JP2000273794A - Humectant for paper coating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a humectant for paper coating agents, comprising a specific copolymer and capable of providing a paper coating agent exhibiting proper thickening property, fluidity under high shear, water holding capacity, etc., by applying the copolymer to an aqueous paper coating agent comprising pigment, a binder, a dispersing agent, etc. SOLUTION: This humectant for paper coating agent is obtained subjecting at least one kind of monomer selected from a group comprising (meth)acrylic ester, a vinyl carboxylate and styrene, preferably a monomer of formula I (R1 is H or CH3; R2 is a 1-22C alkyl or the like) or formula II (R3 is a 1-17C alkyl or the like) to emulsion copolymerization with a monomer containing at least one kind of group selected from a group comprising carboxyl group, hydroxyl group, amide group and amino group, preferably a monomer represented by formula III [R1 is H or CH3; M is H, an alkali (earth) metal or the like], formula IV [R5 is a 2-30C alkylene; (n) is 1-100] or the like and compounds represented by formula V [R11 is H or a 1-22C (un)saturated hydrocarbon; R12 is an 8-40C long-chain (un)saturated hydrocarbon].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-retaining agent for a paper coating composition, and more particularly, to a paper coating composition having an appropriate viscosity, fluidity under a high shear rate, water retention, and coating suitability. The present invention also relates to a water retention agent for a paper coating agent, which imparts excellent performance to printability of coated paper.

[0002]

BACKGROUND OF THE INVENTION Paper coating composition for producing coated paper (hereinafter referred to as "coating liquid")
Is an aqueous dispersion mixture mainly composed of a pigment, a binder, water, and various additives. As the pigment, kaolin, calcined clay, calcium carbonate, and the like, and as the binder (or adhesive), SBR latex, MB
A synthetic rubber-based aqueous dispersion such as an R-based latex is used,
Further, natural water-soluble polymers such as starch, casein, and soy protein are used.

[0003] In recent years, however, there has been a demand for a higher concentration (lower water content) of a coating liquid in order to reduce costs in consideration of the enormous energy consumption when drying a coating layer in production. In addition, the demand for coated paper has increased drastically, and the speed of the process has been demanded.In the coating process, the speed has been increased, and particularly the good fluidity of the coating liquid accompanying the speeding of the coater, that is, under a high shear rate Fluidity of the coating liquid is strongly required.
On the other hand, under a low shear rate, it is necessary to give an appropriate viscosity, and high water retention has been required. If the water retention is insufficient, the water in the coating liquid will rapidly penetrate and migrate into the paper during coating, causing an increase in the concentration of the coating liquid on the coating surface, resulting in defects in the quality of the coated paper. Or cause operational problems.

For the purpose of improving the water retention, carboxymethylcellulose, methylcellulose, modified starch, sodium alginate, polyvinyl alcohol, polystyrene / maleic acid and the like have been used as water retention agents.

[0005] However, although they are very excellent in water retention, they have problems such as poor fluidity under high shear rate, low fluidity at high concentration, poor coating suitability and poor printability. Had many disadvantages.

Improvements have been made to butadiene-based latexes as binders (adhesives). For example, attempts have been made to improve various physical properties by introducing about 0.5 to 10% of a carboxyl group into a butadiene-based latex. . However, although these are excellent in printability and the like due to structural restrictions and the like, it was impossible at all to impart performance other than printability, particularly water retention.

Therefore, many water retention agents have been proposed for the purpose of solving the drawbacks of the conventional water retention agents. For example, as a water-soluble polymer, an acrylamide-based polymer is disclosed in
JP-A-5-222696, JP-A-8-17029
No. 8 and the like, as styrene sulfonic acid-based compounds,
No. 89196 and the like, and examples of polyvinyl alcohol-based emulsions include JP-A-3-124899, and examples of carboxylic acid-based alkali-soluble emulsions include JP-A-52-118015 and JP-A-56-101995.
No., JP-A-61-43607, JP-B-62-8560.
No., JP-B-4-9238, JP-A-8-188987
JP-A-9-268496, JP-A-10-2377
No. 97 and the like.

However, these conventional water retention agents have insufficient water retention, and if the amount added is increased to improve the water retention, the viscosity becomes high, especially at high shearing speeds, making coating difficult. Therefore, there is a disadvantage that high concentration and high speed cannot be achieved. Furthermore, these conventional water retention agents cause defects in the quality of coated paper such as streaks, scratches and bleeding and troubles in operation, and, in terms of printability of the coated paper, white gloss, print gloss, dryness and gloss. It was far from satisfying wet topic surface strength, blister resistance, smoothness, ink acceptability, halftone dot reproducibility, and the like. The market has long been eager to develop such excellent water retention agents.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a paper coating composition with a suitable thickening property at a low shear rate and a good viscosity at a high shear rate. Giving excellent fluidity, providing excellent water retention and excellent coating suitability, and reducing the drying energy by increasing the concentration.
It is an object of the present invention to provide a water-retaining agent for a paper coating agent capable of improving the quality of coated paper such as the improvement of productivity by improving the coating speed and the improvement of printability.

[0010]

The water-retaining agent for a paper coating composition of the present invention is selected from the group consisting of (meth) acrylate monomers, vinyl carboxylate monomers and styrene monomers. At least one selected monomer (A)
And at least one monomer (B) selected from the group consisting of a carboxyl group-containing monomer, a hydroxyl group-containing monomer, an amide group-containing monomer, and an amino group-containing monomer; A long chain saturated hydrocarbon having 8 or more carbon atoms and / or a long chain having 8 or more carbon atoms, which has a propenyl group and a polyoxyethylene group, and is located at a terminal opposite to the propenyl group side of the chain where the polyoxyethylene group is present; It comprises a copolymer obtained by copolymerizing at least one kind of monomer (C) selected from compounds having a saturated hydrocarbon group.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Main items relating to the configuration of the present invention will be described in detail below item by item. (1) Monomer (A) Among the monomers constituting the copolymer (water retention agent for paper coating agent ) in the present invention, the monomer (A) is a (meth) acrylate monomer , Vinyl carboxylate monomers, and styrene monomers. These monomers (A)
Are used alone or in combination of two or more.

Among the above monomers (A), preferred monomers are those represented by the following formulas (A-1) to (A-3).

Embedded image (Wherein, R ¹ represents hydrogen or a methyl group, and R ² has 1 to 1 carbon atoms.
22 alkyl groups, alkenyl groups, cycloalkyl groups,
A cycloalkenyl group, an aryl group, an aralkyl group, or an aralkenyl group, R ³ represents an alkyl group having 1 to 17 carbon atoms, a chloromethyl group, or a phenyl group, and R ⁴ represents hydrogen or an alkyl group having 1 to 4 carbon atoms. Show. ).

The monomers represented by the general formulas (A-1) to (A-3) may be used alone or in combination of two or more. Among these, the monomer represented by the general formula (A-1) is particularly preferred.

Specific examples of the monomer (A) are shown below. Examples of the (meth) acrylic ester-based monomer include, as examples of the monomer represented by the general formula (A-1), methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meta)
Acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, tetradecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, icosyl (= eicosyl)
(Meth) acrylate, henycosyl (= heneicosyl) (meth) acrylate, docosyl (meth) acrylate, octadecenyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth)
Acrylate, benzyl (meth) acrylate and the like can be mentioned, and preferred are ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate and butyl methacrylate, and particularly preferred is ethyl acrylate.

Examples of the vinyl carboxylate monomer include those represented by the above general formula (A-2), such as vinyl acetate, vinyl propionate, vinyl butyrate (vinyl butanoate), Vinyl valerate (vinyl pentanoate), vinyl pivalate (vinyl 2,2-dimethylpropionate),
Vinyl caproate (vinyl hexanoate), vinyl octanoate, vinyl nonanoate, vinyl decanoate, vinyl undecanoate, vinyl laurate, vinyl tridecanoate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl monochloroacetate, benzoate And vinyl acetate and the like, preferably vinyl acetate and vinyl propionate.

As examples of the styrene-based monomer, examples of the monomer represented by the general formula (A-3) include styrene,
α-methylstyrene, o-, m-, p-methylstyrene, o-, m-, p-ethylstyrene, o-, m-, p
-Isopropylstyrene, o-, m-, p-tert-
Butyl styrene and the like are preferred, and styrene is preferred.

The most preferred monomer among the monomers (A) is ethyl acrylate.

The amount of the monomer (A) constituting the copolymer is 25 to 75% by weight (hereinafter, unless otherwise specified,%
Indicates% by weight. ), Preferably 40-70%.
When the amount of (A) is less than 25%, the viscosity of the coating liquid becomes too high, and when it exceeds 75%, sufficient viscosity increase and water retention cannot be obtained. If the content is outside the range of 25 to 75%, the printability of the coated paper will be poor.

(2) Monomer (B) In the monomer constituting the copolymer (water retaining agent for paper coating agent ) in the present invention, the monomer (B) is a carboxyl group-containing monomer, It is selected from a hydroxyl group-containing monomer, an amide group-containing monomer, and an amino group-containing monomer. These monomers (B) may be used alone or in combination of two or more.

Among the above monomers (B), preferred monomers are those represented by the following formulas (B-1) to (B-4).

Embedded image (Wherein, R ¹ is hydrogen or a methyl group, M is hydrogen, an alkali metal, an alkaline earth metal, ammonia, or a cation or onium of an organic base, and R ⁵ is a group having 2 to 3 carbon atoms.
An alkylene group of 0, n is an integer of 1 to 100, and R ⁶ and R ⁷ are hydrogen, methyl, ethyl, propyl, butyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, methoxymethyl A, an ethoxymethyl group, a propoxymethyl group, a butoxymethyl group,
—O— or —NH—, R ⁸ is — (CH ₂ ) ₂ —,
— (CH ₂ ) ₃ —, —CH ₂ C (CH ₃ ) ₂ CH ₂ —,
Or —CH ₂ CH (OH) CH ₂ — with R ⁹ and R ¹⁰
Is hydrogen, methyl, ethyl, propyl, butyl,
It represents a benzyl group, a hydroxyethyl group, a hydroxypropyl group, a dihydroxypropyl group, or a glycidyl group. R
⁵ alkylene group may be a single type or two or more in the same compound, each alkylene oxide corresponding to these alone addition, block addition, block random addition, or may be any of random addition. ).

