JP2007126776A - Method for treatment of waste paper pulp and deinking assistant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for the treatment of waste paper pulp and a deinking assistant to perform the deinking and bleaching treatment of waste paper pulp in high efficiency. <P>SOLUTION: The method for the treatment of waste paper pulp comprises the contact of waste paper pulp with hydrogen peroxide and a metal complex catalyst including an M-bis(salicylidene)ethylenediamine complex (M-salen complex) expressed by general formula (1) to remove residual ink from the pulp and bleach pulp fiber. The deinking assistant for the removal of residual ink from waste paper pulp is expressed by general formula (1). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a waste paper pulp removal method and a waste paper pulp processing method for bleaching the pulp fibers and a deinking aid, and more particularly, a waste paper in which a metal complex catalyst and hydrogen peroxide are brought into contact with the waste paper pulp. The present invention relates to a pulp processing method and a deinking aid.

  In the used paper recycling process, sodium hydroxide, silicate compounds, deinking agents (nonionic surfactants, etc.), hydrogen peroxide, etc. are used. A method using ethylene polyoxypropylene ether has been reported (Patent Document 1). By stirring and reacting these chemicals and waste paper pulp in a disintegrator (pulper), ink (particles) remaining on the waste paper pulp is removed (deinking) and pulp fibers are bleached. Here, the higher the degree of deinking and bleaching required for the recycled pulp, the greater the amount of hydrogen peroxide required, which increases the loss of hydrogen peroxide, thus reducing the loss of hydrogen peroxide and increasing the efficiency of the reaction. There is a need for a method that can be enhanced.

As a conventional method for efficiently deinking and bleaching waste paper pulp, a method using a quaternary ammonium organic acid salt as a bleaching assistant (Patent Document 2), reductive bleaching such as thiourea dioxide, etc. A method for use in combination (Patent Document 3, Patent Document 4 and Patent Document 5) and a method for adding an enzyme such as cellulase (Patent Document 6) have been reported.
However, each of these known methods has various problems such as its profitability and the influence on the corrosion of the apparatus, and does not necessarily reach a satisfactory level.

Japanese Patent No. 2597934 Japanese Patent Laid-Open No. 2002-161491 JP 11-315487 A Japanese Patent Laid-Open No. 10-259584 JP-A-7-279074 Japanese Patent Laid-Open No. 9-241985

  An object of the present invention is to provide a waste paper pulp processing method and a deinking aid capable of efficiently deinking and bleaching waste paper pulp.

  As a result of intensive studies to solve the above problems, the present inventors have determined that when a specific metal complex catalyst and hydrogen peroxide are brought into contact with waste paper pulp, the metal complex catalyst has a hydrogen peroxide bleaching property. Since the deinking property can be improved without hindering, as a result, the new fact that deinking and bleaching of waste paper pulp can be efficiently performed has been found, and the present invention has been completed.

（式中、Ｒ₁、Ｒ₂、Ｒ₃およびＲ₄は、それぞれ同一または異なる基であって、水素原子、低級アルキル基、アリール基、アラルキル基、低級アルコキシ基、アルキルオキシカルボニル基、アリールオキシカルボニル基、ハロゲン原子、トリメチルシリル基、アリーロキシ基、アシロキシ基、アシル基、ニトロ基、ヒドロキシル基、カルボキシル基、カルボキシラト基（カルボン酸塩）、カルバモイル基、ホルミル基またはシアノ基を示す。Ｒ₅は、水素原子、低級アルキル基、アリール基またはアラルキル基を示す。Ｒ₆およびＲ₇は、それぞれ同一または異なる基であって、水素原子、低級アルキル基またはアリール基を示し、さらにＲ₆およびＲ₇は互いに結合して飽和、不飽和の炭化水素環を形成してもよい。Ｍは、酸化数が＋IIIである遷移金属であり、Ｘは１価アニオンである。） That is, the method for treating waste paper pulp of the present invention is a method of removing residual ink from the pulp and bleaching the pulp fiber by bringing the metal complex catalyst and hydrogen peroxide into contact with the waste paper pulp, the metal complex catalyst Is an M- (bissalicylidene) ethylenediamine complex (M-salen complex) represented by the following general formula (1).

