JPH05287695A - Surface treating agent for paper and paper surface treatment using the same - Google Patents

Abstract

PURPOSE:To provide the subject low-viscosity treating agent easy to use, highly compatible with pastes, and capable of enhancing the surface strength of paper or paperboard, comprising a cationic aqueous emulsion prepared by incorporating a cationic polymer in e.g. a copolymer of a vinyl monomer and unsaturated carboxylic acid. CONSTITUTION:The objective treating agent having the above-mentioned advantages comprises a cationic aqueous emulsion prepared by incorporating (A) 0.01-9wt.% of a cationic polymer such as cationic starch, cationic cellulose or cationic vinyl polymer in copolymerization or after copolymerization of (B) 20-60wt.% of a vinyl monomer component consisting of a mixture of a lower fatty acid vinyl ester (e.g. vinyl acetate) and another monomer copolymerizable therewith (e.g. methyl methacrylate) with (C) 0.1-15 pts.wt., based on 100 pts.wt. of the component B, of an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid or cinnamic acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper surface treating agent and a paper surface treating method. More specifically, when copolymerizing a vinyl monomer and an unsaturated carboxylic acid, it contains a cationic aqueous emulsion obtained by coexisting a cationic polymer, and the viscosity of the paste solution is low without the need for dissolution, Moreover, the present invention relates to a paper surface treating agent which improves the surface strength of paper and paperboard and has good compatibility with a sizing agent such as oxidized starch, and a paper surface treating method using the same.

[0002]

2. Description of the Related Art In the production of paper and paperboard, the use of hardwood has been increasing in place of high quality softwood in recent years due to a decrease in forest resources, which are raw materials for papermaking. However, it has various problems. In particular, the fibers of paper contain a large amount of duct cells that are difficult to be beaten, and this tends to cause so-called "Bessel pick" that peels off during printing and gives white spots to the printed image. In addition, the utilization rate of recycled paper or the recycling rate is increased for the purpose of resource saving, and the ratio of fine particles in the raw material for papermaking is increasing.

By the way, the recent development of printing technology is remarkable, and with the increase in printing speed and quality,
Printing papers are required to have high printability.

Surface treating agents for the purpose of increasing the surface strength of paper and improving printability include starch derivatives such as conventional starch and oxidized starch, cellulose derivatives such as carboxymethyl cellulose, polyvinyl alcohol and anion-modified poly. There are natural or synthetic water-soluble polymer compounds such as acrylamide, and among them, oxidized starch and polyvinyl alcohol are often used.

[0005]

However, conventional surface treatment agents such as oxidized starch and polyvinyl alcohol require complicated operations such as heating and dissolution, and have problems in use such as high viscosity of the paste solution. In addition to the recent demands for high printability, satisfactory results cannot be obtained. Further, in thin paper, there is a case where polyvinyl alcohol is mixed with oxidized starch for the purpose of exerting a good balance between cost and various physical properties, but the compatibility of both is poor and aggregates are formed, which becomes a faint. Contamination occurs on paper machine parts such as coating rolls. As a result, the stains may be transferred to the product, the surface smoothness of the paper may be impaired, and the paper may be broken in some cases, resulting in a problem that the productivity is significantly reduced.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that when a vinyl monomer and an unsaturated carboxylic acid are copolymerized, a cationic polymer is allowed to coexist. By using the surface treatment agent for paper containing the obtained cationic aqueous emulsion, it is not necessary to dissolve it by heating, the viscosity of the agent is low, and the surface strength of paper and paperboard is improved. The inventors have found that the compatibility with the can be improved and completed the present invention.

That is, the present invention contains a cationic aqueous emulsion obtained by coexisting a cationic polymer when copolymerizing a vinyl monomer and an unsaturated carboxylic acid. The present invention provides a treating agent and a surface treating method characterized by performing surface treatment of paper and paperboard using such a surface treating agent for paper.

The cationic aqueous emulsion used in the present invention is, for example, the cationic fiber paste disclosed in Japanese Patent Publication No. 60-707, and the weaving disclosed in Japanese Patent Application Laid-Open No. 2-6667. It is a cationic paste base.
However, the paper surface treatment agent and the paper surface treatment method of the present invention are completely different in the addition amount and usage method from those for textiles such as clothes and for weaving.

