JPH032999B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a paper surface treatment agent. Specifically, the present invention relates to a fluidity improver for paper coating paints and a water retention agent, which are mainly composed of pigments and binders. In recent years, the productivity of coated paper has improved, cost reductions,
High-density, high-speed coating is attracting attention and consideration from the viewpoint of energy saving. As a method to increase the solid content of paper coating paints for high-concentration coating, a method is to use calcium carbonate in combination with the pigment, which gives a lower viscosity than clay, and a method to use latex as a binder by reducing natural binders such as starch. Methods that use a large amount of starch, or so-called all-latex formulations that do not use starch at all, are used. In such highly concentrated coating colors, problems such as insufficient water retention and poor fluidity arise, so carboxymethyl cellulose sodium salt (hereinafter referred to as
Attempts have been made to add water retention agents and fluidity improvers such as CMC), sodium alginate, and alkali-sensitive latex. However, these water retention agents and fluidity improvers cannot provide sufficient fluidity properties, and have the disadvantage that scratches, streaks, etc. are likely to occur, especially when coated with a high-speed coater. The present inventors have conducted repeated research to improve these drawbacks, and as a result they have arrived at the present invention. That is, the present invention provides a polymer [referred to as polyether (A)] in which ethylene oxide or ethylene oxide and propylene oxide are added to a compound having active hydrogen selected from the group consisting of alcohols, carboxylic acids, amines, amides, and urethanes. ]; (meth)acrylic acid, (meth)acrylamide,
A water-soluble ethylenically unsaturated monomer (B-1) selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid and vinylsulfonic acid, and ( An ethylenically unsaturated monomer selected from the group consisting of (B-2) an ethylenically unsaturated monomer having a meth)acrylate group
(B): and other ethylenically unsaturated monomers (C) if necessary, (A) is 20 to 80% by weight, the total of (B) and (C) is 20 to 80% by weight, and If less than 25 mol% of (C) in the total of (B) and (C) is graft polymerized and (B-2) is used as (B), the (B-2) unit is further added after graft polymerization. It consists of a graft polymer (G) obtained by hydrolysis, and the viscosity of a 5% by weight aqueous solution is 2 to 50,000 cps,
A paper surface treatment agent that is water-soluble and has a non-thermal melting coating after drying, and is a fluidity modifier for paper coating paints and a water retention agent;
This is a paper surface treatment method using a paper coating paint containing 0.001 to 50 parts by weight of a binder (calculated as solid content) in the paper coating paint. Examples of the polyether (A) constituting the graft polymer used in the present invention include alkylene oxide addition polymers of compounds having active hydrogen such as alcohols, carboxylic acids, amines, amides, and urethanes. Specific examples of these active hydrogen-containing compounds include the following. Saturated monovalent substances such as methanol, ethanol, propanol, butanol, pentanol, cyclopentanol, hexanol, cyclohexanol, octanol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, etc. Alcohol, ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, decanediol, pinacol, glycerin, butanetriol, hexanetriol, and erythrites, pentites, hexites such as pentaerythritol and sorbitol, and polyglycerin;
Saturated polyhydric alcohols such as polyvinyl alcohol, and polymeric polyhydric alcohols such as polysaccharides and their derivatives such as cellulose, starch, dextrin, and guar gum. Aromatic alcohols such as benzyl alcohol, benzhydryl alcohol, triphenyl carbinol, and phenylethyl alcohol. Phenols represented by phenol, hydroquinone, catechol, pyrogallol, cresol, nitrophenol, aminophenol, naphthol and derivatives such as phenolsulfonic acid and its salts, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, trimethylacetic acid, Monobasic saturated carboxylic acids such as caproic acid, heptanoic acid, caprylic acid, pelargonic acid, lauric acid, and stearic acid and polybasic acids such as oxalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, dimer acid, and butanetricarboxylic acid Saturated carboxylic acid.
