JP4803425B2 - Method for producing resin emulsion for paper processing - Google Patents

Description

  The present invention is a resin emulsion for paper processing that is used by adhering to a base paper by a known processing method such as impregnation method, coating method, spray method, etc., and drying it. The present invention relates to a novel method for producing a paper processing resin emulsion that imparts excellent properties such as strength and heat-resistant yellowing to paper.

  In general, processed paper used for various purposes such as copy paper, form paper, report paper, memo paper, measurement recording paper, slips, etc. is used after a resin emulsion is adhered to a base paper and then dried.

  When the resin emulsion is adhered to the base paper by an impregnation method, coating method, spray method, or other processing method, if the size pressability during processing of the resin emulsion is inferior, a large amount of deposits are generated on the processed paper, resulting in production efficiency. Development of a resin emulsion for paper processing having excellent size pressability has been eagerly desired because it causes deterioration and poor quality of processed paper.

  In order to meet such a requirement, the reaction residue of a monoethylenically unsaturated monomer having 1 to 10% by weight of an acrylonitrile reaction residue as a repeating unit and a nonionic hydrophilic group having a molecular weight of at least 100 as a side chain is provided. A paper composition containing 0.1 to 8% by weight of a polymer containing either 5% by weight or less of a methyl methacrylate reactive residue or an ethylenically unsaturated amide reactive residue is proposed. (For example, refer to Patent Document 1).

  However, the emulsion polymer obtained in Patent Document 1 is still insufficient in mechanical stability such as size pressability when it is impregnated to produce a processed paper, and since acrylonitrile is used, the heat resistance of the processed paper is low. It is inferior to yellowing and has not yet been satisfactory in properties such as strength.

JP 9-324393 A

  An object of the present invention is a resin emulsion for paper processing that is used by being attached to a base paper by a known processing method such as an impregnation method, a coating method, or a spray method, and then dried. It is to provide a novel process for producing a resin emulsion for paper processing that imparts excellent properties such as strength of paper and heat-resistant yellowing.

  As a result of intensive studies to solve the above problems, the present inventors have found that an ethylenically unsaturated monomer having methyl acrylate and / or ethyl acrylate and a sulfonic acid group and / or a sulfonic acid group in the presence of an emulsifier. By the manufacturing method of paper processing emulsion that emulsion-polymerizes ethylenically unsaturated monomers containing a monomer as an essential component, it is excellent in size pressability during processing, strength and heat-resistant yellowing on the processed paper The present inventors have found that a novel resin emulsion for paper processing that imparts the above properties can be obtained.

That is, in the present invention, in the presence of an emulsifier (A), methyl acrylate and / or ethyl acrylate (B) and an ethylenically unsaturated monomer (C) having a sulfonic acid group and / or a sulfonic acid group are essential components. A method for producing a resin emulsion for paper processing characterized by emulsion polymerization of ethylenically unsaturated monomers contained as methyl acrylate and / or ethyl acrylate in the ethylenically unsaturated monomers The content of (B) is 30 to 70% by weight, the content of the ethylenically unsaturated monomer (C) having a sulfonic acid group and / or a sulfonate group is 0.1 to 5% by weight, and the number of carbon atoms is 8 The content of alkyl (meth) acrylate (D) having ˜15 alkyl groups is 1 to 10% by weight, and the content of butyl (meth) acrylate (E) is 9 to 60% by weight. Method for producing paper coating resin emulsion, wherein there is provided a.

  According to the method for producing a resin emulsion for paper processing of the present invention, the obtained resin emulsion is excellent in water retention, for example, even if it is adhered to a base paper by a conventional processing method such as an impregnation method, a coating method, or a spray method. Stable paper processing is possible without the occurrence of flocs (aggregates) that can cause inefficiencies and poor product quality. As a result, size pressability during processing and the strength of the processed paper can be obtained. It is extremely effective in improving properties such as heat-resistant yellowing.

  The matters necessary for carrying out the present invention are described below.

  The method for producing a resin emulsion for paper processing according to the present invention comprises an ethylenically unsaturated monomer having methyl acrylate and / or ethyl acrylate (B) and a sulfonic acid group and / or a sulfonic acid group in the presence of an emulsifier (A). An ethylenically unsaturated monomer containing the body (C) as an essential component is emulsion-polymerized.

  Examples of the emulsifier (A) include an anionic emulsifier, a cationic emulsifier, an amphoteric emulsifier, and a nonionic emulsifier.

