JPH01160678A - Color developer for pressure-sensitive recording paper and color developing sheet using said color developer - Google Patents

Abstract

PURPOSE:To obtain a color developing sheet for pressure-sensitive recording paper remarkably superior in shelf stability and having a good color forming properties and little possibility of yellowing even under the exposure to sunlight, by using a resol-type modified phenol resin obtained by specific materials and procedures as a color developer for pressure-sensitive recording paper. CONSTITUTION:A resol-type modified phenol resin can be produced by the reaction of a polyvalent metal salt of salicylic acid and a phenol group with a formaldehyde in such a manner that a compound of a material is heated to a temperature of 40-100 deg.C, preferably 85-100 deg.C, for 3-30 hours, preferably 5-20 hours, in a water or an organic solvent of a methanol, a toluene, or the like in the presence of an alkali catalyst, thereafter being dehydrated or solvent-removed under normal pressures or vacuum. A color developer for pressure-sensitive recording paper made of the resol-type modified phenol resin provides a color developing sheet for pressure-sensitive recording paper remarkably superior in shelf stability having good color forming properties and no possibility of yellowing even under the exposure to sunlight.

Description

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

(Prior Art) Pressure-sensitive recording paper has been known for a long time from U.S. Pat. No. 2.712.507, U.S. Pat. It is based on the fact that microcapsules containing a colorless donor coloring agent are destroyed by pressure, and the coloring agent reacts with an electron-accepting/accepting color developer to develop color.

As the next color developer for producing such pressure-sensitive recording paper, inorganic solid acids such as acid clay, activated clay, athanol, kaolin, zeolite, etc., Tumerac type phenolic resin, and Japanese Patent Publication No. 42 A p-substituted phenol-formaldehyde resin disclosed in Japanese Patent Publication No. 20144, and an aromatic carmenic acid metal salt as disclosed in Japanese Patent Publication No. 49-10856 and Japanese Patent Publication No. 52-1327 are used.

However, inorganic solid acids have a color-forming reaction rate (color-forming property)
Although it is good, the stability of the colored image against moisture and light is poor. Furthermore, Tumelac-type phenolic resins and p-substituted phenol-formaldehyde resins tend to yellow when exposed to sunlight and stored in a cool dark place, resulting in poor storage stability. There is a problem that it is inferior. In addition, aromatic cardanate metal salts.

Another problem is that when the resulting colored image comes into contact with water or a plasticizer, the sharpness decreases significantly, and the water resistance and plasticizer resistance are poor.

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

Therefore, the object of the present invention is to provide a color developer sheet for pressure-sensitive recording paper that exhibits good color development and has excellent storage stability, with almost no yellowing even when exposed to sunlight, and its color developer. The object of the present invention is to provide a color developer that provides a sheet.

(Measures and Actions to Solve the Problem) The present inventors have achieved the above-mentioned objective by using a resol-type modified phenolic resin obtained using specific raw materials and procedures as a color developer for pressure-sensitive recording paper. The present invention was achieved by discovering that the following can be achieved.

That is, the present invention provides a color developer for pressure-sensitive recording paper comprising a resol-type modified phenolic resin obtained by reacting a polyvalent metal salt of salicylic acid and a phenol with formaldehyde in the presence of an alkali catalyst, and a color developer for pressure-sensitive recording paper. This invention relates to a color developing sheet fixed on a support.

The polyvalent metal salt of salicylic acid used in the present invention includes:
Salicylic acid and e.g. zinc, magnesium, cadmium,
Salts with polyvalent metals such as aluminum, lead, titanium, calcium, cobalt, nickel and manganese may be mentioned. Among these, zinc salts are preferred from a practical standpoint.

Examples of the phenols used in the present invention include evaphenol; cresol, ethylphenol, n-propylphenol, isopropylphenol, n-butylphenol, isobutylphenol, tert-butylphenol, n-amylphenol, isoamylphenol, 1,1 -dimethyl-n-propylphenol, n-hexylphenol, isohexylphenol, 1.1-
dimethyl-n-butylphenol, 1,2-dimethyl-
n-butylphenol, n-hebutylphenol.

isohebutylphenol, 5.5-trimethyl-n-amylphenol, n-octylphenol.

1.1,3.3-tetramethylbutylphenol, isooctylphenol, nonylphenol, 1.1.3.
Alkylphenols such as 3-tetramethylamylphenol, n-decylphenol, isodecylphenol, n-undecylphenol, inundecylphenol, n-dodecylphenol; Arylphenols such as phenylphenol and naphthylphenol: penzylphenol Examples include arylalkylphenols such as dichlorohexylphenol, cycloalkylphenols such as dichlorohexylphenol, and resorcinol. Preferred among these are phenol, cresol, nographenylphenol and other para-substituted alkylphenols.

