JP6201129B2 - Low foaming antifouling agent and antifouling method for paper and pulp manufacturing process - Google Patents

Description

  The present invention relates to a low-foaming antifouling agent used in a paper / pulp production process and a antifouling method using the same. More particularly, the present invention relates to a low-foaming antifouling agent for preventing fouling of a wire part, a press part roll, a blanket, a blanket suction box and the like in a paper / pulp manufacturing process and a fouling prevention method using the same.

  In the paper / pulp manufacturing process, various stains derived from papermaking raw materials and paper additives adhere to manufacturing equipment and paper in the middle of manufacturing, resulting in decreased productivity and workability due to paper product quality degradation and paper breakage. Various failures occur. For example, in wire part, press part rolls, blankets and blanket suction boxes, inorganic acids such as aluminum hydroxide and calcium carbonate, filler ingredients such as kaolin, clay, talc and titanium oxide, resins derived from pulp raw materials and waste paper raw materials Acids, fatty acids, latex, ink particles, and the like, sizing agents derived from papermaking additives, yield improvers, paper strength enhancers, and the like are attached.

  In conventional paper manufacturing, mechanical pulp (MP) such as ground wood pulp (GP) and thermomechanical pulp (TMP) is mainly used as a raw material, and waste paper is partially used. Therefore, it is a water-insoluble adhesive substance mainly composed of organic substances derived from wood, pulp and paper, natural resins and gum substances liberated from them, and additives used in the manufacturing process of paper and pulp. The so-called pitch was the main obstacle.

  However, in recent years, the ratio of recycled paper used as a raw material has increased from the viewpoint of recycling, and not only the conventional pitch, but also the obstacles due to pitch such as latex derived from waste paper and vinyl acetate adhesive (hot melt) have increased. Yes. In addition, the production of neutral paper has become the mainstream, and composite stains including inorganic substances such as filler components such as calcium carbonate are also increasing. On the other hand, the speed of papermaking to improve paper productivity has led to the problem of pitch contamination on the wire part, press part roll, blanket, and blanket suction box, combined with an increase in the ratio of used paper and an increase in the size of the papermaking machine. It has become apparent.

Conventionally, antifouling agents mainly composed of various surfactants have been used for pitch stains mainly composed of organic substances. In recent years, antifouling agents using low foaming surfactants have been proposed. For example, the following techniques are disclosed.
JP-A-2003-328296 (Patent Document 1) discloses a pitch control agent comprising an aqueous solution containing a polyether derivative such as polyethyleneimine polyoxyethyleneoxypropylene and a nonionic or cationic surfactant. .
JP-A-2005-226180 (Patent Document 2) discloses a stain accumulation preventing composition in a paper machine containing a nonionic surfactant and a carboxylic acid (salt) in a specific ratio.

JP 2008-115500 A (Patent Document 3) contains a salt of an addition condensate of an alkylene polyamine and an acrylic acid derivative, a polyoxyalkylene alkyl ether, and a polyoxyethylene polyoxypropylene glycol in a specific ratio. Pitch adhesion inhibitors are disclosed.
Japanese Patent Application Laid-Open No. 2010-163700 (Patent Document 4) discloses an antifouling agent composition containing a nonionic surfactant and a hydroxycarboxylic acid (salt) in a specific ratio.
JP 2013-28887 A (Patent Document 5) discloses a pitch suppression method in which a surfactant such as polyoxyethylene polyoxypropylene alkyl ether is added together with a chelating agent.

  Further, the applicant of the present application is for a paper / pulp manufacturing process containing a cationic polymer such as polydiallyldimethylammonium salt and a nonionic surfactant obtained by adding ethylene oxide or ethylene oxide and propylene oxide to a higher aliphatic amine. A pitch inhibitor was proposed (Patent Document 6).

JP 2003-328296 A JP 2005-226180 A JP 2008-115500 A JP 2010-163700 A JP 2013-28887 A JP 2004-44067 A JP 2005-187980 A Japanese National Patent Publication No. 11-505299 JP-T-2002-521588 JP 2008-240227 A

However, even if it has low foaming properties, for example, when the above-mentioned surfactant is added to the top roll shower water in the press part of a paper machine, the shower water foams in the top roll liquid pool and foams. The foamed liquid causes unevenness of the paper. Also, if the foaming is too high, the paper machine operation must be stopped. Such bubbles were troublesome bubbles that could not be sufficiently prevented even when an antifoaming agent was added.
Accordingly, the present invention provides a low-foaming antifouling agent that exhibits an effective antifouling effect without using a surfactant and does not impede papermaking (papermaking) by foaming, and antifouling using the same It is an object to provide a method.

