JP2001020191A - Defoaming agent for pulp production and production of pulp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a silicone defoaming agent that has excellent initial defoaming properties and emulsion stability even under the severe conditions of high temperature and high alkalinity, causes no staining in the system and the pitch trouble in the paper-making process. SOLUTION: The component (A) comprises (I) 80-99.9 wt.% of an organopolysiloxane and (II) 0.1-20 wt.% of fine particle powder of silica, while the component (B) comprises (III) 30-99 wt.% of polyoxyalkylene-modified silicone oil and (IV) 1-70 wt.% of a polyhydric alcohol alkyl ether. The objective defoaming agent for pulp production includes (C) 0.1-50 pts.wt. of a surfactant other than polyoxyalkylene modified silicone oil and (D) 0.01-10 pts.wt. of a thickener of a water-soluble polymer per 100 pts.wt. of the sum of the component A (58-90 wt.%) and the component B (10-42 wt.%).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifoaming agent for a pulp manufacturing process and a method for producing pulp using the antifoaming agent. More specifically, the present invention relates to an antifoaming agent for a pulp manufacturing process which is effective for defoaming in a washing process and a bleaching process in which foaming phenomena frequently occur during a pulp manufacturing process, and a pulp manufacturing method using the same.

[0002]

2. Description of the Related Art Pulp is a fiber component mechanically or chemically extracted from plant tissue such as wood, and is mechanically pulp by a mechanical method, chemical pulp by a chemical method, and a composite method thereof. Classified as semi-chemical pulp. Chemical pulp is roughly classified into sulfite pulp and kraft pulp depending on the chemical used, and the latter accounts for the majority of the production.

[0003] The process of producing kraft pulp usually comprises a cooking step, a washing step, a bleaching step and a preparation step. In the cooking step, wood chips as a raw material are steamed under pressure in a mixture of sodium hydroxide and sodium sulfide to solubilize non-fiber components such as lignin, resin and organic acids in the raw material.
The cooked pulp obtained in the cooking step is sent to the washing step via a blow tank.

[0004] In the washing step, non-fiber components and residual cooking chemicals solubilized in the cooking step are removed from the pulp by washing and dewatering. The cooking liquor and the washing waste liquid removed here are generally called black liquor. As a washer (washing machine) used in the washing process, a vacuum drum washer is most widely used, and a multi-stage (counter-current rotating type) washing device in which two or three vacuum drum washers are connected in series is generally used. .

Ideally, the washing is performed while replacing the black liquor with 100% of clean water. However, in this case, a large amount of waste liquid having a low black liquor concentration is recovered, and the cost for evaporating and concentrating the waste liquid with an evaporator or the like increases. Resulting in. Therefore, it is necessary to recover the waste liquid having a high black liquor concentration while minimizing the amount of fresh water used. For example, in the case of a three-stage washing device, in order to increase the washing efficiency, the recovered black liquor of the second-stage drum washer is used for the first-stage cleaning solution (washer shower), and the collected black liquor of the third-stage drum washer is used for the second stage. A method of using clear water only for the third-stage cleaning liquid and for the third-stage cleaning liquid has been generalized.

[0006] Since the black liquor contains a foaming substance such as lignin or a sodium salt of another resin component, a foaming phenomenon occurs. Such a phenomenon is likely to occur in a cleaning process, particularly in a vat of a vacuum drum washer and a black liquor recovery tank. Due to this foaming phenomenon, not only the dewatering rate of the pulp is reduced, and the quality of the pulp itself is deteriorated, but also the pulp mass falls off the sheet without being loaded on the vacuum drum, and the operation may be stopped.

Black liquor is usually used at a temperature of 60 to 80 ° C.
Since the liquid is a high-temperature and highly alkaline liquid of H12 or higher, if the black liquor overflows from the tank due to excessive foaming, there is a problem in terms of safety. The pulp (unbleached pulp) obtained in the above washing step is then sent to the bleaching step.