The monomers represented by the general formulas (B-1) to (B-4) may be used alone or in combination of two or more. Among them, the monomer represented by the general formula (B-1) is particularly preferable. Specific examples of the monomer (B) are shown below.

Examples of the carboxyl group-containing monomer include acrylic acid and methacrylic acid as examples of the monomer represented by the general formula (B-1). In addition, monocarboxylic acid monomers such as crotonic acid, cinnamic acid and atropic acid, dicarboxylic acid monomers such as itaconic acid, maleic acid, fumaric acid, citraconic acid, and mesaconic acid, and acid anhydrides thereof And dicarboxylic acid monoalkyl ester monomers. Acrylic acid,
Methacrylic acid is preferred, and methacrylic acid is particularly preferred.

The carboxyl group-containing monomer may be a salt obtained by neutralizing a part or all of the monomer with a basic substance. Examples of the basic substance include lithium, Sodium, potassium, magnesium, calcium, ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, butylamine, monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, diethylenetriamine, hexamethylenediamine, pyridine, aniline , Cyclohexylamine, morpholine and the like. Among them, sodium salts, potassium salts and ammonium salts are preferred.

As examples of the hydroxyl group-containing monomer, examples of the monomer represented by the above general formula (B-2) include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl ( Meta)
Acrylate, polyoxyethylene mono (meth) acrylate, polyoxypropylene mono (meth) acrylate, polyoxybutylene mono (meth) acrylate, polyoxydecylene mono (meth) acrylate, polyoxidedecylene mono (meth) acrylate, poly Oxytetradecylene mono (meth) acrylate, polyoxyhexadecylene mono (meth) acrylate, polyoxyoctadecylene mono (meth) acrylate, polyoxyicosylene mono (meth) acrylate, polyoxytricontylene mono (meth) Acrylate, polyoxyethylene polyoxypropylene mono (meth) acrylate and the like can be mentioned. Other examples include glycerin mono (meth) acrylate, pentaerythritol mono (meth) acrylate, (meth) allyl alcohol, and glycerin mono (meth) allyl ether.

As an example of the amide group-containing monomer, an example of the monomer represented by the general formula (B-3) is (meth)
Acrylamide, N-methyl (meth) acrylamide,
N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-ethylol (meth) acrylamide, N-hydroxypropyl (meth) acrylamide, N -Methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide and the like. Other examples include diacetone (meth) acrylamide, maleic amide, and maleic imide.

As an example of the amino group-containing monomer, an example of the monomer represented by the above general formula (B-4) is (meth)
N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylamino-2-hydroxypropyl (meth) acrylate, N, N-dimethyl (meth) acrylate Aminoneopentyl, N, N-diethylaminoethyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N-diethylamino (meth) acrylate
2-hydroxypropyl, (meth) acrylic acid N, N-
Diethylaminoneopentyl, (meth) acrylic acid N,
N-dimethylaminoethylamide, N, N-dimethylaminopropylamide (meth) acrylate, N, N-dimethylamino-2-hydroxypropylamide (meth) acrylate, N, N-dimethylamino (meth) acrylate Neopentylamide, (meth) acrylic acid N, N-diethylaminoethylamide, (meth) acrylic acid N, N-
Examples thereof include diethylaminopropylamide, (meth) acrylic acid N, N-diethylamino-2-hydroxypropylamide, and (meth) acrylic acid N, N-diethylaminoneopentylamide. Other examples include vinylpyridine, aminostyrene, aminoalkylstyrene and the like.

The amino group-containing monomer may be a salt obtained by neutralizing a part or all of the monomer with an acidic substance. Examples of the acidic substance include hydrochloric acid and bromide. Hydrogen acid, sulfuric acid, phosphoric acid, methyl sulfate, ethyl sulfate, acetic acid,
Formic acid and the like.

The most preferred monomer among the monomers (B) is methacrylic acid.

The amount of the monomer (B) constituting the copolymer is 20 to 70%, preferably 30 to 60%. If the amount of the monomer (B) is less than 20%, sufficient viscosity increase and water retention cannot be obtained, and if it exceeds 70%, the viscosity of the coating liquid becomes too high. If the content is out of the range of 20 to 70%, the printability of the coated paper becomes poor.

(3) Monomer (C) In the monomer constituting the copolymer (water retention agent for paper coating agent ) in the present invention, the monomer (C) has a propenyl group and a polyoxyethylene group. Having a carbon number of 8 at the terminal opposite to the propenyl group side of the chain where the polyoxyethylene group is present.
It is selected from compounds having a long-chain saturated hydrocarbon group and / or a long-chain unsaturated hydrocarbon group having 8 or more carbon atoms. These monomers (C) may be used alone or in combination of two or more. The “propenyl group” is an expression containing two kinds of isomers, and is an expression containing a “1-propenyl group” and / or a “2-propenyl group (that is, an allyl group by a common name)” according to the IUPAC nomenclature. is there.

The monomer (C) is an essential monomer component of the monomers constituting the copolymer in the present invention. When the above-mentioned monomer (C) is used as one of the monomer components to obtain a copolymer, which is used as a water-retaining agent for paper coating agents, the viscosity of the coating solution at a low shear rate is reduced. The viscosity at high shear rates is significantly reduced and very high water retention is obtained. Therefore, the coating suitability, the quality of the coated paper, and the printability were remarkably improved, and it became possible to obtain a water retention agent having a very high level and a well-balanced performance.

Although there are many unclear reasons why the monomer (C) provides an excellent effect, a long-chain saturated hydrocarbon group introduced through a polyoxyethylene chain at the terminal of the copolymer side chain and It is considered that hydrophobic groups such as long-chain unsaturated hydrocarbon groups have a network structure in a stationary state or at a low shear rate in a coating liquid, and thus exhibit excellent effects on water retention and the like. Can be

Among the above monomers (C), preferred monomers are those represented by the following formulas (C-1) to (C-10).

Embedded image

Embedded image (In the formula, R ¹¹ represents hydrogen or a saturated hydrocarbon group having 1 to 22 carbon atoms, an unsaturated hydrocarbon group having 1 to 22 carbon atoms, a and a ′
Represents an integer of 5 to 100, and A, A 'and B represent -O- or-
The O-CO-, R ¹² and R ^{12 'is} a long chain saturated hydrocarbon group having 8 to 40 carbon atoms, an unsaturated hydrocarbon group having 8 to 40 carbon atoms, R ¹³ and R ^13' is 8 carbon atoms 30 is a long-chain alkylene group, b and b 'are integers of 1 to 5, R ¹⁴ is hydrogen or a saturated hydrocarbon group having 1 to 40 carbon atoms, an unsaturated hydrocarbon group having 1 to 40 carbon atoms, ¹⁵ represents an alkylene group having 3 to 30 carbon atoms, and c represents an integer of 0 to 20. One or more alkylene groups of R ¹³ and R ¹⁵ may be present in the same compound, and the alkylene oxides corresponding thereto may be any of single addition, block addition, block random addition, or random addition. ) The above general formula (C-
The monomers represented by 1) to (C-10) are used alone or in combination of two or more.

Specific examples of the monomer (C) are shown below. As an example of the monomer (C), as an example of the monomer represented by the general formula (C-1), when A is -O- (ether), (1) polyoxyethylene 2- (1 -Propenyl) a compound having a structure in which the terminal hydroxyl group of phenyl ether is etherified as follows: alkyl etherification alkenyl etherification cycloalkyl etherification aryl etherification alkyl aryl etherification aralkyl etherification aralkyl aryl etherification (2) Polyoxyethylene 2- (1-propenyl) -4
-A compound having a structure in which the terminal hydroxyl group of an alkylphenyl ether is etherified as described above, and a compound in which a 4-alkylphenyl group is a 6-alkylphenyl group in these compounds. (3) Polyoxyethylene 2- (1-propenyl) -4
Compounds having a structure in which the terminal hydroxyl group of -alkenylphenyl ether is etherified as described above, and compounds in which 4-alkenylphenyl group is 6-alkenylphenyl group among these compounds.

When A is -O-CO- (ester), (1) the terminal hydroxyl group of polyoxyethylene 2- (1-propenyl) phenyl ether has the following (a) to
Compound having a structure esterified as in (g) (a) alkyl esterification (b) alkenyl esterification (c) cycloalkyl esterification (d) aryl esterification (e) alkyl aryl esterification (f) aralkyl ester (G) Aralkyl aryl esterification (2) Polyoxyethylene 2- (1-propenyl) -4
A compound having a structure in which a terminal hydroxyl group of -alkylphenyl ether is esterified as described in (a) to (g) above, and a compound in which a 4-alkylphenyl group is a 6-alkylphenyl group in these compounds (3 ) Polyoxyethylene 2- (1-propenyl) -4
Compounds having a structure in which the terminal hydroxyl group of -alkenylphenyl ether is esterified as described in (a) to (g) above, and compounds in which 4-alkenylphenyl group is 6-alkenylphenyl group among these compounds. No.

The carbon number of the substituent at the 4- or 6-position of the 2- (1-propenyl) phenyl group of these monomers is from 0 (when hydrogen) to 22 and the repeating unit of polyoxyethylene is from 5 to 5. 100, and the alkyl group, the alkenyl group, the cycloalkyl group, the aryl group, the alkylaryl group, the aralkyl group, and the aralkylaryl group having 8 to 40 carbon atoms linked by a terminal ether bond or ester bond.

Among the monomers represented by the general formula (C-1), a monomer represented by the following general formula (C-1 ') is preferable.

