JPH05147345A - Color forming paper for pressure-sensitive copy - Google Patents

Abstract

PURPOSE:To provide the title color forming paper especially excellent against a change with the elapse of time in humidity resistance and improved in printability (piling). CONSTITUTION:In color forming paper for pressure-sensitive copy wherein a color forming layer containing an org. color former is provided on a support, an alkali salt of a copolymer containing maleic acid or partial ester of maleic acid (a), diisobutylene (b) and 10-18C alpha-olefin (c) as main monomers is added to the color forming layer in an amount of 0.5-20% by wt. of the total solid of said layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colored paper for pressure-sensitive copying paper, and more particularly to a colored paper for pressure-sensitive copying paper which is excellent in moisture resistance with time and has improved printability.

[0002]

2. Description of the Related Art A pressure-sensitive copying paper has a microcapsule composition containing a microcapsule containing oil droplets in which an electron-donating organic color former (hereinafter simply referred to as "color former") is dissolved as a main component on one side of a support. And a colorant composition mainly composed of an electron-accepting colorant (hereinafter, simply referred to as a colorant) which is colored on contact with the above-mentioned color former on one surface of the support. There are middle paper coated with the microcapsule composition on the opposite side 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. It has been put to practical use as a copy set by combining medium paper and lower paper in this order. In addition, a self-coloring pressure-sensitive copying paper which is capable of pressure-sensitive recording as a single product by mixing and coating a color former and a color former on the same surface of a support is also well known as one form of pressure-sensitive copying paper.

Examples of colorants for such pressure-sensitive copying paper include inorganic colorants such as acid clay, activated clay, attapulgite, zeolite, bentonite, and aluminum silicate, and phenol-aldehyde polymers and phenol-acetylene copolymers. Organic colorants such as a phenolic polymer such as a combination, an aromatic carboxylic acid or a polyvalent metal salt thereof are known.
Of these, aromatic carboxylic acids and their metal salts have the advantage that they have a higher color-developing ability than inorganic colorants, and that the color images obtained are less likely to cause a decrease in recording density during normal file storage. There is. However, after the colored paper obtained using such a color developing agent was stored in a high humidity atmosphere, it became clear that the color developing ability was deteriorated, and even when it was stored under high humidity conditions, excellent color development was achieved. There is a demand for the development of colored paper having the ability.

When printing is performed on the coated surface of color paper,
There is still a problem of powder falling off, that is, a problem that paper dust and the like are accumulated on the printing plate to cause printing omission and blurring, and in this respect, further improvement is strongly desired.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have conducted various studies and researches in order to solve the drawbacks of the conventional color paper for pressure-sensitive copying as described above. As a result, the present invention is excellent in coloring ability under high humidity conditions and moisture resistance by adding a specific copolymer compound in the color layer of the color paper for pressure-sensitive copying paper, and at the same time, printing Another object of the present invention is to provide a colored paper for pressure-sensitive copying paper having improved suitability (piling / powder removal).

[0006]

The present invention provides a pressure-sensitive copying color paper in which a color-forming layer containing an organic color-forming agent is provided on a support, wherein (a) maleic acid or Alkali salt of a partial ester of maleic acid, (b) diisobutylene, and (c) a copolymer having a C10-C18 α-olefin as a main component monomer is 0 based on the total solid content of the coloring layer. .5
It is a colored paper for pressure-sensitive copying characterized by containing up to 20% by weight.

[0007]

The present invention provides at least (a) maleic acid or a partial ester of maleic acid in a coloring layer containing an organic coloring agent.
It has an important meaning when a specific amount of (b) diisobutylene and (c) an alkali salt of a copolymer having an α-olefin having 10 to 18 carbon atoms as a main component monomer is contained.

First, as the partial ester of maleic acid (a) constituting the copolymer, for example, methyl maleate,
Propyl maleate, iso-propyl maleate, n-butyl maleate, iso-butyl maleate, tert-butyl maleate, hexyl maleate, heptyl maleate, octyl maleate, 2-ethylhexyl maleate, nonyl maleate, Cyclohexyl maleate, dodecyl maleate, tridecyl maleate,
Those having an alkyl group having 18 or less carbon atoms such as pentadecyl maleate and octadecyl maleate, those having an aromatic group such as benzyl maleate and methylbenzyl maleate, 2-hydroxyethyl maleate, 2-hydroxybutyl maleate. Having a hydroxyl group such as 2-methoxyethyl maleate, 2-ethoxyethyl maleate, 2-butoxyethyl maleate, 2-maleate
Those having an ether bond such as phenoxyethyl, N, N'-dimethylaminomethyl maleate, N maleate
Examples thereof include those having an amino group such as -tert-butylaminomethyl, those having a glycidyl group such as glycidyl maleate, and further tetrahydrofurfuryl maleate, allyl maleate, trifluoroethyl maleate and the like.