Aromatic carboxylic acids such as phenyl acid, benzoic acid, toluic acid, phthalic acid, naphthoic acid, and cinnamic acid. Primary amines such as methylamine, ethylamine, propylamine, butylamine, laurylamine, stearylamine, aniline, secondary amines such as dimethylamine, dimethylamine, dipropylamine, dibutylamine, dilaurylamine, distearylamine, and , ethylenediamine,
Polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. Amides obtained by dehydration condensation reaction between the above carboxylic acids and ammonia or the above amines, such as formamide, acetamide, propionic acid amide, butyric acid amide, valeric acid amide, caproic acid amide, stearic acid amide, oxalic acid amide, succinic acid amide, etc. Acid amides such as acid amide, malonic acid amide, and glutaric acid amide. Substituted amides such as N-ethylpropionamide. Polyamides are typified by polyamides produced by dehydration condensation of polybasic acids such as adipic acid and dimer acid and polyamines such as diethylenetriamine. Monoisocyanates such as methyl isocyanate, ethyl isocyanate, propyl isocyanate, butyl isocyanate, polyfunctional isocyanates such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, alcohols or amines, polyether polyols and polyol compounds A mono- or polyurethane compound obtained by reacting a polyester polyol consisting of a polybasic acid with a polyester polyol. Oxycarboxylic acids such as glycolic acid and lactic acid,
Compounds with two or more types of active hydrogen, such as alkatoluamines such as monoethanolamine, diethanolamine, triethanolamine, and aminomethylpropanol, amino acids such as glycine, alanine, and lysine, and acid alkanolamides such as lauric acid monoethanolamide. can also be used. As the alkylene oxide added to these active hydrogen compounds, ethylene oxide or a combination of ethylene oxide and propylene oxide can be used. When using ethylene oxide and propylene oxide, the method of addition can be random. In addition to polyethers obtained by the above-mentioned alkylene oxide addition polymerization method to compounds having active hydrogen, polyethers (A) include polyethers obtained by dehydration condensation using an acid alkali of a polyhydric alcohol or a metal oxide as a catalyst. For example, polyethers obtained by dehydration condensation of ethylene glycol or glycerin at about 250°C using sodium hydroxide as a catalyst, alcoholates of polyhydric alcohols obtained by reacting polyhydric alcohols with alkali metal hydrides or alkali metals, and polyhalogen compounds. A polyether obtained by the demetallization reaction of ethylene glycol, for example, a polyether obtained by reacting sodium hydride with ethylene glycol and heating dichloroethane and a sodium alcoholate above 150°C, which has a polyhydric alcohol and an unsaturated bond. Polyethers obtained by addition reactions with compounds, such as polyethers obtained by reacting glycerin and acetylene with boron trifluoride as a catalyst at approximately 250°C and 15 atm, also include polyethers obtained by various methods. . If necessary, these polyethers can be used by modifying their terminal hydroxyl groups by various methods. Examples of methods for modifying the terminal hydroxyl group include esterification using a monobasic acid such as acetic acid or stearic acid, etherification using a monohydric alcohol such as propyl alcohol or stearyl alcohol, or monoisocyanate such as octadecyl isocyanate. Phenyl isocyanate, etc., or monohydric alcohol, 1
A urethane prepolymer of a basic acid, a secondary amine, etc. and a diisocyanate, such as methanol, lauryl alcohol or diisopropylamine, is reacted with xylylene diisocyanate by a conventional method using about 2 to 2.5 times the molar amount of isocyanate groups to active hydrogen. There are methods such as conventional urethanization using a urethane prepolymer. These polyethers can also be used after being crosslinked into a dimer or higher form using a polyfunctional isocyanate, a polybasic acid, or a polyfunctional epoxy resin. The molecular weight of polyether (A) is usually 2 million to 2 million, preferably 1000 to 800,000, more preferably 2000.
~100,000. Active hydrogen 1 to which alkylene oxide is added
Regarding the molecular weight per piece, it is usually 150 to 200.
10,000, preferably 500,000 to 800,000, more preferably
1,000 to 100,000, and the number of moles of alkylene oxide added per active hydrogen is usually 3 to 45,000, preferably 10 to 18,000, and more preferably 20 to 2,300.
It is. If the molecular weight per active hydrogen is less than 150, the water retention effect will be insufficient and the molecular weight will be 200.
If it is greater than 10,000, the viscosity of the paper-coated paint increases too much, making it difficult to improve fluidity, which is not preferred. Among these, preferred are alkylene oxide addition polymers of monohydric and dihydric alcohols,
Alkylene oxide addition polymers of basic acids and dibasic acids, alkylene oxide adducts of primary amines and secondary amines, alkylene oxide adducts of polyamides consisting of monobasic acids or dibasic acids and polyamines, and monoisocyanates or diisocyanates. It is an alkylene oxide addition polymer of polyurethane and polyalkylene oxide. More preferably, alkylene oxide addition polymers of dihydric alcohols, alkylene oxide addition polymers of dibasic acids, alkylene oxide addition polymers of primary amines, alkylene oxide adducts of polyamides consisting of dibasic acids and polyamines, and diisocyanates. It is an alkylene oxide adduct of polyurethane consisting of polyalkylene oxide. As the ethylenically unsaturated monomer (B) [hereinafter referred to as monomer (B) or (B)] constituting the graft polymer, the graft polymer obtained by polymerization can be used as is (meth) Water-soluble monomer (B-1) consisting of acrylic acid, (meth)acrylamide, 2-acrylamine-2-methylpropanesulfonic acid, styrenesulfonic acid or vinylsulfonic acid
[Hereinafter referred to as monomer (B-1) or (B-1)]
and an ethylenically unsaturated monomer (B-2) having a (meth)acrylate group that can be derived into a carboxy group by hydrolysis and can be used after hydrolysis.