  Examples of the anionic emulsifier include alkyl sulfate salts, alkylbenzene sulfonates, fatty acid salts, polyoxyethylene alkyl ether sulfate salts, and the like. Examples of the cationic emulsifier include alkyl amine salts and quaternary ammonium salts; Examples of the amphoteric emulsifier include alkylbetaines and alkylamine oxides; examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, sorbitan fatty acid ester, polyoxyethylene fatty acid ester, and the like. These emulsifiers may be used in combination as long as the object of the present invention is not impaired.

  Among the emulsifiers (A), nonionic emulsifiers are preferable, and among them, polyoxyethylene alkyl ether is particularly suitable for water retention, penetrability, foam breakage, dynamic surface tension reducing ability, and detergency. , And the emulsifying power is preferable.

  The average number of oxyethylene units in the polyoxyethylene alkyl ether is preferably 50 or more per molecule, more preferably in the range of 50 to 150 on average, and still more preferably in the range of 80 to 110 on average. is there. If the oxyethylene unit in the polyoxyethylene alkyl ether is in such a region, the hydrophilic component in the resin emulsion becomes an appropriate amount, it becomes possible to exhibit excellent water retention, and aggregates are formed during paper processing. It does not occur and there is no trouble during production, production efficiency does not decrease, and there is no possibility of causing bad effects such as poor quality of processed paper.

The polyoxyethylene alkyl ether is a generic term for emulsifiers having an oxyethylene unit [— (CH ₂ CH ₂ O) —] in one molecule and an alkyl ether group at the molecular end.

  The number of carbon atoms of the alkyl ether group at the molecular end of the polyoxyethylene alkyl ether is preferably in the range of 8 to 18, more preferably in the range of 10 to 13. The structure may be used and is not particularly limited, and examples thereof include octyl group, decyl group, isodecyl group, lauryl group, tridecyl group, myristyl group, oleyl group, stearyl group, etc. Among these, the point of stability during polymerization To decyl group.

  Furthermore, the polyoxyethylene alkyl ether has a polyoxyethylene unit in one molecule and other polyoxyalkylene units represented by, for example, a polyoxypropylene unit as a nonionic hydrophilic group. May be allowed to coexist as long as they are not hindered.

  The polyoxyethylene alkyl ether used as the emulsifier (A) is used in an amount of 3 to 10 parts by weight with respect to 100 parts by weight as a total of 100 parts by weight of the ethylenically unsaturated monomers used as raw materials for the copolymer used in the production of the resin emulsion. The range is preferably 5 to 8 parts by weight. If the use amount of the polyoxyethylene alkyl ether is within the range, the size press property is excellent, the viscosity of the resin becomes moderate, and there is no possibility of causing trouble in the production process, for example, impregnation method, coating method, spray method, etc. It is excellent in processability in the known processing method.

  In the present invention, in the presence of the emulsifier (A), methyl acrylate and / or ethyl acrylate (B) and an ethylenically unsaturated monomer (C) having a sulfonic acid group and / or a sulfonic acid group are used as essential components. Emulsion polymerization is carried out using the ethylenically unsaturated monomers contained, but the monomer (B) is excellent in copolymerizability, has less unreacted monomer odor, and has less adverse effects on environmental health. Therefore, ethyl acrylate is preferred.

  Next, the ethylenically unsaturated monomer (C) having a sulfonic acid group and / or a sulfonic acid group will be described below.

  By using the ethylenically unsaturated monomer (C) having the sulfonic acid group and / or the sulfonic acid group as essential, water retention of the paper after processing is improved, and an unprecedented excellent size press property is obtained. be able to.

  The monomer (C) is, for example, an ethylenic group having a sulfonic acid group such as acrylamide-t-butyl sulfonic acid, vinyl sulfonic acid, isoprene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, and styrene sulfonic acid. Unsaturated monomers; ethylenically unsaturated monomers having the sulfonate groups (that is, alkali metal bases such as Na and K), and the like. Among these, acrylamide-t-butylsulfonic acid is polymerizable and This is preferable from the viewpoint of excellent water retention of the processed paper. These monomers may be used alone or in combination of two or more.

  The methyl acrylate and / or ethyl acrylate (B) in the ethylenically unsaturated monomers, and the content of the ethylenically unsaturated monomer (C) having a sulfonic acid group and / or a sulfonic acid group are: The monomer (B) is 30 to 99.5% by weight, the monomer (C) is 0.1 to 5% by weight, and preferably the monomer (B) is 40 to 95% by weight. (C) is in the range of 0.5 to 3% by weight. In the copolymer used for the resin emulsion for paper processing, the content of methyl acrylate and / or ethyl acrylate (B) and ethylenically unsaturated monomer (C) having a sulfonic acid group and / or a sulfonic acid group is required. If it is in the range, moderate water retention and excellent size pressability can be obtained.