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ are the same or different groups, and each is a hydrogen atom, lower alkyl group, aryl group, aralkyl group, lower alkoxy group, alkyloxycarbonyl group, aryloxy group. R ₅ represents a carbonyl group, a halogen atom, a trimethylsilyl group, an aryloxy group, an acyloxy group, an acyl group, a nitro group, a hydroxyl group, a carboxyl group, a carboxylate group (carboxylate), a carbamoyl group, a formyl group, or a cyano group. , A hydrogen atom, a lower alkyl group, an aryl group or an aralkyl group, R ₆ and R ₇ are the same or different groups, each representing a hydrogen atom, a lower alkyl group or an aryl group, and further R ₆ and R _7. May combine with each other to form a saturated or unsaturated hydrocarbon ring, and M has an oxidation number of + III. A transition metal, X is a monovalent anion.)

In the present invention, in the general formula (1), M preferably represents Mn (III), Fe (III), Ru (III), Co (III) or Mo (III). Furthermore, in order to further improve the deinking property of hydrogen peroxide, in the general formula (1), R _{1 to} R ₅ represent hydrogen atoms, and R ₆ and R ₇ represent hydrogen atoms, lower alkyl groups, It is preferable that the saturated hydrocarbon ring is a benzene ring, M represents Mn (III), and the monovalent anion in X represents a carboxylate ion. In particular, in order to improve bleachability in addition to the improvement of the deinking property, in the general formula (1), R _{1 to} R ₅ represent hydrogen atoms, and R ₆ and R ₇ represent lower alkyl groups. , M represents Mn (III), and the monovalent anion in X preferably represents a carboxylate ion.

（式中、Ｒ₁〜Ｒ₅、ＭおよびＸは、前記で定義した通りである。） Another metal complex catalyst according to the present invention is an M- (bissalicylidene) ethylenediamine complex (M-salen complex) represented by the following general formula (2).

(Wherein R _{1 to} R ₅ , M and X are as defined above.)

Further, for more efficient deinking and bleaching of used paper pulp, it is preferable to contact the metal complex catalyst and hydrogen peroxide with the used paper pulp in a solvent. Further, sodium hydroxide, a nonionic interface is used as the solvent. An activator or a silicate compound may be added, and the metal complex catalyst and hydrogen peroxide may be contacted with the waste paper pulp in the solvent.
The deinking aid of the present invention is represented by the above general formula (1) or general formula (2), and is used for removing residual ink from waste paper pulp.

  According to the present invention, since the metal complex catalyst represented by the general formula (1) or the general formula (2) and hydrogen peroxide are brought into contact with waste paper pulp, the metal complex catalyst inhibits the bleaching property of hydrogen peroxide. Therefore, there is an effect that the deinking property is improved, and as a result, the used paper pulp can be efficiently deinked and bleached. In addition, when the metal complex catalyst has a predetermined structure, in addition to improving the deinking property, the bleaching property of waste paper pulp is also improved.

  The method for treating waste paper pulp of the present invention is a method of removing residual ink from the pulp (deinking) and bleaching the pulp fiber by bringing the metal complex catalyst and hydrogen peroxide into contact with the waste paper pulp. The catalyst is M- (bissalicylidene) ethylenediamine complex (M-salen complex) represented by general formula (1) or general formula (2). The metal complex catalyst can improve the deinking property without inhibiting the bleaching property of hydrogen peroxide. This is presumably because the metal complex catalyst activates hydrogen peroxide and increases its oxidation reactivity.

