EP0275110A2 - Colour-developing sheet for pressure-sensitive recording, and colour-developing material therefor - Google Patents

Abstract

Color developing sheets and color developing agents are described which contain an inorganic solid acid in combination with a polyvalent metal salt of a carboxylated terpene phenolic resin and / or a reaction product of a carboxylated terpene phenolic resin, an aromatic carboxylic acid and a compound of a polyvalent metal. These color development sheets have higher water resistance and better resistance to yellowing.

Description

The invention relates to a color developing sheet and color developing agents which contain an inorganic solid acid as a color developing agent and in which the storage stability is improved.

Pressure sensitive recording sheets are known as carbonless copy papers. When using mechanical pressure or impact pressure when writing or typing on a typewriter, they produce a colored impression and thus allow the simultaneous production of several copies. A colored image is formed due to the color development reaction between an electron donating colorless dye and an electron accepting color developing agent.

So far, many electron-accepting color developing agents are known. Typical color developing agents are inorganic solid acids such as activated clay, attapulgite, etc. (described in USP 2712507); substituted phenols and diphenols (described in Japanese Patent Publication 9309/1965); p-subst. phenol-formaldehyde polymers (described in Japanese Patent Publication 20144/1967); Metal salts of aromatic carboxylic acids (described in Japanese Patent Publications 10856/1974 and 1327/1977, etc.); 2,2ʹ-bis-phenolsulfone compounds (described in JP-OS 10 6313/1979 etc.).

An inorganic solid acid adsorbs and reacts with the above electron donating dye to give a colored image. Acidic clay, for example a clay of the montmorillonite series, is used as the inorganic solid acid; activated clay made by acid treatment of an acid clay; Attapulgite, which is magnesium aluminum silicate ore, and the like. These inorganic solid acids have a variety of practical uses as color developing agents for pressure sensitive recording sheets because of their high adsorbability, they result in a rapid color development rate, a high image density and a clear color tone. However, they have the disadvantages that a colored image tends to discolor when exposed to UV rays, etc., that an image colored by a black color developing agent gradually turns reddish black, and that a colored image disappears after some time in the presence of moisture. To overcome these drawbacks, an improved process for the preparation of the inorganic solid acid, its use in combination with a polyvalent metal salt, an aromatic carboxylic acid, or other processes has been proposed. But these measures are insufficient.

The invention has for its object to provide a color development sheet for pressure-sensitive records, in which the image resistance to the action of sunlight and the water resistance are improved.

This object is achieved in a color developing sheet using an inorganic solid acid as a color developing agent in that the above inorganic solid acid in combination with a polyvalent metal salt of a carboxylated terpene phenolic resin and / or a reaction product of a carboxylated terpene phenolic resin, an aromatic Carboxylic acid and a polyvalent metal compound is used. It is found that the disadvantageous change and discoloration of the image when exposed to sunlight and the extinction of the image in the presence of water are significantly improved, whereby a rapid color development rate and a high image density are achieved as advantages of the color developing agent containing an inorganic solid acid. Typical examples of inorganic solid acids according to the invention are acid clay, attapulgite, zeolite, bentonite, kaolin, silica, synthetic silica, aluminum silicate, zinc silicate and the like, and their chemical or physical treatment products. A polyvalent metal salt of a carboxylated terpene phenol resin and a reaction product of a carboxylated terpene phenol resin, an aromatic carboxylic acid and a polyvalent metal compound, both of which are used in this invention, are new color developing agents. They are color developing agents for color developing sheets with superior yellowing resistance and better plasticizer resistance.

The carboxylated terpene phenol resin is produced as described in Japanese Patent Application No. 159540/1985 by the following procedure.

