JP5499237B2 - Bleaching aid for cellulose pulp and method for producing bleached cellulose pulp - Google Patents

Description

  The present invention relates to a cellulose pulp bleaching aid and a method for producing bleached cellulose pulp.

Wood and non-wood (herbaceous) lignocellulosic material is digested with alkali or sulfite, then bleached with oxygen gas or ozone gas, and further with chlorine, hypochlorite, chlorine dioxide, hydrogen peroxide, etc. A method for producing pulp by bleaching is widely known (Non-patent Document 1).
Nonionic surfactants are known as bleaching aids for reducing the amount of bleaching agents such as oxygen, ozone, chlorine, hypochlorite, chlorine dioxide and hydrogen peroxide (Patent Documents). 1).
Paper and Pulp Papermaking Chemistry and Technology, Volume 1 Volume 2, Volume 2, Chugai Industry Research Committee, 1986, pages 373-477 and 640-671 JP-A-9-195191

However, even if a conventional bleaching aid is used, the white color is sufficient due to insufficient decomposition of lignin or due to redeposition of lignin degradation products and resin components to cellulose. There is a problem that pulp having a degree cannot be obtained.
An object of the present invention is to provide a bleaching aid that can achieve a significantly high bleaching efficiency and can easily obtain a pulp having a high whiteness.

The feature of the bleaching aid of the present invention is a bleaching aid used in the bleaching process of cellulose pulp with chlorine dioxide,
Oh Kishikarubon acid, and gist points comprising the organic acid (A) and / or a salt selected either et tricarboxylic acid or tetracarboxylic acid.

  The feature of the method for producing the bleached cellulose pulp of the present invention is summarized in that it includes a bleaching step of adding the bleaching aid to the cellulose pulp slurry to bleach the cellulose pulp.

The bleaching assistant of the present invention can achieve a markedly high bleaching efficiency and can easily obtain a pulp having a high whiteness.
Moreover, the usage-amount of a bleaching agent can be reduced significantly by using the bleaching aid of this invention. Furthermore, the bleaching aid of the present invention has an effect that there is little adverse effect on the environment.

  Moreover, the manufacturing method of the bleached cellulose pulp of this invention can achieve remarkably high bleaching efficiency (reduction rate of the usage-amount of a bleaching agent) by using said bleaching auxiliary agent, and the usage-amount of a bleaching agent is greatly increased. Can be reduced. Furthermore, the production method of the present invention has an effect that there is little adverse effect on the environment.

  Examples of the organic acid (A) include aminocarboxylic acid (A1), oxycarboxylic acid (A2), and carboxylic acid (A3).

  The aminocarboxylic acid (A1) includes aminomonocarboxylic acids and aminopolycarboxylic acids.

  Examples of amino monocarboxylic acids include dihydroxymethyl glycine, dihydroxyethyl glycine, alanine, valine, leucine, and isoleucine.

  Aminopolycarboxylic acids include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid, triethrenetetraminehexaacetic acid, nitrilotriacetic acid and hydroxyiminodiacetic acid, N, N-dicarboxymethylaspartic acid and N, N-dicarboxymethyl -Methyl glycine etc. are mentioned.

  Examples of the oxycarboxylic acid (A2) include oxymonocarboxylic acid and oxypolycarboxylic acid.

  Examples of the oxymonocarboxylic acid include lactic acid, glyceric acid, arabinonic acid, gluconic acid, and galactonic acid.

  Examples of the oxypolycarboxylic acid include malic acid, citric acid, isocitric acid, tartaric acid, arabinal acid, glucaric acid, and galactaric acid.

Examples of the carboxylic acid (A3) include monocarboxylic acids, dicarboxylic acids, tricarboxylic acids, tetracarboxylic acids, and at least pentavalent polycarboxylic acids.
Examples of the monocarboxylic acid include saturated monocarboxylic acid and unsaturated monocarboxylic acid.
As a saturated monocarboxylic acid, a C2-C30 saturated linear monocarboxylic acid, a C4-C30 saturated branched monocarboxylic acid, a C5-C30 saturated cyclic monocarboxylic acid, etc. can be used.

  Examples of saturated linear monocarboxylic acids include acetic acid, n-propionic acid, n-butanoic acid, n-pentanoic acid, n-hexanoic acid, n-heptanoic acid, n-octanoic acid, n-nonanoic acid and n-decanoic acid. N-undecanoic acid, n-dodecanoic acid, n-tridecanoic acid, n-tetradecanoic acid, n-pentadecanoic acid, n-hexadecanoic acid, n-heptadecanoic acid, n-octadecanoic acid, n-nonadecanoic acid, n-eicosanoic acid N-docosanoic acid, n-tetracosanoic acid, n-hexacosanoic acid, n-octacosanoic acid and n-triacontanoic acid.

  Examples of saturated branched monocarboxylic acids include 2-methylpropanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, 2-methylheptanoic acid, 2-ethyloctanoic acid, 2-methylundecanoic acid, 2-ethyltetradecanoic acid, Examples include 2-methylheptadecanoic acid, 2-methyltricosanoic acid, and 2-ethyloctacosanoic acid.

  Examples of saturated cyclic monocarboxylic acids include cyclobutane carboxylic acid, cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, 2-cyclohexyl ethanoic acid, 3-cyclohexyl propanoic acid, 4-cyclohexyl butanoic acid, 6-cyclohexyl hexanoic acid, 8-cyclohexyloctanoic acid, 12-cyclohexyldodecanoic acid, 16-cyclohexyltetradecanoic acid, 18-cyclohexyloctadecanoic acid, 2- (carboxycyclohexyl) -2-cyclohexylpropane, 4- (cyclohexyl) cyclohexanecarboxylic acid and 24-cyclohexyllignoserin An acid etc. are mentioned.

  Examples of unsaturated monocarboxylic acids include aliphatic unsaturated linear monocarboxylic acids having 4 to 22 carbon atoms, aliphatic unsaturated branched monocarboxylic acids having 5 to 30 carbon atoms, and aromatic monocarboxylic acids having 7 to 30 carbon atoms. Etc. can be used.

  Aliphatic unsaturated linear monocarboxylic acids include butenoic acid, pentenoic acid, hexenoic acid, heptenoic acid, octenoic acid, nonenoic acid, decenoic acid, undecenoic acid, dodecenoic acid, tetradecenoic acid, hexadecenoic acid, octadecenoic acid, eicosenoic acid , Docosenoic acid, tetracosenoic acid, linoleic acid, eleostearic acid, linolenic acid, parinaric acid, arachidonic acid, talylic acid, stearolic acid, and behenolic acid.

  Examples of the aliphatic unsaturated branched monocarboxylic acid include 2-methyl-3-butenoic acid, 2-ethyl-5-hexenoic acid, 2-methyl-10-undecenoic acid, 2-ethyl-15-hexadecenoic acid, 2-methyl -22-tricosenoic acid and 2-ethyl-27-octacosenoic acid.

  Examples of aromatic monocarboxylic acids include benzenecarboxylic acid (benzoic acid), phenylethanoic acid, 3-phenylpropanoic acid, 4-phenylbutanoic acid, 5-phenylpentanoic acid, 6-phenylhexanoic acid, 8-phenyloctanoic acid, Examples include 10-phenyldecanoic acid, 12-phenyldodecanoic acid, 18-phenyloctadecanoic acid, 24-phenyltetracosanoic acid, naphthalenecarboxylic acid, 4-phenylbenzenecarboxylic acid, and 2- (carboxyphenyl) -2-phenylpropane. It is done.

Examples of the dicarboxylic acid include saturated dicarboxylic acid and unsaturated dicarboxylic acid.
As saturated dicarboxylic acid, C4-C32 saturated linear dicarboxylic acid, C6-C21 saturated branched dicarboxylic acid, C8-C20 saturated cyclic dicarboxylic acid, etc. can be used.

  Saturated linear dicarboxylic acids include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecane Examples thereof include dicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, 1,24-tetracosanedicarboxylic acid, malic acid, and 1,30-triacontanedicarboxylic acid.

  Examples of the saturated branched dicarboxylic acid include 2-methylpropane-1,3-dicarboxylic acid, 2-methyloctane-1,8-dicarboxylic acid, and 2-methyloctadecane-1,18-dicarboxylic acid.

  Examples of the saturated cyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, dimer acid, 4- (carboxycyclohexyl) cyclohexanecarboxylic acid, and 2,2-bis (carboxycyclohexyl) propane.

