JP6897227B2 - Paper strength enhancer, paper manufacturing method, and paper - Google Patents

Paper strength enhancer, paper manufacturing method, and paper Download PDF

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JP6897227B2
JP6897227B2 JP2017064281A JP2017064281A JP6897227B2 JP 6897227 B2 JP6897227 B2 JP 6897227B2 JP 2017064281 A JP2017064281 A JP 2017064281A JP 2017064281 A JP2017064281 A JP 2017064281A JP 6897227 B2 JP6897227 B2 JP 6897227B2
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JP2017186725A (en
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浩之 井岡
浩之 井岡
尚吾 西浦
尚吾 西浦
国博 廣瀬
国博 廣瀬
大輔 藤岡
大輔 藤岡
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Arakawa Chemical Industries Ltd
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    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/20Macromolecular organic compounds
    • D21H17/33Synthetic macromolecular compounds
    • D21H17/34Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D21H17/41Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups
    • D21H17/44Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups cationic
    • D21H17/45Nitrogen-containing groups
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10Esters
    • C08F220/34Esters containing nitrogen, e.g. N,N-dimethylaminoethyl (meth)acrylate
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/52Amides or imides
    • C08F220/54Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
    • C08F220/56Acrylamide; Methacrylamide
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/63Inorganic compounds
    • D21H17/67Water-insoluble compounds, e.g. fillers, pigments
    • D21H17/675Oxides, hydroxides or carbonates
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/63Inorganic compounds
    • D21H17/67Water-insoluble compounds, e.g. fillers, pigments
    • D21H17/68Water-insoluble compounds, e.g. fillers, pigments siliceous, e.g. clays
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/14Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
    • D21H21/18Reinforcing agents

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Paper (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Description

本発明は、力増強剤、の製造方法、及びに関する。
The present invention, paper strengthening agent, a method of manufacturing a paper, and a paper.

印刷用紙及び筆記用紙等の紙には、通常、タルクやカオリン、炭酸カルシウム等の無機填料が使用されている。特に炭酸カルシウムは、紙の不透明化、白色化及び平滑化に優れ、印刷適性を高めることから、製紙業界における使用量は年々増加傾向にある。以下、無機填料を多く含む紙を「高灰分紙」という。 Inorganic fillers such as talc, kaolin, and calcium carbonate are usually used for printing paper, writing paper, and the like. In particular, calcium carbonate is excellent in opacity, whitening and smoothing of paper and enhances printability, so that the amount used in the paper industry is increasing year by year. Hereinafter, paper containing a large amount of inorganic filler is referred to as "high ash separation paper".

しかし、高灰分紙は、無機填料の含有量が増えるほど、引張強さや内部強度等が低下する傾向にある。パルプ繊維間に無機填料が多く存在する結果、繊維同士の絡み合いや、水素結合を介した相互作用が阻害されるためであると考えられている。 However, the tensile strength, internal strength, and the like of high ash paper tend to decrease as the content of the inorganic filler increases. It is considered that this is because a large amount of inorganic filler is present between pulp fibers, and as a result, entanglement between fibers and interaction via hydrogen bonds are hindered.

そこで従来、高灰分紙の強度を補う目的で、ポリアクリルアミドやカチオン化デンプン等の紙力増強剤が使用されてきており、種々改良が重ねられている。特に両性ポリアクリルアミドは、そのカチオン性基においてパルプに直接定着し、また、そのアニオン性基が(硫酸バンド等の補助材を介して)パルプに間接定着するため、高い紙力増強効果を奏する。 Therefore, conventionally, paper strength enhancers such as polyacrylamide and cationized starch have been used for the purpose of supplementing the strength of high ash paper, and various improvements have been made. In particular, amphoteric polyacrylamide has a high effect of enhancing paper strength because its cationic group is directly fixed to pulp and its anionic group is indirectly fixed to pulp (via an auxiliary material such as a sulfate band).

一方、斯界では古紙を原料とするリサイクル紙の需要が依然伸長している。しかし、古紙パルプは短繊維化と劣化が進んだものであるため、両性ポリアクリルアミドが定着し難いとされる。この点、カチオン性基の量を増やすことが考えられるが、そのような両性ポリアクリルアミドは凝集力が強いため、成紙の地合いを乱したり、紙力効果が寧ろ劣ったりする。 On the other hand, the demand for recycled paper made from used paper is still growing in this world. However, since recycled paper pulp has been shortened and deteriorated, it is difficult for amphoteric polyacrylamide to settle. In this respect, it is conceivable to increase the amount of cationic groups, but since such amphoteric polyacrylamide has a strong cohesive force, the texture of the paper is disturbed or the paper strength effect is rather inferior.

そこで本出願人は、特許文献1において、所定のパラメータを備える両性ポリアクリルアミドを用いた紙力増強剤が、成紙の地合いを乱さず、かつ、紙力も優れることを示した。しかし、当該紙力増強剤は、前記高灰分紙、特に無機填料として炭酸カルシウムを多く含む紙に適用すると、所期の効果が損なわれる場合があることが判明した。 Therefore, the applicant has shown in Patent Document 1 that a paper strength enhancer using an amphoteric polyacrylamide having a predetermined parameter does not disturb the texture of the finished paper and has excellent paper strength. However, it has been found that when the paper strength enhancer is applied to the high ash paper, particularly paper containing a large amount of calcium carbonate as an inorganic filler, the desired effect may be impaired.

特開2014−196588号公報 Japanese Unexamined Patent Publication No. 2014-196588

本発明は、無機填料を多く含むパルプスラリーに添加した場合であっても、パルプ繊維に定着しやすく、紙力増強効果に優れ、かつ成紙の地合を乱さない、新規な両性ポリアクリルアミドを含む紙力増強剤を提供することを主たる課題とする。 The present invention provides a novel amphoteric polyacrylamide that easily adheres to pulp fibers, has an excellent effect of enhancing paper strength, and does not disturb the texture of the grown paper even when added to a pulp slurry containing a large amount of inorganic filler. The main task is to provide a paper strength enhancer containing the mixture.

本発明者は、特許文献1の所定パラメータで規定された両性ポリアクリルアミドにおける上記問題を解消するべく検討した。結果、該両性ポリアクリルアミドが無機填料、特に炭酸カルシウムを多く含むパルプスラリーに適用した場合に効果が減少する一因として、両性ポリアクリルアミドのパルプ繊維への定着が著しく妨げられるためであると考えられた。 The present inventor has studied to solve the above-mentioned problem in the amphoteric polyacrylamide defined by the predetermined parameters of Patent Document 1. As a result, it is considered that one of the reasons why the effect of the amphoteric polyacrylamide is reduced when it is applied to an inorganic filler, particularly a pulp slurry containing a large amount of calcium carbonate, is that the fixation of the amphoteric polyacrylamide to the pulp fiber is significantly hindered. It was.

そこで本発明者は、前記パラメータを最適化し、かつ、該文献1には明示的に記載されていない物性条件を特定することによって、前記課題を解決し得る紙力増強剤が得られることを見出した。 Therefore, the present inventor has found that a paper strength enhancer capable of solving the above problems can be obtained by optimizing the parameters and specifying physical property conditions not explicitly described in the document 1. It was.

すなわち、本発明は、以下に示す高灰分紙用紙力増強剤、高灰分紙の製造方法、及び高灰分紙に関する。 That is, the present invention relates to the following high ash paper strength enhancer, a method for producing a high ash paper, and a high ash paper.

1.下記要件〔1〕、〔2〕、〔3〕、〔4〕及び〔5〕を備える両性ポリアクリルアミドを含有する、高灰分紙用紙力増強剤。
〔1〕その構成成分(1)がアクリルアミド(a)、αメチル基含有カチオン性ビニルモノマー(b)、アニオン性ビニルモノマー(c)を含む
〔2〕その構成成分(1)における(b)成分の比率が1〜15モル%であり、かつ、(c)成分の比率が1〜10モル%である
〔3〕そのH−NMRスペクトルの0.9ppm〜1.35ppmの範囲に該(b)成分のαメチル基に帰属する高磁場側吸収帯Aと低磁場側吸収帯Bがあり、かつ、該吸収帯Aの面積(As)及び該吸収帯Bの面積(Bs)の合計面積に対する該吸収帯Aの面積(As)の比率[As/(As+Bs)]が10〜35%である
〔4〕その15重量%水溶液(25℃)の粘度が2,000〜60,000mPa・sである
〔5〕その重量平均分子量(Mw)と数平均分子量(Mn)の比率(Mw/Mn)が3.5以下である
1. 1. A high ash paper strength enhancer containing an amphoteric polyacrylamide having the following requirements [1], [2], [3], [4] and [5].
[1] The component (1) contains acrylamide (a), an α-methyl group-containing cationic vinyl monomer (b), and an anionic vinyl monomer (c) [2] The component (b) in the component (1). The ratio of (c) is 1 to 10 mol%, and the ratio of the component (c) is 1 to 10 mol%. [3] Part 1 The (b) is in the range of 0.9 ppm to 1.35 ppm of the H-NMR spectrum. ) There are a high magnetic field side absorption band A and a low magnetic field side absorption band B belonging to the α-methyl group of the component, and the total area of the absorption band A (As) and the absorption band B (Bs). The ratio [As / (As + Bs)] of the area (As) of the absorption band A is 10 to 35% [4] The viscosity of the 15% by weight aqueous solution (25 ° C.) is 2,000 to 60,000 mPa · s. [5] The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3.5 or less.

2.構成成分(1)における(a)成分の比率が55〜97.8モル%である、前記項1の紙力増強剤。 2. Item 3. The paper strength enhancer according to Item 1, wherein the ratio of the component (a) to the component (1) is 55 to 97.8 mol%.

3.(b)成分が、第3級アミノ基含有メタクリレート、第3級アミノ基含有メタクリルアミド、第4級塩構造含有メタクリレート、及び第4級塩構造含有メタクリルアミドからなる群より選ばれる少なくとも一種である、前記項1又は2の紙力増強剤。 3. 3. The component (b) is at least one selected from the group consisting of a tertiary amino group-containing methacrylate, a tertiary amino group-containing methacrylamide, a quaternary salt structure-containing methacrylate, and a quaternary salt structure-containing methacrylamide. , The paper strength enhancer according to the above item 1 or 2.

4.構成成分(1)が、更にαメチル基不含有カチオン性ビニルモノマー(b’)を含む、前記項1〜3のいずれかの紙力増強剤。 4. The paper strength enhancer according to any one of Items 1 to 3, wherein the component (1) further contains an α-methyl group-free cationic vinyl monomer (b').

5.(b’)成分が、第3級アミノ基含有アクリレート、第3級アミノ基含有アクリルアミド、第4級塩構造含有アクリレート、及び第4級塩構造含有アクリルアミドからなる群より選ばれる少なくとも一種である、前記項4の紙力増強剤。 5. The component (b') is at least one selected from the group consisting of a tertiary amino group-containing acrylate, a tertiary amino group-containing acrylamide, a quaternary salt structure-containing acrylate, and a quaternary salt structure-containing acrylamide. Item 4 The paper strength enhancer.

6.構成成分(1)における(b’)成分の比率が0.1〜3モル%である、前記項4又は5の紙力増強剤。 6. Item 4. The paper strength enhancer according to Item 4 or 5, wherein the ratio of the component (b') to the component (1) is 0.1 to 3 mol%.

7.(c)成分が不飽和カルボン酸を含む、前記項1〜6のいずれかの紙力増強剤。 7. (C) The paper strength enhancer according to any one of Items 1 to 6, wherein the component contains an unsaturated carboxylic acid.

8.不飽和カルボン酸がαメチル基不含有不飽和カルボン酸を含む、前記項7の紙力増強剤。 8. Item 7. The paper strength enhancer according to Item 7, wherein the unsaturated carboxylic acid contains an unsaturated carboxylic acid containing no α-methyl group.

9.αメチル基不含有不飽和カルボン酸がαメチル基不含有不飽和モノカルボン酸を含み、かつその占有比率が50モル%以上である、前記項8の紙力増強剤。 9. Item 8. The paper strength enhancer according to Item 8, wherein the α-methyl group-free unsaturated carboxylic acid contains an α-methyl group-free unsaturated monocarboxylic acid, and the occupancy ratio thereof is 50 mol% or more.

10.αメチル基不含有不飽和モノカルボン酸がアクリル酸及び/又はその塩を含む、前記項9の紙力増強剤。 10. Item 9. The paper strength enhancer according to Item 9, wherein the α-methyl group-free unsaturated monocarboxylic acid contains acrylic acid and / or a salt thereof.

11.構成成分(1)が更に架橋性モノマー(d)を含む、前記項1〜10のいずれかの紙力増強剤。 11. The paper strength enhancer according to any one of Items 1 to 10, wherein the component (1) further contains a crosslinkable monomer (d).

12.(d)成分が、N,N−ジメチルアクリルアミド及びメチレンビスアクリルアミドからなる群より選ばれる少なくとも一種を含む、前記項11の紙力増強剤。 12. Item (11) The paper strength enhancer according to Item 11, wherein the component (d) contains at least one selected from the group consisting of N, N-dimethylacrylamide and methylenebisacrylamide.

