JPS6337985A - Color developing paper for pressure sensitive copying paper - Google Patents

Abstract

PURPOSE:To improve initial color forming properties, light resistance, and printability, by a method wherein a polyvinyl alcohol and a crosslinking agent therefore are used each in a specific ratio in an adhesive for an organic color developer. CONSTITUTION:As the component of an adhesive, a polyvinyl alcohol is used 5-120wt% to an organic color developer and also a crosslinking agent is used 0.5-100wt% to the polyvinyl alcohol. As the organic color developer, an aromatic carboxylic acid, a phenol resin, a copolymer of aromatic carboxylic acid and either aldehyde or acetylene, and a polyvalent metallic solt of these materials are especially preferable for use. The polyvinyl alcohol is accordingly selected for the from among a complete saponified substance, a partial saponified substance, a substance which is nonuniformed per block, a sulfonated polyvinyl alcohol, a graft-copolymerized denatured polyvinyl alcohol, and the like. As the crosslinking agent, a dialdehyde starch is particularly preferable for use. In this manner, an efficient is obtained in addition to the improvement of adhesion and water resistance due to the three-dimensional cure of the alcohol.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a coloring paper for pressure-sensitive copying paper using an organic coloring agent, and in particular, a coloring paper that can obtain a colored image of high density immediately after printing and has good light resistance. This invention relates to colored paper that provides excellent colored images.

``Prior Art'' Pressure-sensitive copying paper uses a color-forming agent microcapsule composition, which is mainly composed of microcapsules containing oil droplets in which an electron-donating organic coloring agent (hereinafter simply referred to as coloring agent) is dissolved, as a support. The upper paper coated on one side, and the other side of the support containing a coloring agent composition containing an electron-accepting coloring agent (hereinafter simply referred to as a coloring agent) as a main component that changes color when it comes into contact with the coloring agent. There is an inner paper coated with a color forming agent microcapsule composition on the opposite side and a lower paper coated with a color forming agent composition on one side of the support. It is used as a copying cent by combining paper, middle paper, and bottom paper in that order. Also, self-coloring pressure-sensitive copying paper, in which a coloring agent and a coloring agent are coated on the same side of a support to enable pressure-sensitive recording on a single sheet, is also well known as a form of pressure-sensitive copying paper.

Coloring agents for such pressure-sensitive copying paper include inorganic coloring agents such as acid clay, activated clay, acpulgite, zeolite, bentonite, silica, aluminum silicate, and phenol-aldehyde polymers and phenol-acetylene polymers. Organic color formers such as phenol polymers, aromatic carboxylic acids, or polyvalent metal salts thereof are known.

Among these, organic coloring agents have a higher coloring ability than inorganic coloring agents, and have the advantage that the color image obtained does not lose its density due to moisture adhesion or normal file storage.

However, even organic coloring agents with such excellent properties have the following drawbacks, and improvement thereof is desired. That is,
Color-forming paper for pressure-sensitive copying using an organic color-forming agent has a low color density immediately after printing, and takes time to reach saturation density (so-called poor initial color development).

(2) The light fastness of the obtained colored image is insufficient, and the color density decreases significantly when exposed to sunlight, ultraviolet rays, fluorescent lamps, etc. for a long period of time.

Methods to overcome these drawbacks include a method of using styrene-butadiene latex as an adhesive constituting the coloring agent composition (Japanese Patent Application Laid-Open No. 196289/1989), and a method of using a water-soluble polymer such as polyvinyl alcohol ( JP-A-55-1581) etc. have been proposed.

However, the current situation is that satisfactory results are not always obtained because these improvements come with new drawbacks such as a decline in water resistance, adhesiveness, and even printability.

``Problems to be Solved by the Invention'' The purpose of the present invention is to improve the above-mentioned drawbacks associated with the use of organic coloring agents, resulting in good initial color development and light fastness, as well as improved printing properties. An object of the present invention is to provide a coloring paper suitable for pressure-sensitive copying paper.