On the other hand, JP-A-61-285258 describes that a cationic latex using a cationic polymer such as cationic starch as a protective colloid can be used as a papermaking agent. No specific use cases are disclosed.

On the other hand, the surface treating agent for paper and the method for surface treating of the present invention are such that the cationic aqueous emulsion is applied to the paper after the paper layer is formed, the size press, size tab, gate roll coater, calender, etc. It is used as compared with natural or synthetic water-soluble polymer substances such as starch and starch derivatives, cellulose derivatives, polyvinyl alcohol and polyacrylamide, which have been conventionally used in the art by coating with and using as needed. It has been found that it exhibits excellent surface strength imparting property without difficulty.

Paper and paperboard for the purposes of this invention include sheet stocks and molded products made from fibrous cellulosic materials which can be derived from both natural and synthetic sources. Also, sheet-like materials and molded products made of a combination of cellulosic and non-cellulosic materials derived from mineral fibers such as asbestos and glass, and synthetic materials such as polyamide resin fibers, polyester resin fibers and polyacrylic resin fibers. Is also included.

Vinyl monomer used in the present invention
(A) vinyl acetate, vinyl butyrate, a lower fatty acid vinyl ester such as vinyl propionate, preferably vinyl acetate is exemplified first, but further, the following compound groups shown in the group (1) ~ (6), Monomers copolymerizable with these lower fatty acid vinyl esters, preferably vinyl acetate [wherein lower fatty acid vinyl ester: the following copolymerizable monomers = 8
0:20 to 100: 0 (weight ratio)] is also used. (1) Acrylic acid such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, etc.
Alkyl esters of methacrylic acid (2) Diesters of α, β ethylenically unsaturated dicarboxylic acids, such as dibutyl malate, diethyl malate and their corresponding fumarates, itacolates, citraconates (3) styrene, ethylene (4) vinyl chloride Such as vinyl halides (5) vinylidene halides such as vinylidene chloride (6) α, β ethylenically unsaturated dicarboxylic acid amides and their N-alkylol derivatives such as acrylamide and N-methylolamide As the monomer copolymerizable with the body, an alkyl ester of acrylic acid or methacrylic acid and ethylene are preferable.

The unsaturated carboxylic acid (B) used in the present invention includes acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, aconitic acid, sorbic acid, cinnamic acid, α-chloro. In addition to acids such as sorbic acid, citraconic acid and p-vinylbenzoic acid, there may be mentioned alkyl half esters, partial esters or partial amides of unsaturated polycarboxylic acids such as maleic acid, fumaric acid and itaconic acid. Examples of unsaturated polycarboxylic acid alkyl half esters are monomethyl itaconate, monobutyl itaconate, monomethyl fumarate, monobutyl fumarate,
Examples include lower alkyl half-esters having 1 to 6 carbon atoms such as monobutyl maleate.

Preferred examples of these unsaturated carboxylic acids include acrylic acid, methacrylic acid, crotonic acid,
Maleic acid, and alkyl half-esters, partial esters or partial amides of unsaturated polycarboxylic acids.

The cationic polymer (C) used in the present invention is a cationic starch or a cationic cellulose (particularly preferably water-soluble and having a quaternary ammonium cation group as the cationic group), a cationic vinyl polymer. , A ring-closing polymer of a cationic diallyl compound, and the like. Moreover, one kind may be used alone, or two or more kinds may be used as a mixture.

As the cationic starch or the cationic cellulose, for example, those represented by the following formula (1) are preferable.

[0017]

[Chemical 1]

(In the formula, A: starch residue or cellulose residue R: alkylene group or hydroxyalkylene group R ₁ , R ₂ , R ₃ : the same or different, alkyl group, aryl group, aralkyl group or formula The nitrogen atom therein may be included to form a heterocycle.

X: anion (chlorine, bromine, iodine, sulfuric acid,
Sulfonic acid, methyl sulfuric acid, phosphoric acid, nitric acid, etc.) i: a positive integer).

Such a cationic starch is obtained, for example, by reacting raw starch or modified starch from corn, potato, tapioca, wheat, rice or the like with glycidyltrimethylammonium chloride or 3-chloro-2-hydroxypropyltrimethylammonium chloride under alkaline conditions. You can get it. Also, add dimethylaminoethylated starch to 4
It can also be obtained by grading. It can also be obtained by reacting starch with 4-chlorobutenetrimethylammonium chloride. On the other hand, cationic cellulose can be obtained, for example, by subjecting hydroxyethyl cellulose to the above reaction.

