JPH04163088A - Color self-forming pressure-sensitive copy paper - Google Patents

Abstract

PURPOSE:To suppress the foaming of a coating solution and to prevent the cutting of a character on a coating surface by adding polyalkylene glycol and alkyl ethylene urea to a color forming layer. CONSTITUTION:Polyalkylene glycol and alkyl ethylene urea are added to a color forming layer based on a synthetic resin film microcapsule having a solution of a color former and an org. developer in a high b.p. org. solvent encapsulated therein. Polyalkylene glycol to be used herein is a polyoxyethylene propylene glycol addition polymer or a polyoxyethylene butylene glycol addition polymer and pref. has an average MW of 1700-2500. Alkylene ethylene urea is ethylene urea having a 10-18C alkyl group and, especially, lauryl ethylene urea, oleyl ethylene urea and stearyl ethylene urea are pref. The addition amount of alkyl ethylene urea is pref. 30-80 pts.wt. per 100 pts.wt. of polyalkylene glycol.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to self-coloring pressure-sensitive copying paper, and more particularly to prevention of colored characters from being cut off and improvement of printing suitability.

[Conventional technology]

Self-coloring pressure-sensitive copying paper has basically evolved from carphoneless pressure-sensitive copying paper, and has recently been in increasing demand. Self-coloring pressure-sensitive copying paper has a layer coated with microcapsules containing an electron-donating dye (hereinafter referred to as a coloring agent) dissolved in a high-boiling solvent on one side of a support such as paper, and an electron-accepting layer. There is a method in which an acidic substance (hereinafter referred to as a color developer) is coated and laminated, and a method in which both layers are mixed and coated to form a single layer. Self-coloring pressure-sensitive copying paper can be directly printed without using a tie printer, and a large number of copies can be obtained by placing high-quality paper on top and writing or pressure printing with a ballpoint pen or dot printer. As a coloring agent, crystal violet lactone, 3
-3-bis(P-dimethylaminophenyl)naphthalite, 3-(P-dimethylaminophenyl) -3-(2-
Triallylmethane phthalide series such as methylindol-3-yl)-6-dimethylaminophthalide and acyl derivatives of benzoyl, anizoyl, and pivaloyl of methylene blue: 3-diethylamino-6-methyl-7-
Chlorofluorane, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-methyl-cyclohexylamino-6-methyl-7-anilinofluorane, 3-
There are xanthine phthalides such as ethyl-P-tolylamino-6-methyl-7-anilinofluorane,
Also used in the present invention. These color formers are high boiling point solvents such as alkylnaphthalenes typified by diisopropylnaphthalene, diallylakanes typified by 1-phenyl-1-xylylethane, alkylbiphenyls typified by isopropylbiphenyl, and other triallyldimethanes. Aromatic hydrocarbons such as alkylbenzenes, benzylnaphthalenes, diallylalkylenes, and allylindanes; Carboxylic acid ester compounds represented by dibutyl phthalate, dioctyl maleate, diethyl azelaate, etc.; tricresyl phosphate Phosphoric ester compounds represented by phosphoric acid ester compounds, vegetable oils such as castor oil, soybean oil, cottonseed oil, or their modified oils; Also used in inventions. As an inorganic color developer, acid clay, natural clay minerals such as attapulgide, activated clay obtained by lightly or moderately treating acid clay, which is a montmorillonite clay mineral, with a mineral acid, and JP-A-57-15996 There are semi-synthetic solid acids described in the publication, and organic color developers such as various phenolic compounds, novolak type phenolic resins, polyvalent metal salts of aromatic carboxylic acids, and recently proposed polyvalent metal compounds of salicylic acid resin. . As a method for producing self-coloring pressure-sensitive copying paper, first, as described above, a color former is dissolved in a high boiling point solvent, microencapsulated, coated with a binder on a support such as paper, dried, and then fine particles are added to the upper layer. Self-coloring pressure-sensitive copying paper is manufactured by applying a pulverized color developer together with a binder in a layered manner and drying it. ) can be manufactured. In addition, microcapsules containing a color former as described above and a finely ground color developer are mixed with a binder, coated and dried to produce self-coloring pressure-sensitive copying paper (single-layer type) having a single-layer type color-forming layer. There is a method of using self-coloring pressure-sensitive copying paper. Furthermore, as a unique application, a color forming agent and a color developer are each microencapsulated, mixed with a binder, applied in a laminated or single layer type, and dried to form a color forming layer. Ink (hereinafter referred to as developer ink) is printed in desired characters or graphic patterns to produce tamper-proof self-coloring pressure-sensitive copying paper. That is, both the developer ink and the self-coloring pressure-sensitive copying paper are white, and although it is not obvious that the developer ink is printed on the paper, a sprayable container filled with a solution of the color developer in a solvent (
When a color forming agent solution is sprayed from a desensitizing checker (hereinafter referred to as a desensitization checker), the color developing ink layer undergoes a color developing reaction, and if a desired printed colored image is obtained, this proves that no tampering has been done. In this case, the color developer of the self-coloring pressure-sensitive copying paper is microencapsulated, so no coloring reaction occurs, but like normal self-coloring pressure-sensitive copying paper, the color developer is crushed into pulverized particles to form a color-forming layer. If this is the case, a desensitizing checker will cause a coloring reaction, which cannot be distinguished from the coloring reaction of the developing ink. In order to apply developer ink in this way and use a desensitization checker to prove that it has not been tampered with, the developer used (for tamper-proof self-coloring pressure-sensitive copying paper) must be microencapsulated, as described above. This is a necessary condition.

