JP4354370B2 - Method for producing bleached pulp - Google Patents

Description

  The present invention relates to a method for producing bleached pulp when producing paper.

  Since the cellulose pulp obtained by mechanical or chemical treatment is somewhat colored, it is bleached to increase the whiteness. Known bleaching agents used for bleaching pulp are chlorine bleaching agents such as chlorine and hypochlorous acid, and oxygen bleaching agents such as oxygen and hydrogen peroxide. The whiteness of the bleached pulp is important because it greatly affects the whiteness of the pulp sheet and paper.

Patent Document 1 discloses a pulp bleaching improver made of a specific compound of the alkanoyloxybenzene type. Patent Document 2 discloses a pulp bleaching method using a compound that reacts with a peroxide to release active oxygen. Patent Document 3 discloses a method for bleaching cellulose pulp that is treated with oxygen gas and / or peroxide in the presence of an acylated product of an amine, and that a surfactant or an organic solvent can be used in combination. Is described. Patent Document 4 discloses a bleaching process in which an agglomerate containing a bleach activator, a wetting agent, etc. is added to a dilute hydrogen peroxide solution, and the bleach activator is reacted with hydrogen peroxide to bleach the pulp. Yes.
JP-A-1-104893 JP-A-4-108192 Japanese Patent Laid-Open No. 5-18689 JP 2002-525453 A

  However, in recent years, demands for improving the whiteness of pulp sheets and paper are further increasing, and in particular, there is a demand for a technology that can further increase the whiteness by increasing the amount of used paper pulp accompanying the promotion of reuse of used paper. In addition to diversification of paper raw materials and applications, it is also desired to obtain a bulky and high strength pulp sheet in addition to high whiteness. In particular, when waste paper pulp is used as a raw material, whiteness tends to decrease, and bulk and strength tend to decrease, so these improvements are important. From this point of view, it is difficult to say that the technique of the patent document presented above provides bleached pulp from which a pulp sheet that can sufficiently satisfy all of whiteness, bulkiness, and strength can be obtained.

  An object of the present invention is to provide a method capable of producing a bleached pulp from which a pulp sheet having high whiteness is obtained and a bulky and high-strength pulp sheet can be obtained even when used paper pulp is used as a raw material pulp.

  This invention manufactures bleached pulp which manufactures bleached pulp from raw material pulp using the composition obtained by mixing a bleach activator (A) and a dispersing agent (B), and an oxidizing agent (C). A bleaching activator (A) is an acetylated product of amine (A1) [hereinafter referred to as component (A1)], a dispersant (B) is a solvent (B1-1), and a nonionic surfactant A method for producing bleached pulp (hereinafter referred to as Method 1), which is one or more compounds selected from the group consisting of (B1-2) and a cationic surfactant (B1-3) [hereinafter referred to as (B1) component]. )

  The present invention also relates to a composition obtained by mixing the bleach activator (A) [hereinafter referred to as component (A)] and the dispersant (B) [hereinafter referred to as component (B)], and an oxidizing agent ( C) [hereinafter referred to as component (C)] and a bleaching pulp production method for producing bleached pulp from raw pulp, wherein the bleach activator (A) is alkanoyloxybenzenesulfonic acid or a salt thereof (A2 ) [Hereinafter referred to as (A2) component], and the dispersant (B) is an anionic surfactant (B2) (hereinafter referred to as (B2) component). )

  According to the production method of the present invention, bleached pulp having high whiteness can be obtained, and when used paper pulp is used as raw material pulp, a bleached pulp from which a bulky and high strength pulp sheet can be obtained can be produced.