13.構成成分(1)における(d)成分の比率が0.01〜1モル%である、前記項11又は12の紙力増強剤。 13. Item 12. The paper strength enhancer according to Item 11 or 12, wherein the ratio of the component (d) to the component (1) is 0.01 to 1 mol%.

14.構成成分(1)が更に連鎖移動性ビニルモノマー(e)を含む、前記項1〜13のいずれかの紙力増強剤。 14. The paper strength enhancer according to any one of Items 1 to 13, wherein the component (1) further contains a chain transfer vinyl monomer (e).

15.(e)成分が(メタ)アリルスルホン酸塩を含む、前記項14の紙力増強剤。 15. Item 14. The paper strength enhancer according to Item 14, wherein the component (e) contains (meth) allyl sulfonate.

16.構成成分(1)における(e)成分の比率が0.05〜2モル%である、前記項14又は15の紙力増強剤。 16. Item 14. The paper strength enhancer according to Item 14 or 15, wherein the ratio of the component (e) to the component (1) is 0.05 to 2 mol%.

17.前記項1〜16のいずれかの紙力増強剤を、無機填料を対パルプ濃度で10〜50重量%含有する抄紙系内に添加することを特徴とする、高灰分紙の製造方法。 17. A method for producing a high ash separation paper, which comprises adding the paper strength enhancer according to any one of Items 1 to 16 into a papermaking system containing an inorganic filler in an amount of 10 to 50% by weight based on pulp.

18.無機填料が、タルク、カオリン及び炭酸カルシウムからなる群より選ばれる少なくとも一種である、前記項17の高灰分紙の製造方法。 18. Item 17. The method for producing a high ash separation paper according to Item 17, wherein the inorganic filler is at least one selected from the group consisting of talc, kaolin and calcium carbonate.

19.前記項17又は18の高灰分紙の製造方法で得られる高灰分紙。 19. The high ash separation paper obtained by the method for producing a high ash separation paper according to Item 17 or 18.

20.紙中灰分が10重量%以上である、前記項19の高灰分紙。 20. Item 19. The high ash separation paper according to Item 19, wherein the ash content in the paper is 10% by weight or more.

本発明に係る紙力増強剤は、無機填料、特に炭酸カルシウムを多く含むパルプスラリーに適用しても、パルプに定着しやすい。また紙力増強効果も良好であり、かつ成紙の地合の乱れも少ない。かかる効果は、古紙パルプスラリーを用いた場合も同様である。 The paper strength enhancer according to the present invention is easily fixed to pulp even when applied to an inorganic filler, particularly a pulp slurry containing a large amount of calcium carbonate. In addition, the effect of enhancing the paper strength is good, and the texture of the finished paper is less disturbed. This effect is the same when the used paper pulp slurry is used.

また、本発明に係る紙力増強剤は、無機填料の表面処理剤としても利用でき、得られた被覆無機填料を用いた場合にも、無機填料の過度の凝集を抑制できるため、本発明の紙力増強剤を添加した紙は、紙力(引張強さ、内部強度)に優れ、かつ地合の乱れも少ない。 Further, the paper strength enhancer according to the present invention can also be used as a surface treatment agent for an inorganic filler, and even when the obtained coated inorganic filler is used, excessive aggregation of the inorganic filler can be suppressed. Paper to which a paper strength enhancer has been added has excellent paper strength (tensile strength, internal strength) and is less likely to have a texture disorder.

Fig.1とFig.2はいずれもアクリルアミドとαメチル基含有カチオン性ビニルモノマーからなるポリアクリルアミドの模式図であり、前者はαメチル基含有カチオン性ビニルモノマーユニットが遍在化している様子を、後者は当該ユニットが局在化している様子を示す。Fig. 1 and Fig. 2 is a schematic diagram of polyacrylamide composed of acrylamide and an α-methyl group-containing cationic vinyl monomer. The former shows that the α-methyl group-containing cationic vinyl monomer unit is ubiquitous, and the latter shows that the unit is the station. Shows how it is present. アクリルアミドとジメチルアミノエチルメタクリレートからなるポリアクリルアミドのH−NMRスペクトルの0.9ppm〜1.35ppmの範囲において、該ジメチルアミノエチルメタクリレートが有するαメチル基に帰属する高磁場側吸収帯A(signal A)と低磁場側吸収帯B(signal B)が出現していることを示す模式図である。High magnetic field side absorption band A (signal A) attributed to the α-methyl group of the dimethylaminoethyl methacrylate in the range of 0.9 ppm to 1.35 ppm of the 1 H-NMR spectrum of polyacrylamide composed of acrylamide and dimethylaminoethyl methacrylate. ) And the low magnetic field side absorption band B (signal B) are shown in the schematic diagram. 図2において、Signal Aよりも高磁場側にピークが出現しない場合の1H−NMRスペクトルの模式図である。FIG. 2 is a schematic diagram of a 1H-NMR spectrum when a peak does not appear on the higher magnetic field side than Signal A. 同じ両性ポリアクリルアミドを添加して調製した成紙1及び成紙2の紙中灰分率及び比引張強さの関係図である。It is a relationship diagram of the ash content ratio and the specific tensile strength in the paper 1 and the paper 2 prepared by adding the same amphoteric polyacrylamide.

本発明の紙力増強剤をなす両性ポリアクリルアミドは、所定の要件〔1〕、〔2〕、〔3〕、〔4〕及び〔5〕を全て充足する点に特徴がある。 The amphoteric polyacrylamide forming the paper strength enhancer of the present invention is characterized in that it satisfies all of the predetermined requirements [1], [2], [3], [4] and [5].

要件〔1〕は、該両性ポリアクリルアミドが、その構成成分(1)にアクリルアミド(a)(以下、成分ともいう。)、αメチル基含有カチオン性ビニルモノマー(b)(以下、(b)成分ともいう。)、アニオン性ビニルモノマー(c)以下、(c)成分ともいう。)を含むことを規定する。 The requirement [1] is that the amphoteric polyacrylamide contains acrylamide (a) (hereinafter, also referred to as a component) and an α-methyl group-containing cationic vinyl monomer (b) (hereinafter, (b) component) as its constituent component (1). Also referred to as a component (c) below the anionic vinyl monomer (c). ) Is included.

本発明では(a)成分としてアクリルアミドを用いる。これは、メタクリルアミドに比べて、本発明に係る両性ポリアクリルアミドの紙力増強効果により寄与するからである。 In the present invention, acrylamide is used as the component (a). This is because the amphoteric polyacrylamide according to the present invention contributes more to the paper strength enhancing effect as compared with methacrylamide.

構成成分(1)における(a)成分の比率は特に限定されないが、本発明に係る両性ポリアクリルアミドの紙力増強効果が優れ、更に成紙の地合が乱れるのを抑制する効果を確保する観点より、通常55〜97.8モル%程度、好ましくは70〜97モル%程度、より好ましくは80〜95モル%程度である。 The ratio of the component (a) to the constituent components (1) is not particularly limited, but the viewpoint of ensuring the effect of enhancing the paper strength of the amphoteric polyacrylamide according to the present invention and further suppressing the texture of the grown paper from being disturbed. More usually, it is about 55 to 97.8 mol%, preferably about 70 to 97 mol%, and more preferably about 80 to 95 mol%.

(b)成分としては、αメチル基を含有するカチオン性ビニルモノマーであれば特に限定されず、各種公知のものを使用できる。ここに「αメチル基」とは、ビニル基及びカチオン性官能基を有するモノマーにおいて、該ビニル基のα炭素に結合したメチル基を意味する。 The component (b) is not particularly limited as long as it is a cationic vinyl monomer containing an α-methyl group, and various known components can be used. Here, the "α-methyl group" means a methyl group bonded to the α-carbon of the vinyl group in a monomer having a vinyl group and a cationic functional group.

Figure 0006897227
Figure 0006897227

(b)成分としては、例えば、第3級アミノ基含有メタクリレート、第3級アミノ基含有メタクリルアミド、第4級塩構造含有メタクリレート、及び第4級塩構造含有メタクリルアミドからなる群より選ばれる少なくとも一種が挙げられる。後者化合物は、前者と四級化剤との反応によって得られる。該第3級アミノ基含有メタクリレート及び第3級アミノ基含有メタクリルアミドの具体例としては、ジメチルアミノエチルメタアクリレート、ジエチルアミノエチルメタアクリレート、ジメチルアミノプロピルメタアクリルアミド及びジエチルアミノプロピルメタアクリルアミド等が挙げられる。また、該四級化剤としては、例えば、メチルクロライド、ベンジルクロライド、ジメチル硫酸及びエピクロロヒドリン等が挙げられる。 The component (b) is at least selected from the group consisting of, for example, a tertiary amino group-containing methacrylate, a tertiary amino group-containing methacrylamide, a quaternary salt structure-containing methacrylate, and a quaternary salt structure-containing methacrylamide. There is one kind. The latter compound is obtained by reacting the former with a quaternizing agent. Specific examples of the tertiary amino group-containing methacrylate and the tertiary amino group-containing methacrylamide include dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminopropyl metaacrylamide, diethylaminopropyl metaacrylamide and the like. Examples of the quaternizing agent include methyl chloride, benzyl chloride, dimethyl sulfate, epichlorohydrin and the like.

また、本発明においては、構成成分(1)に、更に各種公知のαメチル基不含有カチオン性ビニルモノマー(b’)を含めることができる。具体的には、第3級アミノ基含有アクリレート及び第3級アミノ基含有アクリルアミドとそれぞれ四級化剤との反応によって得られる第4級塩構造含有アクリレート及び第4級塩構造含有アクリルアミドが挙げられる。該第3級アミノ基含有アクリレート及び第3級アミノ基含有アクリルアミドとしては、例えば、ジメチルアミノエチルアクリレート、ジエチルアミノエチルアクリレート、ジメチルアミノプロピルアクリルアミド及びジエチルアミノプロピルアクリルアミド等が挙げられる。該四級化剤としては前記したものが挙げられる。 Further, in the present invention, various known α-methyl group-free cationic vinyl monomers (b') can be further included in the component (1). Specific examples thereof include a quaternary salt structure-containing acrylate and a quaternary salt structure-containing acrylamide obtained by reacting a tertiary amino group-containing acrylate and a tertiary amino group-containing acrylamide with a quaternary agent, respectively. .. Examples of the tertiary amino group-containing acrylate and the tertiary amino group-containing acrylamide include dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminopropyl acrylamide and diethyl aminopropyl acrylamide. Examples of the quaternizing agent include those described above.

構成成分(1)における(b’)成分の比率は特に限定されないが、本発明に係る両性ポリアクリルアミドの紙力増強効果の観点より、通常3モル%未満、好ましくは2モル%未満、より好ましくは1モル%未満である。 The ratio of the component (b') to the component (1) is not particularly limited, but is usually less than 3 mol%, preferably less than 2 mol%, more preferably from the viewpoint of the paper strength enhancing effect of the amphoteric polyacrylamide according to the present invention. Is less than 1 mol%.

なお、(b’)成分を用いずに(b)成分のみを用いるほうが、本発明に係る両性ポリアクリルアミドのパルプに対する定着性や紙力増強効果の点で好ましい。これは、そのようにして得られる両性ポリアクリルアミドが分子間の会合による粒子化を生じやすいことによって、パルプ繊維により定着するためであると考えられる。 It is preferable to use only the component (b) without using the component (b') in terms of the fixability of the amphoteric polyacrylamide according to the present invention to pulp and the effect of enhancing the paper strength. It is considered that this is because the amphoteric polyacrylamide thus obtained is likely to be granulated by intermolecular association and thus fixed by the pulp fibers.

(c)成分としては、分子内にアニオン性基を有するビニルモノマーであれば各種公知のものを特に制限なく使用できる。具体的には、不飽和カルボン酸や、不飽和スルホン酸が挙げられる。 As the component (c), any known vinyl monomer having an anionic group in the molecule can be used without particular limitation. Specific examples thereof include unsaturated carboxylic acids and unsaturated sulfonic acids.

不飽和カルボン酸は、αメチル基不含有不飽和カルボン酸と、αメチル基含有不飽和カルボン酸に分類できる。前者としては、例えば、アクリル酸、イタコン酸、マレイン酸、無水マレイン酸及びフマル酸等が挙げられる。後者としては、例えば、メタクリル酸及びクロトン酸等が挙げられる。これらは塩を形成したものであっても良い。塩を形成する種としては、ナトリウム塩及びカリウム塩等のアルカリ金属塩や、トリメチルアミン及びトリブチルアミン等のアミン類、アンモニア等が挙げられる。これらの中でも、特に紙力増強効果が優れ、更に成紙の地合が乱れるのを抑制する観点より、αメチル基不含有不飽和カルボン酸(塩)が好ましく、アクリル酸及び/又はその塩がより好ましい。 Unsaturated carboxylic acids can be classified into α-methyl group-unsaturated carboxylic acids and α-methyl group-containing unsaturated carboxylic acids. Examples of the former include acrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid and the like. Examples of the latter include methacrylic acid and crotonic acid. These may be in the form of salts. Examples of the species forming the salt include alkali metal salts such as sodium salt and potassium salt, amines such as trimethylamine and tributylamine, and ammonia. Among these, α-methyl group-free unsaturated carboxylic acid (salt) is preferable, and acrylic acid and / or a salt thereof is particularly preferable from the viewpoint of excellent paper strength enhancing effect and further suppressing the texture of the grown paper from being disturbed. More preferred.

