KR820000023B1 - Recording sheet - Google Patents

Abstract

A pressure - sensitive copying material with microencapsulated dyes for offset printing produced images with a min. amt. of stain or fog. The material was formed by coating a support sheet or foil with a dispersion contg. hydrophilic-colloidal-walled microcapsules of hydrophilic dye, a hardener for the hydrophilic colloid, and an aq. alkali salt soln. of a copolymer of >=1 olefinic monocarboxylic acid and 1 monomer of an acrylic or methacrylic polymer.

Description

Record sheet

The present invention relates to a capsule coating record that improves color and background fouling, especially when printing on a recording sheet coated with a microcapsule coating liquid containing fine particles of a hydrophobic substance containing an electron-donating organic coloring agent. It is about a sheet.

Regarding the preparation method of microcapsules containing fine particles of a conventional hydrophobic substance, core cell basis methods such as those described in the specifications of US Pat. Nos. 2800457 and 2800458 are well known.

Core cell bastion is a general term for a phenomenon in which organic matters and colloids of opposite salts are added to an aqueous solution of a hydrophilic colloidal material, and are separated from each other. For example, the aforementioned US Patent No. 2800457 describes the preparation of capsules as follows. The process is described.

(1) A step of emulsifying an oily substance in an aqueous solution of an ionizable hydrophilic colloidal substance. … Emulsification Process

(2) After mixing an aqueous solution of a hydrophilic colloid material which can be ionized and has a reverse charge with the above-mentioned hydrophilic colloid material to the emulsion of (1), the core cell bastion is caused by pH adjustment, dilution or the like. The process of obtaining the core selbait adhered to the circumference of the remains. … Core cell basis process

(3) A step of cooling and coreling the core selvaate. … Gale Process

(4) Process of hardening corecellate by pH adjustment and addition of hardening | curing agent. … Hardening process

In addition, for example, in the case of preparing a microcapsule coating liquid for pressure-sensitive copy paper, the following fifth process is applied.

(5) Finishing process … Fluorescent dyes, organic pigments, methyls for the purpose of adding preparations such as pulp powder, casein, starch, hydroxyl group ethyl cellulose, etc., to add coating color tones, and to improve whiteness in order to have a coating property. It is included in the process of adding dye, such as a biot, etc.

In addition, disinfectants, preservatives, and preservatives are added before and after the paint composition is completed for long-term preservation of the capsule coating solution.

Examples thereof include sorbic acid, sorbic acid pentachloride, pentachlorophenol, chloramine T, salts of methylnaphthoquinone, paraoxy benzoate, formaldehyde, glutaraldehyde and the like.

In addition, preservation of the coating solution before and after the completion of the coating composition to 20 ℃ or less for the same purpose brings a good effect.

When the microcapsules obtained as described above are applied to well-known pressure-sensitive copy paper using a color reaction of an electron-donating organic colorant and an electron-accepting colorant, for example, printing a ruled line, a fingerprint, or the like. The following drawbacks are identified and improvement is desired.

In other words, in recent years, a business form printing of a pressure-sensitive copy paper has been widely adopted as a roll offset printing, in particular a wet offset printing. However, as a printing method, a microcapsule containing an electron-donating organic coloring agent on one side of the same sheet is used. When the coating liquid is applied and the so-called heavy paper (middle paper) coated with the coating liquid containing an electrolytic coloring agent on the other side is printed, the capsule is destroyed by the pressure and the oil in the capsule And since the coloring agent transfers, color staining generate | occur | produces on the whole surface of the coloring agent application surface of the wound heavy paper.

In the case of wet offset printing of the microcapsule coated surface, proteins, surfactants, adhesives, and other preparations in the coated layer affect the blanket surface and the plate surface. There is a flaw.

The pressure resistance of the capsule is also improved by adding an adhesive such as polyvinyl alcohol, casein, starch, sodium alkoxide carboxymethyl cellulose, hydroxyl methyl cellulose, or hydroxyl ethyl cellulose in the capsule dispersion after curing. The purpose of prevention of color staining and background staining in printing does not bring any intrinsic improvement.

