JPS6228284A - Microcapsule support - Google Patents

Abstract

PURPOSE:To enhance resistance to contamination under pressure, by providing on a support a layer comprising mirocapsules, a composition obtained by polymerizing a water-soluble vinyl monomers in the presence of a high molecular weight latex having a glass transition point of not higher than 60 deg.C, and particulate talc. CONSTITUTION:In the presence of a high molecular weight latex A having a glass transition point of not higher than 60 deg.C, at least one water-soluble vinyl monomer B is polymerized in a solid weight ratio of A:B of 3:97-90:10 to prepare a film-forming composition. Then, an aqueous coating liquid comprising the composition, microcapsules the walls of which are formed of a synthetic resin, and particulate talc as essential constituents is prepared. The coating liquid is applied to a support for a pressure-sensitive recording paper or the like to provide a layer comprising the essential constituents, thereby obtaining the microcapsule support.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a microcapsule support. More specifically, the present invention relates to a microcapsule support having a layer containing microcapsules, a special film-forming composition, and finely powdered talc as essential components.

(Prior art) Microcapsules originated from a microcapsule manufacturing method using a gelatin membrane complex coacervation method developed by NCR over many years for pressure-sensitive copying paper, and subsequently developed for pressure-sensitive copying paper. Recording materials such as paper, pharmaceuticals, fragrances,
BACKGROUND OF THE INVENTION A wide range of vigorous studies have been conducted in the fields of liquid crystal substances, foods, agricultural chemicals, dyes, solvents, rust preventives, health foods, etc., and various products have reached the stage of practical use or practical testing.

In particular, many techniques have already been proposed for microcapsules of hydrophobic substances (oils and/or solids), and among them, the coacervation method (phase separation method) using gelatin membranes has been the main It has been implemented on a commercial scale for pressure copy paper.

Generally, microcapsules are of the pressure-rupture type, and in particular when a liquid is used as the core material, for example, manufacturing, finishing, sorting, etc. of a support coated with a microcapsule-containing coating solution,
The capsules are susceptible to rupture by pressure or frictional forces during printing or normal handling and use. As a result, the microcapsule support may become smudged or its storage life may be reduced. To solve this problem, stilt materials are used as protective or buffering materials for microcapsules. This stilt material is made into a water-based coating solution mixed with microcapsules and generally a water-soluble or water-dispersible binder, which can be applied to paper by various coating methods (e.g., air knife coater, bar coater) or printing method. Generally, a containing layer is formed on a support and dried.

Examples of such stilt materials include glass peas, finely ground cellulose fibers (cellulose flock), ungelatinized starch particles (wheat starch, potato starch, pill flour starch), etc. It is used in an amount of about 10 to 100 parts by weight per 100 parts by weight. These stilt materials generally have a microcapsule-containing layer with inert particles slightly larger than microcapsule particles (generally 10 to 30μ), which provide a buffering effect for the microcapsules and a protection to prevent the microcapsules from being ruptured. It's working.

In addition, microcapsules manufactured by the complex coacervation method using gelatin and anionic polymer electrolytes were often used.0 (Problem to be solved by the invention) The method used has the following problems.

That is, regarding gelatin membrane microcapsules produced by the above method, (1) In principle, it is difficult to obtain microcapsules with a solid content of 20% by weight or more, so productivity per unit volume is low and transportation costs are low. (2) Capsule film material Because it is a natural product, there are large fluctuations in quality and price;
(3) After production, it has a tendency to rot and agglomerate, so it cannot withstand long-term storage.

Several methods have already been proposed as improved techniques to solve such problems, for example, (A) Japanese Patent Application Laid-open No. 5
No. 1-9079, No. 55-84.882, No. 54-5
3679, method for producing microcapsules using urea formaldehyde resin as membrane material, such as 55-158998, (B) JP-A-53-84881, JP-A-54-4998
No. 4, No. 55 47139, No. 56-58536,
There is a method for producing microcapsules using melamine formaldehyde resin as a membrane material, such as No. 56-155636.

Microcapsule slurries of hydrophobic substances using these synthetic resins as membrane materials have a relatively high solids content compared to microcapsule slurries produced by the complex coacervation method. This has been improved in terms of workability and energy saving.

In addition, at least (A
) acrylic acid and/or methacrylic acid, (B)
An aminoaldehyde characterized by using a multi-component copolymer containing as an essential component six or more acrylic heptamers selected from acrylonitrile and/or methacrylonitrile, (C) acrylamide alkyl sulfonic acid and/or sulfoalkyl acrylate. Resin (urea formaldehyde resin, melamine formaldehyde resin,
A method has been proposed for obtaining microcapsules with higher solid content and superior quality by using melamine urea formaldehyde resin as a membrane material (Japanese Patent Application No. 58-136871, same patent application No. 59-160867, patent application No. 59-70959). issue).