The cationic substitution degree of the cationic starch or the cationic cellulose is preferably 0.01 to 1, that is, 0.01 to 1, preferably 0.02 to 0.5 cationic groups are introduced per anhydroglucose unit. If the degree of substitution is less than 0.01, the effect of the present invention is not sufficient, and the degree of substitution may exceed 1, but it is preferably 1 or less from the viewpoint of reaction yield.

The above-mentioned cationized starch and cationic cellulose have functional groups such as an ether group such as a hydroxyalkyl group and an ester group such as an acetyl group for the purpose of lowering the molecular weight and preventing aging unless the effects of the present invention are impaired. A group may be introduced.

Further, examples of the cationic vinyl polymer include those represented by the following formulas (2) to (5).

[0024]

[Chemical 2]

(In the formula, R _{4 is a} hydrogen atom or a methyl group R ₅ , R ₆ and R _{7 are the} same or different and are a hydrogen atom, an alkyl group having 1 to 22 carbon atoms or a substituted alkyl group Y: an oxygen atom Or an NH group in an amide bond Z: an alkylene group having 2 to 6 carbon atoms or a hydroxyalkylene group X: represents the same as the formula (1))

[0026]

[Chemical 3]

(In the formula, R ₈ , R ₉ and R _{10 are the} same or different and represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a substituted alkyl group X: the same as in the formula (1))

[0028]

[Chemical 4]

(In the formula, X is the same as the formula (1)) The substituent of the above-mentioned substituted alkyl group includes an OH group and a halogen.

[0030]

[Chemical 5]

Examples of the ring-closing polymer of the cationic diallyl compound include those represented by the following formula (6).

[0032]

[Chemical 6]

(Wherein R ′ and R ″ are the same or different and represent an alkyl group or substituted alkyl group having 1 to 2 carbon atoms X: an anionic group), the viscosity of an aqueous solution of the cationic polymer (C) is 1%
In the case of an aqueous solution, 5-1000 cps (centipoise) (20 ° C.), preferably 10-500 cps is good.

In the present invention, the relative contents of the three components (A), (B) and (C) are such that when the vinyl monomer is contained in the aqueous emulsion in an amount of 20 to 60% by weight, The cationic polymer (C) for adsorbing the compound on the surface of paper is 0.01-9% by weight, preferably 0.2-
5% by weight, and the unsaturated carboxylic acid (B) copolymerized with the vinyl monomer is 0.1% by weight based on 100 parts by weight of the vinyl monomer (A).
It is 1 to 15 parts by weight, preferably 0.2 to 5 parts by weight. If the absolute content of unsaturated carboxylic acid (B) increases (if it exceeds 15 parts by weight with respect to (A)), a large amount of aggregates are generated during emulsion polymerization, and the stability of the system is lost, resulting in an aqueous emulsion. The dispersion stability of is a problem. Also, unsaturated carboxylic acid (B)
If the absolute content of () is less than 0.1 part by weight with respect to (A), the adhesion of the cationic polymer to the vinyl monomer and unsaturated carboxylic acid copolymer will be weakened and the effect of the present invention will be reduced. Can be

In the present invention, when a vinyl monomer and an unsaturated carboxylic acid are copolymerized or a cationic polymer is allowed to coexist after the copolymerization, but when a vinyl monomer and an unsaturated carboxylic acid are copolymerized. The following various components may be present together in the required amounts depending on the purpose.

For example, the cationic monomer (D) can be used as a regulator of the particle size distribution of the copolymer compound. The cationic monomer is preferably a cationic monomer having at least one nitrogen atom and at least one double bond in the molecule,
For example, the structures represented by the following formulas (7) to (10) can be given.

