JP4254565B2 - Dirty accumulation preventing composition in paper machine, dirt accumulation preventing method and dirt removing method - Google Patents

Description

  The present invention relates to a stain accumulation preventing composition, a stain accumulation preventing method, and a stain removing method in a paper machine. More specifically, the present invention relates to a stain accumulation inhibitor composition, a stain accumulation preventing method, and a method for preventing the accumulation of dirt in a paper machine for preventing dirt accumulated on a wire of a paper machine wire part, felt in a pressing process, various rolls, and the like. The present invention relates to a method for removing dirt in a paper machine for removing dirt.

In the paper machine, the press part is in the middle of the wire part and the dryer part, and presses and squeezes the wet paper formed by the wire part to reduce the moisture in the wet paper and reduce the load on the dryer part. I'm in charge. Therefore, the water extraction efficiency in the press part is only slightly worsened, which not only increases the amount of steam required to dry the wet paper and increases the production cost, but also reduces the paper making speed to match the drying capacity. As a result, production efficiency is directly degraded. The biggest cause of poor water squeezability in the press part is felt stains, but if the felt stains are severe, the stain components may be transferred to the paper product, causing spotted defects, and It can also be a cause. Further, if the method of frequently washing and removing the attached dirt or replacing the felt is used, the operation of the paper machine is frequently stopped, which leads to a problem that the production efficiency is extremely lowered. Various kinds of obstacles are caused by the same dirt on various rolls and wires. The following description will focus on felt.
Various stains derived from papermaking raw materials and papermaking additives adhere to the felt. For example, aluminum hydroxide, inorganic salts such as calcium carbonate, filler components such as kaolin, clay, talc and titanium oxide, resin acids derived from pulp materials and waste paper materials, back glue, fatty acids derived from DIP (deinked pulp) Latex, ink particles, etc., sizing agents that are derived from papermaking additives and do not fix to pulp fibers, yield improvers, paper strength enhancers, and the like adhere. In particular, the ratio of waste paper and DIP to pulp raw materials has recently increased, and the use of a neutral sizing agent associated with the neutralization of papermaking conditions tends to increase felt stains and complicate soil components. Tend.
In the conventional papermaking method, which has been the mainstream, a rosin sizing agent is used, and aluminum sulfate is used for fixing. In such a papermaking system, aluminum hydroxide and a pitch component derived from a pulp raw material often adhere to the felt. Under such circumstances, as a cleaning agent for preventing soiling of aluminum hydroxide and calcium carbonate that accumulates in papermaking felt and lowers its performance, citric acid, malic acid chelating organic acid single solution or hydrochloric acid In addition, a paper sheet felt cleaning agent comprising a mixed solution to which an inorganic acid such as sulfuric acid or sulfamic acid is added has been proposed (Patent Document 1). Also contains a polyoxyalkylene ether solvent and an alkylpolyoxyethylene phosphate ester surfactant as a felt cleaner for papermaking that cleans paper felt, maintains uniform water squeezing, and extends felt life. A cleaning agent has been proposed (Patent Document 2).
In recent years, neutral papermaking has been widely performed, and a composition in which a chelating agent is blended with a nonionic surfactant has been partially used. For example, as a cleaning method for clarifying papermaking felt in the neutral paper manufacturing process and maintaining uniform squeezability, the felt is washed with an aminopolyacetic acid such as ethylenediaminetetraacetic acid or a salt thereof and a surfactant. A cleaning method has been proposed (Patent Document 3). However, even if these cleaning agents are used, the cleaning effect is not always sufficient, and in particular, there is a demand for a soil accumulation preventing agent for a papermaking process that is effective against stains in which causative substances are combined.
Conventionally, surfactants are effective for organic soils such as pitch, and carboxylic acids and chelating agents are considered effective for inorganic soils such as aluminum and calcium. Antifouling agents mainly composed of various surfactants are used for soils with a large amount of dirt, and antifouling agents mainly composed of organic acids and chelating agents have been used for soils with a high inorganic content. It was. However, in actual stains, organic impurities of various origins form complex complexes with metal ions such as aluminum and calcium, and surfactants alone or organic acids alone can prevent these stains. It was difficult.
JP-A-4-348195 (2nd page) JP 58-91886 A (first page) JP 11-181691 A (second page)

  The present invention relates to a soil accumulation preventive composition, a soil accumulation preventing method, and a soil accumulation preventing method in a paper machine that can effectively prevent dirt accumulated on a wire of a paper machine wire part, felt in a pressing process, various rolls, and the like. The object of the present invention is to provide a method for removing dirt on a paper machine that removes attached dirt.

