JPS61173986A - Pressure sensitive copying paper - Google Patents

Abstract

PURPOSE:To improve color-forming speed, formed color density, sun-resistance stability of color-formed image, sun-resistance stability of color-developing surface, plasticizer-resistance stability of color-formed image, etc. by using baked clay calcium carbonate-blended inorg. pigment, and phenol-polymerized coloring agent. CONSTITUTION:A high oil-absorption phenyl copolymer color-developing layer having chemical stability to sun and plasticizer is considered to be formed by an inorganic pigment formulated with baked clay calcium carbonate. That is, it is considered that the formation of such a developing layer is due to the improvement effect of a color-forming physical constitution and the involved development effect of a chemical stability of the phenol copolymer developer layer by a formulated inorganic pigment of baked clay calcium carbonate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to pressure-sensitive copying paper, particularly pressure-sensitive copying paper that is excellent in color development speed, color development density, sun resistance, and plasticizer resistance.

(Prior art) Generally, pressure-sensitive copying paper consists of a sheet (top paper) coated with microcapsules containing an electron-donating color former dissolved in an organic solvent on the bottom surface, and an electron-accepting color developer coated on the top surface. A sheet (middle sheet) coated with 'my microcapsules on the bottom surface and an electron-accepting color developer on the top surface is suitably superimposed between the sheet (bottom sheet) and the sheet (middle sheet), depending on the number of copies to be made. When you apply writing pressure, typing pressure, etc. to the top surface of pressure-sensitive copy paper,
The microcapsules at the bottom of the pressure are destroyed, and the electron-donating color former is transferred from the opposing contact surface to the developer layer, forming a colored ash with the electron-accepting developer, which is the mechanism by which copies are obtained ( For example, U.S. Pat. No. 2,730,456) d Electron-donating coloring agents used in pressure-sensitive copying paper include triphenylmethane, phthalide-based crystal violet lactone, and phenothiazine-based benzoylleucomethylene blue. The coacervation method that utilizes the phase separation phenomenon of polymer solutions (for example, U.S. Pat. No. 2,800,457), and the interfacial polymerization method that utilizes the formation of polymers at the interface of emulsified fine particles (for example, Japanese Patent Publication No. 42
-446, Special Publication No. 42-771), 1n-8itu
Polymerization method (Japanese Patent Publication No. 36-9168), etc. is generally used.

(Problems to be Solved by the Invention) Electron-accepting color developers used in pressure-sensitive copying paper include clay materials such as activated clay, acid clay, and attapulgite (for example, Japanese Patent Publication No. 41-7622, U.S. Pat. 712507)
, polyvalent metal salts of aromatic carboxylic acids and their derivatives (e.g., Japanese Patent Publication No. 49-10856, Japanese Patent Publication No. 52-1327), phenol polymers (e.g., Japanese Patent Publication No. 42-20144).
@ etc. are said. However, clay materials have a long shelf life,
Polyvalent metal salts of aromatic carboxylic acids and their derivatives improve sunlight resistance, plasticizer resistance, etc. of color images and color development ability, and phenol polymers improve color image resistance, plasticizer resistance, etc. There are drawbacks in terms of sunlight resistance, resistance to sunlight yellowing on the developing surface, resistance to plasticizers, etc. Furthermore, there is still a need for improvement in terms of color development density in the case of these inorganic color promoters and color development speed in the case of organic color developers.

(Means for solving the problem of confusion) The purpose of the present invention is to significantly improve color development speed, color density, color image, sunlight resistance stability, color development surface sunlight resistance stability, color image resistance to plasticizers, etc. An object of the present invention is to provide an improved pressure-sensitive copying paper.

The objects of the present invention are achieved by using a calcined clay-calcium carbonate blended inorganic pigment and a phenolic polymer color developer.