[0038]

Embedded image

Examples of the monomer represented by the above general formula (C-1 ') include: when A is -O- (ether), (1) polyoxyethylene 2- (1-propenyl) phenyl ether Having a structure in which the terminal hydroxyl group is etherified as follows: alkyl etherification alkenyl etherification cycloalkyl etherification aryl etherification alkyl aryl etherification aralkyl etherification aralkyl aryl etherification (2) polyoxyethylene 2- (1-propenyl) -4
A compound having a structure in which the terminal hydroxyl group of nonylphenyl ether is etherified as described above,
And a compound in which a 4-nonylphenyl group is a 6-nonylphenyl group in these compounds. (3) Polyoxyethylene 2- (1-propenyl) -4
Compounds having a structure in which the terminal hydroxyl group of-(1-propenyl) phenyl ether is etherified as described above, and among these compounds, 4- (1-
A compound in which the (propenyl) phenyl group is a 6- (1-propenyl) phenyl group.

When A is -O-CO- (ester), (1) the terminal hydroxyl group of polyoxyethylene 2- (1-propenyl) phenyl ether has the following (a) to
Compound having a structure esterified as in (g) (a) alkyl esterification (b) alkenyl esterification (c) cycloalkyl esterification (d) aryl esterification (e) alkyl aryl esterification (f) aralkyl ester (G) Aralkyl aryl esterification (2) Polyoxyethylene 2- (1-propenyl) -4
Compounds having a structure in which the terminal hydroxyl group of -nonylphenyl ether is esterified as described in (a) to (g) above, and compounds in which 4-nonylphenyl group is 6-nonylphenyl group in these compounds (3 ) Polyoxyethylene 2- (1-propenyl) -4
Compounds having a structure in which the terminal hydroxyl group of-(1-propenyl) phenyl ether is esterified as described in the above (a) to (g);
A compound wherein the-(1-propenyl) phenyl group is a 6- (1-propenyl) phenyl group.

The substituent at the 4- or 6-position of the 2- (1-propenyl) phenyl group of these monomers is hydrogen, nonyl group or propenyl group, preferably hydrogen or nonyl group. The unit is 10-100
And preferably 15 to 80, and the number of carbon atoms of the alkyl group, alkenyl group, cycloalkyl group, aryl group, alkylaryl group, aralkyl group and aralkylaryl group bonded by a terminal ether bond or ester bond is 1
2 to 40, preferably an alkyl group or an alkenyl group, having 16 to 40 carbon atoms.

Examples of the monomer represented by the general formula (C-2) include compounds having a structure in which an alkylene oxide is added to a terminal hydroxyl group of the following ether compounds (1) to (5). And the like.

(1) Polyoxyethylene 2- (1-propenyl) phenyl ether (2) Polyoxyethylene 2- (1-propenyl) -4
-Alkylphenyl ether (3) polyoxyethylene 2- (1-propenyl) -6
-Alkylphenyl ether (4) polyoxyethylene 2- (1-propenyl) -4
-Alkenylphenyl ether (5) polyoxyethylene 2- (1-propenyl) -6
-Alkenyl phenyl ether.

The carbon number of the substituent at the 4- or 6-position of the 2- (1-propenyl) phenyl group of these monomers is 0 (when hydrogen) to 22 and the repeating unit of polyoxyethylene is 5 to 5. And the alkylene oxide added to the terminal hydroxyl group has 8 to 30 alkylene carbon atoms.
Wherein the repeating unit is 1 to 5.

Among the monomers represented by the general formula (C-2), a monomer represented by the following general formula (C-2 ') is preferable.

[0046]

Embedded image

Examples of the monomer represented by the above general formula (C-2 ') include those having a structure in which an alkylene oxide is added to a terminal hydroxyl group of the following ether compounds (1) to (5). And the like.

(1) Polyoxyethylene 2- (1-propenyl) phenyl ether (2) Polyoxyethylene 2- (1-propenyl) -4
-Nonylphenyl ether (3) polyoxyethylene 2- (1-propenyl) -6
-Nonylphenyl ether (4) polyoxyethylene 2- (1-propenyl) -4
-(1-propenyl) phenyl ether (5) polyoxyethylene 2- (1-propenyl) -6
-(1-propenyl) phenyl ether The 4- (1-propenyl) phenyl group of these monomers
Or the substituent at the 6-position is hydrogen, nonyl group or propenyl group, preferably hydrogen or nonyl group, and the repeating unit of polyoxyethylene is 10 to 100, preferably 15 to 80, and the terminal hydroxyl group The alkylene oxide has 12 to 30 alkylene carbon atoms,
It is preferably from 16 to 18, and the repeating unit is from 1 to 18.
3, preferably 1-2.

As an example of the monomer (C), the above-mentioned general formula (C)
Examples of the monomers represented by -3) to (C-8) include the following general formula (CP)

Embedded image Compounds having the structures of various derivatives from the precursor 1,2-dihydroxy-3- (2-propenyloxy) propane represented by

As an example of the monomer represented by the above general formula (C-3), a polyoxy group may be added to the hydroxyl group at the 2-position carbon of propane of the precursor represented by the above general formula (CP). An ethylene chain is bonded (ether bond to carbon at position 2), and the terminal of the polyoxyethylene chain is a long chain saturated hydrocarbon group having 8 to 40 carbon atoms or a long chain having 8 to 40 carbon atoms by an ether bond or an ester bond. A hydroxyl group at the 1-position carbon of propane which is bonded to an unsaturated hydrocarbon group and is unsubstituted, or a saturated hydrocarbon group having 1 to 40 carbon atoms or an unsaturated hydrocarbon group having 1 to 40 carbon atoms by an ether bond or an ester bond. Examples include compounds having a structure in which a hydrogen group is bonded to the 1-position carbon of propane and a hydroxyl group is substituted.

As an example of the monomer represented by the above general formula (C-4), the hydroxyl group at the 2-position carbon of the propane of the precursor represented by the above general formula (CP) is unsubstituted. Or a carbon number of 1 to 4 by an ether bond or an ester bond.
A saturated hydrocarbon group of 0 or an unsaturated hydrocarbon group having 1 to 40 carbon atoms is bonded to the 2-position carbon of propane to substitute a hydroxyl group, and a polyoxyethylene chain is substituted for the hydroxyl group of the 1-position carbon of propane. Is bonded (ether bond to carbon at position 1), and the terminal of the polyoxyethylene chain has 8 to 40 carbon atoms by an ether bond or an ester bond.
And a compound having a structure bonded to a long-chain saturated hydrocarbon group or a long-chain unsaturated hydrocarbon group having 8 to 40 carbon atoms.

As an example of the monomer represented by the above general formula (C-5), the hydroxyl group at the 2-position carbon of propane of the precursor represented by the above general formula (CP) may be a polyoxy group. An ethylene chain is bonded (ether bond to carbon at position 2), and the terminal of the polyoxyethylene chain is a long chain saturated hydrocarbon group having 8 to 40 carbon atoms or a long chain having 8 to 40 carbon atoms by an ether bond or an ester bond. A polyoxyethylene chain is bonded to an unsaturated hydrocarbon group and is bonded to the hydroxyl group of carbon at position 1 of propane (ether bond to carbon at position 1)
A compound having a structure in which the terminal of the polyoxyethylene chain is bonded to a long-chain saturated hydrocarbon group having 8 to 40 carbon atoms or a long-chain unsaturated hydrocarbon group having 8 to 40 carbon atoms by an ether bond or an ester bond. No.

As an example of the monomer represented by the above general formula (C-6), the hydroxyl group at the 2-position carbon of propane of the precursor represented by the above general formula (CP) may be a polyoxy group. An ethylene chain is bonded (ether bond to carbon at position 2), and a long-chain alkylene oxide having 8 to 30 carbon atoms is ring-opened at the end of the polyoxyethylene chain (ether bond),
And the hydroxyl group at the 1-position carbon of propane is unsubstituted or has 1 carbon atom by an ether bond or an ester bond.
Compounds having a structure in which a saturated hydrocarbon group having ４０40 or an unsaturated hydrocarbon group having 1 to 40 carbon atoms is bonded to the 1-position carbon of propane and a hydroxyl group is substituted.

As an example of the monomer represented by the above general formula (C-7), the hydroxyl group at the 2-position carbon of propane of the precursor represented by the above general formula (CP) is unsubstituted. Or a carbon number of 1 to 4 by an ether bond or an ester bond.
A saturated hydrocarbon group of 0 or an unsaturated hydrocarbon group having 1 to 40 carbon atoms is bonded to the 2-position carbon of propane to substitute a hydroxyl group, and a polyoxyethylene chain is attached to the hydroxyl group of the 1-position carbon of propane. Compounds having a structure in which a long-chain alkylene oxide having 8 to 30 carbon atoms is ring-opened (ether-bonded) to the end of the polyoxyethylene chain by bonding (ether-bonded to the carbon at position 1).

As an example of the monomer represented by the above general formula (C-8), a polyoxy group may be added to the hydroxyl group at the 2-position carbon of propane of the precursor represented by the above general formula (CP). An ethylene chain is bonded (ether bond to carbon at position 2), and a long-chain alkylene oxide having 8 to 30 carbon atoms is ring-opened at the end of the polyoxyethylene chain (ether bond),
In addition, a polyoxyethylene chain is bonded to the hydroxyl group of carbon at position 1 of propane (ether bond to carbon at position 1), and the terminal of the polyoxyethylene chain has 8 to 30 carbon atoms.
Ring-opening addition (ether bond) of long-chain alkylene oxide
Compounds having the following structures:

In the monomers (C-3) to (C-8), the repeating unit of the polyoxyethylene bonded to the carbon at the 1- or 2-position of propane of the precursor (CP) has 5 to 5 units.
100, and the long-chain saturated hydrocarbon group or long-chain unsaturated hydrocarbon group bonded to the terminal is an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an alkylaryl group, an aralkyl group, an aralkylaryl group, The number of carbon atoms is 8 to 40, the number of carbon atoms of the alkylene group of the long-chain alkylene oxide (ring-opening addition) bonded to the end of the polyoxyethylene chain is 8 to 30, and the repeating unit of oxyalkylene is 1 to 5 It is. Further, the saturated hydrocarbon group or unsaturated hydrocarbon group bonded to the 1- or 2-position carbon of propane of the precursor (CP) is an alkyl group, an alkenyl group,
Cycloalkyl group, aryl group, alkylaryl group,
They are an aralkyl group and an aralkylaryl group, and have 1 to 40 carbon atoms.

