JP2006176934A - Additive for papermaking, paper and method for producing paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an additive for papermaking exhibiting excellent effects on enhancement of paper strength, to provide paper and to provide a method for producing the paper. <P>SOLUTION: A means for solving the problems is the additive for papermaking characterized as follows. An acrylamide or a methacrylamide polymer prepared by polymerizing (a) (meth)acrylamide with (b) a vinyl monomer represented by formula (1): CH<SB>2</SB>=CH-CO-NH-CH<SB>2</SB>-CH<SB>2</SB>OH and (c) an ionic vinyl monomer as essential components is contained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a papermaking additive, paper, and a method for producing paper, and more particularly to a papermaking additive, paper, and a method for producing paper that can exhibit an excellent paper strength enhancing effect.

  Conventionally, in the papermaking process, various papermaking additives have been used in order to improve productivity accompanying the increase in the speed of the paper machine or to improve paper quality. In particular, the paper strength enhancer is an important chemical for improving the paper quality and productivity, and the range of use thereof is further widened and the improvement of the chemical is progressing.

  Polyacrylamide copolymers are widely used as paper strength enhancers, and are classified into anionic, cationic, and amphoteric copolymers from the viewpoint of ionicity. First, in the 1960s, an anionic polyacrylamide copolymer was used in combination with a sulfuric acid band. Subsequently, in the 1970s and 80s, for the purpose of improving drainage and yield, a Mannich modified acrylamide polymer into which cationic property was introduced and a Hoffman modified acrylamide polymer were used. However, these modified acrylamide polymers have poor product stability, and the Mannich modified acrylamide polymer has a problem of containing formalin in the product.

  Subsequently, since the 1980s, amphoteric polyacrylamide copolymers obtained by copolymerizing anionic and cationic vinyl compounds with acrylamide have been used (see Patent Document 1). This amphoteric polyacrylamide copolymer is used alone or in combination with an anionic polyacrylamide copolymer. The amphoteric polyacrylamide copolymer has been produced by adding a polymerization initiator to a monomer solution at a predetermined temperature and performing polymerization.

JP-A-60-94697

  Various paper strength enhancing agents that exhibit a paper strength enhancing effect have been proposed so far. For example, “a paper strength enhancer containing a polymer containing hydroxyethyl (meth) acrylamide as a constituent unit, wherein the polymer is composed of hydroxyethyl (meth) acrylamide and another copolymerizable vinyl monomer. The paper strength enhancer according to claim 1, which is a copolymer, has been proposed (see Patent Document 2).

JP 2003-166193 A

  However, in the invention described in Patent Document 2, “Other copolymerizable vinyl monomers include methyl acrylate, butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, long chain aliphatic acrylate, allyl acrylate. Cyclohexyl acrylate, isobornyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylacrylamide, diethylacrylamide, dimethylaminopropylacrylamide, diacetone acrylamide, acryloylmorpholine, etc. In addition, a cationic monomer may be used in combination. Cationic monomers include dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylamide. Examples include inorganic salts such as sulfates and hydrochlorides, or quaternary salts with methyl chloride and benzyl chloride, etc. It is also effective to use an anionic monomer in combination. Acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, 2-acrylamido-2-methylpropanesulfonic acid, etc. These vinyl monomers can be used alone or in combination of two or more. (See Patent Document 2), it does not describe that hydroxyethyl (meth) acrylamide is copolymerized with acrylamide.

  As a thermally crosslinkable resin composition that can be used for paper chemicals, fiber treatment agents, etc., “a thermally crosslinkable resin composition that contains a polymer containing hydroxyethyl (meth) acrylamide as a structural unit and can be dehydrated and crosslinked by heating. The thermally crosslinkable resin composition according to claim 1, wherein the polymer is a copolymer of hydroxyethyl (meth) acrylamide and another copolymerizable vinyl monomer. (See Patent Document 3).

JP 2003-165812 A

  However, in the invention described in Patent Document 3, “as other copolymerizable vinyl monomers, methyl acrylate, butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, long-chain aliphatic acrylate, allyl acrylate” Cyclohexyl acrylate, isobornyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylacrylamide, diethylacrylamide, dimethylaminopropylacrylamide, diacetone acrylamide, acryloylmorpholine, etc. These vinyl monomers can be used. 1 type or 2 or more types can be used ”(see Patent Document 3). And Ruamido, not been described that perform copolymerization with acrylamide.

  Furthermore, the object of the invention described in Patent Document 3 is to solve the problem of formaldehyde emission associated with thermal crosslinking of N-methylol (meth) acrylamide. It is intended to provide a releasable heat-crosslinkable resin composition. ”(See Patent Document 3), it is not mainly intended to enhance paper strength.