Of these, maleic acid iso-
Propyl, n-butyl maleate, iso-maleate
Copolymers using butyl and tert-butyl maleate as monomers have excellent stability over time, such as moisture resistance, and the phenomenon of powder drop during printing, that is, paper dust, etc., builds up on the printing plate In addition, it is most preferably used because the occurrence of blurring is effectively eliminated.

Specific examples of the (c) α-olefin having 10 to 18 carbon atoms include 1-decene (having 1 carbon atom).
0), 1-dodecene (C12), 1-tetradecene (C14), 1-pentadecene (C15), 1
-Hexadecene (having 16 carbon atoms), 1-octadecene (having 18 carbon atoms) and the like can be mentioned, but α- having 10 to 18 carbon atoms
It may be an appropriate mixture of olefins and has 10 to 10 carbon atoms.
12, a mixture of 12 to 14 carbon atoms and 16 to 18 carbon atoms and the like are preferably used.

The copolymer used in the present invention includes:
In addition to the main component monomers as described above, those obtained by appropriately copolymerizing monomers such as acrylic acid, methacrylic acid, or their esters as necessary are also included.

The composition ratio of the main component monomers constituting the copolymer is (a) maleic acid or a partial ester of maleic acid, (b) diisobutylene, (c) a carbon number of 10-18.
Α-olefin of 40-50: 20-5
Copolymers in the range of 0: 5 to 30 (mol%) are particularly preferable from the viewpoint of obtaining the desired effects of the present invention.

The copolymer used in the present invention is prepared by mixing each of the above monomers in water, methanol, ethanol, isopropanol, butanol, ethyl acetate, methyl ethyl ketone, toluene, xylene, etc., alone or in a mixed solvent. Polymerization initiators such as potassium persulfate, ammonium persulfate, hydrogen peroxide, cumene hydroperoxide, iron (II), chromium ion, sulfite, hydroxylamine, hydrazine, benzoyl peroxide, azobisisobutylnitrile, etc., secondary It is synthesized by a well-known method using various polymerization aids such as a polymerization regulator such as alcohol and mercaptosuccinic acid and an emulsifier such as sodium lauryl sulfate.

The copolymer thus obtained is further neutralized with amines such as ammonia, ethylamine, propylamine, monoethanolamine, diethanolamine, triethanolamine and propanolamine, and alkalis such as sodium hydroxide and potassium hydroxide. However, it is not always necessary to neutralize all the carboxyl groups in the copolymer, and free carboxyl groups may remain. However, in order to obtain sufficient water solubility, it is necessary to neutralize so that at least 8 mol% or more of the alkali salt of carboxylic acid is present in the copolymer.

The alkali salt of the above copolymer used in the present invention generally has a concentration of 1 to 50% by weight and a pH of 3 to.
12, prepared as an aqueous solution or dispersion having a viscosity of about 1 to 100,000 cps (20 ° C.). More preferably, 20 to 5000 c in a 20% by weight aqueous solution (20 ° C.)
An aqueous solution or a water dispersion having a degree of polymerization showing a viscosity of about ps and a pH of 5 to 10 using a volatile neutralizing agent such as ammonia as a main neutralizing agent is preferable.

The mixing ratio of the alkali salt of such a copolymer to the color-agent coating layer is appropriately adjusted according to the kind of the copolymer salt used and the like, but the total solid content in the color-agent layer is not limited. 100
With respect to parts by weight, 0.5 to 20 parts by weight, preferably 1 to
It is adjusted in the range of about 10 parts by weight. By the way, if it is less than 0.5 parts by weight, the desired effect of improving the moisture resistance of the present invention cannot be obtained. On the other hand, if it exceeds 20 parts by weight, piling (powder falling off during printing) is improved. However, it is not preferable because it causes a decrease in color developability.

