with each other at adjacent positions. Among the compounds represented by the above general formula, the compound represented by the general formula (W) is particularly practical in the present invention.

General formula W [In the formula, R,, R2, R3 and R4 are the same as above.

] Alkali metal salts of aromatic carboxylic acids include sodium salts, potassium salts, lithium salts, cesium salts, and the like. Specific examples of aromatic carboxylic acids include benzoic acid, chlorobenzoic acid (o, mp), nitrobenzoic acid (o, mp),
p), toluic acid (o, m, p), 4-methyl-3-nitrobenzoic acid, 2-chloro-4-nitrobenzoic acid, 2
13-dichlorobenzoic acid, 214-dichlorobenzoic acid,
p-isopropylbenzoic acid, 205-dinitrobenzoic acid, p-butylbenzoic acid, N-phenyl anthranilic acid, 4-methyl-3-nitrobenzoic acid, salicylic acid, m-hydroxybenzoic acid to p-hydroxybenzoic acid,
3'5-dinitrosalicylic acid, 5-rt-butylsalicylic acid, 3-phenylsalicylic acid, 3-methyl-5-t
e ratio-butylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 305-di-rt-amylsalicylic acid,
3-cyclohexyl 315-di(Q-methylbenzyl)
Salicylic acid, 305-di(Q・Q dimethylbenzyl)salicylic acid, salicylic acid, 5-cyclohexylsalicylic acid, 3-methyl-5-isoamylsalicylic acid, 5-isoamylsalicylic acid, 315-DiSec-phthylsalicylic acid, 5-nonylsalicylic acid to 2-hydroxy -3-methylbenzoic acid, 2-hydroxy-5-sasart-butylbenzoic acid, 2,4-cresotinic acid to 5,5-methylenedizalicylic acid "acetaminobenzoic acid (contains o, m, p 204
-dihydroxybenzoic acid, 205-dihydroxybenzoic acid, anacardic acid, 1-naphthoic acid "2-naphthoic acid"
1-Hydroxy-2-naphthoic acid 2-hydroxy-3
Examples include naphthoic acid, 2-hydroxy-1-naphthoic acid, thiosalicylic acid, and 2-carboxybenzaldehyde.

On the other hand, the hydrophilic metal salts that react with alkali metal salts of aromatic carboxylic acids to produce metal salts of aromatic carboxylic acids as head coloring agents include those in Group IB of the periodic system such as copper and lead, magnesium, and calcium. etc. DA group: zinc, cadmium, mercury, etc. OB
Group: Aluminum, potassium, etc. mA Group: Tin, lead, etc. NA
Group; WB group such as chromium, molybdenum; B group such as manganese,
Examples include hydrochlorides, sulfates, and nitrates of related metals such as cobalt and nickel.

Among these metals, the ones that are particularly effective are zinc, tin,
Hydrochlorides, sulfates, and nitrates of aluminum, magnesium, and calcium. Among the various color developers mentioned above, the effects of the present invention are particularly great when clays are used.

The effect of the pressure-sensitive recording sheet using the color former of the present invention was confirmed using the following color developer sheet.

0.3 parts of sodium xametaphosphate was dissolved in 10 parts of water, and 3 parts of activated clay was uniformly dispersed therein.

Next, the pH of the dispersion was adjusted to 95 using a 20% aqueous sodium hydroxide solution, and 5 parts of solid SBR latex was added as a binder to obtain a pigment coating solution. The base paper was coated with a solid content of 89' using an air knife coater and dried.

In the manner described above, a color developer sheet coated with activated Shiroshi as a color developer was obtained. Example 1 1Q-tris(4dimethylaminophenyl)-
Synthesis of bisphenyster phosphate was performed as follows.

Crystal Violet Hydrochloride 8.0 60-700
0.0 warm water was poured into the ground and 15M of 25% sodium hydroxide aqueous solution was added, and light reddish brown tris-(4-dimethylaminophenyl)-carbinol was precipitated.

Add 300 pieces of 1,2-dichloroethane to this,
Immediately poured the mixture for about 1 hour to extract carbinol. The extract was washed with water, dried, and the head triphenyl phosphate 7.1
Add triethylamine 640g, 70-8000g
The reaction was carried out at a temperature of 7 hours. After the reaction, the reaction solution is cooled,
It was washed with 200 M of 5% aqueous sodium hydroxide solution, the precipitate was evaporated, and then washed with 200 M of 3% aqueous acidic acid. The product is dried over anhydrous magnesium sulfate, the solvent is distilled off, and the residue is recrystallized from methanol to give the following formula.

A pale yellow crystal of Q.Q-tris(4-dimethylaminophenyl)phosphate-bisuphenylester was obtained with a melting point of 184-185°C.The elemental analysis value of this compound was the theoretical value. Capsules containing the coloring agent obtained above were manufactured as follows: Acid-treated pork skin gelatin (1) Isobe and Arapiya gum (1) Ikarito were dissolved in 4000 g of water and 40 parts of Ikari was used as an emulsifier. Funnel oil 0.2
1 part, and 40 parts of color former oil is emulsified and dispersed therein.

The coloring agent oil was prepared by dissolving 2% of Q.Q.Q-tris(4-dimethylaminophenyl)-bisphenyl phosphate obtained by the above synthesis in diisopropylnaphthalene. When the size of the oil droplets reaches 5 microns on average, stop the emulsification, add 40 CO of water, strain the whole mixture 90 times a day, and continue to mix. At this time, the liquid temperature is
Care must be taken to ensure that the temperature does not drop below 40°C.
Then, 10% acetic acid was added to adjust the pH of the solution to 4.0-4.
2 to cause coacervation. The fly azusa is continued for 20 minutes, and after 20 minutes, it is cooled with ice water to gel the coacervate film deposited around the oil droplets. When the liquid temperature reaches 20 oo, add 7 parts of 37% formalin. When the pH reached 10q0, a 15% aqueous solution of caustic soda was added to adjust the pH to 9.

Next, pour water over the water for 20 minutes while shaking the water to bring the temperature of the liquid to 50o. The microcapsule dispersion thus obtained was heated to 30°C.
After adjusting the amount to 40 days, it was coated and dried on paper to a solid content of 6 days.

In the manner described above, a microcapsule sheet containing the color former of the present invention was obtained.

This capsule sheet is layered with a complexion agent sheet coated with activated clay, and ``When you write under pressure, a bluish-purple writing image slowly develops on the developer sheet in the area where pressure is applied, and the fully colored pigment is exposed directly to the surface of the color developer sheet. Almost no discoloration or fading was observed even when exposed to sunlight for a long time, and the water resistance and sublimation resistance were also excellent.In addition, crystal biot lactone and Q'Q Q-tris-( When a similar test was carried out using microcapsule sheets each containing 2% of 4-dimethylaminophenyl)-bisphenyester phosphate, a tone-purple colored image was obtained immediately after writing, and the colored image was not visible in direct sunlight. Almost no discoloration or fading was observed even when exposed to light for a long time.A similar effect was also obtained using a developer sheet coated with paraphenylphenol formalin resin or zinc 305-ditertiarybutylsalicylate as a developer. Obtained.

Claims (1)

[Claims] 1. A compound represented by the general formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1 is a lower alkyl group, and R_2 is a hydrogen atom or a lower alkyl group.) as a color former A pressure-sensitive recording sheet characterized in that it is used.