  In addition, “(A) acrylamide and / or methacrylamide, and (B) at least one selected from anionic vinyl monomers and (C) cationic vinyl monomers, (D) a vinyl monomer having a polyalkylene glycol group, necessary (E) a non-vinyl vinyl monomer other than the above and (F) a paper additive containing a copolymer obtained by copolymerizing a crosslinkable vinyl monomer is proposed "(Patent Document 4). reference).

Japanese Patent No. 3109195

  Here, in the invention described in Patent Document 4, “in order to solve this problem, a branched structure is provided by using a crosslinking agent, and the molecular weight is increased while suppressing an increase in viscosity of the resulting copolymer. Attempts have been made to achieve this, but the reactivity of the crosslinking agent is insufficient, it is difficult to introduce a uniform branched structure, and a vinyl monomer having a hydroxyalkyl group is used in addition to the crosslinking agent. However, the effect as a papermaking additive was not yet sufficient (Japanese Patent Laid-Open No. 2-139494) ”(see Patent Document 4). There is a negative description for the combined use of acrylamide and a vinyl monomer having a hydroxyalkyl group.

JP-A-2-139494

  In the invention described in Patent Document 5, only 2-hydroxyacrylate is used as a vinyl monomer having a hydroxyalkyl group.

  An object of the present invention is to provide an additive for papermaking, paper, and a method for producing paper, which can solve such conventional problems and exhibit an excellent paper strength enhancing effect.

As means for solving the problems,
Claim 1 comprises (a) (meth) acrylamide,
(B) a vinyl monomer represented by the following formula (1):
_{CH 2 = CH-CO-NH} -CH 2 -CH 2 OH ··· (1)
And (c) a papermaking additive characterized by containing a (meth) acrylamide polymer formed by polymerizing an ionic vinyl monomer as an essential component,
Claim 2 is the papermaking additive according to claim 1, wherein the (c) ionic vinyl monomer is (d) a cationic vinyl monomer and / or (e) an anionic vinyl monomer.
Claim 3 contains a (meth) acrylamide polymer obtained by further polymerizing a vinyl monomer (f) represented by the following formula (2) as an essential component. An additive for papermaking,

[In the formula (2), R ¹ represents an alkylene group having 1 to 4 carbon atoms, R ^{2 to} R ⁴ represent a hydrogen atom or an alkyl group having 22 or less carbon atoms which may have a substituent (provided that R Except when any two or three of ^{2 to} R ⁴ are hydrogen atoms). X ⁻ represents an anion of an inorganic acid or an organic acid. ]
Claim 4 is a paper characterized by comprising the papermaking additive according to any one of claims 1 to 3,
A fifth aspect of the present invention is a paper manufacturing method characterized in that the papermaking additive according to any one of the first to third aspects and a pulp slurry are mixed and made into paper.

According to the present invention, (a) (meth) acrylamide, (b) a vinyl monomer represented by the following formula (1),
_{CH 2 = CH-CO-NH} -CH 2 -CH 2 OH ··· (1)
And (c) By containing a (meth) acrylamide polymer obtained by polymerizing an ionic vinyl monomer as an essential component, an excellent paper strength enhancing effect can be exhibited.

  According to the present invention, an excellent dry paper strength, that is, an excellent paper strength enhancing effect can be exhibited. As a factor that expresses excellent dry paper strength, (b) the hydroxyl terminal derived from the vinyl monomer in the (meth) acrylamide polymer is dehydrated with cellulose or polymer chains in the pulp slurry when heated during paper production. It is presumed that crosslinking occurs and the additive is more firmly fixed on cellulose.

Hereinafter, the present invention will be described in detail. The paper additive according to the present invention includes (a) (meth) acrylamide, (b) a vinyl monomer represented by the following formula (1),
_{CH 2 = CH-CO-NH} -CH 2 -CH 2 OH ··· (1)
And (c) containing a (meth) acrylamide polymer obtained by polymerization using an ionic vinyl monomer as an essential component, and preferably using a vinyl monomer (f), and adding other monomers as necessary for polymerization. And a (meth) acrylamide polymer.

  (A) (Meth) acrylamide that can be used in the present invention is acrylamide or methacrylamide, and these can be used in a powder or an aqueous solution.

  The vinyl monomer (b) that can be used in the present invention is represented by the following formula (1).

_{CH 2 = CH-CO-NH} -CH 2 -CH 2 OH ··· (1)
The (c) ionic vinyl monomer that can be used in the present invention is (d) a cationic vinyl monomer and / or (e) an anionic vinyl monomer.