Further, as the organic color developing agent, a color developing agent which is publicly known and used in the field of pressure-sensitive copying paper can be appropriately used and is not particularly limited, but the following can be exemplified. 3-methyl-5
-Pentadecylsalicylic acid, 3-methyl-5-nonylsalicylic acid, 3-methyl-5-dodecylsalicylic acid, 3-
Methyl-5- (α-methylbenzyl) salicylic acid, 3-
Methyl-5- (α, α-dimethylbenzyl) salicylic acid, 3,5-di-secondary butylsalicylic acid, 3,5-
Ditertiarybutyl-6-methylsalicylic acid, 3-tertiarybutyl-5-phenylsalicylic acid, 3,5-ditertiaryamylsalicylic acid, 3-nonylsalicylic acid, 3
-5-Dinonylsalicylic acid, 3-nonyl-5-methylsalicylic acid, 3-nonyl-6-methylsalicylic acid, 3-dodecylsalicylic acid, 3-dodecyl-5-methylsalicylic acid, 3-dodecyl-6-methylsalicylic acid, 3, 5-dicyclohexyl salicylic acid, 3-cyclohexyl-5-
(Α-Methylbenzyl) salicylic acid, 3-phenyl-5
-(Α-methylbenzyl) salicylic acid, 3-phenyl-
5- (α, α-dimethylbenzyl) salicylic acid, 3-
(Α-methylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5-methylsalicylic acid, 3- (α-methylbenzyl) -6-methylsalicylic acid, 3- (α-methylbenzyl) -5-phenylsalicylic acid, 3,5-di (α
-Methylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5- (α, α-dimethylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5-bromosalicylic acid, 3- (α, 4-dimethylbenzyl) ) -5-Methylsalicylic acid,

3,5-di (α, 4-dimethylbenzyl)
Salicylic acid, 3- (α, α-dimethylbenzyl) -5-
Methylsalicylic acid, 3- (α, α-dimethylbenzyl)
-6-Methylsalicylic acid, 3,5-di (α, α-dimethylbenzyl) salicylic acid, 5- (4-mesitylmethylbenzyl) salicylic acid, benzylated styrenated salicylic acid, 2-hydroxy-3- (α, α- Dimethylbenzyl) -1-naphthoic acid or 3-hydroxy-7- (α,
Examples include magnesium, calcium, zinc, aluminum, iron, cobalt, nickel or basic salts thereof such as α-dimethylbenzyl) -2-naphthoic acid.

These may be used alone or in admixture of two or more. In addition, Japanese Examined Japanese Patent Publication 40-93
09, Japanese Patent Publication No. 42-20144, Japanese Patent Laid-Open No. 48-14.
4,6'-methylenebis (4-chloro-m-cresol) and the like phenol compounds such as those described in No. 409: phenol-aldehyde resins such as p-phenylphenol-formaldehyde resin, p-tert-butylphenol- Phenolic resins such as acetylene resins and phenolic resins such as acetylene resins and polyvalent metal salts thereof: Maleic acid-rosin resins, acidic polymers such as copolymers of styrene, ethylene or vinyl methyl ether and maleic anhydride: Japanese Patent Publication 48-8215 No. 48-82
No. 16, JP-B-52-1326 and the like, polymers of aromatic carboxylic acids and aldehydes or acetylenes and polyvalent metal salts thereof: JP-B-60-15
Carboxyl group-containing terpene phenolic resins as described in No. 9540 and the like can be mentioned. However, nonyl group, dodecyl group and the like in the above examples is a concept that also includes isononyl group, isododecyl group, etc., definition of isononyl group, isododecyl group, isopentadecyl group and the like, propylene trimer, propylene tetramer or It is defined as a substituent formed by addition of 1-butene trimer and propylene pentamer.

Among these organic colorants, aromatic carboxylic acids and their polyvalent metal salts, phenolic resins and their polyvalent metal salts, copolymers of aromatic carboxylic acids and aldehydes or acetylene, and their polyvalent metals. Salt is preferably used. Of course, these coloring agents may be used in combination of two or more kinds. The method for producing the organic colorant is not particularly limited.

If necessary, starch, casein, gum arabic, carboxymethyl cellulose,
Adhesives such as polyvinyl alcohol, styrene-butadiene copolymer latex, vinyl acetate-based latex and the like may be contained.

If necessary, inorganic pigments such as zinc oxide, magnesium oxide, titanium oxide, aluminum hydroxide, magnesium sulfate and calcium sulfate may be used in combination, and various auxiliaries known in the field of producing colored paper may be appropriately added. You can also The coating liquid thus prepared for the colorant layer is a paper, a synthetic paper, a support such as a film, an air knife coater, a blade coater, a roll coater, a size press coater, a curtain coater, a short dwell coater, etc.
It is applied and dried by using an applicator publicly known in the field of general coated paper as appropriate, and finished as a colored paper for pressure-sensitive copying paper.