  In order to solve the above problems, the inventors have assumed that surfactants that have been conventionally considered necessary for preventing organic stains in the paper / pulp manufacturing process are not used, and the stain-preventing effect of various chemicals. As a result of extensive research on the above, the inventors have surprisingly found that the combination of the following specific compounds has low foaming properties and exhibits a remarkable antifouling effect, and has completed the present invention.

  Thus, according to the present invention, (A) a dimethyl ester or diethyl ester or benzyl alcohol of a dicarboxylic acid having an alkylene group having 2 to 4 carbon atoms, (B) a glycol compound, and (C) an organic phosphonic acid, an organic carboxylic acid Provided is a low-foaming antifouling agent for a paper / pulp production process, which comprises an acid, an organic sulfonic acid, an inorganic acid or a salt thereof.

  Further, according to the present invention, (A) a dimethyl ester or diethyl ester or benzyl alcohol of a dicarboxylic acid having an alkylene group having 2 to 4 carbon atoms, in a paper / pulp production process water system or a papermaking process or a shower water system in a dehydration process, (B) Glycol-based compound and (C) organic phosphonic acid, organic carboxylic acid, organic sulfonic acid, inorganic acid or salt thereof, simultaneously or separately, as active ingredient (A) + (B) + (C) 5 A method for preventing soiling in a paper / pulp production process is provided, which is added so as to be ˜2000 mg / L.

According to the present invention, there is provided a low-foaming antifouling agent that exhibits an effective antifouling effect without using a surfactant and that does not impair the papermaking due to foaming, and a antifouling method using the same. can do.
Further, the low-foaming antifouling agent of the present invention is particularly useful for preventing composite fouling composed of organic substances such as pitch components and inorganic substances such as calcium carbonate.
The low-foaming antifouling agent of the present invention can remarkably prevent soiling of wire parts, press part rolls, blankets and blanket suction boxes in the paper / pulp manufacturing process, and in particular, press part parts of paper machines. In the top roll, the papermaking machine is not adversely affected by foaming, and the paper machine can be remarkably prevented from being soiled.

The dicarboxylic acid diester (diisobutyl adipate) of the component (A) of the present invention is known as a paper machine cleaning agent in combination with alkylbenzyldimethylammonium chloride, polyoxyethylene alkylamine, etc. -187980 gazette: refer patent document 7).
Moreover, it is known that the other (A) component benzyl alcohol dissolves pitch (for example, refer to Japanese Patent Publication No. 11-505299: Patent Document 8).

  The glycol ethers of component (B) of the present invention should be used together with peracetic acid and cleaning compounds (organic acids and mineral acids) as cleaning solutions to remove and prevent the accumulation of contaminants in wet press felt for papermaking and forming wires. Is known (for example, see Japanese Translation of PCT International Publication No. 2002-521588: Patent Document 9).

The organic phosphonic acid of the component (C) of the present invention is known to be used as a stain cleaning agent containing a pitch of a papermaking process together with a polyether compound derivative, a nonionic surfactant and a cationic surfactant ( For example, see Patent Document 1).
Further, the organic carboxylic acid of component (C) of the present invention is known as one component of a soil accumulation preventing composition in a paper machine used in combination with a nonionic surfactant (see, for example, Patent Document 2).
Further, it is known that the acid of the component (C) of the present invention is used as a paper machine soil adhesion preventive composition together with a polyether ester amide and a cationic surfactant (for example, Japanese Patent Application Laid-Open No. 2008-240227). Publication: Refer to Patent Document 10).

  However, in the above prior art, there is no description or suggestion that the three components of the low-foaming antifouling agent for the paper / pulp production process of the present invention are used together, and the combination of these three components is not used. It is an unexpected synergistic effect that even those skilled in the art cannot expect, and that such effects are also described in the above prior art. There is no suggestion.