It is a main object of the present invention to provide an improved capsule coating recording sheet of color and background stains in printing.

Other objects and advantages of the present invention will become apparent from the following description.

The present invention relates to a dispersion of microcapsules containing microparticles of hydrophobic substances and retaining a hydrophilic colloidal substance as a wall membrane material, which comprises (a) a curing agent and (b) at least one olefinmonocarboxylic acid. A recording sheet formed by applying a coating liquid containing an alkali salt of a copolymer onto a surface of a supporting gas.

Preferably, the alkaline salt of the water-soluble polycopolymer has a surface strength of 40 dyne / cm or more in a 1% by weight aqueous solution, and more preferably, the above-mentioned polycopolymer is at least one olefin monocarboxylic acid and one kind. It is a copolymer with the acryl-methacrylic-type monomer mentioned above.

The microcapsules of the present invention are, for example, US Pat. Nos. 2,800,457, 2,800,458, Re24899, No. 38-1882, No. 38-2981, No. 48-43547, No. 50-140376. It is prepared by the ordinary core cell basis described in Japanese Patent Application Laid-Open No. 51-118509, Japanese Patent Application No. 52-9022, and the like.

Hydrophilic colloidal materials commonly used in the core cell basis method include natural and synthetic materials such as gelatin, casein, gum arabic, sodium alginate, carboxymethyl cellulose, polyvinyl alcohol, methyl vinyl ether, and maleic anhydride copolymer. It is well known, and in the present invention, since such natural and synthetic hydrophilic colloidal substances are appropriately selected and used, it is more preferable to use at least gelatin because the most stable capsule is obtained.

Hydrophobic substances embedded in capsules include various mineral oils such as natural mineral oil, animal oil, vegetable oil and synthetic oil, and include, for example, petroleum, kerosene, paraffin oil, fish oil, soybean oil, castor oil, linseed oil, and alkyldi. Phenyl biphenyl derivatives, naphthalin derivatives, alkylbenzene derivatives, high ester derivatives, aliphatic carboxylic acid esters such as phenolic ethanol, benzyl alcohol, azifinic acid esters, aromatic carboxylic acid esters such as futalate esters, tributyl phosphate, etc. This is illustrated.

In the case of the capsules used for the pressure-sensitive copying paper, these emulsions include one or more kinds of electron donor organic colorants such as crystal biorelagutone, maracaido green inlagutone, benzoyl icomethylene blue, roodamine B-lactam, and furuoran, If necessary, light resistance modifiers such as benzotriazole and the like are dissolved and incorporated in the capsule.

Pressure-sensitive copy paper is a type in which the aforementioned capsule and the electron-accepting colorant are coated on the other side of the sheet, and a single color paper is formed by applying the capsule and the electron-soluble colorant to the same side of the sheet. Examples of the electron-accepting colorants for use include organic acid such as activated clay, acidic clay, azabalite, silica and aluminum silicate, phenolic compounds, phenolic polymers, aromatic carboxylic acids and polyvalent metal salts thereof. Substances and the like are known. (E.g., Special Public Office 49-10856, Special Public Office 51-25174, etc.)

In the present invention, a core selbate film of hydrophilic colloidal material is formed around the fine particles of hydrophobic material, and the curing agent and an alkali salt of a specific copolymer are added after cooling and galling the core selbait film. The alkali salts of the and copolymers may be added to the capsule dispersion at the same time, or may be added to one side before the other is added.

In any case, it is necessary to include the alkali salts of the curing agent and the copolymer in the dispersion of the cooled and galled capsules, and in addition to the operation of adding the alkali salts of the copolymer in a state where the curing agent is still free in the conventional curing treatment. It is one of the effective methods in this invention.