  In the ethyl acrylate unsaturated monomer (C) having a methyl acrylate and / or ethyl acrylate (B) and a sulfonic acid group and / or a sulfonic acid group, other ethylenically unsaturated monomers described later are used. You may use together in the range which does not deviate from the objective of this invention.

  Further, in the present invention, as the ethylenically unsaturated monomers, the methyl acrylate and / or ethyl acrylate (B) and the ethylenically unsaturated monomer having a sulfonic acid group and / or a sulfonic acid group (C ) And alkyl (meth) acrylate (D) having an alkyl group having 8 to 15 carbon atoms.

  By using three types of the monomer (B), the monomer (C) and the monomer (D) in combination, a hydrophobic group association bond is formed in the resulting resin, and the water retention is further improved. More excellent size pressability can be obtained.

  Examples of the alkyl (meth) acrylate (D) having an alkyl group having 8 to 15 carbon atoms include 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, and an acrylate ester in a commercial product. SL (Mitsubishi Rayon Co., Ltd., a mixture of alkyl methacrylates having 12 and 13 carbon atoms), and the like may be used alone or in combination of two or more. Among these, since both copolymerizability and stability during polymerization are good, alkyl (meth) acrylates having an alkyl group having 12 to 13 carbon atoms are preferable.

  The methyl acrylate and / or ethyl acrylate (B), the sulfonic acid group and / or the ethylenically unsaturated monomer (C) having a sulfonate group, and the alkyl having 8 to 15 carbon atoms. In the (meth) acrylate (D), as described above, other ethylenically unsaturated monomers described later may be used in combination without departing from the object of the present invention.

  The monomer (B), monomer (C), and monomer (D) content in the ethylenically unsaturated monomers is such that the monomer (B) is 30 to 90% by weight, The monomer (C) is in the range of 0.1 to 5% by weight and the monomer (D) is in the range of 1 to 10% by weight, preferably the monomer (B) is in the range of 50 to 70% by weight. (C) is in the range of 0.5 to 3% by weight and monomer (D) is in the range of 5 to 8% by weight. For this, other ethylenically unsaturated monomers can be used in combination, In this case, the content of other ethylenically unsaturated monomers is in the range of 0 to 69% by weight, preferably in the range of 25 to 42% by weight.

  In particular, the copolymer used in the resin emulsion for paper processing includes ethylenically unsaturated monomers as monomer (B), monomer (C) and monomer (D), as well as butyl (meth). By using acrylate (E) in combination, the copolymerizability and the stability during polymerization are further improved, and in particular, it effectively works to adjust the glass transition temperature of the copolymer, and can be applied to a wider range of uses. .

  The content of monomer (B), monomer (C), monomer (D) and monomer (E) in the ethylenically unsaturated monomers is such that monomer (B) is 30 to 90% by weight, monomer (C) 0.1 to 5% by weight, monomer (D) 1 to 10% by weight, and monomer (E) 9 to 60% by weight Yes, preferably 50 to 70% by weight of monomer (B), 0.5 to 3% by weight of monomer (C), 5 to 8% by weight of monomer (D), and monomer ( E) is in the range of 25 to 42% by weight.

  Also in this case, the methyl acrylate and / or ethyl acrylate (B), the ethylenically unsaturated monomer (C) having the sulfonic acid group and / or the sulfonic acid group, and the alkyl group having 8 to 15 carbon atoms. In the alkyl (meth) acrylate (D) and butyl (meth) acrylate (E) which have, you may use together other ethylenically unsaturated monomers in the range which does not deviate from the objective of this invention.

  In the copolymer used in the resin emulsion for paper processing, if the content of methyl acrylate and / or ethyl acrylate (B) is in the range of 30 to 90% by weight, moderate hydrophilicity can be obtained and water retention can be easily ensured. In addition, excellent size pressability can be obtained, and the glass transition temperature (Tg) of the copolymer can be easily adjusted, so that it can be applied to a wide range of paper.

  In the copolymer used for the resin emulsion for paper processing, the content of the ethylenically unsaturated monomer (C) having the sulfonic acid group and / or sulfonic acid group is in the range of 0.1 to 5% by weight. It is easy to develop water retention, size pressability is improved, and the pH of the reaction system is in an appropriate range, and the copolymer has a high reactivity and good stability during copolymerization. Can be easily obtained.