[Problems to be Solved by the Invention] By the way, self-coloring pressure-sensitive copying paper is prepared by coating microcapsules containing a coloring agent and a coloring agent together with a binder in a laminated or single layer on one side of a support such as paper. uses porous pigments as color sensitizers in order to improve color density, and the slightest pressure, rubbing, etc. can cause color stains. Therefore, in order to prevent colored stains, a particle size of 10% is used as a buffering agent.
~40 μm starch or starch derivative fine powder or fiber length 2
Since a method such as an air knife coater is used in which a large amount of cellulose fiber powder (pulp powder) of 0 to 80 μm is mixed and applied with a low concentration coating liquid, the coating liquid tends to foam, and the coated surface is There are many uneven surfaces. If there are a lot of bubbles in the coating solution, the coating solution containing large and small bubbles will be transferred from the lift roll to a support such as paper during application by the coater, and when the desired coating amount is applied and dried using an air knife, the bubbles will burst. The color disappears, and the area becomes like a large pinhole and is not coated, making it impossible to obtain a colored image. This causes characters to be cut off. Furthermore, the surface coated with a large amount of buffering agent generally has many irregularities, which are further exacerbated by the bursting of bubbles, resulting in poor color ink receptivity, which is important for printing suitability, and this poses a major problem. As a measure to prevent such foaming, silicone-based,
It is effective to add so-called antifoaming agents such as mineral oil type and aliphatic amide type, and silicone type antifoaming agents containing nonionic surfactants are particularly effective, preventing characters from cutting off and improving color ink receptivity. can be achieved. However, in the case of self-coloring pressure-sensitive copying paper made of microencapsulated color formers and color developers, it is true that silicone-based, mineral oil-based, or aliphatic amide-based antifoaming agents are added to the coating solution as a foaming prevention measure. Silicone-based and mineral oil-based products have some effect, but the oily substances in the antifoam agent composition, such as silicone and mineral oil, do not mix with the coating liquid and remain as small oil dots on the coated surface. is not coated due to the coating liquid peeling phenomenon. As a result, character breakage and even unevenness are promoted, resulting in a decrease in color ink receptivity. In order to smoothly mix these oily substances into the coating solution and reduce the amount of silicone and mineral oil used, which are the main components of silicone-based or mineral oil-based antifoaming agents, in order to prevent the peeling phenomenon, the peeling phenomenon will disappear. Otherwise, the defoaming effect cannot be obtained. In addition, if a penetrant such as sodium polycarboxylate is used in combination to prevent the peeling phenomenon (this is a frequently used printing method), the suitability for offset printing, which requires dampening water, will decrease.
It is not a practical measure to suppress foaming. Here, we will again discuss the manufacturing and productivity of self-coloring pressure-sensitive copying paper. As mentioned above, the laminated type requires two coats, which requires a large amount of heat energy and electricity, and in terms of quality, the color development speed is slow because the microcapsules containing the color former and the color developer are in two layers. It is slow and the concentration is low. On the other hand, the single-layer type has the great advantage of improving operability because it only needs to be coated once, and in terms of quality, the microcapsules and color developer are close to each other and coexist, so excellent color development speed and density can be achieved with low pressure. can get. Therefore, the object of the present invention is to suppress foaming of the coating liquid in a self-coloring pressure-sensitive copying paper in which a color forming agent and a color developer are each microencapsulated, particularly a single layer type self-coloring pressure-sensitive copying paper with excellent coloring properties. It is an object of the present invention to provide a self-coloring pressure-sensitive copying paper which prevents letters from being cut off on the coated surface, improves the surface quality, and has excellent color ink receptivity during printing.

