JPH06299488A - High concentration aqueous dispersion composition of raw material for pulp digesting agent - Google Patents

Abstract

PURPOSE:To provide a high concentration aqueous dispersion composition capable of most efficiently supplying a raw material THAQ for a pulp digesting agent to a digesting process and having the same stable digesting effect and dispersibility as a dialkali salt aqueous solution of an ordinary digesting agent DDA even in the case of dissolution in an alkaline solution. CONSTITUTION:A THAQ solution is obtained by dispersing powders of <=50mum in an average diameter obtained by wet pulverization by using >=1% of oxyethylene-oxypropylene block copolymer as a dispersing agent in a concentration of >35%. This dispersed raw material THAQ of >35% can be used as a dialkali salt of a digesting agent DDA, as it is, in the form of a high- concentration aqueous dispersion, the dialkali salt having a stable digesting effect and dispersibility.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-concentration aqueous dispersion composition of a raw material for a pulp cooking aid which is used by dissolving it in an alkaline aqueous solution in a method of digesting a lignocellulosic material with an alkaline pulping liquid. .

[0002]

2. Description of the Related Art Increasing the yield of chemical pulp is an important issue for the effective use of wood resources. As one of the techniques for increasing the yield of kraft pulp, which is the mainstream of chemical pulp, quinone-based chemicals are used. There is an alkaline pulping liquor digestion method (edited by the Japan Paper Pulp Technology Association, progress in kraft pulp / non-wood pulp (enhanced) kraft pulp production) to be added.

In summary, in the method of digesting a lignocellulosic material with an alkaline pulping liquid, a quinone-based agent that can be used is anthraquinone (hereinafter referred to as "AQ") which is insoluble in both water and alkaline aqueous solutions.
Say. ), THAQ which is insoluble in water but soluble in an alkaline aqueous solution, and THAQ is dissolved in an alkaline aqueous solution and isomerized to 1,4-dihydro-9,10-dihydroxyanthracenes (hereinafter referred to as “DDA”). There are quinone-based agents such as DDA dialkali salts as aqueous solutions, and among these quinone-based agents, AQ and DDA dialkali salts are put to practical use.

The addition of these quinone chemicals as a pulp cooking aid is effective for any of the pulp cooking methods such as the so-called kraft method, low sulfidity kraft method, alkali method, and polysulfide method. It can be expected to improve the yield, shorten the cooking time, reduce the amount of added alkali, and can perform pulp cooking by the low sulfidity kraft method and the alkali method without impairing the pulp quality. It can be widely expected that the odor emission load of pulp cooking can be reduced, and that the deodorizing alkali method pulp cooking can be realized.

The dialkali salt of DDA (the amount added as DDA) and the amount of AQ added as auxiliaries of the quinone type drug DDA are 0.1 to the lignocellulosic material to be cooked.
The content is not more than 10% by weight, and each is used as an aqueous solution of a dialkaline salt of DDA, or as a powder of AQ as it is or as an aqueous dispersion composition of AQ, added to a pulp cooking step.

[0006]

THAQ as a raw material of dialkali salt of quinone type drug DDA used here
Is easily synthesized by the Diels-Alder reaction between butadiene and naphthoquinone, and THAQ is dissolved in an alkaline aqueous solution and isomerized to DDA, and exists as an aqueous solution of a dialkali salt of DDA. Since the DDA dialkali salt is water-soluble, it is convenient to add and use it as a cooking aid, but the concentration of the aqueous solution that can be handled stably is as low as 25% or less at room temperature (Japanese Patent Publication No. 4-855).
3) In addition, there is a problem that it is easily oxidized by being exposed to air during handling or reacting with dissolved oxygen in the liquid to form insoluble solid AQ which is difficult to handle.

[0007] On the other hand, THAQ is isomerized to DDA in an alkaline aqueous solution and easily oxidized, but it is known that THAQ is stable and hardly oxidized even in the presence of air in neutral water ( JP-B-62-62195).

Therefore, paying attention to THAQ, the aqueous dispersion composition of the pulp cooking aid raw material is a dispersion composition prepared at a high concentration that can be easily handled, and when used, DDA is used. There is a need for a quinone-based pulp cooking aid dissolved in an alkaline aqueous solution so that the dialkali salt can exhibit the stable cooking effect and excellent dispersibility.