As an example of the monomer (C), the above-mentioned general formula (C)
As an example of the monomer represented by -9), when A is -O- (ether), 0 to 20 moles of ring-opening addition of an alkylene oxide having 3 to 30 carbon atoms is performed to a hydroxyl group of allyl alcohol; Ethylene oxide is added to the hydroxyl group at the terminal of the polyoxyalkylene by ring opening of 5 to 100 mol, and the terminal hydroxyl group is further alkylated, alkenyletherified, cycloalkyletherified, aryletherified, alkylaryletherified, aralkylether. And aralkyl aryl etherified compounds having a structure. In addition, the carbon number of the long-chain saturated hydrocarbon group or the long-chain unsaturated hydrocarbon group ether-bonded to these terminal hydroxyl groups is 8 to
40. When A is -O-CO- (ester), 0 to 20 moles of an alkylene oxide having 3 to 30 carbon atoms are ring-opened to the hydroxyl group of the allyl alcohol, and ethylene oxide is added to the hydroxyl group at the polyoxyalkylene terminal by 5 to 5 moles. A compound having a structure in which 100 mol of ring-opening addition is performed, and further, the terminal hydroxyl group is alkyl-esterified, alkenyl-esterified, cycloalkyl-esterified, aryl-esterified, alkylaryl-esterified, aralkyl-esterified, or aralkylaryl-esterified. No. The long-chain saturated hydrocarbon group or long-chain unsaturated hydrocarbon group ester-bonded to these terminal hydroxyl groups has 8 to 40 carbon atoms.

As an example of the monomer (C), the above-mentioned general formula (C)
As an example of the monomer represented by -10), 0 to 20 moles of an alkylene oxide having 3 to 30 carbon atoms is ring-opened to the hydroxyl group of allyl alcohol, and ethylene oxide is added to the hydroxyl group at the terminal of the polyoxyalkylene. 5
And a compound having a structure in which 8 to 30 long-chain alkylene oxides are ring-opened and added to the terminal hydroxyl group by 1 to 5 mol.

In the monomer (C), the compound represented by the general formula (C-
The monomers represented by 1) to (C-10) are preferable, and further, (C-1) to (C-6), (C-9), and (C-1)
The monomer represented by 0) is preferred. Particularly preferably, the above general formulas (C-1 ′), (C-2 ′), (C-4),
It is a monomer represented by (C-10).

The synthetic route of the monomer (C) is not particularly limited, and any synthetic route that can be used to obtain the disclosed compound as the monomer can be employed. In addition, monomer (C)
Is not particularly limited, and can be carried out by a known synthesis / purification method. For example, Japanese Patent Application Laid-Open
No. 100502, JP-A-63-54927, JP-A-6-54927
It is possible to refer to JP-A-3-214330, JP-A-63-319035 and JP-A-4-50204.

The amount of the monomer (C) constituting the copolymer is 0.1 to 30%, preferably 0.1 to 10%, more preferably 0.5 to 5%. If the amount of the monomer (C) is less than 0.1%, remarkably excellent water retention and the like cannot be obtained,
If it exceeds 30%, the viscosity increases, the water retention tends to decrease, the coatability decreases, and coated paper with extremely good printability cannot be obtained.

(4) Chain Transfer Agent In the polymerization of the copolymer (water retention agent for paper coating agent) in the present invention, a chain transfer agent is used if necessary. Selection of the chain transfer agent includes 2,4-diphenyl-4-methyl-1-
The use of pentene (abbreviated as DPMP) is particularly preferred in terms of performance as a water retention agent. The amount of DPMP used is preferably set to 0 to 2%, more preferably 0 to 0.5%, based on the total amount of the monomers (A), (B), and (C).

Although a chain transfer agent other than DPMP can be used in combination, the amount is set to such an extent as not to impair the effect on water retention performance.

Examples of the chain transfer agent other than DPMP include methanethiol, ethanethiol, propanethiol, butanethiol, octanethiol, dodecanethiol, benzenethiol, toluenethiol, α-naphthalene thiol, β-naphthalene thiol, mercaptomethanol , Mercaptoethanol, mercaptopropanol, mercaptobutanol, thioglycolic acid, methyl thioglycolate, ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, n-octyl thioglycolate, 2-ethylhexyl thioglycolate, thioglycol Dodecyl acid, octadecyl thioglycolate, benzyl thioglycolate, methoxyethyl thioglycolate, methoxybutyl thioglycolate, β-merca Topropionic acid, methyl β-mercaptopropionate, ethyl β-mercaptopropionate, propyl β-mercaptopropionate, butyl β-mercaptopropionate, n-octyl β-mercaptopropionate, 2-ethylhexyl β-mercaptopropionate, β-mercaptopropionate dodecyl, β-
Thiols (mercaptans) such as octadecyl mercaptopropionate, benzyl β-mercaptopropionate, methoxyethyl β-mercaptopropionate, methoxybutyl β-mercaptopropionate, trimethylolpropane tris- (β-mercaptopropionate),
Halogenated hydrocarbons such as carbon tetrachloride, chloroform, carbon tetrabromide, bromoform, bromotrichloroethane, bromobenzene or carbon halides, amines, nitro compounds, alcohols, aldehydes, sulfides, disulfides, sulfoxides , Sulfones, other hypophosphites, cumene, anthracene, allyl compounds, diisobutylene, terpinolene, β-terpinene, γ-terpinene, 1,4-cyclohexadiene, 2,
-Methyl-1,4-cyclohexadiene and the like. These can be used alone or in combination of two or more.

(5) Crosslinking Agent In the polymerization of the copolymer (water retaining agent for paper coating agent) in the present invention, a crosslinking agent having two or more radically polymerizable double bonds is used as necessary. Regarding the type of the crosslinking agent, if the compound has two or more radical polymerizable double bonds,
There is no particular limitation. Specific examples include, for example, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, glycerin di (meth) acrylate, glycerin tri (meth) acrylate, diethylene glycol di (meth) acrylate, diallyl phthalate, diallyl Malate, diallyl fumarate, allyl (meth) acrylate, N, N'-methylenebis (meth) acrylamide, divinylbenzene, and the like.

The amount of the cross-linking agent used is the above-mentioned monomer (A),
The total amount of (B) and (C) is preferably set to 0 to 2%, and more preferably 0 to 0.5%.

(6) Copolymer (Water Retention Agent) The copolymer (water retention agent for paper coating agent) of the present invention is obtained by copolymerizing the above monomers (A), (B) and (C). It is composed of the obtained copolymer, the amount of monomer (A) is 25 to 75%, the amount of monomer (B) is 20 to 70%, and the amount of monomer (C) is 0.1 to 75%. 30%, and preferably the amount of (A) is 40 to
70%, the amount of (B) is 30 to 60%, and the amount of (C) is 0.1%.
1 to 10%, and more preferably 0.1 to 10% for (C).
5 to 5%.

The use of the monomer (C) is an essential component of the copolymer of the present invention.
If it is outside the range of 30%, various remarkably excellent performances as a water retention agent such as a desired water retention property cannot be obtained, and the printability of a coated paper coated with a coating liquid (paper coating agent) also becomes poor. Very good ones may not be obtained.

The molecular weight of the copolymer of the present invention is not particularly limited, but usually the average molecular weight (weight average molecular weight) is 3,0.
The average molecular weight is preferably from 200,000 to 150,000.
00,000. When the average molecular weight of the copolymer is 3,000
If it is less than 0, sufficient viscosity increase and water retention may not be obtained, and if it exceeds 30,000,000, the viscosity of the coating solution may be too high. In addition, 3,000-30,
Outside the range, the printability of the coated paper may be poor.

The monomers constituting the copolymer may be polymerized in any of block, random, alternating, and graft forms.

(7) Polymerization Method The method for producing the copolymer of the present invention is not basically limited,
It is possible to employ any of solution polymerization, emulsion polymerization, suspension polymerization, and bulk polymerization.However, solution polymerization and emulsion polymerization are preferred.Emulsion polymerization is particularly preferred in terms of performance as a water retention agent. Optimal.

When the desired copolymer is polymerized by the solution polymerization method or the emulsion polymerization method, water and an organic solvent such as benzene, toluene, xylene, hexane, cyclohexane, and the like are used as a polymerization solvent (medium).
Heptane, octane, chloromethane, chloroethane, chlorofluoromethane, chlorofluoroethane, fluoromethane, fluoroethane, methanol, ethanol, isopropyl alcohol, butyl alcohol, ethylene glycol, diethylene glycol, propylene glycol, glycerin, pentaerythritol, ethyl acetate,
Acetone, methyl ethyl ketone, methyl isobutyl ketone, dioxane, dimethylformamide, dimethyl sulfoxide and the like can be mentioned, and these solvents may be used in combination.

Examples of the polymerization initiator include benzoyl peroxide, tert-butyl peroxide, lauroyl peroxide, cumyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide,
Azobisisobutyronitrile, 2,2'-azobis-
(2,4-dimethylvaleronitrile), hydrogen peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, 2,2'-azobis- (2-amidinopropane)-
Hydrochloride, redox-based initiator (hydrogen peroxide-ferrous chloride, ammonium persulfate-sodium acid sulfite, ascorbic acid (salt), Rongalite, etc.), O-allyl OO-t-butyl peroxycarbonate, OO-
t-butyl O-2- (methacryloyloxy) ethyl peroxycarbonate, t-butyl (E) -3-isopropoxycarbonyl peroxyacrylate, 1,1-
Radical donors such as di-t-butylperoxy-2-methylcyclohexane and 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane. In addition, radicals may be generated by photopolymerization using ultraviolet rays, electron beams, radiation, or the like. In this case, a photosensitizer or the like may be used.