As described above, in the general formula (1) or the general formula (2), R ₁ , R ₂ , R ₃ and R ₄ are the same or different groups, and each represents a hydrogen atom, a lower alkyl group, an aryl group, Aralkyl group, lower alkoxy group, alkyloxycarbonyl group, aryloxycarbonyl group, halogen atom, trimethylsilyl group, aryloxy group, acyloxy group, acyl group, nitro group, hydroxyl group, carboxyl group, carboxylate group (carboxylate), A carbamoyl group, a formyl group or a cyano group;

  Examples of the lower alkyl group include linear or branched lower groups having 1 to 6 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, and t-butyl group. Examples of the aryl group include an aryl group having 6 to 16 carbon atoms such as a phenyl group and a naphthyl group. Examples of the aralkyl group include a benzyl group and a 2-phenylethyl group. As the lower alkoxy group, for example, a straight chain or branched chain having 1 to 6 carbon atoms such as methoxy group, ethoxy group, n-propyloxy group, isopropyloxy group, n-butoxy group, s-butoxy group, t-butoxy group, etc. Examples of the alkyloxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, and an n-propyloxycarbonyl group. Examples include a sulfonyl group, an isopropyloxycarbonyl group, and a benzyloxycarbonyl group. Examples of the aryloxycarbonyl group include a phenoxycarbonyl group and a naphthyloxycarbonyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, and bromine. Examples of the aryloxy group include a phenoxy group. Examples of the acyloxy group include an acetoxy group. Examples of the acyl group include an acetyl group and a benzoyl group. Examples of the carboxylate group (carboxylate) include a sodium carboxylate group, and examples of the carbamoyl group (amide) include an N-methylcarbamoyl group and an N, N-dimethylcarbamoyl group.

In general formula (1) or general formula (2), R ₅ represents a hydrogen atom, a lower alkyl group, an aryl group or an aralkyl group. Examples of the lower alkyl group include a methyl group, an ethyl group, an isopropyl group, Examples thereof include linear or branched lower alkyl groups having 1 to 6 carbon atoms such as a t-butyl group, and examples of the aryl group include aryl groups having 6 to 16 carbon atoms such as a phenyl group and a naphthyl group. Examples of the group include benzyl group and 2-phenylethyl group.

In the general formula (1), R ₆ and R ₇ are the same or different groups, each representing a hydrogen atom, a lower alkyl group or an aryl group, and the lower alkyl group and the aryl group include the R ₁ to The same substituents as those exemplified for R ₅ can be mentioned. R ₆ and R ₇ may combine with each other to form a saturated or unsaturated hydrocarbon ring. Examples of the saturated hydrocarbon ring include cycloalkyl rings such as cyclopentane and cyclohexane. Examples of the saturated hydrocarbon ring include a benzene ring. Specifically, for example, a metal complex catalyst represented by the general formula (2) can be given as an example of the case where R ₆ and R ₇ are bonded to each other to form a benzene ring.

  In the general formula (1), M is a transition metal having an oxidation number of + III, and X is a monovalent anion. The transition metal whose oxidation number is + III is not particularly limited, but in the present invention, Mn (III) [manganese (III)], Fe (III) [iron (III)], Ru (III) [Ruthenium (III)], Co (III) [Cobalt (III)] or Mo (III) [Molybdenum (III)] is preferred. Examples of the monovalent anion include halide ions, hydroxide ions, carboxylate ions, nitrate ions, tetrafluoroborate ions, perchlorate ions, and the like. Examples of the halide ion of the monovalent anion include fluoride ion, chloride ion, bromide ion, and iodide ion. Examples of the carboxylate ion include formate ion, acetate ion, and propionate ion. It is done.

In the present invention, in the general formula (1), R _{1 to} R ₅ represent a hydrogen atom, R ₆ and R ₇ represent a hydrogen atom, a lower alkyl group, or the unsaturated hydrocarbon ring is a benzene ring; Represents Mn (III), the monovalent anion in X preferably represents a carboxylate ion, and more preferably the carboxylate ion is an acetate ion. Thereby, the deinking property of hydrogen peroxide can be further improved.