[0023]

EXAMPLES The effects of the present invention will be further clarified below with reference to Examples and Comparative Examples. Of course, the invention is not limited to these examples. Unless otherwise specified, parts and% in the examples represent parts by weight and% by weight, respectively.

Examples 1 to 4 and Comparative Examples 1 to 4 [Preparation of Color Layer Coating Liquid] Aqueous dispersion of zinc 3,5-di (α-methylbenzyl) salicylate finely ground by a sand mill (solid (Concentration 25%) 20 parts, heavy calcium carbonate 70 parts, zinc oxide 10 parts, water 100 parts,
After being dispersed, 10 of polyvinyl alcohol (trade name: PVA-110 / manufactured by Kuraray Co., Ltd.) is used as a binder.
% Aqueous solution, 10 parts of carboxy-modified SBR latex [trade name: SN-307 (48%) / Sumitomo Nogatac Co., Ltd.], and 10 parts of the copolymer alkali salts shown in Table 1 are added. And dispersed to prepare eight kinds of coating liquids.

Example 5 A xylene solution containing zinc 3,5-dinonylsalicylate was emulsified and dispersed in an aqueous solution containing an emulsifier, and then,
20 parts of an aqueous dispersion of zinc 3,5-dinonylsalicylate (solid content concentration 25%) obtained by heating this dispersion to remove xylene by distillation (solid content concentration 25%), 70 parts of heavy calcium carbonate, 10 parts of zinc oxide, After mixing and dispersing 100 parts of water, polyvinyl alcohol (trade name: PVA-
110 / made by Kuraray Co., Ltd.)
Part, carboxy-modified SBR latex [Product name: SN-
307 (48%) / Sumitomo Nogatak Co., Ltd.] 10
Parts, and the copolymer alkali salts shown in Table 1 were added to prepare a coating liquid for a color layer.

[Production of Coloring Paper for Pressure-Sensitive Copying Paper] Each of the above-mentioned coloring layer coating liquids was applied to one side of a base paper having a basis weight of 40 g / m ^{2 so} that the dry weight was 6.0 g / m ^2. It was coated with a coater and dried to obtain a colored paper for pressure-sensitive copying paper.

The colored paper for pressure-sensitive copying paper thus obtained was subjected to the following quality evaluation (test), and the obtained results are shown in Table 2.

[Coloring Test] Colored paper and top paper were superposed such that the coated surfaces face each other, and the paper was passed through a super calender to develop color, and after 1 hour, the color density was measured with a Macbeth densitometer ( The larger the value, the better the color development).

[Moisture resistance test] Colored paper is exposed to high humidity (humidity 80
(% RH or more), leave it in a constant humidity machine for 72 hours, then take it out, stack the colored paper and the upper paper so that the coated surfaces face each other, and pass them through a super calender to develop the color. After 1 hour, the color density was measured with a Macbeth densitometer (the larger the value, the better the change over time).

[Piling (printability) test] Using an RI printability tester (manufactured by Meisei Seisakusho), printing ink of Tack Value 13 made by Dainippon Ink Co., Ltd. was printed three times on the coated surface of the color paper, and powder was removed. The state was sensory evaluated according to the following four-level evaluation criteria.

Evaluation Criteria ⊚: No powder falling is observed. ○: A slight powder drop is observed. Δ: Peeling off was observed and there was a problem in practical use. X: The powder was significantly removed.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

As is clear from the results shown in Table 2, all of the pressure-sensitive copying color papers of the present invention were excellent in color developability, moisture resistance, and printability (piling).

Claims (2)

[Claims] 1. A color paper for pressure-sensitive copying, comprising a color layer containing an organic color agent on a support, wherein (a) is contained in the color layer.
An alkali salt of maleic acid or a partial ester of maleic acid, (b) diisobutylene, and (c) a copolymer having a C10 to C18 α-olefin as a main component monomer is the total solid content of the color layer. The coloring paper for pressure-sensitive copying is characterized by containing 0.5 to 20% by weight. 2. The composition ratio of the main component monomers constituting the copolymer is (a) maleic acid or a partial ester of maleic acid:
(B) Diisobutylene: (c) α- having 10 to 18 carbon atoms
Olefin = 40 to 50:20 to 50: 5 to 30 (mol%), The colored paper for pressure-sensitive copying according to claim 1.