For example, THAQ having an average particle size of 300 micrometers or less is dispersed in water so that the concentration thereof is 35% by weight or less, and the obtained slurry is mixed with an aqueous solution of alkali hydroxide to eliminate oxygen. Below, 70-100 ℃
A method (Japanese Examined Patent Publication No. 62-62195) in which the obtained aqueous solution is dissolved in and is supplied to the digestion step is known, but the concentration in water that can be stably handled is as low as 35% by weight or less, and alkali Even when redissolved in an aqueous solution, as described above, in order to exert the characteristics of the DDA dialkali salt having a stable cooking effect and dispersibility, a polyhydric alcohol alkylene oxaside adduct having a concentration of 1% or less is used. Even when added as a surfactant, the minimum guaranteed value of the concentration that can be handled stably is limited to a low concentration of 25%, and it is unsatisfactory as a quinone pulp cooking aid.

Further, for example, in order to exhibit the stable cooking effect and excellent dispersibility of the dialkaline salt of DDA, the adduct of the higher fatty acid of polyethylene oxide polypropylene oxide copolymer at a concentration of 1% by weight or less. The method of addition (Japanese Patent Publication No. 1-20276) is known, but this is DDA as a quinone-based pulp cooking aid.
It only supports the original effect of the dialkali salt.

[0011]

In order to handle THAQ currently industrially produced as a raw material as an aqueous dispersion composition having a concentration of more than 35% by weight, 1 ppm by weight of a surfactant is contained in water. It is known that the presence of ˜1% improves the dispersibility of the THAQ raw material. Further, as the surface active agent, cationic, nonionic and anionic properties are known. For example, aliphatic sulfonates such as dioctyl succinate, dodecylbenzene sulfonate, formalin condensates of naphthalene sulfonate, aromatic sulfonates such as lignin sulfonate, amines such as polyoxyethylene octadecylamine, trimethyl. -Cationic surfactants such as hexadecyl-ammonium bromide, ethylene oxide and higher alcohol ethers, ethylene oxide derivatives of alkylphenol formalin condensates, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene glycol fatty acid esters, nonionics such as fatty acid alkanolamides Known as surfactants, aminocarboxylic acid salts, amphoteric surfactants such as carboxypentane type, and other known fluorochemical surfactants such as fluoroalkylcarboxylic acids. .

In the present invention, as a result of close examination, a block copolymer of oxyethyleneoxypropylene, which can also be used as the above-mentioned nonionic surfactant,
In particular, it has been found that THAQ can be made into a high-concentration aqueous dispersion composition of a pulp cooking aid raw material by allowing a concentration of more than 1% by weight to coexist in water as a dispersant and wet-milling.

This block copolymer has a molecular weight of 2,000 to 10,000, preferably 3,000 to 6,000 by controlling the molecular weight of propylene glycol hydrophobic groups and the amount of ethylene oxide added, and the amount of ethylene oxide added in the total molecule is 20 to 70%. Select and use a block copolymer.

When the THAQ raw material is dispersed in water, it is generally preferable that the particle size of THAQ is small. However, due to its economical efficiency, the average residence time of 10 minutes to 1 hour in the next alkali dissolution step. When allowed, the average particle diameter is reduced to 300 micrometers or less by using an ordinary pulverizer. However, in the present invention, the average residence time is 10 minutes or less, preferably 1 minute or less. Wet milling to an average particle size of 50 micrometers or less, preferably 30 micrometers or less.

Examples of the crusher include a ball mill in a broad sense, for example, a rolling mill, a vibrating ball mill or a planetary mill, and a stirring mill, for example, a tower type crusher, a stirring tank type mill, a flow tube type mill, An annular mill etc. are mentioned.
Wet pulverization is performed by a pulverizer selected from these fine pulverizers.

In order to prepare THAQ as a high-concentration aqueous dispersion composition of a pulp cooking aid raw material, it is generally preferable to use an aqueous dispersant having a high fluidity and a high concentration.
Since the fluidity is also affected by the crystal shape of the AQ raw material, in general, when the concentration exceeds 35% by weight, the average particle size is 50 micrometers or less, and the concentration of the aqueous dispersion composition is 50 to 75% by weight. %, It is usually wet pulverized to have an average particle size of 30 micrometers or less.