In particular, in the general formula (1), R _{1 to} R ₅ represent a hydrogen atom, R ₆ and R ₇ represent a lower alkyl group, M represents Mn (III), and the monovalent anion in X is a carboxylic acid It is preferable to represent an ion, more preferably, the lower alkyl group of R ₆ and R ₇ represents a methyl group, and the carboxylate ion is an acetate ion. Thereby, in addition to the improvement of the deinking property, the bleaching property can also be improved.

For the same reason as in the general formula (1), in the general formula (2), R _{1 to} R ₅ represent hydrogen atoms, M represents Mn (III), and the monovalent anion in X is It is preferable to show a carboxylate ion, and it is more preferable that the carboxylate ion is an acetate ion.

The metal complex catalyst represented by the general formula (1) or (2) can be synthesized by a method described in, for example, International Publication No. 97/07191, International Publication No. 97/07192, or the like. . Specifically, in the synthesis of the metal complex catalyst represented by the general formula (1), first, salicylaldehyde or 2-hydroxyphenyl ketone having a substituent represented by R _{1 to} R ₅ and R _{6 are used.} And a diamine compound having a substituent represented by R ₇ is reacted in an alcohol such as methanol to synthesize a salen ligand.

  Next, this salen ligand is mixed with Mn (II), Fe (II), Ru (II), Co (II), Mo (II) salts such as manganese acetate (II) in an alcohol such as methanol. The M- (bissalicylidene) ethylenediamine complex (M-salen complex) represented by the general formula (1) can be obtained by heating and refluxing in an air or oxygen atmosphere.

  The metal complex catalyst represented by the general formula (2) synthesizes a phenyl (Ph) -salen ligand using 1,2-phenylenediamine as the diamine compound. Next, the Ph-salen ligand and Mn (II), Fe (II), Ru (II), Co (II), and Mo (II) salt are mixed with alcohol such as methanol in an air or oxygen atmosphere. By heating and refluxing, an M- (bissalicylidene) ethylenediamine complex (M-salen complex) represented by the general formula (2) can be obtained.

  The metal complex catalyst represented by the general formula (1) or (2) is preferably brought into contact with waste paper pulp at a ratio of 0.1 to 1000 ppm, preferably 50 to 100 ppm, based on the total amount of waste paper. Thereby, deinking and bleaching of waste paper pulp can be performed efficiently. On the other hand, when the metal complex catalyst is less than 0.1 ppm, there is a possibility that the deinking property of hydrogen peroxide cannot be improved, and when it is more than 1000 ppm, it is brought into contact with waste paper pulp more than necessary. This is not preferable because the cost increases.

  The hydrogen peroxide is preferably brought into contact with the used paper pulp at a ratio of 0.1 to 5.0% by weight, preferably 0.5 to 2.0% by weight, based on the total amount of the used paper. In the method of the present invention, since the hydrogen peroxide and the metal complex catalyst are brought into contact with waste paper pulp, predetermined deinking and bleaching properties can be obtained with an amount of hydrogen peroxide within this range. On the other hand, if the amount of hydrogen peroxide is less than 0.1% by weight, the predetermined deinking and bleaching properties may not be obtained. If it exceeds 5.0% by weight, the loss of hydrogen peroxide increases. This is not preferable.

  The temperature of the used paper pulp when the metal complex catalyst and hydrogen peroxide come into contact with the used paper pulp is preferably 20 to 90 ° C, preferably 40 to 70 ° C. The time during which the metal complex catalyst and hydrogen peroxide are in contact with the waste paper pulp is 5 minutes to 120 minutes, preferably 10 minutes to 30 minutes. When the metal complex catalyst and hydrogen peroxide are brought into contact with the used paper pulp within this temperature or time range, the used paper pulp can be reliably deinked and bleached.

  In the method for treating waste paper pulp of the present invention, it is preferable to contact the waste paper pulp with a metal complex catalyst and hydrogen peroxide in a solvent. Thereby, since the metal complex catalyst and hydrogen peroxide easily come into contact with the waste paper pulp, the deinking and bleaching of the waste paper pulp can be performed more efficiently. The solvent is not particularly limited as long as the effects of the method of the present invention are not impaired, and examples thereof include water.