In the bleaching step, the pulp is bleached by decolorizing or removing coloring components (primarily lignin and pigment-based substances) in the pulp, and further imparts physical and chemical properties suitable for each use to the pulp. . An agent such as sodium hypochlorite is used for bleaching. Although the pH of the pulp is lowered in this bleaching step, the resin component adsorbed on the pulp in the washing step, which was highly alkaline, dissolves in the bleaching solution and raises the surface tension of the bleaching solution, causing severe foaming. This foaming phenomenon causes various problems such as a decrease in the bleaching effect, a decrease in the circulation speed, and a floating or outflow of the bleaching / bleaching material.

In the preparation step, the paper is given basic properties by beating, sizing, coloring (toning), filling and the like. Specifically, pulp fibers dispersed in water are repeatedly compressed and recovered, sizing agents, fillers,
Add colorants or other agents.

[0010] Mineral oil-based antifoaming agents such as amide-based antifoaming agents have conventionally been used for the foaming phenomenon in the pulp manufacturing process as described above. The mineral oil-based antifoaming agent has an excellent defoaming effect even under high temperature and high alkalinity conditions, and the effect is stable and hardly affected by pH fluctuation.

[0011] However, there have been problems such as the fact that the active ingredient itself of the mineral oil-based antifoaming agent causes stains in the system and causes pitch trouble in the papermaking process after pulp production. The mineral oil-based defoamer is a polycyclic aromatic compound,
Since the defoaming effect by adding a small amount is low and a large amount of addition is required to obtain a desired defoaming effect, it is not preferable from an environmental point of view.

On the other hand, a silicone-based foam suppressing composition has been proposed as an antifoaming agent which provides excellent defoaming continuity even under high temperature and high alkalinity conditions and does not cause the above-mentioned contamination or pitch trouble in the system. (See JP-A-7-289803 and JP-A-8-323107).

However, the compositions described in these publications are foam suppressing type antifoaming agents which are characteristic of silicone-based antifoaming agents, and therefore have a weak ability to suppress a sudden and large amount of foaming. However, there was a problem that the pulp could not be sufficiently dewatered in the subsequent step. Such a conventional silicone-based antifoaming agent is intended to improve any of the initial foam-breaking property, the foam-suppressing continuity, and the emulsion stability, and an antifoaming agent capable of simultaneously improving these three points. Development was desired.

[0014]

SUMMARY OF THE INVENTION The present invention is excellent in initial foam breaking property, foam sustainability and emulsion stability even under severe conditions of high temperature and high alkalinity, and is effective in preventing contamination in the system and pitch trouble in the paper making process. It is an object to obtain an excellent silicone-based defoaming agent that does not generate.

[0015]

Means for Solving the Problems The inventors of the present invention provide:
In view of the above problems, as a result of intensive research aimed at developing a better silicone-based antifoaming agent in the pulp manufacturing process, by using a specific composition, the conventional mineral oil-based antifoaming agent In comparison, a remarkable defoaming effect can be obtained with an addition amount of 1/3 to 1/10, and all of the initial foam breaking property, foam suppression persistence and emulsion stability can be improved, and furthermore, dirt and pitch It has been found that a remarkable effect is obtained that does not cause a trouble and does not adversely affect the dewatering efficiency and, consequently, the product quality, and the present invention has been completed.

According to the present invention, (A) the following components
Oil compound 5 comprising (I) and component (II)
8 to 90% by weight, (I) [R¹ _ThreeSiO_1/2] [R¹ _TwoSiO_2/2] [R¹ ₁S
iO_3/2]_3/2 (Wherein each R¹Are the same or different and have 1 to 20 carbon atoms
Which is a monovalent organic group).
The composition ratio is [R¹ _ThreeSiO_1/2]: [R¹ _TwoSi
O _2/2]: [R¹ ₁SiO_3/2]_3/2= 0.1-5: 90
９９99.8: 0.1 to 5 (mol%) at 25 ° C.
Having a viscosity of 100 to 1,000,000 cP
80 to 99.9% by weight of ganopolysiloxane (II) 0.1 to 20% by weight of finely divided silica (B) Mixture of the following components (III) and (IV)
10 to 42% by weight, (III) the following structural formula (1):

[0017]