According to this method, a microcapsule slurry having an ultra-high solids concentration exceeding 60% from low solids can be obtained in a low viscosity state.

The microcapsule slurry obtained using various synthetic resins, especially aminoaldehyde resin, as a membrane material obtained by such a method is more common than the complex coacervation method microcapsule slurry that has been widely used in the past. In addition to having a high solid content concentration, the microcapsule membrane has excellent density, and is characterized by a low tendency to rot or aggregate during storage.

The ability to obtain a microcapsule slurry liquid of such high concentration brings extremely great benefits, for example, to the production of pressure-sensitive copying recording paper.

In other words, microcapsule technology such as the ceratin membrane complex coacervation method microcapsules cannot obtain a microcapsule slurry with a high solid content, and it is necessary to use a highly concentrated aqueous microcapsule coating solution. It has been impossible to improve the productivity of microcapsule-coated sheets through high-speed coating.

However, there is a strong demand in the industry for improving the coating speed of microcapsule water-based paints as described below.

In other words, if we take pressure-sensitive copying paper as an example, which is the most important application for such microcapsules (one upper paper (C
Paper B) is generally manufactured by using an air knife coater to apply and dry an aqueous solution containing microcapsules of a high boiling point hydrophobic solvent in which triallylmethane phthalide derivatives, fluoran derivatives, etc. are dissolved. On the other hand, the color developer-coated surface (lower CCF paper), which is the opposite surface, is generally coated with a high-concentration, high-viscosity paint with a solids content of 50-70 wt% using a blade coater (flexible blade coater, tray link flake). (coater, floranthene blade coater, etc.), roll coater (kate roll coater, etc.)
, reverse roll coke), gravure coater, and other high-speed coating machines. As is clear from the various bottom positions, the water-based paint used in air knife coaters has a coating viscosity of about 10 to 500 cps and a coating liquid solid content of 20.
A relatively low viscosity and low concentration (low solid content) of about ~45 mm is used, and the coating speed per unit time is also 100~45 mm.
It is said that the limit is about 00 m/h.

In contrast, water-based paints containing color developers generally have a
A high-speed coating method having a solid content concentration of ~65%, a viscosity of 200-5000 cps, and a coating speed of 400-10007 n/mm is generally used. As mentioned above, when manufacturing (coating) pressure-sensitive copying paper, the reality is that there is a significant difference in productivity between the process of applying microcapsule paint and the process of applying color developer paint. , microcapsule paints, and improvements in the productivity of the coating process are highly desired by the industry.

In addition, stilt materials (particles with a larger particle size than microcapsules, such as ungelatinized starch particles, finely pulverized cellulose particles, etc.) used in combination as a pressure buffer material on the surface coated with microcapsule paint are, for example, representative of high-speed coating. In blade coating or gravure coating, which is a conventional method, the blade is scraped off, so there is no buffering material on the coated surface of the coated sheet, and the microcapsule coating layer becomes sensitive to pressure, causing manufacturing and finishing problems. Capsules are easily destroyed due to pressure and frictional force during the printing process and normal handling, and contamination (smudge) is likely to occur.Furthermore, the microcapsules cannot withstand the blade nip pressure during coating, causing partial destruction. There are many things that can be mentioned.

High solid content microcapsule slurry has been developed as a cushioning material even if an unprecedented manufacturing technology for high solid content microcapsule slurry has been established in accordance with recent advances in microcapsule technology that uses synthetic resin as a membrane material. A tilt is necessary. In order to coat the buffer material on the support surface in a form that coexists with microcapsule particles, water is added to the coating solution to make it low in viscosity and concentration, and then the buffer material is coated at a relatively low speed using an air knife coater or bar coater. We are in a situation where we have no choice but to carry out coating.

(Means for Solving the Problems) In view of the current situation, the present inventors have developed a material for protecting microcapsules in a microcapsule-containing layer on a support, and have developed a material that protects microcapsules with a layer containing microcapsules on a support. We conducted extensive research on possible ways to do this. As a result, in the presence of (a) microcapsules whose membrane material is synthetic resin and (b) polymer latex with a glass transition point of 60°C or lower and/or polymer latex with a glass transition point of 60°C or lower (A), at least one water-soluble vinyl polymer CB) is polymerized in the above (A).
), (B) has a solid weight ratio of 6:97 to 90:10, and (C) a microcapsule support having a layer containing finely powdered talc as an essential component. It has been completed.

