JPH08176996A - Method for preventing slime fault from occurring in pulp factory and paper manufacturing factory - Google Patents

Abstract

PURPOSE: To prevent lowering of paper quality due to stains and spots and troubles due to slime such as malodor by adding a hydantoin-based compound to a process water to kill bacteria constituting slime or inhibit growth of bacteria. CONSTITUTION: A hydantoin-based compound represented by the formula (at least either one of R<1> and R<2> is Cl or Br and the other is H, Cl or Br, preferably either one is Cl and the other is Br; R<3> and R<4> are each H or a 1-12C alkyl, preferably each methyl) in an amount of 0.1-100 ppm, preferably 0.5-50 ppm, more preferably 1-20 ppm is added to a process water such as white water in pulp factory or papermaking factory, especially, alkali paper-based white water to effectively carry out killing or growth inhibition of bacteria constituting slime even if pH of the process water is present on acidic side of 4-6 or in high pH region of 6-8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing slime damage occurring in process water of pulp and paper factories.

[0002]

2. Description of the Related Art It is well known in pulp mills and paper mills that the proliferation of microorganisms in the water used in the process causes various problems.
For example, white water discharged from a paper machine contains pulp, which is a nutrient source for fungi, and various chemicals and fillers are added. It is in a convenient environment. When microorganisms propagate in white water, the microorganisms and their metabolites aggregate to form a sticky substance, so-called slime, and when it grows to a certain size, it peels off due to the flow rate of process water and mixes into the paper stock. ,
The quality of the product such as stains, spots, and eyeballs will be impaired on the paper, and further, paper scraps, clogging of wires and blankets, corrosion,
It will cause bad odors and other problems, and will seriously affect the operation. Since the process water directly contacts the paper of the product and is partially taken in by the paper as described above, the slime generated there is often a more serious problem than that in general cooling water or water.

Paper making methods include a so-called acidic paper making method in which a sizing agent and a sulfuric acid band as a fixing agent are used in combination, and an alkaline paper making method in which calcium carbonate is used as a filler. Conventionally, an acidic papermaking method having a pH of 4 to 6 has been the mainstream, but recently, an alkaline papermaking method having a pH of 6 to 8 has been increasing. The alkaline papermaking method has many advantages in that white water can be closed and inexpensive calcium carbonate can be used as a filler. However, on the other hand, when the papermaking method is changed to the alkaline papermaking method in this way, the rise of water temperature due to the closing of white water, the concentration of nutrients, the attachment of fillers, etc. serve as a habitat for microorganisms, and in addition, the optimal microorganisms for slime formation pH of 6-8, etc.
It has also been pointed out that slime is much more adhered than in the conventional acidic papermaking method, and the environment is such that it easily grows.
In addition, recycled paper is drawing attention due to environmental issues such as the protection of forest resources, and the percentage of used paper tends to increase. In the use of waste paper, various chemicals are added in large amounts in order to improve the quality and yield of the paper, and the inside of the system is easily soiled.

Various microbicides have been proposed in the past for the control of microorganisms in the process water of pulp mills and paper mills and the prevention of slime disorders. For example, 2,2-dibromo-3-nitrilopropionamide, 1,4 bisbromo. An organic Br compound represented by acetoxy-2-butene, 5-chloro-2-methyl-4-isothiazolone-3
There are proposed isothiazolone compounds represented by a mixture of 1-one and 2-methyl-4-isothiazolone-3-one, α-chlorobenzaldoxime (JP-A-6-49797) and the like. However, the operating conditions are changing due to social and economic reasons in which the paper and pulp industry is placed, such as the difference in papermaking methods and the increase in the percentage of used paper, and slime obstacles are diversifying. As a result, conventional microbicides are not satisfactory, and more improved ones are required. For example, it is known that conventional microbicides have a certain degree of efficacy in an acidic papermaking system, but the microorganisms are likely to have drug resistance, and the microorganisms resistant to the drug tend to be prioritized. If you try to make it even more effective,
A large amount of drug must be administered, which is not practical in terms of processing cost. In the alkaline papermaking system, a conventional microbicide has been developed for acidic papermaking, and therefore, it tends to show a decrease in efficacy under alkaline conditions.To obtain the same effect as the acidic papermaking system, use a large amount of chemicals. Unless it is effective, it is in a situation where it cannot be practically used in terms of processing cost. Under such circumstances, there is a demand for a slime failure prevention method which has a stable effect regardless of the papermaking method and does not affect the product quality.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a slime failure prevention method that can withstand a new environment in view of the above-mentioned changes in the operating conditions of the paper and pulp industry.