Embedded image

Wherein each R ² is the same or different and is a monovalent organic group having 1 to 20 carbon atoms, and A is —R ³ —O
(CH ₂ CH ₂ O) _p [CH ₂ CH (CH ₃ ) O] _q −
R ⁴ (where R ³ is a divalent hydrocarbon group having 1 to 4 carbon atoms, R ⁴ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an acyl group or an isocyano group; ≤p
+ Q ≦ 100, 10: 90 ≦ p: q ≦ 100: 0) and a and b are 10 ≦ a + b ≦
1,000, 50: 50 ≦ a: b ≦ 99: 1, and c is 0 or 1] at 25 ° C.
Polyoxyalkylene-modified silicone oil having a viscosity of 100 to 1,000,000 cP at 30 to 99 cP.
(IV) 1 to 70% by weight of a polyhydric alcohol alkyl ether having a molecular weight of 50 to 500

Total amount of component (A) and component (B) 10
0.1 to 50 parts by weight of surfactant (C) other than polyoxyalkylene-modified silicone oil,
And (D) a thickener comprising a water-soluble polymer 0.01 to 0.01
An antifoaming agent for a pulp production process, characterized in that 10 parts by weight are dispersed in water.

Further, according to the present invention, there is provided a method for producing pulp, characterized by adding the above-mentioned antifoaming agent to process water in a pulp production process.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The oil compound of the component (A) in the antifoaming agent (hereinafter referred to as "antifoaming agent") for the pulp production process of the present invention is a main component of the antifoaming agent, It comprises the organopolysiloxane of (I) and the finely divided silica of component (II).

The organopolysiloxane of the component (I) comprises the above structural units, and R ^{1 in} this structural unit is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl Alkyl groups such as tetradecyl, hexadecyl and octadecyl; cycloalkyl groups such as cyclohexyl; alkenyl groups such as vinyl and allyl; aryl groups such as phenyl and tolyl; and one of the hydrogen atoms bonded to the carbon atoms of these groups. A substituted or unsubstituted monovalent hydrocarbon having 1 to 20 carbon atoms, such as chloromethyl, 3-chloropropyl, 3,3,3-trifluoropropyl and cyanoethyl, part or all of which is substituted with a halogen atom and a cyano group; Groups (organic groups). R ¹
May be the same or different for each unit, but preferably 90% by mole or more of the total is a methyl group.

The composition ratio of the structural units, [R ¹ ₃ Si
_{^{O 1/2]: [R 1 2}} SiO 2/2]: [R 1 1 SiO 3/2]
_3/2 = 0.1 to 5:90 to 99.8: 0.1 to 5 (mol%), preferably 1 to 3:94 to 98: 1 to 3 (mol%). If it is less than [R ¹ ₃ SiO _1/2] 0.1 mol%, the viscosity becomes high, it is not preferable because handling becomes difficult, when it exceeds 5 mol%, the viscosity is low, depression It is not preferable because the foaming property becomes poor.

When the content of [R ¹ ₂ SiO _2/2 ] is less than 90 mol%, the viscosity of the defoaming agent becomes low, and the defoaming property becomes poor, which is not preferable, and exceeds 99.8 mol%. In such a case, the viscosity of the defoaming agent becomes high, which makes the handling difficult, which is not preferable. Furthermore, if [R ^{₁ 1} SiO _{3/2] 3/2} is lower than 0.1 mol% is made the viscosity of the defoaming agent is low, it is not preferable because depressive foaming becomes poor, more than 5 mol% In such a case, the viscosity of the defoaming agent becomes high, which makes the handling difficult, which is not preferable.

Component (I) preferably has a low viscosity from the viewpoint of dispersibility and workability, and preferably has a high viscosity from the viewpoint of foam suppression. Therefore, the viscosity of the component (I) at 25 ° C. is 100 to 1,000,000 cP (centipoise), preferably 1,000 to 100,000 cP. When the viscosity is less than 100 cP, the defoamer has poor foam suppressing properties, which is not preferable.
If it exceeds 000 cP, the operation becomes difficult when preparing an emulsion of an antifoaming agent, which is not preferable.

