JPH03254988A - Color developer for pressure-sensitive recording paper, production thereof, and color developing sheet using the same - Google Patents

Abstract

PURPOSE:To obtain a color developing sheet for pressure-sensitive recording having good color forming properties, no possibility of yellowing even under the exposure to a sunlight, and superior shelf stability by a method wherein a phenol is reacted with a formaldehyde in the presence of an acid catalyst and added with carboxyl groups, and a color developer made of a polyvalent metal salt of this product is fixed on a substrate. CONSTITUTION:A phenol and a formaldehyde are heated in the presence of an acid catalyst in water or an organic solvent pref. at a temp. of 70-100 deg.C for 3-15 hours, thereafter being dehydrated or solvent-removed under an atmosphere or a reduced pressure. A phenolic hydroxyl group is made a sodium phenol using a metallic sodium, sodium hydride, or sodium hydroxide. The sodium phenol is reacted with carbon dioxide gas under heat and pressure to produce a carboxy-modified phenol resin. This carboxy-modified phenol resin is heated and melted at a temp. of 100-170 deg.C to be reacted with an oxide, hydroxide, chloride, carbonate, or sulfate of a polyvalent metal and an inorganic ammonium salt, such as ammonium carbonate. This is washed and dried to obtain the polyvalent metallic salt of the carboxy-modified phenol resin as a color developer. By fixing said color developer on a substrate, such as paper or a plastic film, using a binder, a color developing sheet is made available.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a color developer for pressure-sensitive recording paper, a method for producing the same, and a color developer sheet formed by fixing the same to a support.

(Prior Art) Pressure-sensitive recording paper is known from U.S. Patent No. 2,712,507, U.S. Pat. This method is based on the fact that microcapsules enclosing a colorless color former are destroyed by pressure, and the color former reacts with an electron-accepting color developer to develop color.

As a color developer for obtaining such pressure-sensitive recording paper, acid clay, activated clay, inorganic solid acids such as attapulgide, kaolin, and zeolite, novolac type phenolic resin, and Japanese Patent Publication No. 42-20゜144-inch have been used. p-substituted phenol-formaldehyde resins as disclosed, aromatic carboxylic acid metal salts as disclosed in Japanese Patent Publication No. 49-10゜856, Japanese Patent Publication No. 52-1,327, etc. are used. .

However, inorganic solid acids have a color-forming reaction rate (color-forming property)
Although the quality is good, the stability of the colored image against moisture and light is poor. In addition, novolak type phenolic resins and p-substituted phenol-pormaldehyde resins tend to yellow when the color developing sheets obtained using them are exposed to sunlight, and even when stored in a cool dark place, and are storage stable. The problem was that they were inferior in gender. Further, aromatic carboxylic acid metal salts have a problem in that the resulting colored images significantly deteriorate in sharpness when they come into contact with water or plasticizers, and are inferior in water resistance and plasticizer resistance.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems of conventional color developers for pressure-sensitive recording paper.

Therefore, an object of the present invention is to provide a color developer sheet for pressure-sensitive recording paper that has good color development properties, hardly yellows even when exposed to sunlight, and has excellent storage stability, and a developer that provides the color developer sheet. An object of the present invention is to provide a colorant and a method for producing the same.

(First Step to Solve the Problem) The present inventors have discovered that by using a polyvalent metal salt of a carboxyl-modified phenol resin obtained using specific raw materials and procedures as a color developer for pressure-sensitive recording, We have discovered that this goal can be achieved, and have arrived at the present invention.

That is, the present invention relates to a color developer for pressure-sensitive recording paper comprising a polyvalent metal salt of a product obtained by reacting phenols and formaldehyde under an acidic catalyst and introducing a carboxyl group into the reaction product.

The present invention is also characterized in that phenols and formaldehyde are reacted in the presence of an acidic catalyst to form an alkali phenolate, and then a carboxyl group is introduced by reacting with carbon dioxide gas to form a polyvalent metal salt. The present invention relates to a method for producing a color developer for pressure-sensitive recording paper.

The present invention further provides a color developer for pressure-sensitive recording paper, which is made of a polyvalent metal salt of the product obtained by reacting phenols and formaldehyde in the presence of an acidic catalyst and introducing a carboxyl group into the product, and fixing the color developer on the support. This relates to a color developing sheet made of.

(Function) The reaction between phenols and formaldehyde in the present invention is carried out in the following manner.

That is, phenols and formaldehyde are mixed in water or benzene, toluene, xylene,
60 in an organic solvent such as dioxane or tetrahydrofuran.
1-3 at a temperature of ~150°C, preferably 70-100°C
It can be synthesized by heating for 0 hours, preferably 3 to 15 hours, followed by dehydration or solvent removal under normal pressure or reduced pressure. Here, the usage ratio of formaldehyde to 1 mole of phenol is usually in the range of 0.5 to 1.0 mole, preferably 0.6 to 0.9 mole.