[0037]

[Chemical 7]

(In the formula, R ₁₇ represents a hydrogen atom or a methyl group, R ₁₈ , R ₁₉ and R ₂₀ are the same or different and represent a hydrogen atom or an alkyl group having 1 to 22 carbon atoms or a substituted alkyl group. , Y represents an oxygen atom or an NH group in an amide bond, Z represents a hydroxyalkylene group or an alkylene group having 2 to 6 carbon atoms, X represents an anion, R ₁₈ , R ₁₉ and R
₂₀ may mutually contain N and may form a ring. )

[0039]

[Chemical 8]

(In the formula, R ₂₁ represents a hydrogen atom or a methyl group, R ₂₂ , R ₂₃ and R ₂₄ are the same or different and represent a hydrogen atom or an alkyl group having 1 to 2 carbon atoms or a substituted alkyl group. , X represents an anion.)

[0041]

[Chemical 9]

Of the above-mentioned ones, more preferred is
They are vinylbenzyltrimethylammonium chloride [general formula (8)] and acrylic acid ester or methacrylic acid ester of hydroxyalkyl trialkylammonium salt [general formula (7)]. The amount of the cationic monomer (D) added is 0 to 2% by weight based on the cationic aqueous emulsion,
It is preferably 0.02 to 1% by weight.

Further, a surfactant is used as an emulsifier.
Examples of the cationic surfactant include alkyl trimethyl ammonium salt, dialkyl dimethyl ammonium salt, alkyl dimethyl ethyl ammonium salt, alkyl dimethyl benzyl ammonium salt, alkyl pyridinium salt, alkyl quinolinium salt, alkyl isoquinolinium salt, stearyl. Amidomethylpyridinium salt, acylaminoethylmethyldiethylammonium salt, acylaminoethylpyridinium salt, alkoxymethylpyridinium salt, 1-methyl-1-acylaminoethyl-2-
Examples thereof include alkylimidazoline, diacylaminopropyldimethylammonium salt, diacylaminoethyldimethylammonium salt, dialkyldi (polyoxyethylene) ammonium salt and dialkylmethylpolyoxyethyleneammonium salt.

As the anionic surfactant, a higher fatty acid alcohol sulfate represented by a sodium or potassium salt of a sulfuric acid ester of a C _{5 to} C ₁₈ alcohol such as lauryl alcohol, a sodium or potassium salt of a C _{8 to} C ₁₄ fatty acid. ,
Ethanolamine salts such as triethanolamine, such as triethanolamine oleate, triethanolamine stearate, funnel oil, sulfone compounds such as sulfated ricinoleic acid, sodium t-octylbenzene sulfonate, sodium t-octylphenol sulfonate. Examples of sulfonated alkylaryl compounds include:

Examples of nonionic surfactants are alkylphenoxypolyethoxyethanols having C _{7 to} C ₁₈ alkyl groups and 9 to 30 or more ethylene oxide units,
For example, heptylphenoxypolyethoxyethanol, octylphenoxypolyethoxyethanol, methyloctylphenoxypolyethoxyethanol, nonylphenoxypolyethoxyethanol, dodecylphenoxypolyethoxyethanol, or the like, or a polyethoxyethanol derivative of alkylphenol linked with a methylene bond, nonyl, dodecyl, Mercaptan such as tetradecyl or C ₈ ~
C ₁₈ Alkylthiophenol and sulfur-containing emulsifiers with the required amount of ethylene oxide condensed, lauric acid, myristic acid, palmitic acid, oleic acid, ethylene oxide derivatives of long-chain carboxylic acids such as tall oil mixed acids, hydrophobic carbonization It is an ethylene oxide derivative of an etherified or esterified polyhydroxy compound having a hydrogen chain. As the nonionic surfactant, those having an HLB of 12 to 19, preferably 15 to 18 are used.

Further, a protective colloid may be used as an emulsifier. Examples of protective colloids that can be used include polyvinyl alcohol, hydroxyethyl cellulose, starch and the like. However, when a protective colloid is used, it is usual to use a surfactant together.

Further, in order to obtain a stable emulsion for a long period of time, (E) a nonionic water-soluble polymer can be used in combination. Examples of the nonionic water-soluble polymer include polyvinyl alcohol, modified starch and cellulose derivatives. The modified starch that can be used in the present invention is a water-soluble modified starch, and examples thereof include hydroxyethylated starch and hydroxypropylated starch. The polyvinyl alcohol that can be used in the present invention is a vinyl acetate homopolymer or a complete or partial saponification product of a copolymer of vinyl acetate and another monomer, or a polyvinyl alcohol derivative obtained by modifying these with an aldehyde or the like. The nonionic cellulose derivative that can be used in the present invention is water-soluble hydroxyalkylated cellulose or alkylcellulose. For example, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose (methylation degree 10%) and the like can be mentioned. These properties include 5% aqueous solution viscosity
It is preferable that it exhibits 5 to 10,000 cps at 30 ° C. The addition amount of these is 0 to 10% by weight, preferably 1.0 to 4.0% by weight, based on the water-soluble cationic polymer emulsion system.
Is.