[0006]

DISCLOSURE OF THE INVENTION The present inventors have taken into consideration the problems of the above-mentioned conventional methods,
As a result of earnest research to overcome newly emerging problems such as increasing the ratio of waste paper, by adding a specific hydantoin compound to process water, regardless of the papermaking method,
We have completed this study by discovering that it has a lower concentration than conventional microbicides and that it kills and inhibits growth of slime-composing bacteria without impairing product quality.

That is, the present invention is applicable to general formula (I) in process water in pulp mills and paper mills. (In the formula, R ¹ and R ² may be the same or different, at least one is a chlorine or bromine atom, and the other is a hydrogen atom, a chlorine atom or a bromine atom, and R ³ and R ^{4 are} May be the same or different and each represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.)
A method for preventing slime disorders, which comprises adding a hydantoin compound represented by to killing or inhibiting growth of slime-constituting bacteria.

In the above general formula (I), R ¹ and R ²
May be the same or different and at least one is a chlorine atom or a bromine atom, and the other is a hydrogen atom, a chlorine atom or a bromine atom. R ³ and R ⁴ may be the same or different and each represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, preferably 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, n-hexyl group, 2-ethylhexyl group, n-octyl group, n-dodecyl group. And so on.
An alkyl group having 13 or more carbon atoms is not preferable because the water solubility of the hydantoin compound becomes extremely poor. Specific examples of the hydantoin compound represented by the above general formula include 1-bromo-3-chloro-5,5-dimethylhydantoin, 1,3-dibromo-5,5-diethylhydantoin and 1,3-dibromo-5. -Methyl-5-butylhydantoin, 1-bromo-3-chlorohydantoin, 1,
Examples thereof include 3-dichloro-5,5-dimethylhydantoin.

Process water in the pulp mill / paper mill of the present invention includes process water generally called so-called white water, which is discharged mainly from the crushing process, the papermaking process, the screen process, the bleaching process, etc. It contains all the water handled in the paper mill process. The amount of hydantoins added to the water system is not uniformly determined depending on the water quality of the water system, the number of viable microorganisms, the degree of slime generation, the type of the hydantoin compound, the addition frequency, etc., but it is usually the water of the water system. To 0.1 to 100 ppm, preferably 0.5 to
It is 50 ppm, more preferably 1 to 20 ppm.
If it is less than 0.1 ppm, the effect is substantially small, and if it is more than 100 ppm, the effect is sufficient, but the effect is not large relative to the addition amount, which is economically disadvantageous. The above concentration of the hydantoin compound that kills and inhibits slime-forming bacteria does not affect the process and does not impair the quality of the product.

The hydantoin compound used in the present invention is solid at room temperature and generally has a solubility of about 0.1 to 0.2% by weight in water. In addition to the water system, the hydantoin compound may be added to the water system in the form of powder, or may be dissolved in water and then added. When considering the ease of addition to the process, it dissolves in water,
It can be said that it is preferable to use a pump or the like to inject it into a required portion of the process. It can be dissolved in an organic solvent, particularly an organic solvent compatible with water, for example, acetone, dioxane, dimethylformamide, N-methylpyrrolidone, etc., but the presence of the organic solvent in the water system is a nutrient source for microorganisms. It can be said that it is not preferable. Also,
When used by dissolving in water or an organic solvent, it is preferable to add it into the system as soon as possible after being dissolved, considering the stability of the hydantoin compound. The addition to the water system includes a method of impact addition in which a high concentration is added at regular intervals, a method of intermittent addition, or a method of continuously adding and keeping a constant concentration at all times, and is not particularly limited. It may be added so that the number of surviving microorganisms is kept below a certain amount and a level at which slime damage does not occur.