  In the copolymer used for the resin emulsion for paper processing, if the content of the alkyl (meth) acrylate (D) having an alkyl group having 8 to 15 carbon atoms is in the range of 1 to 10% by weight, the amount of the hydrophobic group As a result, the water content becomes moderate due to the associative bond of hydrophobic groups, and the reactivity during copolymerization and the stability during polymerization are excellent, and the desired copolymer can be easily obtained.

  Moreover, in the copolymer used for the resin emulsion for paper processing, if the number of carbon atoms of the alkyl group of the alkyl (meth) acrylate (D) is in the range of 8 to 15, the reactivity during copolymerization becomes moderate, and Excellent stability during polymerization.

  In the copolymer used in the resin emulsion for paper processing, the content of butyl (meth) acrylate (E) in the ethylenically unsaturated monomers is in the range of 9 to 60% by weight, preferably 25 to 42% by weight. Range. If the content ratio of butyl (meth) acrylate (E) is within this range, the glass transition temperature (Tg) can be easily adjusted, and since it has an appropriate amount of hydrophilic components, water retention can be further maintained. Thus, an excellent size press property can be obtained.

  In addition, the above-mentioned monomer (B), monomer (C), monomer (D) and monomer (E) and other ethylenically unsaturated monomers that can be used in combination are, for example, , Phenyl (meth) acrylate, chlorophenyl (meth) acrylate, aminophenyl (meth) acrylate, benzyl (meth) acrylate, vinyl compounds having an aromatic ring with or without substituents such as styrene; methyl methacrylate, ethyl methacrylate, propyl (Meth) acrylates such as (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate; 2,2,3,3-pentafluoroethyl (meth) acrylate, 2,2,3,3-penta Fluorine such as fluoropropyl (meth) acrylate and β- (perfluorooctyl) ethyl (meth) acrylate Ethylenically unsaturated monomers; glycidyl group-containing polymerizable monomers such as glycidyl (meth) acrylate and allyl glycidyl ether; aminoethyl (meth) acrylate, N-monoalkylaminoalkyl (meth) acrylate, N, N Examples include amino group-containing polymerizable monomers such as' -dialkylaminoalkyl (meth) acrylate; acrylonitrile and the like, and these may be used alone or in combination of two or more.

  However, when acrylonitrile is used as other ethylenically unsaturated monomers, the heat-resistant yellowing of the resulting processed paper may tend to decrease slightly, so it is preferable to keep the amount used to a minimum. .

  As a raw material for the copolymer used in the resin emulsion for paper processing, any compound having an ethylenically unsaturated bond capable of addition polymerization can be used. For example, various (meth) acrylic acid esters; (meth) acrylic Acid monomers such as acid and itaconic acid; polyfunctional unsaturated monomers such as ethylene glycol (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, trimethylolpropane trimethacrylate, diallyl phthalate, etc. These may be used alone or in combination of two or more.

  The copolymer used in the resin emulsion for paper processing can be synthesized by a known method, and the polymerization method is not particularly limited, but emulsion polymerization is particularly preferable.

  The copolymer used in the resin emulsion for paper processing preferably has a calculated glass transition temperature (hereinafter referred to as “calculated Tg”) in the range of −20 to 20 ° C.

  If the calculated Tg of the copolymer used in the resin emulsion for paper processing is a relatively low temperature range of −20 to 20 ° C. and a wide range, it is suitable for processing paper and excellent in winding the processed paper. Both anti-blocking properties can be imparted and is extremely useful for processed paper such as PPC paper (Paper Photo Copy).

  The calculated glass transition temperature (calculated Tg) of the copolymer used in the paper processing resin emulsion can be calculated by the following formula [1].

Formula [1]
1 / calculated _{Tg = W 1 / Tg (1} ) + W 2 / Tg (2) ······ W n / Tg (n)

In the calculation formula [1], W ₁ , W ₂ ... W _n are the weight fractions of the respective homopolymers of Component 1, Component 2. Tg (1), Tg (2) ... Tg (n) is the glass transition temperature of the homopolymer of component 1, component 2 ... component n (reference values, units are Absolute temperature).

Table 1 shows literature values of glass transition temperatures of typical homopolymers employed in the present invention.
References: J. Brandup, EHImmergut, EAGrulke: Polymer Handbook: JOHNWILEY & SONS, INC

  The paper processing method using the resin emulsion for paper processing obtained by the production method of the present invention is not particularly limited as long as the resin contained in the resin emulsion can adhere to the paper. Or various processing methods, such as the impregnation method by a paper machine, a coating method, a spray method, a size press method, are mentioned.