The temperature at which the aqueous dispersion composition of the THAQ raw material is usually prepared may be room temperature, but considering that it is later mixed with an alkaline aqueous solution and dissolved by heating, the temperature is not higher than the melting point of the THAQ raw material, about 50 ° C. The temperature may rise during the period.
However, a crusher with a cooling jacket is preferred so that excess heat does not accumulate.

Next, an aqueous solution of sodium hydroxide or potassium hydroxide or a cooking white liquor is used as the aqueous alkali hydroxide solution used when the aqueous dispersion composition of the THAQ raw material is supplied to an aqueous alkali hydroxide solution and mixed and heated and dissolved. Alternatively, a mixture of cooking white liquor and circulating cooking black liquor or the like is used.

Although the amount of alkali required for dissolution is 2 times the amount of the aqueous dispersion composition of the THAQ raw material to be supplied, an excessive amount is usually added to the alkaline pulping cooking chemical liquid fed by the pump. It is used as it is because of the presence of alkali. The temperature at which the solution is heated and dissolved is the temperature normally held by the alkaline pulping cooking chemical liquid fed by the pump, 6
0-80 ° C is sufficient. Mixing and dissolution by heating are necessary in order to prevent oxidation of the dialkali salt of DDA which is carried out in a closed system or in the absence of oxygen in a nitrogen atmosphere.

A practical operation of mixing the water dispersion composition of the THAQ raw material can be easily carried out by directly charging the pumped alkaline pulp cooking chemical liquid or directly supplying the liquid to the liquid supply pipe of the circulation line via a nozzle. can do. In addition, the method of supplying via a mixer such as a line mixer or a stirring tank is more reliable. For example, TH
In the method of supplying the water-dispersed composition of AQ raw material to a small-volume white liquor tank or the method of supplying it to an injector or a line mixer provided in the white liquor supply line of the cooking step, a residence time of about 1 minute or less is sufficient. . The thus obtained aqueous solution of dialkali salt of DDA was supplied to the cooking step as a uniform solution and prepared by the conventional method.
As in the case of the aqueous solution of dialkali salt, it is easy to penetrate into a lignocellulosic material, for example, wood chips as a cooking aid, and compared with the case where AQ is supplied to a digester as an aqueous dispersion composition. The water-dispersed composition of the present invention has the characteristics of stable cooking effect and excellent dispersibility by eliminating uneven dispersion on chips.

Examples of the alkaline pulp cooking liquor used in the present invention include alkaline pulping liquid cooking methods such as Kraft method, polysulfide method, gas phase cooking method, soda method and sulfite method.

The present invention most efficiently uses THAQ raw material,
As a result of studying a method of supplying the cooking aid as an aqueous solution of dialkali salt of DDA to the cooking step, a block copolymer of oxyethyleneoxypropylene having a concentration of more than 1% was used as a dispersant, and an average particle diameter of 50 was obtained by a wet grinding operation. The THAQ raw material with a concentration of more than 35% can be directly supplied by preparing to a micron or less, and the cooking aid DD
As a dialkali salt of A, it has been found that it can be handled as a high-concentration aqueous dispersion composition that exhibits a stable cooking effect and dispersibility. Hereinafter, the present invention will be described in detail with reference to Examples. However, in the present specification, "part" means "part by weight" unless otherwise specified.

[0023]

【Example】

[Experimental example 01] (Preparation of sample) As a wet pulverizer, a paint mixer (trade name of Red Devil Co.) whose pulverizing balls are glass beads was used, and 50 parts of THAQ raw material and a dispersant were used in a mill sample bottle. Five parts were taken and water was added thereto to make 100 parts, which was crushed for 30 minutes, and the particle size was measured and the dispersibility was evaluated. Dispersant used Block copolymer of oxyethyleneoxypropylene Average particle size of crushed product 10 micrometer or less (Evaluation of dispersibility) Prepared sample showing the degree of drainage of pulp A method similar to measurement of freeness, glass on a plate The time taken for the sample prepared from the beads to flow out was measured, and
Greater than 5 cm / min (Dispersibility 5), 0.1 cm
/ Minute or more is good (dispersion 4), 0.01 cm / minute or more is good (dispersion 3), partial fluidity (dispersion 2), no fluidity (dispersion 1) ), And evaluated. (Determination of cooking effect) Using a rotary 200 ml autoclave, ordinary craft cooking conditions, sulfidity 3
0%, cooking temperature 170 ° C, cooking time 97 minutes, heating time 4
5 minutes, fixed active alkali addition rate of 16.5% and blank active alkali addition rate of 18% for judging the effect of saving alkali, fixed to 25 points each of domestic pine wood
Grams were used as test materials and the cooking results obtained were compared.
Shown in [Table 01] are the evaluation values of the cooking results of (cooking effect 5).

[0024]

[Table 01]

A predetermined amount of the prepared highly concentrated aqueous dispersion composition of the THAQ raw material was mixed with the alkaline pulp cooking chemicals and cooked. As a result, the cooking effect and dispersibility of Experimental Example 01 were very good (evaluation cooking effect 5, dispersibility 5).

[Experimental Example 02] Using the same tester as in Experimental Example 01, 50 parts of THAQ raw material and 2 parts of dispersant were placed in the mill sample bottle, and water was added to 100 parts to pulverize for 30 minutes. The method of determining dispersibility and cooking effect was Experimental Example 0.
Same as 1. Dispersant used Block copolymer of oxyethyleneoxypropylene Average particle size of ground product 10 micrometer or less Cooking effect and dispersibility Very good (Evaluation cooking effect 5, dispersibility 5)

[Experimental Example 03] Using the same tester as in Experimental Example 01, 50 parts of THAQ raw material and 1.5 parts of dispersant were placed in the mill sample bottle, and water was added to 100 parts to make 3 parts.
Grind for 0 minutes. The methods for determining dispersibility and cooking effect are the same as in Experimental Example 01. Dispersant used Block copolymer of oxyethyleneoxypropylene Average particle size of crushed product 10 micrometer or less Cooking effect and dispersibility Very good (evaluation cooking 5, dispersibility 5)

[Experimental Example 04] Using the same tester as in Experimental Example 01, 50 parts of THAQ raw material and 1 part of dispersant were placed in the mill sample bottle, and water was added to make 100 parts, and the mixture was pulverized for 30 minutes. The method of determining dispersibility and cooking effect was Experimental Example 0.
Same as 1. Dispersant used Block copolymer of oxyethyleneoxypropylene Average particle size of crushed product 10 micrometer or less Good cooking effect and dispersibility (evaluation cooking 5, dispersibility 4)

[Experimental Example 05] Using the same tester as in Experimental Example 01, 50 parts of THAQ raw material and 0.5 part of dispersant were placed in the mill sample bottle, and water was added to 100 parts to make 3 parts.
Grind for 0 minutes. The methods for determining dispersibility and cooking effect are the same as in Experimental Example 01. Dispersant used Block copolymer of oxyethyleneoxypropylene Average particle size of crushed product 10 micrometer or less Poor cooking effect and dispersibility (evaluation cooking 5, dispersibility 1)

[Experimental Example 06] Using the same tester as in Experimental Example 01, 60 parts of THAQ raw material and 1.8 parts of dispersant were placed in the mill sample bottle, and water was added to 100 parts to make 3 parts.
Grind for 0 minutes. The methods for determining dispersibility and cooking effect are the same as in Experimental Example 01. Dispersant used Block copolymer of oxyethyleneoxypropylene Average particle size of crushed product 10 micrometer or less Cooking effect and dispersibility Very good (evaluation cooking 5, dispersibility 5)

[Experimental Example 07] Using the same tester as in Experimental Example 01, 65 parts of THAQ raw material and 1.3 parts of dispersant were placed in the mill sample bottle and water was added to 100 parts to make 3 parts.
Grind for 0 minutes. The methods for determining dispersibility and cooking effect are the same as in Experimental Example 01. Dispersant used Block copolymer of oxyethyleneoxypropylene Average particle size of crushed product 10 micrometer or less Good cooking effect and dispersibility (evaluation cooking 5, dispersibility 4)

[Experimental Example 08] Using the same tester as in Experimental Example 01, 70 parts of THAQ raw material and 3.3 parts of dispersant were placed in the mill sample bottle, and water was added to 100 parts to make 3 parts.
Grind for 0 minutes. The method for determining the cooking effect is the same as in Experimental Example 01. Dispersant used Block copolymer of oxyethylene oxypropylene Average particle size of crushed product 10 micrometer or less Good cooking effect and dispersibility (evaluation cooking 5, dispersibility 3)

[Experimental Example 09] Using the same tester as in Experimental Example 01, 75 parts of THAQ raw material and 3.7 parts of a dispersant were placed in the mill sample bottle, and water was added to 100 parts to make 3 parts.
Grind for 0 minutes. The methods for determining dispersibility and cooking effect are the same as in Experimental Example 01. Dispersant used Block copolymer of oxyethylene oxypropylene Average particle size of crushed product 10 micrometer or less Good cooking effect and dispersibility (evaluation cooking 5, dispersibility 3)

[Experimental Example 10] Using the same tester as in Experimental Example 01, 30 parts of THAQ raw material and 1.5 parts of dispersant were placed in the mill sample bottle, and water was added to 100 parts to make 3 parts.
Grind for 0 minutes. The methods for determining dispersibility and cooking effect are the same as in Experimental Example 01. Dispersant used Naphthalene sulfonate formaldehyde condensate Grinded product Average particle size 10 micrometer or less Good cooking effect and dispersibility (evaluation cooking 5, dispersibility 4)

[Experimental Example 11] Using the same tester as in Experimental Example 01, 40 parts of THAQ raw material and 2 parts of dispersant were placed in the mill sample bottle, water was added to 100 parts, and the mixture was pulverized for 30 minutes. The method of determining dispersibility and cooking effect was Experimental Example 0.
Same as 1. Dispersant used Naphthalene sulfonate formaldehyde condensate Grinded product Average particle size 10 micrometer or less Good cooking effect and dispersibility (evaluation cooking 5, dispersibility 4)

[Experimental Example 12] Using the same tester as in Experimental Example 01, 50 parts of THAQ raw material and 2.5 parts of dispersant were placed in the mill sample bottle, and water was added to 100 parts to make 3 parts.
Grind for 0 minutes. The methods for determining dispersibility and cooking effect are the same as in Experimental Example 01. Dispersant used Naphthalenesulfonate formaldehyde condensate Average particle size of crushed product 10 micrometer or less Poor cooking effect and dispersibility (evaluation cooking 5, dispersibility 1)

The experimental conditions and the judgment results of the above [Experimental Examples 1 to 12] are summarized in [Table 01].

[0038]

[Table 02]

[0039]

INDUSTRIAL APPLICABILITY According to the present invention, water is used in alkaline pulping liquid digestion methods such as Kraft method, polysulfide method, gas phase cooking method, soda method, and sulfite method for cooking lignocellulosic material with alkaline pulping liquid. Highly concentrated THAQ which can be used as a dialkali salt of DDA, which is the best quinone-based cooking aid as an aqueous solution, by dissolving THAQ, which is insoluble in water, but is soluble in an alkaline aqueous solution, is isomerized to DDA by being dissolved in the alkaline aqueous solution. It is possible to provide a practical aqueous dispersion composition of a raw material.

[Procedure amendment]

[Submission date] November 17, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Chemical 1]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction content]

[0024]

[Table 01]

Claims (4)

[Claims] 1. A pulp cooking aid raw material, 1, 4, 4a, 9
A-tetrahydroanthraquinone (hereinafter referred to as "THAQ") was wet pulverized to have an average particle size of 50 micrometers or less in the presence of a polymer dispersant having a concentration of more than 1% by weight to obtain a concentration of 35% by weight. A high-concentration water-dispersed composition of a pulp cooking aid raw material, which was prepared to have a concentration of more than 10%. 2. The polymer dispersant has the general formula (subscripts a, b,
c is a numerical value indicating the degree of polymerization) [Chemical Formula 1] is a nonionic oxyethyleneoxypropylene block copolymer, characterized by being wet-ground in the presence of a block copolymer having a degree of polymerization of 2500 to 10000. A high-concentration aqueous dispersion composition of the pulp cooking aid raw material according to claim 1. [Chemical 1] 3. The pulp digestion aid raw material according to claim 1, wherein the pulverizer is wet pulverized by a fine pulverizer selected from a ball mill or a stirring mill in a broad sense to prepare it to a predetermined average particle size. Highly concentrated aqueous dispersion composition. 4. A method for digesting a lignocellulosic material with an alkali pulping liquid, wherein a high-concentration water-dispersed composition of the pulp cooking aid raw material according to claim 1 prepared in a required amount,
A method for cooking with an alkaline pulping liquid, which is characterized in that the alkaline pulping liquid, which is usually fed by a pump, is directly supplied, dissolved and digested.