<Raw material pulp>
The raw material pulp which is the target of the production method of the present invention is a cellulose-containing material, and GP (ground wood pulp), RMP (refiner mechanical pulp), TMP (thermomechanical pulp), CGP (chemiground pulp), SCP (semi-chemical) Pulp), SP (sulfite pulp), KP (craft pulp), AP (alkaline pulp), waste paper pulp, etc., and can be applied to any wood (conifer, broadleaf), non-wood (herbaceous) pulp. . Further, the slurry concentration of the cellulose-containing material can be applied to any of a low concentration (less than 10% by weight), a medium concentration (10 to 20% by weight), and a high concentration (20% by weight or more). Waste paper pulp includes deinked pulp obtained by deinking waste paper pulp. In particular, in the present invention, the raw material pulp preferably contains waste paper pulp.

<(A) component>
(1) (A1) component As the acetylated product of amine (A1), triacetylamine, tripropionylamine, diacetylaniline, diacetyl-p-toluidine, tetraacetylmethylenediamine, tetrapropionylmethylenediamine, tetraacetylethylenediamine, tetrapropionyl And ethylenediamine, pentaacetyldiethylenetriamine, pentapropionyldiethylenetriamine, polyalkylenepolyamine and fatty acid amide, polyalkylenepolyamine and fatty acid amide condensed with urea, and the like. Of these, tetraacetylethylenediamine (TAED) is preferable. In the present invention, in the method 1, these (A1) components are used in combination with the (B1) component.

(2) Component (A2) As the alkanoyloxybenzenesulfonic acid or salt (A2), the following general formula (A2)
RCOO-Ph-SO ₃ M (A2)
[Wherein, R represents a hydrocarbon group having 1 to 30 carbon atoms, preferably an alkyl group or an alkenyl group, Ph represents a phenylene group, and M represents a hydrogen atom or an alkali metal. ]
The compound represented by these is mentioned. Specifically, acetoxybenzenesulfonic acid, p-nonanoyloxybenzenesulfonic acid (NOBS), p-lauroyloxybenzenesulfonic acid (LOBS), benzoyloxybenzenesulfonic acid and the like, and alkali metal salts thereof, preferably A sodium salt is mentioned. In the present invention, in the method 2, these components (A2) are used in combination with the component (B2).

<(B) component>
The component (B) is a dispersant component that can disperse or dissolve the component (A), and includes a solvent (B1-1), a nonionic surfactant (B1-2), and a cationic surfactant (B1-3). One or more compounds selected from the group [component (B1)] or an anionic surfactant [component (B2)]. Nonionic surfactant (B1-2) contains polyalkylene glycol. The cationic surfactant (B1-3) contains a cationic polymer compound.

(1) Component (B1) Examples of the solvent (B1-1) include ethanol, acetone, acetonitrile, dimethylformamide, chloroform and the like, which are organic solvents in which the component (A1) is dissolved.

  Moreover, as a nonionic surfactant (B1-2), the following are mentioned, for example.

(B1-2-1) Polyoxyalkylene alkyl or alkenyl ether, wherein the alkyl group or alkenyl group has an average carbon number of 8 to 24, the alkylene oxide has 2 to 4 carbon atoms, and an alkylene oxide addition mole The number is 1 to 300 moles on average. The addition form of the alkylene oxide may be single, block or random.

(B1-2-2) polyoxyalkylene alkyl phenyl ether, wherein the average carbon number of the alkyl group is 6 to 12, the carbon number of the alkylene oxide is 2 to 4, and the alkylene oxide addition mole number is an average 1 to 300 moles. The addition form of the alkylene oxide may be single, block or random.

(B1-2-3) A higher fatty acid alkanolamide represented by the following general formula or an alkylene oxide adduct thereof.

[Where,
R ¹ : an alkyl group or alkenyl group having 10 to 20 carbon atoms
R ² , R ³ : the same or different, hydrogen atom or CH ₃
m, n represents a number from 0 to 300, and m + n = 1 to 300. ]

(B1-2-4) A sucrose fatty acid ester, wherein the fatty acid part has an average carbon number of 8 to 24.

(B1-2-5) Fatty acid glycerin ester, wherein the fatty acid part has an average carbon number of 8 to 24.