  Examples of the cationic vinyl monomer include a vinyl monomer having a primary amino group, a vinyl monomer having a secondary amino group, a vinyl monomer having a tertiary amino group, and a vinyl monomer having a quaternary ammonium salt. .

  Examples of the vinyl monomer having a primary amino group include allylamine, methallylamine, and salts thereof. These salts include inorganic acid salts such as hydrochloride and sulfate, and organic acid salts such as formate and acetate.

  Examples of the vinyl monomer having a secondary amino group include diallylamine, dimethallylamine, and salts thereof. These salts include inorganic acid salts such as hydrochloride and sulfate, and organic acid salts such as formate and acetate.

  Further, as the vinyl monomer having a secondary amino group, vinyl monomers having the primary amino group such as allylamine and methallylamine, and alkyl halides such as methyl chloride and methyl bromide, benzyl chloride, and benzyl bromide are used. Examples thereof include monomers converted into secondary amine acid salts by reaction with aralkyl halides, dimethyl sulfate, dialkyl sulfates such as diethyl sulfate, epichlorohydrin and the like.

  Examples of the vinyl monomer having a tertiary amino group include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, dimethylaminopropyl acrylate, dimethylaminopropyl methacrylate, diethylaminopropyl acrylate, and diethylaminopropyl methacrylate. And dialkylaminoalkyl (meth) acrylamides such as dialkylaminoalkyl (meth) acrylates, dimethylaminopropyl acrylamide, dimethylaminopropyl methacrylamide, diethylaminopropyl acrylamide, and diethylaminopropyl methacrylamide, and salts thereof. it can. These salts include inorganic acid salts such as hydrochloride and sulfate, and organic acid salts such as formate and acetate.

  Further, as the vinyl monomer having a tertiary amino group, vinyl monomers having the secondary amino group such as diallylamine and dimethallylamine, and alkyl halides such as methyl chloride and methyl bromide, aralkyl such as benzyl chloride and benzyl bromide. Examples thereof include monomers converted into acid salts of tertiary amines by reaction with any one of halides, alkyl sulfates such as dimethyl sulfate and diethyl sulfate, and epichlorohydrin.

  Examples of the vinyl monomer having a quaternary ammonium salt include diallyldimethylammonium chloride, dimethallyldimethylammonium chloride, diallyldiethylammonium chloride, and diethyldimethallylammonium chloride.

  Examples of the vinyl monomer having a quaternary ammonium salt include a vinyl monomer obtained by reacting the vinyl monomer having a tertiary amino group with a quaternizing agent. Examples of the quaternizing agent include alkyl halides such as methyl chloride and methyl bromide, aralkyl halides such as benzyl chloride and benzyl bromide, alkyl sulfates such as dimethyl sulfate and diethyl sulfate, epichlorohydrin, 3-chloro- Examples include 2-hydroxypropyltrimethylammonium chloride and glycidyltrialkylammonium chloride.

  Specifically, acryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, acryloyloxyethyldimethylbenzylammonium chloride, methacryloyloxyethyldimethylbenzylammonium chloride, acryloyloxypropyldimethylbenzylammonium chloride, and methacryloyloxypropyldimethylbenzylammonium chloride Examples include chloride.

  These vinyl monomers having a primary amino group, a secondary amino group, a tertiary amino group, or a quaternary ammonium salt may be used alone or in combination of two or more.

  (E) As an anionic vinyl monomer, a carboxyl group-containing monomer (which means a polymerizable vinyl monomer containing a carboxyl group), a sulfonic acid group-containing monomer (which contains a sulfonic acid group) And a phosphoric acid group-containing monomer (this means a polymerizable vinyl monomer containing a phosphoric acid group).

  Examples of the carboxyl group-containing monomer include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, cinnamic acid, and crotonic acid, glyoxylic acid such as 2-acrylamide glycolic acid, and 2-methacrylamide glycolic acid, and fumaric acid. Unsaturated dicarboxylic acids such as acid, maleic acid, itaconic acid, citraconic acid and muconic acid, aconitic acid, 3-butene-1,2,3-tricarboxylic acid, and 4-pentene-1,2,4-tricarboxylic acid Unsaturated tricarboxylic acids such as 1-pentene-1,1,4,4-tetracarboxylic acid, 4-pentene-1,2,3,4-tetracarboxylic acid, and 3-hexene-1,1,6, Examples thereof include unsaturated tetracarboxylic acids such as 6-tetracarboxylic acid.

  Examples of the sulfonic acid group-containing monomer include vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, and 2-acrylamido-2-methylpropane sulfonic acid.