As a result of intensive studies to solve the above problems, the present inventor has obtained a nonionic surfactant comprising an ethylene oxide-propylene oxide block copolymer and a polyoxyethylene alkylamine or a polyoxyethylene alkyleneamine, By using a polyvalent carboxylic acid or an alkali metal salt thereof together, it is possible to effectively prevent the accumulation of complicated stains in a paper machine, and further, the removal effect can be expressed even for stains that have already adhered. As a result, the present invention has been completed based on this finding.
That is, the present invention
(1) A stain accumulation preventing composition for a paper machine comprising a nonionic surfactant and a carboxylic acid or an alkali metal salt thereof in a weight ratio of 1: 9 to 9: 1, wherein the nonionic An ethylene oxide-propylene oxide block copolymer having a structure represented by the general formula [1] or the general formula [2] and a polyoxyethylene alkylamine having a structure represented by the general formula [3] A soil accumulation preventive composition in a paper machine, comprising polyoxyethylene alkylene amine,
_{HO- (C 2 H 4 O)} a - (C 3 H 6 O) b - (C 2 H 4 O) c H ... [1]
(However, in the formula, a + c is 10 to 40, a and c are not 0, and b is 15 to 45.)
_{HO- (C 3 H 6 O)} d - (C 2 H 4 O) e - (C 3 H 6 O) f H ... [2]
(However, in the formula, d + f is 10 to 45, d and f are not 0, and e is 10 to 40.)
R—NH— (C ₂ H ₄ O) _g H [3]
(In the formula, R is an alkyl or alkenyl group having 12 to 22 carbon atoms, and g is 5 to 30).
( 2 ) The stain accumulation preventing composition in a paper machine according to (1), wherein the carboxylic acid is a water-soluble polyvalent carboxylic acid,
( 3 ) The soil accumulation preventing composition in a paper machine according to ( 2 ), wherein the water-soluble polyvalent carboxylic acid is citric acid, malic acid, maleic acid or tartaric acid,
( 4 ) The soil accumulation inhibitor composition for a paper machine according to any one of (1) to ( 3 ) is added to a shower water system of the paper machine at a concentration of 1 to 5,000 mg / L. Method for preventing accumulation of dirt in a paper machine, and
( 5 ) The soil accumulation preventive composition in a paper machine according to any one of (1) to ( 3 ) is added to a shower water system of a paper machine to which dirt is attached, and the concentration of the composition is 500 to 100,000 mg. A soil removal method in a paper machine, characterized by being added so as to be / L,
Is to provide.

  According to the stain accumulation inhibitor composition and the stain accumulation prevention method of the paper machine of the present invention, even in a papermaking system in which complicated stains are likely to occur, the accumulation of stains is effectively prevented, and high quality products are stabilized. Paper. Furthermore, according to the dirt removal method in the paper machine of the present invention, the dirt of the paper machine that has already adhered can be removed.

The soil accumulation inhibitor composition in the paper machine of the present invention contains a nonionic surfactant and a carboxylic acid or an alkali metal salt thereof in a weight ratio of 1: 9 to 9: 1. In the method for preventing soil accumulation in the paper machine of the present invention, a nonionic surfactant and a carboxylic acid or an alkali metal salt thereof are added at a weight ratio of 1: 9 to 9: 1 in the shower water system of the paper machine. To do. In the method for removing dirt in the paper machine of the present invention, a nonionic surfactant and a carboxylic acid or an alkali metal salt thereof in a weight ratio of 1: 9 to 9: They are added at a rate of 1 so that their total concentration is 500 to 100,000 mg / L.
In the present invention, the ratio of the nonionic surfactant to the carboxylic acid or the alkali metal salt thereof is 1: 9 to 9: 1 by weight, more preferably 2: 8 to 8: 2. The ratio of the nonionic surfactant to the carboxylic acid or the alkali metal salt thereof can be appropriately selected according to the nature of the generated stain component. If the ratio of the nonionic surfactant to the carboxylic acid or its alkali metal salt is less than 1: 9 and the ratio of the nonionic surfactant is small, the effect of preventing the accumulation of organic soils becomes insufficient. There is a fear. If the ratio of the nonionic surfactant and the carboxylic acid or its alkali metal salt exceeds less than 9: 1 and the ratio of the carboxylic acid or its alkali metal salt is small, the accumulation prevention effect of inorganic soil is insufficient. There is a risk.