[Hereinafter referred to as monomer (B-2) or (B-2)]
can be used. Specific examples of monomer (B-1) include the following. 1 (Meth)acrylic acid (means acrylic acid and methacrylic acid. The same expressions will be used hereinafter.) 2 Sodium (meth)acrylate, trimethylamine (meth)acrylate, triethanolamine (meth)acrylate, etc. Water-soluble salts (alkali metal salts, ammonium salts, amine salts, etc.) of (meth)acrylic acid. 3 (meth)acrylamide. 4 2-acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid and vinylsulfonic acid. 5 Sulfonic acid group-containing monomers such as alkali metal salts, ammonium salts, and amine salts of the above-mentioned sulfonic acid group-containing monomers. Preferred among these are (meth)acrylic acid, styrenesulfonic acid, 2-acrylamido-2methylpropanesulfonic acid, and , their sodium, potassium or ammonium salts, and (meth)acrylamide, more preferably (meth)acrylic acid, maleic acid and (meth)acrylamide. Specific examples of monomer (B-2) include the following. 1 Alkyl esters of ethylenically unsaturated carboxylic acids having (meth)acrylate groups such as methyl (meth)acrylate, ethyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate Among these, preferred ones can be easily hydrolyzed Methyl (meth)acrylate and ethyl (meth)acrylate are preferred, with which a graft polymer can be easily obtained and a high grafting rate can be obtained, and methyl (meth)acrylate is more preferred. The graft polymer of the present invention is obtained by copolymerizing the water-soluble monomer (B) with another ethylenically unsaturated monomer (C) [hereinafter referred to as monomer (C) or (C)]. It can be anything. Examples of such monomer (C) include the following, in addition to the alkyl esters of ethylenically unsaturated carboxylic acids and nitrile group-containing monomers listed above as monomer (B-2). 1 Ethylenically unsaturated alcohols such as (meth)allylic alcohol, hydroxyethyl (meth)
Acrylate, Hydroxypropyl (meth)acrylate, Diethylene diglycol mono(meth)acrylate, Dipropylene glycol mono(meth)acrylate, Triethylene diglycol mono(meth)acrylate, Tripropylene glycol mono(meth)acrylate, Poly-oxyethylene- Oxypropylene glycol mono(meth)acrylate (Poly-oxyethylene-oxypropylene glycol may be random or block. The same applies hereinafter.) Polyols such as alkylene glycols, polyalkylene glycols, and polyhydric alcohols such as glycerin mono(meth)acrylate. Hydroxyl or ether groups represented by ethylenically unsaturated ethers such as ethylenically unsaturated esters and poly-oxyethylene-oxypropylene glycol mono(meth)allyl ether (the terminal hydroxyl group may be etherified or esterified) Containing monomer: 2 N-methylacrylamide, N-propylacrylamide, N-hexylacrylamide,
N,N-dimethylacrylamide, N,N-dipropylacrylamide, N-methylol(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N-N-dihydroxymethyl(meth)acrylamide, N-N-dihydroxyethyl( An amide group-containing monomer represented by ethylenically unsaturated N-mono- or dialkyl-substituted (meth)acrylamide such as meth)acrylamide, vinyl lactams such as N-vinylpyrrolidone, and the like. 3 Dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, morpholinoethyl (meth)acrylate,
Amino group-containing esters of ethylenically unsaturated mono- or dicarboxylic acids such as dimethylaminoethyl fumarate 4 2-vinylpyridine, 4-vinylpyridine,
Amino group-containing monomers represented by heterocyclic vinyl compounds such as N-vinylpyridine and N-vinylimidazole. 5 N,N,N-trimethyl-N-(meth)acryloyloxyethylammonium chloride, 2
-Hydroxy, 3-(meth)acryloyloxypropyltrimethylammonium chloride, and other quaternary ammonium base-containing monomers 6 Styrene, ethylene, propylene, butene,
Water-insoluble monomers such as vinyl chloride. 7 Esters of ethylenically unsaturated alcohols such as vinyl acetate and (meth)allyl acetate; 8 Di- or polyvinyl compounds such as divinylbenzene, trivinylbenzene, divinylethylene glycol, divinyl sulfone, divinyl ether and divinyl ketone; N,N- Bisacrylamides such as methylene bis(meth)acrylamide, ethylene glycol, polyethylene glycol, polypropylene glycol, poly-oxyethylene-oxypropylene glycol, glycerin, polyols such as trimethylolpropane and pentaerythritol and (meth)acrylic acid, maleic acid and Unsaturated di- or polyester compounds with unsaturated mono- or polycarboxylic acids such as fumaric acid, polyepoxides such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, and unsaturated carboxylic acids such as (meth)acrylic acid. Saturated di- or polyester compounds, di- or poly(meth)allyl ether compounds of the above polyols such as polyethylene glycol allyl ether, di- or poly(meth)allyl ester compounds of polycarboxylic acids such as diallyl phthalate, diallyl adipate, polyethylene diglycol mono Ester compounds of mono(meth)acryether of polyols such as allyl ether acrylate and unsaturated carboxylic acids, and polyisocyanates such as di(meth)acrylic acid carbamyl ester of hydroxymethyl(meth)acrylate and xylylene diisocyanate. A compound having at least two polymerizable double bonds, such as a carbamyl ester compound obtained from a hydroxyl group-containing monomer. 9 At least one polymerizable double bond represented by glycidyl (meth)acrylate, N-methylol (meth)acrylamide, etc. and at least one functional group that can react with a carboxyl group, a hydroxyl group, an amide group, etc. Compounds with Among these, preferred is methyl (meth), which is easily copolymerized and can easily obtain a high grafting rate.