As the finely divided silica of the component (II), known silicas may be used, and any of wet silica and dry silica may be used. Precipitated silica, silica xerogel and fumed silica, and their surfaces are hydrophobized. What was processed is mentioned. More specifically, as commercial products, Aerosil (trade name, manufactured by Nippon Aerosil Co., Ltd.), Nibucil (trade name, manufactured by Nippon Silica Co., Ltd.),
Cabosil (trade name, manufactured by Cabonet, USA) and Santocell (trade name, manufactured by Monsanto Co., USA). The fine powdered silica has a specific surface area of 100 m
It is preferably at least ² / g, more preferably at least 200 m ² / g.

Component (I) and component (I) in component (A)
The mixing ratio with I) is 80 to 99.9: 0.1 to 20.
(% By weight), preferably 90 to 99: 1 to 10 (% by weight). When the blending ratio of the component (II) is less than 0.1% by weight, the foam suppressing property of the defoaming agent becomes poor, which is not preferable. When it exceeds 20% by weight, the viscosity of the component (A) becomes high. And handling becomes difficult, which is not preferable.

The component (A) is heat-treated, for example, at 60 to 200 ° C. while stirring the components (I) and (II) in the above mixing ratio in a mixer having a stirring mechanism. To remove low-boiling fractions. In addition, an inorganic ammonium salt, an organosilicon compound, a siloxane resin, or the like may be added to the component (A) for the purpose of improving the defoaming continuity, high-temperature properties, and dilution stability. -42043, JP-A-5-261206 and JP-A-5-2612
No. 07 gazette).

The component (B) in the antifoaming agent of the present invention is used for emulsifying and dispersing (dispersing) the above-mentioned component (A) in an aqueous system. The component (III) polyoxyalkylene-modified silicone oil And a mixture of component (IV) and a polyhydric alcohol alkyl ether.

The polyoxyalkylene-modified silicone oil of the component (III) is represented by the above structural formula (1), and is a monovalent organic compound having 1 to 20 carbon atoms represented by R ² in the structural formula (1). Examples of the group include the same as those exemplified as R ¹ of the component (I). In addition, each R ² may be the same or different, but it is preferable that 90 mol% or more of the whole is methyl.

In the definition of A in the structural formula (1), examples of the divalent hydrocarbon group having 1 to 4 carbon atoms represented by R ³ include those having 1 to 4 carbon atoms such as methylene, ethylene, propylene and butylene. Examples of the divalent hydrocarbon group include an alkyl group having 1 to 6 carbon atoms for R ⁴ , such as methyl, ethyl, propyl, butyl, pentyl and hexyl, and an acyl group for R ⁴ includes acetyl. , Propionyl, butyryl and hexanoyl and the like.

P and q in the structural formula (1) are 10
≦ p + q ≦ 100, preferably 20 ≦ p + q ≦ 70, and an integer satisfying 10: 90 ≦ p: q ≦ 100: 0, preferably 20:80 to 80:20. p + q
Is less than 10, it is not preferable because it becomes difficult to disperse the antifoaming agent in water, and when p + q exceeds 100, the viscosity increases and the workability decreases, which is not preferable. On the other hand, if p / q is less than 10/90, it is difficult to disperse component (A) in water, which is not preferable.

Further, a and b in the structural formula (1)
Is 10 ≦ a + b ≦ 1,000, preferably 50 ≦ a +
b ≦ 500, and 50: 50 ≦ a: b ≦ 99:
1, preferably an integer satisfying 80: 20 ≦ a: b ≦ 95: 5. When a + b is less than 10, the viscosity is low, and the components in the antifoaming agent are separated, resulting in low stability. If it is more than 1,000, the viscosity is high, It is not preferable because water dispersion becomes difficult and workability decreases. On the other hand, when a / b is less than 50/50 or more than 99/1, it is difficult to disperse the antifoaming agent in water, which is not preferable.

The component (III) is preferably a low-viscosity liquid from the viewpoint of dispersibility and workability, and preferably a high-viscosity one from the viewpoint of foam suppression. Therefore, 25 ° C. of component (III)
Has a viscosity of 100 to 1,000,000 cP, preferably 5,000 to 1,000,000 cP, more preferably 10,000 to 500,000 cP. If the viscosity is less than 100 cP, the components in the antifoaming agent are separated and become unstable.
If it exceeds 000 cP, the operation becomes difficult when preparing an emulsion of an antifoaming agent, which is not preferable.