For this reason, the present inventors have conducted extensive research on adhesives constituting coloring agent compositions, and have found that when polyvinyl alcohol is used in a specific proportion and in combination with the crosslinking agent in a specific proportion, 3% of polyvinyl alcohol In addition to the effect of improving adhesive strength and water resistance due to dimensional curing, we discovered that the coloring agent and the coloring agent interacted with each other efficiently, and as a result, the above disadvantages were improved in a well-balanced manner. As a result of these additions, the present invention has been completed.

"Means for Solving the Problems" The present invention provides a coloring paper for pressure-sensitive copying paper containing an organic coloring agent and an adhesive. This is a colored paper for pressure-sensitive copying paper, characterized in that it uses 1% polyvinyl alcohol and also contains a crosslinking agent in an amount of 0.5 to 100% by weight based on the polyvinyl alcohol.

"Function" Examples of the organic coloring agent used in the present invention include Japanese Patent Publication No. 49-10856 and Japanese Patent Publication No. 51-25174.
benzoic acid, p-tert-butyl-benzoic acid, 4-
Methyl-3-nitrobenzoic acid, salicylic acid, 3-phenylsalicylic acid, 3-cyclohexylsalicylic acid, 3-t
ert-butyl-5-methylsalicylic acid, 3,5-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)phenyl)-1-naphthoic acid, etc. Aromatic carboxylic acids and salts of these with polyvalent metals such as zinc, aluminum, magnesium, calcium, cobalt: Japanese Patent Publication No. 40-93
No. 09, Japanese Patent Publication No. 1973-20144, Japanese Patent Publication No. 48-14
Phenol compounds such as 6,6°-methylenebis(4-chloro-m-cresol) as described in No. 409, etc. Phenol-aldehyde resins such as p-phenylphenol-formaldehyde resin, p-tert-butylphenol- Phenolic resins such as phenol-acetylene 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; No. 48-8215, Special Publication 1977
Examples thereof include polymers of aromatic carboxylic acids and aldehydes or acetylene, and polyvalent metal salts thereof, as described in Japanese Patent Publication No. 8216, Japanese Patent Publication No. 52-1326, and the like.

Among these organic coloring agents, 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 metal salts are particularly useful. Preferably used.

The polyvinyl alcohol used as an adhesive component in the colored paper for pressure-sensitive copying paper of the present invention may be a completely saponified product, a partially saponified product, or a polyvinyl alcohol that is block-wise non-uniform (i.e., the intramolecular distribution of residual acetate groups is In addition, copolymerized modified polyvinyl alcohols such as sulfonated polyvinyl alcohol, carboxy-modified polyvinyl alcohol, and graft copolymerized modified polyvinyl alcohols are appropriately selected and used.

Polyvinyl alcohol has a ratio of 5 to 12 to an organic coloring agent.
It should be used in a proportion of 0% by weight, preferably 40% by weight.
It is used in a range of about 90% by weight.

In addition, if the degree of polymerization of polyvinyl alcohol is less than 200, its function as an adhesive will be significantly reduced, and if it exceeds 1800, the fluidity of the coating liquid will deteriorate, and at the same time, the coloring ability of the resulting colored paper will tend to decrease. The degree of polymerization of the polyvinyl alcohol used is 200-1800. It is desirable to select in the range of 400 to 1000.

The colored paper for pressure-sensitive copying paper of the present invention not only uses polyvinyl alcohol as described above as an adhesive component, but also uses a specific amount of its crosslinking agent as an essential component.

Examples of such crosslinking agents include aldehydes such as formalin, glyoxal, dialdehyde starch, and polyacrolein, methylol compounds, epoxy compounds, dicarboxylic acids, etc., which crosslink with parent wood groups in the polyvinyl alcohol component and promote water resistance reactions. Cus B, Al, T represented by their esters, diisocyanate compounds, activated vinyl compounds, and boric acid, borax, etc.
Examples include inorganic compounds such as i, Zr, Srs, Cr, etc.

Among these crosslinking agents, dialdehyde starch is particularly
The printability of the resulting colored paper, especially the adhesive strength required under strong printing pressure as in dry offset printing, and the water-resistant adhesive strength required in wet offset printing are significantly improved, as well as the initial strength required for colored paper. It is the crosslinking agent most preferably used in the present invention because it significantly improves color development and light resistance.