Alkyl esters of (meth)acrylic acid such as acrylates, ethylenically unsaturated esters of polyols such as hydroxyethyl (meth)acrylate, poly-oxyethylene-oxypropylene glycol mono(meth)acrylate, N-methylacrylamide, N-mono- or dialkyl-substituted acrylamides such as N-N-dimethylacrylamide, vinyl lactams such as N-vinylpyrrolidone, styrene, esters of ethylenically unsaturated alcohols such as vinyl acetate, divinylethylene glycol, divinyl sulfone, etc. polyvinyl compounds, and bisacrylamides such as N-N-methylenebis(meth)acrylic acid amide, more preferably alkyl esters of (meth)acrylic acid such as methyl (meth)acrylate, and hydroxyethyl (meth)acrylate. ethylenically unsaturated esters of polyols such as, vinyllactams such as N-vinylpyrrolidone, styrene, vinyl acetate, divinylethylene glycol, divinylbenzene, and N,N-methylenebis(meth)
It is acrylamide. Unsaturated monomers having two or more unsaturated double bonds can impart water resistance or a change in flow properties to the graft polymer. Furthermore, if necessary, the graft polymer of the present invention may be used with the following crosslinking agent (D) which can be crosslinked with (A), (B) or (C) in addition to the above (C) for the purpose of imparting water resistance and changing flow characteristics. ) [hereinafter referred to as crosslinking agent (D) or (D)] may be used in combination. As such a crosslinking agent (D), a compound having at least two reactive functional groups or a compound capable of forming an ionic crosslinking can be used, and specific examples thereof include the following. Periodic table groups, such as calcium hydroxide, calcium chloride, calcium carbonate, calcium oxide, magnesium chloride, magnesium oxide, aluminum chloride, zinc chloride and nickel chloride,
hydroxides, halides, carbonates, oxides and acetates of polyvalent metals such as groups, borates such as borax,
and polyvalent metal compounds capable of forming ionic crosslinks, typified by polyvalent metal alcoholates such as aluminum isopropylate. Preferred among these are hydroxides, halides, carbonates and oxides of polyvalent metals such as calcium, magnesium or aluminum;
borates such as borax, more preferably calcium, magnesium or aluminum or hydroxides of polyvalent metals such as aluminum;
halides, carbon salts and oxides, borax salts such as borax. In the graft polymer of the present invention, the ratio of polyether (A) to monomer (B) and monosteric solid (C) is 20 to 80% (weight%, hereinafter referred to as weight%). In contrast, the total amount of monomers (B) and (C) is 20-80%, preferably (A) is 20-70%, and the total amount of (B) and (C) is 30-80%. . (A) is 20%
If it is less than 80%, fluidity decreases, and if it exceeds 80%, water resistance decreases, which is not preferable. When copolymerizing or graft polymerizing other ethylenically unsaturated monomers (C), less than 25 mol% of (C) is used in the total of (B) and (C), and as (C) When using an unsaturated monomer having two or more polymerizable double bonds or an unsaturated monomer having one polymerizable double bond and a functional group that reacts with (A) or (B), (C) is (B)
and (C) in an amount of less than 10 mol %, preferably less than 6 mol %, more preferably less than 3 mol %. When (C) is within the above range, the resulting graft polymer is basically non-thermofusible and has excellent heat resistance. When (C) exceeds the above range, it is not preferable because the fluidity properties and the heat resistance of the resulting graft polymer are also reduced. As monomer (B),
When (B-2) is used, it can be made to fall within the above range after hydrolysis. Crosslinking agent (D)
Although the preferred amount used varies depending on the type of crosslinking agent (D), it is usually less than 10 mol%, preferably less than 6 mol%, more preferably 3 mol%, based on the total of (B), (C) and (D). If the amount of the crosslinking agent (D) exceeds the above range, the fluidity improving effect will decrease, which is not preferable. As a method for polymerizing polyether (A), monomer (B) and, if necessary, other monomers (C), a normal graft polymerization method can be used, such as a method using a polymerization catalyst, ultraviolet rays, Examples include methods of irradiating with electron beams, radiation, etc., but a method using a polymerization catalyst is preferred because the polymer can be easily obtained.