[Means to solve the problem]

As a result of extensive experiments and research, the inventors of the present invention have developed self-coloring pressure-sensitive copies that have clear characters and high color density, and are excellent in printing suitability such as color ink receptivity. succeeded in developing paper. That is, the present inventors achieved the above objective by including polyalkylene glycol and alkyl ethylene urea in a coloring layer mainly composed of synthetic resin-walled microcapsules containing a color former and an organic color developer dissolved in a high boiling point solvent. The present invention was achieved based on the knowledge that the following can be achieved. The microcapsules each containing a color forming agent and a color developing agent used in the present invention are microencapsulated by an in-situ polymerization method.
No. 66878, No. 53-84861, No. 54-499
Capsule wall membrane materials such as those described in Publication No. 84 etc. are heat-resistant and melt-resistant polyurethane, epoxy resin,
Synthetic resins include polyurea, urea-formaldehyde resin, melamine-formaldehyde resin, etc., and melamine-formaldehyde resin is particularly preferred. The organic color developer used in the present invention (dissolved in a high boiling point solvent and incorporated into microcapsules in the same manner as the color former as described above) is a novolak type phenol resin, an aromatic carboxylic acid polyvalent metal salt, , a polyvalent metal compound of salicylic acid resin. A novolac type phenol resin obtained by polycondensing a phenol derivative and a lower aldehyde such as formaldehyde is disclosed in Japanese Patent Publication No. 42-20144 or a basic patent.
For example, specifically P-octylphenol resin, P-benzylphenol resin, P-cumylphenol resin, P-
-tert-butylphenol resin and P-phenylphenol resin. Polyvalent metal salts of aromatic carboxylic acids are disclosed in Japanese Patent Publication No. 49-10856.
No. 51-25174, No. 52-1327, No. 5
1-7372, etc., but specifically, for example, 4-hydroxybenzoic acid α-phenylbenzyl ester, 4-hydroxybenzoic acid phenethyl, 4-hydroxybenzoic acid-cinnamyl ester, 4-hydroxybenzoic acid Acid-m-fluorobenzyl ester, 4,4-hydroxy-2,2'-dibutylphenyl sulfone, cinnamyl orcelinate, 5,5-methylenebis-2,
4-dihydroxybenzylic acid benzyl ester, m-phenylphenoxyethyl orselinate, bisphenol A bisP-hydroxybenzoic acid ester, 2.4-
dihydroxybenzoic acid-P-methylbenzyl ether,
2.4-dihydroxy-6-methylbenzoic acid-〇-methylbenzyl ester, 4.4-diacetyldiphenylurea, 5-P-α-methylbenzyl-α-methylbenzylsalicylic acid, 5-P-benzyl-α-methyl Benzylsalicylic acid, 3-xylyl-5-(α,α-dimethylbenzyl)salicylic acid, 3-5-di(α-methylbenzyl)
Examples include salicylic acid, 2-hydroxy-1-α-ethylbenzyl-3-naphthoic acid, and the like. Calcium, magnesium, copper, zinc, tin, barium, cobalt, etc. are used as polyvalent metal salts, and zinc is particularly effective. Polyvalent metallization of salicylic acid resin is disclosed in JP-A-63-186.
No. 729 and No. 63-254124 in detail, for example, zinc salt of 3-5-di(4-methylbenzyl)salicylic acid resin produced by reacting styrene, 0-methyl Zinc salt of 5-(4-methylbenzyl)salicylic acid resin produced by reacting styrene,
Zinc salt of 3-phenylsalicylic acid resin produced by reacting with styrene, zinc salt of 3-5-di(4-methylbenzyl)salicylic acid resin produced by reacting with benzyl chloride, and P-methylbenzyl chloride. Examples include a zinc salt of the produced 5-(α,α-dimethylbenzyl)salicylic acid resin and a zinc salt of 3-tert-butyl-5-phenylsalicylic acid resin produced by reacting 2-4-dimethylbenzyl chloride. Examples of the polyalkylene glycol used in the present invention include polyoxyethylene glycol, polyoxyethylene propylene glycol addition polymers, polyoxyethylene butylene glycol addition polymers, etc., and polyoxyethylene propylene glycol is particularly preferred. These are glycol addition polymers and polyoxyethylene butylene glycol addition polymers. Average molecular weight is 1000-300
0, particularly preferably 1,700 to 2,500. 95 to 70% of the average molecular weight is propylene glycol or butylene glycol, particularly preferably 90 to 80%.