  Examples of the unsaturated dicarboxylic acid include aliphatic unsaturated linear dicarboxylic acids having 4 to 30 carbon atoms, aliphatic unsaturated branched dicarboxylic acids having 7 to 21 carbon atoms, and aromatic dicarboxylic acids having 8 to 17 carbon atoms. .

  Examples of the aliphatic unsaturated linear dicarboxylic acid include maleic acid, fumaric acid, 2-hexene-1,6-dicarboxylic acid, 2-octene-1,8-dicarboxylic acid, 2-decene-1,10-dicarboxylic acid, 2-dodecene-1,12-dicarboxylic acid, 2-hexadecene-1,16-dicarboxylic acid, 2-tetracocene-1,24-dicarboxylic acid, 2-triacontene-1,30-dicarboxylic acid and 2,6-octadiene -1,8-dicarboxylic acid and the like.

  Examples of the aliphatic unsaturated branched dicarboxylic acid include 2-methyl-2-butene-1,4-dicarboxylic acid, 2-methyl-2-octene-1,8-dicarboxylic acid and 2-methyl-2-octadecene-1, Examples thereof include 18-dicarboxylic acid.

  Examples of the aromatic dicarboxylic acid include phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, benzylsuccinic acid, 4- (carboxyphenyl) benzenecarboxylic acid, and 2,2-bis (carboxyphenyl) propane.

  Examples of the tricarboxylic acid include aliphatic tricarboxylic acids having 6 to 13 carbon atoms and aromatic tricarboxylic acids having 9 to 13 carbon atoms.

Examples of the aliphatic tricarboxylic acid include aconitic acid {HO ₂ CCH ₂ C (CO ₂ H) ═CHCO ₂ H}, hexanetricarboxylic acid, octenetricarboxylic acid, cyclohexanetricarboxylic acid, and decanetricarboxylic acid.

  Examples of the aromatic tricarboxylic acid include 1,3,5-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, and naphthalenetricarboxylic acid.

  Examples of the tetracarboxylic acid include aliphatic tetracarboxylic acids having 8 to 10 carbon atoms and aromatic tricarboxylic acids having 10 to 16 carbon atoms.

  Examples of the aliphatic tetracarboxylic acid include 1,2,3,4-butanetetracarboxylic acid and 1,2,4,5-cyclohexanetetracarboxylic acid.

  Aromatic tetracarboxylic acids include benzene-1,2,3,4-tetracarboxylic acid, biphenyl-2,3,3 ′, 4′-tetracarboxylic acid and naphthalene-1,8,4,5-tetracarboxylic acid. An acid etc. are mentioned.

  Examples of the at least pentavalent polycarboxylic acid include water-soluble copolymers containing an ethylenically unsaturated carboxylic acid as a structural unit.

  Examples of ethylenically unsaturated carboxylic acids include α, β-unsaturated carboxylic acids {such as acrylic acid and methacrylic acid}, α, β-unsaturated dicarboxylic acids {such as crotonic acid, maleic acid, and itaconic acid}.

  The weight average molecular weight of the water-soluble copolymer is preferably 300 to 15,000, more preferably 500 to 10,000, and particularly preferably 700 to 5,000. When it is within this range, the bleaching efficiency is further improved.

  The weight average molecular weight is a value obtained using gel permeation chromatography (hereinafter abbreviated as GPC) (measurement conditions are as follows, for example).

<GPC measurement conditions>
Model: Waters 510 (manufactured by Japan Waters Limited)
Column: Column in which TSK gel G5000pwXL and TSK gel G3000pwXL (both manufactured by Tosoh Corporation) are connected in series. Column temperature: 40 ° C
Detector: RI
Solvent: 0.5% sodium acetate / water / methanol (volume ratio 70/30)
Flow rate: 1.0 ml / min Sample concentration: 0.25% by weight
Injection volume: 200 μl
Standard: Polyoxyethylene glycol (manufactured by Tosoh Corporation; TSK STANDARD POLYETHYLENE OXIDE)
Data processing device: SC-8010 (manufactured by Tosoh Corporation)

  Of these organic acids, aminocarboxylic acid (A1), oxycarboxylic acid (A2), and at least pentavalent polycarboxylic acid are preferable and more preferable from the viewpoint of bleaching efficiency (reduction rate of the amount of bleach used). Is aminocarboxylic acid (A1) and oxycarboxylic acid (A2), particularly preferably oxycarboxylic acid (A2), most preferably lactic acid, malic acid and citric acid.

  Examples of the salt of the organic acid (A) include ammonia salts, alkylamine (monoethylamine, monobutylamine and triethylamine etc.) salts, alkanolamine (monoethanolamine, diethanolamine and triethanolamine etc.) salts, alkali metals (lithium, sodium and Potassium and the like) and alkaline earth metal (magnesium, calcium and zinc) salts and the like.

  When both the salt of the organic acid (A) and the salt of the organic acid (A) is included, the content weight ratio {organic acid (A) / salt of the organic acid (A)} is preferably 0.1 to 100, Preferably it is 0.2-90, Most preferably, it is 0.5-80.

  In the bleaching aid of the present invention, the water-soluble polymer (B) having a solubility parameter of 14 to 24 and / or HLB of 6 to 18 is further used from the viewpoint of bleaching efficiency (reduction rate of the amount of bleach used). It is preferable that the surfactant (C) is included.

  The solubility parameter (SP value) is a value represented by the square root of the ratio between the heat of molar evaporation and the molar volume, as shown in the following formula (1).

SP value (δ) = (ΔH / V) ^1/2 (1)

In the formula, ΔH represents the heat of vaporization (cal), and V represents the molar volume (cm ³ ).
ΔH and V are the sum of the heat of molar evaporation (Δei) of the atomic group described in “POLYMER ENGINEERING AND FEBRUARY, 1974, Vol. 14, No. 2, ROBERT F. FEDORS. (Pages 151 to 153)” The sum (V) of [Delta] H) and molar volume ([Delta] vi) can be used.

  When the constituent monomer of the water-soluble polymer (B) is one kind, the SP value is the same as the SP value of the constituent monomer. When there are two or more constituent monomers of the water-soluble polymer (B), the SP value is the sum of values obtained by multiplying the SP value of each constituent monomer by the mole fraction.

  The SP value of the water-soluble polymer (B) is 14 to 24, preferably 15 to 23, more preferably 16 to 22, and particularly preferably 17 to 19.5. Within this range, the bleaching efficiency is further improved.

In the present invention, the water-soluble polymer means a polymer having the above SP value. That is, water-soluble means a property that the SP value is in the above range.
The water-soluble polymer (B) includes at least one polymer selected from the group consisting of a water-soluble anionic polymer, a water-soluble nonionic polymer, a water-soluble cationic polymer, and a water-soluble amphoteric polymer.

  The water-soluble anionic polymer may be any water-soluble polymer having at least one anionic group {carboxy group, sulfo group, sulfooxy group, phosphono group, etc.) in one molecule. Anionic non-radical polymers and water-soluble anionic natural polymers are included.

The water-soluble anion radical polymer includes a polymer having the anionic vinyl monomer (b1) as an essential constituent monomer.
Examples of the anionic vinyl monomer (b1) include the following.
(B1-1) Carboxy group-containing vinyl monomer Monocarboxylic acid {unsaturated monocarboxylic acid [(meth) acrylic acid, crotonic acid, cinnamic acid, etc.] and monoalkyl of unsaturated dicarboxylic acid (1 to 8 carbon atoms) Esters [maleic acid monoalkyl esters, fumaric acid monoalkyl esters, itaconic acid monoalkyl esters, etc.]
Dicarboxylic acid {maleic acid, fumaric acid, itaconic acid, citraconic acid, etc.}

(B1-2) Sulfo group-containing vinyl monomer C2-C6 alkene sulfonic acid {vinyl sulfonic acid and (meth) allyl sulfonic acid, etc.}
C6-C12 aromatic vinyl group-containing sulfonic acid {styrene sulfonic acid and α-methylstyrene sulfonic acid, etc.}
Sulfo group-containing (meth) acrylic ester {sulfopropyl (meth) acrylate and 2- (meth) acryloyloxyethanesulfonic acid, etc.}
Sulfo group-containing (meth) acrylamide {2- (meth) acrylamide-2-methylpropanesulfonic acid, etc.}
Vinyl monomer containing sulfo group and hydroxyl group {3- (meth) acrylamide-2-hydroxypropanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid and 3- (meth) acryloyloxy-2-hydroxypropane Sulfonic acid, etc.}
Alkyl (C3-C18) allyl sulfosuccinate {Dodecyl allyl sulfosuccinate etc.}

(B1-3) Sulfooxy group-containing vinyl monomer Poly (degree of polymerization 2 to 30) oxyalkylene (oxyethylene, oxypropylene and / or oxybutylene: any of random and block. The same applies hereinafter) Mono ( (Meth) acrylate sulfate, poly (polymerization degree 2-30) oxyalkylene bisphenol A mono (meth) acrylate sulfate, etc.

