JPH0941293A - Surface sizing agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a surface sizing agent exhibiting excellent sizing effect even by adding a small amount by producing a copolymer having narrow molecular weight distribution by radically polymerizing an ethylenic unsaturated monomer using a specific chain transfer agent. SOLUTION: The objective copolymer aqueous solution used as a surface sizing agent containing an α,β-unsaturated carboxylic acid (salt) such as a methacrylic acid copolymer having a weight average moecular weight of 5,000-500,000 and 1.2-3.0 molecular weight distribution is obtained by charging an ethylenic unsaturated monomer such as methacrylic acid or butyl methacrylate in a reaction vessel, radically polymerizing it by using a chain transfer agent such as ethylene glycol-di-2-mercaptoethyl ether of the formula [Q is a multifunctional organic group; A is a 1-8C alkylene; Z is a chain transfer group such as SH; (p) and (q) are independently 0 or 1 and (m) is an integer of 2-100].

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to surface sizing agents. More specifically, the present invention relates to a sizing agent which has an excellent sizing effect even when added in a small amount due to its narrow molecular weight distribution.

[0002]

2. Description of the Related Art Conventionally, as surface sizing agents, α, β-
(Co) polymers of unsaturated carboxylic acids (salts) and the like are known.

[0003]

However, since the (co) polymer of α, β-unsaturated carboxylic acid (salt) obtained by radical polymerization has a wide molecular weight distribution, the molecular weight distribution can be narrowed to further improve the performance. It has been demanded.

[0004]

The present inventors show an excellent size effect even when a small amount of a (co) polymer containing an ethylenically unsaturated monomer having a narrow molecular weight distribution as a structural unit by radical polymerization is added. This has led to the present invention. That is, the present invention is a (co) polymer obtained by polymerizing an ethylenically unsaturated monomer using a radical polymerization initiator and a chain transfer agent for radical polymerization represented by the following general formula (1) ( A surface sizing agent consisting of A). General formula In the formula, Q is a polyvalent organic group, A is an alkylene group having 1 to 8 carbon atoms, Z is a chain transfer group, p and q are 0 or 1, and p and q are not 1 at the same time, and m Is 2 to 100
The integers in [] may be the same or different.

In the present invention, examples of the ethylenically unsaturated monomer are as follows. You may use these 2 or more types together. (A1) α, β-unsaturated carboxylic acid (salt) and its derivatives: (meth) acrylic acid (salt), (anhydrous) maleic acid (salt), maleic acid ester, fumaric acid (salt), fumaric acid ester, Citraconic acid (salt), citraconic acid ester, (meth) acrylic acid (salt), (meth) acrylic acid ester [wherein the alkyl group has 1 to 30 carbon atoms (specifically, methyl (meth) acrylate, butyl (meth)) Acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acriddecyl (Meth) acrylate, tridecyl (meth) acrylate, tetrade Sil (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, eicosyl (meth) acrylate, docosyl (meth) acrylate, etc.], hydroxypolyoxyalkylene ether mono (meth) acrylates, (Meth) acrylamide, etc. (a2) Sulfone group-containing monomer: vinyl sulfonic acid (salt), (meth) allyl sulfonic acid (salt), styrene sulfonic acid (salt), α-methyl styrene sulfonic acid (salt), sulfo Propyl (meth) acrylate, 2-hydroxy-3- (meth) acryloxypropyl sulfonic acid (salt), 2- (meth) acryloylamino-2,2-
Dimethylethanesulfonic acid (salt), 3- (meth) acryloyloxyethanesulfonic acid (salt), 3- (meth) acryloyloxy-2-hydroxypropanesulfonic acid (salt), 2- (meth) acrylamido-2-methyl Propanesulfonic acid (salt), 3- (meth) acrylamide-
2-hydroxypropanesulfonic acid (salt), alkyl (C3-18) allylsulfosuccinic acid (salt), poly (n = 2-30) oxyalkylene (ethylene, propylene, butylene: single, random, or block)
Sulfate ester of mono (meth) acrylate (salt)
[Poly (n = 5 to 15) oxypropylene monomethacrylate sulfate ester (salt) and the like], polyoxyethylene polycyclic phenyl ether sulfate (salt), and other compounds represented by the following general formula. (In the formula, R represents an alkyl group having 1 to 15 carbon atoms, A represents an alkylene group having 2 to 4 carbon atoms, and when n is plural, they may be the same or different, and when different, they may be random or blocks. , X represents an alkali metal, an alkaline earth metal, ammonium, or an amine cation, Ar represents a benzene ring, and n represents an integer of 1 to 50.)