  Examples of the phosphoric acid group-containing monomer include vinylphosphonic acid and 1-phenylvinylphosphonic acid.

  Also, salts of carboxyl group-containing monomers, sulfonic acid group-containing monomers, and phosphoric acid group-containing monomers can be used. Examples of the carboxyl group-containing monomer, the sulfonic acid group-containing monomer, or the salt of the phosphoric acid group-containing monomer include alkali metal salts, alkaline earth metal salts, and ammonium salts.

  These may be used alone or in combination of two or more.

  Among the anionic monomers, a suitable anionic monomer is an unsaturated dicarboxylic acid, more preferably itaconic acid.

  It is preferable to use a vinyl monomer (f) represented by the following formula (2). According to this, by further polymerizing the vinyl monomer represented by the following formula (2) as an essential component, it is possible to further improve the dry paper strength of the produced paper. As a factor for the improvement of the dry paper strength, the presence of a vinyl monomer represented by the following formula (2) having a cation moiety at the end of the polymer molecular chain causes the additive to be, for example, anionic cellulose constituting a pulp slurry. Presumably because it contributes to adsorption to the surface.

In formula (2), R ¹ represents an alkylene group having 1 to 4 carbon atoms, R ^{2 to} R ⁴ represent a hydrogen atom or an alkyl group having 22 or less carbon atoms which may have a substituent (provided that R ² any two or three kinds of to R ⁴ excluding a case where the hydrogen atom.). X ⁻ represents an anion of an inorganic acid or an organic acid.

R ¹ is an alkylene group having 1 to 4 carbon atoms, specifically, a methylene group (—CH ₂ —), an ethylene group (—CH ₂ CH ₂ —), a propylene group (—CH ₂ CH ₂ CH ₂ —). ) And a butylene group (—CH ₂ CH ₂ CH ₂ CH ₂ —), and a methylene group is preferred. R ^{2 to} R ⁴ are each a hydrogen atom or an alkyl group having 22 or less carbon atoms which may have a substituent (except when any two or three of R ^{2 to} R ⁴ are hydrogen atoms). , Preferably an alkyl group having 22 or less carbon atoms, a hydroxyalkyl group, an alkylamine group, an alkyl ether group, an alkyl ester group, an alkylamide group, an aryl group, or any two of R ^{2 to} R ⁴ bonded together to form a cyclic structure It is the group that became. Specifically, R ^{2 to} R ⁴ are a methyl group, an ethyl group, a butyl group, a stearyl group, a hydroxyethyl group, and a benzyl group, which may be the same substituent or a combination of different substituents. It may be. Specific examples of the cyclic structure include a morpholine skeleton structure composed of a nitrogen atom, R ³ , and R ⁴ . Also any one of R ² to R ^4, two or three types is a hydroxyethyl group, and more preferably remains R ² to R ⁴ is a hydrogen atom or a methyl group.

X ⁻ is an anion in inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, and nitric acid, or organic acids such as carboxylic acids such as formic acid, acetic acid, oxalic acid, and propionic acid, and Cl ^{-, Br} -, I ^- is preferably, Cl ^- is more preferable.

  Examples of the vinyl monomer (f) represented by the formula (2) include 2-propene-1-aminium, N, N, N, 2-tetramethyl, chloride, 2-propene-1-aminium, N, N. -Diethyl-2-methyl, hydrochloride, 2-propene-1-aminium, N, N, N-triethyl-2-methyl, chloride, 2-propene-1-aminium, N, N, N-tributyl-2- Methyl, chloride, 2-propene-1-aminium, N, N, 2-trimethyl-N-octadecyl, chloride, benzenemethanaminium, N, N-dimethyl-N- (2-methyl-2-propenyl), chloride N-methyl-N- (2-methyl-2-propenyl) morpholinium chloride, 2-propen-1-aminium, N-hydroxyeth -N, N, 2-trimethyl, chloride, 2-propene-1-aminium, N, N-dihydroxyethyl-N, 2-dimethyl, chloride, 2-propene-1-aminium, N-hydroxyethyl-N, 2 -Dimethyl and hydrochloride can be mentioned.

  As another monomer that can be used in the present invention, (g) the crosslinkable monomer and the crosslinkable compound include a monomer having a plurality of vinyl groups, N-substituted (meth) acrylamide, a vinyl group, and a chain transfer point. Examples thereof include a monomer having a crosslinking action, a silicon-based monomer, a water-soluble aziridinyl compound, and a water-soluble polyfunctional epoxy compound. These may be used alone or in combination of two or more.