(B1-2-6) Amine oxide. For example, the alkyl or alkenylamine oxide which has a C1-C24 linear or branched alkyl group or alkenyl group is mentioned. More preferred amine oxides include alkylamine oxides represented by the following general formula.

[Where,
R ⁴ : an alkyl group or alkenyl group having 8 to 24 carbon atoms
R ⁵ , R ⁶ : the same or different alkyl group having 1 to 3 carbon atoms
D: -NHCO- group or -CONH-
E: C1-C5 alkylene group
a, b represents a number of 0 or 1, and a = b = 0 or a = b = 1. ]

In the above general formula, R ⁴ is an alkyl group or alkenyl group having 8 to 24 carbon atoms, and an alkyl group having 12 to 18 carbon atoms is particularly preferable. R ⁵ and R ⁶ are each an alkyl group having 1 to 3 carbon atoms, and a methyl group having 1 carbon atom is particularly preferable.

(B1-2-7) A nonionic surfactant obtained by condensing alkylene oxide. Examples of the alkylene oxide include ethylene oxide (hereinafter referred to as EO), propylene oxide (hereinafter referred to as PO), butylene oxide (hereinafter referred to as BO), etc. Absent. The average number of moles of alkylene oxide added is preferably 1 to 300.

(B1-2-8) Alkyl, alkenyl or alkylphenyl polysaccharides. For example, alkyl, alkenyl, or alkylphenyl glycoside represented by the following general formula can be mentioned.
R ⁷ (OR ⁸ ) _x G _y
[Where,
R ⁷ : linear or branched alkyl group or alkenyl group having 8 to 18 carbon atoms, or alkylphenyl group having 14 to 24 carbon atoms in total
R ⁸ : alkylene group having 2 to 4 carbon atoms
G: Residue derived from glucose
x: number of average values 0-20
y: The number of average values 1-10 is shown. ]

(B1-2-9) An alkylene oxide adduct of a polyhydric alcohol. Examples of the polyhydric alcohol include glycerin, pentaerythritol, and sucrose. The alkylene oxide has 2 to 4 carbon atoms, and the addition form of the alkylene oxide may be single, block or random. The average number of moles of alkylene oxide added is preferably 1 to 300.

  Among these nonionic surfactants, polyoxyalkylene alkyl or alkenyl ether is preferable in terms of excellent dispersibility of the component (A).

  Further, as the cationic surfactant (B1-3), alkyl (preferably having 12 to 18 carbon atoms) such as lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, cetyltrimethylammonium chloride, trimethylammonium salt; distearyldimethylammonium Dialkyl (preferably 12-18 carbon atoms) dimethylammonium salt; alkyl (preferably 12-14 carbon atoms) dimethylbenzylammonium chloride, etc. Alkyl (preferably having 12 to 14 carbon atoms) dimethylbenzylammonium salt; substituted benzalkonium salt; monocationic compound such as benzethonium salt, N-alkyl-N, , N ', N', N'- pentamethyl - polycationic compounds such as propylene ammonium salts. In addition, cationic polymer compounds such as poly N, N-dimethylaminoethyl methacrylate may be used. Of these cationic surfactants, alkyltrimethylammonium salts and dialkyldimethylammonium salts are preferred.

(2) Component (B2) Examples of the anionic surfactant (B2) include the following.
(B2-1) An alkyl sulfate ester salt or alkylbenzene sulfate ester salt having a linear or branched alkyl group, wherein the alkyl group has an average carbon number of 8 to 24.

(B2-2) an alkyl or alkenyl ether sulfate salt having a linear or branched alkyl group or alkenyl group, to which an alkylene oxide is added, wherein the average carbon number of the alkyl group or alkenyl group is 8 to 24 Yes, the average number of moles of alkylene oxide added per molecule is 0.5 to 8 moles. The alkylene oxide has 2 to 4 carbon atoms, and the addition form of the alkylene oxide may be single, block or random.