The nonionic water-soluble polymer used as the component (E) is added during or after the reaction between the components (A) and (B).
(C) It is preferably used together with a cationic polymer.

As the polymerization initiator used for the copolymerization to obtain the cationic aqueous emulsion of the present invention, 2,2'-azobis (2-amidinopropane) hydrochloride is the best, but other hydrogen peroxide, t-butyl Hydroperoxide,
Cumene hydroperoxide, t-butyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, peracetic acid, perbenzoic acid and the like can be used. The amount of addition is 0.01 to 5.
It is preferably used in the range of 0 weight. Reaction temperature is 40-120
℃, preferably 50 ~ 90 ℃, the pH during polymerization is 3 ~ 9,
It is preferably carried out at 4 to 8. At this time, as a buffering agent, an inorganic salt such as sodium carbonate, sodium bicarbonate, sodium orthophosphate, dibasic sodium phosphate, monobasic sodium phosphate, sodium chloride or sodium sulfate is added in an amount of 0 to 2,
It is preferable to use 0.1 to 1% by weight.

Therefore, the raw material composition for producing the cationic aqueous emulsion of the present invention preferably has the following respective component contents. (A) Vinyl monomer; 20 to 60% by weight, more preferably 25
To 50% by weight (B) unsaturated carboxylic acid; 0.1 to 15 parts by weight, and more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of vinyl monomer (C) cationic polymer; 0.01 to 9% by weight, and Preferably 0.2 to 5% by weight (D) Cationic monomer; 0 to 2% by weight, more preferably 0.02 to 1% by weight Surfactant (nonionic surfactant, cationic surfactant or anionic Surfactant); 0 to 5% by weight, more preferably 0.2 to 2% by weight (E) Water-soluble nonionic polymer; 0 to 10% by weight, more preferably 1 to 4% by weight. 0.01-5% by weight with respect to the quantity
More preferably 0.02 to 1% by weight-inorganic salt; 0 to 2% by weight, further preferably 0.1 to 1% by weight-water etc .; balance.

That is, the preferred aqueous emulsion of the present invention is obtained by emulsion polymerization with the composition as described above (however, the cationic polymer may be added after the completion of emulsion polymerization), but the addition method is to add all components at the same time. Although the reaction may be carried out by the reaction, the method is more preferable, in which the vinyl monomer is gradually added to a reaction vessel charged with a substance other than the vinyl monomer.

In the emulsion polymerization method for obtaining the cationic aqueous emulsion according to the present invention, when the vinyl monomer is copolymerized with the copolymerizable unsaturated carboxylic acid, the cationic polymer coexists or does not coexist (( In this case, it is a method of adding the copolymer to the copolymer system after completion of the emulsion copolymerization. The following method is illustrated as a more preferable method. That is, it is a method of emulsion-copolymerizing a vinyl monomer other than the cationic monomer and an unsaturated carboxylic acid using a surfactant in the presence of the cationic polymer in an aqueous nonionic polymer solution.

Regarding the synthesis of the copolymer, the effect that the size of the polymer particles can be made arbitrary by using the cationic monomer, by the amount used, or by the structure of the cationic monomer used Is exhibited together with other effects such as a stabilizing effect, and the cationic polymer has a stabilizing effect such as a protective colloid for the polymer particles, and also is adsorbed on the polymer particles, so that the polymer particles are formed such as cellulose fibers. It exerts the effect of promoting adsorption to a system that is easily negatively charged in water. Further, the cationic surfactant forms micelles in water to solubilize the vinyl monomer in emulsion polymerization, provides a place for polymerization of the vinyl monomer, and imparts dispersion stability to the resulting polymer. And so on.

The cationic aqueous emulsion according to the present invention, even if it does not contain a water-soluble nonionic polymer such as polyvinyl alcohol, nonionic modified starch or nonionic cellulose derivative, is sufficiently used as a surface treatment agent. Although it is used, it becomes more stable when used together with the water-soluble nonionic polymer.