  Examples of the monomer having a plurality of vinyl groups include trifunctional vinyl monomers, tetrafunctional vinyl monomers and the like in addition to bifunctional monomers such as di (meth) acrylates, bis (meth) acrylamides, and divinyl esters. Can be mentioned.

  Examples of the di (meth) acrylates include ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, propylene glycol diacrylate, propylene glycol diacrylate. A methacrylate, glycerol diacrylate, glycerol dimethacrylate, etc. can be mentioned, These may be used individually by 1 type and may use 2 or more types together.

  Examples of the bis (meth) acrylamides include N, N-methylenebisacrylamide, N, N-methylenebismethacrylamide, ethylenebisacrylamide, ethylenebismethacrylamide, hexamethylenebisacrylamide, hexamethylenebismethacrylamide, N, N-bisacrylamide acetic acid, N, N-bisacrylamide methyl acetate, N, N-benzylidenebisacrylamide, N, N-bis (acrylamidomethylene) urea and the like can be mentioned, and these may be used alone. Two or more kinds may be used in combination.

  Examples of the divinyl esters include divinyl adipate, divinyl sebacate, diallyl phthalate, diallyl malate, and diallyl succinate. These may be used alone or in combination of two or more. You may use together.

  Examples of other bifunctional monomers include allyl acrylate, allyl methacrylate, divinylbenzene, and diisopropenylbenzene. These may be used alone or in combination of two or more. May be.

  Examples of the trifunctional vinyl monomer include triacryl formal, triallyl isocyanurate, N, N-diallylacrylamide, N, N-diallylmethacrylamide, triallylamine, and triallyl pyromellitate. These may be used alone or in combination of two or more.

  Examples of the tetrafunctional vinyl monomer include tetramethylolmethane tetraacrylate, tetraallyl pyromellitate, N, N, N ′, N′-tetraallyl-1,4-diaminobutane, tetraallylamine (salt), and tetra An allyloxyethane etc. can be mentioned, These may be used individually by 1 type and may use 2 or more types together.

  Examples of the N-substituted (meth) acrylamide include N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, and N-isopropyl. (Meth) acrylamide, Nt-octyl (meth) acrylamide, etc. can be mentioned.

  Examples of the monomer having a crosslinking action by having a vinyl group and a chain transfer point include N-methylolacrylamide, glycidyl acrylate, and glycidyl methacrylate, and these may be used alone. Two or more kinds may be used in combination.

  Examples of the silicon monomer include 3-acryloyloxymethyltrimethoxysilane, 3-methacryloyloxymethyltrimethoxysilane, 3-acryloyloxypropyldimethoxymethylsilane, 3-methacryloyloxypropyldimethoxymethylsilane, 3 -Acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-acryloyloxypropylmethyldichlorosilane, 3-methacryloyloxypropylmethyldichlorosilane, 3-acryloyloxyoctadecyltriacetoxysilane, 3 -Methacryloyloxyoctadecyltriacetoxysilane, 3-acryloyloxy-2,5-dimethylhexyldiacetoxymethylsilane, 3-methacryloyloxy-2,5-dimethylhex Luzia Seto carboxymethyl silane, and it can be exemplified vinyl dimethylacetoxysilane like, which may be used singly or in combination of two or more.

  Examples of the water-soluble aziridinyl compound include tetramethylolmethane-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-aziridinylpropionate, and 4,4′-bis (ethyleneimine). And carbonylamino) diphenylmethane. These may be used alone or in combination of two or more.

  Examples of the water-soluble polyfunctional epoxy compound include (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, (poly) glycerin diglycidyl ether, and (poly) glycerin triglycidyl ether. These may be used alone or in combination of two or more.

  Further, as one of other monomers that can be used in the present invention, examples of (h) other monomers include nonionic vinyl monomers. Nonionic vinyl monomers include, for example, (meth) acrylic acid esters, (meth) acrylonitrile, styrene, styrene derivatives, vinyl acetate, vinyl propionate, and methyl vinyl ether, and these are used alone. Or two or more of them may be used in combination.

  The amount of each of the components (a) to (h) in each monomer constituting the (meth) acrylamide polymer is determined by using paper additives containing the resulting (meth) acrylamide polymer. In the case of production, it is possible to determine the paper strength such as the internal bond strength and burst strength of paper, and the performance such as the drainage at the time of papermaking, the yield of fine fibers, fillers, and the like.