By the way, the curing agent effective in the present invention is, for example, formaldehyde, copper oxysal, glutaraldehyde-free nogocrolic acid, glycerin-aldehyde, saxynaldehyde, acrolein, dialdehyde starch, 2-methylglutalaldehyde, glotonaldehyde, diglin Aldehydes such as aldehydes, citroneral, cinnamic aldehydes, urea formaldehyde resins, triazine formaldehyde resins, polyamide formaldehyde resins, benzinone, microhexane-1.2-zion, cyclobentan-1.2-zion, diacezyl Diketones, such as 2.3-bentanzion, 2.5-hexane zion, and 2.5-hexene zion, ethylene glycol dicytriethyl ether, polyethylene glycol glycidyl ether, polyamide epichlorohydrin resin, triglyceric isocyanurate Epoxy gide, 7.8- diphenyl biscyclo (2.2.2) -7- oakdene -2.3.5.6-detracarboxyl group ligguian hydrite, telephthaloyl chromium For example, acid anhydrides, acid chlorides, etc., such as 4, 4'- diphenylmethane disulfonyl chloride, are mentioned.

In the present invention, at least one of such curing agents is appropriately selected and used, and aldehydes are more preferably used in view of the safety of the dispersion of the capsule. The amount of the curing agent is not necessarily limited, but is usually controlled in the range of 1 to 50 parts by weight, more preferably 3 to 30 parts by weight, based on 100 parts by weight of the hydrophilic colloidal material.

The alkali salt of the specific copolymer used in the present invention is an alkali salt of a copolymer obtained by copolymerizing at least one or more olefin monocarboxylic acids and at least one monomer copolymerizable with the same.

Here, olefin monocarboxylic acid is monocarboxylic acid which has one double bond, For example, acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, vinyl acetic acid, aryl acetic acid, biroterepic acid, (beta)-benzoyl acrylic acid Examples thereof include acrylic acid, methacrylic acid and crotonic acid.

Moreover, as a monomer copolymerizable with said olefin monocarboxylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, iSO-butyl acrylate, t-butyl acrylate, oak t-acrylate, 2- Ethylhexyl acrylate, decyl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, iSO-butyl methacrylate, t-butyl methacrylate, Alkyl esters to dialkyl esters of olefincarboxylic acids having an alkyl group having 18 or less carbon atoms such as dibutyl methylate; Acrylamide; Methacrylamide; N-methylol acrylamide; N-methylol methacrylamide;

For example, Cellsolve acrylate to methacrylate, such as ethyl cellsolve acrylate, a butyl cell solve acrylate, an ethyl cell solve methacrylate, a butyl cell solve methacrylate;

Acrylonitrile, methacrylonitrile, polyethylene glycol acrylate, polyethylene glycol methacrylate, glycidyl acrylate, glycidyl methacrylate, β-hydroxyl group propyl acrylate, β-hydroxyl group methacrylate alkyl vinyl ethers having 18 or less carbon atoms or alkyl propenyl ethers such as n-butyl vinyl ether, 2-ethylhexyl vinyl ether, n-butyl propenyl ether and the like;

Hydrophobic and hydrophilic monomers such as vinyl phenyl ketone, alkyl vinyl ketone, vinyl chloride, vinylidene chloride, vinyl acetate, butachen, chloroprene, isoprene, vinyl birrolidone, and acrolein, but among these, alkyl groups having 18 or less carbon atoms Alkyl acrylates to alkyl methacrylates, acrylonitrile, methacrylonitrile, acrylamide and methacrylamide having excellent retention of oil in the capsules, especially the capsules, have a high pressure when printing a roll offset. It is used more suitably as it is effective in preventing the full color staining caused by the breakdown of the capsule.

In the copolymer used in the present invention, sufficient water solubility is not obtained when the content of the olefin monocarboxylic acid is less than 8 mol (mole)%, and when the content is more than 90 mol%, there is a possibility that the moisture absorption resolubility of the copolymer may be increased. It is preferable that the mole ratio of olefin monocarboxylic acid occupies 8-90 mol% of a copolymer.

