JPH02102095A - Sheet coated with microcapsule - Google Patents

Abstract

PURPOSE:To increase the stability of an application liquid by adding latex containing unsaturated amide carboxylate of a vinyl group to the liquid to be applied. CONSTITUTION:In a sheet coated with a microcapsule consisting of a microcapsule containing an amide and/or an amine compound applied on a support, latex containing unsaturated amidecarboxylate of a vinyl group is added to the liquid to be applied. The amide and/or amine compounds are such compounds shown by formulae I to IV. The alkyl group shown by R1 to R12 involves a saturated and an unsaturated substituted or unsubstituted alkyl group, and can be either one of a linear alkyl group, a branched alkyl group and a cycloalkyl group. These alkyl groups are preferably those with 1 to 20 carbons excepting the carbon atom of the substituted group. In addition, the aryl group expressed by R1 to R12 involves both unsubstituted and substituted aryl groups and is preferably that with 6 to 14 carbons excepting the carbon atom of the substituted group. These are represented by the phenyl group, naphthyl group and anthryl group.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to a sheet coated with microcapsules, and particularly to an improvement of a sheet coated with microcapsules containing an amide and/or amine compound.

“Prior Art” Amide and/or amine compounds are used in combination with ligand compounds and iron (
III) In recording sheets and the like that utilize a color reaction caused by complex formation of compounds, they have recently attracted much attention because they have properties that improve instant color development and stability over time.

Microcapsules usually have a particle size of several micrometers to several tens of micrometers, and are made by covering the internal phase of pharmaceuticals, pesticides, fragrances, dyes, liquid crystals, temperature-indicating materials, adhesives, etc. with a natural or synthetic polymer film. It has great advantages such as chemically or physically protecting internal substances and being able to handle liquids as solids, and is used in a wide range of fields including pressure-sensitive copying paper.

As a method for producing microcapsules, the coacervation method (for example, U.S. Pat. No. 2,800,457, U.S. Pat.
1n - Many techniques have been developed, such as the in-situ polymerization method (for example, the method shown in Japanese Patent Publication No. 36-9168, Japanese Patent Application Publication No. 51-9079, Japanese Patent Application Publication No. 53-84881, etc.).

The microcapsules produced in this way are mainly coated on a support such as paper, synthetic paper, or film, and used as a microcapsule-coated sheet.

In this case, various binders are required to adhere the microcapsules to the support, and the use of latex is particularly preferred from the viewpoint of adhesive strength.

However, when ordinary latex is used as a binder for a coating solution for microcapsules containing the above-mentioned amide and/or amine compound, the coating solution tends to lose stability over time, resulting in thickening, aggregation, and even Since defects such as poor adhesion to the support occur, improvements are desired.

"Problems to be Solved by the Invention" As a result of intensive research into improving these defects, the present inventors found that when latex made of specific components is used,
The inventors have completed the present invention by discovering that the stability of a capsule coating solution containing an amide or amine compound can be efficiently improved, and the adhesion to a support is also extremely good.

"Means for Solving the Problems" The present invention provides a microcapsule-coated sheet in which microcapsules containing an amide and/or amine compound are coated on a support, and a latex having a vinyl unsaturated carboxylic acid amide in the coating liquid. This is a microcapsule-coated sheet characterized by containing.

"Function" Examples of the amide and/or amine compounds preferably used in the present invention include compounds represented by the following general formulas (1) to (IV).

(In the formula, R1""RI2 is H, an alkyl group, or an aryl group, respectively, and R+ +Rz moR3, R
4+R5+Rh, R7+Ra +Rq, R+o+R
z+R, □ indicates 4 or more carbon atoms. ) The alkyl group represented by R, -R, □ includes saturated and unsaturated substituted and unsubstituted alkyl groups, and may be any of a straight-chain alkyl group, a branched alkyl group, and a cycloalkyl group. These alkyl groups preferably have 1 to 20 carbon atoms, excluding carbon atoms in the substituent portion. Further, the aryl group represented by R1 to R+z includes both unsubstituted and substituted aryl groups, and preferably has 6 to 14 carbon atoms excluding the carbon atoms in the substituent part, and specific examples thereof include , phenyl group, naphthyl group, anthryl group, etc.

