JPH05171598A - Composition for paper coating and coated paper using the same - Google Patents

Abstract

PURPOSE:To provide the subject composition excellent in the redispersibility in water and bond strength, containing a copolymer latex prepared by incorporating specific olefin polymer ingredients with an anionic reactive surfactant containing in the molecule allyl group. CONSTITUTION:The objective composition containing a copolymer latex comprising (A) a copolymer from a total 100 pts.wt. of (1) 20-60wt.% of aliphatic conjugated diolefin monomer, (2) 1-10wt.% of mono-olefin-based unsaturated carboxylic acid monomer, (3) 10-70wt.% of mono-olefin aromatic monomer, and (4) 0-70wt.% of another kind of copolymerizable monomer and (B) 0.1-10 pts.wt. of an anionic reactive surfactant containing in the molecule allyl group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper coating composition capable of obtaining a coated paper having excellent coating suitability and high surface strength.

[0002]

2. Description of the Related Art In recent years, in the paper manufacturing industry, the demand for coated paper has increased remarkably, and the demand for quality has also increased. In particular, there is a strong demand for quality improvement in dry strength and wet strength, and a paper coating composition having excellent adhesive strength has been required. In addition to the improvement of the quality of coated paper, of course, high-speed coating has been used to improve productivity. Since the speed of many coating machines is operating at the limit at which they can be operated, it often becomes a problem that troubles such as stains on the machines occur during coating work. The most likely problem with machine stains during high-speed coating is that in a double-sided coating machine, one side is first coated and then the other side is coated. It is a part. The backup roll of the second coater hits the coating surface immediately after being first coated and immediately after passing through the drying zone while directly contacting, so that a part of the coating layer component is dropped off and adheres to the roll surface as dirt. easy. In addition, a flow clean doctor is often installed on the backup roll for the purpose of cleaning the adhered material with water, but even in this case, the adhered coating layer composition does not disperse in water. , Remains as dirt. When such dirt adheres and accumulates, the physical properties of the coated paper obtained due to non-uniformity of coating, such as deterioration of surface properties and printability, or when the accumulation is excessive, the operation should be performed. You will have to stop and remove the deposits. In order to prevent such back-up roll stains, the paper coating composition should be a coating composition with little adhesion to the roll, and even if it adheres,
It must be of a nature that makes it easy to wash with flow clean wash water. However, a coating composition of a type in which the coated paper has a high adhesive strength usually has a strong adhesiveness to a roll, and in many cases has poor dispersibility in washing water, resulting in The result is that the backup roll easily becomes dirty. As an example of improving the stain resistance of the backup roll, JP-A-63-8439 and JP-A-63-12647 disclose methods for improving the stickiness resistance of latex. However, these cannot be said to be sufficient stain prevention methods, and they do not positively improve the redispersibility of the paper coating composition in water to facilitate cleaning. From the above,
There is a strong need for a paper coating composition for use in a flow clean device, which has a high redispersibility in water and a high adhesive strength after coating.

[0003]

DISCLOSURE OF THE INVENTION As a result of intensive research aimed at solving this problem, the present inventors have found that an aliphatic conjugated diolefin system using an anionic reactive surfactant containing an allyl group in the molecule is used. It has been found that a paper coating composition using a copolymer latex as an adhesive has excellent redispersibility in water and excellent adhesive strength of the coated paper, and thus completed the present invention.

[0004]

Means for Solving the Problems That is, the present invention is as follows. In a paper coating composition containing a pigment and an adhesive as main components, the constituent polymer component of the adhesive has the following (A)
~ (D), which contains a copolymer latex in which 0.1 to 10 parts by weight of an anionic reactive surfactant containing an allyl group in the molecule is used with respect to 100 parts by weight of the constituent polymer component. And a coated paper obtained by coating the composition. (A) Aliphatic conjugated diolefin monomer 20 to 60% by weight (B) Monoolefin unsaturated carboxylic acid monomer 1 to 10% by weight (C) Monoolefin aromatic monomer 10 to 70% by weight % (D) Other copolymerizable monomer 0 to 70% by weight