Specific examples of polymerization catalysts include persulfate-based catalysts such as ammonium persulfate, sodium persulfate, and potassium persulfate, ceric salt-based catalysts such as ceric ammonium nitrate, and redox catalysts such as hydrogen peroxide-based catalysts, and azobisisobutyrocarbon catalysts. Examples include radical polymerization catalysts such as nitrile and benzoyl peroxide. Among these, preferred are persulfate-based, ceric salt-based, and hydrogen peroxide-based redox catalysts that provide a high grafting rate and favorable viscoelasticity. In the polymerization of the present invention, if necessary, as a polymerization solvent, water, water-soluble organic solvents such as methanol, ethanol, acetone, methyl ethyl ketone, and dimethyl formamide, water-insoluble organic solvents such as toluene, xylene, etc. Mixtures can be used. Especially as (B) (B
When -1) is used, a polymerization solvent is used because the graft polymer of the polyether loses thermal meltability as the polymerization progresses. Preferred polymerization solvents are water and mixtures of water and the water-soluble organic solvents mentioned above. Additionally, additives such as acetaldehyde, chloroform, carbon tetrachloride, and dodecyl mercaptan can also be used to adjust the degree of polymerization. In addition, in the present invention, when a polymerization catalyst is used, the polymerization temperature varies depending on the type of catalyst, but is usually 10 to 150℃,
Preferably it is 20-100°C. Examples of polymerization methods include 1. (A), (B), (C)
and a method of simultaneously mixing and reacting a polymerization catalyst,
2. A method of reacting while dropping a polymerization catalyst into a mixed system of (A), (B), and (C), 3. A method of reacting (B) and (C) simultaneously into a mixed system of (A) and a polymerization catalyst. or a method in which either (B) or (C) is reacted by dropping the other first,
4. A method of reacting while dropping a mixture of (B), (C), and a polymerization catalyst into (A), 5. Polymerization into a mixed system of (A) and either (B) or (C). Method of dropping a mixture of catalyst and remaining monomer, 6. (A), polymerization catalyst and (B)
or (C), by dropping the remaining monomers into the mixed system; 7. After polymerizing (A) and either (B) or (C), the remaining monomers There are various methods for further reacting the polymer, and the properties and performance of the resulting graft polymers vary, and a preferred polymerization method can be selected depending on the desired performance. Hydrolysis carried out in the present invention can be carried out using conventional methods. For example, monomer (B-
Hydrolysis may be carried out by adding sodium hydroxide or potassium hydroxide and, if necessary, water to the polymer containing 2) or an aqueous solution thereof, and stirring at usually 10 to 100°C. Using (B-2) as monomer (B), (B-2)
A part of the monomer may remain unhydrolyzed, and this unhydrolyzed (B-2) may correspond to the other monomer (C). In the graft polymer of polyether (A), monomer (B) and other monomer (C) in the present invention,
The carboxyl group may be in the form of free, salt or partially neutralized partial salt. However, especially when water or a mixture of water and a water-soluble organic solvent is used as the polymerization solvent in graft polymerization, and a monomer containing a carboxyl group-containing monomer is used as (B-1), the graft polymer generated during polymerization is Since this may cause poor solubility in water, the carboxyl group is preferably polymerized as a water-soluble salt or partial salt such as sodium, potassium or ammonium to increase water solubility. Further, the obtained graft polymer is preferably in the form of a salt or partial salt from the viewpoint of ease of handling and dissolution. Salts include alkali metal salts such as sodium and potassium, ammonium salts, alkyl amines such as monomethylamine, dimethylamine, trimethylamine, and ethylamine, alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine, and multi-rings such as morpholine. Examples include salts of amines such as the formula amine. Among these salts, alkali metal salts and ammonium salts are preferred from the viewpoint of solubility and applicability. The salt form (B
-1) may be polymerized using a salt form, or may be made into a salt after polymerization, or (B
-2) may be used to polymerize and hydrolyze to form a salt. The method for using the crosslinking agent (D) is to add (D) to the polymerization system before, during or after the polymerization reaction, and the temperature varies depending on the type of crosslinking agent, but is usually 10 to 200°C, preferably 20 to 180°C. Then, reaction and crosslinking are carried out according to a conventional method. The viscosity of the graft polymer used in the present invention is usually 2 to 50,000 cps, preferably 5 to 1,000 cs, and more preferably 5 to 500 cs as a 5% aqueous solution. If it is less than 2 cps, the effect of imparting water retention is low;
If it exceeds 50,000 cps, it is difficult to obtain favorable flow characteristics and is therefore undesirable. Grafting efficiency of the backbone polymer of the water-soluble ethylenically unsaturated monomer used in the present invention [(grafted backbone polymer amount (gr)/backbone polymer amount (gr)) x 100
%] can be selected from various values, but usually 1 to 100%,
Preferably 5-100%, more preferably 10-100
%. The grafting efficiency of the backbone polymer may be measured by a solvent extraction method or a fractional precipitation method. The type of solvent used for this separation depends on the monomers used.