  The base paper to which the paper processing resin emulsion obtained by the production method of the present invention is applied is not particularly limited. For example, wood pulp paper, paper mainly composed of wood pulp, recycled fiber paper such as rayon, acetate, etc. Examples thereof include synthetic paper such as semi-synthetic paper, polyvinyl alcohol type, polyamide type, polyacrylonitrile type and polyester type, and synthetic paper such as polyethylene and polypropylene.

  The above base paper may be pretreated with various treatment agents such as a sizing agent, pigment, drying enhancer, and wet strength agent, and is not particularly limited.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention more concretely, the scope of the present invention is not limited only to these Examples.
Unless otherwise specified, “%” represents “% by weight” and “part” represents “part by weight”.
The measurement method and evaluation method used in the present invention are as described below.

[Method for measuring viscosity of resin emulsion]
Place the resin emulsion sample in a viscosity measuring tube up to a measurable height, adjust the sample liquid temperature to 25 ° C in a constant temperature water bath set at 25 ° C, and use a BM viscometer (manufactured by Tokyo Keiki Co., Ltd.) or bismetholone viscosity. The viscosity (unit: mPa · s) was measured with a meter (manufactured by Shibaura System Co., Ltd.).

[Measurement method of average particle size of dispersed particles in resin emulsion]
The value (unit: nm) of the average particle diameter (50% median diameter on a volume basis) of the dispersed particles in the resin emulsion was measured with a particle size distribution measuring apparatus (manufactured by Nikkiso Co., Ltd., Microtrac UPA type).

[Method for evaluating strength of test filter paper]
The strength and heat-resistant yellowing of the test filter paper were evaluated by preparing a test filter paper by adhering the compounded liquid to the filter paper according to the following method.
(1) Preparation of test piece The resin emulsion is diluted with water to a solid content of 20%, processed to adhere to filter paper by the mangle impregnation adhesion method, dried under the following conditions, and then used to obtain the test piece. (2.5 cm × 10 cm) was prepared, and the filter paper strength of the test piece was measured under the following dry and wet conditions.
Drying conditions: dried in a hot air dryer at 100 ° C. for 5 minutes, and then dried at 120 ° C. for 1 minute.
(2) Measurement of filter paper strength Strength under dry condition: Immediately after drying, the test piece was measured with a tensile tester at a speed of 300 mm / min and expressed in units (kg / 2.5 cm).
Strength under wet conditions: The test piece was immersed in room temperature water for 30 minutes, then measured with a tensile tester at a speed of 300 mm / min, and expressed in units (kg / 2.5 cm).

[Evaluation method of heat-resistant yellowing of test filter paper]
A test piece was similarly prepared using the test filter paper described above, and the state after drying at 200 ° C. for 10 minutes in a hot air dryer was visually observed and evaluated according to the following evaluation criteria.
○ → No change △ → Change to slightly yellow × → Change to cream

[Method for evaluating size pressability]
Adjust the dilution of the resin emulsion with water to a solid content of 20%, run the size press tester (manufactured by Kumagai Riki Kogyo Co., Ltd.) continuously, warm the diluent to 40 ° C, and maintain a constant flow rate. The time until deposits (scum) appeared on the roller was judged by visual observation and finger touch. Table 1 shows the time (hr) until deposits (scum) appear on the roller.

[Types of polyoxyethylene alkyl ethers that are emulsifiers]
Product name of emulsifier Note 1) Composition Note 2) HLB Note 3) EO addition moles Note 4)
Neugen XL-50 POEDE 11.65
Neugen XL-160 POEDE 16.3 16
Neugen XL-1000 POEDE 20.0 100

Note 1) Neugen XL-50, 160 and 1000 as emulsifiers were all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
Note 2) POEDE; Polyoxyethylene decyl ether Note 3) HLB; Hydrophilic / lipophilic ratio Note 4) EO; Ethylene oxide

[Example 1]
(1) Preparation of Emulsified Solution In a container, 25 parts Neugen XL-1000 [EO addition mole number = 100, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] which is polyoxyethylene alkyl ether as an emulsifier (A) and Neugen XL-160 [ EO addition mole number = 16, made by Daiichi Kogyo Seiyaku Co., Ltd.] 5 parts and 225 parts of deionized water were added and dissolved uniformly, then 430 parts of ethyl acrylate (B), other ethylenically unsaturated monomers As an acid, 55 parts of methyl methacrylate, 5 parts of acrylic acid, 5 parts of itaconic acid and 5 parts of acrylamide-t-butylsulfonic acid (C) as acid monomers were added to carry out emulsification to obtain an emulsion.