The present invention will be described in detail below. The copolymer latex used as the adhesive of the paper coating composition in the present invention is, in a broad sense, SBR latex, MBR latex, SM produced by emulsion copolymerization.
It is called BR latex or the like. Among the monomers constituting the copolymer latex produced by the present invention, the aliphatic conjugated diolefin-based monomer is, for example, 1,3-butadiene, 2-methyl-1,3-butadiene, 2- Chloro-1,3-butadiene and the like can be mentioned, and these can be used alone or in combination of two or more kinds. These monomers give the copolymer an appropriate elasticity, and the amount used is
20 to 60% by weight is suitable for the constituent polymer. Two
If it is less than 0% by weight, the glass transition temperature of the copolymer latex will be high, and the surface strength of the obtained coated paper will be lowered.
When it exceeds 0% by weight, the redispersibility in water of the paper coating composition using the same decreases. It is preferably 25 to 50% by weight. Examples of the monoolefinic unsaturated carboxylic acid monomer used in the present invention include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid and maleic acid, and further itaconic acid monoethyl ester. , Monoalkyl esters of unsaturated dicarboxylic acids such as fumaric acid monobutyl ester and maleic acid monopropyl ester, 2-sulfoethyl acrylate, styrene sulfonic acid, and unsaturated sulfonic acids such as acrylamide propane sulfonic acid. They can be used alone or in combination of two or more.
The amount used is 1 with respect to 100 parts by weight of the constituent polymer components.
-10 wt% is suitable. If it is less than 1% by weight, the polymerization stability of the copolymer latex is poor, and if it exceeds 10% by weight, the viscosity of the copolymer becomes high and it becomes difficult to use it. It is preferably 2 to 8% by weight.

Examples of the monoolefin aromatic monomer used in the present invention include styrene, α-methylstyrene, vinyltoluene and the like, and these can be used alone or in combination of two or more kinds. The amount used is appropriately 10 to 70% of the constituent polymer. 10%
If it is less than 100%, the glass transition temperature of the copolymer latex becomes low, the redispersibility in water of the paper coating composition using the copolymer latex is poor, and if it exceeds 70%, the surface strength of the obtained coated paper becomes low. descend. It is preferably 20 to 60% by weight.
Other copolymerizable monomers include, for example, acrylic acid esters such as methyl acrylate and ethyl acrylate, methacrylic acid esters such as methyl methacrylate, and olefinic unsaturated compounds such as diethyl fumarate and dimethyl itaconate. Carboxylic acid alkyl ester compounds, vinyl cyanide compounds such as acrylonitrile, α-chloroacrylonitrile and methacrylonitrile, and olefin unsaturated carboxylic acid amides such as acrylamide, methacrylamide and N-methylol acrylamide, and their N-substituted compounds , 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate and other functional alkyl ester compounds and vinyl acetate and other vinyl esters. These other monomers impart appropriate hardness to the copolymer and can be used alone or in combination of two or more kinds. The amount used is 0 to the constituent polymer.
70% by weight is suitable. If it exceeds 70% by weight,
The surface strength of the obtained coated paper decreases. Preferably 20
˜50 parts by weight. Examples of the allyl group-containing anionic reactive surfactant used in the present invention include those represented by the following general formulas (1) to (6).

[0007]

[Chemical 7]

[0008]

[Chemical 8] [In the formula (1) or (2), R ₁ is hydrogen or a methyl group, and
₂ is an organic group containing a hydrocarbon group or a hydrocarbon having a substituent or an oxyalkylene group, A is an alkylene group having 2 to 4 carbon atoms or a substituted alkylene group, n is 0 or a positive number, and M is Alkali or alkaline earth metal,
A sulfosuccinate compound such as NH ₄ , an organic amine base, or an organic quaternary ammonium base. ]

[0009]

[Chemical 9]

[0010]

[Chemical 10] [In the formula (3) or the formula (4), R ₁ represents a hydrocarbon group which may have a substituent, a phenyl group, an amino group or a carboxylic acid residue, and R ₂ represents a hydrogen atom or a methyl group, A is an alkylene group having 2 to 4 carbon atoms, n is a positive number from 0 to 100, and M is a sulfosuccinate compound showing a monovalent or divalent cation. ]

[0011]

[Chemical 11] (In the formula, R ₁ is an alkyl group, alkenyl group, or aralkyl group having 4 to 18 carbon atoms, R ₂ is hydrogen or an alkyl group, alkenyl group, or aralkyl group having 4 to 18 carbon atoms, and A is 2 to 2 carbon atoms. 4 is an alkylene group or a substituted alkylene group, n is an integer of 2 to 200, and M is a compound which is an alkali metal atom, NH ₄ , or an alkanolamine residue.)