The blending ratio of the blended inorganic pigments is in the range of 5 to 95 parts by weight of fired clay and 95 to 5 parts by weight of calcium carbonate, and the total amount of both inorganic pigments is 100 parts by weight. Particularly preferred is 20 to 60 parts by weight of calcined clay and 6 parts by weight of calcium carbonate.
The range is from 0 to 20 double notes.

The fired clay used in the present invention is an inorganic pigment with a bulky particle structure in which fine hexagonal plate-shaped clay particles are sintered.
Calcium carbonate includes well-known precipitated calcium carbonate, wet-ground ground calcium carbonate, dry-ground ground calcium carbonate, and the like.

The phenol polymer used in the present invention is an oil-soluble novolak type polymer obtained by reacting phenols such as paraphenylphenol and paraallylphenol with aldehydes under acidic conditions. For example, phenols include (1) phenol, (z) p-alkylphenol such as p-luzole, p-ethylphenol, p-butylphenol, p-octylphenol, p-nonylphenol, p-dodecylphenol, (3) I) -p-cycloalkylphenol such as cyclohexylphenol,
(4) p-allylphenol such as p-phenylphenol, (5) I)-α-methylbenzylphenol, p-
p-aralkylphenol such as α,α-dimethylbenzylphenol, (6) p-chlorophenol, p
-p- such as fluorophenol and p-bromophenol
These include halogenated phenols and p-aryloxyphenols such as ('y)p-phenoxyphenol, and examples of aldehydes include formaldehyde and acetaldehyde. Furthermore, so-called metal salt-modified phenol polymers obtained by modifying the above-mentioned phenol polymers with zinc, manganese, etc. can also be used.

(Function) When a 6-single inorganic pigment of calcined clay is used for a phenol polymer color developer, the desired strong print surface change cannot be obtained. Further, problems such as poor fluidity of the coating solution arise. On the other hand, when a single inorganic pigment of calcium carbonate is used, there are problems with color development speed, color development density, light resistance, etc. However, when a blended inorganic pigment of calcined clay calcium carbonate is used as in the present invention, the drawbacks that occur in the case of the single-system inorganic pigment are solved, and the coloring speed, coloring density, light resistance, and plasticizer resistance are improved. It is possible to obtain pressure-sensitive copying paper with significantly improved properties.

The reason for the effect of the present invention is not clear, but the inorganic pigment blended with calcined clay and calcium carbonate has high oil absorption that cannot be obtained with each single inorganic pigment, and is chemically stable to the mouth and plasticizers. It is thought that a phenolic polymer color developer layer is formed. In other words, this is considered to be a synergistic effect of improving the color-forming structure and chemical stability of the phenol polymer color developer layer by the inorganic pigment blended with the calcined clay calcium carbonate.

, (Example) Next, the present invention will be explained in more detail with reference to examples, but the present invention is of course not limited to these.

Note that in the examples, "part" and "part" indicate "part by weight" and "% by weight," respectively.

Example 1 30 parts of calcined clay (manufactured by Anglo American Clay Co., Ltd., trade name Alphatex) was dispersed in 80 parts of water in which 0.03 part of sodium polyacrylate was dissolved to obtain a slurry. To this was added 117 parts of Calcilla carbonate 1 ml 0 slurry (Shiraishi Kogyoten, trade name Brillian 1-315), and the mixture was thoroughly stirred to obtain an inorganic pigment slurry. 2 for this
50 parts of 0% starch solution, 20 parts of 50% styrene-butadiene copolymer latex, 4 parts of rose phenylphenol resin
0% 1 aqueous emulsion (manufactured by Mitsui Toatsu, trade name RBE-
40) 50 parts were sequentially added and thoroughly stirred to obtain a coating liquid. This coating liquid was applied to a base paper of 40N7m'' so that the absolute dry coating amount was 597m2, and dried to obtain a lower paper.