No particular limitation is imposed on the use of the surface treating agent for paper of the present invention containing the above-mentioned cationic aqueous emulsion, and the above-mentioned surface treating agent for paper is used in the process for producing paper or paperboard. Any conventionally known surface treatment method of coating or impregnating after layer formation can be adopted.
Specifically, 0.01 to 10 g / m ² (solid content), preferably 0.1 to 3 g of a surface treatment agent is applied to the surface of a paper by a size press, size tab, gate roll coater, calender, or the like. / M ² It may be added so that it is applied. It goes without saying that the standard of the coating amount of these surface treatment agents must be adjusted depending on the surface strength required for the target paper. Further, in carrying out the paper surface treating method of the present invention, the paper treating agent according to the present invention may be used alone, and the above-mentioned natural or synthetic water-soluble polymer compound, dye, etc. may be surface-treated. It is also possible to mix and use additives such as agents and defoaming agents in the same coating liquid.

The base paper to which the surface treatment method for paper of the present invention is applied is not particularly limited, and various kinds of paper, paperboard and the like can be used. Further, the surface treatment method for paper of the present invention is hardly affected by pulp, filler, dye, internally added sizing agent, paper strength enhancer, retention improver, pH at the time of papermaking and the like.

[0057]

EXAMPLES The present invention will be specifically described below with reference to production examples, examples and comparative examples, but the present invention is not limited to these examples.

Parts and% in the examples are by weight unless otherwise specified.

Production Example 1 A 5-neck separable flask equipped with a nitrogen gas inlet tube, a stirrer, a constant amount dropping device for monomers, a thermometer, and a reflux condenser was charged with the following formula.

[0060]

[Chemical 10]

Trimethylaminohydroxypropylated starch represented by (nitrogen content 0.6%, viscosity of 1% aqueous solution 40
cps) 30 parts, polyoxyethylene (ethylene oxide addition mole number 35) nonyl phenyl ether 9.0 parts, ion-exchanged water 550 parts are added, dissolved at 80 ° C, cooled to 60 ° C, and then vinyl acetate 20 parts, Polymerization initiator was added to 0.5 parts of 2,2'-azobis (2-amidinopropane) hydrochloride and 20 parts of ion-exchanged water, and the temperature was raised to 70 ° C to start the polymerization. After 20 minutes from the start of polymerization, 12 parts of crotonic acid and vinyl acetate were added for 300 minutes.
A solution prepared by mixing 88 parts was dropped. After the addition was completed, the temperature was raised to 80 ° C. to terminate the reaction.

Production Example 2 A cationic aqueous emulsion was synthesized in the same manner as in Production Example 1 except that the vinyl monomer was changed to 40 parts of crotonic acid and 360 parts of vinyl acetate.

Production Example 3 Using the same experimental apparatus as in Production Example 1, 5 parts of polyvinyl alcohol (partially saponified product, saponification degree 88%, polymerization degree 500), the following formula

[0064]

[Chemical 11]

Trimethylaminohydroxyethylated starch represented by (nitrogen content 0.6%, 1% aqueous solution viscosity 40 cps
) 30 parts and 500 parts of ion-exchanged water are added, dissolved at 80 ° C, cooled to 60 ° C, and then polyoxyethylene (ethylene oxide addition mole number 20) lauryl alcohol 9
Parts, sodium carbonate 0.3 parts, vinyl acetate 20 parts, 2,2′-azobis (2-amidinopropane) hydrochloride 0.5 parts and ion-exchanged water 80 parts were added, and the temperature was raised to 70 ° C. to initiate polymerization. A solution obtained by mixing 12 parts of acrylic acid and 388 parts of vinyl acetate was added dropwise from 300 minutes after starting 20 minutes after the initiation of polymerization. After the addition was completed, the temperature was raised to 80 ° C. to terminate the reaction.

Production Example 4 A cationic aqueous emulsion was synthesized in the same manner as in Production Example 3 except that the vinyl monomer was changed to 12 parts of itaconic acid and 388 parts of vinyl acetate.

Production Example 5 12 parts of vinyl monomer monoethyl maleate and vinyl acetate were used.
A cationic aqueous emulsion was synthesized in the same manner as in Production Example 3 except that the amount was changed to 388 parts.