[0012]

[Chemical 12] (In the formula, A is an alkylene group having 2 to 4 carbon atoms, a substituted alkylene group, or an alkyleneoxy group, and n is 1
~ 100 represents a positive number, M is an alkali metal atom NH ₄
Is a compound that represents )

These anionic reactive surfactants are known ones, for example, JP-A-62-221431.
JP-A-63-23725, JP-A-2-47107
, Etc., Aqualon HS-10, RN
-20 (Daiichi Kogyo Seiyaku Co., Ltd.), Latemur S-180,
S-180S (Kao Corporation), Eleminor JS-2,
RS-30 (Sanyo Chemical Co., Ltd.), ANTOX-MS
-60, MS-2N (Nippon Emulsifier Co., Ltd.) and the like are commercially available. These anionic reactive surfactants are added to the emulsion copolymerization system in an amount of 0.1 to 100 parts by weight of the constituent polymer.
It is suitable to use in the range of 10 to 10 parts by weight, preferably 0.2 to 5 parts by weight. In particular, 0.1 to polymer
The reason for limiting the amount to 10 parts by weight is 10 with respect to the constituent polymer.
When the amount is more than the weight part, the surface strength of the coated paper obtained by this composition for paper coating, particularly the wet strength is lowered. On the other hand, if the amount is less than 0.1 part by weight, the effect of improving the redispersibility in water of the paper coating composition of the present invention is small. The method for producing the copolymer latex of the present invention is not particularly limited as long as it is a known emulsion polymerization method. During emulsion polymerization,
Other emulsifiers may not be used in combination, but examples of emulsifiers that can be used in combination include higher alcohol sulfates, anionic surfactants such as alkylbenzene sulfonates and aliphatic sulfonates, and alkyl ester type polyethylene glycols. , Alkylphenyl ether type, alkyl ether type nonionic surfactants, and betaine type amphoteric surfactants, and reactive surfactants other than anionic reactive surfactants, that is, nonionic and cationic surfactants. The reactive surfactants can be used alone or in combination of two or more, and can be used together with the anionic reactive surfactant. As the polymerization initiator, for example, a water-soluble initiator such as potassium persulfate, ammonium persulfate, or sodium persulfate, an oil-soluble initiator such as benzoyl peroxide or azobisisobutyronitrile, or a redox initiator can be used. .. As the chain transfer agent, for example, butyl mercaptan, octyl mercaptan, n-dodecyl mercaptan, mercaptans such as t-dodecyl mercaptan,
There are sulfides such as tetraethyl thiuram sulfide and halogenated alkyls such as methylene chloride, chloroform and bromoform, and these may be used alone or in combination of two or more kinds. When pH is adjusted with an alkali metal compound after polymerization of the above-mentioned monomers, examples of the neutralizing agent used include sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, and disodium phosphate. , Potassium triphosphate, dipotassium phosphate and the like, and these can be used alone or in combination of two or more kinds. The latex particles are prepared as described above, and the particle diameter of the latex added as the adhesive in the present invention is 50 to 1
70 nm, preferably 90-130 nm.
It is difficult to prepare a latex having a particle size of less than 50 nm, and one having a particle size of more than 170 nm cannot give the water resistance required for the coated paper obtained. The particle size in the present invention is a value measured by a COULTER N4SD particle size measuring instrument manufactured by Nikkaki.

In addition to the copolymer latex and the pigment, the composition for coated paper of the present invention may optionally contain various additives such as a dispersant, a water resistant agent, a viscosity modifier, and an antifoaming agent. Examples of the pigment that can be used in the present invention include inorganic pigments such as clay, calcium carbonate, aluminum hydroxide, titanium white, satin white, and talc, and organic pigments such as polystyrene and phenol resin, and among them, kaolinite. Clay is preferred. Further, as the binder, in addition to the copolymer latex of the present invention, a water-soluble polymer such as starch, casein, or polyvinyl alcohol, an emulsion such as polyvinyl acetate or an acrylate copolymer may be used in combination, if necessary. Can be done. The copolymer latex of the present invention is usually used in the range of 5 to 30 parts by weight based on the pigment. The thus obtained paper coating composition is coated in the same manner as in general coated paper production, for example, by a coating device such as an air knife coater, a blade coater, a roll coater and a bar coater. The effect of the present invention is remarkable in double-sided coating with a blade coater at a machine speed of 800 m / min or more, and the solid content of the paper coating composition at this time is usually 40 to 70% by weight. Further, as the coated paper, a high-quality paper, a medium weight paper, a paperboard having a basis weight of 40 to 300 g / m ² or a coated paper in which a composition for paper coating is previously coated on one side or both sides thereof as a base paper is used. Used. Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following examples, parts and% used are based on weight unless otherwise specified.