It is not necessarily clear why the use of dialdehyde starch significantly improves the performance of the resulting colored paper as described above. However, the present inventors speculate that the three-dimensional cured film of polyvinyl alcohol and dialdehyde starch protects the organic coloring agent, which has poor light resistance, and that the oil droplets containing the coloring agent and the organic coloring agent As a result, it is presumed that a colored paper with excellent printability, excellent initial color development ability, and excellent light resistance can be obtained.

In addition, in the present invention, the crosslinking agent needs to be used in combination at a ratio of 0.5 to ioomt% with respect to polyvinyl alcohol. If it is less than 0.5% by weight, the desired effect of the present invention cannot be expected, and if it is used in an amount exceeding 100% by weight, the crosslinking agent may remain in the coating solution and cause new problems.

The method for preparing the coating liquid for forming the color former layer is not particularly limited, and may be appropriately prepared according to conventional methods. Adhesives such as starch, casein, gum arabic, carboxymethyl cellulose, styrene-butadiene copolymer latex, vinyl acetate latex, etc. may also be used in the coating liquid, if necessary, within a range that does not impede the effects of the present invention. can. Inorganic pigments such as zinc oxide, magnesium oxide, titanium oxide, aluminum hydroxide, calcium carbonate, magnesium sulfate, and calcium sulfate, as well as various auxiliaries known in the field of producing colored paper, may be added as appropriate.

The coloring agent coating solution prepared by Finished as colored paper for copying paper.

"Examples" Examples and comparative examples are listed below to further clarify the effects of the present invention, but the present invention is not limited to these examples. In addition, parts and % in the examples represent parts by weight and % by weight, respectively, unless otherwise specified.

Example 1 [Preparation of coloring agent coating liquid] 40 parts of a 25% aqueous dispersion of 3,5-di(α-methylbenzyl)zinc salicylate atomized by a sand mill, 70 parts of calcium carbonate, and 10 parts of aluminum hydroxide. ,
10 parts of zinc oxide, 100 parts of a 20% aqueous solution of oxidized modified starch, and 300 parts of water were mixed to obtain a dispersion.

Next, 80 parts of a 10% aqueous solution of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: rPVA-205J) with a degree of saponification of 87 to 89%, a degree of polymerization of 500, and dialdehyde starch (manufactured by Nippon Carlit Co., Ltd., product name) were then added to the obtained dispersion. Name: Kargis 5
A coloring agent coating liquid was prepared by adding 30 parts of a 10% aqueous solution of No.

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

The above coloring agent coating liquid was applied to one side of a 40 g/m base paper with a dry weight of 5 g/n? The mixture was coated and dried to obtain colored paper for pressure-sensitive copying paper.

Example 2 [Preparation of color former coating solution] 60 parts of a 25% aqueous dispersion of p-phenylphenol-formaldehyde polymer, which was atomized using a sand mill.
75 parts of calcium carbonate, 10 parts of zinc oxide, 100 parts of a 20% aqueous solution of oxidized modified starch, and 300 parts of water were mixed to obtain a dispersion.

Next, the resulting dispersion was mixed with 100 parts of a 10% aqueous solution of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: rPVA-1) (7) with a degree of saponification of 98 to 99%, a degree of polymerization of 1000, and dialdehyde starch (Nippon Carlit). A coloring agent coating liquid was prepared by adding 30 parts of a 10% aqueous solution of Calgis No.

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

The above coloring agent coating liquid was applied to one side of a 40 g/m base paper with a dry weight of 7 g/n? The mixture was coated and dried to obtain colored paper for pressure-sensitive copying paper.

Example 3 In Example 1, 2-hydroxy-4-(<4-carboxy-5-hydroxy)phenyl)-1-naphthoate was used instead of zinc 3,5-di(α-methylbenzyl)salicylate as the organic coloring agent. A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that acid was used.