The microcapsules used in the present invention are manufactured using synthetic resin as a film material, and are obtained by a method called interfacial polymerization method or in-8 intu polymerization method, in which a hydrophobic substance is coated with a synthetic resin film. It is a microcapsule. Specifically, polyamide membrane microcapsules, polyester membrane microcapsules, polyurea membrane microcapsules, epoxy membrane microcapsules, polyureaamide membrane microcapsules, etc. are produced by interfacial polymerization method ζ, or urea formaldehyde resin membrane microcapsules are produced by in-5 in-tu polymerization method. Examples include capsules, melamine-formaldehyde resin membrane microcapsules, melamine-urea-formaldehyde resin membrane microcapsules. Of course, it is also possible to use microcapsules whose membrane material is a composite synthetic resin membrane or double synthetic resin membrane obtained by combining an interfacial polymerization method or an in-3 intu polymerization method with other chemical methods.

Among these microcapsules using synthetic resin as a membrane material, the ones preferably used in the present invention are (1) work stability in producing microcapsule slurry, and (2) microcapsule slurry with relatively high solid content. (4) long-term storage stability of microcapsule slurry; (5) membrane material cost 1- is inexpensive and industrial. In-8j, t
Aminoaldehyde resin membrane microcapsules produced by the u-polymerization method are preferred.

Among these, melamine-formaldehyde resin membrane microcapsules produced by In-3-itu polymerization method are particularly useful due to their excellent membrane density.Furthermore, when using a high solids content microcapsule slurry exceeding 50% by weight, this book Even when mixed with the film-forming composition, which is the other essential component of the invention, it is possible to obtain a coating liquid with a high solid content of much more than 40% by weight, and in the production of copy recording sheets, blade coating method, A microcapsule-coated sheet can be obtained using a high-speed coating method such as a gravure coating method or a roll coating method.

The film-forming composition, which is another essential component of the present invention, is
Polymer latex with a glass transition point of 60°C or less and/or polymeric latex with a glass transition point of 60°C or less (
A composition obtained by polymerizing at least one water-soluble vinyl monomer (B) in the presence of A+, comprising the above (A), (
B) is characterized in that the solid weight ratio is 3:97 to 90:10.

Examples of polymer latexes with a glass transition point of 60°C or lower that can be used as film-forming compositions include various emulsion latexes obtained by emulsion polymerization. diene latenox), MBR (methyl methacrylate-butadiene rubber latex), MSBR (methyl methacrylate-styrene butadiene rubber latex),
Examples include synthetic rubber latex such as CR (chloroprene comb latex) and ■R (imprene rubber latex), and acrylic acid ester emulsion latex.

and at least one water-soluble vinyl monomer (B) in the presence of a polymer latex (A) having a glass transition point of 60°C or lower, and a water-soluble vinyl monomer such as radical polymerization or redonx polymerization. A composition obtained by polymerization using a polymerization method of polymerizing monomers, wherein the solid weight ratio of (A):(B) is 3297 to 90:10. Preferably 5:9
The composition has a ratio of 5 to 80:20.

The temperature is below 60°C, preferably below 408°C.

If the glass transition temperature of the polymer latex exceeds 60°C, the flexibility of the layer containing the microcapsules and the film-forming composition will be lost.

In the polymer latex, 5BR-latex contains styrene-butadiene, MBR latex contains methyl methacrylate and butadiene, MBR latex contains methyl methacrylate, styrene, and butadiene, NBR latex contains acrylonitrile and butadiene, and CR latex contains chlorobrene. DingR latex uses isoprene, polybutadiene latex uses butadiene, vinyl acetate emulsion latex uses vinyl acetate, and vinyl acetate-acrylic emulsion uses vinyl acetate and acrylic esters (methyl, ethyl, butyl, 2-ethylhexyl, etc.). ) Vinyl acetate-ethylene emulsion latex contains acrylic esters (methyl, ethyl, butyl, 2-ethylhexyl, etc.), vinyl chloride latex contains vinyl chloride, vinyl acetate, or ethylene, vinylidene chloride, vinyl chloride, acrylic Acid esters are the main raw materials for each, but in addition to these main raw materials, monomers that can be copolymerized with these main raw materials can also be used to improve the physical properties of the polymer latex. The polymer latex prepared by the above method can also be used as the polymer latex used in the present invention.