Moreover, the low foaming antifouling agent for paper / pulp production process of the present invention is any one of the following requirements:
(1) The low foaming antifouling agent is an aqueous composition obtained by dissolving the component (A), the component (B) and the component (C) in water.
(2) The blending ratio of the component (A) in the aqueous composition is 0.5 to 60% by weight of the composition, the blending ratio of the component (B) is 1 to 90% by weight of the composition, (C) the blending ratio of the component is 1 to 50% by weight of the composition, and (3) the component (A) is dimethyl succinate, dimethyl glutarate, dimethyl adipate or benzyl alcohol, (B) The component is dipropylene glycol or diethylene glycol monobutyl ether, and the component (C) is 1-hydroxyethane-1,1-diphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, malic acid, methanesulfone When the acid, sulfamic acid or salt thereof is satisfied, the above effect is further exhibited.

It is the schematic of the testing apparatus used for the foaming property test of the low foaming antifouling agent for the paper and pulp manufacturing processes of this invention. It is the schematic of the testing apparatus used for the antifouling property test of the low foaming antifouling agent for paper and pulp manufacturing processes of this invention.

The low-foaming antifouling agent (hereinafter also referred to as “antifouling agent”) for the paper / pulp production process of the present invention is (A) a dimethyl ester or diethyl ester of a dicarboxylic acid having an alkylene group having 2 to 4 carbon atoms. Alternatively, benzyl alcohol, (B) a glycol compound, and (C) an organic phosphonic acid, an organic carboxylic acid, an organic sulfonic acid, an inorganic acid or a salt thereof are characterized.
Each active ingredient of the antifouling agent of the present invention is a known compound, and commercially available products can be used.

The component (A) of the present invention is a dimethyl ester or diethyl ester of dicarboxylic acid having an alkylene group having 2 to 4 carbon atoms or benzyl alcohol (BA).
Examples of the dimethyl ester or diethyl ester of a dicarboxylic acid having an alkylene group having 2 to 4 carbon atoms include dimethyl succinate, dimethyl glutarate, dimethyl adipate (DA), diethyl succinate, diethyl glutarate and diethyl adipate. In the present invention, one of these may be used alone or in combination of two or more.

Among these, at least one selected from dimethyl succinate, dimethyl glutarate and dimethyl adipate is preferable from the viewpoint that a more remarkable antifouling effect is exhibited when used in combination with component (B) and component (C), Further, from the economical aspect, a mixture of three kinds of dimethyl succinate, dimethyl glutarate and dimethyl adipate is particularly preferred.
This mixture of three kinds of dimethyl esters of dicarboxylic acid is industrially said to be a by-product in the process of polymer production. For example, a product name “DBE” from DuPont INVISTA is used for a solvent or the like. (Registered trademark) ”.
Benzyl alcohol is also a preferred component (A).

The component (B) of the present invention is a glycol compound.
Examples of the glycol compound include glycols such as ethylene glycol, propylene glycol, diethylene glycol and dipropylene glycol (DPG); ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether, ethylene glycol Examples include glycol ethers such as monohexyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether (BDG), propoxypropanol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and tripropylene glycol methyl ether. Alone or two It can be used in combination on.
Among these, dipropylene glycol and diethylene glycol monobutyl ether are preferable, and a combination of these is particularly preferable because a more remarkable antifouling effect is exhibited when used in combination with the components (A) and (C).

  Component (C) of the present invention is an organic phosphonic acid, organic carboxylic acid, organic sulfonic acid, inorganic acid or salt thereof. Examples of such salts include alkali metal salts such as sodium salts and potassium salts, and ammonium salts. In this invention, these 1 type can be used individually or in combination of 2 or more types.

Examples of the organic phosphonic acid include 1-hydroxyethane-1,1-diphosphonic acid (also known as: 1-hydroxyethylidene-1,1-diphosphonic acid: HEDP), 2-phosphonobutane-1,2,4-tricarboxylic acid ( PBTC), aminotrimethylenephosphonic acid, hexamethylenediaminetetra (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid) and diethylenetriaminepenta (methylenephosphonic acid). A combination of more than one species can be used.
Among these, 1-hydroxyethane-1,1-diphosphonic acid and 2-phosphonobutane-1,2,4 are more prominent due to the combined use of the component (A) and the component (B). -Tricarboxylic acids are preferred.

Examples of the organic carboxylic acid include oxalic acid, malonic acid, succinic acid, maleic acid, itaconic acid, malic acid (MA), tartaric acid, citric acid and lactic acid. In the present invention, one of these may be used alone or Two or more kinds can be used in combination.
Among these, malic acid is preferable because a more remarkable antifouling effect is exhibited when used in combination with the components (A) and (B).