不飽和スルホン酸としては、例えば、ビニルスルホン酸、スチレンスルホン酸及び2−アクリルアミド−2−メチルプロパンスルホン酸や、それらの塩等が挙げられる。 Examples of unsaturated sulfonic acids include vinyl sulfonic acid, styrene sulfonic acid, 2-acrylamide-2-methylpropane sulfonic acid, and salts thereof.

αメチル基不含有不飽和カルボン酸に占めるαメチル基不含有不飽和モノカルボン酸(好ましくはアクリル酸及び/又はその塩)の比率を50モル%以上とした場合、紙力増強効果及び地合乱れ抑制効果が良好となる傾向にある。 When the ratio of the α-methyl group-free unsaturated monocarboxylic acid (preferably acrylic acid and / or a salt thereof) to the α-methyl group-free unsaturated carboxylic acid is 50 mol% or more, the paper strength enhancing effect and the texture The turbulence suppression effect tends to be good.

構成成分(1)には、本発明に係る両性ポリアクリルアミドの分子量を大きくし、その紙力増強効果を高める目的で、架橋性モノマー(d)(以下、(d)成分ともいう。)を含めてよい。(d)成分としては、ポリアクリルアミドの製造に用い得る架橋性モノマーであれば各種公知のものを特に制限なく使用できる。例えば、アリルアクリレート、ジエチレングリコールモノアクリレート、N,N−ジメチルアクリルアミド等の1官能モノマー;エチレングリコールジアクリレート、ジアリルアミン、N−メチロールアクリルアミド、メチレンビスアクリルアミド等の2官能ビニルモノマー;トリアリルイソシアネート等の3官能ビニルモノマー;テトラアリルオキシエタン等の4官能性ビニルモノマー等が挙げられる。これらの中でも、目的とする両性ポリアクリルアミドに分岐構造及び/又は架橋構造を導入しやすく、その高分子量化を達成し易いことから、前記1官能モノマー及び/又は2官能モノマーが好ましく、特にN,N−ジメチルアクリルアミド及びメチレンビスアクリルアミドからなる群より選ばれる少なくとも一種を含むことが好ましく、N,N−ジメチルアクリルアミドを含むことがより好ましい。 The component (1) includes a crosslinkable monomer (d) (hereinafter, also referred to as a component (d)) for the purpose of increasing the molecular weight of the amphoteric polyacrylamide according to the present invention and enhancing the paper strength enhancing effect thereof. It's okay. As the component (d), various known crosslinkable monomers that can be used for producing polyacrylamide can be used without particular limitation. For example, monofunctional monomers such as allyl acrylate, diethylene glycol monoacrylate, N, N-dimethylacrylamide; bifunctional vinyl monomers such as ethylene glycol diacrylate, diallylamine, N-methylolacrylamide, methylenebisacrylamide; trifunctionals such as triallylisocyanate. Vinyl monomer; Examples thereof include a tetrafunctional vinyl monomer such as tetraallyloxyethane. Among these, the monofunctional monomer and / or the bifunctional monomer are preferable, and particularly N, because it is easy to introduce a branched structure and / or a crosslinked structure into the target amphoteric polyacrylamide and to easily achieve a high molecular weight thereof. It preferably contains at least one selected from the group consisting of N-dimethylacrylamide and methylenebisacrylamide, and more preferably contains N, N-dimethylacrylamide.

構成成分(1)における(d)成分の比率は特に限定されないが、本発明に係る両性ポリアクリルアミドをゲル化させることなく高分子量化させ、前記ポリアクリルアミドのパルプに対する定着性、紙力増強効果に優れ、更に成紙の地合が乱れるのを抑制する観点より、通常、0.01〜1モル%程度、好ましくは0.02〜0.8モル%程度、より好ましくは0.05〜0.6モル%程度である。 The ratio of the component (d) to the constituent components (1) is not particularly limited, but the amphoteric polyacrylamide according to the present invention is increased in molecular weight without gelation, and the polyacrylamide has an effect of enhancing the fixability and paper strength on pulp. From the viewpoint of being excellent and further suppressing the texture of the grown paper from being disturbed, it is usually about 0.01 to 1 mol%, preferably about 0.02 to 0.8 mol%, more preferably 0.05 to 0. It is about 6 mol%.

構成成分(1)には、各種公知の連鎖移動性ビニルモノマー(e)(以下、(e)成分ということがある。)を含めてよい。(e)成分を用いることにより、本発明に係る両性ポリアクリルアミドをゲル化させることなく高分子量化させることができるとともに、その水溶液を低粘度化させることができる。また、該両性ポリアクリルアミドのパルプに対する定着性や、紙力増強効果、成紙の地合いが乱れるのを抑制する効果も良好になる。(e)成分としては、(メタ)アリルスルホン酸塩(即ち、アリルスルホン酸塩及び/又はメタリルスルホン酸塩)が挙げられ、塩を形成する種としては、ナトリウム塩及びカリウム塩等のアルカリ金属塩が挙げられる。 The component (1) may include various known chain transfer vinyl monomers (e) (hereinafter, may be referred to as the component (e)). By using the component (e), the amphoteric polyacrylamide according to the present invention can be made to have a high molecular weight without gelation, and the aqueous solution thereof can be made to have a low viscosity. In addition, the fixability of the amphoteric polyacrylamide to pulp, the effect of enhancing the paper strength, and the effect of suppressing the texture of the finished paper from being disturbed are also improved. Examples of the component (e) include (meth) allyl sulfonate (that is, allyl sulfonate and / or methallyl sulfonate), and examples of the salt-forming species include alkalis such as sodium salt and potassium salt. Metal salts can be mentioned.

構成成分(1)における(e)成分の比率は特に限定されないが、本発明に係る両性ポリアクリルアミドをゲル化させることなく高分子量化し、かつ前記ポリアクリルアミドのパルプに対する定着性や、紙力増強効果が優れ、及び成紙の地合いが乱れるのを抑制する効果を確保する観点より、通常、0.1〜2モル%程度、好ましくは0.15〜1モル%程度、より好ましくは0.2〜0.8モル%程度である。 The ratio of the component (e) to the constituent components (1) is not particularly limited, but the amphoteric polyacrylamide according to the present invention has a high molecular weight without gelation, and the polyacrylamide has a fixing property to pulp and an effect of enhancing paper strength. Is excellent, and from the viewpoint of ensuring the effect of suppressing the texture of the grown paper from being disturbed, it is usually about 0.1 to 2 mol%, preferably about 0.15 to 1 mol%, more preferably about 0.2 to 1. It is about 0.8 mol%.

構成成分(1)には、(a)成分〜(e)成分と反応可能な他のモノマーを更に含めてよく、例えば、(メタ)アクリル酸メチル、(メタ)アクリル酸エチル、(メタ)アクリル酸n−プロピル、(メタ)アクリル酸iso−プロピル、(メタ)アクリル酸n−ブチル、(メタ)アクリル酸iso−ブチル、(メタ)アクリル酸2−エチルヘキシル、(メタ)アクリル酸ステアリル等の(メタ)アクリル酸アルキルエステルや、アクリロニトリル、スチレン類、酢酸ビニル、メチルビニルエーテル等のノニオン性ビニルモノマーが挙げられる。なお、該(メタ)アクリル酸アルキルエステルのアルキル基の炭素数は特に限定されないが、通常1〜8程度である。また、前記構成成分におけるノニオン性ビニルモノマーの比率も特に限定されないが、通常は構成成分(1)を100モル%とした場合において、通常10モル%以下、好ましくは5モル%以下である。 The component (1) may further contain other monomers capable of reacting with the components (a) to (e), for example, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic. N-propyl acid, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, etc. Examples thereof include acrylic acid alkyl esters (meth) and nonionic vinyl monomers such as acrylonitrile, styrenes, vinyl acetate, and methyl vinyl ether. The number of carbon atoms of the alkyl group of the (meth) acrylic acid alkyl ester is not particularly limited, but is usually about 1 to 8. Further, the ratio of the nonionic vinyl monomer in the constituent component is not particularly limited, but usually, when the constituent component (1) is 100 mol%, it is usually 10 mol% or less, preferably 5 mol% or less.

要件〔2〕は、構成成分(1)における(b)成分の比率が1〜15モル%であり、かつ、(c)成分の比率が1〜10モル%であることを規定する。 Requirement [2] stipulates that the ratio of the component (b) in the component (1) is 1 to 15 mol% and the ratio of the component (c) is 1 to 10 mol%.

(b)成分の比率が1モル%よりも小さいと、本発明に係る両性ポリアクリルアミドのパルプに対する定着性や、紙力増強効果が不十分となる傾向にある。また、15モル%を超えると、該両性ポリアクリルアミドの凝集性が強くなり過ぎ、成紙の地合いが乱れる傾向にある。更に前記同様の観点より、(b)成分の比率は、好ましくは2〜12モル%程度、より好ましくは3〜10モル%程度である。 When the ratio of the component (b) is smaller than 1 mol%, the fixability of the amphoteric polyacrylamide according to the present invention to pulp and the effect of enhancing the paper strength tend to be insufficient. On the other hand, if it exceeds 15 mol%, the cohesiveness of the amphoteric polyacrylamide becomes too strong, and the texture of the finished paper tends to be disturbed. Further, from the same viewpoint as described above, the ratio of the component (b) is preferably about 2 to 12 mol%, more preferably about 3 to 10 mol%.

(c)成分の比率が1モル%より小さいと、本発明に係る両性ポリアクリルアミドのパルプに対する定着性や、紙力増強効果が不十分となる傾向にある。また、10モル%を超えると、該両性ポリアクリルアミドの凝集性が強くなり過ぎ、成紙の地合いが乱れる傾向にある。更に前記同様の観点より、(c)成分の比率は、好ましくは1〜9モル%程度、より好ましくは2〜8モル%程度である。 When the ratio of the component (c) is smaller than 1 mol%, the fixability of the amphoteric polyacrylamide according to the present invention to pulp and the effect of enhancing the paper strength tend to be insufficient. On the other hand, if it exceeds 10 mol%, the cohesiveness of the amphoteric polyacrylamide becomes too strong, and the texture of the finished paper tends to be disturbed. Further, from the same viewpoint as described above, the ratio of the component (c) is preferably about 1 to 9 mol%, more preferably about 2 to 8 mol%.

要件〔3〕は、本発明に係る両性ポリアクリルアミドのパラメータを定めたものである。具体的には、該両性ポリアクリルアミドのH−NMRスペクトルには、0.9ppm〜1.35ppmの範囲に前記(b)成分のαメチル基に帰属する高磁場側吸収帯A(以下、シグナルAという。)と低磁場側吸収帯B(以下、シグナルBという。)とが出現する。そして、該吸収帯Aの面積(As)及び該吸収帯Bの面積(Bs)の合計面積に対する該吸収帯Aの面積(As)の比率[As/(As+Bs)]が10〜35%である点に特徴がある。なお、該両性ポリアクリルアミドは高分子化合物であるため、シグナルAとシグナルBはいずれもブロードな裾を有する山形の形状となる。 Requirement [3] defines the parameters of the amphoteric polyacrylamide according to the present invention. Specifically, in the 1 H-NMR spectrum of the amphoteric polyacrylamide, the high magnetic field side absorption band A (hereinafter, signal) attributed to the α-methyl group of the component (b) in the range of 0.9 ppm to 1.35 ppm. A) and the low magnetic field side absorption band B (hereinafter referred to as signal B) appear. The ratio [As / (As + Bs)] of the area (As) of the absorption band A to the total area of the area (As) of the absorption band A and the area (Bs) of the absorption band B is 10 to 35%. It is characterized by points. Since the amphoteric polyacrylamide is a polymer compound, both signal A and signal B have a chevron shape with a broad hem.

ここに、前記ケミカルシフトの範囲(0.9ppm〜1.35ppm)は、内部標準物質として3−(トリメチルシリル)−1−プロパンスルホン酸ナトリウム(DSS)を使用した場合の数値である。 Here, the range of the chemical shift (0.9 ppm to 1.35 ppm) is a numerical value when 3- (trimethylsilyl) -1-propanesulfonate sodium (DSS) is used as the internal standard substance.

また、前記ケミカルシフトの範囲(0.9ppm〜1.35ppm)は本出願人が自発的に定めた範囲であるが、図2で参照されるように、その上限値(1.35ppm)は、シグナルBの左裾側の極小点(local minimum)を目安に設定した。また、該シグナルBの右裾側の極小点を境として、シグナルAの面積AsとシグナルBの面積Bsとが区画される。また、前記ケミカルシフト範囲の下限値(0.9ppm)は、シグナルAよりも高磁場側に更にピークが出現する場合には(図2参照)は該シグナルAの右裾側の極小点を目安に設定した。但し、シグナルAよりも高磁場側にピークが出現しない場合においても、該下限値は0.9ppmとする。この場合、図3で示すように、該シグナルAの右裾とNMRスペクトルのベースラインとの接点(a point of contact)が概ね0.9ppm付近となる。 Further, the range of the chemical shift (0.9 ppm to 1.35 ppm) is a range voluntarily determined by the applicant, but as referred to in FIG. 2, the upper limit value (1.35 ppm) is set. The minimum point on the left hem side of signal B was set as a guide. Further, the area As of the signal A and the area Bs of the signal B are partitioned by the minimum point on the right hem side of the signal B. The lower limit of the chemical shift range (0.9 ppm) is set to the minimum point on the right hem side of the signal A when a peak appears on the higher magnetic field side than the signal A (see FIG. 2). Set to. However, even when a peak does not appear on the higher magnetic field side than the signal A, the lower limit is 0.9 ppm. In this case, as shown in FIG. 3, the contact point (a point of contact) between the right hem of the signal A and the baseline of the NMR spectrum is approximately 0.9 ppm.