That is, monomers that can be copolymerized with the main raw materials of each of the polymer latexes include, for example, ethylenically unsaturated carboxylic acid such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. acid, butadiene,
Conjugated diolefins such as imprene, chloroprene,
Aromatic vinyl compounds such as styrene, methylstyrene, α-methylstyrene, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methacrylic acid-2-
Meccrylic acid esters such as ethylhexyl, acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, ethylene nitrile compounds such as acrylonitrile, methacrylaterile, β-hydroxy acrylate Hydrophilic monomers such as ethyl, β-hydroxyethyl methacrylate, acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-butoxymethylacrylamide, glycidyl acrylate, glycidyl methacrylate, vinyl acetate ,
These include vinyl chloride and vinylidene chloride. These monomers for improving physical properties may be copolymerized with a polymer latex in advance, or in some cases, they may be copolymerized with a water-soluble vinyl monomer in the presence of a polymer latex. May be used together.

The water-soluble vinyl polymers used are vinyl monomers that produce water-soluble polymers through polymerization, such as nonionic vinyl monomers such as acrylamide, methacrylamide, diacetone acrylamide, and vinylpyrrolidone. System monomers, acrylic acid, methacrylic acid, itaconic acid, maleic acid, the polymer latex used to produce this film-forming composition is SBR obtained by a known polymerization method
.

Synthetic rubber latex such as MBR, MSBR, NBR, CR, IR and polybutadiene, emulsion latex such as vinyl acetate emulsion, vinyl acetate-ethylene emulsion, or acrylate emulsion, vinyl chloride latex, vinylidene chloride emulsion glass transition of these polymer latexes Anionic vinyl monomers such as maleic acid half ester, fumaric acid, crotonic acid, dimethylaminoethyl methacrylate, trimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, triethylamine There are cationic vinyl monomers such as ethyl methacrylate, and these include not only one type but also two types.
Can be used in combination with more than one species.

As mentioned above, the composition used in the present invention has a glass transition point of 6
The solid weight ratio of vinyl monomer (B) in the presence of latex (A) at 0°C or lower is (A) + (B) from 6:97 to
It is obtained by polymerizing in a ratio of 100:0. When the ratio of polymer latex to water-soluble vinyl monomer becomes smaller than 3:97, the flexibility of the film formed from the final copolymer composition is lost, and microcapsules are Pressure resistance and friction staining properties are reduced.

The fine powder talc (C) used in the present invention is a white to gray scale-like inorganic powder obtained by finely pulverizing an ore generally called talc, and chemically it is hydrated magnesium silicate (3Mg0.4 It is a material with low hardness (Mohs hardness -1) expressed by S102.H2C).

Talc is industrially available as a powder with various particle size distributions, and in order to obtain the microcapsule support of the present invention, talc has an average particle size of 1 to 10 μm and a particle size distribution of 0.5 μm.
1 to 30μ, preferably 0.2 to 20μ. Talc is generally easily dispersible in water, and generally does not require special pretreatment when preparing an aqueous coating solution, but if necessary, it may be treated in the presence or absence of an anionic or nonionic surfactant. It is also possible to use a mixture mixed and dispersed in water.

The microcapsule support of the present invention includes (a) microcapsules whose film material is a synthetic resin and (
b) Polymerizing at least one water-soluble vinyl monomer (B) in the presence of a polymer latex with a glass transition point of 60°C or lower and/or a polymeric latex CA) with a glass transition point of 60°C or lower. and (c) an aqueous film-forming composition characterized in that the solid ratio of (A):(B) is 3:97 to 90:10, and (c) an aqueous composition containing finely powdered talc as an essential component. A layer containing the above (,), (b) and (c) as essential components is formed by applying a coating liquid onto a support.

That is, in pressure-sensitive recording paper, which is a typical example of a sheet coated with microcapsules, 2 to 70 parts by weight (solid content) of a film-forming composition and fine powder are added per 100 parts by weight (solid content) of microcapsules. Mix 1 to 100 parts by weight of talc, mix other ingredients as necessary, and obtain a solid content of 10 to 70 parts by weight.
Prepare 0 to 70 parts by weight, and apply this coating liquid to air knife caulk.
The solution is coated on a support using a blade coating method to form a layer containing microcapsules, a film-forming composition, and talc as essential components.

Components added to the coating liquid as necessary include various water-soluble polymer substances, water-dispersible polymer substances, thickeners, dispersants, antifoaming agents,
Water-proofing agents, auxiliary stilt materials, etc. that improve the liquid properties, adhesion, water resistance, printability, etc. of the coating solution are used.

Coating with an air knife coater generally has a solid content of 10
This is a method in which an excess amount of a coating liquid with a low solid content and low particle size of about 300 to 30 parts by weight to 50 cps is applied onto a support such as paper, and the excess amount is scraped off with air blown from a nozzle.