To form microcapsules, the above-mentioned amide and/or amine compound can be used alone as a core material, but it can also be used in combination with other hydrophobic media.

As the hydrophobic medium, those generally known in the field of microcapsules can be used as appropriate, such as vegetable oils such as cottonseed oil, kerosene, paraffin, naphthi/oil, mineral oils such as chlorinated paraffin, and alkylated biphenyls. , aromatic hydrocarbons such as alkylated terphenyl, alkylated naphthalene, diarylethane, triarylmethane, and diphenylalkane; alcohols such as oleyl alcohol, tridecyl alcohol, benzyl alcohol, ■-phenylethyl alcohol, and glycerin; Organic acids such as oleic acid, dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, dioctyl phthalate,
Esters such as diethyl adipate, propyl adipate, di-n-butyl adipate, dioctyl adipate, organic phosphorus compounds such as tricresyl phosphate, tributyl phosphate, tributyl phosphite, tributylphosphine oxide, phenyl cellosolve, penzyl Ethers such as carbitol, polypropylene glycol, propylene glycol monophenyl ether,
Examples include ketones such as diisobutyl ketone and methylhexyl ketone, and alkylene carbonates such as ethylene carbonate and propylene carbonate.

As the microencapsulation method applied to the present invention, conventionally known coacervation method, interfacial polymerization method, 1ns
Examples include the itu method, among others, Japanese Patent Application Laid-Open No. 53-848
Preferably, the wall is made of a melamine formaldehyde resin as described in No. 81.

The microcapsule-coated sheet of the present invention uses a latex containing a vinyl-based unsaturated carboxylic acid amide as an adhesive in a coating solution containing microcapsules containing an amide and/or amine compound as described above. .

Examples of the vinyl unsaturated carboxylic acid amide include acrylamide, methacrylamide, N-methylol acrylamide, diacetoacrylamide, and the like. These monomers account for 0.1 to 20% by weight of the total monomers.
, more preferably in a range of 0.5 to 10% by weight.

Furthermore, aliphatic conjugated diolefin monomers, aromatic vinyl monomers, vinyl unsaturated nitrile monomers, vinyl unsaturated acid monomers, and other olefin monomers may be selected and used as appropriate. and constitute the latex of the present invention.

First, examples of aliphatic conjugated diolefin monomers include 1,3-butadiene, 2-methyl-1°3-butadiene, 2,3-dimethyl-1,3-butadiene, and halogen-substituted butadiene. These monomers are used in an amount of 0 to 75% by weight based on the total monomers.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, vinyltoluene, monochlorostyrene, etc., and these monomers are used in an amount of 0 to 75% by weight based on the total monomers.

Examples of vinyl unsaturated nitrile monomers include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, etc., but these monomers account for 0% of the total monomers.
It is used in a range of about 20,000% by weight.

Vinyl unsaturated acid monomers include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, itaconic acid, fumaric acid,
Unsaturated carboxylic acids such as maleic acid and maleic anhydride; monoalkyl esters of unsaturated dicarboxylic acids such as monoethyl itaconate, monobutyl fumarate, and monobutyl maleate; sulfonityl sodium acrylate, methacryl Examples include unsaturated sulfonic acids such as acid sulfoprobil sodium salt and acrylamide propane sulfonic acid, and their alkali salts.
These monomers are used in an amount of about 0 to 10% by weight based on the total monomers.

Other olefinic monomers include, for example, alkyl esters of acrylic acid and methacrylic acid such as methyl acrylate, methyl methacrylate, ethyl acrylate, and butyl acrylate; halogen-substituted ethylenes such as vinyl chloride and vinylidene chloride. These monomers are used in an amount of 0 to 20% by weight based on the total monomers.