[0006] (In the formula, R represents an alkyl group having 1 to 15 carbon atoms, A represents an alkylene group having 2 to 4 carbon atoms, and when n is plural, they may be the same or different, and when different, they may be random or blocks. , X represents an alkali metal, an alkaline earth metal, ammonium, or an amine cation, Ar represents a benzene ring, and n represents an integer of 1 to 50.)

[0007] (In the formula, R'represents an alkyl group having 1 to 15 carbon atoms which may be substituted with a fluorine atom, and X represents an alkali metal, an alkaline earth metal, ammonium or an amine cation.) (A3) Aliphatic Hydrocarbon monomer: ethylene, propylene, isobutylene, diisobutylene, isoprene, butadiene, etc. (a4) Styrenes: styrene, methylstyrene, vinyltoluene, hydroxystyrene, chlorostyrene, etc. (a5) Unsaturated nitriles: acrylonitrile, metha Acrylonitrile and the like (a6) Fluorine-containing vinyl monomer: perfluorooctylethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, etc. (a7) Nitrogen-containing vinyl monomer: dimethylaminoethyl (meth) acrylate, diethylaminoethyl (Meta)
Acrylate, morpholinoethyl (meth) acrylate, dimethylaminoethyl chloride (meth) acrylate,
Diethylaminoethyl (meth) acrylate etc. (a8) Other monomers: vinyl-modified silicon, vinyl acetate, vinyl chloride, vinylidene chloride, etc.

The (co) polymer (A) has a constitutional unit of
It is preferable to contain an α, β-unsaturated carboxylic acid (salt), and the content thereof is usually 2 with respect to the total weight of the monomers.
It is 0 to 80%, preferably 30 to 70%.

In the general formula (1), Q is a residue obtained by removing OH from polyhydric alcohol or polyhydric phenol,
Examples thereof include a residue obtained by removing COOH from a polycarboxylic acid. As the polyhydric alcohol, alkylene glycol having 2 to 8 carbon atoms (ethylene glycol, propylene glycol, 1,3- and 1,4-butanediol, 1,6
-Hexanediol, neopentyl glycol, etc.),
Dihydric alcohols such as diols having a cyclic group and having 5 to 10 carbon atoms; 3 carbon atoms such as glycerin, trimethylolpropane, trimethylolethane and hexanetriol
~ 12 trihydric alcohol; 4 to 20 carbon atoms such as pentaerythritol, methylglycoside, diglycerin, etc.
Alcohols having a higher number of functional groups, such as pentitols (adnitol, arabitol, xylitol, etc.), hexitols (sorbitol, mannitol, iditol, taritol, dulcitol, etc.), sugars [sucrose, monosaccharides (glucose, mannose, etc.). , Fructose, sorbose, etc.), oligosaccharides (crehalose, lactose, raffinose, etc.)]; glucosides [eg polyols (glycol,
Glucosides of glycerin, trimethylolpropane, alkanepolyols such as hexanetriol); polyalkanepolyols [eg polyglycerin such as triglycerin, tetraglycerin]; polypentaerythritol (dipentaerythritol, tripentaerythritol, etc.); cycloalkanepolyols [Tetrakis (hydroxymethyl) cyclohexanol etc.] and the like can be mentioned. Further, polyvinyl alcohol having a degree of polymerization of up to 100 can be used.

Further, di- and triethanolamine; alkylamines having 2 to 20 carbon atoms, 2 to 6 carbon atoms
Alkylenediamines such as ethylenediamine, propylenediamine, hexamethylenediamine, polyalkylenepolyamines such as aliphatic amines such as diethylenetriamine, triethylenetetramine, aniline, phenylenediamine, diaminotoluene, xylylenediamine, methylenedianiline, diphenyletherdiamine, etc. Examples thereof include alicyclic amines such as group amines, isophoronediamine, cyclohexylenediamine, and dicyclohexylmethanediamine, and alkylene oxide adducts such as aminoethylpiperazine.

Examples of polyhydric phenols include monocyclic polyhydric phenols such as pyrogallol, hydroquinone and phloroglucin; bisphenols such as bisphenol A and bisphenol sulfone; condensates of phenol and formaldehyde (novolak) and polyphenols.