  Specifically, first, waste paper such as newspaper waste paper or newspaper folded leaflet waste paper is added to the solvent and disaggregated with a disintegrator or the like, and the waste paper pulp is dispersed in the solvent. At this time, the waste paper is preferably dispersed in a proportion of 1 to 30% by weight, preferably 10 to 25% by weight, based on the total amount of the solvent and the waste paper. Then, the metal complex catalyst and hydrogen peroxide are added to the solvent, and the metal complex catalyst and hydrogen peroxide are brought into contact with the waste paper pulp.

  In the above description, the case where the used paper pulp is first dispersed in the solvent has been described. However, after adding the metal complex catalyst and hydrogen peroxide to the solvent, the used paper pulp may be dispersed in the solvent. The addition of the metal complex catalyst and hydrogen peroxide is preferably performed in the order of the metal complex catalyst and hydrogen peroxide in order to ensure that the hydrogen peroxide is brought into contact with the waste paper pulp, but the method of the present invention is limited to this. The order may be hydrogen peroxide and a metal complex catalyst. Furthermore, as will be described later, when adding sodium hydroxide, nonionic surfactant, silicate compound, and other compounds to this solvent, first, these compounds are dispersed in the solvent together with waste paper pulp, The metal complex catalyst and hydrogen peroxide are preferably added to the solvent, and hydrogen peroxide is particularly preferably added last. When bringing the metal complex catalyst and hydrogen peroxide into contact with the waste paper pulp, the solvent may be stirred or left standing.

  Here, it is preferable that sodium hydroxide is added to the solvent, and the metal complex catalyst and hydrogen peroxide are brought into contact with the waste paper pulp in the solvent. Thereby, deinking and bleaching of waste paper pulp can be performed more efficiently. The amount of sodium hydroxide added is 0.1 to 1.0% by weight, preferably 0.5 to 0.8% by weight, based on the total amount of used paper.

  Further, it is preferable to add a nonionic surfactant to the solvent, and contact the waste paper pulp with the metal complex catalyst and hydrogen peroxide in the solvent. Since the nonionic surfactant functions as a deinking agent, the deinking property is further improved. The addition amount of the nonionic surfactant is 0.001 to 5% by weight, preferably 0.01 to 1% by weight, based on the total amount of used paper. In addition, the said weight% is a value of solid content conversion.

  The nonionic surfactant is not particularly limited, and various known nonionic surfactants can be used. For example, a polyether chain obtained by copolymerizing ethylene oxide and propylene oxide can be used. Examples include those obtained by binding higher saturated alcohols such as lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol. In the present invention, in particular, a nonionic surfactant “DIA-Z-5000” manufactured by Nisshin Chemical Laboratory is preferably used.

  Furthermore, it is preferable that a silicate compound is added to the solvent, and the metal complex catalyst and hydrogen peroxide are brought into contact with the waste paper pulp in the solvent. Thereby, deinking and bleaching of waste paper pulp can be performed more efficiently. The addition amount of the silicate compound is 0.1 to 10% by weight, preferably 1 to 5% by weight, based on the total amount of waste paper. Examples of the silicate compound include metasilicate sodium salt or potassium salt, orthosilicate sodium salt or potassium salt, and the like.

  Moreover, you may add the other compound used as a deinking agent component other than the said nonionic surfactant to the said solvent which concerns on this invention. Examples of such other compounds include saturated or unsaturated fatty acids having 12 to 24 carbon atoms, alkali metal salts thereof, alcohol esters having 1 to 3 carbon atoms, and sulfate esters of the nonionic surfactant. Anionic surfactants such as salts, or cationic surfactants such as compounds obtained by bonding a saturated or unsaturated alkylamine having 12 to 24 carbon atoms to a polyether chain obtained by copolymerizing ethylene oxide and propylene oxide Etc.