It differs depending on the type of (B) and (C) and must be selected appropriately. To explain in more detail how to measure graft efficiency, for example, a dilute aqueous solution (concentration 10% by weight or less) of a graft polymer consisting of polyethylene oxide and sodium acrylate is mixed with about 10 times the amount (by weight) at 20°C or less. The solution containing the precipitated polymer is dropped into methanol with stirring, and the solution containing the precipitated polymer is centrifuged to recover the supernatant, and the remaining precipitated polymer is transferred to a Soxhlet extractor and extracted using methanol. Methanol is distilled off from the extract and the recovered supernatant to obtain unreacted polyether. From this, the grafting efficiency of the backbone polymer is calculated. The paper surface treatment agent of the present invention may be used as a solution or after being dried and ground. Foaming agents, deodorants, fragrances, fillers, dyes, pigments, and the like may be included or used in combination. The paper surface treatment agent of the present invention is added to a paper coating coating mainly containing a pigment and a binder to improve its fluidity and water retention. Examples of pigments include inorganic pigments such as clay, calcium carbonate, titanium oxide, satin white, barium sulfate, talc, and zinc oxide; organic pigments such as plastic pigments (polystyrene described in Japanese Patent Publication No. 46-6524), and combinations thereof. As binders, natural binders, synthetic binders and mixtures thereof can be used. Natural binders include starch, modified starch, and soy protein casein. Synthetic binders include styrene-butadiene latex; acrylic resin emulsions, especially aqueous suspensions of polymers containing small amounts of copolymerized ethylenically unsaturated carboxylic acids; butadiene and acrylonitrile, vinyl acetate and acrylate, butadiene and methyl methacrylate, Copolymers of vinyl chloride and vinylidene chloride, butadiene, methyl methacrylate, vinyl acetate, chlorobrene, homopolymers of vinyl chloride and butyl methacrylate, as well as polymerizable materials at least partially soluble in aqueous media such as polyvinyl alcohol. An example of this material is latex. The amount of the surface treatment agent used for the paper of the present invention (in terms of solid content) is usually 0.001 to 30 parts, preferably 0.01 to 15 parts, and more preferably 0.1 to 5 parts per 100 parts (by weight, same hereinafter) of the pigment. Or, usually 0.001 to 100 parts of binder (solid content equivalent)
50 parts, preferably 0.01 to 30 parts, more preferably
It is 0.1 to 20 parts. If it is less than 0.001 parts per 100 parts of pigment or binder, it will have a fluidity improving effect.
If the water retention effect is insufficient and the amount is more than 30 parts per 100 parts of pigment or more than 50 parts per 100 parts of binder, the water resistance of the coated paper tends to decrease, which is not preferable. The paper coating composition using the paper surface treatment agent of the present invention is usually used in the form of an aqueous dispersion, and if necessary, other additives such as dispersants (sodium pyrophosphate, sodium hexametaphosphate, polyacrylic acid sodium, etc.), antifoaming agents (fatty acid esters,
phosphate esters, polyglycols, silicone compounds, etc.), lubricants (calcium stearate,
Wax, etc.), waterproofing agents (urea resin, melamine resin, glyoxal, etc.), preservatives (formalin, etc.), fluorescent dyes, etc. are added. In addition, water retention agents and fluidity improvers other than those of the present invention, such as CMC,
Although sodium alginate and the like can be used in combination, it is preferable that the amount used is 50% by weight or less of the treatment agent of the present invention. When the amount is more than 50% by weight, the fluidity improving effect decreases. Paper coatings can be applied to paper substrates by known techniques, such as air knife coaters, trailing blade coaters, inverted blade coaters, roll coaters, applicators. After coating, dry and finish with calendering or super calendering if necessary. Coating temperature is usually 10-60℃, drying temperature is usually 90-130℃
℃, the temperature of calender ring and super calender ring is 60-100℃. The treatment agent of the present invention can also be used as a surface sizing agent, and the coating amount can be varied, but usually
0.01~5gr (solid content equivalent)/ ^m2 preferably 0.05~
2gr/m ² , more preferably 0.1 to 1gr/m ² .
Paper that can form a surface size is not particularly limited and can be applied to a wide range of base papers, can be used with or without internal sizing agent treatment or paper strength enhancer treatment, and can be applied to paper made in a wide range of pH ranges. . It can be used by applying an aqueous solution of the treatment agent of the present invention to paper using a size press, doctor knife blade, calendar, etc. in a conventional manner, and then drying it. The paper surface treatment agent of the present invention has the effect of improving the water retention and fluidity of the paper coating paint, preventing scratches and streaks on the coated paper, and providing a smooth coating layer. It has the effect of improving the gloss of white paper and the gloss of printing by providing a coating layer. Furthermore, the paper surface treatment agent of the present invention is of a non-heat-melting type and has the effect of being less likely to stain with a gloss calender. In addition to these, it also has effects as an aqueous improver, paper strength enhancer, and dispersant. The above performance and effects cannot be obtained at all with a polyether or a water-soluble ethylenically unsaturated monomer alone, a salt thereof, or a mixture thereof. The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. In addition, in the following examples, parts mean parts by weight. Examples 1 to 7 Graft polymers [] Polymers having a molecular weight of approximately 3500 were prepared by randomly adding ethylene oxide and propylene oxide to succinic acid in a molar ratio of 9:1 in a reaction apparatus equipped with a stirrer, a thermometer, and a nitrogen blowing tube. 85 parts of ether, 15 parts of methacrylamide, 80 parts of acrylic acid, 30 parts of sodium acrylate, 1 part of sodium styrene sulfonate,
After adding 525 parts of water and stirring with nitrogen, 50℃
Add 35 parts of a 10% aqueous solution of ammonium persulfate and 0.3 parts of a 10% aqueous solution of sodium hydrogen zincate at 50°C.