Additionally, in the blade coating method, which is a typical example of a high-speed coating method, an excessive amount of a highly concentrated coating liquid with a solid content of 40 to 60% by weight and a viscosity of about 5,000 cps is applied onto the support. The application amount is controlled by scraping off the excess amount with a copper blade, and the coating amount is 500 to 10.
This method coats at a high speed exceeding 0.07 W/mi.

(Functions and Effects) The microcapsule support of the present invention replaces the stilt material, which has conventionally been used as a protective material and buffer material for microcapsules, with a polymer latex having a glass transition point of 60°C or lower and/or a glass transition point of 60°C or less. It is obtained by polymerizing at least one water-soluble vinyl monomer (B) in the presence of a polymer latex (A) having a temperature of 60°C or less;
):(B) is used in place of talc and a film-forming composition having a solid weight ratio of 397 to 90:10.

Therefore, a microcapsule support, such as a microcapsule coated sheet, does not require the presence of a stilt material as a protective material or a buffer material, which was conventionally required to be present in a microcapsule coated layer. Significantly improved friction stability.

Furthermore, by containing finely powdered talc in the microcapsule support of the present invention, (1) it imparts a unique lubricity to the coated surface of the support and prevents undesirable destruction of the microcapsules due to friction or the like; (2) imparts extreme smoothness to the coated surface of the support; (3) silica, alumina, clay, used as a coating for paper or as a printing material;
It has significantly lower hardness than calcium carbonate (Mohs hardness -1), which significantly suppresses wear on coach ink heads and slitters. (4) Appropriate hygroscopicity and oil absorption, making the coated surface easy to write on. (solvent absorption) and printing suitability (ink absorption).

(Examples) Hereinafter, the present invention will be explained in detail using Examples and Comparative Examples.

The evaluation method of the pressure-sensitive copying paper having a coating layer mainly composed of microcapsules of dye precursor solutions obtained in Examples and Comparative Examples is as follows.

(1) The coated surface of pressure-sensitive copying paper CB paper with color development performance and commercially available pressure-sensitive copying paper CF paper (manufactured by Jujo Paper Co., Ltd.) using a phenolic resin color developer.
It was superimposed on a resin (ccp W-50BRJ) and colored by stamping using an electric typewriter (HgRMES-808). The color density after 1 minute and 24 hours after color development was measured using a Hunter colorimeter (manufactured by Toyo Seiki) using an amber filter and expressed as a reflectance value.

The smaller the number, the darker the color is.

(2) Pressure staining property Coated surface of CB paper obtained in the same manner as (1) and commercially available pressure-sensitive paper C
The coated surface of the F paper was overlapped with the coated surface of the CF paper, and a static pressure of 10 kg/i was applied using a Mullen rupture tester on a copper plate and held for 1 minute, and the degree of coloration of the CF surface before and after the test was measured using a Hunter colorimeter (
The reflectance was determined using an amber filter (using an amber filter).

Example-1 2-acrylamido-2-methylpropanesulfonic acid 0
．． A 20% aqueous solution of a terpolymer with a monomer composition of 0.08 mol, acrylic acid 0.58 mol, and acrylonitrile 0.36 mol (viscosity 150 cps at 25'C)
Alkylnaphthalene (Kureha Chemical "KMC-113J") 1 in which 30% by weight of crystal violet lactone and 08% by weight of penduyl leucomethylene blue were dissolved in 79.3 parts of an aqueous solution at pH 4.5 diluted with 30 parts of water (Kureha Chemical Co., Ltd., "KMC-113J").
50 parts were added and emulsified using a homomixer to obtain a Q/W type stable emulsion with an average particle size of 6.5 μm after 10 minutes. Subsequently, 244 parts of a methylated methylolmelamine resin aqueous solution (80% non-volatile content) was added under stirring, and the system was
The mixture was heated to 0° C. and fed for 2 hours, and then cooled to complete microencapsulation.

The microcapsule slurry of this example had a solids content of 65%. In order to remove residual formaldehyde, a small amount of 28 L% aqueous ammonia was added to adjust the pH to 8.0, and the formalin odor completely disappeared.

153.85 parts of the capsules, 40 parts of carboxy-modified styrene-butadiene rubber latex (SBR...glass transition point -5°C1 solid content 50 wt%), and a small amount of dioctyl sulfosuccinate Na salt were dispersed in the presence of In addition, talc with an average particle size of 2.8μ (maximum particle size of 8μ) 50
% aqueous suspension, 60 parts were stirred and mixed to obtain a solid content of 60.3.
H, viscosity 800 cp (B-type viscometer, at 25°C)
A white aqueous coating liquid was obtained.