In terms of paper strength,
(A) (meth) acrylamide, (b) vinyl monomer, and (c) ionic vinyl monomer are essential for the total of 100 mol% of (a) to (h).
(A) (meth) acrylamide is usually 99.89 to 45 mol%, preferably 98.85 to 74 mol%,
(B) The vinyl monomer is usually 0.01 to 10 mol%, preferably 0.1 to 5 mol%,
(C) The ionic vinyl monomer is usually 0.1 to 40 mol%, preferably 1 to 20 mol%,
(F) A vinyl monomer is 0-5 mol% normally, Preferably it is 0.05-1 mol%.
(G) The crosslinkable monomer and the crosslinkable compound are usually 0 to 5 mol%, preferably 0 to 1 mol%,
(H) Other monomers are usually 0 to 5 mol%, preferably 0 to 1 mol%,
It is.

  In addition, the usage-amount of (d) cationic vinyl monomer and (e) anionic vinyl monomer in (c) ionic vinyl monomer is 0.05-20 mol% normally, respectively.

  In carrying out the polymerization in the present invention, a conventionally known polymerization initiator can be used. Specifically, persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate, peroxides such as benzoyl peroxide, hydrogen peroxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, bromine Bromate such as sodium acid, potassium bromate, perborate such as sodium perborate, ammonium perborate, percarbonate such as sodium percarbonate, potassium percarbonate, ammonium percarbonate, sodium perphosphate, Perphosphates such as potassium perphosphate and ammonium perphosphate can be used. In this case, one kind can be used alone, but two or more kinds may be used in combination, and a redox polymerization initiator may be used in combination with a reducing agent. Examples of the reducing agent include sulfites such as sodium sulfite, bisulfites such as sodium bisulfite, organic amines such as N, N, N ′, N′-tetramethylethylenediamine, and reducing sugars such as aldose. it can. Moreover, these reducing agents may be used individually by 1 type, and may be used together 2 or more types. Other than the above, azobisisobutyronitrile, 2,2′-azobis-2-amidinopropane hydrochloride, 2,2′-azobis-2,4′-dimethylvaleronitrile, 4,4′-azobis- Azo polymerization initiators such as 4-cyanovaleric acid and its salts can also be used.

  Moreover, a conventionally well-known chain transfer agent can be used suitably as needed. Conventionally known chain transfer agents include compounds having one or more hydroxyl groups in the molecule, such as oligomers and polymers such as isopropyl alcohol, butanol, ethylene glycol, glycerine alcohols, polyethylene oxide, polyglycerin, glucose, and the like. And saccharides and vitamins such as ascorbic acid and sucrose. Examples of the compound containing one or more mercapto groups in the molecule include butyl mercaptan, mercaptoethanol, thioglycolic acid and its ester, mercaptopropionic acid and its ester, thioglycerin, cysteamine and its salt. be able to. Examples of compounds having one or more carbon-carbon unsaturated bonds in the molecule include (meth) allyl alcohol and its ester derivatives, (meth) allylamine, diallylamine, dimethallylamine and its amide derivatives, triallylamine, Examples include methallylamine, (meth) allylsulfonic acid and salts thereof, allyl sulfides, and allyl mercaptans. Furthermore, mention may be made of hypophosphorous acid.

  The synthesis of the (meth) acrylamide polymer in the present invention is usually performed according to the procedure described in the following (i), (ii), or (iii).

  (I) As batch polymerization, in a predetermined reaction vessel under an inert gas atmosphere such as nitrogen, the monomers (a) to (h) and water as a solvent (an organic solvent may be used in combination) The (meth) acrylamide polymer of the present invention is obtained by charging the chain transfer agent as necessary and adding the polymerization initiator under stirring to initiate polymerization.

  (Ii) As the divided addition polymerization, any one or more of the monomers (a) to (h) are appropriately divided in advance and divided into predetermined reaction vessels in an inert gas atmosphere such as nitrogen. Any one or more of the monomers (a) to (h) and a solvent, for example, water or a mixed solvent of water and an organic solvent, and, if necessary, the chain transfer agent are charged, with stirring, The polymerization initiator is added to start the polymerization, and any one or more of the remaining monomers (a) to (h) are added to the reaction vessel with or without the polymerization initiator. Thus, the (meth) acrylamide polymer of the present invention is obtained.

  (Iii) As dropwise polymerization, under a inert gas atmosphere such as nitrogen, water as a solvent (may be used in combination with an organic solvent) in a predetermined reaction vessel, if necessary, charging the chain transfer agent, Under stirring, a monomer, water as a solvent (an organic solvent may be used in combination) and, if necessary, a solution charged with the chain transfer agent are dropped, and at the same time, the polymerization initiator is added. To initiate polymerization. After completion of the dropwise addition, the (meth) acrylamide polymer of the present invention is obtained by further heating as necessary and polymerizing by this.