(8) Monomer (D) When the above emulsion polymerization method is employed, the emulsifier to be used is represented by the following general formulas (D-1), (D-2) and (D-3). It is preferable to use one or more types selected from reactive surfactants, and (D-1) is particularly preferable.

Embedded image (Wherein, f is an integer of 1 to 100, and R ¹⁹ has 10 to 10 carbon atoms.
30 alkyl group, alkyl phenyl group, an aralkyl phenyl group, R ²⁰ represents an alkyl group having 12 to 30 carbon atoms. ).

The above general formulas (D-1), (D-2) and (D
The reactive surfactant represented by -3) is preferably used in an amount of 0.1 to 10% by weight based on all monomers.

When the emulsion polymerization method is employed, an emulsifier other than the above-mentioned reactive surfactant may be used, or may be used in combination.

Examples of the emulsifier for emulsion polymerization other than the above-mentioned reactive surfactant include fatty acid salts, rosinates, sulfated fatty acid salts, alkyl sulfonates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl sulfo salts. Fatty acid ester salt, dialkyl sulfosuccinate acid ester, polyoxyalkylene alkyl ether sulfosuccinate monoester salt, polyoxyalkylene alkenyl ether sulfosuccinate monoester salt, polyoxyalkylene aryl ether sulfosuccinate monoester salt, alkyl diphenyl ether disulfonate, sulfuric acid Oil, sulfated fatty acid ester salt, alkyl sulfate ester salt, alkenyl sulfate ester salt, polyoxyalkylene alkyl ether sulfate salt, polyoxyalkylene alkyl Ether carboxylate, polyoxyalkylene alkenyl ether sulfate, polyoxyalkylene aryl ether sulfate, alkyl phosphate, polyoxyalkylene alkyl ether phosphate, polyoxyalkylene alkenyl ether phosphate, poly Anionic surfactants such as oxyalkylene aryl ether phosphate ester salts, polyoxyalkylene alkyl ethers, polyoxyalkylene alkenyl ethers, polyoxyalkylene aryl ethers, polyoxyalkylene alkyl aryl ethers, polyoxyalkylene alkyl esters, polyoxyalkylenes Alkenyl esters,
Polyoxyalkylenealkylarylester, polyoxyalkylenealkylamine, N, N-dihydroxyethylalkylamide, polyoxyalkylenealkylamide, glycerin fatty acid ester, polyglycerin fatty acid ester, pentaerythritol fatty acid ester, polyoxyalkylenepentaerythritol alkyl ester, Nonionic surfactants such as sorbitan fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyalkylene sucrose fatty acid ester, polyoxyalkylene, alkylamine salt, alkylammonium salt, alkylaralkylammonium salt, alkyl Cationic surfactants such as pyridinium salts and alkylpicolinium salts, amino acid types, betaine types, Amphoteric surfactants such as sulfonic acid type, sulfate type and phosphate type, casein, formalin condensate of β-naphthalenesulfonic acid, polycarboxylate, polyvinyl alcohol, cellulose derivative, poly (meth) acrylamide, styrene- Maleic acid copolymers and derivatives thereof, polyamide-epichlorohydrin resin, amine-epichlorohydrin resin, (poly) alkylenepolyamine-epichlorohydrin resin, and high molecular surfactants such as poly (diallylamine) -epichlorohydrin resin. The surfactants can be used alone or in combination of two or more.

In the present invention, the water retention agent of the present invention can be used as it is or as a neutralized emulsifier for polymerization during its production.

In addition, a pH buffer, a chelating agent and the like may be used at the time of polymerization.
Sodium hydrogen carbonate, sodium carbonate, sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium phosphate, sodium acetate, potassium acetate and the like.Examples of the chelating agent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate and the like. No.

In the polymerization of the above copolymer, the total amount of the monomer (A), (B), (C) a polymerization initiator and, if necessary, a mixture comprising a chain transfer agent, a cross-linking agent, a surfactant and the like is reduced. 5 to 90% of the whole, preferably 10 to 80%,
The remainder is a medium (water, organic solvent). The polymerization temperature is from 5 to 200C, preferably from 50 to 100C. Other conditions and methods may be carried out in accordance with general polymerization conditions and methods. For example, regarding the method of adding a monomer or the like to a polymerization system, a batch addition method, a continuous addition method, a split addition method, or the like is used. And these may be adopted.

(9) The copolymer (water retention agent) is targeted
Paper Coating Agent The paper coating agent targeted by the copolymer of the present invention is an aqueous dispersion mixture mainly composed of a pigment, a binder (adhesive), a dispersant, water, and various additives. Used for the production of coated paper.

Among the components of the coating solution, pigments include, for example, kaolin, calcined clay, heavy calcium carbonate, light calcium carbonate, talc, satin white, barium sulfate, aluminum hydroxide, titanium oxide, zinc oxide, plastic pigment Examples of the binder include styrene / butadiene-based latex, methyl methacrylate / butadiene-based latex, and carboxyl-modified latexes thereof, synthetic rubber-based aqueous dispersions such as vinyl acetate-based latex, and starch, modified starch, and the like.
Examples include natural water-soluble polymers such as casein, soy protein, and modified soy protein. Examples of the dispersant include polycarboxylate, polyacrylamide, modified polyacrylamide, pyrophosphate, hexametaphosphate, and the like.Examples of the water-proofing agent include urea resin, melamine resin, polyamide resin, polyamine resin, and polyamide. Polyurea resin, polyamine polyurea resin, glyoxal,
Zirconium ammonium carbonate and the like can be mentioned. As other additives, a lubricant, an antifoaming agent, a softener, a wetting agent, a preservative, an optical brightener, a release agent, a leveling agent, an antioxidant, and the like are appropriately used. Further, within a range not hindering the performance of the water retention agent of the present invention, carboxymethyl cellulose,
Methylcellulose, modified starch, sodium alginate,
It is also possible to use one or more conventional water retention agents such as polyvinyl alcohol.

Usually, the binder is used in an amount of 3 to 20 parts by dry weight and the dispersant is used in an amount of 0 to 100 parts by weight of the pigment in the coating liquid (hereinafter simply referred to as “parts”). .0
1 to 0.5 part, and the solids concentration of the coating liquid with the remainder being water is about 40 to 70%. The water retention agent of the present invention is usually p
H adjustment is required, and the pH is adjusted to about 7 to 11 with a basic substance such as sodium hydroxide or ammonia. In addition, the water retention agent of the present invention is preferably operable to adjust the pH after adding the water retention agent after preparing the coating liquid, but it is also possible to add the water retention agent after adjusting the pH of the coating liquid. Alternatively, the water retention agent may be added after adding a certain amount of the basic substance, and then the pH may be adjusted. Alternatively, the water retention agent alone may be added to the coating solution after the pH adjustment.

The amount of the water retention agent of the present invention is not particularly limited, and may be appropriately increased or decreased according to required physical properties such as viscosity. However, it is usually 0.01 to 5 parts, preferably 0.03 parts, in terms of solid component based on 100 parts of the pigment in the coating liquid.
About 1 part is used.

(10) Application of Paper Coating Agent to Paper The method of applying the coating liquid intended for the present water retention agent to paper is not particularly limited, and may be in accordance with a known method, for example, an air knife coater. It is coated on paper by a coating device such as a blade coater, a roll coater, a bar coater, and a curtain coater. At this time, the solid content concentration of the coating solution is usually 40 to 7
Although it is about 0%, when the water retention agent of the present invention is used, coating at a high concentration of 65% or more is possible, and the water content can be reduced. The coating liquid is applied on one side or both sides of the paper, and the coating amount is usually about 5 to 25 g / m ^{2 on} one side in terms of dry weight. After drying, normal calendering and supercalendering are performed. 40-600g basis weight as base paper for coating
/ M ² high-quality paper, medium-quality paper, paperboard, and printing paper such as coated paper. When the water retaining agent of the present invention is used, high shear viscosity is low and fluidity is excellent, so that high-speed coating at a coating speed of 1,500 m / min or more is possible.

By using the water-retaining agent of the present invention, the paper coating composition is given an appropriate thickening property at a low shear rate, good fluidity at a high shear rate, and extremely excellent water retention property. In addition, the coated paper is excellent in printability, and can reduce drying energy by increasing the density and improve productivity by increasing the coating speed. Compared with the conventional synthetic water retention agent, the agent of the present invention is superior in the above points.

[0087]

EXAMPLES Hereinafter, specific embodiments and effects of the present invention will be described with reference to examples and comparative examples, but the technical scope of the present invention is not limited thereto.
In the following, “parts” and “%” are based on weight.

[0088]

[Table 1]

[Table 2]

[Monomer belonging to monomer (A)] MA: methyl acrylate (A-1) EA: ethyl acrylate (A-1) BA: n-butyl acrylate (A-1) i-BA: isobutyl Acrylate (A-1) 2EHA: 2-ethylhexyl acrylate (A-1) DA: Decyl acrylate (A-1) SA: Stearyl acrylate (A-1) MMA: Methyl methacrylate (A-1) EMA: Ethyl methacrylate (A -1) BMA: n-butyl methacrylate (A-1) HMA: hexyl methacrylate (A-1) 2EHMA: 2-ethylhexyl methacrylate (A-
1) VAc: vinyl acetate (A-2) VN: vinyl nonanoate (A-2) St: styrene (A-3) α-MSt: α-methylstyrene (A-3).

[Monomer belonging to monomer (B)] AA: acrylic acid (B-1) MAA: methacrylic acid (B-1) HEMA: 2-hydroxyethyl methacrylate (B-
2) AAm: acrylamide (B-3) DAM: N, N-dimethylaminoethyl methacrylate (B-4).

