JPH07106673B2 - Method for producing colored paper for pressure-sensitive copying paper - Google Patents

Description

TECHNICAL FIELD The present invention relates to a colored paper for pressure-sensitive copying paper using an organic colorant, and particularly to a pressure-sensitive copying paper having high smoothness and strong gloss. It concerns colored paper.

"Prior Art" A pressure-sensitive copying paper has a microcapsule composition mainly composed of microcapsules containing oil droplets in which an electron-donating organic color former (hereinafter simply referred to as "color former") is dissolved on one side of a support. On the coated upper paper and one side of the support, a color former composition containing an electron-accepting color former (hereinafter simply referred to as a color former), which is colored when it comes into contact with the above color former, is applied. On the other side, there are inner paper coated with the microcapsule composition and lower paper coated with the colorant composition on one side of the support. These three types of sheets are upper paper, lower paper or upper paper, middle paper. The copy sets have been put into practical use by combining the lower sheets in this order. A self-coloring pressure-sensitive copying paper in which a color-developing agent and a color-developing agent are coated on the same surface of a support to enable pressure-sensitive recording with one sheet is also well known as one form of the pressure-sensitive copying paper.

As a colorant for such pressure-sensitive copying paper, an inorganic colorant such as acid clay, activated clay, attapulgite, zeolite, bentonite, silica, aluminum silicate and phenol-
Aldehyde polymers, phenol polymers such as phenol-acetylene polymers, and organic colorants such as aromatic carboxylic acids or polyvalent metal salts thereof are known.

Among them, the organic color former has the advantage that it has a higher color-developing ability than the inorganic colorant, and that the obtained color-developed image does not cause a decrease in recording density due to adhesion of water or ordinary file storage. On the other hand, however, the colored paper using the organic coloring agent has a drawback that the ink receptivity is not sufficient when printed on the colored paper. In recent years, pressure-sensitive copying paper has become colorful and multicolored, and therefore high smoothness is required and, at the same time, strong gloss is desired. However, at the present time, there is no pressure-sensitive copying paper which is a coloring paper using an organic coloring agent, has good ink receptivity, and has high smoothness and strong gloss. A coloring agent layer using an organic coloring agent is usually incorporated with a pigment in order to impart ink receptivity, and for example, talc is used as a part of the pigment (JP-A-63-47191). No.) is proposed. However, the colored paper obtained by this method is accompanied by a new defect that the coloring property is deteriorated.

Therefore, there is a method of using calcium carbonate as a pigment replacing talc. When calcium carbonate is used in combination, the above performance is improved and the ink receptivity when printed is also improved. However, when calcium carbonate is used as a pigment, it becomes a colored paper for pressure-sensitive copying paper having low smoothness and gloss.

The applicant of the present application has previously proposed that in a color paper for pressure-sensitive copying paper in which an organic colorant is used, calcium carbonate is contained in an amount of 50% by weight or more based on the total weight of the organic colorant and the pigment. Filed with a content of 0.1 to 1.2 .mu.m of kaolin in an amount of 5 to 30% by weight and improved rub resistance, slipperiness and ink receptivity. However, in this structure, since the amount of calcium carbonate used is large, the smoothness and glossiness are still unsatisfactory even though the above-mentioned improvement effect is obtained.

[Problems to be Solved by the Invention]

An object of the present invention is to provide an organic colored paper for pressure-sensitive copying paper, which has improved abrasion resistance, slipperiness, and ink receptivity, and further has high smoothness and strong gloss. .

[Means for Solving the Problems]

The present invention is a color paper for pressure-sensitive copying paper provided with a color layer containing an organic color agent and a pigment, wherein the color agent layer contains calcium carbonate in an amount of 15 to 45% by weight and an average particle size of 0.3 to 1.2. A method for producing a colored paper for pressure-sensitive copying paper, which comprises 15 to 45% by weight of kaolin having a diameter of μm and is supercalendered under a condition of a nip pressure of 150 kg / cm or more.

[Action]

In the present invention, the whiteness and the ink receptivity are improved by containing calcium carbonate as a pigment in the range of 15 to 45% by weight in the organic colorant layer, and the average particle size is 0.3.
~ 1.2μm kaolin is contained in the range of 15-45% by weight to improve the roughness and scratch resistance of the coated surface due to calcium carbonate blending, and super calendering is performed under a nip pressure of 150k / cm or more. As a result, it is possible to obtain a colorant for pressure-sensitive copying paper, which has high smoothness and strong gloss in relation to the above-mentioned pigment composition and at the same time has good slidability and excellent printing workability.