Examples of the phenols used in the present invention include phenol; cresol, ethylphenol, n-propylphenol, isopropylphenol, n-butylphenol, isobutylphenol, tert-butylphenol, n-amylphenol, isoamylphenol, 11-dimethyl -n-propylphenol, n-hexylphenol, isohexylphenol, i,1-dimethyl-n-butylphenol, 1,2-dimethyl-n
-butylphenol, n-hebutylphenol, isohebutylphenol, 5,5-dimethyl-n-amylphenol, n-octylphenol, 1,1,3.3-tetramethylbutylphenol, isooctylphenol, nonylphenol, ], 1,3 .Alkylphenols such as 3-tetramethylamylphenol, n-decylphenol, isodecylphenol, n-undecylphenol, isoundecylphenol, and n-dodecylphenol;Arylphenols such as phenylphenol and naphthylphenol;Benzylphenol cycloalkylphenols such as cyclohexylphenol, and resorcinol. Preferred among these are phenol, cresol, paraphenylphenol and other para-substituted alkylphenols.

Further, as the formaldehyde, formalin, which is an aqueous formaldehyde solution, is practical.

As the acidic catalyst, acids conventionally used in the production of novolac resins, such as inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, and organic acids such as acetic acid, oxalic acid, and paratoluenesulfonic acid, are used. The amount used is usually in the range of 0.05 to 5% by weight of IC1iTi, preferably 0.1 to 5% by weight, based on the phenol.

As a method for introducing a carboxyl group, various known methods for introducing a carboxyl group into an aromatic compound can be applied. A preferred method is the so-called Kolbe-Schmidt reaction, in which the phenolic hydroxyl group is converted to thorium phenol using metal strontium, lithium hydride, thorium hydroxide, etc., and then reacted with carbon dioxide gas under heat and pressure.

In the sodium phenol-1 production reaction and carboxyl group addition reaction, it is also possible to use aromatic hydrocarbons such as benzene, toluene, and xylene, and ethers such as dioxane and tetrahydrofuran as reaction solvents.

The produced carboxy-modified phenol resin is converted into a polyvalent metal by the following method.

(1) Polyvalent metal oxides, hydroxides, chlorides, carbonates,
A sulfate or the like and an inorganic ammonium salt such as aluminum carbonate are heated and melted at 100 to 170°C to react.

(2) It is dissolved in alcohol together with an alkali metal hydroxide such as sulfur/lium hydroxide or potassium hydroxide, and an alcohol-soluble polyvalent metal salt is added thereto and reacted.

Next, washing with water and drying are performed to obtain a polyvalent metal salt of carboxy-modified phenol resin. Polyvalent metals include zinc,
Magnesium, cadmium, aluminum, lead, titanium, calcium, cobalt, nickel, manganese, etc. may be mentioned, and among these, zinc is practically preferred.

The color developer obtained in the present invention can be used alone, but other known color developers may be used, such as inorganic solid acids such as activated white pigment, novolac type phenolic resin, p-substituted phenol-formaldehyde resin, It can also be used in combination with aromatic carboxylic acids and metal salts thereof.

In the present invention, in order to create a color developer sheet using a color developer for pressure-sensitive recording paper made of a polyvalent metal salt of a carboxyl-modified phenol resin, the developer is coated on a support such as paper or a plastic film. It may be fixed using a binder.

For example, a color developer dissolved or suspended in an aqueous dispersion or an organic solvent is mixed with a binder such as starch, synthetic rubber, or natural rubber latex, along with a filler such as kaolin, clay, or calcium carbonate, if necessary, and applied. Prepare the liquid,
By applying this onto a support and drying it, a color developing sheet is obtained. In general, the amount of coating liquid is 2 to 2 in terms of solid content.
10g:/rd, preferably 3-6 g/rrr
It is.