, Example 2 30 parts of calcined 2-lay (manufactured by Engelhard, trade name: Unseelex) was dispersed in 30 parts of water in which sodium polyacrylate O and Oa parts were dissolved to obtain a slurry. 117 parts of a 60% calcium carbonate slurry was added thereto and sufficiently stirred to obtain an inorganic pigment slurry. Thereafter, a lower paper was obtained in the same manner as in Example 1.

Example 3 40 parts of calcined clay (Alphatex) was dispersed in 40 parts of water in which 0.04 part of sodium polyacrylate was dissolved to obtain a slurry. This includes 60% calcium carbonate.
100 parts of the slurry was added and thoroughly stirred to obtain an inorganic pigment slurry. Thereafter, a lower paper was obtained in the same manner as in Example 1.

Example 4 40 parts of calcined clay (Unseelex) was dispersed in 40 parts of water in which 0.04 part of sodium polyacrylate was dissolved to obtain a slurry. 100 parts of a 60% calcium carbonate slurry was added thereto and sufficiently stirred to obtain an inorganic pigment slurry. Thereafter, a lower paper was obtained in the same manner as in Example 1.

Comparative Example 1 167 parts of calcium carbonate 60% slurry was used in an inorganic pigment slurry. Thereafter, a lower paper was obtained in the same manner as in Example 1.

Comparative Example 2 100 parts of calcined clay (Alphatex) was dispersed in 100 parts of water in which 0.1 part of sodium polyacrylate was dissolved to obtain an inorganic pigment slurry.

75 parts of 20% starch solution, 30 parts of 5 oz. styrene-butadiene copolymer latex, 5 parts of 40% aqueous emulsion of rose phenylphenol resin (RBE-40)
0 parts were sequentially added and thoroughly stirred to obtain a coating liquid. Thereafter, a lower paper was obtained in the same manner as in Example 1.

Here, in this comparative example only, the amount of starch and latex was increased in order to provide the lower paper with appropriate printing surface strength similar to the other examples and comparative examples.

The coloring speed, coloring density, coloring image sunlight resistance, coloring surface sunlight resistance, and coloring image plasticizer resistance of each base paper produced in Examples 1 to 4 and Comparative Examples 1 and 2 above were tested. It was done using the missing method.

(1) Coloring speed and coloring density Each lower paper produced in Examples 1 to 4 and Comparative Examples 1 to 2 was
In combination with commercially available top paper (Daio Paper Co., Ltd., trade name Micro Chemical Paper 40A), an electric typewriter
Continuous type printing was performed using a constant pressure, and judgment was made visually.

(2) Colored Image Sunlight Stability The test piece prepared in (1) was exposed to direct sunlight for two weeks, and fading of the colored characters was visually judged.

(8) Sunlight stability of the developing surface Each of the base papers produced in Examples 1 to 4 and Comparative Examples 1 to 2 was exposed to direct sunlight for two weeks, and the yellowing of the developing surface was visually determined.

(4) Colored image plasticization resistance and agent stability A vinyl chloride film was superimposed on the test piece prepared in (1) and left under a pressure of 10 kg/m2 for one month, and the decolorization of the colored characters was visually judged. . The results of the first test were as shown in Table 1 below.

, (Effect) As is clear from Table 1, the phenol polymer color developer i
When using a blended inorganic pigment of calcined clay calcium carbonate, compared to a single inorganic pigment, the color development speed, color density, color image resistance mouth stability, color development surface sunlight resistance stability, and color image resistance plasticizer resistance are improved. A pressure-sensitive copying paper with outstanding stability could be obtained.

Claims (1)

[Claims] 1. In pressure-sensitive copying paper coated with an electron-accepting color developer,
A pressure-sensitive copying paper comprising a fired clay-calcium carbonate blended inorganic pigment and a phenol polymer color developer. 2. The pressure-sensitive copying according to claim 1, which contains 5 to 95 parts by weight of calcined clay and 95 to 5 parts by weight of calcium carbonate as blended inorganic pigments, and the total amount of both inorganic pigments is 100 parts by weight. paper.