In the copolymer of the present invention, the above-mentioned olefin monotonic acid and the monomer copolymerizable with the above-mentioned persulfate in water or methanol, ethanol, isopropenol, butanol, ethyl acetate, methyl ethyl ketone, toluene, xylene or the like or a mixed solvent Polymerization initiators such as girly, anmony persulfate, hydrogen peroxide, gumenhydroxypaoxide, iron (II), chromium ion, sulfite, hydroxyl groupamine, hydrazine, benzoylpaoxide, asobisisophthylnitrile, secondary alcohol, mel It is copolymerized as a well-known method using various polymerization adjuvant, such as polymerization regulators, such as a captohobic acid, and an emulsifier, such as a sodium lauryl sulfate.

The obtained copolymer is once again neutralized by one or more alkalis such as amines such as ammonia, ethylamine, propylamine, ethanolamine, and prophenolamine, sodium hydroxide, potassium hydroxide, magnesium oxide, calcium oxide, and the like. When the carboxyl group of olefin monocarboxylic acid is substituted with ammonia and / or an amine salt, in particular, since the effect of preventing full color staining during offset printing is increased by increasing the strength of the capsule wall film and the capsule coating surface in the presence of a curing agent. It is suitable.

In addition, when 1-95% of the carboxyl groups are substituted with sodium or potassium salts, compatibility with the capsule dispersion is improved, and the superior effect is obtained.

However, if excessive substitution with sodium or potassium salt may cause ground fouling during offset printing, it is preferable to replace 5-50% of the carboxyl group with sodium or potassium salt.

In addition, in the present invention, the carboxyl groups in the copolymer are not necessarily all neutralized by alkali, and the alkali salts of the copolymer containing carboxylic acid are optionally effective, but at least 8 mol% or more of the carboxylic acid in the copolymer to obtain sufficient water solubility. Alkaline salts need to be neutralized to be present.

Such a water-soluble copolymer is a type and composition ratio of the hydrophobic and hydrophilic monomas to be copolymerized, the degree of polymerization, the type and amount of the polymerization aid used, the degree of neutralization or neutralization of the copolymer or the residual monomer in the aqueous solution, inorganic salt, measurement temperature, pH According to the inventors' studies, the surface tension in the aqueous solution of 1% by weight is 40 dyne / cm or more, and more preferably 45-72 dyne /. It is confirmed that what is in the specific range of cm exerts a more excellent effect in improving background fouling.

When the surface tension in an aqueous solution of 1% by weight is less than 40 dyne / cm, the surface activity of the water-soluble copolymer is increased.

)의 표면장력계에 의한 윤환법(輪環法)에 의하여 25℃로서 측정되는 값이며, 증류수를 72dyne/cm로서 보정한 값이다.In addition, the surface tension in the present invention is prepared by 1% by weight of the aqueous solution after 3 hours after the dugne (L. du

It is a value measured as 25 degreeC by the lubrication method by the surface tension meter of (), and the value which corrected distilled water as 72 dyne / cm.

In the present invention, the water-soluble copolymer is generally used as a water-soluble resin having a concentration of 5 to 50% by weight, pH 3-12, and a viscosity of 5 to 100,000 cps. Alkaline salts of water-soluble copolymers having the same surface tension value in terms of the antifouling effect of the ground, which is one of the objects of the present invention, also have a high degree of polymerization indicating a viscosity of 1000 cps or more as an aqueous solution of 20% by weight, for example, a pH value of 8-. It is more suitable to display a high value of 10.

Although the addition amount of the alkali salt of a copolymer is not limited, Usually, it is added in 0.5-50 weight part with respect to 100 weight part of hydrophobic substances in a microcapsule, Preferably it is added in the range of 1-30 weight part.

However, the capsule dispersion to which the curing agent and the alkali salt of the specific copolymer are added is, for example, starch, casein, polyvinyl alcohol, etc. for the purpose of improving safety, fluidity, and adhesion over time according to the prior art. A microcapsule coating liquid is added by adding an adhesive or by appropriately adding so-called stalds such as pulp powder and raw starch powder, dyes and other various preparations.

The obtained capsule coating liquid is applied and dried on a surface of a supporting gas such as paper, synthetic paper, or synthetic film in accordance with a common coating device.