As the polyvalent carboxylic acid, divalent carboxylic acid [(1) aliphatic dicarboxylic acid having 2 to 20 carbon atoms (maleic acid, fumaric acid, succinic acid, adipic acid, sebacic acid, malonic acid, azelaic acid, Mesaconic acid, citraconic acid, glutaconic acid, etc.); (2) Alicyclic dicarboxylic acid having 8 to 20 carbon atoms (cyclohexanedicarboxylic acid, methylmedic acid, etc.); (3) Aromatic dicarboxylic acid having 8 to 20 carbon atoms (phthalate) Acid, isophthalic acid, terephthalic acid, toluenedicarboxylic acid, naphthalenedicarboxylic acid, etc.);
(4) Alkyl or alkenyl succinic acid having a hydrocarbon group having 4 to 35 carbon atoms in the side chain (isododecenyl succinic acid, n-dodecenyl succinic acid, etc.), trivalent or higher carboxylic acids [(1) carbon number 7 to 20 aliphatic polycarboxylic acids (1,2,4-butanetricarboxylic acid, 1,2,5
-Hexanetricarboxylic acid, 1,3-dicarboxylic acid-
2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, etc.); (2) carbon number 9-20
Alicyclic polycarboxylic acids (e.g., 1,2,4-cyclohexanetricarboxylic acid); (3) aromatic polycarboxylic acids having 9 to 20 carbon atoms (1,2,4-benzenetricarboxylic acid, 1,2,5 -Benzenetricarboxylic acid, 2,5,7
-Naphthalene tricarboxylic acid and 1,2,4-naphthalene tricarboxylic acid, pyromellitic acid, benzophenone tetracarboxylic acid, etc.)] and the like. Further, an unsaturated polycarboxylic acid polymer having a degree of polymerization of up to 100 can be mentioned.

In the general formula (1), Z is SH,
SR, SSR, CX ₃ (R is an alkyl, aryl, aralkyl, alkoxy, aryloxy or cycloalkyl group having 1 to 20 carbon atoms, which may be substituted with a halogen atom, an alkyl group, a cyano group or a nitro group. Is a chlorine atom, a bromine atom.) And the like. Of these, SH is preferred.

In the general formula (1), p is 0 when Q is a residue of polyhydric alcohol or polyhydric phenol, and p is 1 when Q is a polyhydric carboxylic acid residue. In the general formula (1), m is preferably 2-8. It is also preferable that p and q are 0 at the same time.

The chain transfer agent represented by the general formula (1) is Z
When is SH, it can be manufactured by the following method, for example. Chain Transfer Agent 1 (when p is 0 and q is 0) The alkylene glycol ether of a polyhydric alcohol is chlorinated at its terminal with thionyl chloride or the like, and then reacted with alkali hydrosulfide. Further, the ω-mercapto-alkyl alcohol and the polyhydric alcohol are etherified. Specific chain transfer agents include ethylene glycol-di-2-mercaptoethyl ether, trimethylolpropane-tri-2-mercaptoethyl ether, pentaerythritol-tetra-2-mercaptoethyl ether and the like.

Chain Transfer Agent 2 (when p is 1 and q is 0) The ω-mercapto-alkyl alcohol and the polycarboxylic acid are esterified. Specific chain transfer agents include maleic acid-di-2-mercaptoethyl ester, fumaric acid-di-2-mercaptoethyl ester, adipic acid-di-2-mercaptoethyl ester, terephthalic acid-di-
2-mercaptoethyl ester and the like can be mentioned.

In the production of the above compound, for example, it is possible to co-add a cyclic ether and a cyclic lactone,
When co-adding, either random co-adding or block co-adding may be used. Examples of cyclic ethers include ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, and styrene oxide, examples of cyclic thioethers include episulfide, and examples of cyclic imines include ethyleneimine. These may be co-added, and when co-added, either random co-addition or block co-addition may be performed. Of these, preferred are cyclic ethers, and more preferred are ethylene oxide, propylene oxide and mixtures thereof. Examples of the cyclic lactone include ε-caprolactone and δ-valerolactone, and examples of the cyclic lactam include ε-caprolactam. These may be co-added, and when co-added, either random co-addition or block co-addition may be performed.

As long as the above conditions are satisfied, the structure of the polymer can be arbitrarily selected depending on the properties of the polymer to be obtained. For example, in the case of compound 1 above, the cyclic ether added is preferably ethylene oxide.

The amount of the chain transfer agent used in the present invention is usually 0.01 to 20% by weight, preferably 0.1 to 10%, particularly preferably 0.1 to 5%, based on the monomers.