(2) Production of Resin Emulsion (EM-1) In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel, Neugen XL-50 [EO addition mole number = 5, Daiichi Kogyo Made by Pharmaceutical Co., Ltd.] 1.5 parts and 430 parts of deionized water were added, and the temperature was raised to 60 ° C. while blowing nitrogen. Under stirring, 4 parts of an aqueous solution of sodium persulfate (active ingredient 2.5%) and 4 parts of an aqueous solution of sodium metabisulfite (active ingredient 2.5%) are added, and 3.2 parts of a 0.15% aqueous ferrous sulfate solution are added. Then, 15.6 parts of the emulsion prepared in the above (1) was charged and polymerized for 30 minutes while maintaining the temperature at 60 ° C. Subsequently, all of the remaining emulsion, 36 parts of an aqueous sodium persulfate solution (active ingredient 2.5%), and 36 parts of an aqueous sodium metabisulfite solution were added for 4 hours while maintaining the reaction temperature at 60 ° C. from separate dropping funnels. The polymerization was carried out dropwise.
After completion of the dropwise addition, the mixture was stirred at 60 ° C. for 2 hours, and then the contents were cooled and adjusted with an aqueous sodium hydroxide solution (active ingredient 10%) so that the pH was 7.0. This was filtered through a 200 mesh wire mesh to obtain a resin emulsion (EM-1) for paper processing of the present invention. The resin emulsion (EM-1) obtained here had a solid content concentration of 45%, a viscosity of 100 mPa · s, an average particle size of dispersed particles of 280 nm, and a calculated Tg = −8 ° C.

[Example 2]
1) Preparation of emulsified solution In a container, 50 parts of Neugen XL-1000 [EO addition mole number = 100, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] which is polyoxyethylene alkyl ether as an emulsifier (A) and Neugen XL-160 [EO Addition mole number = 16, made by Daiichi Kogyo Seiyaku Co., Ltd.] 10 parts and 225 parts of deionized water were added and dissolved uniformly, and then 400 parts of ethyl acrylate (B) and other ethylenically unsaturated monomers 60 parts of methyl methacrylate, 10 parts of acrylic acid as an acid monomer, and acrylate ester SL (manufactured by Mitsubishi Rayon Co., Ltd., 12 carbon atoms) as alkyl (meth) acrylate (D) having an alkyl group having 8 to 15 carbon atoms A mixture of alkyl methacrylates having 13 alkyl groups) 25 parts, having sulfonic acid groups and / or sulfonic acid groups As an ethylenically unsaturated monomer (C), 5 parts of acrylamide-t-butylsulfonic acid was added and emulsified to obtain an emulsion.

(2) Production of Resin Emulsion (EM-2) In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel, Neugen XL-50 [EO addition mole number = 5, Daiichi Kogyo Made by Pharmaceutical Co., Ltd.] and 385 parts deionized water were added, and the temperature was raised to 60 ° C. while blowing nitrogen. Under stirring, 4 parts of an aqueous solution of sodium persulfate (active ingredient 2.5%) and 4 parts of an aqueous solution of sodium metabisulfite (active ingredient 2.5%) are added, and 3.2 parts of a 0.15% aqueous ferrous sulfate solution are added. Then, 15.6 parts of the emulsion prepared in the above (1) was charged and polymerized for 30 minutes while maintaining the temperature at 60 ° C. Subsequently, all of the remaining emulsion, 36 parts of an aqueous sodium persulfate solution (active ingredient 2.5%), and 36 parts of an aqueous sodium metabisulfite solution were added for 4 hours while maintaining the reaction temperature at 60 ° C. from separate dropping funnels. The polymerization was carried out dropwise.
After completion of the dropwise addition, the mixture was stirred at 60 ° C. for 2 hours, and then the contents were cooled and adjusted with an aqueous sodium hydroxide solution (active ingredient 10%) so that the pH was 7.0. This was filtered through a 200 mesh wire mesh to obtain a resin emulsion (EM-2) for paper processing of the present invention. The resin emulsion (EM-2) obtained here had a solid content concentration of 45%, a viscosity of 200 mPa · s, an average particle size of dispersed particles of 280 nm, and a calculated Tg = −10 ° C.