Examples of the organic sulfonic acid include benzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid (MSA), and ethanesulfonic acid. In the present invention, one of these is used alone or two or more are used in combination. be able to.
Among these, methanesulfonic acid is preferable from the viewpoint that a more remarkable antifouling effect is exhibited when used in combination with the components (A) and (B).
Examples of inorganic acids include sulfamic acid (SA).

The antifouling agent of the present invention is an aqueous solution obtained by dissolving the component (A), the component (B), and the component (C) in water from the viewpoints of safety, storage, transportation, handling (workability), economy, and the like. Preferably it is a composition.
The aqueous composition of the antifouling agent of the present invention can be prepared, for example, by adding each component to water and mixing them.

In the antifouling agent of the present invention, the blending ratio of the component (A) in the aqueous composition is 0.5 to 60% by weight of the composition, and the blending ratio of the component (B) is 1 to 1 of the composition. 90% by weight and the blending ratio of component (C) is 1 to 50% by weight of the composition, a uniform aqueous composition can be obtained, and a more pronounced synergistic antifouling effect can be achieved. This is preferable.
Furthermore, the blending ratio of the component (A) in the aqueous composition is 1 to 60% by weight of the composition, the blending ratio of the component (B) is 5 to 80% by weight of the composition, It is particularly preferable that the blending ratio of component C) is 2 to 30% by weight of the composition.

  In the antifouling agent of the present invention, the content ratio of the active ingredient in the aqueous composition is not particularly limited, but is usually 1 to 95 parts by weight, preferably 5 to 95 parts by weight as the total amount of active ingredients in 100 parts by weight of the preparation. Parts, more preferably 10 to 95 parts by weight.

  The antifouling agent of the present invention is, for example, by adding the above aqueous composition to a paper / pulp production process water system or a shower water system of a paper making process or a dehydration process, thereby providing equipment for those process water systems, particularly a wire part and a press part. It is possible to remarkably prevent the rolls, blankets, and blanket suction boxes from becoming dirty.

The antifouling agent of the present invention may contain other additives known in the art as long as the effects of the present invention are not impaired.
For example, polydiallyldimethylammonium chloride (DADMAC) can improve the antifouling effect.
Moreover, polyoxyethylene distyrenated phenyl ether phosphate diethanolamine (PA) can improve the formulation stability of the aqueous composition.

The method for preventing soiling in the paper / pulp production process of the present invention comprises: (A) a dimethyl ester of a dicarboxylic acid having an alkylene group having 2 to 4 carbon atoms in a paper / pulp production process water system or a papermaking process or a shower water system in a dehydration process; Diethyl ester or benzyl alcohol, (B) glycol compound, and (C) organic phosphonic acid, organic carboxylic acid, organic sulfonic acid, inorganic acid or salt thereof, simultaneously or separately, active ingredient (A) + (B) + (C) is added so as to be 5 to 2000 mg / L.
The details of the preferred compounds (A) to (C) used in the stain prevention method of the present invention, the combined use ratio, and the like are the same as those of the stain preventive agent of the present invention.

  The amount of paper / pulp manufacturing process water or dewatering process added to the shower water may be set as appropriate depending on the amount of soil components present, but usually, as an active ingredient in the process water or shower water, By continuously or intermittently adding so as to be 2000 mg / L, preferably 10 to 500 mg / L, it is possible to remarkably prevent dirt adhering to the equipment.

  The present invention will be specifically described with reference to the following examples and comparative examples, but the present invention is not limited thereto.

Example 1
[Anti-fouling agent]
(A) As a dimethyl ester of a dicarboxylic acid having an alkylene group having 2 to 4 carbon atoms as a component, a mixture of dimethyl adipate, dimethyl glutarate and dimethyl succinate (trade name: DBE (registered trademark) manufactured by INVISTA) 2 1% by weight, 15% by weight of diethylene glycol monobutyl ether and 6% by weight of dipropylene glycol as the glycol compound of component (B), 1-hydroxyethane-1,1-diphosphonic acid as the organic carboxylic acid of the acid of component (C) The antifouling agent of Example 1 (about 500 mL) was obtained by adding 5% by weight and 72% by weight of water and mixing and stirring.
Table 1 shows each component and the blending amount thereof.