[0011]

The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention. Example 1 As a representative bacterial species detected in white water from a papermaking process at a paper mill, a gram-negative bacterium Pseudomonas.
p), and Gram-positive bacterium Bacillus.sp, and 32 in TGY liquid medium (pH = 7.0), respectively.
Pre-culture was carried out at ℃ for 24 hours. The obtained culture solution is diluted 100 times with sterilized water to adjust the pH (pH = 5, 6, 7, 8, 9)
A bacterial suspension was obtained. . 100 mL of this suspension is added to 300
The mixture was placed in a mL Erlenmeyer flask, a predetermined concentration (10 ppm) of the microbicide was added, and the mixture was contacted with a shaker for 0.5 hours. After that, the cells were inoculated into TGY agar medium and cultured at 32 ° C. for 3 days, and the viable cell count per 1 mL of white water was measured. The results are shown in Table 1 together with the comparative example. Hydantoin compounds are
It can be seen that the viable cell count is significantly reduced compared to the compounds used for comparison. In particular, the difference is remarkable at high pH.

[0012]

[Table 1]

Example 2 White water (pH = 5.
4 Viable cell count: 2 × 10 ⁷ cells / mL) was collected in 300 mL Erlenmeyer flasks by 100 mL, and a predetermined amount (0.1, 1, 10, 30, 100) of the microbicide was added to each sample.
ppm) and contacted with a shaker for 0.5 and 1 hour. After that, it was inoculated into TGY agar medium and cultured at 32 ° C. for 3 days, and the viable cell count per 1 mL of white water was measured. The results are shown in Table 2 together with the comparative example. Hydantoin compounds are
It can be seen that the viable cell count is significantly reduced compared to the compounds used for comparison.

[0014]

[Table 2]

Example 3 In the same manner as in Example 2, a test was conducted using white water (pH = 8.0 viable cell count: 1 × 10 ⁹ cells / mL) of an alkaline papermaking machine in a paper mill. The results are shown in Table 3 together with the comparative example. It can be seen that the hydantoin compound has a significantly reduced live cell count compared to the compound used for comparison. In particular, the white water of the alkaline papermaking machine is significantly different from the comparative example as compared with the white water of the acidic papermaking machine.

[0016]

[Table 3]

[0017]

EFFECTS OF THE INVENTION According to the method of the present invention, by preventing or inhibiting the growth of slime-constituting bacteria that grow in process water of pulp mills and paper mills, the slime disorder occurring in the process is prevented. You can PH of process water is 4
The effect can be sufficiently exerted not only on the acidic side of ~ 6 but also in the high pH range where the pH is 6-8.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location C02F 1/50 520 P 532 C DH C02F 1/50 540 D (71) Applicant 594209382 Great Lakes Chemical Corporation Great Lakes Chemical Corporation 47,906, West Lafayette, North West, Highway 52, Post Office Box 2200 # Post Office Box 2200, Highway 52 N. W. , West Lafayette, Indiana 47906, Unite States of America (72) Inventor Hideki Takahashi Yokkaichi City, Mie Prefecture 6-6-9 Hakuto Co., Ltd. Yokkaichi Laboratory (72) Inventor Yasuhiro Nobata 6-Yokaichi, Mie Prefecture 6-9 Hakuto Co., Ltd. Yokkaichi Research Institute (72) Inventor Richard Ellesmore, Ellesmere Port of England, El 65.4 Geedie, South Wheelal, Oil Sites Road, Poo Boxes 44, Great Inside the Lakes Chemical Corporation

Claims (3)

[Claims] 1. The general formula (I) in process water in a pulp mill / paper mill. (In the formula, R ¹ and R ² may be the same or different, at least one is a chlorine or bromine atom, and the other is a hydrogen atom, a chlorine atom or a bromine atom, and R ³ and R ^{4 are} May be the same or different and each represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.)
A method for preventing slime disorders, which comprises adding a hydantoin compound represented by the formula (3) to kill or inhibit growth of slime-constituting bacteria. 2. The method for preventing slime disorders according to claim 1, wherein the process water is white water discharged from an alkaline paper machine. 3. The slime obstacle according to claim 1, wherein one of R ¹ and R ² in the general formula (I) is a chlorine atom and the other is a bromine atom, and both R ³ and R ⁴ are methyl groups. Prevention method.