Production Examples 6 to 8 Using the same apparatus as in Production Example 1, 37.5 parts of the cationic polymer shown in Table 1, polyvinyl alcohol (partial saponification degree 79%,
Polymerization degree 1600) Add 6.0 parts and ion-exchanged water 500 parts to 80
After dissolving at 60 ° C and cooling to 60 ° C, 50 parts of vinyl monomer shown in Table 1 and 20 parts of crotonic acid and, if necessary, ionic surfactant or cationic monomer shown in Table 1 Add 10 parts of sodium carbonate, add 0.1 part of sodium carbonate, 0.5 part of 2,2'-azobis (2-amidinocyclopropane) hydrochloride or cumene hydroperoxide, and 100 parts of ion-exchanged water. did. 20 minutes after the start of polymerization
400 parts of vinyl monomer was continuously added dropwise over 300 minutes. After completion of the dropping, the temperature was raised to 80 ° C. to terminate the reaction.

[0069]

[Table 1]

Comparative Production Example 1 The same cationic aqueous emulsion as in Production Example 1 was synthesized, except that crotonic acid was not used, except for the polymerization composition.

Comparative Production Example 2 20% by weight of crotonic acid was added to 100% by weight of vinyl monomer.
A cationic aqueous emulsion having the same polymerization composition as in Production Example 3 was used.

Comparative Production Example 3 Polyvinyl alcohol having a degree of polymerization of 1700 and a degree of saponification of 98 mol%
100 parts and 1900 parts of water were heated and dissolved at 90 to 95 ° C. for 2 hours to adjust the solid content concentration to 5%.

Example 1 Using the paper surface treating agents of Production Examples 1 to 8 and Comparative Production Examples 1 to 3, paperboard and neutral electrophotographic transfer paper (neutral PPC paper)
Tables 2 and 3 show the results of comparison of the effect of improving the surface strength and the compatibility with the concomitant drug (oxidized starch) when the surface treatment was performed.

[I] Comparison of Surface Strength Improvement Effects (a) Paperboard Base Paper Preparation-Pulp: NBKP (Canadian Standard Freeness)
450ml) ・ Fixing agent: polyamine polyamide epichlorohydrin resin (commercially available), solid content 0.05% to pulp weight ・ Sizing agent: ketene dimer sizing agent (Cyrene S94
, Kao), solid content 0.5% based on pulp weight ・ Paper strength enhancer: cationic polyacrylamide polymer (commercially available), solid content 0.3% based on pulp weight ・ Fixing pH: 7.5 ・ Order of addition: pulp → Fixing agent → Sizing agent → Paper strengthening agent ・ Papermaking: Tappy square handmade machine ・ Press: 3.5kgw / cm ² × 2 minutes ・ Drying: Rotary dryer, 105 ° C / 1 minute ・ Basis weight: 100g / m ²・ Calendar: Linear pressure 30 kg / cm ² coating ・ Size liquid composition: Surface treatment agent (Table 2); 2.0% ・ Coating amount: Surface treatment agent solid content; 0.15 g / m ²・ Coating machine: Blade coater (flexible trailing blade coater: made by Kumagai Riki) ・ Coating pressure: 5.0kg / cm ²・ Coating speed: 100m / min ・ Coating temperature: 65 ℃ ・ Drying condition: 105 ° C using a rotary dryer Dry in 40 seconds Surface strength measurement ・ Testing machine: RI-1 type printability tester (manufactured by Akira Seisakusho)・ Nip pressure: 5 mm ・ Ink: New MDK process indigo, tack value 18 ± 1
(Manufactured by Toyo Ink Co., Ltd.).