[Monomer belonging to monomer (C)]

Embedded image

Embedded image

[Others] DPMP: 2,4-diphenyl-4-methyl-1-pentene (chain transfer agent) DM: n-dodecanethiol (chain transfer agent) t-DM: tert-dodecanethiol (chain transfer agent) EGDM: ethylene glycol dimethacrylate (crosslinking agent) DAP: diallyl phthalate (crosslinking agent) NPP-30: polyoxyethylene 2- (1-propenyl) -4-nonylphenyl ether (EO repeating unit 30)

Embedded image (D-1 (1), D-2 (1), D-3 (1): reactive surfactant).

1. Production Example of Copolymer (Water Retaining Agent) Example 1 10 parts of ethyl acrylate, 5 parts of methacrylic acid, di (2
-Ethylhexyl) sulfosuccinate sodium
5 parts, 0.2 parts of sodium bicarbonate, and 110 parts of water were placed in a reaction vessel equipped with a dropping device, a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube and mixed, and mixed under a nitrogen atmosphere. After heating to 80.degree.
An aqueous solution in which 2 parts were dissolved in 10 parts of water was added to initiate polymerization. Five minutes after the addition of the aqueous solution, an emulsion obtained by mixing 51 parts of ethyl acrylate, 28 parts of methacrylic acid, 6 parts of C-1 (1), 0.5 part of sodium di (2-ethylhexyl) sulfosuccinate, and 100 parts of water The mixture in the state was dropped from the dropping device over 2 hours. During this time, the temperature was maintained at 80 ° C., and the mixture was further stirred at 80 ° C. for 3 hours, and then cooled to 30 ° C. to obtain a copolymer.

Example 2 10 parts of methyl methacrylate, 30 parts of ethyl acrylate
Part, methacrylic acid 52 parts, C-2 (1) 8 parts, DPMP
0.01 part, azobisisobutyronitrile 0.6 part, trisodium nitrilotriacetate 0.01 part, polyoxyethylene nonyl phenyl ether (ethylene oxide (hereinafter the same as "EO") repeating unit: 20) 9 parts, and 200 parts of water was placed in a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, mixed, stirred at 85 ° C. for 4 hours under a nitrogen atmosphere, and cooled to 30 ° C. A polymer was obtained.

Example 3 0.5 parts of polyoxyethylene nonyl phenyl ether sulfate ammonium (EO repeating unit: 20) was added to a reaction vessel equipped with a dropping device, a stirring device, a reflux condenser, a thermometer, and a nitrogen inlet tube, and 130 parts of water was added, stirred, mixed and heated to 75 ° C., and an aqueous solution of potassium persulfate (a solution of 0.1 part of potassium persulfate and 10 parts of water) was added to the reaction vessel under a nitrogen atmosphere. Minutes later, a monomer emulsion described below, which was prepared in advance, was continuously dropped into the reaction vessel over 3 hours, and stirring was continued for another 5 hours (while the reaction vessel was maintained at 75 ° C.), cooled to 30 ° C. A polymer was obtained. The above monomer emulsion was composed of 45 parts of ethyl acrylate, 5 parts of n-butyl acrylate, and 4 parts of methacrylic acid.
5 parts, C-3 (1) 5 parts, polyoxyethylene nonylphenyl ether sulfate ammonium (EO repeating unit: 20) 0.5 parts, D-1 (1) 2 parts, and water 1
This was prepared by emulsifying 00 parts with a homomixer.

Example 4 65 parts of ethyl acrylate, 4.8 parts of 2-ethylhexyl acrylate, 30 parts of methacrylic acid, C-4 (1)
0.2 parts, ethylene glycol dimethacrylate 0.5
Parts, 0.1 part of benzoyl peroxide, 14 parts of sodium dodecylbenzenesulfonate, and 300 parts of water are mixed in a reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer, and mixed at 60 ° C. for 10 hours. After stirring, the mixture was cooled to 30 ° C. to obtain a copolymer.

Example 5 15 parts of ethyl acrylate, 18 parts of vinyl acetate, 5 parts of vinyl nonanoate, 55 parts of methacrylic acid, 4 parts of acrylic acid,
C-5 (1) 3 parts, lauroyl peroxide 0.4 part,
Polyoxyethylene nonyl phenyl ether sulfosuccinate monoester disodium (EO repeating unit: 1
2) 3 parts, and 200 parts of water, a stirrer, a reflux condenser,
The mixture was placed in a reaction vessel equipped with a thermometer and a nitrogen inlet tube, mixed, stirred at 90 ° C. for 3 hours in a nitrogen atmosphere, and then cooled to 30 ° C. to obtain a copolymer.

Example 6 5 parts of isobutyl acrylate, 20 parts of styrene, 5 parts of α-methylstyrene, 50 parts of methacrylic acid, C-6 (1)
20 parts, DPMP 0.5 part, sodium persulfate 0.5
Part, sodium bisulfite 0.5 part, sodium phosphate 0.4 part, sodium hydroxide 0.2 part, D-3 (1) 5
Parts, and 400 parts of water were placed in a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, and mixed.
The mixture was stirred at 30 ° C. for 24 hours under a nitrogen atmosphere to obtain a copolymer.

Example 7 60 parts of ethyl methacrylate, 5 parts of stearyl acrylate, 25 parts of methacrylic acid, 15 parts of 2-hydroxyethyl methacrylate, 5 parts of C-7 (1), 0.5 part of lauroyl peroxide, polyoxyethylene nonyl Sodium phenyl ether sulfate (EO repeating unit:
6) 5 parts and 200 parts of water are mixed with a stirrer, a reflux condenser,
The mixture was placed in a reaction vessel equipped with a thermometer and a nitrogen inlet tube, mixed, stirred at 80 ° C. for 4 hours in a nitrogen atmosphere, and then cooled to 30 ° C. to obtain a copolymer.

Example 8 40 parts of methyl acrylate, 20 parts of n-butyl methacrylate, 5 parts of methacrylic acid, 30 parts of acrylamide, C
-8 (1) 1 part, 2,2'-azobis- (2,4-dimethylvaleronitrile) 0.3 part, D-2 (1) 1 part, propylene glycol 25 parts and water 400 parts were stirred. The mixture was placed in a reaction vessel equipped with an apparatus, a reflux condenser, a thermometer, and a nitrogen inlet tube, mixed, stirred at 60 ° C. for 2 hours and at 70 ° C. for 10 hours under a nitrogen atmosphere, and then cooled to 30 ° C. A polymer was obtained.

Example 9 30 parts of ethyl acrylate, 2 parts of 2-ethylhexyl methacrylate, 45 parts of methacrylic acid, 15 parts of N, N-dimethylaminoethyl methacrylate, C-9 (1) 3
Part, 0.01 part of diallyl phthalate, 4 parts of 2,2'-azobis (2-amidinopropane) -hydrochloride, 15 parts of sodium dodecylbenzenesulfonate, polyoxyethylene nonylphenyl ether (EO repeating unit:
30) 5 parts, 100 parts of isopropyl alcohol, and 200 parts of water were mixed in a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, and mixed at 75 ° C. in a nitrogen atmosphere at 10 ° C. After stirring for an hour, the mixture was cooled to 30 ° C. to obtain a copolymer.

Example 10 10 parts of ethyl acrylate, di (2-ethylhexyl)
1.5 parts of sodium sulfosuccinate, 0.2 part of sodium hydrogen carbonate, and 110 parts of water were mixed in a reaction vessel equipped with a dropping device, a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube. After heating to 80 ° C. under a nitrogen atmosphere, an aqueous solution in which 0.2 part of ammonium persulfate was dissolved in 10 parts of water was added to initiate polymerization. Five minutes after the addition of the aqueous solution, 10 parts of ethyl acrylate, 10 parts of methacrylic acid, 30 parts of acrylic acid, 40 parts of C-10 (1), 0.5 part of di (2-ethylhexyl) sulfosuccinate sodium, and 100 parts of water The mixture in the emulsion state was added dropwise over 2 hours from the dropping device. During this time, the temperature was maintained at 80 ° C., and the mixture was further stirred at 80 ° C. for 3 hours. Obtained.

Comparative Example 1 10 parts of ethyl acrylate, 5 parts of methacrylic acid, di (2
-Ethylhexyl) sulfosuccinate sodium
5 parts, 0.2 parts of sodium bicarbonate, and 110 parts of water were placed in a reaction vessel equipped with a dropping device, a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube and mixed, and mixed under a nitrogen atmosphere. After heating to 85.degree.
An aqueous solution in which 2 parts were dissolved in 10 parts of water was added to initiate polymerization. Five minutes after the addition of the aqueous solution, 51 parts of ethyl acrylate, 34 parts of methacrylic acid, 0.5 part of sodium di (2-ethylhexyl) sulfosuccinate, and 1 part of water
A mixture in the form of an emulsion in which 00 parts were mixed was dropped from the dropping device over 2 hours. During this time, the temperature was maintained at 80 ° C., and the mixture was further stirred at 80 ° C. for 3 hours. I got

Comparative Example 2 10 parts of methyl acrylate, 38 of ethyl acrylate
Parts, methacrylic acid 52 parts n-dodecyl mercaptan 0.
001 parts, azobisisobutyronitrile 0.6 part, trisodium nitrilotriacetate 0.01 part, polyoxyethylene nonylphenyl ether sulfate ammonium (EO repeating unit: 20) 9 parts, and water 200 parts, a stirrer, The mixture was placed in a reaction vessel equipped with a reflux condenser, a thermometer, and a nitrogen inlet tube and mixed.
After stirring for an hour, the mixture was cooled to 30 ° C. to obtain a copolymer.

Comparative Example 3 45 parts of ethyl acrylate, 5 parts of n-butyl acrylate
Parts, methacrylic acid 50 parts, potassium persulfate 0.1 part, polyoxyethylene nonylphenyl ether sulfate ammonium (EO repeating unit: 10) 2 parts, and water 2
Forty parts were mixed in a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, stirred at 75 ° C. for 8 hours under a nitrogen atmosphere, cooled to 30 ° C., and weighed. A coalescence was obtained.