Among properties in the application amount is usually in particular include, but are not limited to 1-15g / m ^2, as dry weight, is applied to a family 2-8g / m ^2.

Thus, in the capsule coating sheet of the present invention, the capsule coating layer is reinforced remarkably with the addition of a specific water-soluble copolymer, and the improvement in moisture resistance, the integrity of the capsule core material, the mechanical strength, and the like. The effect is confirmed.

Therefore, when wet offset printing the capsule-coated surface, not only the problem of background fouling is eliminated, but also the printing of the so-called middle paper on the color-coated stain or colorant-coated surface confirmed when printing by winding method. Since the printed ink is wound before it is completely dried, the improvement effect is also confirmed for the problem that oily core material in a capsule is extracted by the volatile solvent in the printing ink component.

The present invention will be described in detail with reference to the following Examples, which, of course, are not limited thereto.

In each example, the parts and parts indicate parts by weight and parts by weight unless otherwise indicated.

Example 1-10 Symmetry Example (1-6)

[Production of Colorant Coated Paper]

－메틸 벤질 살리실산의 아연염 70부와 스킨렌－

－메틸, 스티렌의 공중합체 30부를 150℃로 가열된 압출기로서 용융혼합하고, 상온으로 냉각후 분쇄하여 정색제를 얻었다.3.5 d

-70 parts of zinc salt and methylene of methyl benzyl salicylic acid-

30 parts of copolymers of -methyl and styrene were melt-mixed with the extruder heated at 150 degreeC, cooled to room temperature, and pulverized, and the colorant was obtained.

20 parts of this coloring agent, 25 parts of zinc oxide, 30 parts of aluminum hydroxide, and 25 parts of activated clay were dispersed in 400 parts of water containing 5 parts of 20% polyacrylic acid sodium hydroxide solution and 20 parts of 10% polyvinyl alcohol aqueous solution. Dispersion was performed as a sand grind.

40 parts of 20% oxidized starch solution and 30 parts of carboxyl group-modified skinene butadiene latex (48% concentration) were added to this system to obtain a colorant coating liquid.

This colorant coating liquid was applied as an air knife coater on one side of a 40 g / m ² base paper so as to have a dry weight of 6 g / m ² , and further calendered to obtain a colorant coated paper.

[Composition of Capsule Dispersion (A)]

30 parts of the acid-treated gelatin was added to 270 parts of water, and left to stand for 1 hour, and then 200 parts of water were added and heated to 60 ° C to obtain an aqueous solution of gelatin.

Separately, 3 parts of crystal biorelagutone and 1 part of benzoyloicomethylene blue are dissolved in 100 parts of diisopronyl naphthalene, and this is added to an aqueous solution of gelatin and stirred to disperse the emulsion so that the average particle diameter remains 5 µm. It was.

Next, 300 parts of a 10% aqueous solution of gum arabic was mixed in the above-mentioned emulsion, and 200 parts of water was added thereto. Then, the pH of the system was adjusted to 4.1 as acetic acid to form a coreselbate film around the oiled site, followed by vigorous stirring. After cooling the temperature of the system to 10 ° C and gating the core selvaate, 5 parts of glutaraldehyde (GA 50, Nangase Industries Co., Ltd.) was then added, and the pH was adjusted to 9.5 as a 5% NaOH aqueous solution. Then, the mixture was stirred for 10 hours to obtain a capsule dispersion.

Most of these capsules were mononuclear capsules.

[Composition of Capsule Dispersion Liquid (B)]

65 parts of acid-treated gelatin of the isoelectric point 8.0 were added to 585 parts of water, and it left for 10 hours as 10 degreeC, and heated and melt | dissolved at 60 degreeC.

Separately, 5.2 parts of crystal bioretragutone and 2.6 parts of benzoyloicomethylenevolume were dissolved in a mixed oil of 78 parts of kerosene and 182 parts of isopropyl naphthalene, and heated to 60 ° C., and then emulsified as a homomixer in an aqueous solution of gelatin as described above. The remains of an average particle diameter of 3.0 mu were obtained.