In the present invention, the nonionic surfactant includes an ethylene oxide-propylene oxide block copolymer having a structure represented by the general formula [1] or [2] and a structure represented by the general formula [3]. It is preferable to consist of polyoxyethylene alkylamine or polyoxyethylene alkyleneamine having
_{HO- (C 2 H 4 O)} a - (C 3 H 6 O) b - (C 2 H 4 O) c H ... [1]
_{HO- (C 3 H 6 O)} d - (C 2 H 4 O) e - (C 3 H 6 O) f H ... [2]
R—NH— (C ₂ H ₄ O) _g H [3]
However, in general formula [1], a + c is 10-40, a and c are not 0, and b is 15-45. In the general formula [2], d + f is 10 to 45, d and f are not 0, and e is 10 to 40. In General formula [3], R is a C12-C22 alkyl group or alkenyl group, and g is 5-30.
The ethylene oxide-propylene oxide block copolymer having the structure represented by the general formula [1] can be obtained by addition reaction of ethylene oxide to polypropylene oxide having hydroxyl groups at both ends. An ethylene oxide-propylene oxide block copolymer having a structure represented by the general formula [1] is a commercially available product, for example, Pluronic PE series sold as a low-foaming nonionic surfactant from BASF Japan Ltd. Etc. can also be used.

The ethylene oxide-propylene oxide block copolymer having the structure represented by the general formula [2] can be obtained by addition reaction of propylene oxide to polyethylene oxide having hydroxyl groups at both ends. The ethylene oxide-propylene oxide block copolymers having the structure represented by the general formula [2] are commercially available products such as Pluronic RPE series sold as a low foaming nonionic surfactant from BASF Japan Ltd. Etc. can also be used.
The polyoxyethylene alkylamine or polyoxyethylene alkyleneamine having the structure represented by the general formula [3] can be obtained by addition reaction of ethylene oxide with alkylamine or alkyleneamine.
In the present invention, an ethylene oxide-propylene oxide block copolymer having a structure represented by the general formula [1] or the general formula [2] and a polyoxyethylene alkylamine or poly having a structure represented by the general formula [3] There is no restriction | limiting in particular in the ratio with an oxyethylene alkylene amine, Although it can select suitably according to the property of the stain | pollution | contamination component to generate | occur | produce, Usually, it is preferable that it is 2: 8-8: 2 by weight ratio.

In the present invention, a water-soluble polyvalent carboxylic acid can be suitably used as the carboxylic acid. In the present invention, the water-soluble carboxylic acid means a carboxylic acid capable of forming an aqueous solution having a concentration of 5% by weight or more at 25 ° C. Examples of the water-soluble polyvalent carboxylic acid include saturated divalent carboxylic acids such as oxalic acid, malonic acid, and succinic acid, unsaturated divalent carboxylic acids such as maleic acid, citraconic acid, and itaconic acid, malic acid, tartaric acid, Examples thereof include divalent carboxylic acids having a hydroxyl group such as citramalic acid, saturated trivalent carboxylic acids such as tricarbaryl acid, and trivalent carboxylic acids having a hydroxyl group such as citric acid. These carboxylic acids can be used individually by 1 type, or can also be used in combination of 2 or more type. Among these, citric acid, malic acid, maleic acid, and tartaric acid can be particularly preferably used because they have a large effect of preventing soil accumulation.
Examples of the alkali metal salt of carboxylic acid used in the present invention include lithium salt, sodium salt, rubidium salt, cesium salt and the like. Among these, sodium salts and potassium salts can be preferably used. As the alkali metal salt of the carboxylic acid used in the present invention, any of normal salt, acidic salt, single salt, double salt and the like can be used.