The component (III) is preferably dissolved in an aqueous surfactant solution in order to enhance the dispersibility of the antifoaming agent in the aqueous foaming solution. Component (III) can be prepared by a known method, for example, (≡
It can be easily obtained by subjecting an organopolysiloxane having an Si—H) group to an addition reaction with a polyoxyalkylene compound having an unsaturated group such as vinyl or allyl at the molecular chain terminal in the presence of a platinum catalyst.

The polyhydric alcohol alkyl ether of the component (IV) has a function of an emulsifying aid. By blending this component, an appropriate fluidity is given to the component (B), and the uniformity of the defoamer composition is improved. For this purpose, component (IV) is used as a mixture with component (III).

The polyhydric alcohol alkyl ether of the component (IV) may be any one having a (R ⁵ O) group (here, R ⁵ means ethylene or propylene) in the molecule. Or a branched chain as shown by the following formula.

[0038]

Wherein R ⁶ is the same or different and is a hydrogen atom or a monovalent organic group having 1 to 6 carbon atoms;
And t are integers.) As a monovalent organic group having 1 to 6 carbon atoms represented by R ⁶ ,
The same as those exemplified as the group R ¹ of the component (I) can be mentioned. R ⁶ is preferably a hydrogen atom, or an alkyl group such as methyl, ethyl, butyl, pentyl and hexyl.

The molecular weight of the polyhydric alcohol alkyl ether of the component (IV) is 50 to 500, preferably 70 to 30.
0. When the molecular weight is less than 50, the viscosity becomes low, and the stability with time of the antifoaming agent is inferior. Therefore, when the molecular weight exceeds 500, the viscosity becomes high, and the dispersibility and workability are reduced. Not preferred.

The component (III) and the component (I) in the component (B)
The mixing ratio with V) is from 30 to 99: 1 to 70 (% by weight), preferably from 50 to 90:10 to 50 (% by weight). If the compounding ratio of the component (III) is less than 30% by weight, the water dispersibility of the defoaming agent decreases, which is not preferable.
If the content exceeds 9% by weight, the uniformity of the defoamer composition is impaired, which is not preferred.

The component (B) can be obtained by mixing the component (III) and the component (IV) in the above mixing ratio. More preferably, the component (B) is synthesized at the time of synthesis of the component (III). In the addition reaction synthesis, the component (IV) is preferably added and mixed together with the raw materials for synthesis. According to this method, the component (B) is obtained in one step.

The compounding ratio of component (A) to component (B) in the antifoaming agent of the present invention is from 58 to 90:10 to 42 (% by weight), preferably from 60 to 85:15 to 40 (% by weight). , More preferably 60 to 80: 20 to 40 (% by weight). If the compounding ratio of the component (A) is less than 58% by weight, the defoaming effect of the defoaming agent becomes insufficient, and if it exceeds 90% by weight, the water dispersibility of the defoaming agent becomes poor. It is not preferred because it lowers and makes handling difficult.
The surfactant of the component (C) in the antifoaming agent of the present invention has a function of further improving the water dispersibility of other components in the antifoaming agent.

As the surfactant of the component (C), known surfactants can be used. For example, sorbitan fatty acid esters, glycerin fatty acid esters, polyglycerin fatty acid esters, propylene glycol fatty acid esters, sucrose fatty acid esters, Oxyethylene alkyl ether, polyoxypropylene alkyl ether,
Polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyoxyethylene propylene glycol fatty acid ester, polyoxyethylene castor oil, polyoxyethylene Examples include hardened castor oil, polyoxyethylene phytostanol ether, polyoxyethylene phytosterol ether, polyoxyethylene cholesteryl ether, polyoxyethylene cholesteryl ether, alkanolamide, sugar ethers and sugar amides. Among them, those having an HLB (hydrophilic lipophilic balance) value of 1 to 10, preferably 2 to 8, and an HLB value of 1
It is preferable in terms of water dispersibility that a combination of two or more of those having 0 to 20, preferably 12 to 18 is used.