1,300 parts of 55 degreeC warm water was added to this emulsion, and again 130 parts (10% of gelatin weight ratio) of 5% aqueous solution of carboxyl group methylcellulose (average degree of polymerization 160, substitution degree 0.6) were added.

While stirring was continued, 10% caustic soda aqueous solution was added to adjust the pH of the system to 5.4.

After dropping the liquid temperature to 10 ° C. while stirring, the particle size distribution of the capsule was measured as a Coulter Counter. As a result, the average particle diameter was 8.2 μl in binucleated capsules.

Next, stirring was continued while maintaining the liquid temperature at 10 ° C, 13 parts of a 50% aqueous solution of glutaraldehyde was added, and 10% aqueous sodium hydroxide solution was further added to adjust the pH of the system to 6.0 to obtain a capsule dispersion.

[Composition of Capsule Dispersion (C)]

100 parts of alkyl biphenyl which melt | dissolved 3 parts of crystalviolet ragutones in the aqueous solution (50 degreeC) of 25 parts of acid treatment gelatins of the isoelectric point 8.5 and 250 parts of water were emulsified, and the emulsion of 3 micrometers of average particle diameters was obtained.

An aqueous solution consisting of 25 parts of gum arabic and 250 parts of water was added and mixed with the emulsion, and then 1770 parts of water and 14 parts of a 5% aqueous solution of polyvinyl methyl ether and maleic anhydride copolymer were added and mixed, and preserved at 45 ° C. The pH of the system was adjusted to 4.2 by slowly adding 10% aqueous acetic acid solution by stirring.

Next, the temperature of the system was lowered to 10 DEG C, 25 parts of 10% aqueous formaldehyde aqueous solution was added, and the pH of the system was further adjusted to 10.0 as 5% aqueous sodium hydroxide solution to obtain a dispersion of microcapsules.

This capsule dispersion liquid was a dispersion of binuclear capsules with an average particle diameter of 9 mu.

[Production of Capsule Coated Paper]

As described in Table-1, the alkali salts of the copolymer and various auxiliaries were added to the dispersions of the capsules obtained as described above, respectively, to obtain 16 kinds of capsule coating liquids.

In Example (5), the alkali salt of the copolymer was added to the capsule dispersion simultaneously with the glutaraldehyde as a curing agent.

In the symmetric example (1), the dispersibility was remarkably bad in the capsule dispersion of the copolymer and did not become a capsule paint.

In addition, in (5), the alkali salt of a copolymer is not added all symmetrically.

In addition, the capsule dispersion obtained in the symmetric example (6) was obtained in the same manner as the dispersion liquid (B) except that glutaraldehyde was not added and pH adjustment as caustic soda was not performed in the composition of the capsule dispersion (B). ) Is used.

The 15 kinds of capsule coatings obtained above were coated on an uncoated surface of the colorant sheet thus obtained so as to have a dry weight of 5 g / m ² , thereby obtaining a heavy paper rolled 2000 m in width of 394 mm.

[Evaluation test]

Evaluation test was done about the obtained heavy paper according to the following evaluation methods, and the result was written together to Table- (1).

(1) background fouling test

It was determined as a printing amount (m) by which 1000 m ruled line printing was performed on the capsule-coating surface of the following conditions by the business form printing machine (Made by Akira, 17 BH type) as a wet offset printing system.

Ink: Nuyu Champion Red (manufactured by Nippon Ink Co., Ltd.)

Soaking Water: Municipal Tap Water

Tension: 200 g / cm

Print Speed: 100m / min

(2) Full color stain test

A business foam press (manufactured by Akira Co., Ltd., 17 BH type) is used to print a graphic pattern on the color-coated application surface under the following conditions using the offset offset printing method, complete with 300m winding, and etch for 48 hours at room temperature and atmospheric pressure. It determined by visually seeing the state of the fouling of the coloring agent application surface of the part of about 100 m.

Judgment criteria ◎ We could not confirm the leading edge fouling.

극히 약간 오손이 발생하고 있다.

Very little fouling is occurring.

× Color staining is occurring.