The addition reaction of cyclic monoterpene and phenol is carried out in a suitable solvent, for example a petroleum product, in the presence of an acid catalyst, for example aluminum trichloride, boron trifluoride, sulfuric acid, polyphosphoric acid, etc., to give a condensation product. Typical examples of the cyclic monoterpene are pinene, limonene, terpinolene, mentadiene, gum turpentine oil, which contains α-pinene as the main component, dipentene, which contains α-limonene as the main component, and so on. Typical examples of the phenol are monophenols such as carbolic acid, alkylphenol, alkoxyphenol, halogenated phenol, etc .; and polyhydric phenols, for example resorcinol, pyrocatechol etc. Typical examples of suitable solvents are benzene, toluene, xylenes, n-hexane, n-heptane, halogenated solvents, for example dichloromethane, chloroform, trichloromethane, bromobenzene and the like. The condensation product is made alkaline by adding alkali metal, alkali metal hydroxide or carbonate and is introduced at 140-180 ° C and 5-30 atm with introduction of carbon dioxide gas. treated in an autoclave (Kolbe-Schmitt reaction), the carboxy group being introduced into the condensation product. After the reaction, the solvent is distilled lation removed. After cooling to room temperature, the product is washed out to remove unreacted compounds. The product is further extracted with a dilute basic aqueous solution and then neutralized, whereby the carboxylated terpene phenol resin is excreted. The resin obtained is filtered off and washed out in order to obtain the purified carboxylated terpene phenol resin. The polyvalent metal salt of a carboxylated terpene phenol resin is prepared by reacting a carboxylated terpene phenol resin with a polyvalent metal oxide, hydroxide, chloride, carbonate, sulfate or the like in the presence of an inorganic ammonium salt with melting, or a carboxylated terpene phenol resin with alkali metal hydroxide in one Solvents such as water, alcohol, etc. dissolve, add and react with a polyvalent metal salt, or the like.

Examples of the polyvalent metals are magnesium, aluminum, calcium, cadmium, titanium, zinc, nickel, cobalt, manganese, etc .; Magnesium, aluminum and zinc are preferred. Zinc is most preferred.

The reaction product between the above carboxylated Terpene phenolic resin, aromatic carboxylic acid and polyvalent metal compound is prepared by uniformly mixing the carboxylated terpene phenolic resin, aromatic carboxylic acid and polyvalent metal compound and then reacting with each other, or by mixing two of the above three ingredients and then with one other component can react.

Uniform mixing is achieved by dissolving these ingredients in a solvent with stirring, or melting with heating, or by using other methods.

Typical examples of the solvents are alkaline aqueous solutions such as sodium hydroxide, potassium hydroxide, sodium carbonate, etc .; and organic solvents such as alcohol, acetone, etc .; and the mixture of them.

The aromatic carboxylic acid (monocyclic or polycyclic) is one in which the carboxy group is bonded directly to the ring. Typical examples of the aromatic carboxylic acid are: benzoic acid, p-hydroxybenzoic acid, chlorobenzoic acid, bromobenzoic acid, nitrobenzoic acid, methoxybenzoic acid, ethoxy benzoic acid, toluic acid, ethylbenzoic acid, pn-propylbenzoic acid, p-isopropylbenzoic acid, 3-methyl-4-hydroxybenzoic acid, 3-ethyl-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, p-tert.-butylbenzoic acid, o-benzoylbenzoic acid Cyclohexylbenzoic acid, salicylic acid, 3-methyl-5-tert-butylsalicylic acid, 3,5-di-tertiary-butylsalicylic acid, 5-nonylsalicylic acid, 5-cyclohexylsalicylic acid, 3-cyclohexylsalicylic acid, 3,5-diamylsalicylic acid, cresotonic acid, 5-cyclic acid, , 3-phenylsalicylic acid, 3,5-sec-butylsalicylic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, gallic acid, naphthoic acid, phthalic acid monobenzyl ester, phthalic acid monocyclohexyl ester, salicylosalicylic acid, 3-tert.-butyl acid-3-α-methyl-5-α-methyl-a-benzyl , 5-Di (α-methylbenzyl) salicylic acid, phthalic acid, terephthalic acid, isophthalic acid, diphenic acid, naphthalenedicarboxylic acid, naphthalic acid, and so on.

Of these carboxylic acids, the monocarboxylic acids are preferred. Typical examples of suitable polyvalent metal compounds are oxides, halides, carbonates, sulfates, nitrates, acetates, formats, oxalates, benzoates, acetylacetone salts and salicylates of magnesium, aluminum, cadmium, calcium, titanium, zinc, nickel, cobalt, manganese, vanadium etc. ; Magnesium, aluminum and zinc compounds are preferred; Zinc compounds are most preferred.