[0015]

【Example】

(Production of Latex A) Production Example 1 150 parts of deionized water, 0.3 part of Latemur S-180, 0.2 part of sodium lauryl sulfate, 0.6 part of potassium persulfate were placed in an autoclave equipped with a stirrer and purged with nitrogen. , 0.6 part of normaldodecyl mercaptan, and 40 parts of butadiene as a monomer, 25 parts of styrene, 20 parts of methyl methacrylate, 10 parts of acrylonitrile, 1 part of itaconic acid.
Parts, 2 parts of acrylic acid, and 2 parts of hydroxyethyl methacrylate were charged in total for 100 parts to obtain a copolymer latex having a polymerization rate of 98% at 70 ° C. for 10 hours. Then 25
The pH is adjusted to 8.0 with an aqueous solution of caustic soda, and steam stripping is performed to remove unreacted monomers, and deionized water is added to make the solid content concentration 46.0%. I got A. Production Examples 2 to 5 Polymer latex B was produced under the same conditions as in Production Example 1, except that the raw materials in the proportions shown in Table 1 were used.
C, D and E were obtained. Production Comparative Examples 6 to 9 Production Comparative Examples are latex production examples for the paper coating composition of the present invention and for comparison. Polymer latexes F, G, H and I were obtained under the same conditions as in Production Example 1 except that the raw materials shown in Table 1 were used.

(Evaluation of Coating) Examples 1 to 5 and Comparative Examples 1 to 4 (Preparation of Coating Material) Copolymer Latex A to I prepared above
Was used to prepare a coating composition according to the following formulation to obtain a paint. 《Compound formulation》 No. 1 Kaolin clay 70 parts by weight Heavy carbon calcium 30 parts by weight Dispersant 0.3 parts by weight NaOH 0.1 parts by weight Oxidized starch 4 parts by weight Copolymer latex 12 parts by weight ────── ——————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————−— (Preparation of coated paper for test) The above coating composition is manually coated on a fine paper with an applicator bar having an appropriate clearance so that the dry coating amount on one side is 15 g / m ^2. Then, the coated paper was immediately dried with a box type hot air dryer at 120 ° C. for 20 seconds. The coated paper obtained has an additional 20
Seasoning is performed overnight under the conditions of ℃ relative humidity 65%, and then super calendering is performed twice under the conditions of 60 ℃ linear pressure and 100 kg / cm, and the coated paper obtained by this is used for the printing strength test. did. The obtained coated paper was evaluated according to the test methods shown below, and the results are shown in Table 2.

[0017]

[Table 1]

[0018]

[Table 2] (1) Dry pick strength test Using a RI printing aptitude tester (manufactured by Akira Mfg. Co., Ltd.), the tacking ink (Toyo Ink SMX Tack 15) was visually determined for the paper peeling state, and the 10-point method (10 points Excellent and 1 point were evaluated as poor). (2) Wet strength test With an RI printability tester, dampening water was applied using a molton roll to give tack ink (Toyo Ink SMX Tuck 10).
The state of peeling of the paper was visually determined by the printing, and evaluated by a 10-point method (10 points excellent, 1 point poor). (3) Gloss of white paper The coated paper after the super calender treatment was measured with a Murakami type gloss meter at a reflectance of 75 ° -75 °. (4) Print Gloss Using an RI printability tester, after printing with a printing ink (Toyo Ink New Bright Indigo), it was measured with a Murakami type gloss meter at a reflectance of 75 ° to 75 °. (5) Inking of ink When printing with a printing ink (Toyo Ink New Bright Indigo) using an RI printability tester, water is placed between the metal roll and the rubber roll so that the ink and water intervene at the same time. Printing was performed under the conditions, and the ink density was measured with a Macbeth densitometer. (6) Absorbing swimsuit meat Using a RI printability tester, water was applied to the test piece with a molton roll, and after printing with a printing ink (Toyo Ink New Bright Indigo) under the conditions that no paper peeling occurred, Macbeth density The ink density was measured with a meter. (7) Redispersibility of paper coating composition in water A certain amount of a paper coating composition is applied to a urethane sheet, air-dried, and then re-dispersed in water to remove the coating layer. Visually judge the situation, and use the ○ × method (Excellent to inferior ◎, ○, △,
Evaluation was made in the order of x).