By the way, when kaolin is contained in the color developing agent layer, a powder falling phenomenon due to a weak bonding force between crystals in the plate-like particles is likely to occur. However, among kaolins, especially the average particle size is
If the thickness is 1.2 μm or less, this phenomenon can be prevented and the slip property can be improved. However, the average particle size of kaolin is 0.
If it is less than 3 μm, the effect of improving the slipperiness is insufficient,
Further, in order to sufficiently adhere the fine kaolin, it is necessary to increase the amount of the binder in the color-developing layer, and as a result, the ink receptivity is deteriorated. On the other hand, the average particle size is 1.2μ
Kaolin having a particle size of more than m has a drawback that the coated surface has a large roughness, and the resulting colored paper has poor rubbing resistance (so-called scorching stain). Two or more kinds of kaolin having different particle diameters and whiteness may be used in combination.

The amount of kaolin used is 15 based on the total weight of organic colorant and pigment.
~ 45% by weight, preferably 20-30% by weight. By the way, 15
If it is less than wt%, the effect of improving the slipperiness is insufficient, while
When it is used in excess of 45% by weight, whiteness and color density are reduced. Next, in the present invention, in order to impart high smoothness and strong gloss to the surface of the color developing agent layer, super calendering is applied, but the pressing condition in this case is that the nip pressure is 150 kg / cm or more. By the way, if the nip pressure is 150 kg / cm or less, high smoothness and strong gloss cannot be obtained regardless of the number of nips through which the paper passes. In the case of super calendering, the smoothness can be further improved by passing the paper with the color developing agent layer surface in contact with the chilled surface even with the same nip pressure as compared with the elastic roll surface in contact with the paper.

Examples of the organic colorant used in the present invention include:
JP-B-49-10856, JP-B-51-25174, JP-A-49-55
Benzoic acid, p-tert-, as described in No. 410, etc.
Butyl-benzoic acid, 4-methyl-3-nitrobenzoic acid,
Salicylic acid, 3-phenylsalicylic acid, 3-cyclohexylsalicylic acid, 3-tert-butyl-5-methylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 3-methyl-5-benzylsalicylic acid, 3-phenyl-5- ( α,
α-Dimethylbenzyl) salicylic acid, 3-cyclohexyl-5- (α, α-dimethylbenzyl) salicylic acid, 3
-(Α, α-Dimethylbenzyl) -5-methylsalicylic acid, 3,5-di-cyclohexylsalicylic acid, 3,5-di-
(Α-methylbenzyl) salicylic acid, 3,5-di- (α,
α-Dimethylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5- (α, α-dimethylbenzyl) salicylic acid, 4-methyl-5-cyclohexylsalicylic acid, 2
-Hydroxy-1-benzyl-3-naphthoic acid, 1-benzoyl-2-hydroxy-3-naphthoic acid, 3-hydroxy-5-cyclohexyl-2-naphthoic acid, 2-hydroxy-4-[(4-carboxy- 5-hydroxy)
Aromatic carboxylic acids such as phenyl] -1-naphthoic acid and salts thereof with polyvalent metals such as zinc, aluminum, magnesium, calcium and cobalt: JP-B-40-93
No. 09, JP-B-42-20144, JP-A-48-14409 and the like, 6,6'-methylenebis (4-chloro-
Phenol compounds such as m-cresol): phenol-aldehyde resins such as p-phenylphenol-formaldehyde resin, phenol resins such as phenol-acetylene resin such as p-tert-butylphenol-acetylene resin, and polyvalent metal salts thereof: malein Acidic polymers such as acid-rosin resins, copolymers of styrene, ethylene or vinyl methyl ether and maleic anhydride: JP 48
Polymers of aromatic carboxylic acids and aldehydes or acetylenes as described in JP-B-8215, JP-B-48-8216, JP-B-52-1326 and the like, and polyvalent metal salts thereof and the like can be mentioned.

Among these organic colorants, aromatic carboxylic acids and polyvalent metal salts thereof, phenol resins and polyvalent metal salts thereof, copolymers of aromatic carboxylic acids and aldehydes or acetylene and polyvalent metal salts thereof are particularly preferable. It is preferably used.
Two or more kinds of these coloring agents may be used in combination.