It is. The amount of polyalkylene glycol added is 0.05 to 1 part by weight, particularly preferably 0.15 to 0.6 parts by weight, per 100 parts by weight of the water-soluble polymer as a binder. Examples of the binder used in the present invention include starch, sodium alginate, gum arabic, dextrin, glue, gelatin, casein, collagen, viscose, methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol, Examples include sodium polyacrylate and polyethylene oxide, preferably starch, casein, and polyvinyl alcohol, particularly preferably polyvinyl alcohol. If desired, a latex emulsion of hydrophobic polymers such as vinyl acetate, acrylic, styrene-acrylic copolymer, and styrene-butadiene copolymer may be used as a binder. The alkyl ethylene urea used in the present invention is an ethylene urea in which the alkyl group has 10 to 18 carbon atoms, such as decyl ethylene urea, undecyl ethylene urea, lauryl ethylene urea, tridecyl ethylene urea, myristyl ethylene urea, These include pentadecylethylene urea, cetylethylene urea, oleyl ethylene urea, and stearyl ethylene urea, and particularly preferred are lauryl ethylene urea, oleyl ethylene urea, and stearyl ethylene urea. The amount of alkylethylene urea added is 20 to 100 parts by weight, particularly preferably 30 to 80 parts by weight, per 100 parts by weight of polyalkylene glycol. In the present invention, a buffering agent is used to prevent colored stains caused by rubbing, etc., and examples of the buffering agent include fine powders of starch derivatives, evaporable liquids such as xylene, or non-evaporable liquids to remove starch odor. Non-coloring agent microcapsules containing, thermally expandable microspheres with an average particle diameter of 30 μm containing hydrocarbons with vinylidene chloride-acrylic acid ester copolymer as a capsule membrane, and polyvinyl chloride resin particles with a glass transition point (Tg) or lower. Aggregates, protruding substances such as kaolin with a diameter of 20 to 35 μm, polyurethane particles with an average particle size of 3 to 150 μm,
Examples include cellulose fiber powder, and particularly preferred are starch or starch derivative fine powder with a fiber length of 10 to 40 μm, and cellulose fiber powder with a fiber length of 20 to 80 μm. Furthermore, in the present invention, the fluidity and whiteness of the coating solution are improved, and a lubricant,
Pigments are used as color sensitizers. Examples of pigments include inorganic pigments such as talc, kaolin, calcined kaolin, natural silica, titanium oxide, and calcium carbonate; organic pigments such as synthetic silica, styrene-methacrylic acid copolymer, urea-formaldehyde condensate, and polystyrene resin. One or two pigments are selected from the group pigments, but talc,
Calcined kaolin, synthetic silica, and urea-formaldehyde condensate. The urea-formaldehyde condensate and its products used as pigments in the present invention are, for example, "Die Markrom
olekulave Chemie”149, 1st~
A. Renner's paper on page 27 (197,1) or German Published Patent Nos. 2556017 and 26412
It is described in detail in the specification of No. 18. Urea-formaldehyde condensate is 1 mol of urea and 1.3 mol of formaldehyde.
1.8 mol, particularly preferably 1.4 to 1.5 mol, in an aqueous solution under appropriate conditions. The reaction to obtain the urea-formaldehyde condensate is preferably carried out in two stages. In the first step, urea and formaldehyde follow the conventional condensation mechanism to form a low molecular weight water-soluble precondensate, and then in the second step an acid catalyst is added to promote the formation of the urea-formaldehyde condensate, The insoluble condensate obtained in the form of a white gel is diluted to p87 with ammonia or sodium hydroxide.
~9, preferably adjusted to pH 7.5, filtered, centrifuged or steam dried to produce an insoluble fine granular powder. Furthermore, the present invention can be made into a self-coloring coating solution for a coloring layer for pressure-sensitive copying paper together with a preservative, a pH adjuster, and a fluorescent dye if desired, and coated onto a support such as paper using an air knife coater or the like.
Coat and dry to obtain ~20 g/rd (dry weight solid content). A particularly preferable coating amount is 8 to 12 g/I.