Known initiators can be used for the polymerization, and examples thereof include water-soluble azo initiators (azobisamidinopropane (salt), azobiscyanovaleric acid (salt), etc.) and oil-soluble azo. Initiators (azobiscyanovaleronitrile, azobisisobutyronitrile, azobiscyclohexanecarbonitrile, etc.), water-soluble peroxides (hydrogen peroxide, peracetic acid, etc.), oil-soluble peroxides (benzoyl peroxide, cumene) Hydroxy peroxide, etc.), inorganic peroxides (ammonium persulfate, sodium persulfate, etc.) and the like. A redox initiator system may be formed with a peroxide and a reducing agent as described above, and examples of the reducing agent include bisulfite (sodium bisulfite, potassium bisulfite,
Ammonium bisulfite, etc.), tertiary amines (dimethylaminobenzoic acid (salt), dimethylaminoethanol, etc.), amine complexes of transition metal salts (pentamethylenehexamine complex of cobalt (III) chloride, diethylenetriamine complex of copper (II) chloride) Etc.) etc. Further, an azo initiator, a peroxide initiator, or a redox initiator may be appropriately used in combination. The amount of the polymerization initiator is usually 0.01 to 10% by weight, preferably 0.05 to 5% by weight, based on the radically polymerizable monomer.

In the method for producing the polymer of the present invention, the polymerization method may be any of solution polymerization, emulsion polymerization, suspension and bulk polymerization. As the solvent in the case of solution polymerization, water,
Alcohols (methanol, ethanol, isopropanol, etc.), ketones (acetone, methyl isobutyl ketone, etc.), ethers (tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, heptane, etc.), aromatic hydrocarbons (toluene, xylene) Etc.), halogenated solvents (ethylene dichloride, etc.) and mixtures thereof.

The polymerization temperature is usually 50 to 300 ° C.,
Preferably it is 100-250 degreeC. For solution polymerization,
Examples of the temperature include a temperature lower than the boiling point of the polymerization solution under normal pressure, a boiling point of the polymerization solution under normal pressure, and a temperature higher than the boiling point of the polymerization solution under pressure. Further, when a dispersion medium, an emulsifier, a dispersant, etc. are used, there is no particular limitation and known ones can be used.

The weight average molecular weight of the polymer obtained by the production method of the present invention is usually 5,000 to 500,000, preferably 10,000 to 300,000. The molecular weight distribution is usually 1.20 to 3.00, preferably 1.20.
2.50. The molecular weight distribution depends on the polymerization system,
Compared with the case where the chain transfer agent of the present invention is not used, it becomes much narrower. Here, the molecular weight distribution is (weight average molecular weight /
Number average molecular weight)

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to examples, but the present invention is not limited to these examples. Parts in the examples are parts by weight. The method for measuring the number average molecular weight and the molecular weight distribution by GPC is as follows. Type: Waters600 (Japan Waters
Limited) Column: TSK gel G5000pwXL (manufactured by Tosoh) TSK gel G3000pwXL (manufactured by Tosoh) Column temperature: 40 ° C Detector: RI Solvent: 0.5% sodium acetate / water / methanol (volume ratio 70/30) Sample concentration : 0.25% by weight Injection volume: 200 μl Standard: Polyoxyethylene glycol

[0025]

【Example】

(Production of Chain Transfer Agent) Production Example 1 150 parts of triethylene glycol was charged into a reaction vessel,
With stirring, 262 parts of thionyl chloride was added dropwise at 80 ° C. over 2 hours. After maintaining the same temperature for 1 hour, 500 parts of a 30% sodium hydrosulfide aqueous solution was added dropwise over 3 hours.
After holding at the same temperature for 1 hour, the temperature was returned to room temperature, liquid separation was performed, and ethylene glycol-di-2-mercaptoethyl ether 18
0 parts were obtained. This is designated as chain transfer agent A.

Production Example 2 Isophthalic acid and 2-mercaptoethanol were reacted,
Isophthalic acid-di-2-mercaptoethanol ester was obtained. This is designated as chain transfer agent B.

Example 1 260 parts of isopropyl alcohol and 5 parts of water were placed in a pressure resistant reactor.
50 parts were charged, the atmosphere was replaced with nitrogen, the vessel was sealed, and the temperature was raised to 100 ° C. With stirring, a uniform mixture of 170 parts of methacrylic acid, 120 parts of butyl methacrylate and 20 parts of chain transfer agent A, and 45 parts of a 4% sodium persulfate aqueous solution were simultaneously added dropwise from separate containers over 4 hours. After holding at the same temperature for 1 hour, it was neutralized with 15 parts of a 48% aqueous sodium hydroxide solution. Then, the isopropyl alcohol was distilled off and further neutralized with an aqueous 28% ammonia solution to obtain 1,000 parts of a 30% aqueous solution of a methacrylic acid salt copolymer. The weight average molecular weight was 100,000 and the molecular weight distribution was 1.8.