If necessary, the coating liquid may contain a binder (adhesive) such as starch, casein, gum arabic, carboxymethyl cellulose, polyvinyl alcohol, styrene / butadiene copolymer latex, and vinyl acetate latex. Also, zinc oxide, magnesium oxide,
Titanium oxide, aluminum hydroxide, magnesium sulfate,
Inorganic pigments such as calcium sulfate may be used in combination within a range that does not impair the effects of the present invention, and various auxiliaries known in the field of producing colored paper may be appropriately added.

The method for preparing the coating liquid for forming the color-developing layer is not particularly limited and may be appropriately prepared. For example, a method of coating a support with a coating liquid obtained by mechanically dispersing an organic colorant in water together with an inorganic pigment, a binder, a dispersant and other additives,
Further, a method of dissolving a color developing agent in an organic solvent and emulsifying it in water, applying a coating liquid obtained by adding an inorganic pigment, a binder, and other additives to a support, or a coating liquid obtained by mixing both A method of coating on a support is used. The organic solvent for the color developing agent is an aliphatic or aromatic ester,
Examples thereof include biphenyl derivatives, naphthalene derivatives, biphenyl alkanes and the like.

Specifically, methyl amyl acetate (1,3-dimethylbutyl acetate), 2-ethylbutyl acetate, 2
-Ethylhexyl acetate, amyl propylate,
iso-butyl-iso-butyrate, 2,2,4-trimethyl-
1,3-pentanediol monoisobutyrate, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, 2, 4-dimethyl-2,4-pentanediol diacetate, 2,2-dimethyl-1,3-butanediol diisobutyrate, 2-methyl-2,4-pentanediol dipropionate, 2,3,3,4 -Tetramethyl-2,4-pentanediol monoacetate, amyl lactate, 2-methylbiphenyl, 3-methylbiphenyl, 3,3-dimethylbiphenyl, 2,4-dimethylbiphenyl, 2,6
-Dimethylbiphenyl, 2,4,6-trimethylbiphenyl, cyclohexylbenzene, bicyclohexylbenzene, monoisopropylbiphenyl, monoisopropylnaphthalene, diisopropylnaphthalene, 1-isopropylphenyl-2-phenylethane, 1-isopropylphenyl-1-phenylethane , 1,1-ditolylethane, 1-ethylphenyl-1-phenylethane, 1-phenyl-1-xylylethane and the like. A poor solvent such as a petroleum fraction having a boiling point of 150 ° C. to 310 ° C. can be used as a diluent together with these solvents.

The coating liquid for the color layer thus prepared is applied to a support such as paper, synthetic paper or film by an ordinary coating device such as an air knife coater, a blade coater, a roll coater, a size press coater, a curtain coater or a short dwell coater. It is applied and finished as a colored paper for pressure-sensitive copying paper.

"Examples" Examples and comparative examples will be given below to further clarify the effect of the present invention, but the present invention is not limited to these examples. In addition, unless otherwise indicated, the part and% in an example represent a weight part and weight%, respectively.

Example 1 [Preparation of Coloring Agent Coating Liquid] 3,5-
12 parts of zinc di (α-methylbenzyl) salicylate, 40 parts of calcium carbonate, 18 parts of zinc oxide, 30 parts of kaolin having an average particle size of 0.8 μm, and 90 parts of water are mixed and dispersed, and a 30% modified starch aqueous solution is further used as a binder. 33 parts and carboxy-modified SBR latex (SN-307, Sumitomo Nogatac, 48% concentration)
42 parts was added to obtain a dispersion.

[Manufacture of colored paper for pressure-sensitive copying paper]

A dry weight of 10 g of the above coloring agent coating solution is applied to one side of a high-quality paper of 95 g / m ^2.
It was coated with an air knife coater so as to be g / m ² and dried. Then, while the color developing agent layer surface was in contact with the chilled surface, super calendering was performed under a condition of a nip pressure of 180 kg / cm to obtain a color paper for pressure sensitive copying paper. The quality characteristics of the obtained color developing agent layer surface are as shown in the attached table.

Example 2 [Preparation of Coloring Agent Coating Liquid] 3,5-
12 parts of zinc di (α-methylbenzyl) salicylate, 25 parts of calcium carbonate, 18 parts of zinc oxide, 45 parts of kaolin having an average particle size of 0.8 μm, and 90 parts of water are mixed and dispersed, and a 30% modified starch aqueous solution is further used as a binder. 33 parts and carboxy-modified SBR latex (SN-307, Sumitomo Nogatac, 48% concentration)
42 parts was added to obtain a dispersion.