【Example】

Hereinafter, preferred embodiments and excellent effects of the present invention will be specifically explained using the most typical examples. Note that all parts below are parts by weight, and all % represents weight %. Example 1 [Method for creating synthetic resin wall microcapsules with 40% color former] 95 parts of high-boiling hydrocarbon oil, phenylxylylethane (Japan Petrochemical Type 5AS-296), 5 parts of color former: crystal violet lactone (CVL) After partially heating and melting,
5% styrene maleic anhydride copolymer aqueous solution (pH 4,
8) A coloring agent solution was added to 120 parts of the mixture while stirring at high speed, and the mixture was emulsified at a liquid temperature of 6°C so that the average particle size was 4 μm. Add 12.5 parts of melamine and 16.1 parts of a 37% formaldehyde aqueous solution to 60 parts of water, heat and dissolve at pH 9.5 to obtain a melamine-formaldehyde initial condensate, add to the above emulsion and heat at 75°C with stirring. After reacting for 2 hours, the pH of the solution was adjusted to 8.5 at a temperature of 40° C. or below, and microcapsules containing 40% color former were prepared. [Method for making synthetic resin wall microcapsules with a built-in 40% organic color developer] An organic compound is added to a mixture of 72 parts of high-boiling hydrocarbon oil 5AS-296 and 24 parts of diisopropylnaphthalene (KMC-113 manufactured by Kureha Chemical Co., Ltd.). After heating and dissolving 64 parts of novolac type P-phenylphenol resin as a color developer, 5% styrene maleic anhydride copolymer aqueous solution (pH 4,8) 240
While stirring at high speed, add the developer solution and bring the solution temperature to 6.
It was emulsified at 0°C so that the average particle size was 2.5 μm. Add 16 parts of melamine and 30 parts of a 37% formaldehyde aqueous solution to 45 parts of water, dissolve by heating at pH 9.5, and dissolve the melamine.
Obtain a formaldehyde initial condensate and add it to the above emulsion,
After reacting for 2 hours at 75° C. or higher with stirring, the pH was adjusted to 8 to 8.5 at a liquid temperature of 40° C. or lower to prepare microcapsules containing a 40% organic color developer. [Method for preparing 10% urea-formaldehyde condensate dispersion] Urea-formaldehyde condensate 100 parts 10% sodium polyacrylate aqueous solution 50 parts Water 850 parts The above mixture was ground with a ball mill so that the average particle size was 4 μm, A 10% urea-formaldehyde condensate dispersion was prepared. 80 parts of wheat starch with an average particle size of 20 μm and 3 parts of talc were added to 322 parts of water, and after dispersion and mixing, 170 parts of a 10% urea-formaldehyde condensate dispersion, 75 parts of microcapsules containing a 40% color former, and 40% organic 100 parts of microcapsules with built-in color developer, 2 parts of 10% polyvinyl alcohol aqueous solution
00 parts, 10% polyoxyethylene propylene glycol addition polymer (average molecular weight 1000. Average molecular weight 95
% propylene glycol) and 0.01 part of a 20% stearyl ethylene urea aqueous dispersion were gradually dispersed and mixed in order to obtain a coating solution for a coloring layer. This coating liquid was applied to high-quality paper with a basis weight of 50 g/m using an air knife coater so that the coating amount was 8 g/rd (dry weight solid content).
A self-coloring pressure-sensitive copying paper was prepared. Example 2 The amount of the 10% polyoxyethylene propylene glycol addition polymer aqueous solution of Example 1 was increased from 0.1 part to 2 parts, and further 2 parts.
A self-coloring pressure-sensitive copying paper was prepared in the same manner except that the amount of the 0% stearyl ethylene urea aqueous dispersion was increased from 0.01 part to 1 part to form a coloring layer coating solution. Example 3 20% stearyl ethylene urea aqueous dispersion of Example 1.
A self-coloring pressure-sensitive copying paper was prepared in the same manner except that the coating solution for the coloring layer was increased from 01 parts to 1 part. Example 4 20% stearyl ethylene urea aqueous dispersion of Example 1.
A self-coloring pressure-sensitive copying paper was prepared in the same manner except that the same amount of 20% decyl ethylene urea aqueous dispersion was used as the coating solution for the coloring layer. Example 5 0.1 part of the 10% polyoxyethylene propylene glycol addition polymer aqueous solution of Example 1 was mixed with 10% polyoxyethylene butylene glycol addition polymer (average molecular weight 170
A self-coloring pressure-sensitive copying paper was prepared in the same manner except that the coating solution for the coloring layer was replaced with 0.1 part of an aqueous solution (butylene glycol having an average molecular weight of 75%). Comparative Example 1 10% polyoxyethylene propylene glycol addition polymer aqueous solution of Example 1 0. A self-coloring pressure-sensitive copying paper was prepared in the same manner except that 1 part and 0.01 part of the 20% stearyl ethylene urea aqueous dispersion were used as a coating solution for the coloring layer. Comparative Example 2 20% stearyl ethylene urea aqueous dispersion of Example 1 0.
A self-coloring pressure-sensitive copying paper was prepared in the same manner except that part 01 was used as a coloring layer coating solution. Comparative Example 3 10% polyoxyethylene propylene glycol addition polymer aqueous solution of Example 1 0. A self-coloring pressure-sensitive copying paper was prepared in the same manner except that one part was used as a coating solution for a coloring layer. Comparative Example 4 20% stearyl ethylene urea aqueous dispersion of Example 1 0.
A self-coloring pressure-sensitive copying paper was prepared in the same manner except that the same amount of 20% nonylethylene urea aqueous dispersion was used as the coating solution for the coloring layer. (Test method) ◎Evaluation of color development speed and color cutoff The prepared self-coloring pressure-sensitive copying paper was passed through a supercalender to develop color, and the color density after 1 hour was measured using a color difference meter, and the following values were determined. The smaller the value, the higher the color density. Furthermore, when characters were printed using a dot printer, we visually observed the breakage of colored characters.Reflectance of colored area Color density (%) = X100Reflectance of white area The color ink was 5CRT7 grass (manufactured by Toyo Ink ■), and each sheet was printed on 394 mm wide rolls of self-coloring pressure-sensitive copying paper at a printing speed of 150 m/min using a Miyakoshi Seisakusho "Myaster 18" offset printing machine (spray type dampening water). After printing for 4000 m, the color ink receptivity on the printed surface was observed using a magnifying glass.Measurement of color density, colored character breakage, and color ink receptivity for Examples 1 to 4 and Comparative Examples 1 to 3 The evaluation results are shown in Table 1. Table 1. Measurement and evaluation results ○ mark: Excellent effect △ mark: Effective × mark: Inferior