(B) Transfer paper for neutral electrophotography (neutral PPC paper) Base paper preparation ・ Pulp: LBKP (Canadian standard freeness)
・ Filler: Light calcium carbonate (commercial product), added by adjusting the calcium carbonate in the paper to 8% ・ Fixing agent: Cationized starch (commercial product), solid content 0.5% to pulp weight ・ Size Agent: Ketene dimer size agent (Cyrene S94
, Kao), solid content 0.03% based on pulp weight ・ Retention aid: Cationic polyacrylamide polymer (commercially available), solid content 0.02% based on pulp weight ・ Fixing pH: 8.0 ・ Order of addition: pulp → Filler → Fixing agent → Sizing agent → Yield improver ・ Papermaking: Tappy square handmade machine ・ Press: 3.5kgw / cm ² × 2 minutes ・ Drying: Rotary dryer, 100 ° C / 40 seconds ・ Basis weight: 70g / m ²・ Calendar: linear pressure 30kg / cm ² coating ・ Size liquid composition: surface treatment agent (Table 2); 0.7% oxidized starch; 6.3% surface sizing agent (styrene-acrylic resin); 0.2% ・ application Amount: Surface treatment agent solid content; 0.08 g / m ² Oxidized starch; 0.72 g / m ² surface sizing agent; 0.02 g / m ²・ Coating machine: Size press (PROCESSOR P-122: manufactured by Kodak Nagase)・ Coating liquid temperature: 60 ℃ ・ Drying condition: Use a rotary dryer to dry at 105 ℃ for 40 seconds Surface strength measurement Fixed ・ Tester: RI-1 type printability tester (manufactured by Ming Seisakusho) ・ Nip pressure: 5 mm ・ Ink: New MDK process indigo, tack value 18 ± 1
(Manufactured by Toyo Ink Co., Ltd.)

[0076]

[Table 2]

Note) * The surface strength was calculated by counting and averaging the number of paper dropouts from 10 samples of printability test pieces (190 × 20 mm) and converting them into pieces / m ² .

[II] Comparison of Compatibility with Oxidized Starch Production Examples 1 to 8 and Production Comparative Example 1 in 300 ml measuring cylinders
50 g of size liquid is adjusted so that the solid content concentration of the surface treatment agent composition for paper of 3 to 5% and the solid content concentration of oxidized starch are 8%, and an air stone having a diameter of 3 cm is added thereto. .. 60
The foam was allowed to stand at 1 ° C. for 1 hour, and the foam height after 1 hour and the amount of generated aggregates were measured. The amount of aggregates generated was determined by filtering the generated aggregates with a 325-mesh wire net and determining the solid content weight.
Expressed as% solid content. The results obtained are shown in Table 3.
The higher the foam height and the more aggregates, the poorer the compatibility with the oxidized starch. The other test conditions are as shown below.・ Air pump: Aquarium Lamy 500S (manufactured by Five Plan) Air flow rate 800 ml / min ・ Air stone: Use 3 cm diameter

[0079]

[Table 3]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location D21H 19/10 7199-3B D21H 1/34 F 7199-3B 5/00 Z

Claims (8)

[Claims] 1. A cationic aqueous emulsion obtained when (A) a vinyl monomer component and (B) an unsaturated carboxylic acid are copolymerized or (C) a coexisting cationic polymer is present after the copolymerization. A surface-treating agent for paper, characterized by containing. 2. The (A) vinyl monomer component is 20 to 60% by weight,
(B) the unsaturated carboxylic acid is 0.1 to 15 parts by weight per 100 parts by weight of the (A) vinyl monomer, and (C) the cationic polymer is
The surface treating agent for paper according to claim 1, which contains a cationic aqueous emulsion in an amount of 0.01 to 9% by weight. 3. A cationic aqueous emulsion obtained by coexisting (D) a cationic monomer when (A) a vinyl monomer component and (B) an unsaturated carboxylic acid are copolymerized. The surface treating agent for paper according to claim 1 or 2, characterized in that. 4. The surface treating agent for paper according to claim 1, further comprising (E) a water-soluble nonionic polymer. 5. The paper surface treatment according to claim 1, wherein the vinyl monomer component (A) is a mixture of a lower fatty acid vinyl ester and a monomer copolymerizable therewith. Agent. 6. The unsaturated carboxylic acid (B) is acrylic acid,
Methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, aconitic acid, sorbic acid, cinnamic acid, α-
6. One or more selected from the group consisting of chlorosorbic acid, citraconic acid and p-vinylbenzoic acid.
The surface treatment agent for paper according to any one of 1. 7. The cationic polymer (C) is one or more selected from the group consisting of cationic starch, cationic cellulose, cationic vinyl polymers and ring-closing polymers of cationic diallyl compounds. Any one of 6
The surface treatment agent for paper according to the item. 8. A method for surface treatment of paper, which comprises surface-treating paper or paperboard using the surface treatment agent for paper according to any one of claims 1 to 7.