  As described above, the M-salen complex, which is a metal complex catalyst represented by the general formula (1) or the general formula (2), improves the deinking property without inhibiting the bleaching property of hydrogen peroxide. Therefore, it functions as a deinking aid used to remove residual ink from waste paper pulp. Therefore, the deinking assistant according to the present invention is represented by the general formula (1) or the general formula (2).

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to a following example.

The M-salen complexes, which are metal complex catalysts used in the following examples, are the following three types.
<Synthesis Example 1: Synthesis of Mn-salen complex (1a)>
10.0 g of salicylaldehyde and 2.46 g of ethylenediamine were mixed in methanol and stirred for 30 minutes. Subsequently, this solution was concentrated under reduced pressure to recover the deposited salen ligand. The recovered salen ligand (1.00 g) and manganese (II) acetate tetrahydrate (0.913 g) were dissolved in methanol and heated to reflux for 30 minutes under atmospheric exposure. Then, this solution was concentrated under reduced pressure and cooled to 5 ° C. to obtain Mn-salen complex (1a) [in the structural formula represented by the general formula (1), M = Mn (III), X = CH ₃ COO ⁻ (Acetate ion), R _{1 to} R ₇ = H (hydrogen atom)] were obtained as crystals (yield 77%).

<Synthesis Example 2: Synthesis of Mn- (Ph-salen) complex (1b)>
10.0 g of salicylaldehyde and 4.43 g of 1,2-phenylenediamine were mixed in methanol and reacted for 30 minutes while being heated to 50 ° C. The solution after the reaction was concentrated under reduced pressure to recover the precipitated Ph-salen ligand. The recovered Ph-salen ligand (1.00 g) and manganese (II) acetate tetrahydrate (0.775 g) were dissolved in methanol and heated to reflux for 30 minutes while blowing air. Subsequently, this solution was concentrated under reduced pressure, and Mn- (Ph-salen) complex (1b) [in the structural formula represented by the general formula (1), M = Mn (III), X = CH ₃ COO ⁻ , R _{1 to} R ₅ = H, R ₆ and R ₇ = (= CH—CH═CH—CH =: R ₆ and R ₇ combine with each other to form a benzene ring)] as a precipitate (yield 86 %). Incidentally, Mn- (Ph- salen) complex (1b), the structural formulas represented by the general formula (2), M = Mn ( III), X = CH 3 COO -, with R ₁ ~R ₅ = H is there. The Ph means a phenyl group.

<Synthesis Example 3: Synthesis of Mn- (Me ₄ -salen) complex (1c)>
10.0 g of salicylaldehyde and 4.76 g of 2,3-diamino-2,3-dimethylbutane were mixed in methanol and reacted for 30 minutes. The solution after the reaction was concentrated under reduced pressure to recover the deposited Me ₄ -salen ligand. The recovered Me ₄ -salen ligand (1.00 g) and manganese (II) acetate tetrahydrate (0.755 g) were dissolved in methanol and heated to reflux for 30 minutes while blowing air. Next, this solution was concentrated under reduced pressure, and Mn- (Me ₄ -salen) complex (1c) [in the structural formula represented by the general formula (1), M = Mn (III), X = CH ₃ COO ⁻ , to give R ₁ ~R ₅ = H, the _{R 6 = CH 3, R 7} = CH 3] as a precipitate (86% yield). In addition, said Me means a methyl group.