(B2-3) Alkyl or alkenyl phosphate, wherein the alkyl group or alkenyl group has an average carbon number of 8 to 24.

(B2-4) Olefin sulfonate having an average of 8 to 24 carbon atoms.

(B2-5) Alkanesulfonate having an average of 8 to 24 carbon atoms.

(B2-6) Saturated or unsaturated fatty acid salt having an average of 8 to 24 carbon atoms.

(B2-7) An alkyl or alkenyl ether carboxylate to which an alkylene oxide is added, wherein the average carbon number of the alkyl group or alkenyl group is 10 to 20, and the average number of moles of alkylene oxide added per molecule is What is 0.5-8 mol. The alkylene oxide has 2 to 4 carbon atoms, and the addition form of the alkylene oxide may be single, block or random.

(B2-8) α-sulfo fatty acid salt or α-sulfo fatty acid ester represented by the following general formula

[Where,
R ⁹ : an alkyl group or alkenyl group having 8 to 24 carbon atoms
J: C1-C3 alkyl group or cation
Z: represents a cation. ]
Examples of the cation of the anionic surfactant include alkali metal ions such as sodium and potassium.

  Of these anionic surfactants, alkyl sulfates and alkyl ether sulfates are preferred.

<(C) component>
Examples of the oxidizing agent (C) include those that act as oxygen bleaches, such as ozone, oxygen, percarbonate, peracetic acid, hydrogen peroxide, perborate, perphosphate, metal peroxide, and the like. Can be mentioned. Of these, hydrogen peroxide is preferable.

<Method for producing bleached pulp>
In the present invention, bleaching pulp is produced by bleaching raw pulp using a composition obtained by previously mixing the bleach activator (A) and the dispersant (B) and the oxidizing agent (C). However, as described above, the component (A) and the component (B) are the combination of the component (A1) and the component (B1) (method 1) in the method 1, and the component (A2) and the component (B2) in the method 2. The combination is adopted.

  And this invention mixes (A) component and (B) component previously, and uses the composition containing both. The weight ratio of the component (A1) to the component (B1) in the composition is preferably (A1) / (B1) = 99/1 to 1/99, more preferably 90/10 to 10/90. The weight ratio of the component (A1) to the component (B1) in the composition used in Method 2 is (A2) / (B2) = 99/1 to 1/99, more preferably 90/10 to 10/90. Is preferred. Thus, the whiteness and the paper quality are improved by using the component (A) and the component (B) after mixing in advance as a composition containing them. This is because the (A) component and the (B) component are mixed so as to be uniformly dispersed to form a complex, and before the (C) component and the (A) component react, the (A) component Is presumably because the action on the raw material pulp is enhanced.

  The amount of component (C) used in Method 1 and Method 2 may be adjusted according to the target whiteness and the type of raw pulp, but is 0.01 to 10 weights per 100 parts by weight of raw pulp (absolutely dry). Part is one measure.

  In the method 1 and method 2, the weight ratio of the component (A) to the component (C) is preferably (A) / (C) = 1/99 to 99/1, particularly preferably 10/90 to 85/15.

  Both method 1 and method 2 can be carried out in accordance with a known method for producing bleached pulp. Usually, a water-pulp slurry containing raw pulp and water is prepared, and components (A) to (C) are mixed. Bleaching raw pulp in the presence. In this invention, after mixing (A) component and (B) component beforehand and obtaining the composition containing these, what is necessary is just to add to a pulp slurry, The addition order of the said composition and (C) component is ask | required Absent. These additions are preferably carried out at room temperature (25 ° C.) or less where the bleaching reaction hardly occurs. When hydrogen peroxide is used as the component (C), it is preferable to bleach the raw pulp under an alkaline region using an alkali agent such as sodium hydroxide or sodium silicate. The slurry temperature during bleaching is preferably 40 to 100 ° C. The pulp that has been bleached is appropriately cooled and diluted, and then subjected to a papermaking process to produce a pulp sheet. In the present invention, when used paper pulp is used as the raw material pulp, bleached pulp is obtained from which paper having improved bulk and strength in addition to whiteness can be obtained.