As the formaldehyde used in the present invention, formalin, which is an aqueous formaldehyde solution, is practical.

Examples of the alkali catalyst include alkali metal oxides and hydroxides, alkaline earth metal oxides and hydroxides, salts of these with weak acids such as carbonic acid, and amines. Two or more types are used. Its usage is
Usually, the amount is in the range of 0.5 to 10% by weight based on the total amount of the polyvalent metal salt of salicylic acid and the phenol.

In the present invention, in order to produce a resol-type modified phenolic resin by reacting a polyvalent metal salt of salicylic acid and phenols with formaldehyde, the raw material compound is mixed in water or an organic solvent such as methanol or toluene in the presence of an alkali catalyst. 40-100℃, preferably 85-100℃
After heating at a temperature of 3 to 30 hours, preferably 5 to 20 hours, dehydration or solvent removal may be carried out under normal pressure or reduced pressure.

There is no particular restriction on the proportion of the raw material compounds used, but the amount of the polyvalent metal salt of salicylic acid used is normally in the range of 0.05 to 20 moles, preferably 0.1 to 1 mole, per mole of phenol. It is. Further, the proportion of formaldehyde to be used is usually 1 to 3 mol, preferably 1.2 to 3 mol, relative to the total of 111 mol of the polyvalent metal salt of salicylic acid and phenols.
The range is 2.5 moles.

The thus obtained resol-type modified phenolic resin contains methylol groups that are not present in the tumelac-type phenolic resin and p-substituted phenol-formaldehyde resin, which are commonly used as color developers for conventional pressure-sensitive recording paper. They are structurally completely different. Then,
4 due to proton orchid, which is not observed in conventional color developers.
, found in 8-nor resin. In addition, in the proton NMR chart of the conventional color developer, the methylene group <3
．． The peak at the 8 ppm position is noticeable.

The nine color developers obtained in the present invention can be used alone, but other known color developers can be used, such as inorganic solid acids such as activated clay, phenolic resins, p-substituted phenol-formaldehyde resins, aromatic carmenes, etc. It can also be used in combination with acids and their metal salts.

In the present invention, a color developer sheet is prepared using a color developer for pressure-sensitive recording paper made of a resol type modified phenolic resin.
The color developer may be fixed on a support such as paper or plastic film using a binder. For example, it is dissolved or suspended in an aqueous dispersion of a color developer or an organic solvent, and the following is mixed with a binder such as starch, synthetic rubber, or natural rubber latex, along with fillers such as caolin, clay, and calcium carbonate as necessary, and applied. A color developer sheet is obtained by preparing a liquid, coating it on a support, and drying it. In general, the amount of the coating liquid is 2 to 1017 m'' in terms of solid content.

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
-dimethylaminephenol)-6-trimethylaminophthalide (crystal violet lactone), 3.
3-bis(p-dimethylaminephenol)7thallide (
Diarylphthalides such as malachite green lactone): N-(2,3-dictetralophenyl)-+, +
Leukoauramines such as eucoauramine; acylodiamines such as N-benzoyluramine and N-acetylauramine; arylauramines such as N-phenylauramine; dianilideneacetone, dibenzylideneacetone, anisylidene bases such as α,β-unsaturated aryllactone-dimethylaminoazobenzene-〇-cal Moxy acid (methyl red) such as acetone, 4-aminoazobenzene (oil yellow AAB), 4-phenylazo-1-knuckleamine; Rhodamine B lactams such as N-(p-nitrophenyl)-Rhodamine B lactam: Polymers such as bis(p-dimethylaminophenyl)-methanol, crystal violet carbinol, malachite green carbinol Arylcarbinols 28'-methoxy-benzoindolinospiropyran, 4,7.8'-
Trimethoxy-benzoindolinospiropyran, 6'-
8'-Methoxy-benzoindolinospiropyrans such as chloro-8'-methoxy-benzoindolinospiropyran: Used in combination with a coloring agent such as p-dimethylaminostyrylquinoline.

(Effects of the Invention) The color developer for pressure-sensitive recording paper made of the resol-type modified phenolic resin of the present invention has excellent color development properties and does not yellow even when exposed to sunlight, and has excellent storage stability and stability. This product provides a color developing sheet for pressure-sensitive recording paper. Matsugi,
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 resulting colored image is stable.