The aqueous coating liquid was coated with a single-fed blade coater (manufactured by Riki Kumagai).
0 ji/m pressure-sensitive copying paper base paper with a dry coating weight of 3.
Apply to 2g/77L' (coating speed sso
m/m=) was dried to obtain pressure-sensitive copying paper CB paper.

Comparative Example-1 Using the microcapsule slurry of Example-1, a single-fed blade coater (manufactured by Kumagai Riki) was used to coat the microcapsule slurry at 400°C.
50 g/m'' (7) at a speed of m/mi and dried (dry coating amount 3.6.li'/m).
') CB paper for pressure-sensitive copying paper was obtained. Pressure-sensitive copy paper CB of this example
When the capsule-coated surface of the paper was observed under a scanning electron microscope, it was found that there were no flour starch grains as stilt material, all of which had been scraped off by the blade during coating.

In the pressure-sensitive copying paper CB paper of this example, no destruction of microcapsules was observed during coating, but since no stilt material was present, the capsules had a marked tendency to be destroyed in static pressure and friction tests, making it of little practical use. Ta.

Comparative Example-2 Aqueous coating liquid Ill with a solid content of 30% using the microcapsule slurry of Example-1
The mixture was coated and dried on pressure-sensitive copying paper base paper using a Mayer bar coater at a dry coating weight of 4.01/rrj to obtain pressure-sensitive copying paper (C08 paper).

The pressure-sensitive copy paper CB paper of this example has conventionally known standard physical properties.

Example 2 50 parts of ethylene maleic anhydride copolymer (Monsanto; trade name EMA-sl) was dissolved in water under heating to obtain a 10% aqueous solution of ethylene maleic acid copolymer. The aqueous solution 10
0 parts and 250 parts of water were mixed, the pH was adjusted to 4.0 with a 10% NaOH aqueous solution, and 200 parts of the same core material as in Example 1 was emulsified in this using a homomixer to form a stable O/W emulsion. Obtained. To this, 60 parts of a methylated methylolmelamine aqueous solution (Mitsui Toatsu Chemical Co., Ltd., Neelamine T-530J) with a solid content of 50 t was added while stirring, and the mixture was kept at 55°C for 3 hours while stirring to complete microencapsulation. .

The system thickened as the capsule wall formed, but did not lose its fluidity.

The resulting microcapsule slurry had a solids content of approximately 39% and a viscosity of 2400 cps (at 25°C).

2564 parts of the microcapsule slurry, carboxy-modified MSBR with a glass transition point of O'C (methyl mecrylate-styrene-butadiene rubber latex...
20 parts of talc (solid content 50%), 30 parts of talc with an average particle size of 4.9μ (maximum particle size of 20μ), 20 parts of phosphoric acid esterified starch
% aqueous solution and 327 parts of water were stirred and mixed to prepare an aqueous coating liquid with a non-volatile content of 22% and a viscosity of i cps (at 25°C), and coated on base paper for pressure-sensitive copying paper (40 g/m) using an air knife coater. The pressure-sensitive copying paper CB paper was obtained by coating and drying so that the dry coating amount was s, 4y/m''.

Comparative Example-6 2564 parts of the microcapsule slurry of Example-2, 40 parts of cellulose floc [Sanyo Kokusaku Half...KC-Flock+250], 100 parts of a 10% aqueous solution of phosphated starch, and 203.6 parts of water were mixed. Thus, an aqueous coating liquid-■ having a non-volatile content of 25% and a viscosity of 50 cps (at 25°C) was prepared. The aqueous coating liquid was coated on pressure-sensitive copying paper base paper using an air knife coater in the same manner as in Example 2 until the dry coating amount was 4.
81//rrl and dry it to make pressure-sensitive copying paper C.
I got paper B.

Example-6 The same melamine resin membrane microcapsule slurry as prepared in Example-1 was used. Microcapsule Sura I
J-1558 parts, 500 parts of carboxy-modified MBR (methyl methacrylate-butadiene rubber latex, solid content 50%) with a glass transition point of +5°C, average particle size of 3
A water-based coating liquid was obtained by stirring and mixing 600 parts of a 50% dispersion in which 1μ (maximum particle size: 10μ) talc was previously dispersed in the presence of a small amount of anionic polymer surfactant and 462 parts of water. .

The aqueous coating liquid in this example has a solid content of s o wt% and a viscosity of 450.
cps (at 25°C).

The aqueous coating solution was coated and dried on 50 f; l/m high-quality paper using a Krachia coater so that the dry coating amount was 6.5 ji/m to obtain pressure-sensitive copying paper CB paper.