(B1-4) Phosphono group-containing vinyl monomer (meth) acryloyloxyalkyl (alkyl having 2 to 6 carbon atoms) phosphoric acid monoester {(meth) acryloyloxyethyl phosphate, etc.}
(Meth) acryloyloxyphosphonic acid {2-acryloyloxyethylphosphonic acid, etc.}

As an anionic vinyl monomer, salt {monovalent metal salt, divalent metal salt, amine salt or ammonium salt, the same shall apply hereinafter. }.
Examples of monovalent metals include alkali metals (such as sodium and potassium).
Examples of the divalent metal include alkaline earth metals (such as calcium and magnesium) and zinc.
As the amine, mono-, di- or tri-alkyl (1 to 8 carbon atoms) amine {monomethylamine, dimethylamine, trimethylamine, etc.}; mono-, di- or tri-alkanol (1 to 8 carbon atoms) amine { Monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine and diisopropanolamine etc.}; and heterocyclic amines {pyridine and morpholine etc.}.

As a monomer constituting the water-soluble anionic polymer, in addition to the anionic vinyl monomer (b1), a nonionic vinyl monomer (b2) and another monomer (b3) may be included.
Examples of the nonionic vinyl monomer (b2) include the following.

(B2-1) Carbamoyl group-containing vinyl monomer Unsubstituted or monoalkyl (1 to 4 carbon atoms) substituted (meth) acrylamide {(meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide N-i-propyl (meth) acrylamide and Nn- or i-butyl (meth) acrylamide}
Dialkyl (1 to 4 carbon atoms) substituted (meth) acrylamide {N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide and N, N-di-n-butyl (meth) acrylamide, etc.}
N-vinylcarboxylic acid amide {N-vinylformamide, N-vinylacetamide, N-vinyl-n- or i-propionylamide, N-vinylhydroxyacetamide, etc.}

(B2-2) Hydroxy group-containing vinyl monomer Hydroxy group-containing aromatic vinyl monomer {p-hydroxystyrene etc.}
Hydroxyalkyl (2-6 carbon atoms) (meth) acrylate {2-hydroxyethyl (meth) acrylate and 2- or 3-hydroxypropyl (meth) acrylate, etc.}
Mono- or di-hydroxyalkyl (1 to 4 carbon atoms) substituted (meth) acrylamide {N, N-dihydroxymethyl (meth) acrylamide, N, N-dihydroxypropyl (meth) acrylamide and N, N-di-2- Hydroxybutyl (meth) acrylamide etc.}
Vinyl acetate {vinyl alcohol units can be formed by hydrolysis. }
C3-C12 alkenol {(meth) allyl alcohol, crotyl alcohol, isocrotyl alcohol, 1-octenol, 1-undecenol, etc.}
C4-C12 alkenediol {1-buten-3-ol, 2-buten-1-ol, 2-butene-1,4-diol, etc.}
Hydroxyalkyl (C1-6) alkenyl (C3-10) ether {2-hydroxyethylpropenyl ether, etc.}
Alkenyl (carbon number 3 to 10) ethers of polyhydric (3 to 8 valent) alcohols (alkane polyols, intramolecular or intermolecular dehydrates, saccharides; glycerin, pentaerythritol, sorbitol, sorbitan, diglycerin, sucrose, etc.) or (Meth) acrylate {sucrose (meth) allyl ether, etc.}

(B2-3) Polyoxyalkylene chain-containing vinyl monomer (Meth) acrylate of polyoxyalkylene glycol (oxyalkylene group having 2 to 4 carbon atoms and polymerization degree of 2 to 50) {polyoxyethylene glycol (number average molecular weight 100) To 300) mono (meth) acrylate and polyoxypropylene glycol (number average molecular weight 130 to 500) mono (meth) acrylate, etc.}
Polyoxyalkylene glycol alkyl monoether (oxyalkylene group having 2 to 4 carbon atoms, polymerization degree 2 to 50) (meth) acrylate {methoxypolyoxyethylene glycol (number average molecular weight 110 to 310) (meth) acrylate and lauryl alcohol Ethylene oxide adduct (2 to 30 mol) (meth) acrylate, etc.}
Polyoxyalkylene polyol {polyoxyalkylene ether of polyhydric alcohol (alkyl group having 2 to 4 carbon atoms, degree of polymerization 2 to 100, etc.)} (meth) acrylate {mono (meth) acrylic acid polyoxyethylene (number average molecular weight) 150-230) sorbitan etc.}

  The number average molecular weight is a value obtained using GPC (measurement conditions are the same as those for measuring the weight average molecular weight, for example).

Examples of the other monomer (b3) include the following.
(B3-1) Epoxy group-containing vinyl monomer glycidyl (meth) acrylate, glycidyl (meth) allyl ether, etc.

(B3-2) Halogen atom-containing vinyl monomer Vinyl chloride, vinyl bromide, vinylidene chloride, (meth) allyl chloride, halogenated styrene (dichlorostyrene, etc.), etc.

(B3-3) Vinyl ester, vinyl ether, vinyl ketone Vinyl ester of saturated fatty acid (2 to 12 carbon atoms) {vinyl acetate, vinyl propionate, vinyl butyrate, vinyl octoate, etc.}
Vinyl ether of alkyl, aryl or alkoxyalkyl (C1-12) and vinyl {methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, 2-ethylhexyl vinyl ether, vinyl phenyl ether, vinyl 2-methoxyethyl ether and vinyl 2- Butoxyethyl ether, etc.}
Vinyl ketones of alkyl or aryl (1 to 8 carbon atoms) and vinyl {vinyl methyl ketone, vinyl ethyl ketone, vinyl phenyl ketone, etc.}

(B3-4) Unsaturated carboxylic acid ester Unsaturated monocarboxylic acid {(meth) acrylic acid, crotonic acid and the like} alkyl (alkyl having 1 to 30 carbon atoms) ester {alkyl having 1 to 30 carbon atoms ( (Meth) acrylate; methyl (meth) acrylate, ethyl (meth) acrylate, n- or i-propyl (meth) acrylate, n-, i- or t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, heptadecyl (Meth) acrylate, eicosyl (meth) acrylate, etc.}
Unsaturated monocarboxylic acid {(meth) acrylic acid, crotonic acid and the like} cycloalkyl (5 to 30 carbon atoms) ester {cycloalkyl (meth) acrylate having a cycloalkyl group having 5 to 30 carbon atoms; cyclopentyl (meth) acrylate 1-methyl-cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, cyclooctyl (meth) acrylate, adamantanyl (meth) acrylate, etc.}
Unsaturated monocarboxylic acid {(meth) acrylic acid, crotonic acid, etc.} aralkyl (7 to 30 carbon atoms) ester {aralkyl (meth) acrylate having 7 to 30 carbon atoms; benzyl (meth) acrylate and phenethyl (meth) acrylate, etc. }
Unsaturated dicarboxylic acid {maleic acid, fumaric acid, itaconic acid, etc.} alkyl (alkyl 1 to 8 carbon atoms) diester {dimethyl maleate, dimethyl fumarate, diethyl maleate, dioctyl maleate, etc.}

(B3-5) Vinyl group-containing hydrocarbon Alkene having 2 to 20 carbon atoms {ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, etc.}
C4-C12 alkadiene {butadiene, isoprene, 1,4-pentadiene, 1,6-heptadiene, 1,7-octadiene, etc.}
C6-C30 alicyclic hydrocarbon {cyclohexene, (di) cyclopentadiene, pinene, limonene, indene, vinylcyclohexene, ethylidenebicycloheptene, etc.}
Aromatic hydrocarbon {styrene, α-methyl styrene, 2,4-dimethyl styrene, 4-ethyl styrene, 4-isopropyl styrene, 4-butyl styrene, 4-phenyl styrene, 4-cyclohexyl styrene, 4-benzyl styrene, 4 -Crotylbenzene, 2-vinylnaphthalene, etc.}

(B3-6) cyano group or nitro group-containing vinyl monomer (meth) acrylonitrile, cyanostyrene, 4-nitrostyrene, etc.