• (1) Jedes der Farbentwicklungsmittel wird mit einem Disper­giermittel zusammen gemischt und dispergiert, dann gibt man Füller, Bindemittel usw. zu den gemischten Farbent­wicklungsmitteln;
• (2) Farbentwicklungsmittel werden zusammen mit einem Dis­pergiermittel dispergiert, und Füller, Bindemittel usw. werden zu den dispergierten Farabentwicklungsmitteln ge­geben, oder
• (3) Farbentwicklungsmittel werden gemischt, dann durch Erhitzung oder in einem Lösungsmittel dispergiert,und Füller, Bindemittel usw. werden zu den dispergier­ten Farbentwicklungsmitteln gegeben.

The amount of the polyvalent metal salt of a terpene phenol resin and / or the reaction product of a carboxylated terpene phenol resin, an aromatic carboxylic acid and a compound of a polyvalent metal based on the inorganic solid acid is not particularly limited, and is preferably at least 1% by weight, more preferably at least 30% by weight. The inorganic solid acid, the metal salt of a carboxylated terpene phenol resin, and the reaction product of a carboxylated terpene phenol resin, an aromatic carboxylic acid and a compound of a polyvalent metal are each dispersed in water or a solvent and then used. A coating slip for color developing agents is made as follows:

• (1) Each of the color developing agents is mixed and dispersed together with a dispersant, then filler, binder, etc. are added to the mixed color developing agents;
• (2) Color developing agents are dispersed together with a dispersing agent, and fillers, binders, etc. are added to the dispersed color developing agents, or
• (3) Color developing agents are mixed, then by Heating or dispersed in a solvent, and fillers, binders, etc. are added to the dispersed color developing agents.

A color developing sheet is prepared by applying the coating slip obtained above as a simple layer on a substrate. However, multi-layer coating methods can also be used, in which case a coating composition containing a color developing agent is first applied to a substrate and then another coating composition containing another color developing agent, and the like.

The color developing agents of the present invention are used in all fields related to pressure sensitive recording sheets. Examples are: Pressure sensitive recording sheets, e.g. have a middle sheet, lower sheet, single recording sheet, etc., or in which the color developing agent of the present invention is coated on or mixed with the support material; Testing agent for a leuco dye after dissolving in an organic solvent: spot printing ink mixed with a wax; pressure sensitive ink using the color developing agent and / or microcapsules containing the leuco dye.

• (a) Auftragen der wäßrigen Streichmasse auf das Träger­material, wobei eine wäßrige Suspension des Farb­entwicklungsmittels verwendet wird.
• (b) Zugabe des Farbentwicklungsmittels zu dem Stoff bei der Papierherstellung.
• (c) Auftragen des in einem Lösungsmittel gelösten oder suspendierten Farbentwicklungsmittels auf das Trägermaterial.

A color development sheet with an inventive Color developing agent, is produced by known methods, for example by

• (a) applying the aqueous coating slip to the substrate, using an aqueous suspension of the color developing agent.
• (b) adding the color developing agent to the fabric in papermaking.
• (c) applying the color developing agent dissolved or suspended in a solvent to the support material.

The coating slip according to the invention is produced by mixing kaolin clay, calcium carbonate, treatment starch, polyvinyl alcohol, synthetic or natural latex etc. and imparting the mixture with suitable viscosity and spreadability. It is advantageous to use 10-70% by weight of color developing agent, based on the total solids in the coating slip. With less than 10% by weight of color developing agent, the color developing ability is insufficient, with more than 70% by weight of color developing agent, on the other hand, the surface properties of the color developing sheet deteriorate.

It is also advantageous to apply the color development layer to a support in a coating amount of at least 0.5 g / m², preferably 1.0-10.0 g / m².

The color developing agent of the present invention is suitable for many known dyes used in pressure sensitive recording sheets.