The color developer of the present invention is effective against color formers commonly used for pressure-sensitive recording paper, such as 3°3-bis(p
-dimethylaminophenol)-6 dimethylaminophthalide (crystalline violet lactone), 3.3
- Diarylphthalides such as bis(p-dimethylaminophenol) phthalide (malachite green lactone); leucouramines such as N-(23-cy')lorophenyl)-leucouramine; N-benzoyluramine , N-acetyloramine; arylauramines such as N-phenylauramine; α,β-unsaturated aryl lactones such as dibenlideneacetone, dibenzylideneacetone, anisylideneace), and Basic monoazo dyes such as -dimethylaminoazobenzene-〇-carboxylic acid (methyl red), 4-aminoazobenzene (oil yellow AAB), 4-phenylazo-]-naphthalamine;
Rhodamine B lactams such as N-(p-diI-lophenyl)-rhodamine Bilactam; polyarylcarpi such as bis(p=dimethylaminophenyl)-methanol, crystal violet carbinol, malachite green carbinol; Sols; 8'-methoxy-benzoindol such as 8-methoxy-benzoindolinospiropyran, 4,7.8'-trimethoxybenzoindolinospiropyran, 6'-chloro8-methoxy-benzoindolinospiropyran0 Nospiropyrans; used in combination with a coloring agent such as p-dimethylaminostyrylquinoline.

(Example) The present invention will be explained below with reference to Examples. In addition, % in the example
is weight %.

Example 1 A 2 g separable flask equipped with a thermometer, a stirrer and a reflux condenser was charged with 300 g of octylphenol, 300 g of xylene and 10 g of 36% concentrated hydrochloric acid, and heated to 80°C.
After heating, 89 g of 37% Polmarin was added dropwise over 1 hour, and the mixture was reacted at reflux temperature for 5 hours. The water and xylene layers were then separated.

Xylene was removed under reduced pressure to obtain a solid phenol resin (]). 000 g of the obtained phenol resin (1)] and 500 g of dehydrated and purified xylene were placed in a 2 g pressure-resistant reaction pot, and the phenol resin was dissolved. Next, metallic sodium 5
After heating to 140°C, the internal pressure of the pressure-resistant reactor was increased to 1. Okg/cn? Carbon dioxide gas was introduced until the temperature reached 1, and the reaction was continued for 6 hours. After cooling, the mixture was neutralized with hydrochloric acid and separated into a xylene layer and an aqueous layer. Thereafter, xylene was removed by vacuum distillation to obtain a carboxy-modified phenol resin (1). 80 g of the obtained carboxy-modified phenolic resin (1), 5 g of zinc benzoate and 5 g of ammonium bicarbonate were charged into a 1ρ separable flask, and reacted at 160°C for 3 hours to form a zinc salt of the carboxy-modified phenol resin (hereinafter referred to as modified phenol resin). Resin polyvalent metal salt (referred to as (1)) was obtained.

Example 2 In the same experimental apparatus as in Example 1, 300 g of phenol, 1
- After charging 300 g of toluene and 3 g of oxalic acid and heating to 80°C, 130 g of 37% Polmarin was added dropwise over 1 hour, and the mixture was reacted at reflux temperature for 3 hours. The water and toluene layers were then separated. Toluene was removed under reduced pressure to obtain a solid phenol resin (2).

100 g of the obtained phenol resin (2) and 500 g of dehydrated and purified xylene were placed in a 2 g pressure-resistant reaction pot.
The phenolic resin was dissolved. Next, 5g of metal sl/lium
After heating to 140°C, carbon dioxide gas was introduced at that temperature until the internal pressure of the pressure-resistant reaction vessel reached 10 kg/cJ, and the reaction was allowed to proceed for 7 hours. After cooling, the mixture was neutralized with hydrochloric acid and separated into a xylene layer and an aqueous layer. After that, xylene was removed by vacuum distillation, and carboxy-modified phenol resin (2
) was obtained. The obtained carboxy-modified phenol resin (2
), 5 g of zinc benzoate and 5 g of ammonium bicarbonate were placed in a separable flask of 19, and heated at 160°C.
The mixture was reacted for 3 hours to obtain a zinc salt of carboxy-modified phenol resin (modified phenol resin polyvalent metal salt (2)).

Example 3 In the same experiment apparatus as in Example 1, 300 g of p-tert-butylphenol, 300 g of xylene and p-) were added.
After preparing 3g of luenesulfonic acid and heating to 80℃,
122 g of 7% formalin was added dropwise over 1 hour, and the mixture was reacted at reflux temperature for 5 hours. The water and xylene layers were then separated. The xylene is removed under reduced pressure and solid phenolic resin (
3) was obtained. 1001g of the obtained phenolic resin (3)
And dehydration 3: Put 500g of purified xylene into a 2g pressure-resistant reaction pot,
The phenolic resin was dissolved. Next, metal (metal) 7g of lium
After heating to 140°C, carbon dioxide gas was introduced at that temperature until the internal pressure of the pressure-resistant reaction vessel reached 10 kg/at, and the reaction was allowed to proceed for 7 hours. After cooling, the mixture was neutralized with hydrochloric acid and separated into a xylene layer and an aqueous layer. Thereafter, xylene was removed by vacuum distillation to obtain a carboxy-modified phenol resin (3). 80 g of the obtained carboxy-modified phenol resin (3), 5 g of zinc benzoate, and 5 g of ammonium bicarbonate were charged into a 1-g separable flask, and reacted at 160°C for 3 hours to form a zinc salt of the carboxy-modified phenol resin (modified phenol resin polycarbonate). A valent metal salt (3)) was obtained.