Example 4 In Example 1, dimethylol urea (manufactured by Showa Denko) was used instead of dialdehyde starch as the crosslinking agent.

A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 1, except that RJ-001J (trade name) was used.

Example 5 Example a In Example 1, epichlorohydrin (manufactured by Showa Denko Co., Ltd., trade name rJ) was used instead of dialdehyde starch as a crosslinking agent.
A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that 006J) was used.

Comparative Example 1 A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that 200 parts of a 10% aqueous solution of dialdehyde starch was added.

Comparative Example 2 In Example 1, as polyvinyl alcohol, 10% of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name rPVA-220J) with a degree of saponification of 87 to 89% and a degree of polymerization of 2200 was used.
A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that 50 parts of the % aqueous solution was added.

Comparative Example 3 Example 1 except that 100 parts of a 10% aqueous solution of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: rPVA-202) with a degree of saponification of 87 to 89%, a degree of polymerization of 200 was added as polyvinyl alcohol. A colored paper for pressure-sensitive copying paper was obtained in the same manner as in Example 1.

[Creating the top paper]

A capsule coating liquid prepared by dissolving crystal violet lactone in alkylated naphthalene and microcapsulating this oily liquid was coated on one side of base paper with a dry weight of 48 /
The coating was coated so as to give ri and dried to obtain a top paper.

The following quality evaluation tests were conducted on the eight types of colored paper obtained in this manner, and the results are listed in Table 1.

+1) Printing light fastness test The coated surfaces of the colored paper and the upper paper were placed facing each other, and the colored paper was pressed with a typewriter to develop the color. After the colored paper was left in a dark place for 24 hours, the color density was measured using a Macbeth reflection densitometer, and this was taken as the initial density.

Next, this colored paper was left on an indoor desk, and its color density was measured again after 10 days and 30 days, and the light fastness values after 10 days and 30 days were determined according to the following formula.

(2) Initial color development test The coated surfaces of the colored paper and top paper were placed opposite each other, and color was developed using a falling color tester (weight: 150 g, height: 20 c 1 ml), and 10 seconds after impact using a Macbeth reflection densitometer. The color density was measured.

Next, this colored paper was left in a dark place for 24 hours, and then its color density was measured again. This value was taken as the saturated color density, and the initial color development was evaluated using the following formula.

<3) Using an R1-Dry Picking R1 printing aptitude tester (manufactured by Mei Seisakusho), printing ink of Toughk Value-13 manufactured by Dainippon Ink was printed three times on the coated surface of colored paper, and the powder falling state was evaluated as follows. Sensory evaluation was performed using a three-level evaluation standard.

[Evaluation criteria] 5...1 (excellent)
......(inferior) (4) RI -We
t Picking R1 printing suitability tester (manufactured by Mei Seisakusho) was used, and evaluation was made in the same manner as R1-Dry picking except that printing was performed using dampening water.

"Effect" As is clear from the results in Table 1, the colored paper for pressure-sensitive copying paper obtained in each example of the present invention has excellent initial color development, as well as printing light fastness and surface strength. It was also a good colored paper.

Table 1 Patent applicant: Kanzaki Paper Co., Ltd. Procedures (fushosho) September 2, 1986

Claims (4)

[Claims] (1) In color-forming paper for pressure-sensitive copying paper containing an organic color-forming agent and an adhesive, the adhesive component contains 5% of the organic color-forming agent.
A colored paper for pressure-sensitive copying paper, characterized in that polyvinyl alcohol is used in an amount of 120% by weight, and a crosslinking agent is used in an amount of 0.5 to 100% by weight based on the polyvinyl alcohol. (2) At least the organic coloring agent is selected from aromatic carboxylic acids or polyvalent metal salts thereof, phenolic resins or polyvalent metal salts thereof, polymers of aromatic carboxylic acids and aldehydes or acetylene, or polyvalent metal salts thereof. The colored paper according to claim (1), which is one type. (3) The degree of polymerization of polyvinyl alcohol is 200 to 180
0. The colored paper according to claim (1). (4) The crosslinking agent is dialdehyde starch (
Colored paper described in items 1) to (3).