The waste paper pulp was subjected to ink removal treatment and bleaching treatment under the following conditions. The solvent is [Takatsuki City tap water (hereinafter abbreviated as city water)], and the surfactant is a nonionic surfactant “DIA-Z-5000” manufactured by Nissin Chemical Laboratory. used. The added amount of DIA-Z-5000 is a value in terms of solid content.
<Recycled paper pulp processing experimental conditions>
Used paper: Mixture of 72 g of used newspaper and 48 g of newspaper folded leaflet Addition amount of metal complex catalyst: 0.50,100 ppm (total amount of used paper)
Hydrogen peroxide addition amount: 2.0% by weight (total amount of used paper)
Sodium hydroxide addition amount: 0.8% by weight (total amount of used paper)
Sodium metasilicate addition amount: 1.6% by weight (waste paper total amount)
DIA-Z-5000: 0.2% by weight (total amount of used paper)
Pulp concentration: 10% by weight (against city water and waste paper)
Reaction temperature: 40 ° C
Reaction time: 20 minutes

<Recycled paper pulp processing experiment>
Place the above-mentioned waste paper 120g, city water 1080g, sodium hydroxide, sodium metasilicate, DIA-Z-5000 in a heat-retaining container of a disintegrator with a processing capacity of 2 liters (set so that the internal liquid temperature is 40 ° C). A fixed amount was added. Subsequently, the disintegrator was operated at a stirring speed of 1000 rpm and disaggregated for about 2 minutes to produce a 10% strength by weight waste paper pulp. Then, a predetermined amount of metal complex catalyst [Mn-salen complex (1a), Mn- (Ph-salen) complex (1b), Mn- (Me ₄ -salen) complex (1c)] and hydrogen peroxide are added in this order. The reaction was continued while disaggregating for another 20 minutes.

Waste paper pulp after the reaction was washed with city water to remove free impurities such as ink. Using 3.0 g (solid content) of this pulp (deinked pulp), a sample paper piece for measuring the residual ink area ratio and the whiteness was measured in accordance with the papermaking method defined in Japanese Industrial Standard JIS-P-8222. The paper was made on a circular wire (basis weight was 150 g / m ² ).

About the sample paper piece produced above, the deinking property and bleaching property of waste paper pulp were evaluated. Each evaluation method is shown below, and the results are shown in Table 1.
<Evaluation method of deinking property>
The deinking property of waste paper pulp was evaluated from the residual ink area ratio of the prepared sample paper pieces. Specifically, the residual ink area ratio was measured using LUZEX-AP manufactured by Nireco Corporation.
<Bleaching evaluation method>
The bleaching property of waste paper pulp was evaluated from the whiteness of the sample paper pieces prepared. Specifically, based on the measurement method of ISO whiteness defined by Japanese Industrial Standard JIS-P-8148, it was measured using ERP-80WX manufactured by Tokyo Denshoku.

Test No. using metal complex catalyst Test Nos. 2 to 7 are samples outside the scope of the present invention. In each case, a decrease in the ink area ratio after the reaction was confirmed. From this, the metal complex catalyst [Mn-salen complex (1a), Mn- (Ph-salen) complex (1b), Mn- (Me ₄ -salen) complex (1c)] according to the present invention is hydrogen peroxide. It can be seen that the deinking property is improved without impairing the bleaching property. In any of the complexes, the degree of reduction was larger when 100 ppm was added than when 50 ppm was added.

The change in the ink area ratio with the addition amount of the metal complex catalyst is shown in FIG. As apparent from Table 1 and FIG. In 2 to 7, it was found that the ink area ratio decreased. The area ratio decreased the most in Test No. No. 7 Mn— (Me ₄ -salen) complex was used in an amount of 100 ppm. It decreased from 2.48% which is the measurement result of 1 to 1.83%, which is 0.65% less. In addition, test No. 1 using Mn-salen complex was conducted. 3 decreased to 2.26%, and the decrease was 0.22%. Test No. using Mn— (Ph-salen) complex 5 decreased to 2.20%, and the decrease was 0.28%.

Moreover, the change with the addition amount of the metal complex catalyst of whiteness was shown in FIG. As apparent from Table 1 and FIG. 2, test No. 1 containing 100 ppm of Mn— (Me ₄ -salen) complex was added. The whiteness of 7 was greatly improved, and the effect of promoting the bleaching reaction by the metal complex catalyst was recognized. That is, test no. It can be seen that the Mn— (Me ₄ -salen) complex according to No. 7 improves the bleaching property in addition to the improvement of the deinking property.