  Specific examples of the water-soluble anion radical polymer having an SP value of 14 to 24 include (1) a heavy polymer consisting only of monomers having an SP value of 14 to 24 among the anionic vinyl monomers (b1). Combined {for example, disodium polymaleate (SP value = 16.2), disodium polyitaconate (SP value = 15.1), poly-3-acrylamido-2-hydroxypropanesulfonic acid (SP value = 16.3), etc. (2) A polymer which is a copolymer consisting only of an anionic vinyl monomer (b1) {for example, a poly (disodium maleate / sodium acrylate: molar ratio 50/50) copolymer (SP value) = 15.2) and poly (disodium maleate / sodium vinyl sulfonate: molar ratio 50/50) (SP value = 14.7) etc.}; (3) anionic vinyl monomer ( 1) a copolymer comprising a nonionic vinyl monomer (b2) {sodium acrylate / acrylamide (molar ratio 40/60) copolymer (SP value = 17.2) and sodium acrylate / hydroxyethyl methacrylate (Molar ratio 90/10) (SP value = 14.2), etc.]; (4) Polymer modified with a new anionic group after polymerization {for example, (meth) acrylamide or (meth) acrylonitrile is essential Examples include a polymer in which a polymer as a constituent monomer is hydrolyzed (hydrolysis with an aqueous hydrogen peroxide solution and / or an aqueous alkaline compound solution, etc.) to introduce a carboxy group}.

When the nonionic vinyl monomer (b2) unit is included, the content ratio {(b1) / (b2)} of the anionic vinyl monomer (b1) unit and the nonionic vinyl monomer (b2) unit (weight) The ratio is preferably 99/1 to 1/99, more preferably 95/5 to 5/95, and particularly preferably 90/10 to 10/90.
Further, when the other monomer (b3) unit is included, the content ratio {(b1) / (b3)} of the anionic vinyl monomer (b1) unit and the other monomer (b3) unit (weight) The ratio is preferably 99/1 to 60/40, more preferably 95/5 to 70/30, and particularly preferably 90/10 to 80/20.
Moreover, when it contains a nonionic vinyl monomer (b2) unit and another monomer (b3) unit, the content rate of a nonionic vinyl monomer (b2) unit and another monomer (b3) unit {(B2) / (b3)} (weight ratio) is preferably 99/1 to 60/40, more preferably 97/3 to 70/30, and particularly preferably 95/5 to 75/25.
In the above range, the bleaching efficiency is further improved.

  The weight average molecular weight of the water-soluble anion radical polymer is preferably from 1,500 to 10,000,000, more preferably from 2,000 to 5,000,000, particularly preferably from 3,000 to 1,000,000. When it is within this range, the bleaching efficiency is further improved.

  Water-soluble anionic non-radical polymers include anionic formaldehyde resins {4-hydroxybenzenesulfonic acid (salt) formalin condensate (condensation degree 2 to 200), naphthalenesulfonic acid (salt) formalin condensate (condensation degree 2 to 200). ) And 4-hydroxynaphthalenesulfonic acid (salt) formalin condensate (condensation degree 2 to 200), etc.} {Note that the salt includes a salt {monovalent metal salt, divalent metal salt, amine salt or ammonium salt}. It is. }; Polyester containing anionic group {Sulfo group-containing dicarboxylic acid (sulfosuccinic acid, sulfoisophthalic acid, 3,5-carbomethoxybenzene sulfonic acid, etc.) and / or sulfo group as a part of dicarboxylic acid component and / or diol component Water-soluble polyester obtained using a diol containing 2,5-bishydroxyethoxybenzenesulfonic acid, etc .; for example, a condensate of 1,5-dicarboxybenzenesulfonic acid and ethylene glycol}, an anionic group-containing polyurethane { As part of the active hydrogen atom-containing component, an anionic group-containing compound (a compound containing a sulfo group, a carboxy group, a sulfonate group or a carboxylate group, such as 1,3-dihydroxypropane 2-sulfonic acid, 1,3- Dihydroxy 2-methylpropane 2-carboxylic acid ) Water-soluble polyurethane introduced with an anionic group; for example, sulfo group-containing polyurethane (polymer comprising 1,3-dihydroxypropane 2-sulfonic acid and ethylene diisocyanate), carboxy group-containing polyurethane (1,3-dihydroxy) A polymer comprising 2-methylpropane 2-carboxylic acid and diethylene diisocyanate, etc.}.

  Examples of water-soluble anionic natural polymers include anionic polysaccharides {carboxy group-containing polymers; carboxymethyl cellulose (methyl group substitution degree 0.5 to 3.0), carboxyethyl cellulose (ethyl group substitution degree 0.5 to 2.4). ), Alginic acid (salt) and carboxymethyl chitin, etc .; sulfooxy group-containing polymer {chondroitin sulfate, sulfated chitosan, hyaluronic acid, cellulose sulfate, etc.}; phosphate starch; cellulose inorganic acid ester {cellulose nitrate, etc.}; anionic protein {Polyaspartic acid (salt); and polymer flocculant {written by Eizo Omori, published on January 10, 1975, pages 60 to 90}.

  Of the water-soluble anionic polymers, water-soluble anionic radical polymers and water-soluble anionic natural polymers are preferred, and water-soluble anionic radical weights having an anionic vinyl unit (b1) and a nonionic vinyl monomer (b2) are more preferred. Polymers, anionic polysaccharides and anionic proteins, particularly preferably water-soluble anionic radical polymers having only anionic vinyl units (b1), carboxymethylcellulose and polyaspartic acid (salt).

  Examples of the water-soluble nonionic polymer include a water-soluble nonionic radical polymer, a water-soluble nonionic non-radical polymer, a water-soluble nonionic natural polymer, and the like.

The water-soluble nonionic polymer includes a polymer having the nonionic vinyl monomer (b2) as an essential constituent monomer.
As a monomer constituting the water-soluble nonionic polymer, in addition to the nonionic vinyl monomer (b2), another monomer (b3) may be included.

  When the other monomer (b3) unit is included, the content ratio of the nonionic vinyl monomer (b2) unit and the other monomer (b3) unit {(b2) / (b3)} (weight ratio) Is preferably 99/1 to 65/35, more preferably 95/5 to 70/30, and particularly preferably 90/10 to 70/30. Within this range, the bleaching efficiency is further improved.

  The weight average molecular weight of the water-soluble nonionic polymer is preferably from 1,500 to 10,000,000, more preferably from 2,000 to 5,000,000, particularly preferably from 3,000 to 1,000,000. When it is within this range, the bleaching efficiency is further improved.

  Specific examples of the water-soluble nonionic radical polymer having an SP value of 14 to 24 include (1) a nonionic vinyl monomer (b2) consisting of only monomers having an SP value of 14 to 24. Combined {for example, polyacrylamide (SP value = 19.2), poly N-vinylformamide (SP value = 17.2) and polyvinyl alcohol (polyvinyl acetate saponification degree 60-100 mol%, weight average molecular weight 5, 000 to 200,000, SP value = 19.1 to 14.2) and the like}; (2) a polymer which is a copolymer of nonionic vinyl monomer (b2) and other monomers {for example, Saponified ethylene / vinyl acetate copolymer (SP value = 19.0 to 14.1), saponified butylene / vinyl acetate copolymer (SP value = 18.9 to 14.0), acrylylamide / vinyl acetate Copolymer saponified (SP value = 19.1 to 14.5) and the like} and the like.

  Examples of the water-soluble nonionic non-radical polymer include polyhydric alcohol dehydration condensates {polyglycerin and the like}; water-soluble nylon resins {condensates of succinic acid and N, N′dihydroxymethylethylenediamine, etc.}; water-soluble polyurethane resins { As a part of the polyol component, a water-soluble polyol obtained using a water-soluble polyol (ethylene glycol, polyoxyalkylene polyol mainly composed of oxyethylene groups (oxyethylene group content of 50% by weight or more, polymerization degree of 2 to 100), etc.) Polyurethane resin: polymer composed of ethylene diisocyanate and ethylene glycol} and the like.

  Examples of the water-soluble nonionic natural polymer include nonionic polysaccharides {water-soluble starch, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, ethyl cellulose, etc.}.

  Of the water-soluble nonionic polymers, a water-soluble nonionic radical polymer is preferable, a saponified product of polyvinyl alcohol and an ethylene / vinyl acetate copolymer is more preferable, and polyvinyl alcohol is particularly preferable.