Example 3
(1) Preparation of Emulsified Solution In a container, 25 parts Neugen XL-1000 [EO addition mole number = 100, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] which is polyoxyethylene alkyl ether as an emulsifier (A) and Neugen XL-160 [ EO addition mole number = 16, made by Daiichi Kogyo Seiyaku Co., Ltd.] 5 parts and 225 parts deionized water were added and dissolved uniformly, then 275 parts ethyl acrylate (B), 135 parts butyl acrylate (E), etc. Acrylate SL (Mitsubishi Rayon) as an alkyl (meth) acrylate (D) having 50 parts of methyl methacrylate as an ethylenically unsaturated monomer, 10 parts of acrylic acid as an acid monomer, and an alkyl group having 8 to 15 carbon atoms Co., Ltd., a mixture of alkyl methacrylate having an alkyl group having 12 and 13 carbon atoms) (D) 25 parts, Emulsification was performed by adding 5 parts of acrylamide-t-butylsulfonic acid (C) to obtain an emulsion.

(2) Production of Resin Emulsion (EM-3) In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel, Neugen XL-50 [EO addition mole number = 5, Daiichi Kogyo Made by Pharmaceutical Co., Ltd.] and 355 parts of deionized water were added, and the temperature was raised to 60 ° C. while blowing nitrogen. Under stirring, 4 parts of an aqueous solution of sodium persulfate (active ingredient 2.5%) and 4 parts of an aqueous solution of sodium metabisulfite (active ingredient 2.5%) are added, and 3.2 parts of a 0.15% aqueous ferrous sulfate solution are added. Then, 15.6 parts of the emulsion prepared in the above (1) was charged and polymerized for 30 minutes while maintaining the temperature at 60 ° C. Subsequently, all of the remaining emulsion, 36 parts of an aqueous sodium persulfate solution (active ingredient 2.5%), and 36 parts of an aqueous sodium metabisulfite solution were added for 4 hours while maintaining the reaction temperature at 60 ° C. from separate dropping funnels. The polymerization was carried out dropwise.
After completion of the dropwise addition, the mixture was stirred at 60 ° C. for 2 hours, and then the contents were cooled and adjusted with an aqueous sodium hydroxide solution (active ingredient 10%) so that the pH was 7.0. This was filtered through a 200 mesh wire mesh to obtain a resin emulsion (EM-3) for paper processing of the present invention. The resin emulsion (EM-3) obtained here had a solid content concentration of 45%, a viscosity of 300 mPa · s, an average particle size of dispersed particles of 280 nm, and a calculated Tg = −19 ° C.

[Comparative Example 1]
1) Preparation of Emulsified Solution In a container, 25 parts Neugen XL-1000 [EO addition mole number = 100, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] which is polyoxyethylene alkyl ether as an emulsifier (A) and Neugen XL-160 [EO Addition mole number = 16, made by Daiichi Kogyo Seiyaku Co., Ltd.] 5 parts and 225 parts of deionized water were added and dissolved uniformly, then 430 parts of ethyl acrylate (B) and other ethylenically unsaturated monomers And 55 parts of methyl methacrylate and 5 parts of acrylic acid and 5 parts of itaconic acid as acid monomers were added to carry out emulsification to obtain an emulsion.

(2) Production of Resin Emulsion (EM-4) In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel, Neugen XL-50 [EO addition mole number = 5, Daiichi Kogyo Made by Pharmaceutical Co., Ltd.] 1.5 parts and 355 parts of deionized water were added, and the temperature was raised to 60 ° C. while blowing nitrogen. Under stirring, 4 parts of an aqueous solution of sodium persulfate (active ingredient 2.5%) and 4 parts of an aqueous solution of sodium metabisulfite (active ingredient 2.5%) are added, and 3.2 parts of a 0.15% aqueous ferrous sulfate solution are added. Then, 15.6 parts of the emulsion prepared in the above (1) was charged and polymerized for 30 minutes while maintaining the temperature at 60 ° C. Subsequently, all of the remaining emulsion, 36 parts of an aqueous sodium persulfate solution (active ingredient 2.5%), and 36 parts of an aqueous sodium metabisulfite solution were added for 4 hours while maintaining the reaction temperature at 60 ° C. from separate dropping funnels. The polymerization was carried out dropwise.
After completion of the dropwise addition, the mixture was stirred at 60 ° C. for 2 hours, and then the contents were cooled and adjusted with an aqueous sodium hydroxide solution (active ingredient 10%) so that the pH was 7.0. This was filtered through a 200 mesh wire mesh to obtain a resin emulsion (EM-4). The resin emulsion (EM-4) obtained here had a solid content concentration of 45%, a viscosity of 150 mPa · s, an average particle size of dispersed particles of 250 nm, and a calculated Tg = −8 ° C.