After reacting for 5 hours, 87.1 parts of a 50% aqueous sodium hydroxide solution was added and neutralized with stirring to obtain a pale yellow aqueous solution of the graft polymer (2). The viscosity (25°C) of the 5% aqueous solution was 43 cps. Graft polymer [) In the same reaction apparatus as in Example 1, 100 parts of polyether with a molecular weight of about 6000, which is obtained by adding ethylene oxide to laurylamine, 45 parts of acrylic acid, 7 parts of ethyl methacrylate, 25 parts of sodium methacrylate, and water.
After adding 600 parts and stirring with nitrogen, add 25 parts of a 10% aqueous solution of ammonium persulfate and 2 parts of a 10% aqueous solution of sodium bisulfite at 30°C, react at 30°C for 10 hours, and then add 50.0g of sodium hydroxide. A 50% aqueous solution was added and stirred at about 70°C to perform neutralization and partial hydrolysis to obtain a pale yellow aqueous solution of the graft polymer (2). The viscosity of the 5% aqueous solution was 63 cps. Graft polymer [) 50.0 parts of adipic acid and tetraethylenepentamine
Molecular weight approximately 2100 obtained by reacting 55.5 parts by a conventional method
A polyether with a molecular weight of approximately 35,000 was synthesized by adding ethylene oxide to the polyamide resin. In the same reactor as in Example 1, 100 parts of this polyether, 25 parts of methacrylic acid, 5 parts of sodium acrylate, 3 parts of hydroxyethyl methacrylate, and 10 parts of ethanol were added.
and 530 parts of water, and after replacing with dissolved nitrogen while stirring,
Add 0.4 parts of a 10% vitamin C aqueous solution and 3.8 parts of a 35% hydrogen peroxide aqueous solution at 40°C, stir and react at 40°C for 6 hours, then add 26.4 parts of a 50% aqueous sodium hydroxide solution and 1.29 parts of calcium hydroxide. was added to neutralize the mixture to obtain a light brown aqueous solution of the graft polymer (2). The viscosity (25°C) of the 5% aqueous solution was 190 cps. Graft polymer [] Dry polyethylene glycol (molecular weight approx.
2000) and 10.5 parts of xylene diisocyanate were reacted in a xylene solution at 120°C, and after xylene was removed, a polyurethane resin with a molecular weight of 63,000 was obtained.
This polyurethane resin 80 was added to the same reactor as in the example.
35 parts of methacrylic acid, 15 parts of sodium acrylate,
Add 5 parts of ethyl methacrylate, 0.1 part of N,N-methylenebisacrylamide and 400 parts of water and dissolve with stirring. After purging with nitrogen, 20 parts of ammonium persulfate and 2 parts of sodium bisulfite were added at 50°C. After reacting with stirring for an hour, 29.3 parts of 50% aqueous sodium hydroxide solution was added and stirred to perform partial neutralization (90% neutralization of methacrylic acid) to obtain a slightly yellowish transparent aqueous solution of the graft polymer (). Ta. The viscosity of the 5% aqueous solution (25%) was 118 cps. In addition, 5 parts (solid content) of the graft polymer () was added to water.
When the solution was dissolved in 45 parts of methanol and added dropwise to 800 parts of methanol with stirring, a white linear solid was precipitated. The solution containing this linear solid was centrifuged at 6000 rpm for 30 minutes to separate the supernatant. The remaining linear solid was transferred to a Soxhlet extractor and extracted with methanol for 8 hours. 500 to 15 mmHg from the extract and the above supernatant, 30
0.52 parts of polyether with methanol distilled off at ~80% was obtained. Also, remove the solids remaining in the Soxhlet extractor by
It was dried at 70°C for 45 hours at mmHg to obtain 4.40 parts of a white solid. The grafting efficiency of the dry polymer was 67.4%. Graft polymer [] In the same reaction apparatus as in Example 1, 95 parts of polyether with a molecular weight of about 7000, which is obtained by randomly adding ethylene oxide and propylene oxide to ethylene glycol at a molar ratio of 80:20, 60 parts of acrylic acid, and sodium methacrylate. Add 45 parts of vitamin C and 600 parts of water, stir and replace with nitrogen, then heat at 50°C with 17 parts of a 10% vitamin C aqueous solution and 15
After adding 1 part of 35% aqueous hydrogen peroxide solution and reacting with stirring at 50°C for 5 hours, 83.3 parts of 50% sodium hydroxide solution was added.