Examples of typical pressure sensitive dyes are;
Triphenylmethane series dyes such as crystal violet lactone, malachite green lactone, 3-dimethylaminotriphenylmethanephthalide, etc .;
Fluoran series dyes, such as 3,6-dimethoxyfluorane, 3-N-cyclohexylamino-6-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 1,2-benzo-6-diacethylaminofluorane, 1,2-benzo- ( 2ʹ-diethylamino) -6-diethylamino-fluoran, 3-diethylamino-7-dibenzylamino-fluoran, 3-diethylamino-6-methyl-7-dibenzylamino-fluoran, 3-diethylamino-5-methyl-7-dibenzylamino-fluoran, 3 -Diethylamino-7-anilino-fluoran, 3-diethylamino-6-methyl-7-anilino-fluoran, 3-diethylamino-7- (o-acethyl) anilino-fluoran, 3-diethylamino-7-piperidino-fluoran, 3- Diethylamino-7-pyrolidino-fluoran, etc .:
Spiropyran series dyes, such as spiro (3-methylchromene 2,2ʹ-7ʹ-diethylaminochromes), spiro (3-methylchromene-2,2ʹ-7ʹ-dibenzylaminochromes), 6ʹ, 8ʹ-dichloro-1,3,3-trimethyl-indolino-benzospiropyran, 1,3,3-trimethyl- 6ʹ-nitro-spiro (indoline) -2,2ʹ-2ʹH chromene, spiro (1,3,3-trimethylindoline-2,3ʹ-8ʹ-bromonaphtho (2,1-b) pyran, spiro (3-methyl-benzo ( 5,6-a) chromene-2,2ʹ-7ʹ-diethylaminochromene, etc .;
Phenothiazine series dyes, such as 3-diethylamino-7 (N-methylanilino) -10-benzoylphenoxazine, 3,7-bis (dimethylamino) -10-benzoylphenothiazine, 10- (3ʹ, 4ʹ, 5ʹ-trimethoxy-benzoyl) -3, 7-bis (dimethylamino) phenothiazine, etc .;
Azaphthalide series dyes such as 3- (4-diethylamino-2-athoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) 7-azaphthalide, etc .;
Indole series dyes such as 3,3-bis (1-octyl-2-methylindol-3-yl) phthalide, etc .; and
Triphenylmethane series dyes such as N-butyl-3 (bis- (4- (N-methylanilino) phenyl) methyl) carbazole, etc.

This invention significantly improves both the yellowing resistance (the resistance to change and discoloration of the image when exposed to sunlight) and the water resistance compared to a color developing sheet with an inorganic solid acid as a color developing agent. Presumably, the polyvalent metal salt of a carboxylated terpene phenolic resin or the reaction product of a carboxylated terpene phenolic resin, an aromatic carboxylic acid and a polyvalent metal compound, in the combined use described herein, provide the above advantages.

(Examples)

The invention is explained in more detail with reference to the following examples and comparative examples.

The following examples and comparative examples serve only to illustrate the invention. they should not limit them. "Parts" and "Percent" are parts by weight and% by weight unless otherwise specified.

The method of manufacturing a transfer sheet in which microcapsules containing the pressure sensitive dye were coated on a sheet of fine paper, and the evaluation method of the color development sheet using the transfer sheet is as follows.

Production of a transfer sheet

90 parts of dilution water was mixed with 90 parts of a 10% aqueous solution of ethylene-maleic anhydride copolymer (trade name EMA, manufactured by Monsanto Co.). 10 parts of urea and 1 part of resorcinol were dissolved in this mixed solution, and then the pH of the solution was adjusted to 3.4.

On the other hand, an oil mixture of alkyl diphenylethane (trade name: Hisol SAS 296, manufactured by Nisseki Kogaku Co.) and diisopropylnaphthalene (trade name KMC-113, manufactured by Kureka Kogaku Co.) was prepared in a weight ratio of 1: 1. As the core substance to be encapsulated, there were prepared: (a) an oil of a blue color developing pressure sensitive dye by dissolving 3% crystal violet lactone and 1% benzoyl leucomethylene blue in the above oil mixture; and (b) an oil of a black color developing pressure sensitive dye by dissolving 5% 3-diethylamino-6-methyl-7-anilinofluorane, 1% 3- Diethyl-amino-6-methyl-7-diphenylmethylaminofluoran and 0.5% 3-diethylamino-6-methyl-7-chlorofluoran in the above oil mixture.