In the pressure-sensitive copying paper of this example, it was confirmed by scanning electron micrographs that there was no destruction of the capsules due to the scraping of the coating liquid by a doctor or the nip pressure during coating.

Example-4 50% by weight of styrene, 30% by weight of methyl methacrylate,
80 parts of MSBR latex with a solid content of 50 chips and pH 7.0 (Tg - 1°C) consisting of 38.5% by weight of butadiene and 1.5% by weight of acrylic acid, 55.9 parts of distilled water,
50 parts of 40% acrylamide aqueous solution, 40% by weight
10 parts of acrylic acid was put into a flask equipped with a cooling tube, a stirrer, and a thermometer, and the following operations were performed while stirring.

First, the flask is heated and the temperature inside the flask is raised to 50C. Next, 7 parts of a 10% by weight ammonium persulfate aqueous solution and 5 parts of a 10% by weight aqueous acidic sodium sulfite solution were added to conduct a polymerization reaction for 1.5 hours, and then a small amount of a 20% by weight aqueous sodium hydroxide solution was added to adjust the pH. 8.0, and a film-forming composition (2) was obtained. Composition - ■ is a milky white viscous water dispersion with a solid content of 40% by weight and a viscosity of 1500 Cps.
(B-type viscometer).

37.5 parts of the film-forming composition-■, 153.8 parts of the microcapsule slurry used in Example-1, 20 parts of finely powdered talc (average particle size 28μ, maximum particle size 8μ), and 137 parts water. A water-based coating liquid was obtained by mixing.

The aqueous coating liquid of this example had a solid content of 60% and a 920 cps (a
It had a viscosity of t25°C).

Using a fountain blade coater (manufactured by Ishikawajima-Harima Heavy Industries), 50.9 parts of the aqueous coating liquid was coated on 70 m' of high-quality paper.
Coating and drying at a high speed of 0 m/mi (dry coating amount: 5.
5,! 9/m ) Pressure-sensitive copying paper CB paper was obtained.

Example-5 720 parts of ethylene vinyl acetate latex (Tg=168C) with solid content of 50% and pH 5.0 consisting of 20% by weight of ethylene and 80% by weight of vinyl acetate, 400 parts of a 20% by weight methacrylamide aqueous solution, 40 parts by weight 100 parts by weight aqueous acrylamide solution, 40 parts by weight acrylic acid 125 parts
1 part and 381 parts of ion-exchanged water were put into a flask equipped with a cooling tube and a stirrer, and the following operations were performed while stirring.

First, the flask is heated to raise the temperature of the liquid inside the flask to 50°C. Next, 3 parts of 10% by weight ammonium persulfate and 2 parts of a 10% by weight aqueous acidic sodium sulfite solution were added to carry out a polymerization reaction for 15 hours. Thereafter, 7 parts of a 20% by weight caustic sorter was added, and the pH was adjusted to obtain a film-forming composition-■.

The composition is a milky white suspension with a solids content of 30% by weight.
It had a particle size of cps.

256.4 parts of the microcapsule slurry, Production Example-2
11.60 parts of the film-forming composition sla IJ-- obtained in advance.
Talc (50 wt% solid content, average particle size 4.4 μm) dispersed in water in the presence of a small amount of dioctyl sulfosuccini-1.Na salt and 1974 parts of water were stirred to obtain a non-volatile content of 25
H, an aqueous coating liquid having a viscosity of 32 cps (25°C) -
(2) was prepared, and was coated on a 40 g/m' base paper for pressure-sensitive copying paper using an air knife coater to give a dry coating weight of 40 g/m' and dried to obtain pressure-sensitive copying paper CB paper.

Example-6 Using the same melamine resin membrane microcapsule slurry as prepared in Example-1, microcapsule slurry I
J-1538 parts, film-forming composition of Production Example-2 1ooo
240 parts of a talc 50% dispersion prepared in the same manner as in Example-2 and 100 parts of a 20% aqueous phosphated starch solution were stirred and mixed to obtain a non-volatile content of 5 Qwt% and 78 parts.
An aqueous coating liquid (■) having a viscosity of 0 cps was obtained.

The aqueous coating liquid was coated with a gravure roll coater at 50 g/rrt.
Pressure-sensitive copying paper CB paper was obtained by coating and drying the mixture on high-quality paper to a dry coating weight of 5.5 mm.

In the pressure-sensitive copying paper of this example, it was confirmed by scanning electron micrograph observation that there was no destruction of the capsules during scraping with a doctor or due to nip pressure.