Comparative Example 1 A 30% aqueous solution of a methacrylic acid copolymer was prepared in the same manner as in Example 1 except that the chain transfer agent A was not used.
0 parts were obtained. The weight average molecular weight was 110,000 and the molecular weight distribution was 4.2.

Example 2 A pressure resistant reactor was charged with 320 parts of ethylene dichloride, 95 parts of maleic anhydride and 20 parts of chain transfer agent B, and the temperature was raised to 80 ° C. after nitrogen substitution. With stirring, a mixture of 27 parts of butyl acrylate and 90 parts of styrene and 20 parts of a 2,2′-azobisisobutyronitrile 10% ethylene dichloride solution were added dropwise from separate containers simultaneously over 3 hours for polymerization. . After holding at the same temperature for 1 hour, a mixture of 40 parts of 2-ethylhexyl alcohol and 30 parts of butyl cellosolve was added for esterification. After neutralizing with 6 parts of 48% aqueous sodium hydroxide solution, the ethylene dichloride was distilled off,
Further, 140 parts of 28% aqueous ammonia solution was added, and a 30% aqueous solution of maleic acid half-ester salt copolymer salt was added to 1,000.
Got a part. The weight average molecular weight was 30,000 and the molecular weight distribution was 1.5.

Comparative Example 2 1,000 parts of a 30% aqueous solution of maleic acid half-ester salt copolymer was obtained in the same manner as in Example 2 except that the chain transfer agent B was not used. The weight average molecular weight is 40,000,
The molecular weight distribution was 3.2.

Comparative Example 3 A 30% aqueous solution of a maleic acid half-ester salt copolymer was obtained in the same manner as in Example 2 except that 10 parts of lauryl mercaptan was used as a chain transfer agent. The weight average molecular weight was 20,000 and the molecular weight distribution was 3.8.

(Evaluation) Examples 1 and 2 and Comparative Examples 1 to 3
Table 1 shows the results of evaluation of the size effect using the 30% aqueous solution of the copolymer obtained in (1). The evaluation conditions are as follows. (1) Base paper Pulp L-BKP 100% Filler Talc (12% ash in paper) pH 4.9 (hot water extraction method) Stekihit sizing degree 2 seconds (2) Surface sizing device Lab size press combined drug Oxidized starch (1) 0.8 g / m ² ,
Solid content) Drying rotary auto dryer, 105
℃, 60 seconds

[0033]

[Table 1] Steckigt sizing degree (seconds) Cobb sizing degree (g / m ² ) Coating amount (g / m ² ) 0.01 0.03 0.01 0.03 --------------- ----------------------- Example 1 27 39 14 13 Example 2 26 38 15 13 Comparative Example 1 22 26 20 19 Comparative Example 2 20 25 21 19 Comparative Example 3 18 22 25 22 The coating amount is based on the solid content (copolymer salt).

As shown in Table 1, the sizing agent of the present invention has a high sizing effect.

[0035]

Since the sizing agent of the present invention has a narrow molecular weight distribution, it has an excellent sizing effect even when added in a small amount.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nao Yamauchi 1-11, Hitotsubashi-honcho, Higashiyama-ku, Kyoto Sanyo Chemical Industry Co., Ltd. Kasei Industry Co., Ltd.

Claims (6)

[Claims] 1. A (co) polymer (obtained by polymerizing an ethylenically unsaturated monomer using a radical polymerization initiator and a chain transfer agent for radical polymerization represented by the following general formula (1) ( A surface sizing agent comprising A). General formula In the formula, Q is a polyvalent organic group, A is an alkylene group having 1 to 8 carbon atoms, Z is a chain transfer group, p and q are 0 or 1, and p and q are not 1 at the same time, and m Is 2 to 100
The integers in [] may be the same or different. 2. The sizing agent according to claim 1, wherein Z is SH in the general formula (1). 3. The sizing agent according to claim 1, wherein p and q are 0 in the general formula (1). 4. The sizing agent according to claim 1, wherein the (co) polymer (A) contains an α, β-unsaturated carboxylic acid (salt) as a constituent unit. 5. The (co) polymer (A) has a weight average molecular weight of 5,000 to 500,000 and a molecular weight distribution of 1.
The size of any one of claims 1 to 4, which is 2 to 3.0. 6. The sizing agent according to claim 1, wherein the amount of the chain transfer agent is 0.01 to 20% by weight based on the total amount of the monomers.