  The papermaking additive produced according to the present invention exhibits a paper strength enhancing effect when added to a pulp slurry when producing paper. As pulp raw materials, bleached or unbleached chemical pulp, groundwood pulp, bleached or unbleached pulp such as mechanical pulp and thermomechanical pulp, etc. And waste paper pulp such as deinked waste paper can be used.

  Moreover, in order to express the physical property requested | required of each paper type, the other papermaking additive can also be used together with the papermaking additive manufactured by this invention. Examples of other papermaking additives used in combination include fillers, dyes, rosin sizing agents for acidic papermaking, rosin sizing agents for neutral papermaking, alkyl ketene dimer sizing agents, and alkenyl succinic anhydride sizing agents. Weakly acidic, neutral and alkaline papermaking sizing agents such as specially modified rosin sizing agents, wet paper strength enhancers, yield improvers, drainage improvers, coagulants, bulking agents, paper thickness improvers, and A foaming agent etc. are mentioned. These may be used alone or in combination of two or more. Examples of the filler include clay, talc, titanium oxide, heavy or light calcium carbonate, and white carbon.

  Further, the paper additive of the present invention may contain the (meth) acrylamide polymer synthesized according to the present invention alone, an anionic acrylamide polymer, a Mannich modified acrylamide polymer, a Hoffman modified acrylamide. The polymer may contain a sulfuric acid band and the like. The papermaking additive of the present invention may be used alone or in combination with an anionic acrylamide polymer, a Mannich modified acrylamide polymer, a Hoffman modified acrylamide polymer, a sulfuric acid band and the like.

  The paper of the present invention can be obtained by, for example, paper making using the above-described papermaking additive of the present invention. Examples of the paper obtained include PPC paper, inkjet recording paper, laser printer paper, foam paper, art paper. , Printing information paper such as cast paper, high-quality coated paper, photographic paper, kraft paper, wrapping paper such as pure white roll paper, other notebook paper, book paper, printing paper, western paper such as newspaper, Manila ball, white Examples include paperboard such as balls, chip balls, high-quality white paperboard, liners, core base paper, and paper tube base paper.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to the following Example. % Is based on weight unless otherwise indicated.

Example 1
(Synthesis of (meth) acrylamide polymer in the paper additive of the present invention)
In a 1 liter four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 268.4 g of 50% acrylamide aqueous solution, 4.72 g of 100% dimethylaminoethyl methacrylate, 76% dimethylaminoethyl methacrylate chloride Benzyl quaternized aqueous solution 11.2 g, 100% itaconic acid 5.2 g, 100% N- (2-hydroxyethyl) acrylamide 0.46 g, 75% dimethylhydroxyethyl methallyl ammonium chloride aqueous solution 1.92 g, ion-exchanged water 444 .8 g was charged, and then adjusted to pH 3.0 with 95% aqueous sulfuric acid solution.

  Next, nitrogen gas was introduced into the four-necked flask to remove oxygen in the reaction system. The aqueous monomer solution in the four-necked flask was heated to 60 ° C. Under stirring, 0.23 g of ammonium persulfate was added as a polymerization initiator to initiate polymerization. The temperature was raised to 90 ° C. and kept warm. One hour after the start of the polymerization, 0.23 g of ammonium persulfate was additionally added, and the polymerization was stopped after 2 hours. After cooling, an aqueous polymer solution having a pH of 4.0, a solid content of 20.8%, and a viscosity of 5500 mPa · s (using a Brookfield rotational viscometer at 25 ° C.) was obtained. Table 1 below shows the composition and properties of each component.

(Example 2)
A polymer aqueous solution was obtained in the same manner as in Example 1 except that sodium methallyl sulfonate was used in place of the aqueous dimethylhydroxyethyl methallyl ammonium chloride solution in Example 1. Table 1 below shows the composition and properties of each component.

(Example 3)
In a 1 liter four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 259.6 g of 50% acrylamide aqueous solution, 21.3 g of 76% dimethylaminoethyl acrylate benzyl chloride quaternary compound aqueous solution, 79% dimethylaminoethyl acrylate methyl chloride quaternized aqueous solution 9.8 g, 100% fumaric acid 2.3 g, 80% aqueous acrylic acid solution 3.6 g, 100% N- (2-hydroxyethyl) acrylamide 0.23 g, 100 % N, N, dimethylacrylamide 0.2g, 100% triacryl formal 0.05g, 75% dimethyl hydroxyethyl methallyl ammonium chloride aqueous solution 2.4g, ion-exchange water 469.0g were charged.