×× Color staining has occurred on the entire surface.

Ink: Nuyu Champion Red (manufactured by Nippon Ink Co., Ltd.)

Soaking water: 3% aqueous solution of the etching solution EU-1 (made by Fuji Photographic Film) for PS board

Tension: 400 g / cm

Print Speed: 100m / min

In the table, the neutralization ratio of carboxylic acid is expressed as the proportion of the carboxyl groups neutralized as NaOH, KOH, NH ₄ OH and amine (propphenolamine), respectively, relative to the total carboxyl groups in the copolymer.

In addition, the alkali salt addition amount of the copolymer was shown as a weight part with respect to 100 weight part of hydrophobic substances contained in a microcapsule.

In addition, raw starch described in the preparation section is classified as wheat starch particles with 20-30μ average particle diameter, and starch oxide is starch pool made of 20% aqueous solution, respectively. Is displayed.

Similarly, the hydroxyl group ethylcellulose casein was used also as aqueous solution, and the solid content was shown.

[Examples 11-20 and 7-12 for Symmetry]

When the surface tension of the water-soluble copolymer was 40 dyne / cm or more as an aqueous solution of 1% by weight, the following evaluation test was carried out to confirm that an excellent effect was particularly exhibited in the improvement of the background fouling.

Further, the colorant coated paper and the capsule dispersion were prepared in the same manner as in the case of Example 1-10 described above, and an alkali salt of the copolymer and various preparations were added to the capsule dispersion as described in Table (2), respectively. 16 capsule coating liquids were obtained.

In Example 5, the alkali salt of the copolymer was added to the capsule dispersion simultaneously with glutaraldehyde as a curing agent.

The 16 sheets of the capsule coating obtained were coated on an uncoated surface of the colorant sheet thus obtained so as to have a dry weight of 5 g / m ² , and a heavy paper rolled 2000 m in width of 394 mm was obtained.

[Evaluation test]

Evaluation tests are carried out on the obtained heavy paper according to the following evaluation methods, and the results are written together in Table (2).

1.Based contamination test

The printing amount at which the generation of background fouling was remarkable was determined by performing a 1000 m ruled line printing using a business foam printer (manufactured by Akira Co., Ltd., 17 BH type) on the capsule coating surface under the following conditions as the offset offset printing method.

Ink: Nuyu Champion Red (made by Nippon Ink Co., Ltd.)

Compound: 100 parts by weight of CP compound (manufactured by Nippon Ink Co., Ltd.) was blended.

Soaking water: 0.5% aqueous solution of the etching solution EU-1 (manufactured by Fuji Photo Film Co., Ltd.) for PS board

Tension: 200 g / cm

Print Speed: 100m / min

In addition, the test conditions described above are tests for confirming the influence of the surface tension of the water-soluble copolymer, and thus, in the case of the above examples 1-10 and symmetry, the test conditions were more easily tested than the test conditions. .

Therefore, a compound is mix | blended with ink as mentioned above, and wet water mentioned above is used also for wet water.

In the non-neutralized carboxylic acid in the table it is expressed as a proportion of each of NaOH, KOH, NH ₄ OH, amine (Pro phenolic amine) and CaO, the carboxyl group neutralized as MgO based on the total carboxyl groups of the copolymer.

In addition, the addition amount of the alkali salt of a copolymer was expressed as weight part with respect to 100 weight part of hydrophobic substances contained in a microcapsule.

Raw starch as described in the preparation section is classified as wheat starch particles with an average particle diameter of 20-30μ, and starch oxide is a starch pool made of 20% aqueous solution. It is displaying.

Similarly, hydroxyl group ethyl cellulose and casein were also used as aqueous solution, and the solid content was shown.

TABLE 1

TABLE 2

Claims (1)

A gelled hydrophilic colloidal material containing fine particles of hydrophobic material and containing (a) a curing agent and (b) at least one olefin monocarboxylic acid in a dispersion of microcapsules made of wall material A recording sheet formed by applying a coating solution containing an alkali salt of a water-soluble copolymer to the surface of a supporting gas.