The mixing ratio of component (C) is 0.1 to 100 parts by weight based on the total amount of component (A) and component (B).
It is 50 parts by weight, preferably 1 to 10 parts by weight. If the mixing ratio of the component (C) is less than 0.1 part by weight, the effect of improving the water dispersibility is not sufficient, and if it is more than 50 parts by weight, the foam suppressing property decreases, which is not preferable. . The thickener comprising the water-soluble polymer of the component (D) in the antifoaming agent of the present invention improves the dispersibility of other components in the antifoaming agent and improves workability in preparing the antifoaming agent. Improve.

As the water-soluble polymer of the component (D), known polymers can be used, for example, xanthan gum, starch, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose salt, polyvinyl alcohol, Examples include cellulose glycol, alginate, poly (meth) acrylate, long-chain alkyl-modified poly (meth) acrylate and guar gum.

The mixing ratio of the component (D) is 0.01 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B).
10 to 10 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.1 to 2 parts by weight. When the blending ratio of the component (D) is less than 0.01% by weight, the stability of the defoaming agent becomes poor, so that it is not preferable. When it exceeds 10% by weight, the viscosity increases and the workability decreases. Is not preferred.

The antifoaming agent of the present invention can be obtained by dispersing the components (A) to (D) in water, but the preparation method is not particularly limited. For example, it can be obtained by adding a mixture of the components (A) to (C) to an aqueous solution in which the component (D) is dispersed and uniformly mixing. For this mixing, for example, a homomixer,
Universal mixer (trade name), Ultra mixer (trade name),
A mixer such as a planetary mixer (trade name) or a combination (trade name) can be used. In addition,
During this mixing, the mixture may be heated at a temperature in the range of 40-150C.

The antifoaming agent of the present invention can be applied to a pulp production process, for example, a process in which a foaming phenomenon occurs, such as a cooking process, a washing process, a bleaching process and a preparation process. Among the above pulp manufacturing processes, the washing process and the bleaching process are apt to cause a foaming phenomenon because the process water contains black liquor, and the antifoaming agent of the present invention can be suitably used in these processes.

The antifoaming agent of the present invention is used, for example, in the washing step, in a vat of a vacuum drum washer, a filtrate tank, a pipe from the vacuum drum washer to the filtrate tank, a pipe from the filtrate tank to the vacuum drum washer, a vacuum drum washer. Is added to the process water that stays or circulates in the spraying pipe and the pipe that circulates through the repulper. In the bleaching step, it is added to the process water in the vat and the filtrate tank.

Therefore, according to the present invention, there is provided a method for producing pulp, characterized by adding the above-mentioned antifoaming agent to the process water of the pulp production process.

The amount of the defoamer of the present invention is generally from 1 to 500 g / total weight of the absolutely dried pulp as a total concentration.
n, preferably 10 to 200 g / ton, but it is appropriately increased or decreased depending on the temperature and pH of the process water to be added, the type and amount of the foaming substance and the like. If the amount is less than 1 g / ton, a sufficient defoaming effect may not be obtained, which is not preferable. On the other hand, if the added amount exceeds 500 g / ton, the pulp dewatering efficiency in the subsequent step may decrease, which is not preferable.

According to the present invention, the components (A) to (D) in the above mixing ratio may be added separately, but it is convenient and preferable to add them as a one-part preparation. Further, in consideration of the dispersion efficiency of the antifoaming agent after addition, a one-part formulation may be used in which the antifoaming agent is diluted with an appropriate organic solvent or water.

The antifoaming agent of the present invention may be added continuously or intermittently, or added in conjunction with a foam measuring machine and an antifoaming agent adding device, that is, the amount to be added is determined according to the measurement result of the foam. Any of the addition methods may be used. In addition, the addition location is 1
Both points and multiple points may be used. The antifoaming agent of the present invention comprises:
Other known antifoaming agents may be used in combination as long as the purpose is not adversely affected.