  Next, nitrogen gas was introduced into the four-necked flask to remove oxygen in the reaction system. The aqueous monomer solution in the four-necked flask was heated to 60 ° C. Under stirring, 0.23 g of ammonium persulfate was added as a polymerization initiator to initiate polymerization. The temperature was raised to 90 ° C. and kept warm. One hour after the start of the polymerization, 0.23 g of ammonium persulfate was additionally added, and the polymerization was stopped after 2 hours. After cooling, an aqueous polymer solution having a pH of 4.0, a solid content of 20.3%, and a viscosity of 6700 mPa · s (using a Brookfield rotational viscometer at 25 ° C.) was obtained. Table 1 below shows the composition and properties of each component.

Example 4
In Example 3, a polymer aqueous solution was obtained in the same manner as in Example 3 except that part of the dimethylhydroxyethyl methallyl ammonium chloride aqueous solution was replaced with sodium methallyl sulfonate. Table 1 below shows the composition and properties of each component.

(Comparative Example 1)
In Example 2, an aqueous polymer solution was obtained in the same manner as in Example 2 except that N, N, -dimethylacrylamide was used instead of N- (2-hydroxyethyl) acrylamide. Table 1 below shows the composition and properties of each component.

(Comparative Example 2)
In Example 4, an aqueous polymer solution was obtained in the same manner as in Example 4 except that N, N, dimethylacrylamide was used instead of N- (2-hydroxyethyl) acrylamide. Table 1 below shows the composition and properties of each component.

(Evaluation of handmade paper 1)
A 2.0% sulfuric acid band was added to the solid content of pulp to a corrugated waste paper pulp slurry having a pulp concentration of 2.4%, adjusted to 350 using Canadian standard freeness, and then Examples 1-2 Then, 0.4% of the polymer solution obtained in Comparative Example 1 was added.

After stirring the pulp slurry, the pulp concentration was diluted to 0.8% with water having a pH of 6.0, and then papermaking was performed with a Noble and Wood sheet machine to obtain a wet paper. The wet paper was pressed and then dried with a drum dryer at 100 ° C. for 80 seconds to obtain a hand-made paper having a basis weight of 80 g / m ² .

  The obtained handmade paper was conditioned at 23 ° C. and RH 50% for 24 hours, and then subjected to various measurements. The internal bond was measured according to JAPAN TAPPI 18-2, the dry fracture length was measured according to JIS P8113, and the wet fracture length was measured according to JIS P8135. In Comparative Example A, no polymer solution was added when producing handmade paper.

(Evaluation of handmade paper 2)
Add 1.5% sulfuric acid band to the solid content of pulp to hardwood bleached kraft (LBKP) pulp slurry with 2.4% pulp concentration adjusted to 400 Canadian Standard Freeness using a beater, then run 0.5% of the polymer solutions obtained in Examples 3 to 4 and Comparative Example 2 were added.

After stirring the pulp slurry, the pulp concentration was diluted to 0.8% with water having a pH of 5.0, and papermaking was performed with a sheet machine made by Noble and Wood to obtain a wet paper. The wet paper was pressed and then dried with a drum dryer at 100 ° C. for 80 seconds to obtain a hand-made paper having a basis weight of 80 g / m ² .

  The obtained handmade paper was conditioned at 23 ° C. and RH 50% for 24 hours, and then subjected to various measurements. The internal bond was measured according to JAPAN TAPPI 18-2, the dry fracture length was measured according to JIS P8113, and the wet fracture length was measured according to JIS P8135. In Comparative Example B, no polymer solution was added when producing handmade paper.

Claims (5)

(A) (meth) acrylamide,
(B) a vinyl monomer represented by the following formula (1):
_{CH 2 = CH-CO-NH} -CH 2 -CH 2 OH ··· (1)
And (c) an ionic vinyl monomer,
An additive for papermaking, which contains a (meth) acrylamide polymer obtained by polymerizing as an essential component.   The papermaking additive according to claim 1, wherein the (c) ionic vinyl monomer is (d) a cationic vinyl monomer and / or (e) an anionic vinyl monomer. The papermaking additive according to claim 1 or 2, further comprising a (meth) acrylamide polymer obtained by polymerizing a vinyl monomer represented by the following formula (2) as an essential component.

[In the formula (2), R ¹ represents an alkylene group having 1 to 4 carbon atoms, R ^{2 to} R ⁴ represent a hydrogen atom or an alkyl group having 22 or less carbon atoms which may have a substituent (provided that R Except when any two or three of ^{2 to} R ⁴ are hydrogen atoms). X ⁻ represents an anion of an inorganic acid or an organic acid. ]   A paper comprising the paper additive according to any one of claims 1 to 3. A paper manufacturing method comprising mixing the paper additive according to any one of claims 1 to 3 with pulp slurry and making paper.