Comparative Example 4 65 parts of ethyl acrylate, 5 parts of 2-ethylhexyl acrylate, 30 parts of methacrylic acid, 0.1 part of benzoyl peroxide, 14 parts of sodium dodecylbenzenesulfonate and 300 parts of water were stirred in a stirrer and reflux cooled. The mixture was placed in a reaction vessel equipped with a vessel, a thermometer, and a nitrogen inlet tube, mixed, and stirred at 60 ° C. for 10 hours under a nitrogen atmosphere.
This was cooled to obtain a copolymer.

Comparative Example 5 20 parts of ethyl acrylate, 80 parts of methacrylic acid, 0.6 part of azobisisobutyronitrile, 0.01 part of trisodium nitrilotriacetate, ammonium polyoxyethylene nonylphenyl ether sulfate (EO repeating unit: 20 parts) 9) and 200 parts of water were placed in a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, mixed, and stirred at 85 ° C. for 4 hours under a nitrogen atmosphere.
After cooling to ℃, a copolymer was obtained.

Comparative Example 6 Hexyl methacrylate 8 parts, decyl acrylate 29
Part, methacrylic acid 63 parts, sodium polyoxyethylene stearyl ether sulfate (EO repeating unit:
25) 14 parts and 228 parts of water are dropped, a stirring device,
The mixture was placed in a reaction vessel equipped with a reflux condenser and a thermometer and mixed, and 38 parts of a 0.5% potassium persulfate aqueous solution was dropped from the dropping device over 3 hours, and the reaction temperature was 80 to 10 at this time.
It was kept at 0 ° C. After maintaining the same temperature for 3 hours after dropping,
After cooling to 0 ° C., a copolymer according to Example 1 of JP-A-8-188987 was obtained.

Comparative Example 7 190 parts of water, 2.0 parts of sodium dodecylbenzenesulfonate, 0.02% of sodium ethylenediaminetetraacetate
The mixture was placed in a pressure-resistant reaction vessel equipped with a dropping device, a stirrer, a thermometer, and a nitrogen inlet tube, mixed, heated to 85 ° C., and the inside of the reaction vessel was purged with nitrogen, 55 parts of ethyl acrylate, 10 parts of vinyl acetate, A mixture consisting of 35 parts of methacrylic acid and 0.1 part of t-dodecanethiol (t-dodecyl mercaptan), 50 parts of water, 0.8 parts of sodium dodecylbenzenesulfonate, 0.8 parts of sodium hydroxide and 0 parts of sodium persulfate And a mixture of 0.8 parts were simultaneously added dropwise at 85 ° C. over 3 hours. After further stirring for 1 hour, the mixture was cooled to 30 ° C. to obtain a copolymer according to Example 1 of JP-A-61-43607.

Comparative Example 8 [Liquid 1] comprising 15 parts of water and 1 part of Emulgen 920 (manufactured by Kao Corporation), 60 parts of n-butyl acrylate,
Styrene 30 parts, methacrylic acid 2.5 parts, 2-hydroxyethyl methacrylate 7.5 parts, Emulgen 920
4 parts, Neoperex 05 (manufactured by Kao Corporation)
[Liquid 2] composed of 2 parts, 0.2 parts of ammonium persulfate, and 70 parts of water, and [Liquid 3] composed of 10 ml of 2% NaHSO 3 aqueous solution were prepared. [Liquid 1] was placed in a reaction vessel equipped with a dropping device, a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, and after nitrogen replacement, 1/10 of [Liquid 2] and [Liquid 3] 1/10 amount was added, and after the reaction started, the remaining [Liquid 2] and [Liquid 3] were added dropwise over 3 hours. At this time, the reaction temperature was kept at 50 ° C. After the addition, the reaction temperature is increased to 50.
℃ 1 hour, cool to 30 ℃, ammonia water p
H was adjusted to 7, and Example 1 of JP-A-52-118015 was used.
Was obtained.

Comparative Example 9 10 parts of ethyl acrylate, 5 parts of methacrylic acid, di (2
-Ethylhexyl) sulfosuccinate sodium
5 parts, 0.2 parts of sodium bicarbonate, and 110 parts of water were placed in a reaction vessel equipped with a dropping device, a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube and mixed, and mixed under a nitrogen atmosphere. After heating to 80.degree.
An aqueous solution in which 2 parts were dissolved in 10 parts of water was added to initiate polymerization. Five minutes after the addition of the aqueous solution, 51 parts of ethyl acrylate, 28 parts of methacrylic acid, and polyoxyethylene 2-
(1-propenyl) -4-nonylphenyl ether (E
O repeating unit 30) 6 parts, di (2-ethylhexyl)
0.5 parts of sodium sulfosuccinate and 100 parts of water
The mixture in the emulsion state was added dropwise over 2 hours from the dropping device. During this time, the temperature was maintained at 80 ° C., and the mixture was further stirred at 80 ° C. for 3 hours. Obtained. The obtained copolymer was found to have a weight average molecular weight of 2,000,000 by GPC measurement.

[0112] 2. Preparation of Paper Coating Agent (Coating Solution) a) Offset Printing Paper Coating Agent Example 1a Water and dispersant (Daiichi Kogyo Seiyaku Co., Ltd.) Co., Ltd .: Sharoll AN-103P)
While stirring one part, kaolin clay (ECC Corp.
40 parts of heavy calcium carbonate (FMT-90 manufactured by Fimatec Co., Ltd.) and 60 parts of phosphate esterified starch (MS # 4 manufactured by Japan Food Processing Co., Ltd.)
600) 1 part, styrene / butadiene-based latex (L-1161 manufactured by Asahi Kasei Kogyo Co., Ltd.), lubricant (San Nopco Co., Ltd .: Nopcoat C-104-HS)
0.5 part of a water-proofing agent (Sumitomo Chemical Co., Ltd .: Sumireze Resin 650) 0.3 part was added, and 0.05 part of the water retention agent (copolymer) obtained in Example 1 was further added. After doing
The pH was adjusted to 9.0 with an aqueous NaOH solution, and the solid content was 68%.
(A heavy calcium carbonate, a dispersant, a latex, a lubricant, a water-proofing agent, and a water-retaining agent were all added in terms of solid content).

Paper Coating Examples 2a to 10a Using the water retention agents obtained in Examples 2 to 10, coating solutions were prepared in exactly the same manner as in Paper Coating Example 1a.

Comparative Paper Coating Examples 1a to 9a Using the water retention agents obtained in Comparative Examples 1 to 9, coating solutions were prepared in exactly the same manner as in the above paper coating examples 1a.

The above offset printing paper coating compositions were evaluated for the paper coating compositions described below (low-speed shear viscosity, high-speed shear viscosity, static water retention, dynamic water retention) and coated paper evaluation (white paper gloss). Degree, print gloss, dry pick surface strength, wet pick surface strength, blister resistance).

B) Gravure printing paper coating agent Paper coating agent example 1b Water and a dispersant in an amount such that the final solid content of the coating solution is 63% (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd .: Sharoll AH-103P) ) 0.
While stirring 2 parts, kaolin clay (ENGELHARD M & C Corp.
Manufactured by Asahi Kasei Kogyo Co., Ltd .; 100 parts of Ultra White 90)
-1176) 5 parts, and sodium carboxymethylcellulose (Daiichi Kogyo Seiyaku Co., Ltd .: Cellogen B)
S) After adding 0.05 part and 0.2 part of the water retention agent (copolymer) obtained in Example 1, p was added with an aqueous ammonia solution.
H was adjusted to 9.0, and a coating liquid having a solid content of 63% was prepared (the addition amounts of a dispersant, a latex, and a water retention agent were all in terms of solid content).

Paper Coating Examples 2b to 10b Using the water retention agents obtained in Examples 2 to 10, coating solutions were prepared in exactly the same manner as in Paper Coating Example 1b.

Comparative Paper Coating Examples 1b to 9b Using the water retention agents obtained in Comparative Examples 1 to 9, coating solutions were prepared in exactly the same manner as in Paper Coating Example 1b.

The above gravure printing paper coating agent was evaluated for the paper coating agent described below (low-speed shear viscosity, high-speed shear viscosity, static water retention, dynamic water retention), and the evaluation of the coated paper (ink receiving , Smoothness, dot reproducibility).

[0120] 3. Performance evaluation method of paper coating agent (low-speed shear viscosity) BM type viscometer (Tokyo Keiki Seisakusho Co., Ltd.)
Was measured at 25 ° C. at 60 rpm.

(High-Speed Shear Viscosity) Using a Hercules-type viscometer (manufactured by Kumagaya Riki Kogyo Co., Ltd.), 440 at 25 ° C.
The viscosity was measured at 0 rpm (E bob) and 8800 rpm (F bob). The lower the value, the better the fluidity under a high shear rate.

(Static water retention) Measured at 25 ° C by the SD Warren ring cell method. The higher this value, the better the static water retention.

(Dynamic Water Retention) By pressure dehydration method, 200
Measured at 25 ° C. for 30 seconds under a pressure of kPa, a 5 μm polycarbonate filter was used. The lower this value (vs. blank), the better the dynamic water retention.

[0124] 4. Preparation of Coated Paper (Coating of Paper Coating Agent) Paper Coating Agent Examples 1a to 10a, Comparative Paper Coating Agent Examples 1a to 9a,
Paper coating examples 1b to 10b and comparative paper coating examples 1b to 9
The coating liquid obtained in b) was applied to one side of high-quality paper having a basis weight of 84 g / m ² using a Fonten blade coater at a coating speed of 160 g / m ^2.
After applying a coating amount of 15 g / m ² at 0 m / min, drying with an air cap drier (150 ° C. × 30 sec), humidity control for 24 hours (20 ° C., 65% humidity), super calendar treatment (nip) Pressure 100kg / cm, 60
C.) twice to produce a coated paper.