  The raw material pulp was bleached as follows using the components (A) to (C) shown in Tables 1 and 2, and the performance of the pulp sheet produced from the obtained bleached pulp was evaluated. The results are shown in Tables 1 and 2.

(1) Disaggregation of raw material waste paper Unprinted newsprint as raw material waste paper was weighed 120 g by dry pulp weight to prepare a pulp slurry having a pulp concentration of 15% by weight. Sodium hydroxide 1.2 wt% (vs. pulp dry weight), sodium silicate 1.2 wt% (vs pulp dry weight), DI-767 (manufactured by Kao Corporation, polyoxyalkylene alkyl ether type non-ion) Surfactant) was added in an amount of 0.2% by weight (vs. pulp dry weight) and disaggregated at 40 ° C. for 7 minutes under stirring at 450 rpm.

(2) Bleach The slurry is collected so that the dry weight is 40 g. Separately, an alkaline aqueous solution of sodium hydroxide 1.2% by weight (vs. pulp dry weight), No. 3 sodium silicate 1.2% by weight (vs. pulp dry weight) was prepared. ) Component and (B) component are added and made uniform, and then added to the pulp slurry. Next, the component (C) in Table 1 or Table 2 is added to the pulp slurry. Bleaching is carried out at 60 ° C. for 0.5 hour or 2 hours, immersed in ice water, and the pulp is cooled to finish bleaching. In the component (A), TAED manufactured by ACROSS ORGANICS was used. LOBS used was synthesized from lauroyl chloride synthesized from lauric acid according to Reference Example 2 (paragraphs 0052 to 0053) of JP-A-8-41492 and disodium p-phenolsulfonic acid.

(3) Papermaking Using a diluted slurry in which the pulp concentration in the pulp slurry after bleaching is diluted with water so as to be 2% by weight and aluminum sulfate (sulfuric acid band) is added by 10% by weight (vs. pulp dry weight). The paper was made with a tappi paper machine and then dried with a drum dryer at 105 ° C. for 2 minutes to prepare a pulp sheet having a basis weight of 150 g / m ² .

(4) Evaluation The whiteness, tightness, and burst strength of the pulp sheet were measured by the following methods.

(4-1) Whiteness
According to JIS P 8123 Hunter Whiteness. A difference of 0.5 points in whiteness is fully recognized as a significant difference.

(4-2) Tension The basis weight (g / m ² ) and thickness (mm) of the conditioned sheet were measured, and the tension (g / cm ³ ) was determined by the following formula.
Tension = (basis weight) / (thickness) × 0.001
The smaller the tension is, the higher the bulk is, and a difference of 0.005 in the tension is well recognized as a significant difference.

(4-3) Burst strength Burst strength was measured by JIS P8112 method as a paper strength measurement item. The 0.05 point difference in burst strength is well recognized as a significant difference.

In addition, (B) component in a table | surface is the following. In addition, EOp is EO average addition mole number, POp is PO average addition mole number.
・ Alcohol EO: EO adduct of stearyl alcohol (EOp50)
・ Alcohol EOPO: lauryl alcohol EO, PO block adduct (EOp20, POp10)
・ Glycerin EO / PO: EO of glycerin, PO random adduct (EOp150, POp100)
-Polyethylene glycol: EO condensate (EOp50)
Coatamine 86P: manufactured by Kao Corporation, stearyltrimethylammonium chloride MD polymer: manufactured by Kao Corporation, poly N, N-dimethylaminoethyl diethyl sulfate sulfate Emar 10: manufactured by Kao Corporation, sodium lauryl sulfate・ Poise 530: manufactured by Kao Corporation, polycarboxylate type polymer surfactant ・ Demol MS: manufactured by Kao Corporation, sodium salt of aromatic sulfonic acid formaldehyde condensate ・ Amphithol 24B: manufactured by Kao Corporation, Lauryldimethylaminoacetic acid betaine polymer A: copolymer of dimethylaminoethyl methacrylic acid / sodium acrylate (molar ratio 6/1)