[Foamability test]
Using the test apparatus of FIG. 1, a foaming property test of the antifouling agent was performed.
Specifically, a cylindrical container 2 made of polyvinyl chloride (externally provided with a pipe heater 3 (manufactured by Yoko Electric Manufacturing Co., Ltd., voltage 100 V, power consumption 500 W)) and a tripod sunoko 4 (outer diameter 12 cm, height 7 cm) (14.7 cm in diameter, 13.9 cm in inner diameter, 30 cm in height) The test solution 1 in which the antifouling agent of Example 1 was added in advance at a concentration of 50 mg / L to 2 liters of tap water as the test water was gently added. The pipe heater 3 was heated so that the water temperature of the test solution 1 was 30 ° C.
Next, the pump 5 (manufactured by Iwaki Co., Ltd., magnet pump, model: MD-30R-N) prepared in advance so that the circulating fluid amount becomes a circulating amount of 24 L / min is operated, and from the bottom of the container 2 The test liquid 1 was sucked up, dropped from a position 7 cm above the reference liquid level through the pipe 6 (inner diameter 10 mm, path length about 100 cm), and circulated (indicated by arrows in FIG. 1).

Test solution 1 circulation start was set to 0 seconds, and the foaming height of test solution 1 foamed 10 seconds, 30 seconds, 60 seconds and 300 seconds later (the height from the reference liquid surface to the top of the foamed product) Was measured over time.
The foaming height generated in the top roll puddle in the press part of the paper machine, which is acceptable in papermaking (papermaking), is determined according to the results of a comparative evaluation with the actual machine in the above test. It corresponds to 3 cm or less in height.
Therefore, the case where the foaming height after 300 seconds was 3 cm or less was evaluated as good “◯”, and the case where it exceeded 3 cm was evaluated as defective “X”.
In the test, the foaming height reached 3 cm after 30 seconds, and the height was maintained until after 300 seconds. However, the foaming height was acceptable, and was evaluated as “good” according to the above criteria. It was.
The obtained results are shown in Table 3.

[Stain prevention test]
The antifouling property test of the antifouling agent was performed using the test apparatus of FIG.
Specifically, 1.2 liters of pure water, 3 g of calcium carbonate (special grade reagent, manufactured by Kishida Chemical Co., Ltd.) as an inorganic substance of the soil component, and ethylene vinyl acetate copolymer resin (Showa Denko Co., Ltd.) as the non-volatile component of the organic material of the soil component 3 g) was added and mixed to make the soil water sample water, and then the antifouling agent of Example 1 was added at concentrations of 100 mg / L and 200 mg / L, respectively.
Next, test water 9 is put into a beaker 8 made of polypropylene having a capacity of 1400 mL, and is left on the stirrer 10 through a warm bath 12 having a set temperature of 40 ° C., and the test water 9 is stirred by the stirrer 10 (in FIG. Felt 11 is installed on top of it, which can be rotated by motor 7 (upper arrow in FIG. 2).
The felt 11 used was a felt pipe (material: polyester, thickness 5 mm) used for a press part of a paper machine around a polystyrene pipe having an outer diameter of 150 mm and a length of 60 mm.
Prior to the test, the weight Wb (g) of the felt 11 was measured.

Next, the felt 11 was immersed in test water while being rotated at a rotation speed of 20 rpm, and held for 120 minutes.
After the test, the felt 11 was dried and the weight Wa (g) was measured.
Moreover, it tested similarly to the above except not adding an antifouling agent, and measured weight Wp (g) of the felt 11 after drying (blank).
The antifouling property (%) was determined from the obtained measured value and the following formula.
Antifouling property (%) = (Wp−Wa) / Wp × 100
The anti-smudge property in the press part of the paper machine, which is acceptable in paper making (paper making), corresponds to the anti-smudge property of 60% or more in the above test, based on a comparative evaluation of the actual machine by the inventors.
Therefore, the case where the antifouling property was 60% or more was evaluated as “good”, and the case where it was less than 60% was evaluated as “bad”.
In the test, the antifouling property was 68%, and it was found that the antifouling agent of Example 1 exhibited a sufficient antifouling effect.
The obtained results are shown in Table 3.

(Examples 2 to 23)
The antifouling agents of Examples 2 to 23 were prepared with the components (A), (B) and (C) and their blending amounts shown in Table 1, and the foaming test and soiling were conducted in the same manner as in Example 1. A preventive test was performed.
The obtained results are shown in Table 3.
In the test, in all antifouling agents, the foaming height after 300 seconds is 3 cm or less, the foaming height is acceptable, and the antifouling property is 60% or more, so that sufficient antifouling is achieved. It turned out to be effective.