[0125] 5. Performance Evaluation Method of Coated Paper (White Paper Gloss) Measured at an incident angle of 75 ° using a gloss meter (manufactured by Murakami Color Research Laboratory Co., Ltd.) based on JIS: P-8142. The higher the value, the better the white paper gloss.

(Print Gloss) After solid printing with offset ink using an RI type printability tester (manufactured by Mei Seisakusho Co., Ltd.),
JI using a gloss meter (Murakami Color Research Laboratory Co., Ltd.)
S: Measured at an incident angle of 60 ° based on P-8142.
The higher the value, the better the print gloss.

(Dry Pick Surface Strength) The degree of picking when printing with a RI-type printing suitability tester without using dampening water was evaluated on a five-point scale. AA, A, B,
C and D.

(Wet Pick Surface Strength) The degree of picking when printing was performed using dampening water with an RI-type printing suitability tester was evaluated on a five-point scale. AA, A, B,
C and D.

(Blister resistance) Blister resistance was measured by an oil bath method (silicone oil). The higher the numerical value, the better the blister resistance.

(Smoothness) Evaluation was carried out by Oken type smoothness tester (manufactured by Asahi Seiko Co., Ltd.) based on JIS: P-8119. The larger the value, the better the smoothness.

(Ink Acceptability) The K & N ink acceptability was measured and the rate of decrease in reflectance was shown. The larger the value, the better the ink acceptability.

(Dot Reproducibility) Printing was performed using a dot gravure plate by a Ministry of Finance printing department type gravure printing suitability tester, and the dot missing rate in the highlight portion was evaluated using an image analyzer. The lower the numerical value, the lower the dot loss rate and the better the gravure printing suitability.

6. Performance Evaluation Results of Paper Coating Agent and Coated Paper The results are shown in the following [Table 3] to [Table 6].

[0134]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

From the results shown in Tables 3 and 4, the coating liquids using the copolymers of the respective examples exhibited an appropriate thickening property at a low shear rate, and showed a high solids content even at a high shear rate. Regardless, it can be seen that the viscosity at a high shear rate is low, the fluidity is excellent, and the water retention is extremely excellent. Also, from the results in [Table 5] above, the coated paper obtained by high-speed application of the coating liquid using the copolymer of each example has high white paper glossiness and print glossiness, and has dry and wet topical surface strengths. From the results of [Table 6], the coated paper having excellent smoothness, ink receptivity and halftone dot reproducibility, that is, excellent printability was obtained. It is clear that it can be obtained.

[0136]

By using the copolymer (water retention agent) of the present invention, the paper coating agent is given an appropriate thickening property at a low shear rate and a good fluidity at a high shear rate, and is extremely excellent. It provides excellent water retentivity and excellent coating aptitude, and enables reduction of drying energy by increasing the concentration and improvement of productivity by increasing the coating speed.

The water retention agent of the present invention is superior to the conventional water retention agent in the above-mentioned points. Further, the drying energy cost can be reduced by increasing the concentration of the coating solution, and the productivity can be improved only by increasing the coating speed. Rather, it greatly contributes to improving the quality of coated paper, such as improving printability.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C08F 226/00 C08F 226/00 F term (Reference) 4J100 AB02P AB04P AB07R AB16S AE18R AG02P AG04P AG70S AJ00Q AJ02Q AL02P AL03P AL04P AL08P AL08Q AL09Q AL62S AL65S AL67S AM15Q AM19Q AM21Q BA02R BA02S BA03R BA08R BA15R BA29Q BA31Q BC04P BC43P CA05 CA23 FA04 JA13 4L055 AG11 AG27 AG48 AG62 AG63 AG64 AG65 AG70 AG71 AG72 AG74 AG76 FA89 AG97 AH17 A37 AH23

Claims (8)

[Claims] 1. A water retention agent for a paper coating agent comprising a copolymer obtained by copolymerizing the following monomers (A) to (C). (A) at least one monomer selected from the group consisting of (meth) acrylate monomers, vinyl carboxylate monomers, and styrene monomers. (B) at least one monomer selected from the group consisting of a carboxyl group-containing monomer, a hydroxyl group-containing monomer, an amide group-containing monomer, and an amino group-containing monomer. (C) having a propenyl group and a polyoxyethylene group,
And a compound having a long-chain saturated hydrocarbon group having 8 or more carbon atoms and / or a long-chain unsaturated hydrocarbon group having 8 or more carbon atoms at the terminal opposite to the propenyl group side of the chain where the polyoxyethylene group is present. And at least one monomer. 2. The monomer (A) has the following general formula (A-1):
To (A-3), wherein the monomer (B) is represented by the following general formulas (B-1) to (B-4).
Wherein the monomer (C) is composed of at least one selected from the group consisting of monomers represented by the following general formulas (C-1) to (C-1):
The water retention agent for a paper coating material according to claim 1, comprising at least one selected from the group consisting of monomers represented by 0). Embedded image (Wherein, R ¹ represents hydrogen or a methyl group, and R ² has 1 to 1 carbon atoms.
22 alkyl groups, alkenyl groups, cycloalkyl groups,
A cycloalkenyl group, an aryl group, an aralkyl group, or an aralkenyl group, R ³ represents an alkyl group having 1 to 17 carbon atoms, a chloromethyl group, or a phenyl group, and R ⁴ represents hydrogen or an alkyl group having 1 to 4 carbon atoms. Show. ) (Wherein, R ¹ is hydrogen or a methyl group, M is hydrogen, an alkali metal, an alkaline earth metal, ammonia, or a cation or onium of an organic base, and R ⁵ is a group having 2 to 3 carbon atoms.
An alkylene group of 0, n is an integer of 1 to 100, and R ⁶ and R ⁷ are hydrogen, methyl, ethyl, propyl, butyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, methoxymethyl A, ethoxymethyl group, propoxymethyl group, butoxymethyl group,
O-, or -NH-, ^{R 8} is _{- (CH 2) 2 -,} -
(CH ₂ ) ₃ —, —CH ₂ C (CH ₃ ) ₂ CH ₂ —, or —CH ₂ CH (OH) CH ₂ —, wherein R ⁹ and R ¹⁰ are hydrogen, methyl, ethyl, propyl, A butyl group, a benzyl group, a hydroxyethyl group, a hydroxypropyl group, a dihydroxypropyl group, and a glycidyl group are shown. R
⁵ alkylene group may be a single type or two or more in the same compound, each alkylene oxide corresponding to these alone addition, block addition, block random addition, or may be any of random addition. ) Embedded image (In the formula, R ¹¹ represents hydrogen or a saturated hydrocarbon group having 1 to 22 carbon atoms, an unsaturated hydrocarbon group having 1 to 22 carbon atoms, a and a ′
Represents an integer of 5 to 100, and A, A 'and B represent -O- or-
The O-CO-, R ¹² and R ^{12 'is} a long chain saturated hydrocarbon group having 8 to 40 carbon atoms, an unsaturated hydrocarbon group having 8 to 40 carbon atoms, R ¹³ and R ^13' is 8 carbon atoms 30 is a long-chain alkylene group, b and b 'are integers of 1 to 5, R ¹⁴ is hydrogen or a saturated hydrocarbon group having 1 to 40 carbon atoms, an unsaturated hydrocarbon group having 1 to 40 carbon atoms, ¹⁵ represents an alkylene group having 3 to 30 carbon atoms, and c represents an integer of 0 to 20. One or more alkylene groups of R ¹³ and R ¹⁵ may be present in the same compound, and the alkylene oxides corresponding thereto may be any of single addition, block addition, block random addition, or random addition. ) 3. The monomer (C) is represented by the following general formula (C-1)
The water retention agent for paper coating agents according to claim 1 or 2, comprising at least one selected from the group consisting of monomers represented by ') to (C-2'). Embedded image (Wherein, R ¹⁶ represents hydrogen, a propenyl group, a nonyl group, d represents an integer of 10 to 100, and A represents —O— or —O—CO—
R ¹⁷ is a saturated hydrocarbon group having 12 to 40 carbon atoms, an unsaturated hydrocarbon group having 12 to 40 carbon atoms, and R ¹⁸ is a carbon group having 12 to 40 carbon atoms.
30 alkylene groups, e is an integer of 1 to 3, and one or more alkylene groups of R ¹⁸ may be present in the same compound. ) 4. The content of the monomer (A) in all monomers is 25 to 75% by weight, the content of the monomer (B) is 20 to 70% by weight, The water retention agent for paper coating agents according to any one of claims 1 to 3, wherein the content ratio of the monomer (C) is 0.1 to 30% by weight. 5. A chain transfer agent 2,4-diphenyl-4-methyl-1-pentene is used in an amount of 0 to 2% by weight based on the total amount of monomers.
The water retention agent for a paper coating material according to any one of claims 1 to 4, comprising the copolymer used. 6. The copolymer according to claim 1, wherein the copolymer comprises a crosslinking agent having two or more radically polymerizable double bonds in an amount of 0 to 2% by weight based on all monomers. The water retention agent for paper coating agents according to 1. 7. The copolymer as set forth in claim 1, wherein said copolymer is polymerized by an emulsion polymerization method and has the following general formula (D-1), (D-2) or (D-
The copolymer according to claim 1, comprising a copolymer which is polymerized by using one or more kinds selected from reactive surfactants represented by 3) with respect to all monomers in an amount of 0.1 to 10% by weight. The water retention agent for paper coating agents according to any one of claims 1 to 7. Embedded image (Wherein, f is an integer of 1 to 100, and R ¹⁹ has 10 to 10 carbon atoms.
30 alkyl group, alkyl phenyl group, an aralkyl phenyl group, R ²⁰ represents an alkyl group having 12 to 30 carbon atoms. ) 8. The water retention agent for a paper coating material according to claim 1, which is used for a paper coating material comprising at least a pigment, a binder, a dispersant, and water.