An aqueous solution was added and stirred to neutralize the mixture to obtain a slightly yellow and transparent aqueous solution of the graft polymer (2). The viscosity (25°C) of the 5% aqueous solution was 28 cps. Graft polymer [] In the same reaction apparatus as in Example 1, ethylene oxide and propylene oxide were randomly added to 1,4-butanediol in a molar ratio of 90:10.The molecular weight was approx.
Add 95 parts of 8500 polyether, 70 parts of acrylamide, and 660 parts of water, stir, replace with nitrogen, and then heat at 50°C to 4.3 parts of a 35% hydrogen peroxide aqueous solution and 5 parts of vitamin C 10%.
After adding the aqueous solution and reacting with stirring at 50℃ for 6 hours, 75
A 50% aqueous solution of sodium hydroxide was added and stirred to hydrolyze acrylamide to obtain a pale yellow and cloudy aqueous solution of the graft polymer (2). The viscosity of the 5% aqueous solution was 75 cps. Graft polymer [] In the same reaction apparatus as in Example 1, 50 parts of polyethylene oxide with a molecular weight of about 6000, 30 parts of methyl acrylate,
Add 5 parts of vinyl acetate and 1 part of styrene and add 2.5 parts of ammonium persulfate at 50°C after purging with nitrogen while stirring.
10% aqueous solution and 0.2 parts sodium bisulfite 10%
After adding the aqueous solution and reacting with stirring at 50°C for 6 hours,
After adding 200g of water and dissolving it, 20.9 parts of a 50% aqueous sodium hydroxide solution was added to hydrolyze methyl acrylate and vinyl acetate equivalent to 90% to obtain a slightly yellowish-white aqueous solution of the graft polymer (2). The viscosity of the 5% aqueous solution was 83 cps. The above-mentioned graft polymers of the present invention and comparative examples include a mixture of sodium polyacrylate () (average molecular weight: about 500,000) and polyethylene oxide () (average molecular weight: about 150,000) in a weight ratio of 1:1 (), CMC ( XI) (average molecular weight approximately 30,000), sodium alginate (XII) (1% aqueous solution viscosity 60 cps), and unhydrolyzed product of graft polymer () (
Table 1 shows the physical properties of the coating color and the physical properties of the coated paper using the coating color. To adjust the coating color, add water to a high-speed stirring device.
Add 40 parts of SN-Dispersant 5040 (sodium polyacrylate dispersant) and 0.1 part of sodium hydroxide, and add 55 parts of pre-dispersed clay and 45 parts of light calcium carbonate with stirring. In addition, a color slurry was prepared, and to this was added 12 parts of styrene-butadiene copolymer latex (in terms of solid content), 0.3 parts of the above graft polymer or comparative example material (in terms of solid content), and 1 part of Nopcote C-104 (calcium stearate) (in terms of solid content). (converted) and water were added to make the solid content 67%. Bruckfield viscosity and high shear viscosity (4400 rpm) of the coating color were measured, and water retention was measured using the Warren method. The paper to be processed was coated with a coating color using a bar coater on commercially available high-quality paper with a basis weight of 65gr/m ² (coating amount 20gr/m ² ), and then heated at a temperature of 50℃ and a linear pressure after controlling the humidity.
Created using a super calendar at 80Kg/cm.
The physical properties of the coated paper were measured. As is clear from the first result, the graft polymer of the present invention has excellent properties as a surface treatment agent for paper, imparting good coating properties and improving the gloss and strength of coated paper.

[Table] Test results for coating colors.
(Note 2) 10-point rating: (Good) 10 to 1 (Bad)

Claims (1)

[Scope of Claims] 1. A polymer [polyether (A ); (meth)acrylic acid, (meth)acrylamide,
A water-soluble ethylenically unsaturated monomer (B-1) selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid and vinylsulfonic acid, and ( An ethylenically unsaturated monomer selected from the group consisting of (B-2) an ethylenically unsaturated monomer having a meth)acrylate group
(B); and other ethylenically unsaturated monomers (C) if necessary, (A) is 20 to 80% by weight, the total of (B) and (C) is 20 to 80% by weight, and If less than 25 mol% of (C) in the total of (B) and (C) is graft polymerized and (B-2) is used as (B), the (B-2) unit is further added after graft polymerization. It consists of a graft polymer (G) obtained by hydrolysis, and the viscosity of a 5% by weight aqueous solution is 2 to 50,000 cps,
A paper surface treatment agent that is water-soluble, has a non-thermal melting coating after drying, and is a fluidity improver and water retention agent for paper coatings. 2. The paper surface treatment agent according to claim 1, wherein the graft polymer (G) is a graft polymer crosslinked with a crosslinking agent (D) comprising a polyvalent metal compound capable of forming ionic crosslinks. 3. The paper surface treatment agent according to claim 1 or 2,
A paper surface treatment method using a paper coating paint in which 0.001 to 50 parts by weight of binder is added to 100 parts by weight (in terms of solid content) in the paper coating paint.