シグナルAとBはいずれも、本発明に係る両性ポリアクリルアミドを構成する前記(b)成分のαメチル基に固有の吸収帯である。そして、該両性ポリアクリルアミドの分子鎖上で前記(b)成分のユニットがより連続し(局在化し)、そのαメチル基におけるプロトンがより隣り合う環境に置かれると、シグナルAの相対強度は大きくなり、シグナルBの相対強度は小さくなる。逆に、該両性ポリアクリルアミドの分子鎖上で前記(b)成分のユニットがより遍在化し、そのαメチル基におけるプロトンが隣接しないような環境に置かれると、シグナルAの相対強度は小さくなり、シグナルBの相対強度は大きくなる。 Both signals A and B are absorption bands peculiar to the α-methyl group of the component (b) constituting the amphoteric polyacrylamide according to the present invention. Then, when the unit of the component (b) is more continuous (localized) on the molecular chain of the amphoteric polyacrylamide and the protons at its α-methyl group are placed in a more adjacent environment, the relative intensity of the signal A becomes higher. As it increases, the relative intensity of signal B decreases. On the contrary, when the unit of the component (b) is more ubiquitous on the molecular chain of the amphoteric polyacrylamide and is placed in an environment where the protons at the α-methyl group are not adjacent to each other, the relative intensity of the signal A becomes small. , The relative intensity of signal B increases.

よって、シグナルAとBの全面積におけるシグナルAの面積の比率[As/(As+Bs)]は、これが小さいほど本発明に係る両性ポリアクリルアミドの分子鎖上にカチオン性部位が遍在化していることを意味する。 Therefore, the smaller the ratio of the area of signal A to the total area of signals A and B [As / (As + Bs)], the more ubiquitous the cationic site is on the molecular chain of the amphoteric polyacrylamide according to the present invention. Means.

前記比率[As/(As+Bs)]は、市販のH−NMR測定機を用いて本発明に係る両性ポリアクリルアミドのH−NMRスペクトルを測定し、前記した区画手順に従いAsとBsの積分比を夫々求めることによって、算出可能である。 For the ratio [As / (As + Bs)], the 1 H-NMR spectrum of the amphoteric polyacrylamide according to the present invention is measured using a commercially available 1 H-NMR measuring machine, and the integral ratio of As and Bs is determined according to the above-mentioned partitioning procedure. Can be calculated by finding each.

本発明に係る両性ポリアクリルアミドは、特許文献1に記載の発明とは異なり、高灰分紙に適用されるものであり、無機填料、特に炭酸カルシウムを多く含むパルプスラリーの中でパルプ繊維に自己定着させる目的で、前記比率[As/(As+Bs)]は、好ましくは10%以上35%未満程度、より好ましくは12%以上25%未満、より好ましくは15%以上20%未満程度であるのがよい。 Unlike the invention described in Patent Document 1, the amphoteric polyacrylamide according to the present invention is applied to high ash paper, and self-fixes to pulp fibers in a pulp slurry containing a large amount of an inorganic filler, particularly calcium carbonate. The ratio [As / (As + Bs)] is preferably about 10% or more and less than 35%, more preferably about 12% or more and less than 25%, and more preferably about 15% or more and less than 20%. ..

なお、無機填料が多い、即ちパルプ繊維の比率が相対的に少ない抄紙条件下において、カチオン部位が高度に局在化した両性ポリアクリルアミドを用いると、パルプ繊維の凝集が強くなりすぎると考えられる。この点、本発明では、前記面積比[As/(As+Bs)]を、特許文献1に記載されている値よりも相対的に小さく設定し、かつ、後述の粘度条件及び多分散度条件を最適化したことで、所期の効果が奏されると考えられる。 It is considered that the agglomeration of pulp fibers becomes too strong when amphoteric polyacrylamide having a highly localized cation site is used under papermaking conditions in which the amount of inorganic filler is large, that is, the ratio of pulp fibers is relatively small. In this respect, in the present invention, the area ratio [As / (As + Bs)] is set to be relatively smaller than the value described in Patent Document 1, and the viscosity condition and the polydispersity condition described later are optimized. It is thought that the desired effect will be achieved by the conversion.

要件〔4〕は、本発明に係る両性ポリアクリルアミドの水溶液状態における粘度を規定する。本発明に係る両性ポリアクリルアミドは、特許文献1に係る両性ポリアクリルアミドとは異なり、前記面積比[As/(As+Bs)]の値が相対的に小さい。即ち、本発明に係る両性ポリアクリルアミドは、カチオン性部位の局在化がある程度解消されている。その結果、パルプ繊維への自己定着能力が相対的に低下している。更に高灰分紙抄造用のパルプスラリーは無機填料が多く配合されているため、両性ポリアクリルアミドとパルプ繊維との接触点も少ない。そこで本発明では、かかる不足を補う目的で、15重量%水溶液の粘度を2,000〜60,000mPa・sに規定した。こうすることで、本発明の両性ポリアクリルアミドはパルプ繊維と接触しやすくなり、接触点でより多くの水素結合も形成されるため、無機填料を多く含む抄紙条件において、所定の紙力効果を発揮すると考えられる。かかる観点より、該粘度は、好ましくは3,000〜30,000mPa・s程度、より好ましくは4,000〜15,000mPa・s程度である。 Requirement [4] defines the viscosity of the amphoteric polyacrylamide according to the present invention in an aqueous solution state. The amphoteric polyacrylamide according to the present invention is different from the amphoteric polyacrylamide according to Patent Document 1, and the value of the area ratio [As / (As + Bs)] is relatively small. That is, in the amphoteric polyacrylamide according to the present invention, the localization of the cationic site is eliminated to some extent. As a result, the self-fixing ability to pulp fibers is relatively reduced. Furthermore, since the pulp slurry for high ash papermaking contains a large amount of inorganic filler, there are few contact points between the amphoteric polyacrylamide and the pulp fiber. Therefore, in the present invention, the viscosity of the 15 wt% aqueous solution is defined as 2,000 to 60,000 mPa · s for the purpose of compensating for such a shortage. By doing so, the amphoteric polyacrylamide of the present invention can easily come into contact with the pulp fibers, and more hydrogen bonds are formed at the contact points. Therefore, a predetermined paper strength effect is exhibited under papermaking conditions containing a large amount of inorganic filler. It is thought that. From this point of view, the viscosity is preferably about 3,000 to 30,000 mPa · s, more preferably about 4,000 to 15,000 mPa · s.

粘度は各種公知の手段で測定できる。具体的には、細管式粘度計、落球式粘度計、回転式粘度計などが挙げられるが、所定濃度の粘度を直接測定できる点で回転式粘度計が好ましい。測定器具としては、例えば、B型粘度計が挙げられる。測定条件としては、15重量%水溶液、25℃、No.3ローターで6rpm、又はNo.4ローターで6rpmが好ましい。 The viscosity can be measured by various known means. Specific examples thereof include a thin tube viscometer, a falling ball viscometer, and a rotary viscometer, and a rotary viscometer is preferable because it can directly measure the viscosity of a predetermined concentration. Examples of the measuring instrument include a B-type viscometer. The measurement conditions were 15% by weight aqueous solution, 25 ° C., No. 6 rpm with 3 rotors, or No. 6 rpm with 4 rotors is preferable.

要件〔5〕は、本発明に係る両性ポリアクリルアミドの重量平均分子量(Mw)と数平均分子量(Mn)の比率(Mw/Mn)、即ち該両性ポリアクリルアミドの分子量分布の広がり(以下、多分散度ともいう)を規定する。特許文献1に記載の紙力増強剤は、高灰分条件の抄紙に付すと、成紙(高灰分紙)の地合乱れや紙力低下を起こす傾向にあったが、その理由の一つに、該紙力増強剤をなす両性ポリアクリルアミドの分子量分布が相対的に広く、地合い乱れを起こしやすくする高分子量の両性ポリアクリルアミドや、紙力への貢献度が小さい低分子量の両性ポリアクリルアミドの含有量が多いためであると考えた。そこで本発明では、かかる欠点を補う目的で分子量分布(Mw/Mn)を3.5以下に規定した。当該範囲に限定することでパルプ繊維の過凝集を起こし、成紙の地合い乱れを引き起こす高分子量区分の比率と、パルプ繊維への自己定着性が低く、紙力効果への寄与が比較的低い低分子量区分の比率を少なくすることができる。かかる観点より、該比率は3.5以下、好ましくは3以下、より好ましくは2.8以下であるのがよい。また、下限値は通常1以上、好ましくは1.5以上である。 The requirement [5] is the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the amphoteric polyacrylamide according to the present invention, that is, the spread of the molecular weight distribution of the amphoteric polyacrylamide (hereinafter, polydispersity). (Also called degree) is specified. When the paper strength enhancer described in Patent Document 1 is applied to papermaking under high ash content conditions, it tends to cause the formation of unfinished paper (high ash separation paper) to be disturbed and the paper strength to decrease, which is one of the reasons. , Containing high molecular weight amphoteric polyacrylamide, which has a relatively wide molecular weight distribution and is likely to cause texture disturbance, and low molecular weight amphoteric polyacrylamide, which contributes less to paper strength. I thought it was because of the large amount. Therefore, in the present invention, the molecular weight distribution (Mw / Mn) is defined as 3.5 or less for the purpose of compensating for such a defect. By limiting to this range, the ratio of high molecular weight classifications that cause over-aggregation of pulp fibers and cause texture disorder of the finished paper, and the self-fixing property to pulp fibers are low, and the contribution to the paper strength effect is relatively low. The ratio of molecular weight classification can be reduced. From this point of view, the ratio is preferably 3.5 or less, preferably 3 or less, and more preferably 2.8 or less. The lower limit is usually 1 or more, preferably 1.5 or more.

Mw及びMnは、各種公知の手段で測定できるが、いずれもゲルパーミエーションクロマトグラフィー(GPC)法で求めるのが好ましい。 Mw and Mn can be measured by various known means, but it is preferable to obtain both by gel permeation chromatography (GPC) method.

本発明に係る紙力増強剤の製法は特に限定されないが、前記したように、該紙力増強剤をなす両性ポリアクリルアミドがその分子鎖上でカチオン性部位の局在化を制御でき、規定の粘度、分子量分布を充足させる両性ポリアクリルアミドを製造できる方法であれば、各種公知の重合方法(滴下重合法、同時重合法、多段階重合法等)を採用できる。 The method for producing the paper strength enhancer according to the present invention is not particularly limited, but as described above, the amphoteric polyacrylamide forming the paper strength enhancer can control the localization of the cationic site on the molecular chain, and is defined. Various known polymerization methods (dropping polymerization method, simultaneous polymerization method, multi-step polymerization method, etc.) can be adopted as long as it is a method capable of producing an amphoteric polyacrylamide that satisfies the viscosity and molecular weight distribution.

両性ポリアクリルアミドに要件〔3〕、〔4〕及び〔5〕を充足させるには、例えば、該両性ポリアクリルアミドを構成する全ビニルモノマーを複数のモノマー混合物に分割し、一部の混合物中の(b)成分の使用量を多くしてこれらの混合物を順次反応させたり、或いは、該(b)成分を重合反応中のある時点で反応系内に多く加えたりすることによって、重合反応に関与する(b)成分のある程度濃度が高まるような操作を行うのがよい。 In order to satisfy the requirements [3], [4] and [5] for the amphoteric polyacrylamide, for example, the total vinyl monomer constituting the amphoteric polyacrylamide is divided into a plurality of monomer mixtures, and ( b) Participate in the polymerization reaction by increasing the amount of the component used and reacting these mixtures sequentially, or by adding a large amount of the component (b) into the reaction system at a certain point during the polymerization reaction. (B) It is preferable to perform an operation so as to increase the concentration of the component to some extent.

また、本発明に係る紙力増強剤の好ましい製法は、以下の態様である。この態様によれば、本発明に係るその分子鎖上にカチオン性部位がある程度局在化した領域を有する両性ポリアクリルアミドをより確実に得ることが可能になる。 In addition, a preferred method for producing the paper strength enhancer according to the present invention is as follows. According to this aspect, it becomes possible to more reliably obtain an amphoteric polyacrylamide having a region in which a cationic site is localized to some extent on the molecular chain according to the present invention.