A more preferable latex for use in the present invention is a system in which vinyl unsaturated carboxylic acid amide is used in combination with styrene and butadiene as hydrophobic monomers, and a coated paper with high surface strength can be obtained. Furthermore, a system in which a vinyl unsaturated acid monomer is used in combination as a hydrophilic monomer is also preferable from the viewpoint of latex stability.

The method for producing the specific latex used in the present invention is not particularly limited, but it may be produced by a conventional emulsion polymerization method or the like.

In the present invention, if necessary, a white pigment, a water-soluble adhesive, a dispersant, a fluorescent whitening agent, a color dye, UV absorbers, ligand compounds, organic bases, desensitizing ingredients, capsule protectants, antipackaging agents, preservatives,
An acid etc. can be added as appropriate.

Examples of white pigments include oxides, hydroxides, carbonates, sulfates, halogen compounds, acid clay, activated clay, etc. of aluminum, zinc, magnesium, calcium, titanium, etc.
Clays such as attapulgite, zeolite, bentonite, kaolin, calcined kaolin, and even JP-A-55-1
Examples include surface-treated calcium carbonate as described in Japanese Patent No. 03994.

Examples of water-soluble adhesives include gelatin, albumin,
Proteins such as casein, starches such as grain starch, pregelatinized starch, oxidized starch, etherified starch, and esterified starch, celluloses such as carboxymethyl cellulose and hydroxyethyl cellulose, and polysaccharides such as agar, sodium alginate, and gum arabic. Examples include water-soluble natural polymer compounds, water-soluble synthetic polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, maleic acid copolymers, and the like.

The coating solution containing microcapsules containing an amide and/or amine compound in the present invention can be prepared using various known machines such as an air knife coater, a roll coater, a size press coater, a curtain coater, a bill blade coater, and a short dwell coke. It is applied onto a suitable substrate such as paper, synthetic paper, synthetic film, etc. by a coating method or a printing method.

"Example" In order to make the effects of the present invention even clearer, the case where pressure-sensitive copying paper is obtained will be described as an example. However, these are examples of the present invention, and it goes without saying that the present invention is not limited thereto. In addition, unless otherwise specified, "part" and "%" in the examples respectively refer to "part" and "%".
Parts by weight J and "% by weight" are shown.

Example 1 (Preparation of top paper) 20 parts of stearyl gallate was mixed with 7 parts of di-n-butyl adipate.
An internal phase oil was obtained by heating and dissolving in a mixed solution of 0 parts of dibenzylamine and 10 parts of dibenzylamine. Ethylene-maleic anhydride copolymer (
A 20% aqueous solution of caustic soda was added to 200 parts of a 3% aqueous solution of EMA-31 (trade name, manufactured by Monsanto) to adjust the pH to 4.
．． 8. Emulsify this internal phase oil in the strained liquid and reduce the average particle size to 15μ.
m, the system was heated to 75°C. Subsequently, 80 parts of a 50% melamine formaldehyde initial condensate aqueous solution (trade name: Cymel 350, manufactured by Mitsui Toatsu Chemical Co., Ltd.) was added to this system and further emulsified at 75°C to give an average particle size of 9 μm. While stirring at 75°C, 0.1N sulfuric acid was added dropwise over 2 hours to bring the pH to 3.8, and then heated to 90°C.
The mixture was heated to C and further maintained at that temperature for 4 hours to obtain a milky white capsule dispersion.

Next, 50 parts of wheat starch powder and 3 parts of pulp powder were added to this dispersion.
0 parts, 40 parts (solid content) of a copolymer latex consisting of 40 parts of 1,3-butadiene, 55 parts of styrene, and 5 parts of acrylamide as a binder were added and mixed, and water was added so that the solid content concentration was 23%. A capsule coating liquid was obtained. The obtained coating liquid was applied to 40 g/board of base paper with a dry weight of 6 g/rd.
The upper paper was obtained by coating with an air knife coater so that the following results were obtained.