Test No. using metal complex catalyst Among the test Nos. 2 to 7, the effect of improving the whiteness was observed. 7. In addition, Test No. 3 also had the highest effect of reducing the ink area ratio. 7 indicates that the Mn— (Me ₄ -salen) complex used in this test most promotes the two effects of whiteness improvement and ink removal necessary for recycling used paper pulp.

6 is a graph showing changes in ink area ratio according to the amount of added metal complex catalyst in Example 1. 3 is a graph showing changes in whiteness according to the amount of added metal complex catalyst in Example 1. FIG.

Claims (11)

A method of removing residual ink from the pulp and bleaching the pulp fiber by contacting the waste paper pulp with a metal complex catalyst and hydrogen peroxide, wherein the metal complex catalyst is represented by the following general formula (1): A method for treating waste paper pulp, which is a (bissalicylidene) ethylenediamine complex.

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ are the same or different groups, and each is a hydrogen atom, lower alkyl group, aryl group, aralkyl group, lower alkoxy group, alkyloxycarbonyl group, aryloxy group. R ₅ represents a carbonyl group, a halogen atom, a trimethylsilyl group, an aryloxy group, an acyloxy group, an acyl group, a nitro group, a hydroxyl group, a carboxyl group, a carboxylate group (carboxylate), a carbamoyl group, a formyl group, or a cyano group. , A hydrogen atom, a lower alkyl group, an aryl group or an aralkyl group, R ₆ and R ₇ are the same or different groups, each representing a hydrogen atom, a lower alkyl group or an aryl group, and further R ₆ and R _7. May combine with each other to form a saturated or unsaturated hydrocarbon ring, and M has an oxidation number of + III. A transition metal, X is a monovalent anion.)   The method for treating waste paper pulp according to claim 1, wherein M in the general formula (1) represents Mn (III), Fe (III), Ru (III), Co (III) or Mo (III). In the general formula (1), R _{1 to} R ₅ represent a hydrogen atom, R ₆ and R ₇ represent a hydrogen atom, a lower alkyl group, or the unsaturated hydrocarbon ring is a benzene ring, and M represents Mn (III The method for treating waste paper pulp according to claim 1 or 2, wherein the monovalent anion in X represents a carboxylate ion. In the general formula (1), R _{1 to} R ₅ represent a hydrogen atom, R ₆ and R ₇ represent a lower alkyl group, M represents Mn (III), and the monovalent anion in X represents a carboxylate ion. The processing method of the used paper pulp in any one of Claims 1-3 shown. A method of removing residual ink from the pulp and bleaching the pulp fiber by contacting the waste paper pulp with a metal complex catalyst and hydrogen peroxide, wherein the metal complex catalyst is represented by the following general formula (2): A method for treating waste paper pulp, which is a (bissalicylidene) ethylenediamine complex.

(Wherein R _{1 to} R ₅ , M and X are as defined in claim 1).   The method for treating waste paper pulp according to any one of claims 1 to 5, wherein the metal complex catalyst and hydrogen peroxide are contacted with the waste paper pulp in a solvent.   The method for treating waste paper pulp according to claim 6, wherein sodium hydroxide is added to the solvent, and the metal complex catalyst and hydrogen peroxide are contacted with the waste paper pulp in the solvent.   The method for treating waste paper pulp according to claim 6 or 7, wherein a nonionic surfactant is added to the solvent, and the metal complex catalyst and hydrogen peroxide are contacted with the waste paper pulp in the solvent.   The method for treating waste paper pulp according to any one of claims 6 to 8, wherein a silicate compound is added to the solvent, and the metal complex catalyst and hydrogen peroxide are brought into contact with the waste paper pulp in the solvent.   The deinking aid represented by the general formula (1) according to any one of claims 1 to 4, which is used for removing residual ink from waste paper pulp. The deinking aid represented by the general formula (2) according to claim 5, which is used for removing residual ink from waste paper pulp.

Images