Example 4 A nickel salt of a carboxy-modified phenol resin (modified phenol resin polyvalent metal salt (4)) was obtained in the same manner as in Example 3, except that nickel benzoate was used instead of zinc benzoate.

Comparative Example 1 170 g of p-tert-butylphenol, 200 g of toluene and 8.5 g of 20% hydrochloric acid were placed in the same separable flask 4 as used in Example 1, and heated until the liquid temperature reached 90°C. . 3 while being careful of fever
55 g of 7% formalin was added and kept at 90°C for 6 hours. Thereafter, the solvent was removed under reduced pressure to obtain a solid comparative phenol resin (1).

Example 5 Using the modified phenol resin polyvalent metal salts (1) to (4) obtained in Examples 1 to 4 and Comparative Example 1 and the comparative example phenol resin (1) as a color developer, the following composition was prepared. The color developer was dispersed in water using a sand mill to prepare an aqueous dispersion of the color developer.

Composition of aqueous dispersion of color developer Color developer 30 parts by weight Disco) N14 (manufactured by Kako Co., Ltd.) 3 parts by weight water
80 parts by weight Next, using each of these color developer aqueous dispersions, a color developer coating solution having the composition shown below was prepared.

Color developer coating solution composition Color developer aqueous dispersion 70 parts by weight 5 Calcium carbonate 90 parts by weight 50%
Styrene-butadiene rubber latex 15 parts by weight Oxidized starch 20 parts by weight Each of the obtained developer coating solutions was coated on high-quality paper at a solid content of 7 g/rr?
After coating, a color developing sheet was prepared by drying.

Using each of the obtained color developer sheets and a color developer sheet coated with color former-containing microcapsules manufactured by Business Paper Xabry Co., Ltd., the performance of the color developer sheets was evaluated in the following manner. The results are shown in Table 1.

Method for evaluating the performance of the color developer sheet (1) Color development The color developer sheet and the color developer sheet were superimposed and printed using an electric typewriter, and the clarity of the characters on the color developer sheet was observed. Evaluation was made on a three-level scale of ◎-〇-△ in descending order of clarity.

(2) A color developing sheet that had not developed color due to solar yellowing was exposed to direct sunlight for 20 hours, and the b values before and after exposure to sunlight were determined using CR'-100 (manufactured by Minolta Camera Co., Ltd.) at 1n11. b before and after sun exposure
The larger the Δb value, which is the difference in values, the more significant the yellowing.

(3) Plasticizer resistance (1) After storing the color developing sheet developed using the color development method in a cool and dark place for 24 hours, apply dioctyl phthalate to the color development surface. were observed and evaluated on a three-grade scale of ◎-〇-△ in descending order of clarity.

(4) Nitrogen oxide resistance yellowing The uncolored developing sheet is left in a nitrogen dioxide gas atmosphere for 2 hours in accordance with JIS L-1055.

), the b values before and after were measured using a color difference meter C manufactured by Minolta Camera Co., Ltd.
Measured with R-100. The larger the Δb value, the more remarkable the yellowing.

7 8 (Effects of the Invention) The color developer for pressure-sensitive recording paper made of a polyvalent metal salt of a carboxyl-modified phenol resin of the present invention has good color development properties and does not yellow even when exposed to sunlight. This provides a color developing sheet for pressure-sensitive recording paper that has extremely excellent storage stability. Further, the color developing sheet of the present invention does not yellow even when it comes into contact with oxidizing gases in the atmosphere such as nitrogen oxides, and furthermore, the sharpness of the obtained colored image is stable.

Claims (3)

[Claims] (1) A color developer for pressure-sensitive recording paper comprising a polyvalent metal salt of a product obtained by reacting phenols and formaldehyde in the presence of an acidic catalyst and introducing a carboxyl group into the reaction product. (2) A pressure-sensitive method characterized by reacting phenols and formaldehyde in the presence of an acidic catalyst to form an alkali phenolate, and then reacting with carbon dioxide gas to introduce a carboxyl group to form a polyvalent metal salt. A method for producing a color developer for recording paper. (3) A color developer for pressure-sensitive recording paper made of a polyvalent metal salt of the product obtained by reacting phenols and formaldehyde in the presence of an acidic catalyst and introducing a carboxyl group therein is fixed on a support. Color developer sheet.