  The water-soluble cationic polymer may be any water-soluble polymer having at least one cationic group {1-3 primary amino group, quaternary ammonio group, etc.] in one molecule. Cationic cationic non-radical polymers and water-soluble cationic natural polymers.

The water-soluble cationic radical polymer includes a polymer having the cationic vinyl monomer (b4) as an essential constituent monomer.
Examples of the cationic vinyl monomer (b4) include the following.
(B4-1) Primary to tertiary amino group-containing vinyl monomer Primary amino group-containing vinyl monomer {Alkylamine having 3 to 6 carbon atoms (such as (meth) allylamine and crotylamine), aminoalkyl (carbon number 2) -6) (Meth) acrylate (aminoethyl (meth) acrylate, etc.)}
Secondary amino group-containing vinyl monomer {alkyl (carbon number 1-6) aminoalkyl (carbon number 2-6) (meth) acrylate (t-butylaminoethyl methacrylate, methylaminoethyl (meth) acrylate), etc.], carbon Number 6 to 12 dialkenylamine (di (meth) allylamine, etc.)}
Tertiary amino group-containing vinyl monomer {dialkyl (1 to 4 carbon atoms) aminoalkyl (2 to 6 carbon atoms) (meth) acrylate (such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate), dialkyl (C1-C4) aminoalkyl (C2-C6) (meth) acrylamide (dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, etc.), tertiary amino group-containing aromatic vinyl monomer ( N, N-dimethylaminostyrene, etc.), nitrogen-containing heterocycle-containing vinyl monomers (morpholinoethyl (meth) acrylate, 4-vinylpyridine, 2-vinylpyridine, N-vinylpyrrole, N-vinylpyrrolidone and N-vinyl Thiopyrrolidone etc.); and their hydrochlorides, sulfates, phosphates, Grade carboxylate (1-8 carbon atoms), etc.

(B4-2) Quaternary ammonio group-containing vinyl monomer A primary to tertiary amino group-containing vinyl monomer (b4-1) is converted into a quaternizing agent (an alkyl chloride having 1 to 12 carbon atoms, 1 carbon atom). Quaternized with -6 dialkyl sulfuric acid, C1-C6 dialkyl carbonate, benzyl chloride, etc.) {(meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyltriethylammonium chloride, ( (Meth) acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloyloxyethylmethylmorpholino ammonium chloride, (meth) acryloylaminoethyltrimethylammonium chloride, (meth) acryloylaminoethyltriethylammonium chloride, (Meth) acryloylaminoethyldimethylbenzylammonium chloride, dimethyldiallylammonium methylsulfate, trimethylvinylphenylammonium chloride, etc.}.

  The monomer constituting the water-soluble cation radical polymer may include a nonionic vinyl monomer (b2) and / or other monomer (b3) in addition to the cationic vinyl monomer (b4). Good.

When the nonionic vinyl monomer (b2) unit is included, the content ratio of the cationic vinyl monomer (b4) unit and the nonionic vinyl monomer (b2) unit {(b4) / (b2)} (weight) The ratio is preferably 99/1 to 1/99, more preferably 95/5 to 5/95, and particularly preferably 90/10 to 10/90.
Further, when the other monomer (b3) unit is included, the content ratio {(b4) / (b3)} of the cationic vinyl monomer (b4) unit and the other monomer (b3) unit (weight) The ratio is preferably 99/1 to 60/40, more preferably 97/3 to 70/30, and particularly preferably 95/5 to 75/25.
Moreover, when it contains a nonionic vinyl monomer (b2) unit and another monomer (b3) unit, the content rate of a nonionic vinyl monomer (b2) unit and another monomer (b3) unit {(B2) / (b3)} (weight ratio) is preferably 99/1 to 60/40, more preferably 97/3 to 70/30, and particularly preferably 95/5 to 75/25.
In the above range, the bleaching efficiency is further improved.

  The weight average molecular weight of the water-soluble cationic polymer is preferably from 1,500 to 10,000,000, more preferably from 2,000 to 5,000,000, particularly preferably from 3,000 to 1,000,000. When it is within this range, the bleaching efficiency is further improved.

  Examples of the water-soluble cationic non-radical polymer include cationic formaldehyde resins {dicyandiamide-formalin condensates (condensation degree 3 to 500), etc.}; cationic group-containing water-soluble polyurethane resins {tertiary amino groups or quaternary ammonio groups. Water-soluble polyurethane (a polymer comprising 1,3-dihydroxypropane-2-trihydroxymethylammonium chloride and diethylene diisocyanate, using a quaternary nitrogen atom-containing polyol described in US Pat. No. 4,271,217) Cationization (neutralization or quaternization) of a water-soluble polyurethane resin having a quaternary ammonio group and a tertiary amino group-containing polyurethane as described in JP-B-42-19278 or JP-B-48-36958 And the like}.

  Water-soluble cationic natural polymers include cationic polysaccharides {cationized starch, chitosan, etc.}; and polymer flocculants {written by Eizo Omori, published on January 10, 1975, pages 35-59} Etc. are included.

  Of the water-soluble cationic polymers, water-soluble cationic radical polymers and water-soluble cationic natural polymers are preferable, water-soluble cationic radical polymers are more preferable, and cationized starch is particularly preferable.

  The water-soluble amphoteric polymer may be any water-soluble polymer having at least one cationic group and one anionic group per molecule, and includes a water-soluble amphoteric radical polymer and a water-soluble amphoteric natural polymer.

The water-soluble amphoteric radical polymer includes a polymer comprising an anionic vinyl monomer (b1) and a cationic vinyl monomer (b4) as essential constituent monomers.
The content ratio {(b4) / (b1)} (weight ratio) of the cationic vinyl monomer (b4) unit and the anionic vinyl monomer (b1) unit is preferably 5/95 to 95/5, More preferably, the ratio deviates from the vicinity of the isoelectric point (equivalence ratio 60/40 to 40/60), that is, 5/95 to 40/60 and 60/40 to 95/5, particularly preferably 10/90 to 30/70. And 70/30 to 90/10. Within this range, the bleaching efficiency is further improved.

  As monomers constituting the water-soluble amphoteric radical polymer, in addition to the anionic vinyl monomer (b1) and the cationic vinyl monomer (b4), a nonionic vinyl monomer (b2) and / or other The monomer (b3) may be included.

When the nonionic vinyl monomer (b2) unit is included, the content ratio of the anionic vinyl monomer (b1) and the cationic vinyl monomer (b4) unit to the nonionic vinyl monomer (b2) unit { (B1) + (b4) / (b2)} (weight ratio) is preferably 99/1 to 1/99, more preferably 95/5 to 5/95, and particularly preferably 90/10 to 10/90. is there.
Further, when the other monomer (b3) unit is included, the content ratio of the anionic vinyl monomer (b1) and the cationic vinyl monomer (b4) unit to the other monomer (b3) unit { (B1) + (b4) / (b3)} (weight ratio) is preferably 99/1 to 60/40, more preferably 97/3 to 70/30, and particularly preferably 95/5 to 75/25. is there.
Moreover, when it contains a nonionic vinyl monomer (b2) unit and another monomer (b3) unit, the content rate of a nonionic vinyl monomer (b2) unit and another monomer (b3) unit {(B2) / (b3)} (weight ratio) is preferably 99/1 to 60/40, more preferably 97/3 to 70/30, and particularly preferably 95/5 to 75/25.
In the above range, the bleaching efficiency is further improved.

  The weight average molecular weight of the water-soluble amphoteric radical polymer is preferably from 1,500 to 10,000,000, more preferably from 2,000 to 5,000,000, particularly preferably from 3,000 to 1,000,000. When it is within this range, the bleaching efficiency is further improved.

  Examples of the water-soluble amphoteric natural polymer include gelatin and water-soluble proteins represented by Nika.

  Of the water-soluble amphoteric polymers, the water-soluble amphoteric radical polymer consisting of (b1) and (b4) and the water-soluble amphoteric natural polymer are preferred, water-soluble amphoteric natural polymers are more preferred, and gelatin is particularly preferred.

  Of the water-soluble polymers (B), water-soluble anionic polymers and water-soluble nonionic polymers are preferred, water-soluble anionic radical polymers, water-soluble anionic natural polymers and water-soluble nonionic radical polymers, particularly preferably alginic acid ( Salt), polyaspartic acid (salt), carboxymethylcellulose, polymaleic acid (salt), polyitaconic acid (salt), acrylamide / acrylic acid (salt) copolymer, polyvinyl alcohol and polyacrylamide, most preferably polyvinyl alcohol and polyacrylamide It is.