Claims (9)

A method for producing bleached pulp in which bleached pulp is produced from raw pulp using a composition obtained by mixing a bleach activator (A) and a dispersant (B) and an oxidizing agent (C). The bleaching activator (A) is an amine acetylated product (A1), and the dispersant (B) is composed of a nonionic surfactant (B1-2) and a cationic surfactant (B1-3). A method for producing bleached pulp, which is one or more selected compounds. The method for producing bleached pulp according to claim 1, wherein the nonionic surfactant (B1-2) is a nonionic surfactant selected from the following (B1-2-1) to (B1-2-9).
(B1-2-1) Polyoxyalkylene alkyl or alkenyl ether, wherein the alkyl group or alkenyl group has an average carbon number of 8 to 24, the alkylene oxide has 2 to 4 carbon atoms, and an alkylene oxide addition mole The number is 1 to 300 moles on average.
(B1-2-2) polyoxyalkylene alkyl phenyl ether, wherein the average carbon number of the alkyl group is 6 to 12, the carbon number of the alkylene oxide is 2 to 4, and the alkylene oxide addition mole number is an average 1 to 300 moles.
(B1-2-3) A higher fatty acid alkanolamide represented by the following general formula or an alkylene oxide adduct thereof.

[Where,
R ¹ : an alkyl group or alkenyl group having 10 to 20 carbon atoms
R ² , R ³ : the same or different, hydrogen atom or CH ₃
m, n represents a number from 0 to 300, and m + n = 1 to 300. ]
(B1-2-4) A sucrose fatty acid ester, wherein the fatty acid part has an average carbon number of 8 to 24.
(B1-2-5) Fatty acid glycerin ester, wherein the fatty acid part has an average carbon number of 8 to 24.
(B1-2-6) Amine oxide.
(B1-2-7) A nonionic surfactant obtained by condensing alkylene oxide.
(B1-2-8) Alkyl, alkenyl or alkylphenyl polysaccharides.
(B1-2-9) An alkylene oxide adduct of a polyhydric alcohol. Cationic surfactant (B1-3) is an alkyl (carbon number 12-18) trimethylammonium salt, dialkyl (carbon number 12-18) dimethylammonium salt, alkyl (carbon number 12-14) dimethylbenzylammonium salt, substituted Cationic surface activity selected from benzalkonium salt, benzethonium salt, N-alkyl-N, N, N ′, N ′, N′-pentamethyl-propyleneammonium salt, and poly N, N-dimethylaminoethyl methacrylate The manufacturing method of the bleached pulp of Claim 1 or 2 which is an agent. The weight ratio of the bleaching activator (A) to the dispersant (B) in the composition is (A) / (B) = 99/1 to 1/99. The manufacturing method of the bleached pulp of description. The bleach according to any one of claims 1 to 4, wherein the bleach activator (A) and the oxidizer (C) are used in a weight ratio of (A) / (C) = 10/90 to 85/15. Pulp manufacturing method. Using a water-pulp slurry containing raw pulp and water, bleaching the raw pulp in the presence of (A) to (C), and adding (A) to (C) to the water-pulp slurry The method for producing bleached pulp according to any one of claims 1 to 5, which is carried out at 25 ° C or lower. The manufacturing method of the bleached pulp of Claim 6 which bleaches a raw material pulp by making the temperature of the said water-pulp slurry into 40-100 degreeC. The method for producing bleached pulp according to any one of claims 1 to 7 , wherein the raw material pulp contains waste paper pulp. The manufacturing method of a pulp sheet which has the process of manufacturing a bleached pulp with the manufacturing method of any one of Claims 1-8, and the process of papermaking the bleached pulp obtained by this process.