Example-7 Phenylxylylella 1260 in which 3-diethylamino-6-methyl-7-anilinofluorane is dissolved in a five-fold chain
and 978 parts of terefuculoyl chloride dissolved in 30 parts of phenylxylylethane were mixed, and polyhinyl alcohol (manufactured by Kuraray Co., Ltd., Popal-205) was mixed.
200 of a 2wt aqueous solution was added and emulsified with a homomixer to obtain an O/W emulsion with an average particle size of 4μ.

Then, while cooling and stirring, 5.58 parts of diethylene l-IJ amine and 288 parts of sodium carbonate dissolved in 60 parts of water were gradually added dropwise, followed by stirring at room temperature for 24 hours to form a mixture of diethylene triamine and terephthaloyl chloride. A polyamide membrane microcapsule slurry (for black coloring) was obtained by interfacial polycondensation.

The microcapsule slurry of this example has a solid content of 605 wt%.
, and had a viscosity of 220 cps (25°C).

Said Capsule Slur IJ-32.8 parts, the same film-forming composition used in Example-4 - 12.5 parts, styrene-butadiene-latenox (solid content 50%) 0.6 parts, talc (particle size 5 4 parts of .8μ) and 111 parts of water were stirred and mixed to obtain an aqueous coating liquid-■ (solid content: 30 g, 65 cps).

Apply the water-based coating liquid of this example to 70g1rr using a Mayer bar coater.
A pressure-sensitive copying paper CB paper was obtained by coating and drying the mixture on 1 liter of high-quality paper at a dry coating weight of 4.8 g/m'.

Example-8 8 parts of the melamine resin membrane microcapsule slurry IJ-15 obtained in Example-1, 137.5 parts of the same film-forming composition used in Example-4, and 10 parts of talc with an average particle size of 8 μm. , 25 parts of wheat starch granules with an average particle size of 20μ, and 215 parts of water.
．． Three parts were stirred and mixed to obtain an aqueous coating liquid. (Solid content 30%
, viscosity 13 cps) The aqueous coating liquid was dried and applied to a base paper for pressure-sensitive copying paper of 501/rrl using an air knife coater with a dry coating weight of 4.
The mixture was coated and dried to obtain a pressure-sensitive copying paper 08.

Comparative Example-4 32.8 parts of the polyamide membrane microcapsule slurry obtained in Example-7, 3 parts of styrene-butadiene latex (solid content 50%), and 2.55 parts of water were stirred and mixed to prepare an aqueous coating liquid-■ I got it.

The aqueous coating liquid was added to 7 parts g/rr as in Example-7. Pressure-sensitive copying paper 08 was obtained by coating and drying the mixture on a base paper in a dry coating amount of 4.89 parts m. The pressure-sensitive copying paper of this example had a tendency to develop color even under slight pressure, and was not practical.

Comparative Example-5 Using the same melamine resin membrane microcapsule slurry as prepared in Example-1, microcapsule slurry I
J-1538 parts, 30 flour starch granules with an average particle size of 18μ
0 parts, 1000 parts of 10% PVA aqueous solution and 16 parts of water
Two parts were mixed to obtain an aqueous coating liquid -■.

The aqueous coating liquid of this example had a nonvolatile content of 46.7% and a viscosity of 800 cps (25°C). In the same manner as in Example 3, it was coated on high-quality paper using a gravure roll coater and dried to give a pressure-sensitive copying paper of 0.
I got 8 papers.

When the coated surface of the pressure-sensitive copying paper of this example was observed with a scanning electron microscope, no wheat starch grains were present as a stilt material, and partial destruction of the microcapsules was observed. This is probably because the starch particles were scraped off by the doctor and the capsule was partially destroyed by the nip pressure with the bank up roll.

Next, regarding the pressure-sensitive copying papers obtained from Examples 1 to 8 and Comparative Examples 1 to 5, color development performance, pressure stain resistance, friction stain resistance,
Table 1 summarizes the results of testing the degree of capsule destruction.

The present invention has been explained above using Examples and Comparative Examples.
As is clear from 1, the microcapsule support of the present invention, typified by pressure-sensitive copying paper, has excellent pressure stain resistance and abrasion resistance without using a stilt material, which was conventionally considered essential. Possesses contaminating properties.

Claims (1)

[Claims] 1) On a support, (a) microcapsules made of synthetic resin as a membrane material, (b) polymer latex with a glass transition point of 60°C or less and/or polymeric latex (A) with a glass transition point of 60°C or less. ), at least one water-soluble vinyl monomer (B) is polymerized in the presence of (A)
: A film-forming composition characterized in that (B) has a solid weight ratio of 3:97 to 90:10, and (C) a microcapsule support having a layer containing finely powdered talc as an essential component.