[Manufacture of colored paper for pressure-sensitive copying paper]

A dry weight of 10 g of the above coloring agent coating solution is applied to one side of a high-quality paper of 95 g / m ^2.
It was applied with an energy knife coater so as to be g / m ² and dried. Then, while the color developing agent layer surface was in contact with the chilled surface, super calendering was performed under a condition of a nip pressure of 180 kg / cm to obtain a color paper for pressure sensitive copying paper. The quality characteristics of the obtained color developing agent layer surface are as shown in the attached table.

Example 3 A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that kaolin having an average particle size of 0.3 μm was used. The quality characteristics of the obtained color developing agent layer surface are as shown in the attached table.

Example 4 A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 2 except that 15 parts of kaolin having an average particle size of 0.4 μm and 15 parts of kaolin having an average particle size of 0.9 μm were used. . The quality characteristics of the obtained color developing agent layer surface are as shown in the attached table.

Comparative Example 1 A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that kaolin having an average particle size of 1.4 μm was used. The quality characteristics of the obtained color developing agent layer surface are as shown in the attached table.

Comparative Example 2 Example 1 except that 50 parts of kaolin having an average particle size of 0.8 μm and 20 parts of calcium carbonate were used in Example 1.
A colored paper for pressure-sensitive copying paper was obtained in the same manner as described above. The quality characteristics of the obtained color developing agent layer surface are as shown in the attached table.

Comparative Example 3 A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that kaolin having an average particle size of 0.2 μm was used. The quality characteristics of the obtained color developing agent layer surface are as shown in the attached table.

Comparative Example 4 A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that 20 parts of kaolin having an average particle size of 0.8 μm was used and 50 parts of calcium carbonate was used. The quality characteristics of the obtained color developing agent layer surface are as shown in the attached table.

Comparative Example 5 In Example 1, 60 parts of calcium carbonate and an average particle size of 0.8μ
A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that 10 parts of m kaolin was used. The quality characteristics of the obtained color developing agent layer surface are as shown in the attached table.

Comparative Example 6 A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that super calendering was performed under the conditions of a nip pressure of 140 kg / cm. The quality characteristics of the obtained color developing agent layer surface are as shown in the attached table.

[Performance comparison test] (Smoothness) A value measured by a Beck smoothness tester specified in JIS P 8119.

(Glossiness) A value measured by a 75-degree specular gloss tester specified in JIS P 8142.

(Coloring property) Colored paper and high-quality paper were overlaid so that the coated surfaces face each other, and the paper was passed through a super calender to develop color, and the color density was measured with a Macbeth densitometer after a sense of 1 o'clock (the higher the value, the higher the value. Good color development).

(Rubbing resistance; Scratch stains due to graininess on the coated surface) Laminate the colored paper and the upper paper so that the coated surfaces face each other, and rub them 5 times with a load of 4 kg / cm ² applied to the coated surface of the colored paper. The degree of color stain was visually judged.

(Sliding property) Colored paper and top paper are laminated so that the coated surfaces face each other, and the friction coefficient of both is measured with a KAYANESS MODEL D-1055 measuring machine with a thread load of 200 g and a speed of 0.5 ft /
Measured in minutes. The static friction coefficient is preferably 0.65 or less in terms of handleability.

(Ink receptivity) Printed matter printed by the J.TAPPI paper pulp test method, No. 24m "Paper gravure printability test method (printing station type)" was evaluated visually and by a magnified photograph.

"Effect" As is clear from the attached table, the color papers for pressure-sensitive copying paper of the present invention are all excellent in smoothness and glossiness, and therefore exhibit excellent suitability for multicolor printing, and color development, It also has excellent suitability for abrasion resistance, slipperiness, and ink receptivity.

Claims (1)

[Claims] 1. A coloring paper for pressure-sensitive copying paper, comprising an organic coloring agent layer, wherein 15 to 45% by weight of calcium carbonate and 15 kaolin having an average particle diameter of 0.3 to 1.2 .mu.m are contained in the coloring agent layer. ~ 45% by weight
A method for producing colored paper for pressure-sensitive copying paper, characterized in that it is contained and supercalendered under conditions of a nip pressure of 150 kg / cm or more.