即ち、当該態様は、アクリルアミド(a)及びαメチル基含有カチオン性ビニルモノマー(b)を必須成分として含み、かつ該(b)成分の比率が5〜87モル%(好ましくは5〜60モル%、より好ましくは10〜40モル%)であるモノマー混合物(I)を重合する工程(A)と、アクリルアミド(a)及びアニオン性ビニルモノマー(c)を必須成分として含み、かつ該アニオン性ビニルモノマー(c)の比率が1〜20モル%(好ましくは1〜15モル%、より好ましくは1〜10モル%)であるモノマー混合物(II)を重合する工程(B)とを有することを特徴とする。 That is, the embodiment contains acrylamide (a) and an α-methyl group-containing cationic vinyl monomer (b) as essential components, and the ratio of the component (b) is 5 to 87 mol% (preferably 5 to 60 mol%). , More preferably 10 to 40 mol%), the step (A) of polymerizing the monomer mixture (I), and the anionic vinyl monomer containing acrylamide (a) and the anionic vinyl monomer (c) as essential components. It is characterized by having a step (B) of polymerizing a monomer mixture (II) having a ratio of (c) of 1 to 20 mol% (preferably 1 to 15 mol%, more preferably 1 to 10 mol%). To do.

モノマー混合物(I)とモノマー混合物(II)のいずれか一方又は双方には、必要に応じて、αメチル基不含有カチオン性ビニルモノマー(b’)を含めることができる。 Either one or both of the monomer mixture (I) and the monomer mixture (II) may contain an α-methyl group-free cationic vinyl monomer (b'), if necessary.

また、モノマー混合物(I)には、得られる両性ポリアクリルアミドのパルプに対する定着性や、紙力増強効果が優れ、更に成紙の地合が乱れるのを抑制する等の観点より、それぞれに前記アニオン性ビニルモノマー(c)を含めるのが好ましい。 Further, the monomer mixture (I) has excellent fixing property of the obtained amphoteric polyacrylamide to pulp, an effect of enhancing the paper strength, and further suppresses the formation of the paper from being disturbed. It is preferable to include the sex vinyl monomer (c).

また、モノマー混合物(I)とモノマー混合物(II)の一方又は双方には更に架橋性モノマー(d)を含められるが、この(d)成分は別途、工程(A)及び工程(B)の途中で反応系内に添加したり、工程(A)及び工程(B)の一方又は双方が完了した後に反応系内に添加したりすることもできる。 Further, one or both of the monomer mixture (I) and the monomer mixture (II) can further contain the crosslinkable monomer (d), but the component (d) is separately added during the steps (A) and (B). It can be added to the reaction system at the above, or can be added to the reaction system after one or both of the steps (A) and (B) are completed.

また、モノマー混合物(I)とモノマー混合物(II)には、前述と同様の観点より、その一方又は双方に更に連鎖移動性ビニルモノマー(e)を含めるのが好ましい。 Further, it is preferable that the monomer mixture (I) and the monomer mixture (II) further contain the chain transfer vinyl monomer (e) in one or both of them from the same viewpoint as described above.

モノマー混合物(I)における(b)成分以外の組成は特に限定されないが、得られる両性ポリアクリルアミドのパルプに対する定着性や、紙力増強効果が優れ、更に成紙の地合が乱れるのを抑制する等の観点より、モノマー混合物(I)中のモノマー成分の合計割合を100モル%として、通常、(a)成分30〜90モル%程度、(b’)成分0〜15モル%程度、(c)成分0〜40モル%程度、(d)成分0.01〜3モル%程度又は0モル%、及び(e)成分0〜20モル%程度であり、好ましくは(a)成分40〜85モル%程度、(b’)成分0〜10モル%程度、(c)成分0.1〜30モル%程度又は0モル%、(d)成分0.01〜2.5モル%又は0モル%程度、及び(e)成分0.1〜15モル%程度であり、
より好ましくは(a)成分50〜80モル%程度、(b’)成分0〜5モル%程度、(c)成分1〜20モル%程度又は0モル%、(d)成分0.1〜2モル%程度又は0モル%、及び(e)成分0.1〜10モル%程度である。
The composition of the monomer mixture (I) other than the component (b) is not particularly limited, but the obtained amphoteric polyacrylamide has excellent fixing properties to pulp and a paper strength enhancing effect, and further suppresses the texture of the grown paper from being disturbed. From the viewpoint of the above, the total ratio of the monomer components in the monomer mixture (I) is 100 mol%, and usually, the component (a) is about 30 to 90 mol%, the component (b') is about 0 to 15 mol%, and (c). ) Component 0 to 40 mol%, (d) component 0.01 to 3 mol% or 0 mol%, and (e) component 0 to 20 mol%, preferably (a) component 40 to 85 mol. %, (B') component 0 to 10 mol%, (c) component 0.1 to 30 mol% or 0 mol%, (d) component 0.01 to 2.5 mol% or 0 mol% , And (e) component is about 0.1 to 15 mol%.
More preferably, (a) component is about 50 to 80 mol%, (b') component is about 0 to 5 mol%, (c) component is about 1 to 20 mol% or 0 mol%, and (d) component is 0.1 to 2. It is about mol% or 0 mol%, and the component (e) is about 0.1 to 10 mol%.

モノマー混合物(II)における(c)成分以外の組成は特に限定されないが、得られる両性ポリアクリルアミドのパルプに対する定着性や、紙力増強効果が優れ、更に成紙の地合が乱れるのを抑制する等の観点より、モノマー混合物(II)中のモノマー成分の合計割合を100モル%として、通常、(a)成分20〜98.8モル%程度、(b)成分0〜15モル%程度、(b’)成分0〜15モル%程度、(d)成分0.001〜1モル%程度又は0モル%、及び(e)成分0〜1モル%程度であり、好ましくは(a)成分60〜98.8モル%程度、(b)成分0〜10モル%程度、(b’)成分0〜10モル%程度、(d)成分0.01〜0.5モル%程度又は0モル%、及び(e)成分0.01〜0.5モル%程度であり、より好ましくは(a)成分70〜98.8モル%程度、(b)成分0〜5モル%程度、(b’)成分0〜8モル%程度、(d)成分0.1〜0.4モル%程度又は0モル%、及び(e)成分0.01〜0.4モル%程度である。 The composition of the monomer mixture (II) other than the component (c) is not particularly limited, but the obtained amphoteric polyacrylamide has excellent fixing properties to pulp and a paper strength enhancing effect, and further suppresses the texture of the grown paper from being disturbed. From the viewpoints of the above, the total ratio of the monomer components in the monomer mixture (II) is 100 mol%, and usually, the component (a) is about 20 to 98.8 mol%, and the component (b) is about 0 to 15 mol%. b') component 0 to 15 mol%, (d) component 0.001 to 1 mol% or 0 mol%, and (e) component 0 to 1 mol%, preferably component (a) 60 to 1 mol%. About 98.8 mol%, (b) component 0 to 10 mol%, (b') component 0 to 10 mol%, (d) component 0.01 to 0.5 mol% or 0 mol%, and The component (e) is about 0.01 to 0.5 mol%, more preferably the component (a) is about 70 to 98.8 mol%, the component (b) is about 0 to 5 mol%, and the component (b') is 0. It is about 8 mol%, (d) component 0.1-0.4 mol% or 0 mol%, and (e) component 0.01-0.4 mol%.

また、前記要件〔3〕を充足する両性ポリアクリルアミドを収率良く得るためには、モノマー混合物(I)及びモノマー混合物(II)を構成する全モノマーの総モルに対するモノマー混合物(I)のモル比率〔(I)/((I)+(II))〕は通常25モル%以下(好ましくは8〜24モル%程度、より好ましくは10〜22モル%程度)とするのがよい。 Further, in order to obtain an amphoteric polyacrylamide satisfying the above requirement [3] in good yield, the molar ratio of the monomer mixture (I) to the total moles of all the monomers constituting the monomer mixture (I) and the monomer mixture (II). [(I) / ((I) + (II))] is usually 25 mol% or less (preferably about 8 to 24 mol%, more preferably about 10 to 22 mol%).

また、モノマー混合物(I)及びモノマー混合物(II)は、いずれも溶液として使用できる。溶媒としては通常、水が好ましく、メタノール、エタノール、2−プロパノール等の有機溶剤を助溶剤として併用することもできる。また、モノマー混合物(I)及び/又はモノマー混合物(II)が加水分解し易いモノマーを含む場合には、これを防ぐために硫酸を用いることができる。 Moreover, both the monomer mixture (I) and the monomer mixture (II) can be used as a solution. Water is usually preferable as the solvent, and an organic solvent such as methanol, ethanol, or 2-propanol can be used in combination as an auxiliary solvent. When the monomer mixture (I) and / or the monomer mixture (II) contains a monomer that is easily hydrolyzed, sulfuric acid can be used to prevent this.

工程(A)及び工程(B)の重合条件は特に限定されない。例えば、重合温度はいずれも通常50〜100℃程度であり、重合時間はいずれも1〜5時間程度である。また、工程(A)及び/又は工程(B)においては、過硫酸カリウムや過硫酸アンモニウムのような従来公知の重合開始剤や、該開始剤と亜硫酸水素ナトリウムのような還元剤とからなるレドックス系重合開始剤、アゾ系開始剤等の開始剤を使用できる。また、その使用量は特に限定されないが、通常、本発明に係る両性ポリアクリルアミドの全構成モノマーの総重量に対して通常0.01〜2重量%程度であり、好ましくは0.05〜0.5重量%程度である。 The polymerization conditions of the step (A) and the step (B) are not particularly limited. For example, the polymerization temperature is usually about 50 to 100 ° C., and the polymerization time is about 1 to 5 hours. Further, in the step (A) and / or the step (B), a redox system composed of a conventionally known polymerization initiator such as potassium persulfate or ammonium persulfate, or a reducing agent such as the initiator and sodium hydrogen sulfite. Initiators such as polymerization initiators and azo-based initiators can be used. The amount used is not particularly limited, but is usually about 0.01 to 2% by weight, preferably 0.05 to 0% by weight, based on the total weight of all the constituent monomers of the amphoteric polyacrylamide according to the present invention. It is about 5% by weight.

なお、工程(A)においては、モノマー混合物(I)を滴下重合させても、同時重合させても、これらを組み合わせてもよい。但し、重合反応を制御しやすいため、滴下重合が好ましい。 In the step (A), the monomer mixture (I) may be subjected to dropping polymerization, co-polymerization, or a combination thereof. However, dropping polymerization is preferable because it is easy to control the polymerization reaction.

また、工程(B)においても、モノマー混合物(II)を滴下重合させても、同時重合させても、これらを組み合わせてもよい。但し、重合反応を制御しやすいため、同じく滴下重合が好ましい。 Further, also in the step (B), the monomer mixture (II) may be subjected to dropping polymerization, co-polymerization, or a combination thereof. However, since it is easy to control the polymerization reaction, dropping polymerization is also preferable.

また、工程(A)と工程(B)の順序は、両性ポリアクリルアミドの分子鎖上にカチオン性部位がある程度局在化した領域を形成するという目的を達成できる限りにおいて、特に限定されない。例えば、工程(A)を完了させた後に工程(B)を開始したり、工程(B)を完了させた後に工程(A)を開始したりする方法等が挙げられる。また、工程(A)と工程(B)の時間的な間隔は特に制限されず、例えば工程(A)又は工程(B)を完了させた直後にもう一方の工程を開始してもよく、工程(A)又は工程(B)を完了させて一定時間経過した後にもう一方の工程を開始してもよい。また、工程(A)又は工程(B)の開始後、それらが完了する前に同一反応系でもう一方の工程を開始してもよく、この場合はカチオン性部位がある程度遍在化した両性ポリアクリルアミドを得ることが可能になる。 Further, the order of the steps (A) and (B) is not particularly limited as long as the object of forming a region in which the cationic site is localized to some extent on the molecular chain of the amphoteric polyacrylamide can be achieved. For example, a method of starting the step (B) after completing the step (A), a method of starting the step (A) after completing the step (B), and the like can be mentioned. Further, the time interval between the step (A) and the step (B) is not particularly limited, and for example, the other step may be started immediately after the step (A) or the step (B) is completed. The other step may be started after a certain period of time has elapsed after completing the step (A) or the step (B). Alternatively, after the start of step (A) or step (B) and before they are completed, the other step may be started in the same reaction system, in which case amphoteric poly with some ubiquitous cationic sites. It becomes possible to obtain acrylamide.

また開始剤は、例えば、モノマー混合物(I)及び/又はモノマー混合物(II)に予め含めても良いし、含めなくてもよい。含めない場合には、例えば、工程(A)及び工程(B)の双方に亘り、外部より前記開始剤を反応系内に滴下することが挙げられる。この場合、開始剤は水溶液として用いることができる。 The initiator may or may not be included in the monomer mixture (I) and / or the monomer mixture (II) in advance, for example. When not included, for example, the initiator is added dropwise into the reaction system from the outside throughout both the step (A) and the step (B). In this case, the initiator can be used as an aqueous solution.