[0019]

EFFECTS OF THE INVENTION The values in Table 2 show that the coated papers obtained from the coated paper compositions of the examples within the limits of the present invention have excellent adhesive strength and redispersibility. It is obvious that the present invention is a novel and useful composition for coated paper.

Front page continuation (72) Inventor Akio Tanaka 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd.

Claims (7)

[Claims] 1. In a paper coating composition containing a pigment and an adhesive as main components, the constituent polymer components of the adhesive are the following (A) to (D), and allyl is included in the molecule. A group-containing anionic reactive surfactant is used as a constituent polymer component 100.
A paper coating composition comprising 0.1 to 10 parts by weight of a copolymer latex based on parts by weight. (A) Aliphatic conjugated diolefin monomer 20 to 60% by weight (B) Monoolefin unsaturated carboxylic acid monomer 1 to 10% by weight (C) Monoolefin aromatic monomer 10 to 70% by weight % (D) Other copolymerizable monomer 0 to 70% by weight 2. The aliphatic conjugated diolefin-based monomer is 1,
3-butadiene, 2-methyl-1,3-butadiene or 2-
The paper coating composition according to claim 1, which is a single chloro-1,3-butadiene or a combination of two or more thereof. 3. The monoolefin unsaturated carboxylic acid monomer is an unsaturated carboxylic acid, a monoalkyl ester of an unsaturated dicarboxylic acid, or an unsaturated sulfonic acid, either alone or in combination of two or more. Composition for paper coating of. 4. The composition for paper coating according to claim 1, wherein the monoolefin aromatic monomer is styrene, α-methylstyrene, or vinyltoluene alone or in combination of two or more. 5. The other copolymerizable monomer is acrylic acid ester, methacrylic acid ester, olefinic unsaturated carboxylic acid alkyl ester compound, vinyl cyanide compound, olefinic unsaturated carboxylic acid. The paper coating composition according to claim 1, which is an amide or its N-substituted compound, a functional alkyl ester compound or a vinyl ester, either alone or in combination of two or more. 6. The anionic reactive surfactant containing an allyl group in the molecule is a compound represented by the following general formulas (1) to (6) alone or in combination of two or more. The composition for paper coating according to claim 1. [Chemical 1] [Chemical 2] [In the formula (1) or (2), R ₁ is hydrogen or a methyl group, and
₂ is a hydrocarbon group or an organic group containing a hydrocarbon having a substituent or an oxyalkylene group, A is an alkylene group having 2 to 4 carbon atoms or a substituted alkylene group, n is 0 or a positive number, M is an alkali Or alkaline earth metal, N
A sulfosuccinate-based compound such as H ₄ , an organic amine base, or an organic quaternary ammonium base. ] [Chemical 3] [Chemical 4] [In the formula (3) or the formula (4), R ₁ represents a hydrocarbon group which may have a substituent, a phenyl group, an amino group or a carboxylic acid residue, and R ₂ represents a hydrogen atom or a methyl group, A is an alkylene group having 2 to 4 carbon atoms, n is a positive number from 0 to 100, and M is a sulfosuccinate compound showing a monovalent or divalent cation. ] [Chemical 5] (In the formula, R ₁ is an alkyl group, alkenyl group, or aralkyl group having 4 to 18 carbon atoms, R ₂ is hydrogen or an alkyl group, alkenyl group, or aralkyl group having 4 to 18 carbon atoms, and A is 2 to 2 carbon atoms. 4 is an alkylene group or a substituted alkylene group, n is an integer of 2 to 200, and M is an alkali metal atom, NH ₄ , or an alkanolamine residue. (In the formula, A is an alkylene group having 2 to 4 carbon atoms, or a substituted alkylene group or an alkyleneoxy group, and n is 1 to 100.
Represents a positive number and M is a compound representing an alkali metal atom, NH ₄ . ) 7. A coated paper obtained by coating the paper coating composition according to claim 1.