  The weight average molecular weight of the water-soluble polymer (B) is preferably from 1,500 to 10,000,000, more preferably from 2,000 to 5,000,000, particularly preferably from 3,000 to 1,000,000. When it is within this range, the bleaching efficiency is further improved.

  Of the water-soluble polymer (B), the radical polymer can be produced by a conventional radical polymerization method (bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc.). Moreover, a non-radical polymer can be manufactured by the polymerization reaction (dehydration polymerization, addition polymerization, etc.) currently performed normally. As the natural polymer, an extract or purified product from a natural product can be used as it is. Further, it may be modified by a known chemical reaction (methylation reaction, hydroxyethylation, etc.).

  When the water-soluble polymer (B) is contained, the content (% by weight) of (B) is preferably 2 to 98, more preferably 5 to 95, particularly preferably based on the weight of the organic acid (A). 10-90. Within this range, the bleaching efficiency is further improved.

  As the surfactant (C), a known surfactant {for example, JP-A No. 2002-180391} can be used, and at least one of nonionic surfactant (C1), sulfo group, sulfooxy group, or phosphono group can be used. Anionic surfactant (C2), amphoteric surfactant (C3) and cationic surfactant (C4) having Of these, nonionic surfactant (C1), anionic surfactant (C2) having at least one of sulfo group, sulfooxy group or phosphono group and amphoteric surfactant (C3) are preferable, and nonionic surfactant is more preferable. Agent (C1) and an anionic surfactant (C2) having at least one of a sulfo group, a sulfooxy group or a phosphono group, particularly preferably a nonionic surfactant (C1), most preferably a polyoxyalkylene alkyl (having 4 to 4 carbon atoms) 24) Ether, polyoxyalkylene alkyl (4 to 24 carbon atoms) phenyl ether, polyoxyalkylene alkyl (4 to 24 carbon atoms) amide and polyether-modified silicone.

6-18 are preferable, as for HLB of surfactant (C), More preferably, it is 7-17, Most preferably, it is 8-16. Within this range, a higher penetration effect is obtained and the bleaching efficiency is further improved.
Here, HLB shows the balance between organic and inorganic, and is an abbreviation for Hydrophile-Liophile Balance. HLB is a numerical value based on the Oda method, and can be calculated by summing up numerical values indicating organicity and inorganicity (Oda, Teramura, “Synthesis and Application of Surfactants” on page 501).

  When the surfactant (C) is contained, the content (% by weight) of the surfactant (C) is preferably 2 to 98, more preferably 5 to 95, based on the weight of the organic acid (A). Especially preferably, it is 10-90.

The bleaching aid of the present invention may further contain an antifoaming agent (D), a solvent (E) and / or other additives (F) as necessary.
As the antifoaming agent (D), known antifoaming agents {polyether antifoaming agent, animal and plant mineral oil defoaming agent, silicone antifoaming agent, wax emulsion defoaming agent, etc.} can be used.

  When the antifoaming agent (D) is contained, the content (% by weight) of the antifoaming agent (D) is preferably 2 to 50, more preferably 5 to 40, based on the weight of the organic acid (A). Especially preferably, it is 10-30.

Examples of the solvent (E) include water or a mixed solvent of water and a hydrophilic organic solvent.
Examples of hydrophilic organic solvents include esters having 4 to 8 carbon atoms {ethyl acetate, butyl acetate, methoxybutyl acetate, methyl cellosolve acetate and ethyl cellosolve acetate}, ethers having 4 to 8 carbon atoms {ethyl cellosolve, butyl cellosolve and propylene glycol. Monomethyl ether and the like}, ketones having 3 to 8 carbon atoms {acetone, methyl ethyl ketone and methyl isobutyl ketone, etc.}, alcohols having 1 to 8 carbon atoms {methanol, ethanol, n- or i-propanol, n-, i- or t- Butanol, propylene glycol, dipropylene glycol and the like}, and C5-C8 heterocyclic compounds {N-methylpyrrolidone and the like}. Among these, water, a mixed solvent of water and ether, and a mixed solvent of water and alcohol are preferable, and water is particularly preferable.
When a mixed solvent of water and a hydrophilic organic solvent is used as the solvent, the content ratio by weight of water / hydrophilic organic solvent (water / hydrophilic organic solvent) is preferably 1 to 200, more preferably 1.5 to 100, particularly preferably 2-50.

  When the solvent (E) is contained, the content (% by weight) of the solvent (E) is preferably 1 to 99, more preferably 5 to 95, particularly preferably 10 based on the weight of the organic acid (A). ~ 90.

  Other additives (F) include known additives {dispersants, water resistance agents, water retention agents, thickeners, surface sizing agents, fluidity improvers, lubricants, wetting agents, antioxidants, UV absorption. Agent, deodorant, fragrance, dye, filler, slime control agent, pitch control agent and / or preservative, etc.}.

  When the other additive (F) is contained, the content (% by weight) of the other additive (F) is preferably 2 to 50, more preferably 5 to 5 based on the weight of the organic acid (A). 40, particularly preferably 10-30.

  In addition to the organic acid (A) and / or salt thereof, the bleaching aid of the present invention is a water-soluble polymer (B), a surfactant (C), an antifoaming agent (D), a solvent (E), and / or other. When the additive (F) is included, the bleaching aid of the present invention comprises an organic acid (A), a water-soluble polymer (B), a surfactant (C), an antifoaming agent (D), a solvent (E ) And / or other additives (F).

The bleaching aid of the present invention comprises an organic acid (A) and / or a salt thereof, a water-soluble polymer (B), a surfactant (C), an antifoaming agent (D), a solvent (E) and / or the like. The additive (F) may be added separately in the same step, or may be added separately in a separate step.
The step of adding the bleaching aid of the present invention is any of the oxygen bleaching step, the washing step after the oxygen bleaching step, the chlorine dioxide bleaching step, the washing step after the chlorine dioxide bleaching step, and the alkali extraction step after chlorine dioxide bleaching. Good. Of these, the oxygen bleaching step, the washing step after the oxygen bleaching step, and the oxygen bleaching step are more preferable.
Moreover, the addition method may add to a pulp slurry, and may add to the filtrate of a washing | cleaning process (it is preferable to add to a pulp slurry). Further, it may be added to a plurality of steps or may be added to one step. Further, the bleaching aid of the present invention may be added after diluting in water, or may be added continuously or intermittently.

The addition amount (% by weight) of the bleaching aid of the present invention is preferably 1 × 10 ⁻⁵ to 4, more preferably 1 × 10 ⁻⁴ to, based on the absolute dry weight (%) of the cellulose pulp. 2, particularly preferably in an amount of 1 × 10 ^{−3 to} 0.5. Within this range, the bleaching efficiency is further improved.
The absolute dry weight means the weight after drying to a constant weight at 105 ° C. (hereinafter the same).

  Cellulose pulp to which the bleaching aid of the present invention can be applied includes chemical pulp {CGP (chemipulp pulp), SCP (semi-chemical pulp), SP (sulfide pulp), KP (craft pulp), etc.}; mechanical pulp {GP ( Groundwood pulp), RMP (refiner mechanical pulp), TMP (thermomechanical pulp) and the like}; used paper pulp and the like.

  By using the bleaching aid of the present invention, the bleaching efficiency in the bleaching step is improved, and a high whiteness pulp can be produced. In addition, in the bleaching process at the time of producing high whiteness pulp, in addition to oxygen bleaching, chlorine dioxide bleaching, chlorine bleaching, hypochlorous acid bleaching, hydrogen peroxide bleaching, ozone bleaching or bleaching combining these is performed. However, since the bleaching efficiency is improved, the amount of bleaching chemicals such as chlorine dioxide, chlorine, hypochlorous acid, hydrogen peroxide, sodium hydroxide and ozone can be reduced.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples. Parts and% mean parts by weight and% by weight unless otherwise specified.

<Production Example 1>
After dehydrating 186 parts (1 mole) of lauryl alcohol and 0.2 part of potassium hydroxide for 1 hour at 120 ° C. under reduced pressure in a nitrogen atmosphere, 132 parts (3 moles) of ethylene oxide and a gauge pressure of 1 at 150 ° C. It dripped over 5 hours so that it might become -3kgf / cm < ² >. Subsequently, the mixture was aged at the same temperature for 1 hour to obtain a nonionic surfactant {ethylene oxide adduct of lauryl alcohol (average number of moles added: 3, HLB value: about 6) (C11).