本発明に係る紙力増強剤の最も好ましい製法は、モノマー混合物(I)を滴下重合させる工程(A)を完了させた後、同一反応系にモノマー混合物(II)を滴下し、重合させる態様である。この態様では、(b)成分を相対的に多く含むモノマー混合物(I)を工程(A)で重合させることによって、ある程度カチオン性部位の密度の大きなポリアクリルアミド前駆体を一旦製造する。次いで、該前駆体の存在下、(b)成分の量が相対的に少ないか或いはゼロのモノマー混合物(II)を重合させることによって、カチオン性部位がある程度局在化した領域を分子鎖上に有する両性ポリアクリルアミドを容易に得ることができる。また、この態様においては、工程(A)と工程(B)の双方に亘り前記開始剤を反応系に滴下するのが好ましい。 The most preferable method for producing the paper strength enhancer according to the present invention is to complete the step (A) of dropping and polymerizing the monomer mixture (I), and then drop and polymerize the monomer mixture (II) into the same reaction system. is there. In this embodiment, the monomer mixture (I) containing a relatively large amount of the component (b) is polymerized in the step (A) to once produce a polyacrylamide precursor having a high density of cationic sites to some extent. Then, in the presence of the precursor, by polymerizing the monomer mixture (II) in which the amount of the component (b) is relatively small or zero, a region in which the cationic moiety is localized to some extent is formed on the molecular chain. An amphoteric polyacrylamide having can be easily obtained. Further, in this embodiment, it is preferable to drop the initiator into the reaction system throughout both the step (A) and the step (B).

本発明に係る両性ポリアクリルアミドのMwは通常、通常500,000〜10,000,000程度、好ましくは1,000,000〜7,000,000程度であり、また、Mnは通常、200,000〜6,000,000程度、好ましくは400,000〜4,000,000程度である。 The Mw of the amphoteric polyacrylamide according to the present invention is usually about 500,000 to 1,000,000, preferably about 1,000,000 to 7,000,000, and the Mn is usually about 200,000. It is about 6,000,000, preferably about 400,000 to 4,000,000.

本発明の紙力増強剤は、前述の両性ポリアクリルアミドを含み、水溶液として利用するのが好ましい。また、その固形分濃度は特に限定されないが、通常、0.01〜2重量%程度である。 The paper strength enhancer of the present invention contains the above-mentioned amphoteric polyacrylamide and is preferably used as an aqueous solution. The solid content concentration is not particularly limited, but is usually about 0.01 to 2% by weight.

本発明の紙力増強剤には、他の紙力剤を含めてよい。具体的には、カチオン化澱粉、両性澱粉などの変性澱粉、カルボキシメチルセルロース、ヒドロキシエチルセルロースなどの変性セルロース、ポリビニルアルコール、尿素ホルムアルデヒド樹脂、メラミンホルムアルデヒド樹脂、ポリアミドポリアミンエピクロルヒドリン、ポリビニルアミン等が挙げられる。かかる他の紙力剤の混合量も特に限定されないが、本発明の紙力増強剤及び他の紙力剤の合計を100重量%として、通常、0.1〜40重量%程度である。 The paper strength enhancer of the present invention may include other paper strength agents. Specific examples thereof include cationized starch, modified starch such as amphoteric starch, modified cellulose such as carboxymethyl cellulose and hydroxyethyl cellulose, polyvinyl alcohol, urea formaldehyde resin, melamine formaldehyde resin, polyamide polyamine epichlorohydrin, polyvinyl amine and the like. The mixing amount of the other paper strengthening agent is not particularly limited, but is usually about 0.1 to 40% by weight, assuming that the total of the paper strength enhancing agent and the other paper strengthening agent of the present invention is 100% by weight.

本発明に係る高灰分紙の製造方法は、本発明の紙力増強剤を、無機填料を対パルプの重量(固形分)で10〜50重量%含有するパルプスラリーに添加し、抄紙することを特徴とする。 The method for producing high ash paper according to the present invention is to add the paper strength enhancer of the present invention to a pulp slurry containing an inorganic filler in an amount of 10 to 50% by weight based on the weight (solid content) of the pulp to make paper. It is a feature.

無機填料としては、例えば、タルク、カオリン及び炭酸カルシウムからなる群より選ばれる少なくとも一種が挙げられる。炭酸カルシウムとしては、重質炭酸カルシウム、軽質炭酸カルシウム等が挙げられる。 Examples of the inorganic filler include at least one selected from the group consisting of talc, kaolin and calcium carbonate. Examples of calcium carbonate include heavy calcium carbonate and light calcium carbonate.

パルプスラリーとしては、クラフトパルプ、サルファイトパルプ等の晒あるいは未晒化学パルプ、砕木パルプ、機械パルプ、サーモメカニカルパルプ等の晒あるいは未晒パルプ、新聞古紙、雑誌古紙、ダンボール古紙、脱墨古紙等の古紙パルプ等が挙げられる。 Examples of pulp slurry include bleached or unbleached chemical pulp such as kraft pulp and sulfite pulp, crushed wood pulp, mechanical pulp, bleached or unbleached pulp such as thermomechanical pulp, used newspaper, used magazine, used cardboard, and deinked used paper. Waste paper pulp and the like.

本発明の紙力増強剤の添加量は特に限定されず、紙やパルプスラリーの種類、抄紙条件によって適宜決定すればよいが、通常は、パルプスラリーの重量(固形分)に対し、紙力増強剤中に含まれる両性ポリアクリルアミドの固形分で通常0.1重量%以上であり、好ましくは0.1〜3重量%程度である。また、パルプスラリーには硫酸アルミニウムやサイズ剤、その他の製紙用添加剤を添加してもよい。 The amount of the paper strength enhancer added of the present invention is not particularly limited and may be appropriately determined depending on the type of paper or pulp slurry and the papermaking conditions, but usually, the paper strength is enhanced with respect to the weight (solid content) of the pulp slurry. The solid content of the amphoteric polyacrylamide contained in the agent is usually 0.1% by weight or more, preferably about 0.1 to 3% by weight. Further, aluminum sulfate, a sizing agent, and other papermaking additives may be added to the pulp slurry.

本発明の高灰分紙は、前述の製造方法で得られる。得られる高灰分紙は、ライナー原紙、中芯原紙、紙管原紙、白板紙、クラフト紙、上質紙、新聞紙等として使用できる。また、該高灰分紙における前記無機填料の含有量は特に限定されないが、通常10重量%以上、好ましくは10〜30重量%程度である。 The high ash separation paper of the present invention can be obtained by the above-mentioned production method. The obtained high ash separation paper can be used as liner base paper, core base paper, paper tube base paper, white paperboard, kraft paper, high-quality paper, newspaper and the like. The content of the inorganic filler in the high ash paper is not particularly limited, but is usually 10% by weight or more, preferably about 10 to 30% by weight.

以下、参照例、実施例及び比較例を挙げて本発明をより具体的に説明するが、本発明はこれら各例に限定されるものではない。尚、各例中、部及び%は特記しない限りすべて重量基準である。各例の物性値は、以下の方法により測定した値である。 Hereinafter, the present invention will be described in more detail with reference to Reference Examples, Examples and Comparative Examples, but the present invention is not limited to each of these examples. In each example, parts and% are all based on weight unless otherwise specified. The physical property values of each example are values measured by the following methods.

実施例1
撹拌機、温度計、還流冷却管、窒素ガス導入管及び3つの滴下ロート(以下、順にロート1、ロート2及びロート3という。)を備えた反応容器にイオン交換水401.4部を仕込み、該イオン交換水に窒素ガスを直接吹き込むことにより該反応容器内の酸素を除去した後、該イオン交換水の温度を90℃に設定した。
次いで、ロート1に、モノマー混合物(I)として、50%アクリルアミド水溶液79.04部、ジメチルアミノエチルメタクリレート24.37部、80%アクリル酸3.99部、N,N−ジメチルアクリルアミド0.18部、メタリルスルホン酸ナトリウム0.292部、62.5%硫酸11.91部及びイオン交換水61.42部からなる水溶液を更に硫酸でpH4.5に調整したものを仕込んだ。
次いで、ロート2に、モノマー混合物(II)として、50%アクリルアミド水溶液386.98部、ジメチルアミノエチルメタクリレート10.44部、75%ジメチルアミノエチルアクリレートのベンジルクロライド4級化物13.27部、80%アクリル酸9.31部、N,N−ジメチルアクリルアミド0.18部、メタリルスルホン酸ナトリウム0.292部、62.5%硫酸5.10部及びイオン交換水231.16部からなる水溶液を更に硫酸でpH4.5に調整したものを仕込んだ。
次いで、ロート3に、過硫酸アンモニウム0.21部及びイオン交換水180部からなる開始剤溶液を仕込んだ。
次いで、ロート1とロート3のコックを同時に開き、前記モノマー混合物(I)の全量及び前記開始剤溶液の半量をそれぞれ2時間かけて滴下させた。その後直ちにロート2のコックを開き、前記モノマー混合物(II)の全量と、該開始剤溶液の残り半量とを2時間かけて滴下させた。
次いで、反応系を90℃で1時間保温した後、更にイオン交換水562部を仕込むことにより、重量平均分子量121万及び粘度8,900mPa・sの両性ポリアクリルアミド(固形分濃度15.0%)を得た。
Example 1
401.4 parts of ion-exchanged water was charged into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen gas introduction tube, and three dropping funnels (hereinafter, referred to as funnel 1, funnel 2 and funnel 3 in this order). After removing oxygen in the reaction vessel by directly blowing nitrogen gas into the ion-exchanged water, the temperature of the ion-exchanged water was set to 90 ° C.
Next, in funnel 1, 79.04 parts of a 50% acrylamide aqueous solution, 24.37 parts of dimethylaminoethyl methacrylate, 3.99 parts of 80% acrylic acid, and 0.18 parts of N, N-dimethylacrylamide were added as a monomer mixture (I). , 0.292 parts of sodium metalylsulfonate, 11.91 parts of 62.5% sulfuric acid and 61.42 parts of ion-exchanged water were further adjusted to pH 4.5 with sulfuric acid.
Next, in funnel 2, as a monomer mixture (II), 386.98 parts of a 50% acrylamide aqueous solution, 10.44 parts of dimethylaminoethyl methacrylate, 13.27 parts of a benzyl chloride quaternized product of 75% dimethylaminoethyl acrylate, 80%. An aqueous solution consisting of 9.31 parts of acrylic acid, 0.18 parts of N, N-dimethylacrylamide, 0.292 parts of sodium metalylsulfonate, 5.10 parts of 62.5% sulfuric acid and 231.16 parts of ion-exchanged water was further added. A mixture adjusted to pH 4.5 with sulfuric acid was charged.
Next, an initiator solution consisting of 0.21 part of ammonium persulfate and 180 parts of ion-exchanged water was charged into the funnel 3.
Next, the cocks of funnel 1 and funnel 3 were opened at the same time, and the entire amount of the monomer mixture (I) and half of the initiator solution were added dropwise over 2 hours, respectively. Immediately thereafter, the cock of the funnel 2 was opened, and the entire amount of the monomer mixture (II) and the other half of the initiator solution were added dropwise over 2 hours.
Next, the reaction system was kept warm at 90 ° C. for 1 hour, and then 562 parts of ion-exchanged water was further charged to obtain an amphoteric polyacrylamide having a weight average molecular weight of 1.21 million and a viscosity of 8,900 mPa · s (solid content concentration: 15.0%). Got

実施例2〜15
モノマー混合物(I)とモノマー混合物(II)及び開始剤溶液を表1に示す組成のものに変更した以外は実施例1と同じ方法で両性ポリアクリルアミド(いずれも固形分濃度15.0%)を得た。
Examples 2 to 15
Amphoteric polyacrylamide (both solid content concentration 15.0%) was applied in the same manner as in Example 1 except that the monomer mixture (I), the monomer mixture (II) and the initiator solution were changed to those having the compositions shown in Table 1. Obtained.

比較例1〜9、11
モノマー混合物(I)とモノマー混合物(II)を表1に示す組成のものに変更した以外は実施例1と同じ方法で両性ポリアクリルアミド(いずれも固形分濃度15.0%)を得た。
Comparative Examples 1-9, 11
An amphoteric polyacrylamide (both having a solid content concentration of 15.0%) was obtained by the same method as in Example 1 except that the monomer mixture (I) and the monomer mixture (II) were changed to those having the compositions shown in Table 1.