180 parts of each of these oils (a) and (b) of the pressure sensitive dyes were added to the above aqueous solution and emulsified to the average particle size of 4 microns. Subsequently, 27 parts of a 37% strength aqueous formaldehyde solution were heated to 55 ° C., reacted for 2 hours at 55 ° C. to form the capsule wall, and a 28% strength aqueous ammonia solution was added to pH 7.5. In this way, two capsule slurries with microcapsules containing pressure-sensitive dyes were obtained.

180 parts of capsule slurry, 35 parts of wheat starch and 85 parts of an 8% aqueous oxidized starch solution were mixed to prepare a coating composition. The coating composition was applied in a coating amount of 4.5 g / m² on a base paper of 45 g / m² and dried. In this way, two transfer sheets, that is, (A) a transfer paper developing blue color, and (B) a transfer paper developing a black color.

Evaluation of the color development sheet

Each of the two transfer sheets described above and a color development sheet according to the examples or comparative examples were placed on top of each other so that a color was formed.

The color development speed, color development intensity and light fastness of the sheets were measured, and the test results are summarized in Table 1.

1) Color development speed and final color development intensity

Und die Farbentwicklungsgeschwindigkeit nach 24 Stunden bzw. die Intensität der endgültigen Farbentwicklung wird nach folgender Gleichung berechnet;

Höhere Farbentwicklungsgeschwindigkeit und Intensität der endgültigen Farbentwicklung sind erwünscht.A CB sheet in which a support is coated with a microcapsule containing pressure-sensitive dye and a color developing sheet in which a support is coated with a color developing agent are laid so that the coated surfaces of the sheets touch each other. A color image is generated with the grid plate roll calender. The reflectance of the sheet is measured with a Hunter reflectometer (D-type; from Toyo Seiki Co.) measured using an amber filter. The color development speed (J₁ or J₂) is calculated from the reflectance I₀ before the color development, the reflectance I₁ of 10 seconds after the color development or the reflectance I₂ of 24 hours after the color development. The image density at 10 seconds after color development is calculated according to the following equation:

And the color development speed after 24 hours or the intensity of the final color development is calculated according to the following equation;

Higher color development speed and intensity of final color development are desirable.

2. Resistance to yellowing (Resistance to change and discoloration of the image when exposed to sunlight)

The surface of a color development sheet is exposed to sunlight for 8 hours 24 hours after color development (measured by the method described in (1)). The reflectance of the blue color development surface (8 hours after the completion of the development is measured using a Hunter reflectometer.

The image density (J₃) is calculated according to the following equation.

The resistance to yellowing (H) (against discoloration when exposed to sunlight) is calculated as follows.

Higher resistance to yellowing is desirable. The yellowing resistance of the black color developing surface is observed with the naked eye.

3. Water resistance

The color development sheet 24 hours after color development (measured by the method described in (1)) is immersed in water for about 3 hours. Then the water resistance is observed with the naked eye.

(Example 1) Preparation of water suspension of inorganic solid acid

300 parts of water in which 1 part of sodium pyrophosphate as a dispersant is dissolved and 100 parts of activated clay (trade name: Shilton DR-1, manufactured by Mizusawa Chemical Co.) were dispersed with vigorous stirring by means of a stirrer, whereby a water suspension No. 1 received.

Preparation of the water suspension of the carboxylated terpene phenolic resin zinc salt

100 parts of a carboxylated terpene phenolic resin zinc salt prepared from α-pinene and carbolic acid as raw materials) were added to 147.5 parts of water in which 2.5 parts of sodium polyacrylate had been dissolved and dispersed to an average particle size of 3 μm by means of a sand grinding machine, whereby a water suspension no. 2 received.