[Comparative Example 2]
(1) Preparation of emulsified liquid In a container, as an emulsifier (A), 1.725 parts of a 58.0% solution of ammonium polyoxyethylene nonylphenyl ether sulfate, 14.3 parts of a 70% solution of polyoxyethylene nonylphenyl ether, polyoxyethylene 5 parts of ethylene alkyl beta methyl stidenyl ether (ethylene glycol addition mole number about 50) and 187.5 parts of deionized water were added and uniformly dissolved, then 271.5 parts of ethyl acrylate (B), butyl acrylate ( E) 193.5 parts, 25 parts of acrylonitrile, and 10 parts of itaconic acid as an acid monomer were added and emulsified to obtain an emulsion.

(2) Production of resin emulsion (EM-5) In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 229 parts of deionized water was added and heated to 60 ° C. while blowing nitrogen. The temperature rose. Under stirring, 4 parts of sodium persulfate aqueous solution (active ingredient 2.5%), 4 parts of sodium metabisulfite aqueous solution (active ingredient 2.5%) and 3.2 parts of 0.15% ferrous sulfate aqueous solution were added. Then, 15.6 parts of the emulsion was charged and polymerized for 0.5 hours while maintaining 60 ° C. Subsequently, all of the remaining emulsion and 36 parts of sodium persulfate aqueous solution (active ingredient 2.5%) and sodium metabisulfite aqueous solution 36 parts were added while maintaining the reaction temperature at 60 ° C. using a separate dropping funnel. It dropped and polymerized over time.
After completion of the dropwise addition, the mixture was stirred at 60 ° C. for 2 hours, and then the contents were cooled and adjusted with an aqueous sodium hydroxide solution (active ingredient 10%) so that the pH was 7.0. This was filtered with a 200 mesh wire mesh to obtain a resin emulsion (EM-5). The resin emulsion (EM-5) obtained here had a solid content concentration of 55%, a viscosity of 800 mPa · s, an average particle size of dispersed particles of 200 nm, and a calculated Tg = −25 ° C.

The method for producing a resin emulsion for paper processing according to the present invention is excellent in size pressability at the time of processing, so that no deposit is generated when manufacturing a processed paper, there is no decrease in production efficiency or poor quality of the processed paper, and , Paper processing resin emulsions that impart excellent properties such as strength and heat-resistant yellowing to processed paper can be provided, and processed papers obtained using such paper processing resin emulsions include, for example, copy paper, foam paper, report paper It can be used for a wide range of applications such as memo paper, measurement recording paper, and slips.

Claims (5)

In the presence of the emulsifier (A), an ethylenically unsaturated monomer containing methyl acrylate and / or ethyl acrylate (B) and an ethylenically unsaturated monomer (C) having a sulfonic acid group and / or a sulfonic acid group as essential components. A method for producing a resin emulsion for paper processing , comprising emulsion polymerization of saturated monomers, wherein the content of methyl acrylate and / or ethyl acrylate (B) in the ethylenically unsaturated monomers 30 to 70% by weight, the content of the ethylenically unsaturated monomer (C) having a sulfonic acid group and / or a sulfonic acid group is 0.1 to 5% by weight, and an alkyl group having 8 to 15 carbon atoms. Paper having a content of alkyl (meth) acrylate (D) of 1 to 10% by weight and a content of butyl (meth) acrylate (E) of 9 to 60% by weight Method of manufacturing engineering for the resin emulsion. A sulfonic acid group and / or ethylenically unsaturated monomer having a sulfonic acid salt (C) The production method of claim 1, wherein the paper coating resin emulsion acrylamide -t- butyl sulfonic acid. The method for producing a resin emulsion for paper processing according to claim 1 , wherein the emulsifier (A) is polyoxyethylene alkyl ether. The method for producing a resin emulsion for paper processing according to any one of claims 1 to 3 , wherein the emulsifier (A) is a polyoxyethylene alkyl ether having an average of 50 to 150 oxyethylene units in one molecule. The paper processing according to any one of claims 1 to 4 , wherein the emulsifier (A) is present in a range of 3 to 10 parts by weight with respect to 100 parts by weight of the total amount of the ethylenically unsaturated monomers. For producing resin emulsions.