比較例10
撹拌機、温度計、還流冷却管、窒素ガス導入管及び3つの滴下ロート(以下、順にロート1、ロート2及びロート3という。)を備えた反応容器にイオン交換水276.2部を仕込み、該イオン交換水に窒素ガスを直接吹き込むことにより該反応容器内の酸素を除去した後、該イオン交換水の温度を90℃に設定した。
次いで、ロート1に、モノマー混合物(I)として、50%アクリルアミド水溶液193.00部、ジメチルアミノエチルメタクリレート40.20部、60%ジメチルアミノエチルメタクリレートのベンジルクロライド4級化物24.20部、80%アクリル酸1.40部、N,N−ジメチルアクリルアミド0.300部、メチレンビスアクリルアミド0.250部、メタリルスルホン酸ナトリウム3.200部、62.5%硫酸19.70部及びイオン交換水168.1部からなる水溶液を更に硫酸でpH4.5に調整したものを仕込んだ。
次いで、ロート2に、モノマー混合物(II)として、50%アクリルアミド水溶液469.00部、80%アクリル酸9.200部、N,N−ジメチルアクリルアミド0.30部、メチレンビスアクリルアミド0.250部、メタリルスルホン酸ナトリウム0.800部及びイオン交換水212.30部からなる水溶液を仕込んだ。
次いで、ロート3に、過硫酸アンモニウム0.6部及びイオン交換水180部からなる開始剤溶液を仕込んだ。
次いで、ロート1とロート3のコックを同時に開き、前記モノマー混合物(I)の全量及び前記開始剤溶液の半量をそれぞれ2時間かけて滴下させた。その後直ちにロート2のコックを開き、前記モノマー混合物(II)の全量と、該開始剤溶液の残り半量とを2時間かけて滴下させた。
次いで、反応系を90℃で1時間保温した後、更にイオン交換水400部を仕込むことにより、重量平均分子量300万及び粘度8,500mPa・sの両性ポリアクリルアミド(固形分濃度20.3%)を得た。本サンプルをイオン交換水にて15.0%に希釈した粘度を測定すると1,200mPa・sであった。
Comparative Example 10
276.2 parts of ion-exchanged water was charged into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen gas introduction tube, and three dropping funnels (hereinafter, referred to as funnel 1, funnel 2 and funnel 3 in this order). After removing oxygen in the reaction vessel by directly blowing nitrogen gas into the ion-exchanged water, the temperature of the ion-exchanged water was set to 90 ° C.
Next, in funnel 1, as a monomer mixture (I), 193.00 parts of 50% acrylamide aqueous solution, 40.20 parts of dimethylaminoethyl methacrylate, 24.20 parts of benzyl chloride quaternized product of 60% dimethylaminoethyl methacrylate, 80%. 1.40 parts of acrylic acid, 0.300 parts of N, N-dimethylacrylamide, 0.250 parts of methylenebisacrylamide, 3.200 parts of sodium metalylsulfonate, 19.70 parts of 62.5% sulfuric acid and 168 parts of ion-exchanged water. . A 1-part aqueous solution was further adjusted to pH 4.5 with sulfuric acid and charged.
Next, in funnel 2, as a monomer mixture (II), 469.00 parts of a 50% acrylamide aqueous solution, 9.200 parts of 80% acrylic acid, 0.30 parts of N, N-dimethylacrylamide, and 0.250 parts of methylenebisacrylamide. An aqueous solution consisting of 0.800 parts of sodium metharylsulfonate and 212.30 parts of ion-exchanged water was charged.
Next, an initiator solution consisting of 0.6 parts of ammonium persulfate and 180 parts of ion-exchanged water was charged into the funnel 3.
Next, the cocks of funnel 1 and funnel 3 were opened at the same time, and the entire amount of the monomer mixture (I) and half of the initiator solution were added dropwise over 2 hours, respectively. Immediately thereafter, the cock of the funnel 2 was opened, and the entire amount of the monomer mixture (II) and the other half of the initiator solution were added dropwise over 2 hours.
Next, the reaction system was kept warm at 90 ° C. for 1 hour, and then 400 parts of ion-exchanged water was further charged to obtain an amphoteric polyacrylamide having a weight average molecular weight of 3 million and a viscosity of 8,500 mPa · s (solid content concentration: 20.3%). Got The viscosity of this sample diluted to 15.0% with ion-exchanged water was measured and found to be 1,200 mPa · s.

実施例及び比較例について、表2には、モノマー混合物(I)又はモノマー混合物(II)中のモノマー成分の合計割合を100モル%にした場合の各成分のモル比率を、表3には、全モノマー成分を100モル%にした場合の各成分のモル比率をそれぞれ表した。 For Examples and Comparative Examples, Table 2 shows the molar ratio of each component when the total ratio of the monomer components in the monomer mixture (I) or the monomer mixture (II) is 100 mol%, and Table 3 shows the molar ratio of each component. The molar ratio of each component when all the monomer components were set to 100 mol% was shown.

表1〜3中の、化合物を表す記号は以下の意味である。
AM:アクリルアミド(分子量71.1)
DM:ジメチルアミノエチルメタクリレート(分子量157.2)
DML:ジメチルアミノエチルメタクリレートのベンジルクロライド4級化物(分子量283.8)
APDM:ジメチルアミノプロピルアクリルアミド(分子量156.2)
DMAEA−BQ:ジメチルアミノエチルアクリレートのベンジルクロライド4級化物(分子量269.8)
IA:イタコン酸(分子量130.1)
AA:アクリル酸(分子量72.1)
DMAA:N,N−ジメチルアクリルアミド(分子量99.1)
MBAA:メチレンビスアクリルアミド(分子量154.2)
SMAS:メタリルスルホン酸ナトリウム(分子量158.2)
APS:過硫酸アンモニウム(分子量228.2)
V−50:2,2’−アゾビス−2−アミジノプロパン 二塩酸塩(分子量271.2)
The symbols representing compounds in Tables 1 to 3 have the following meanings.
AM: Acrylamide (molecular weight 71.1)
DM: Dimethylaminoethyl methacrylate (molecular weight 157.2)
DML: Benzyl chloride quaternary product of dimethylaminoethyl methacrylate (molecular weight 283.8)
APDM: Dimethylaminopropylacrylamide (Molecular Weight 156.2)
DMAEA-BQ: Benzyl chloride quaternary product of dimethylaminoethyl acrylate (molecular weight 269.8)
IA: Itaconic acid (molecular weight 130.1)
AA: Acrylic acid (molecular weight 72.1)
DMAA: N, N-dimethylacrylamide (molecular weight 99.1)
MBAA: Methylenebisacrylamide (molecular weight 154.2)
SMAS: Sodium Metalyl Sulfonate (Molecular Weight 158.2)
APS: Ammonium persulfate (molecular weight 228.2)
V-50: 2,2'-azobis-2-amidinopropane dihydrochloride (molecular weight 271.2)

Figure 0006897227
Figure 0006897227

Figure 0006897227
Figure 0006897227

Figure 0006897227
Figure 0006897227

H−NMRスペクトルの測定>
実施例1〜15及び比較例1〜11の両性ポリアクリルアミド26.7mgと重水(DO)0.8mlとを混合した後、当該混合液に、3−(トリメチルシリル)−1−プロパンスルホン酸ナトリウム(DSS)40.23mgとD2O1.0mlとを混合してなる内部標準液を、マイクロシリンジを用いて1μl滴下し、測定用サンプル(濃度:0.5%)を調製した。
< 1 Measurement of 1 H-NMR spectrum>
After mixing the amphoteric polyacrylamide 26.7mg and heavy water (D 2 O) 0.8 ml of Examples 1 to 15 and Comparative Examples 1 to 11, to the mixture, 3- (trimethylsilyl) -1-propanesulfonic acid An internal standard solution prepared by mixing 40.23 mg of sodium (DSS) and 1.0 ml of D2O was added dropwise by 1 μl using a microsyringe to prepare a measurement sample (concentration: 0.5%).

次いで、当該サンプルを用い、以下の条件下、H−NMRスペクトルを測定した。 Then, using the sample, 1 1 H-NMR spectrum was measured under the following conditions.

NMR測定器:400MR AgilentTechnologies製 400MHz
プローブ:AutoX PFG probe(5mm)
プローブ温度:70℃
測定周波数:399.75MHz
測定溶媒:重水(D2O)
パルスシーケンス:presaturation スタンダードパラメーター使用
積算回数:128回
NMR measuring instrument: 400MR Made by Agent Technologies 400MHz
Probe: AutoX PFG probe (5 mm)
Probe temperature: 70 ° C
Measurement frequency: 399.75 MHz
Measuring solvent: heavy water (D2O)
Pulse sequence: presaturation standard parameter usage integration count: 128 times

<シグナル面積の比率[As/(As+Bs)]の算出>
前記NMR測定器に付属する解析ソフトvNMRJ(Agilent Technologies製)を用い、シグナルの面積<As>及び<Bs>をそれぞれ計算機上で求めた上で、面積の比率[As/(As+Bs)]を算出した。結果を表4に示す。
<Calculation of signal area ratio [As / (As + Bs)]>
Using the analysis software vNMRJ (manufactured by Agilent Technologies) attached to the NMR measuring instrument, the signal areas <As> and <Bs> are calculated on a computer, and then the area ratio [As / (As + Bs)] is calculated. did. The results are shown in Table 4.

<重量平均分子量>
実施例1〜15及び比較例1〜11の両性ポリアクリルアミドについて、以下の条件下、重量平均分子量及び多分散度(Mw/Mn)を測定した。結果を表4に示す。
<Weight average molecular weight>
For the amphoteric polyacrylamides of Examples 1 to 15 and Comparative Examples 1 to 11, the weight average molecular weight and the degree of polydispersity (Mw / Mn) were measured under the following conditions. The results are shown in Table 4.

GPC本体:東ソー(株)製
カラム:東ソー(株)製ガードカラムPWXL1本及びGMPWXL2本(カラム温度40℃。)
溶離液:N/2酢酸緩衝液(N/2酢酸(和光純薬工業(株)製)+N/2酢酸ナトリウム(キシダ化学(株)製)水溶液、pH4.2)
流速:0.8ml/分
検出器:
RALLS法;ビスコテック社製TDA MODEL301(濃度検出器及び90°光散乱検出器及び粘度検出器の温度はそれぞれ40℃に設定)
GPC body: Tosoh Corporation column: Tosoh Corporation guard column PWXL 1 and GMPWXL 2 (column temperature 40 ° C.)
Eluent: N / 2 acetic acid buffer (N / 2 acetic acid (manufactured by Wako Pure Chemical Industries, Ltd.) + N / 2 sodium acetate (manufactured by Kishida Chemical Industries, Ltd.) aqueous solution, pH 4.2)
Flow velocity: 0.8 ml / min Detector:
RALLS method; TDA MODEL301 manufactured by Viscotec (the temperature of the concentration detector, 90 ° light scattering detector, and viscosity detector is set to 40 ° C, respectively).

<粘度>
実施例1〜15及び比較例1〜11の両性ポリアクリルアミドについて、B型粘度計(製品名「ビストメトロン」、芝浦システム社製)を用い、25℃、回転数6rpm、ローターNo.3の条件で粘度を測定した。結果を表4に示す。
<Viscosity>
For the amphoteric polyacrylamides of Examples 1 to 15 and Comparative Examples 1 to 11, a B-type viscometer (product name "Bistometron", manufactured by Shibaura System Co., Ltd.) was used at 25 ° C., a rotation speed of 6 rpm, and a rotor No. The viscosity was measured under the condition of 3. The results are shown in Table 4.

Figure 0006897227
Figure 0006897227

[紙料の調成]
晒クラフトパルプ(LBKP)をナイアガラ式ビーターにて叩解し、カナディアン・スタンダード・フリーネス(C.S.F)が350mlになるよう調成したスラリーを得た。次いで、当該スラリーに芒硝を添加して、その電気伝導度を0.5mS/cmに調節することにより、1%スラリーの紙料1を調製した。なお、当該電気伝導度は、市販の測定器(商品名「pH/COND METER D−54」、(株)堀場製作所製)を用いて測定した。
[Adjustment of paper charges]
The bleached kraft pulp (LBKP) was beaten with a Niagara beater to obtain a slurry prepared so that the Canadian Standard Freeness (CSF) was 350 ml. Next, Glauber's salt was added to the slurry to adjust its electrical conductivity to 0.5 mS / cm to prepare a 1% slurry paper material 1. The electrical conductivity was measured using a commercially available measuring instrument (trade name "pH / COND METER D-54", manufactured by HORIBA, Ltd.).

次いで、該紙料1を撹拌しながら硫酸バンド(対パルプ重量1.0%)、カチオン化澱粉(対パルプ重量0.8%)(日本食品化工:ネオタック30T)、実施例1の両性ポリアクリルアミド(対パルプ重量0.3%)の順に添加した後、炭酸カルシウム(対パルプ15%)(奥多摩工業:タマパールTP121)を添加した。得られたパルプスラリーを用いてTAPPI角型シートマシンを用いて成紙坪量が80g/mになるように抄紙した。得られた湿紙を定法通りプレス、乾燥し成紙1を得た。実施例2〜15及び比較例1〜11の両性ポリアクリルアミドについても同様に用いて、成紙1をそれぞれ得た。 Next, while stirring the paper material 1, a sulfuric acid band (based on pulp weight 1.0%), cationized starch (based on pulp weight 0.8%) (Nippon Shokuhin Kako: Neotac 30T), and amphoteric polyacrylamide of Example 1. After adding in the order of (weight to pulp 0.3%), calcium carbonate (15% to pulp) (Okutama Kogyo: Tamapearl TP121) was added. Using the obtained pulp slurry, paper was made using a TAPPI square sheet machine so that the basis weight of the paper was 80 g / m 2 . The obtained wet paper was pressed according to a conventional method and dried to obtain adult paper 1. The amphoteric polyacrylamides of Examples 2 to 15 and Comparative Examples 1 to 11 were also used in the same manner to obtain adult paper 1, respectively.