(Preparation of the bottom sheet) To 800 parts of 5% aqueous caustic soda solution, 89 parts of 4-tertbutylbenzoic acid, 125 parts of diphenyl phosphate ester,
To an aqueous solution prepared by adding 70 parts of sodium laurylbenzenesulfonate, an aqueous solution of 108 parts of ferric chloride dissolved in 500 parts of water was added under strong stirring to form a pale yellow fine particulate ternary double salt. After that, a slurry was obtained by processing with a sand grinder.

Next, 1 part of sodium polyacrylate and 1 part of hydroxyethyl cellulose were dissolved in 200 parts of water, and the above slurry was added to this by 20 parts of solid content, 20 parts of aluminum hydroxide, 10 parts of titanium oxide, 50 parts of light calcium carbonate, After adding 5 parts of p-toluenesulfonic acid and stirring and dispersing it vigorously,
A coating liquid was obtained by adding 15 parts of carboxy-modified styrene-butadiene copolymer latex (solid content concentration 50%).

Apply the obtained coating liquid to 40 g/rrf neutral paper (paper surface p) (6
, 5) was coated with a rod blade coater and dried to give a dry weight of 6 g/rd to obtain a lower paper.

Comparative Example 1 Top paper was prepared in the same manner as in Example 1, except that 40 parts (solid content) of a copolymer latex consisting of 40 parts of 1,3-butadiene, 55 parts of styrene, and 5 parts of acrylic acid was used as the binder for the top paper. I got the bottom paper.

Example 2 Example 1 except that 40 parts (solid content) of a copolymer latex consisting of 40 parts of 1,3-butadiene, 55 parts of styrene, 4 parts of acrylamide, and 1 part of acrylic acid was used as the binder for the upper paper. Upper paper and lower paper were obtained in the same manner as above.

Example 3 As the internal phase oil, 25 parts of stearyl gallate was added to N.

A capsule coating liquid was obtained in the same manner as in Example 1, except that a solution heated and dissolved in 75 parts of N-di-n-butylacetamide was used. After measuring the viscosity of the obtained coating liquid immediately after preparation and after standing for 24 hours, this coating liquid was applied to a 40 g/rrr base paper using an air knife caulk so that the dry weight was 6 g/rrr. I got the top paper. The lower paper was obtained in the same manner as in Example 1.

Comparative Example 2 Copolymer latex 4 consisting of 40 parts of 1,3-butadiene, 55 parts of styrene, and 5 parts of acrylic acid as a binder
An upper paper and a lower paper were obtained in the same manner as in Example 3 except that 0 part (solid content) was used.

The following evaluation tests were conducted on the five types of top paper and bottom paper thus obtained, and the results are listed in Table 1.

"Evaluation Test" (1) Colored Image The upper paper and the lower paper were combined and printed using a typewriter, and the image copied on the lower paper was visually judged.

(Evaluation criteria) ○: Good.

x: Uneven color development occurred.

(2) Scratch stains The top paper and the bottom paper were rubbed together, and the scratch stains on the bottom paper were visually determined.

(Evaluation criteria) ○: Slight and good level.

×: Considerable staining occurred.

(3) Condition of coating liquid The state of the coating liquid at the time of preparation was visually judged.

(Evaluation criteria) ○:? cE clusters are not produced at all.

×: Aggregation occurs.

(4) Viscosity Regarding the coating liquids of Example 3 and Comparative Example 2, the viscosity immediately after preparation (
The viscosity (20"C) after standing for 24 hours was measured using a B-type viscometer, and the values are shown.

〔effect〕

As is clear from the examples, the microcapsule-coated sheets obtained in the present invention were excellent, with no aggregation or thickening of the coating solution.

Table 1

Claims (3)

[Claims] (1) A microcapsule-coated sheet in which microcapsules containing an amide and/or amine compound are coated on a support, characterized in that the coating liquid contains a latex having a vinyl-unsaturated carboxylic acid amide. Capsule application sheet. (2) The microcapsule-coated sheet according to claim (1), wherein the latex contains a vinyl unsaturated acid monomer as a constituent component. (3) The microcapsule-coated sheet according to claim (1), wherein the latex contains styrene and butadiene as constituent components.