(Comparative Examples 1-12)
The antifouling agents of Examples 1 to 12 were prepared with the components (A), (B) and (C) and their blending amounts shown in Table 2, and the foaming test and soiling were conducted in the same manner as in Example 1. A preventive test was performed.
The obtained results are shown in Table 3.
In Comparative Examples 1 to 7 and 9 to 12, since the antifouling property did not show 60% or more even at the addition concentration of the antifouling agent of 200 mg / L, the effect of 100 mg / L was not confirmed, and 200 mg / L The data were compared.

In the foaming test, in the antifouling agents of Comparative Examples 1 to 7 and 9 to 12 other than Comparative Example 8, the foaming height after 300 seconds is 3 cm or less, and the foaming height is acceptable. I understood. On the other hand, in the antifouling property test, the antifouling agent of Comparative Example 8 has an antifouling property of 82% and exhibits a sufficient antifouling effect. However, in the antifouling agents of Comparative Examples 1-7 and 9-12, It was found that a sufficient anti-staining effect could not be obtained.
That is, it can be seen that Comparative Examples 1 to 12 which do not have the constituent requirements of the antifouling agent of the present invention do not have both low foaming properties and antifouling properties.

In Table 1 and 2, the compound contained in each formulation is shown by the following abbreviations.
(A) Component DBE: Mixture of dimethyl adipate, dimethyl glutarate and dimethyl succinate
(Product name: DBE (registered trademark), manufactured by INVISTA)
DA: Dimethyl adipate BA: Benzyl alcohol (B) component BDG: Diethylene glycol monobutyl ether DPG: Dipropylene glycol

Component (C) HEDP: 1-hydroxyethane-1,1-diphosphonic acid SA: sulfamic acid MSA: methanesulfonic acid MA: malic acid PBTC: 2-phosphonobutane-1,2,4-tricarboxylic acid

(Additional ingredients)
PA: polyoxyethylene distyrenated phenyl ether diethanolamine (trade name: Agrisol KP-1436, manufactured by Kao Corporation)
DADMAC: polydiallyldimethylammonium chloride (average molecular weight about 50,000)
(Known antifouling ingredients)
RN (EO) 2n: Stearylamine ethylene oxide 20 mol adduct

DESCRIPTION OF SYMBOLS 1, 9 Test liquid 2 Container 3 Pipe heater 4 Tripod sunoko 5 Pump 6 Pipe 7 Motor 8 Beaker 10 Stirrer 11 Felt 12 Warm bath

Claims (5)

  (A) Dicarboxylic acid dimethyl ester or diethyl ester or benzyl alcohol having an alkylene group having 2 to 4 carbon atoms, (B) glycol-based compound, and (C) organic phosphonic acid, organic carboxylic acid, organic sulfonic acid, inorganic acid Or the low foaming antifouling agent for paper and pulp manufacturing processes characterized by containing the salt.   The low-foaming antifouling agent according to claim 1, wherein the low-foaming antifouling agent is an aqueous composition obtained by dissolving the components (A), (B) and (C) in water. .   The blending ratio of the component (A) in the aqueous composition is 0.5 to 60% by weight of the composition, the blending ratio of the component (B) is 1 to 90% by weight of the composition, The low-foaming antifouling agent according to claim 2, wherein the blending ratio of the component (C) is 1 to 50% by weight of the composition. The component (A) is dimethyl succinate, dimethyl glutarate, dimethyl adipate or benzyl alcohol;
The component (B) is dipropylene glycol or diethylene glycol monobutyl ether, and the component (C) is 1-hydroxyethane-1,1-diphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, The low-foaming antifouling agent according to any one of claims 1 to 3, which is malic acid, methanesulfonic acid, sulfamic acid or a salt thereof.   (A) a dimethyl ester or diethyl ester or benzyl alcohol of a dicarboxylic acid having an alkylene group having 2 to 4 carbon atoms, (B) a glycol compound, and a paper / pulp manufacturing process water system or a papermaking process or a dewatering shower water system (C) An organic phosphonic acid, an organic carboxylic acid, an organic sulfonic acid, an inorganic acid or a salt thereof is simultaneously or separately so that the active ingredient (A) + (B) + (C) is 5 to 2000 mg / L. A method for preventing soiling in a paper / pulp manufacturing process, characterized by comprising adding.

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