前記紙料1を撹拌しながら硫酸バンド(対パルプ重量1.0%)、カチオン化澱粉(対パルプ重量0.8%)(日本食品化工:ネオタック30T)、実施例1の両性ポリアクリルアミド(対パルプ重量0.3%)の順に添加した後、炭酸カルシウム(対パルプ30%)(奥多摩工業:タマパールTP121)を添加した。得られたパルプスラリーを用いてTAPPI角型シートマシンを用いて成紙坪量が80g/mになるように抄紙した。得られた湿紙を定法通りプレス、乾燥し成紙2を得た。実施例2〜15及び比較例1〜11の両性ポリアクリルアミドについても同様に用いて、成紙2をそれぞれ得た。 Sulfate band (against pulp weight 1.0%), cationized starch (against pulp weight 0.8%) (Nippon Shokuhin Kako: Neotac 30T), and amphoteric polyacrylamide of Example 1 (paired) while stirring the paper material 1. After adding in the order of pulp weight 0.3%), calcium carbonate (30% of pulp) (Okutama Kogyo: Tamapearl TP121) was added. Using the obtained pulp slurry, paper was made using a TAPPI square sheet machine so that the basis weight of the paper was 80 g / m 2 . The obtained wet paper was pressed according to a conventional method and dried to obtain adult paper 2. The amphoteric polyacrylamides of Examples 2 to 15 and Comparative Examples 1 to 11 were also used in the same manner to obtain adult paper 2.

両性ポリアクリルアミドを加えないこと以外はすべて成紙2と同じ方法で成紙3を得た。 A paper 3 was obtained in the same manner as the paper 2 except that amphoteric polyacrylamide was not added.

[比引張強さの測定]
前記成紙1及び成紙2の比引張強さをJIS P 8113に準拠して測定した。比引張強さ等の紙力は添加された両性ポリアクリルアミドの種類だけでなく、紙中の灰分量に大きく影響を受ける。両性ポリアクリルアミドの種類により填料の凝集性、相互作用が異なり紙中への填料の歩留りが変化するため、各種両性ポリアクリルアミドを添加した紙の灰分量は通常同量にはならない。前述の通り、紙力は紙中灰分量に影響を受けるため、両性ポリアクリルアミドの添加による紙力向上効果の差は同等の紙中灰分量に補正したもので比較する必要がある。比引張強さは以下に従って補正した。
同じ両性ポリアクリルアミドを添加して調製した成紙1及び成紙2の紙中灰分率及び比引張強さの関係(図4)から次式により紙中灰分20%の強度を概算した。結果を表5に示す。
[Measurement of specific tensile strength]
The specific tensile strengths of the finished paper 1 and the finished paper 2 were measured according to JIS P 8113. Paper strength such as specific tensile strength is greatly affected not only by the type of amphoteric polyacrylamide added, but also by the amount of ash in the paper. Since the cohesiveness and interaction of the filler differ depending on the type of amphoteric polyacrylamide and the yield of the filler in the paper changes, the ash content of the paper to which various amphoteric polyacrylamide is added is usually not the same amount. As described above, since the paper strength is affected by the amount of ash in the paper, it is necessary to compare the difference in the effect of improving the paper strength by adding the amphoteric polyacrylamide with the one corrected to the same amount of ash in the paper. The specific tensile strength was corrected as follows.
From the relationship between the ash content in the paper and the specific tensile strength of the paper 1 and the paper 2 prepared by adding the same amphoteric polyacrylamide (FIG. 4), the strength of the paper ash content of 20% was estimated by the following formula. The results are shown in Table 5.

Y(20%)=Y−a(X−20)
a=(Y− Y)/ (X− X
Y (20%) = Y 2 -a (X 2 -20)
a = (Y 2 -Y 1 ) / (X 2 -X 1 )

Y(20%):紙中灰分20%換算の比引張強さ
:成紙1の紙中灰分率
:成紙2の紙中灰分率
:成紙1の比引張強さ
:成紙2の比引張強さ
Y (20%): Specific tensile strength in terms of 20% ash content in paper X 1 : Specific tensile strength in paper of adult paper 1 X 2 : Specific tensile strength in paper of adult paper 2 Y 1 : Specific tensile strength in paper 1 Y 2 : Specific tensile strength of adult paper 2

[内部強度の測定]
前記成紙1及び成紙2の内部強度をJ.TAPPI No.18−2に準拠して測定した。比引張強さと同様に紙中灰分20%での内部強度を算出した結果を表5に示す。
[Measurement of internal strength]
J. TAPPI No. Measured according to 18-2. Table 5 shows the results of calculating the internal strength at 20% ash content in paper in the same manner as the specific tensile strength.

[地合変動係数の測定]
前記成紙2からの通過光(輝度)を市販の測定器(商品名「パーソナル画像処理システムHyper−700」、OBS社製)に取り込み、輝度分布を統計解析することにより得られた値を、該成紙2の地合変動係数(変動係数)とした。地合変動係数は、その値が小さい程、地合が良好であることを意味する。結果を表5に示す。
[Measurement of coefficient of variation]
The value obtained by incorporating the passing light (brightness) from the paper 2 into a commercially available measuring instrument (trade name "Personal image processing system Hyper-700", manufactured by OBS) and statistically analyzing the brightness distribution is obtained. The coefficient of variation (coefficient of variation) of the paper 2 was used. The smaller the coefficient of variation of the formation, the better the formation. The results are shown in Table 5.

[両性ポリアクリルアミドの定着率]
前記成紙2と成紙3それぞれの窒素分を、市販の測定装置(製品名「TN−110」、三菱化学(株)製)を用いて求め、該窒素分の値を以下に示す計算式に代入し、両性ポリアクリルアミドの定着率を算出した。結果を表5に示す。
[Fixation rate of amphoteric polyacrylamide]
The nitrogen content of each of the paper 2 and the paper 3 is determined using a commercially available measuring device (product name "TN-110", manufactured by Mitsubishi Chemical Corporation), and the value of the nitrogen content is calculated by the following formula. The fixation rate of amphoteric polyacrylamide was calculated by substituting into. The results are shown in Table 5.

定着率(%)=〔(成紙2の窒素分−成紙3の窒素分)÷(実施例1に係る両性ポリアクリルアミドの理論窒素分×該両性ポリアクリルアミドの添加率)〕×100 Fixing rate (%) = [(Nitrogen content of adult paper 2 − Nitrogen content of adult paper 3) ÷ (Theoretical nitrogen content of amphoteric polyacrylamide according to Example 1 × Addition rate of the amphoteric polyacrylamide)] × 100

Figure 0006897227
Figure 0006897227

Claims (17)

下記要件〔1〕、〔2〕、〔3〕、〔4〕及び〔5〕を備える両性ポリアクリルアミドを含有する、無機填料を対パルプの重量(固形分)で10〜50重量%含有するパルプスラリー用紙力増強剤。
〔1〕その構成成分(1)がアクリルアミド(a)、αメチル基含有カチオン性ビニルモノマー(b)、アニオン性ビニルモノマー(c)を含み、
(c)成分がαメチル基不含有不飽和カルボン酸であり、αメチル基不含有不飽和カルボン酸がアクリル酸及び/又はその塩を含む
〔2〕その構成成分(1)における(b)成分の比率が1〜15モル%であり、かつ、(c)成分の比率が1〜10モル%である
〔3〕そのH−NMRスペクトルの0.9ppm〜1.35ppmの範囲に該(b)成分のαメチル基に帰属する高磁場側吸収帯Aと低磁場側吸収帯Bがあり、かつ、該吸収帯Aの面積(As)及び該吸収帯Bの面積(Bs)の合計面積に対する該吸収帯Aの面積(As)の比率[As/(As+Bs)]が12%以上25%未満である
〔4〕その15重量%水溶液(25℃)の粘度が3,000〜30,000mPa・sである
〔5〕その重量平均分子量(Mw)と数平均分子量(Mn)の比率(Mw/Mn)が3.5以下である
A pulp containing 10 to 50% by weight of an inorganic filler based on the weight (solid content) of the pulp , which contains an amphoteric polyacrylamide satisfying the following requirements [1], [2], [3], [4] and [5]. Slurry paper strength enhancer.
[1] As a component (1) is acrylamide (a), alpha-methyl group-containing cationic vinyl monomer (b), seen containing an anionic vinyl monomer (c),
The component (c) is an α-methyl group-free unsaturated carboxylic acid, and the α-methyl group-free unsaturated carboxylic acid contains an acrylic acid and / or a salt thereof [2] The component (b) in the component (1). The ratio of (c) is 1 to 10 mol%, and the ratio of the component (c) is 1 to 10 mol%. [3] Part 1 The (b) is in the range of 0.9 ppm to 1.35 ppm of the H-NMR spectrum. ) There are a high magnetic field side absorption band A and a low magnetic field side absorption band B belonging to the α-methyl group of the component, and the total area of the absorption band A (As) and the absorption band B (Bs). The ratio [As / (As + Bs)] of the area (As) of the absorption band A is 12% or more and less than 25% [4] The viscosity of the 15% by weight aqueous solution (25 ° C.) is 3,000 to 30,000 mPa. [5] The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3.5 or less.
構成成分(1)における(a)成分の比率が55〜97.8モル%である、請求項1の紙力増強剤。 The paper strength enhancer according to claim 1, wherein the ratio of the component (a) to the component (1) is 55 to 97.8 mol%. (b)成分が、第3級アミノ基含有メタクリレート、第3級アミノ基含有メタクリルアミド、第4級塩構造含有メタクリレート、及び第4級塩構造含有メタクリルアミドからなる群より選ばれる少なくとも一種である、請求項1又は2の紙力増強剤。 The component (b) is at least one selected from the group consisting of a tertiary amino group-containing methacrylate, a tertiary amino group-containing methacrylamide, a quaternary salt structure-containing methacrylate, and a quaternary salt structure-containing methacrylamide. , The paper strength enhancer according to claim 1 or 2. 構成成分(1)が、更にαメチル基不含有カチオン性ビニルモノマー(b’)を含む、請求項1〜3のいずれかの紙力増強剤。 The paper strength enhancer according to any one of claims 1 to 3, wherein the component (1) further contains an α-methyl group-free cationic vinyl monomer (b'). (b’)成分が、第3級アミノ基含有アクリレート、第3級アミノ基含有アクリルアミド、第4級塩構造含有アクリレート、及び第4級塩構造含有アクリルアミドからなる群より選ばれる少なくとも一種である、請求項4の紙力増強剤。 The component (b') is at least one selected from the group consisting of a tertiary amino group-containing acrylate, a tertiary amino group-containing acrylamide, a quaternary salt structure-containing acrylate, and a quaternary salt structure-containing acrylamide. The paper strength enhancer according to claim 4. 構成成分(1)における(b’)成分の比率が0.1〜3モル%である、請求項4又は5の紙力増強剤。 The paper strength enhancer according to claim 4 or 5, wherein the ratio of the component (b') to the component (1) is 0.1 to 3 mol%. αメチル基不含有不飽和カルボン酸がアクリル酸及び/又はその塩を含み、かつその占有比率が50モル%以上である、請求項の紙力増強剤。 The paper strength enhancer according to claim 1 , wherein the α-methyl group-free unsaturated carboxylic acid contains acrylic acid and / or a salt thereof , and the occupancy ratio thereof is 50 mol% or more. 構成成分(1)が更に架橋性モノマー(d)を含む、請求項1〜のいずれかの紙力増強剤。 The paper strength enhancer according to any one of claims 1 to 7 , wherein the component (1) further contains a crosslinkable monomer (d). (d)成分が、N,N−ジメチルアクリルアミド及びメチレンビスアクリルアミドからなる群より選ばれる少なくとも一種を含む、請求項の紙力増強剤。 (D) The paper strength enhancer according to claim 8 , wherein the component comprises at least one selected from the group consisting of N, N-dimethylacrylamide and methylenebisacrylamide. 構成成分(1)における(d)成分の比率が0.01〜1モル%である、請求項又はの紙力増強剤。 The paper strength enhancer according to claim 8 or 9 , wherein the ratio of the component (d) to the component (1) is 0.01 to 1 mol%. 構成成分(1)が更に連鎖移動性ビニルモノマー(e)を含む、請求項1〜1のいずれかの紙力増強剤。 The paper strength enhancer according to any one of claims 1 to 10 , wherein the component (1) further contains a chain transfer vinyl monomer (e). (e)成分が(メタ)アリルスルホン酸塩を含む、請求項1の紙力増強剤。 Component (e) comprises (meth) allyl sulfonate, paper strength agent according to claim 1 1. 構成成分(1)における(e)成分の比率が0.05〜2モル%である、請求項1又は1の紙力増強剤。 Ratio of component (e) in component (1) is 0.05 to 2 mol%, claim 1 1 or 1 2 of a paper strength agent. 請求項1〜1のいずれかの紙力増強剤を、無機填料を対パルプ濃度で10〜50重量%含有する抄紙系内に添加することを特徴とする、の製造方法。 One of paper strength agent according to claim 1 to 1 3, characterized by adding an inorganic filler at a pulp concentration in the papermaking system containing 10 to 50 wt%, process for manufacturing paper. 無機填料が、タルク、カオリン及び炭酸カルシウムからなる群より選ばれる少なくとも一種である、請求項1の製造方法。 Mineral filler is talc, at least one is a method for producing a paper according to claim 1 4 selected from the group consisting of kaolin and calcium carbonate. 請求項1又は1の製造方法で得られる Paper obtained in claim 1 4 or 1 5 paper making method. 紙中灰分が10重量%以上である、請求項1

In paper ash content is 10 wt% or more, the paper of claim 1 6.

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