The soil accumulation inhibitor composition in the paper machine of the present invention can be formulated as an aqueous solution or a solution dissolved in a hydrophilic solvent. If necessary, the composition of the present invention may contain a foam suppressant, phosphonic acids, various chelating agents, and the like.
There is no particular limitation on the method of using the soil accumulation inhibitor composition in the paper machine of the present invention. For example, when the composition of the present invention is used to prevent soil from accumulating, the location where the soil accumulates is felt. Is preferably added to the felt shower water, to the roll shower water in the case of various rolls, and to the wire shower water in the case of a wire. The amount added to the shower water can be appropriately selected according to the degree of soiling, but it is usually preferred that the concentration of the drug is 1 to 5,000 mg / L. In the case of felt, the drug per 1 m felt width The amount is preferably 0.1 to 100 mL / min.
In order to remove the dirt already adhered by the dirt removing method in the paper machine of the present invention, it is preferable to add 500 to 100,000 mg / L as a drug amount over 1 to 36 hours. If the amount of the drug is less than 500 mg / L, there is a possibility that the removal of the dirt will be insufficient. When the amount of the drug is 100,000 mg / L or less, the dirt adhering to the paper machine is removed, and it is usually unnecessary to add an amount exceeding 100,000 mg / L as the amount of the drug.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Example 1
A papermaking felt contaminated with rosin sizing agent, aluminum salt of rosin sizing agent and aluminum hydroxide was obtained, cut into a size of 10 cm × 10 cm, dried to obtain a test piece, and a soil removal test was conducted.
8% by weight of an ethylene oxide (27 mol) propylene oxide (30 mol) block copolymer having a structure represented by the general formula [1], 8% by weight of stearylamine ethylene oxide (15 mol) adduct and 9% by weight of citric acid A soil accumulation inhibitor composition A was prepared.
To 500 mL of city water, 2.0 g of the above composition was added to prepare a cleaning solution having a drug concentration of 1,000 mg / L. One test piece was put in this cleaning liquid, stirred at room temperature for 3 hours, washed, and dried at 60 ° C. Subsequently, the test piece was put into a Soxhlet extractor, and extraction was performed for 6 hours using a chloroform-benzene mixed solution (volume ratio 1: 1) as a solvent. When the extract was evaporated to dryness, the amount of the extract obtained as an evaporation residue was 39 mg. An infrared absorption spectrum was obtained for the extract, and a calibration curve prepared in advance was calculated from the ratio of the peak height of the rosin sizing agent peak of about 1,700 cm ^-1 to the peak of the aluminum salt peak of about 1,600 cm ^-1. In comparison, the existence ratio of both was obtained. The weight ratio of rosin sizing agent to aluminum salt of rosin sizing agent was 4: 6.
The felt after extraction with a chloroform-benzene mixture (volume ratio 1: 1) was incinerated, acid-decomposed, aluminum was analyzed by flame atomic absorption, and the amount of aluminum adhering to the felt was calculated. . The amount of aluminum deposited was 16 mg.
The test piece was washed, extracted, analyzed by infrared spectroscopy, and analyzed by atomic absorption in the same manner as above except that tap water to which no chemical was added was used as the cleaning liquid. The evaporation residue was 155 mg, the weight ratio of rosin sizing agent to aluminum salt of rosin sizing agent was 5: 5, and the amount of aluminum deposited was 71 mg. From this result, the residual rate of the solvent extract of the test piece cleaned with the soil accumulation inhibitor composition A is 25% by weight, and the residual rate of adhered aluminum is 23% by weight.