[0055]

EXAMPLES The present invention will be described below with reference to Formulation Examples and Examples, but the present invention is not limited by these Formulation Examples and Examples.

Formulation Example 1 [Preparation of Component (A)]_Three)_Three SiO_1/2]:
[(CH_Three)_Two SiO_2/2]: [(CH_Three)₁ SiO_{3 / Two}] = 1.
0: 98.0: 1.0 (mol%) at 25 ° C.
Organopolysiloxane 28 having a viscosity of 8,000 cP
5 g, and (CH_Three)_ThreeSiNHSi (CH_Three)_ThreeWith surface
Fine powdered silica that has been subjected to hydrophobic treatment
Product name: Aerosil 200, manufactured by Nippon Aerosil Co., Ltd.
Specific surface area 200m^Two/ G) 15 g, and further carbonated ammonium
0.9 g of N (Kanto Chemical Co., Ltd.)
Mix at 150 ° C. for 3 hours under a gas stream and mix with component (A)
An oil compound was prepared.

[Preparation of Component (B)] The following structural formula:

[0058]

Embedded image

Wherein A ₁ is —CH ₂ CH ₂ CH ₂ O
(CH ₂ CH ₂ O) ₃₃ [CH ₂ CH (CH ₃ ) O] ₁₁ H
And the viscosity at 25 ° C. is 230,00
85 parts by weight of a polyoxyalkylene-modified silicone oil of 0 cP and 15 parts by weight of dipropylene glycol monomethyl ether were mixed to obtain 30 g of the component (B).

[Preparation of antifoaming agent 1] In a planetary mixer having a capacity of 500 ml, the component (A) 70 obtained above was added.
g, component (B) 30 g, sorbitan monostearate as component (C-1) (manufactured by NOF Corporation, HLB =
4.7) 6 g, and polyoxyethylene fatty acid ester as component (C-2) (manufactured by Kao Corporation, HLB =
19.1) 6 g was added, and the mixture was stirred at 70 to 80 ° C for 1 hour to obtain 112 g of a pale yellow-white “Composition 1” having a viscosity at 25 ° C of 100,000 cP. 500ml capacity
In a glass beaker, 30 g of the obtained composition 1 was collected,
Heated to 60 ° C. Next, 20 g of hot water at 60 ° C. was added to the composition 1, and 1,500 rpm was added using a homomixer.
Mix for 30 minutes at pm. To the mixture, 50 g of a 0.3% xanthan gum aqueous solution was added as the component (D), and the mixture was stirred to obtain an antifoaming agent 1.

Test Example 1 [Test for confirming the defoaming effect of N-material black liquor] Two liters of N-material black liquor (sample water) collected from a paper mill was adjusted to a liquid temperature of 80 ° C., and the circulation test apparatus shown in FIG. make use of,
A test for confirming the defoaming effect of the defoaming agent 1 and the comparative defoaming agent 1 as the defoaming agent of the present invention was carried out. As comparative defoamer 1,
A known mineral oil amide defoamer was used.

That is, 2 liters of the sample water (3) having a liquid temperature of 80 ° C. was charged into the container (2) of the circulation test apparatus (1), and the sample was supplied at a flow rate of 24 liters / minute using the liquid sending pump (4). Water circulated. The sample water was circulated to the container (2) via the container (2), the bottom of the container, the pipe A (5), the liquid feed pump (4), and the pipe B (6) (indicated by arrows in the figure). When foaming (7) occurred in the sample water and the foam height reached 6 cm based on the still water state, an antifoaming agent was added to a predetermined concentration, and the foam height was measured over time. . The results obtained are shown in Table 1 and FIG.

[0063]

[Table 1]

Test Example 2 [Test for confirming defoaming effect in L-material pulp production process] L-material pulp production process in a certain paper mill (average pulp production 6
(00 t / day), a test for confirming the defoaming effect of the defoaming agent 1 and the comparative defoaming agent 1 was carried out.
The same defoaming agent 1 as in Test Example 1 was used.

That is, an antifoaming agent was added to the vat inlet side, the vat outlet side, and the filtration tank in the bleaching step in the L-material pulp production step, and the defoaming effect and the effect on the product after the papermaking step were examined.