<Production Example 2>
After dehydrating 186 parts (1 mole) of lauryl alcohol and 0.2 part of potassium hydroxide for 1 hour at 120 ° C. under reduced pressure in a nitrogen atmosphere, 440 parts (10 moles) of ethylene oxide at 150 ° C. with a gauge pressure of 1 It dripped over 5 hours so that it might become -3kgf / cm < ² >. Subsequently, the mixture was aged at the same temperature for 1 hour to obtain a nonionic surfactant {ethylene oxide adduct of lauryl alcohol (average added mole number: 10, HLB value: about 13) (C12).

<Example 1>
90 parts of the solvent {water} (E1) and 10 parts of an organic acid salt {made by Nacalai Tesque, Inc., lithium lactate} (A21) were uniformly mixed at 25 ° C. to obtain the bleaching assistant 1 of the present invention.

<Example 2>
90 parts of the solvent (E1) and 10 parts of organic acid {manufactured by Nacalai Tesque, DL-malic acid} (A22) were uniformly mixed at 25 ° C. to obtain the bleaching aid 2 of the present invention.

<Example 3>
90 parts of a solvent (E1) and 10 parts of an organic acid salt {manufactured by Nacalai Tesque Co., Ltd., tripotassium citrate monohydrate} (A23) are uniformly mixed at 25 ° C. to obtain the bleaching aid 3 of the present invention. Obtained.

<Example 4>
90 parts of the solvent (E1) and 10 parts of an organic acid salt {manufactured by Nacalai Tesque, Inc., dipotassium ethylenediaminetetraacetate} (A11) were uniformly mixed at 25 ° C. to obtain the bleaching assistant 4 of the present invention.

<Example 5>
Solvent (E1) 78 parts and organic acid salt {BASF Japan Co., Ltd., sodium polyacrylate, Sokalan PA-15, 45% aqueous solution, weight average molecular weight 1200} (A31) 22 parts are uniformly mixed at 25 ° C. Thus, the bleaching assistant 5 of the present invention was obtained.

<Example 6>
80 parts of solvent (E1) and organic acid {BASF Japan KK, acrylic acid / maleic acid copolymer, Sokalan CP 12S, 50% aqueous solution, weight average molecular weight 3000} (A32) 20 parts are uniformly mixed at 25 ° C. Thus, the bleaching assistant 6 of the present invention was obtained.

<Example 7>
90 parts of solvent (E1), 4 parts of organic acid (A22) and water-soluble polymer {formalin condensate of sodium naphthalene sulfonate manufactured by San Nopco Co., Ltd., SN-PW 43, SP value: 14.4} (B1) 6 parts Were uniformly mixed at 25 ° C. to obtain Bleaching Aid 7 of the present invention.

<Example 8>
90 parts of the solvent (E1), 4 parts of the organic acid (A22) and 6 parts of the water-soluble polymer {Kuraray Co., Ltd. polyvinyl alcohol, PVA217, SP value: 17.2} (B2) were uniformly mixed at 25 ° C. The bleaching assistant 8 of the present invention was obtained.

<Example 9>
90 parts of the solvent (E1), 4 parts of the organic acid (A22), and 6 parts of the water-soluble polymer {Nacalai Tesque Co., Ltd. starch, soluble starch, SP value: 23.5} (B3) were uniformly mixed at 25 ° C. The bleaching assistant 9 of the present invention was obtained.

<Example 10>
90 parts of the solvent (E1), 4 parts of the organic acid (A22) and 6 parts of the nonionic surfactant {ethylene oxide adduct of lauryl alcohol} (C11) obtained in Production Example 1 were uniformly mixed at 25 ° C. Bleaching aid 10 was obtained.

<Example 11>
90 parts of the solvent (E1), 4 parts of the organic acid (A22), and 6 parts of the nonionic surfactant {ethylene oxide adduct of lauryl alcohol} (C12) obtained in Production Example 2 were uniformly mixed at 25 ° C. The bleaching assistant 11 was obtained.

<Example 12>
Solvent (E1) 90 parts, organic acid (A22) 4 parts and anionic surfactant {Sigma Aldrich Co., Ltd., sodium tetradecyl sulfate, HLB: about 18} (C21) 6 parts are uniformly mixed at 25 ° C. A bleaching assistant 12 of the present invention was obtained.

<Example 13>
90 parts of the solvent (E1), 3 parts of the organic acid (A22), 3 parts of the water-soluble polymer (B1) and 4 parts of the nonionic surfactant (C11) obtained in Production Example 1 were uniformly mixed at 25 ° C. A bleaching assistant 13 according to the present invention was obtained.

<Example 14>
90 parts of the solvent (E1), 3 parts of the organic acid (A22), 3 parts of the water-soluble polymer (B1) and 4 parts of the nonionic surfactant (C12) obtained in Production Example 2 were uniformly mixed at 25 ° C. The bleaching assistant 14 of the present invention was obtained.

<Example 15>
The bleaching aid of the present invention is obtained by uniformly mixing 90 parts of a solvent (E1), 3 parts of an organic acid (A22), 3 parts of a water-soluble polymer (B1) and 4 parts of an anionic surfactant (C21) at 25 ° C. 15 was obtained.

<Example 16>
90 parts of the solvent (E1), 3 parts of the organic acid (A22), 3 parts of the water-soluble polymer (B2) and 4 parts of the nonionic surfactant (C11) obtained in Production Example 1 were uniformly mixed at 25 ° C. A bleaching assistant 16 of the present invention was obtained.

<Example 17>
90 parts of the solvent (E1), 3 parts of the organic acid (A22), 3 parts of the water-soluble polymer (B2) and 4 parts of the surfactant (C12) obtained in Production Example 2 were uniformly mixed at 25 ° C. Of Bleaching Aid 17 was obtained.

<Example 18>
90 parts of the solvent (E1), 3 parts of the organic acid (A22), 3 parts of the water-soluble polymer {(B2) and 4 parts of the anionic surfactant (C21) were uniformly mixed at 25 ° C. Agent 18 was obtained.

<Example 19>
90 parts of the solvent (E1), 3 parts of the organic acid (A22), 3 parts of the water-soluble polymer (B3) and 4 parts of the nonionic surfactant (C11) obtained in Production Example 1 were uniformly mixed at 25 ° C. A bleaching assistant 19 of the present invention was obtained.

<Example 20>
90 parts of the solvent (E1), 3 parts of the organic acid (A22), 3 parts of the water-soluble polymer (B3) and 4 parts of the nonionic surfactant (C12) obtained in Production Example 2 were uniformly mixed at 25 ° C. A bleaching assistant 20 of the present invention was obtained.

<Example 21>
90 parts of solvent (E1), 3 parts of organic acid (A22), 3 parts of water-soluble polymer (B3) and 4 parts of anionic surfactant (C21) are uniformly mixed at 25 ° C. 21 was obtained.

<Example 22>
90 parts of solvent (E1), 3 parts of organic acid (A22), 3 parts of water-soluble polymer (B3), 4 parts of surfactant (C21) and defoamer {Polyether defoamer manufactured by San Nopco, SN deformer 265} (D1) 0.01 part was uniformly mixed at 25 ° C. to obtain the bleaching assistant 22 of the present invention.

<Example 23>
900 g of hardwood mixed wood chips consisting of 50% Japanese hardwood and 50% eucalyptus wood were collected, and this was used as a liquid ratio of 5 and effective alkali per chip dry weight {effective alkali is JIS P0001: This means “a method of displaying the amount of alkali that causes the cooking action of the kraft cooking liquid, effective alkali = NaOH + Na ₂ S × 1/2, converted into Na ₂ O or NaOH” as defined in 1998. } After kraft cooking using an autoclave for indirect heating for experiments under the conditions of 18%, sulfidity of cooking liquid 25%, cooking temperature 160 ° C, cooking time 120 minutes, waste liquid and pulp are separated, and pulp is slit Selection was performed using a flat screen equipped with a screen plate having a width of 0.25 mm to obtain hardwood unbleached kraft pulp {ISO whiteness 34.0%, copper number 20.8, pulp viscosity 28.3 mPa · s}.