Example 2
4% by weight of ethylene oxide (27 mol) propylene oxide (30 mol) block copolymer having a structure represented by the general formula [1], 14% by weight of stearylamine ethylene oxide (20 mol) adduct and 7% by weight of malic acid The test piece was washed, extracted and analyzed in the same manner as in Example 1 except that the soil accumulation inhibitor composition B contained was used.
The amount of the extract was 38 mg, the residual rate was 25% by weight, the weight ratio of the rosin sizing agent to the aluminum salt of the rosin sizing agent was 3: 7, the amount of adhered aluminum was 21 mg, and the residual rate was 30% by weight.
Example 3
14% by weight of ethylene oxide (14 mol) propylene oxide (16 mol) block copolymer having the structure represented by the general formula [1], 4% by weight of stearylamine ethylene oxide (10 mol) adduct and 7% by weight of malic acid The test piece was washed, extracted and analyzed in the same manner as in Example 1 except that the soil accumulation inhibitor composition C contained was used.
The amount of the extract was 54 mg, the residual rate was 35% by weight, the weight ratio of the rosin sizing agent to the aluminum salt of the rosin sizing agent was 5: 5, the amount of aluminum deposited was 24 mg, and the residual rate was 34% by weight.
Example 4
10% by weight of an ethylene oxide (34 mol) propylene oxide (39 mol) block copolymer having a structure represented by the general formula [1], 10% by weight of tallow amine ethylene oxide (20 mol) adduct, and disodium hydrogen citrate 5 The test piece was washed, extracted, and analyzed in the same manner as in Example 1 except that the stain accumulation inhibitor composition D containing% by weight was used.
The amount of the extract was 42 mg, the residual rate was 27% by weight, the weight ratio of the rosin sizing agent to the aluminum salt of the rosin sizing agent was 4: 6, the amount of aluminum deposited was 24 mg, and the residual rate was 34% by weight.
Example 5
Ethylene oxide (16 mol) propylene oxide (20 mol) block copolymer having a structure represented by the general formula [1] 2.5 wt%, oleylamine ethylene oxide (10 mol) adduct 2.5 wt% and tartaric acid 20 wt% The test piece was washed, extracted and analyzed in the same manner as in Example 1 except that the soil accumulation inhibitor composition E containing 1% was used.
The amount of the extract was 57 mg, the residual rate was 37% by weight, the weight ratio of the rosin sizing agent to the aluminum salt of the rosin sizing agent was 5: 5, the amount of aluminum deposited was 16 mg, and the residual rate was 23% by weight.

Comparative Example 1
Washing, extraction and analysis of test pieces in the same manner as in Example 1 except that the fouling accumulation inhibitor composition F containing 15% by weight of stearylamine ethylene oxide (15 mol) adduct and 10% by weight of citric acid was used. Went.
The amount of the extract was 53 mg, the residual rate was 34% by weight, the weight ratio of the rosin sizing agent to the aluminum salt of the rosin sizing agent was 5: 5, the amount of aluminum deposited was 32 mg, and the residual rate was 45% by weight.
Comparative Example 2
Except for using the soil accumulation preventing composition G containing 10% by weight of an ethylene oxide (27 mol) propylene oxide (30 mol) block copolymer having a structure represented by the general formula [1] and 15% by weight of citric acid In the same manner as in Example 1, the test piece was washed, extracted, and analyzed.
The amount of the extract was 90 mg, the residual rate was 58% by weight, the weight ratio of rosin sizing agent to aluminum salt of rosin sizing agent was 3: 7, the amount of aluminum deposited was 29 mg, and the residual rate was 41% by weight.
Comparative Example 3
The test piece was washed, extracted, and analyzed in the same manner as in Example 1 except that the soil accumulation inhibitor composition H containing 25% by weight of stearylamine ethylene oxide (15 mol) adduct was used.
The amount of the extract was 60 mg, the residual rate was 39% by weight, the weight ratio of the rosin sizing agent to the aluminum salt of the rosin sizing agent was 3: 7, the amount of aluminum deposited was 63 mg, and the residual rate was 89% by weight.
Comparative Example 4
Example 1 was used except that the soil accumulation inhibitor composition I containing 25% by weight of an ethylene oxide (27 mol) propylene oxide (30 mol) block copolymer having a structure represented by the general formula [1] was used. Similarly, the test piece was washed, extracted, and analyzed.
The amount of the extract was 96 mg, the residual rate was 62% by weight, the weight ratio of rosin sizing agent to aluminum salt of the rosin sizing agent was 3: 7, the amount of aluminum deposited was 68 mg, and the residual rate was 96% by weight.
Comparative Example 5
The test piece was washed, extracted and analyzed in the same manner as in Example 1 except that the soil accumulation inhibitor composition J containing 25% by weight of citric acid was used.
The amount of the extract was 127 mg, the residual rate was 82% by weight, the weight ratio of the rosin sizing agent to the aluminum salt of the rosin sizing agent was 5: 5, the amount of adhered aluminum was 27 mg, and the residual rate was 38% by weight.
Table 1 shows the composition of the soil accumulation inhibitor composition used in Examples 1 to 5 and Comparative Examples 1 to 5, and Table 2 shows the results of the cleaning test.