(Example) The present invention will be explained below with reference to Examples. Note that the percentages in the examples are based on weight.

Example 1 1381 p-phenylphenol and 80% zinc salicylate were added to 11 seven-parameter flasks equipped with a thermometer, stirrer, and reflux condenser. P, 156.9% of 37% formalin and 20.9% of 28% aqueous ammonia were prepared and heated to 12% at reflux temperature.
Nine hours to react. Afterwards, it is dehydrated under reduced pressure to form a solid resin (
1) got nine.

Example 2 P-
Nonylphenol 360g, zinc salicylate 15013
Charge 330.9 g of 7% formalin and 20.9 g of 48% aqueous sodium hydroxide solution.

The reaction was then carried out at reflux temperature for 12 hours. Then dehydrated under reduced pressure.
Obtain solid resin (2).

Example 3 The same Nananoya rubble flask KP- as used in Example 1
Tertiary octylphenol 135N.

Zinc salicylate 60, 140 g of 9.37% formalin and 151 I of 28% ammonia water were charged and reacted at reflux temperature for 12 hours. Thereafter, it was dehydrated under reduced pressure to obtain a solid resin (3).

Comparative Example 1 P-
Phenylphenol 2009. ) 200 # of toluene and 10.9 # of 20% hydrochloric acid were charged and heated until the liquid temperature reached 90°C. 37% formalin 55J while paying attention to fever.
F was added and kept at 90°C for 6 hours. Thereafter, the solvent was removed under reduced pressure to obtain a solid comparative resin (1).

Comparative Example 2 P-
Tertiary-butylphenol 170g, toluene 20g
Prepare 10g of 0.9 and 20% hydrochloric acid, and bring the liquid temperature to 90℃.
heated until. Processed with 37% formalin (5.1 M't) and kept at 90°C for 6 hours while being careful not to generate heat. Then, the solvent was removed under reduced pressure.

A solid comparative resin (2) was obtained.

Example 4 Resin (1) obtained in Examples 1 to 3 and Comparative Examples 1 to 2
-(3) and comparative resins (11-(2)) were used as color developers and dispersed in water with a sand mill to prepare an aqueous dispersion of color developer with the following composition.

Composition of aqueous dispersion of color developer Color developer: 30 parts by weight DISCO)
N14 (manufactured by Kao ■) 3 parts by weight water
80 parts by weight Next, using each of the aqueous dispersions of the color developer, a coating liquid of the color developer was prepared with the composition shown below.

Composition of color developer coating solution Aqueous dispersion of color developer 70 parts by weight Calcium carbonate 90 parts by weight 50% Styrene-butadiene pumice latex is parts by weight Oxidized starch 20 parts by weight Each of the resulting color developer coating liquids After applying it to high-quality paper to a solid content of 797 m'', it was dried to create a color developing sheet.

Each of the resulting color developing sheets and business "e-tsuku-"
9. The performance of the color developing sheet is evaluated by the method shown below using a color developing sheet coated with color forming agent-containing microcapsules manufactured by Supply Co., Ltd. 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 placed one on top of the other, three characters were printed using an electric typewriter, and the clarity of the characters on the color developer sheet was observed. ◎→O→Δ 3 in descending order of clarity
Next, graded evaluation.

(21 Exposure of a color developing sheet that has not undergone solar yellowing to direct sunlight for 2 days, and measure the b value before and after exposure to sunlight with a Minolta colorimeter CR-100. The difference in b value before and after exposure to sunlight is as follows. The larger the Δb value, the more significant the yellowing.

(3) Plasticizer Resistance (1) Color is developed using the color development method. After storing the color development sheet in a cool and dark place for 24 hours, dioctyl phthalate is applied to the color development sheet, and the clarity of the characters after 10 minutes. The images were observed and evaluated in three stages: I@, ◎ → ○ → Δ, from the most vivid.

(4) Resistance to nitrogen oxide yellowing Leave the uncolored developing sheet 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 Minolta color difference meter CR-100.

The larger the Δb value, the more significant the yellowing.

Table 1

Claims (1)

[Claims] 1. A color developer for pressure-sensitive recording paper comprising a resol-type modified phenolic resin obtained by reacting a polyvalent metal salt of salicylic acid and phenols with formaldehyde in the presence of an alkali catalyst. 2. A developer prepared by fixing on a support a color developer for pressure-sensitive recording paper consisting of a resol-type modified phenolic resin obtained by reacting polyvalent metal salts of salicylic acid and phenols with formaldehyde in the presence of an alkali catalyst. color sheet.