Next, this hardwood unbleached kraft pulp was collected in an indirectly heated autoclave, and 2.0% of caustic soda was added to the dry weight of the pulp, and the bleaching assistant 1 obtained in Example 1 was added to 2 per dry weight of the pulp. After adding 0.0% and then diluting with ion-exchanged water to adjust the pulp concentration to 10%, pressurize with compressed oxygen gas having a purity of 99.9% by volume so that the gauge pressure becomes 5 kg / cm ² , Heat at 100 ° C. for 60 minutes, perform alkali oxygen delignification by the medium concentration method, wash the obtained pulp with ion-exchanged water, dehydrate and wash, and then bleach oxygen pulp (1) {ISO whiteness 49.0%, a copper number of 10.2, and a pulp viscosity of 22.8 mPa · s} were obtained.

  The oxygen bleached pulp (1) was then placed in a plastic bag and diluted with a pH 3.5 aqueous sulfuric acid solution (prepared from ion-exchanged water and concentrated sulfuric acid.) To adjust the pulp concentration to 10%. Bleaching of the first stage of chlorine dioxide (hereinafter abbreviated as D0 stage) was performed by adding 0.75% of chlorine dioxide per weight and immersing in a constant temperature water bath at a temperature of 70 ° C. for 60 minutes. After washing with exchanged water, dehydration and washing were performed to obtain pulp after D0 stage.

  After the D0 stage, the pulp is put in a plastic bag, and the pulp concentration is adjusted to 10% using ion-exchanged water. Then, 1.2% of caustic soda is added to the dry weight of the pulp and treated at a temperature of 70 ° C. for 150 minutes. An extraction stage (hereinafter abbreviated as E stage) was performed. The obtained pulp was washed with ion-exchanged water, then dehydrated and washed to obtain post-E stage pulp.

  Subsequently, the pulp after stage E is put in a plastic bag, diluted with a pH 3.5 sulfuric acid aqueous solution (prepared from ion-exchanged water and concentrated sulfuric acid) to adjust the pulp concentration to 10%, and then the absolute dry weight of the pulp. Chlorine dioxide was added at a rate of 0.25% per unit, treated for 300 minutes at a temperature of 70 ° C., and subjected to second-stage chlorine dioxide bleaching, washed with ion-exchanged water, dehydrated, and bleached pulp ( 1) {ISO whiteness 84.0%, pulp viscosity 20.8 mP · s} was obtained.

<Example 24>
Oxygen bleached pulp (2) and bleached pulp (2) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 2”.

<Example 25>
Oxygen bleached pulp (3) and bleached pulp (3) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 3”.

<Example 26>
Oxygen bleached pulp (4) and bleached pulp (4) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 4”.

<Example 27>
Oxygen bleached pulp (5) and bleached pulp (5) were obtained in the same manner as in Example 23, except that “Bleaching Aid 1” was changed to “Bleaching Aid 5”.

<Example 28>
Except that “Bleaching Aid 1” was changed to “Bleaching Aid 6”, in the same manner as in Example 23,
Oxygen bleached pulp (6) and bleached pulp (6) were obtained.

<Example 29>
Same as Example 23, except that “Bleaching Aid 1 2.0% added per dry dry weight of pulp” was changed to “Bleaching Aid 2 added 1 × 10 ⁻³ % per dry dry weight of pulp” Thus, oxygen bleached pulp (7) and bleached pulp (7) were obtained.

<Example 30>
Oxygen bleaching was carried out in the same manner as in Example 23 except that “Bleaching aid 1 was added at 2.0% per pulp dry weight” was changed to “Bleaching aid 2 at 40% per pulp dry weight”. Pulp (8) and bleached pulp (8) were obtained.

<Example 31>
Oxygen bleached pulp (9) and bleached pulp (9) were obtained in the same manner as in Example 23, except that “Bleaching Aid 1” was changed to “Bleaching Aid 7”.

<Example 32>
Oxygen bleached pulp (10) and bleached pulp (10) were obtained in the same manner as in Example 23, except that “Bleaching Aid 1” was changed to “Bleaching Aid 8”.

<Example 33>
Oxygen bleached pulp (11) and bleached pulp (11) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 9”.

<Example 34>
Oxygen bleached pulp (12) and bleached pulp (12) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 10”.

<Example 35>
Oxygen bleached pulp (13) and bleached pulp (13) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 11”.

<Example 36>
Oxygen bleached pulp (14) and bleached pulp (14) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 12”.

<Example 37>
Oxygen bleached pulp (15) and bleached pulp (15) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 13”.

<Example 38>
Oxygen bleached pulp (16) and bleached pulp (16) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 14”.

<Example 39>
Oxygen bleached pulp (17) and bleached pulp (17) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 15”.

<Example 40>
Oxygen bleached pulp (18) and bleached pulp (18) were obtained in the same manner as in Example 23, except that “Bleaching Aid 1” was changed to “Bleaching Aid 16”.

<Example 41>
Oxygen bleached pulp (19) and bleached pulp (19) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 17”.

<Example 42>
Oxygen bleached pulp (20) and bleached pulp (20) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 18”.

<Example 43>
Oxygen bleached pulp (21) and bleached pulp (21) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 19”.

<Example 44>
Oxygen bleached pulp (22) and bleached pulp (22) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 20”.

<Example 45>
Oxygen bleached pulp (23) and bleached pulp (23) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 21”.

<Example 46>
Oxygen bleached pulp (24) and bleached pulp (24) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was changed to “Bleaching Aid 22”.

<Comparative Example 1>
Oxygen bleached pulp (H1) and bleached pulp (H1) were obtained in the same manner as in Example 23 except that “Bleaching Aid 1” was not used.

<Comparative example 2>
Except for changing “Bleaching Aid 1 to 2.0% per dry dry weight of pulp” to “Add 0.2% of water soluble polymer (B2) per dry dry weight of pulp” and Example 23 Similarly, oxygen bleached pulp (H2) and bleached pulp (H2) were obtained.

<Comparative Example 3>
Example 23, except that “2.0% addition of bleaching assistant 1 per absolute dry weight of pulp” was changed to “0.2% addition of nonionic surfactant (C12) per absolute dry weight of pulp” In the same manner as above, oxygen bleached pulp (H3) and bleached pulp (H3) were obtained.

<Comparative Example 4>
"Bleaching aid 1 added at 2.0% per pulp dry weight""Water-soluble polymer (B2) and nonionic surfactant (C12) added at 0.1% per pulp dry weight respectively Except that it was changed to "", oxygen bleached pulp (H4) and bleached pulp (H4) were obtained in the same manner as in Example 23.

About the oxygen bleached pulp and bleached pulp obtained in Examples 23 to 46 and Comparative Examples 1 to 4, pulp whiteness was measured and shown in Tables 1 and 2.
Incidentally, the pulp brightness is to prepare a sheet having a basis weight of 60 g / ^{m 2} in compliance with JIS P8209 (1994 years), this sheet was measured according to JIS P8124 (2000 years). It shows that bleaching efficiency is so high that the numerical value of pulp whiteness is high.

When the bleaching assistant of the present invention (Examples 1 to 22) was used, a pulp having a remarkably high whiteness could be easily obtained.
Accordingly, less bleaching agent is required to obtain pulp having the same whiteness, and the amount of bleaching agent used can be reduced. In addition, the bleaching aid of the present invention has little adverse effect on the environment, and can realize environmentally friendly bleaching in combination with the effect of reducing the amount of bleach used.

Claims (6)

A bleaching aid used in the bleaching process of cellulose pulp with chlorine dioxide,
Oh Kishikarubon acid, bleaching aids, characterized by containing an organic acid (A) and / or a salt selected either et tricarboxylic acid or tetracarboxylic acid. Bleaching aid according to claim 1 the organic acid (A) is O Kishikarubon acid. The bleaching aid according to claim 1 or 2, further comprising a water-soluble polymer (B) having a solubility parameter of 14 to 24 and / or a surfactant (C) having an HLB of 6 to 18. The surfactant (C) comprises a nonionic surfactant (C1); an anionic surfactant (C2) having at least one of a sulfo group, a sulfooxy group or a phosphono group; and an amphoteric surfactant (C3). The bleaching assistant according to claim 3, which is at least one selected from the group. The manufacturing method of the bleached cellulose pulp characterized by including the bleaching process of adding the bleaching assistant in any one of Claims 1-4 to a cellulose pulp slurry, and bleaching a cellulose pulp. The method for producing a bleached cellulose pulp according to claim 5, wherein the addition amount of the bleaching assistant is 1 x ^10-4 to 4% by weight per the dry weight of the cellulose pulp.