As a result, with the defoaming agent 1 of the present invention, a good defoaming effect was obtained at an addition amount of 18 g / ton (per weight of absolutely dried pulp), and did not adversely affect the product. On the other hand, in the case of the comparative antifoaming agent 1 which is a known amide-based antifoaming agent, a good antifoaming effect was obtained when the amount of the antifoaming agent 1 added was about 10 times (178 g / ton, based on the absolute dry pulp weight). ,
Pitch trouble was observed in the product after the paper making process.

[0067]

Industrial Applicability The present invention is excellent in initial foam breaking property, foam suppression persistence and emulsion stability even under severe conditions of high temperature and high alkalinity, and excellent in causing no dirt in the system and pitch trouble in the paper making process. Provide a silicone-based antifoaming agent.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a circulation test device for confirming the defoaming effect of the defoaming agent of the present invention.

FIG. 2 is a graph showing the defoaming effect of the defoaming agent of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circulation test apparatus 2 Container 3 Test water 4 Liquid sending pump 5 Pipe A 6 Pipe B 7 Foaming

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Keiji Kita 2-10-15 Higashiawaji, Higashi-Yodogawa-ku, Osaka-shi Inside Katayama Chemical Industry Research Institute (72) Inventor Yoshitaka Aoki Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture No. 1-10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Technology Laboratory F-term (reference) 4D011 CA02 4L055 AG18 AG34 AG38 AG47 AG64 AG86 AH29 AH35 AH36 EA20 EA25 EA30 EA32

Claims (4)

[Claims] (A) The following component (I) and component (I)
58-90% by weight of an oil compound consisting of (I), (I) [R¹ _ThreeSiO_1/2] [R¹ _TwoSiO_2/2] [R¹ ₁S
iO_3/2]_3/2 (Wherein each R¹Are the same or different and have 1 to 20 carbon atoms
Which is a monovalent organic group).
The composition ratio is [R¹ _ThreeSiO_1/2]: [R¹ _TwoSi
O _2/2]: [R¹ ₁SiO_3/2]_3/2= 0.1-5: 90
９９99.8: 0.1 to 5 (mol%) at 25 ° C.
Having a viscosity of 100 to 1,000,000 cP
80 to 99.9% by weight of ganopolysiloxane (II) 0.1 to 20% by weight of finely divided silica (B) Mixture of the following components (III) and (IV)
(III) the following structural formula (1):[Wherein each R^TwoAre the same or different and have 1 to 20 carbon atoms
Wherein A is -R^Three-O (CH_TwoCH_Two
O)_p[CH_TwoCH (CH_Three) O]_q-R^Four(here,
R^ThreeIs a divalent hydrocarbon group having 1 to 4 carbon atoms, R^FourIs hydrogen field
, An alkyl group having 1 to 6 carbon atoms, an acyl group or an isocyanate
An ano group, p and q are 10 ≦ p + q ≦ 100, 1
0: 90 ≦ p: q ≦ 100: 0)
And a and b are 10 ≦ a + b ≦ 1,000, 5
An integer satisfying 0: 50 ≦ a: b ≦ 99: 1, c
Is 0 or 1], and the viscosity at 25 ° C. is
Polyoxyal having 100 to 1,000,000 cP
30% to 99% by weight of a kylene-modified silicone oil (IV) Polyhydric alcohol alkyl ether having a molecular weight of 50 to 500
1-70% by weight based on 100 parts by weight of the total amount of component (A) and component (B)
Other than (C) polyoxyalkylene-modified silicone oil
0.1 to 50 parts by weight of a surfactant, and (D) 0.01 to 10 parts by weight of a thickener comprising a water-soluble polymer
Pulp making plant characterized by dispersing an amount of water in water
Defoaming agent. 2. A method for producing pulp, comprising adding the antifoaming agent according to claim 1 to process water in a pulp production process. 3. The method according to claim 2, wherein the defoaming agent is added so as to have a total concentration of 1 to 500 g / ton per absolute dry pulp weight. 4. The production method according to claim 2, wherein the pulp production step is a washing step and / or a bleaching step.