As seen in Table 2, an ethylene oxide-propylene oxide block copolymer having a structure represented by the general formula [1] and a polyoxyethylene alkylamine or polyoxy having a structure represented by the general formula [3] In Examples 1 to 5 using the soil accumulation inhibitor compositions A to E containing ethylene alkyleneamine and carboxylic acid, both the solvent extract and the residual rate of adhered aluminum are low, and the inorganic material adhered to the paper machine Excellent cleaning effect for organic composite stains.
On the other hand, Comparative Example 1 using Composition F that does not contain an ethylene oxide-propylene oxide block copolymer has a high residual rate of adhered aluminum, and Comparative Example 2 that uses Composition G that does not contain polyoxyethylene amine. Then, the residual rate of the solvent extract is high. In Comparative Example 3 using Composition H containing only stearylamine ethylene oxide adduct, the residual rate of adhered aluminum was high, and in Comparative Example 4 using Composition I containing only ethylene oxide-propylene oxide block copolymer, solvent was used. Both the extract and the adhered aluminum have a high residual rate, and in Comparative Example 5 using the composition J containing only citric acid, the residual rate of the solvent extract is high.

Example 6 (actual machine test)
An actual machine test was conducted in the paper making process, in which printing paper was made using a long paper machine. In this step, conventionally, a 20% by weight aqueous solution of an ethylene oxide (25 mol) propylene oxide (30 mol) block copolymer having a structure represented by the general formula [1] is added to a papermaking felt at 3 mL / min / It was added in m width. However, the felt and suction box were soiled with the aluminum salt of the rosin sizing agent, and the vacuum degree of the suction box deteriorated, the pitch adhered to the suction box lip, and the paper was cut due to the pitch.
Therefore, 8% by weight of ethylene oxide (25 mol) propylene oxide (30 mol) block copolymer represented by the general formula [1], 8% by weight of stearylamine ethylene oxide (15 mol) adduct and 9% by weight of citric acid are contained. The soil accumulation inhibitor composition of the present invention was added to a paper felt felt shower water at a width of 3 mL / min / m. As a result, the vacuum degree of the suction box was lowered from -54.7 kPa to -53.3 kPa and stabilized. Also, there was no pitch adhesion on the suction box lip, and no paper break occurred.

  According to the stain accumulation inhibitor composition and the stain accumulation prevention method of the paper machine of the present invention, even in a papermaking system in which complicated stains are likely to occur, the accumulation of stains is effectively prevented, and high quality products are stabilized. Paper. Furthermore, according to the dirt removal method in the paper machine of the present invention, the dirt of the paper machine that has already adhered can be removed.

Claims (5)

A non-ionic surfactant composition comprising a nonionic surfactant and a carboxylic acid or an alkali metal salt thereof in a weight ratio of 1: 9 to 9: 1 in a paper machine, wherein the nonionic surfactant An ethylene oxide-propylene oxide block copolymer having a structure represented by general formula [1] or general formula [2] and a polyoxyethylene alkylamine or polyoxyethylene having a structure represented by general formula [3] A composition for preventing accumulation of dirt in a paper machine, comprising an alkyleneamine.
_{HO- (C 2 H 4 O)} a - (C 3 H 6 O) b - (C 2 H 4 O) c H ... [1]
(However, in the formula, a + c is 10 to 40, a and c are not 0, and b is 15 to 45.)
_{HO- (C 3 H 6 O)} d - (C 2 H 4 O) e - (C 3 H 6 O) f H ... [2]
(However, in the formula, d + f is 10 to 45, d and f are not 0, and e is 10 to 40.)
R—NH— (C ₂ H ₄ O) _g H [3]
(In the formula, R is an alkyl group or alkenyl group having 12 to 22 carbon atoms, and g is 5 to 30.)   2. The soil accumulation preventing composition for a paper machine according to claim 1, wherein the carboxylic acid is a water-soluble polyvalent carboxylic acid. The composition for preventing accumulation of dirt in a paper machine according to claim 2 , wherein the water-soluble polyvalent carboxylic acid is citric acid, malic acid, maleic acid or tartaric acid. A soil accumulation preventive composition in a paper machine according to any one of claims 1 to 3 is added to a shower water system of the paper machine at a concentration of 1 to 5,000 mg / L. Prevention method. The stain accumulation preventing composition in a paper machine according to any one of claims 1 to 3 is added to a shower water system of a paper machine to which dirt is attached so that the concentration of the composition is 500 to 100,000 mg / L. A method for removing dirt in a paper machine, characterized by comprising: