JP5649376B2 - Defoamer for kraft pulp manufacturing process - Google Patents

Description

  The present invention relates to an antifoaming agent in a kraft pulp manufacturing process.

  Conventionally, a large amount of an antifoaming agent has been used to suppress foaming in the kraft pulp manufacturing process. In particular, foaming in the kraft pulp manufacturing process has become a problem due to lack of seasoning due to a decrease in storage chips in order to reduce Kurashiki materials. In recent years, cases of blending acacia wood are increasing when pulping hardwood. It is known that an acacia material has a larger amount of resin and a longer alkyl chain length than the eucalyptus material that has been used so far. For this reason, in the kraft pulp manufacturing process, the resin is hydrolyzed under high-temperature and high-alkaline conditions, and not only a large amount of fatty acid soap, which is a foaming component, is generated, but also foam that is hard and hard to disappear is generated due to the influence of long-chain fatty acid soap. . Currently, when acacia wood is highly blended in the hardwood kraft pulp manufacturing process, the amount of defoaming agent currently used increases, the production unit increases, and pitch trouble occurs frequently in the papermaking process. The tendency to do is seen. Some factories have doubled the amount of defoamer used and the amount of pitch generated in the papermaking process, especially by blending 5% acacia wood.

As a defoaming agent for kraft pulp manufacturing process, a polyoxyalkylene compound is used in Patent Document 1, but the content of ethylene oxide is high, and although there is an immediate effect in the stability and defoaming test against black liquor, It is inferior in the foam suppression effect (sustainability) in 2 minutes or more. Moreover, the immediate effect is improved by mix | blending silicone, and the effect as surfactant independent is inferior.
No case of using a surfactant-based antifoaming agent has been confirmed in actual factories.

JP-A-11-276806

  The problem to be solved by the present invention is that during hardwood pulp production, it is possible to avoid foaming troubles in the kraft pulp production process in which acacia materials are blended, and further aggregation of fatty acids in black liquor, organic acids such as resin acids and lignin The present invention relates to an antifoaming agent capable of suppressing the amount of generated matter.

As a result of intensive studies in order to solve the above problems, the present inventors have found that an antifoaming agent comprising a specific alkylene oxide adduct can solve the above problems, and have completed the present invention. That is, this invention relates to the antifoamer for kraft pulp manufacturing processes containing the alkylene oxide adduct whose HLB of griffin is 1-6 represented by following General formula (1).

R ₁ O (AO) _n H (1)

(In the formula, R ₁ represents an alkyl group having 8 to 22 carbon atoms, an alkenyl group, or an aryl group having 6 to 30 carbon atoms, AO represents an alkyleneoxy group having 2 to 4 carbon atoms, and n represents an integer of 1 to 100. Is shown.)

  The present invention can provide an antifoaming agent that exhibits an excellent antifoaming effect in the kraft pulp manufacturing process. In addition, the antifoaming agent of the present invention can suppress the amount of aggregates of organic substances such as fatty acids, resin acids and lignin in the black liquor.

Below, the antifoamer for kraft pulp manufacturing process of this invention is explained in full detail.
In the general formula (1), R ₁ is an alkyl group having 8 to 22 carbon atoms, an alkenyl group, or an aryl group having 6 to 30 carbon atoms, preferably an alkyl group or alkenyl group having 14 to 18 carbon atoms. is there. The alkyl group and alkenyl group having 8 to 22 carbon atoms may be linear or branched, and may have a cyclic structure.

  In the general formula (1), AO represents an alkyleneoxy group having 2 to 4 carbon atoms, and specific examples include an ethyleneoxy group, a propyleneoxy group, and a butyleneoxy group. n represents the repeating number of the alkyleneoxy group, and is an integer of 1 to 100, but a range of 20 to 50 is preferable. When n is 2 or more, it is essential that at least one ethyleneoxy group is present in the repeating unit, and when it has a propyleneoxy group or a butyleneoxy group, it may have only one of them. And you may have both. When it has two or more types of alkyleneoxy groups, they may be added randomly or in a block form.

  The alkylene oxide adduct according to the present invention can be synthesized by adding alkylene oxide to a monohydric alcohol or monohydric phenol. Examples of monohydric alcohols include octyl alcohol, decyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, oleyl alcohol, behenyl alcohol, alkylcyclohexanol, etc. A cyclic alcohol etc. are mentioned. Examples of the monohydric phenol include mono-di-tristyrenated phenol, mono-di-tribenzylphenol, octylphenol, nonylphenol, dinonylphenol, and cashew nut-derived alkenylphenol (cardanol). These can use 1 type (s) or 2 or more types.

  In the alkylene oxide adduct according to the present invention, when the ethyleneoxy group is a hydrophilic group, the propyleneoxy group and the butyleneoxy group are hydrophobic groups, it is desirable to adjust the alkyleneoxy group so that the HLB of Griffin is 1 to 6. More preferably, it is 2-5. If the HLB exceeds 6, the dispersion effect of the organic matter in the black liquor is enhanced, but the defoaming effect is lost, and conversely, it causes foaming. On the other hand, if the HLB is less than 1, the antifoaming agent itself aggregates and no defoaming effect can be obtained.

  The expression time of the defoaming effect can be adjusted by the addition form of the alkyleneoxy group. For example, when propylene oxide is added after adding ethylene oxide to monohydric alcohol, monohydric phenol, etc., sustainability (foam suppression effect) is obtained, and conversely when ethylene oxide is added after adding propylene oxide Immediate effect (bubble breaking effect) is obtained. On the other hand, when added randomly, an antifoaming agent having both immediate effect and sustainability can be obtained.

  The alkylene oxide adduct represented by the formula (1) contained in the antifoaming agent of the present invention may be produced by any method. Usually, it can obtain by the method of adding an alkylene oxide to a hydroxyl group under a basic catalyst.

  The antifoaming agent of the present invention has no problem even if it is mixed with water, a surfactant-based emulsifier, a water-soluble organic solvent and the like when it is commercialized.

  By using the antifoaming agent of the present invention, an excellent effect is exhibited in the manufacturing process of hardwood kraft pulp. However, particularly when 5% or more of acacia wood is blended, a defoaming effect to be noted is obtained.

  The place of addition of the antifoaming agent of the present invention is not particularly limited, but in the kraft pulp manufacturing process, it is added at the suction port of a blow tank, Jansson screen, a selective screen, a washing machine, a filtrate tank, or a pump installed in each process. It is desirable to do. Although the addition amount of the antifoamer of this invention is influenced by the foaming state of a process, it is 1-100 ppm normally with respect to a pulp, Preferably it is 2-50 ppm. Moreover, a cooking aid, a pitch control agent, a cleaning agent, etc. may be added to the kraft pulp manufacturing process as other chemicals. Further, there is no problem even if a mineral oil-based antifoaming agent or a silicone-based antifoaming agent is used as an auxiliary.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Production Example 1
A SUS autoclave equipped with a thermometer and a stirrer was charged with 81 g (0.3 mol) of stearyl alcohol and 1.5 g of 96% caustic potash, and 66 g (1.5 mol) of ethylene oxide while maintaining 155 ± 5 ° C. in a nitrogen atmosphere. ) Was gradually introduced, followed by aging for 1 hour. Thereafter, the mixture was cooled to 135 ° C., and 435 g (7.5 mol) of propylene oxide was gradually introduced while maintaining the same temperature. After aging for 3 hours at the same temperature, the caustic potash of the catalyst was neutralized with 1.7 g of acetic acid.
With this reaction, the antifoaming agent No. 1 in the reference example having a hydroxyl value of 29 mgKOH / g was used. 1 compound was obtained.

In the same manner, the antifoaming agent No. 1 of the present invention shown in Table 1 is used . 4 to 6, 10 to 12, 16 to 26, and antifoam No. 2, 3, 7-9 , 13-15 were obtained.
In Table 1,-(hyphen) in the alkylene oxide adduct indicates block addition, and / (slash) indicates random addition.

  In order to make a comparison with the antifoaming agent, the antifoaming agents shown in Table 2 were used for the test.

Performance evaluation test (circulation test)
Using an apparatus as shown in FIG. 1, the defoaming effect on the black liquor was confirmed.

Test method 1L of black liquor was added to the circulation tester in Fig. 1 and adjusted to 80 ° C. Then, the black liquor was circulated with a water pump and defoaming agent (10ppm) was added when the foam height reached 150mm (flow rate 10L) / Min). After the addition of the antifoaming agent, the foam height (mm) after 30 seconds, 1 minute, 5 minutes and 10 minutes was measured.

Performance evaluation test 1 (hardwood black liquor; 7% acacia wood)
Obtain hardwood digestion extract from paper company (black liquor concentration 20%). This extract was diluted to 5% with ion-exchanged water to obtain a foaming solution for evaluation.

Performance evaluation test 2 (Hardwood black liquor; 50% acacia mix)
Obtain hardwood digestion extract from paper company (black liquor concentration 22%). This extract was diluted to 5% with ion-exchanged water to obtain a foaming solution for evaluation.

Performance evaluation test 3 (dispersibility of antifoaming agent in black liquor)
200 ml of black liquor used in performance evaluation tests 1 and 2 adjusted to 80 ° C. in a 300 ml glass beaker is added, and an antifoaming agent is added and stirred for 1 hour. Then, filter with 100 mesh nylon cloth. The aggregate was separated by filtration, washed with 300 ml of warm water at 80 ° C., dried, weighed, and the aggregation rate was calculated according to the following formula.

It is a figure which shows the circulation test machine with which the test of a defoaming effect is provided.

1 Glass cylinder 2 Flow path 3 Water pump 4 Cock (Open when waste liquid)
5 Channel 6 Butt 7 Heater (IH heater)
8 Water pump

Claims (1)

Contains an alkylene oxide adduct represented by the following general formula (1) having an HLB of 3.6 to 4.7 when Griffin has a hydrophilic group, a propyleneoxy group, and a butyleneoxy group as a hydrophobic group. A defoamer for kraft pulp manufacturing process that contains Acacia wood .
R ₁ O (AO) _n H (1)
(In the formula, R ₁ represents an alkyl group having 8 to 22 carbon atoms, an alkenyl group, or an aryl group having 6 to 30 carbon atoms, AO represents an alkyleneoxy group having 2 to 4 carbon atoms, and n represents an integer of 30 to 50 . Is shown.)

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