Preparation of the color development sheet

Water suspension No.1 100 parts
Water suspension No.2 30 parts
Styrene butadiene latex (concentration: 40%) 20 parts
Oxidized starch 10 parts

The mixed solution of the above recipe was adjusted to pH 8.5 with sodium hydroxide solution, and a coating composition having a solids content of 30% was prepared with the addition of water. The coating composition was applied to a sheet of 50 g / m² using a Meyer device, so that the amount of coating composition applied after drying was 6 g / m². A color development sheet was obtained.

(Example 2)

A color developing sheet was prepared in the same manner as in Example 1, but using a reaction product of carboxylated terpene phenol resin (made from limonene and carbolic acid as raw materials), 3,5-di-tert-butylsalicylic acid and zinc chloride in Example 1.

(Example 3)

A color developing sheet was prepared in the same manner as in Example 1, except that a carboxylated terpene phenol resin zinc salt (made from rubber turpentine oil and O-cresol as raw materials) was used in place of the carboxylated terpene phenol resin zinc salt in Example 1.

(Comparative Example 1)

A coating composition of the following formulation was prepared using water suspension No. 1.
Water suspension No.1 100 parts
Styrene butadiene latex (concentration: 40%) 18 parts
Oxidized starch 6 parts

The above mixed solution was mixed with sodium hydroxide solution adjusted to pH 8.5, and a coating composition with 30% solids content was prepared with the addition of water.

As shown in Table 1, the color developing sheet of the present invention, which contains an inorganic solid acid in combination with a polyvalent metal salt of a carboxylated terpene phenol resin and / or a reaction product of a carboxylated terpene phenol resin, an aromatic carboxylic acid and a compound of a polyvalent metal, has a higher water resistance and better resistance to yellowing (image resistance to sunlight) than a color developing sheet containing only an inorganic solid acid.

As described above, this invention results in a conventional color developing sheet having higher water resistance and better resistance to yellowing (resistance to change and discoloration of the image when exposed to sunlight) while maintaining a high color development rate and high image density.

Claims (11)

1. a color developing sheet for pressure-sensitive recordings using an inorganic solid acid as a color developing agent and an electron donating colorless dye as a color forming agent,

characterized in that

the color development sheet has at least one color development layer on a support which contains the inorganic solid acid in combination with at least one additive, namely a polyvalent metal salt of a carboxylated terpene phenol resin and / or a reaction product of a carboxylated terpene phenol resin, an aromatic carboxylic acid and a compound of a polyvalent metal. 2. Color development sheet according to claim 1, characterized in that the polyvalent metal is magnesium, aluminum and / or zinc, in particular zinc. 3. Color development sheet according to one of claims 1 and 2, characterized in that the aromatic carboxylic acid is an aromatic monocarboxylic acid. 4. Color development sheet according to one of claims 1 to 3, characterized in that the addition is at least 1 wt .-%, based on the inorganic solid acid. 5. Color development sheet according to claim 4, characterized in that the addition is at least 30 wt .-%, based on the inorganic solid acid. 6. Color development sheet according to one of claims 1 to 5, characterized in that the color development layer contains 10 to 70 parts by weight of color development agent, based on the total solids content. 7. Color development sheet according to one of claims 1 to 6, characterized in that the ready-to-use color development layer has a basis weight of 1.0 to 10.0 g / m². 8. Color development sheet according to one of claims 1 to 7, characterized in that the color developing agent is used in combination with triphenylmethane, fluoran, spiropyran, phenothiazine, phthalide and / or indolleuco dyes. 9. Color developing agent for pressure-sensitive recording sheets based on solid inorganic acids and conventional constituents of color developing agents, characterized in that it contains, as an additive, a polyvalent metal salt of a carboxylated terpene phenolic resin and / or a reaction product of a carboxylated terpene phenolic resin, an aromatic carboxylic acid and a polyvalent metal compound . 10. Color developing agent according to claim 9, characterized in that the polyvalent metal is magnesium, aluminum, zinc, cadmium, calcium, titanium, nickel, cobalt, manganese and / or vanadium, in particular magnesium, aluminum and / or zinc, preferably zinc. 11. Color developing agent according to claim 8 or 9, characterized in that the addition is at least 1 wt .-%, preferably at least 30 wt .-%, based on the phenolic resin.