【Effect of the invention】

As is clear from the present invention, the color forming layer mainly composed of the synthetic resin wall microcapsules with a built-in color former and the synthetic resin wall microcapsules with a built-in organic color developer of the present invention contains polyalkylene glycol and alkyl ethylene urea. As a result, it was possible to provide a self-coloring pressure-sensitive copying paper with excellent surface quality, clear colored characters produced by pen pressure, printer, etc., and high color density, as well as excellent color ink receptivity during printing.

Claims (1)

[Claims] 1. Consisting of a color-forming layer whose main components are synthetic resin-walled microcapsules containing an electron-donating dye and synthetic resin-walled microcapsules containing an electron-accepting acidic substance; A self-coloring pressure-sensitive copying paper characterized by containing alkylene glycol and alkyl ethylene urea. 2. The self-coloring pressure-sensitive copying paper according to claim 1, wherein the electron-accepting acidic substance is an organic acidic substance. 3. Claim 1 or 2, wherein the polyalkylene glycol is a polyoxyethylene propylene glycol addition polymer or a polyoxyethylene butylene glycol addition polymer.
Self-coloring pressure-sensitive copying paper as described. 4. The alkyl group of the alkylethylene urea has 10 carbon atoms
The self-coloring pressure-sensitive copying paper according to claim 1, 2 or 3, which is an integer of 18 to 18.