JPH01163106A - Agent for controlling slime of paper mill - Google Patents

Abstract

PURPOSE:To obtain a slime-controlling agent for industrial water of a paper mill, having synergistically improved slime-controlling effect, by using methylenebisthiocyanate in combination with a 2-methylisothiazolin-3-one compound or its metal complex salt compound. CONSTITUTION:The objective agent contains (A) methylenebisthiocyanate and (B) a 2-methylisothianazolin-3-one compound of formula (X is H or Cl) or its metal complex salt compound as active components. The weight ratio of A:B (the compound of formula I) is 95:5-5:95, preferably 90:10-10:90. The slime- controlling agent obtained by this process exhibits excellent synergistic effect which cannot be expected by the separate use of each component. It continues sufficient activity even under a condition liable to lower the activity of the controlling agent by the development of a resistant bacteria or a microbial substitution phenomenon caused by the improvement in the recovery of white water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a slime control agent in industrial water used in paper manufacturing processes.

It is known that slime is formed by the proliferation of microorganisms such as bacteria, yeast, and filamentous fungi in the pulp preparation and papermaking processes of pulp and paper mills, causing various problems.

Slime adheres to almost every part of the process that uses water, such as riffler walls, screens, inlets, chest walls, white water bits, and the inner walls of recovery white water pipes during the papermaking process, gradually increasing its thickness and eventually peeling off. It can get mixed into pulp slurry and clog screens and pipes. Small slime lumps mixed into the pulp slurry cause yellow or brown spots, so-called eyeballs, on the paper, degrading the paper quality, and large slime lumps can even cause the paper to break.

In recent years, there has been an increase in pitch-like deposits due to improved white water recovery rates, eutrophication due to additives such as starch and polyacrylamide, deposits containing inorganic fillers, resin components of wood, adhesives derived from waste paper, etc. As a result, the paper manufacturing process has become an environment suitable for the growth of microorganisms. In particular, improvement in the white water recovery rate makes it easier for bacteria resistant to slime control agents to appear and for bacterial replacement to occur, causing a decrease in the efficacy of slime control agents. Although many slime control agents have been developed and used in the past, there are currently almost no slime control agents that can maintain sufficient efficacy under such conditions.

The present inventor has discovered that by using methylene bisthiocyanate together with a 2-methylinthiazolin-6-one compound represented by the general formula (wherein X represents a hydrogen atom or a chlorine atom) or a metal complex salt thereof, It has been discovered that an excellent synergistic effect can be obtained that could not be expected from the use of the compounds alone.

As the 2-methylisothiazolin-6-one compound of general formula I, 5-chloro-2-methylisothiazolin-6
-one or 2-methylisothiazolin-6-one. Examples of metal salts that form metal complexes with these include magnesium chloride, magnesium nitrate, sodium chloride, copper nitrate, and the like. These compounds are commercially available and readily available. For example, 5-chloro-2-
As a metal complex salt of methylinthiazolin-3-one,
Caisson WT (trade name) manufactured by Rohm & No. This product is an aqueous solution containing approximately 14% of 2-methylisothiazolin-6-one compound.
A mixture of 5-chloro-2-methylisothiazolin-6-one and 2-methylisothiazolin-3-one (approximately 3:
1), it forms a metal complex salt with magnesium chloride and magnesium nitrate. Moreover, as a 5-chloro-2-methylisothiazolin-3-one compound, Zonen manufactured by Ichikawa Gosei Chemical Co., Ltd. is known. This product contains about 14% of a mixture of 5-chloro-2-methylisothiazolin-3-one and 2-methylisothiazolin-6-one, and the blending ratio with the organic solvent isothiazolin-3-one compound is as follows: 95=5 to 5:95 preferably 9
The time is from 0:10 to 10:90.

The slime control agent of the present invention is usually used by dissolving methylene bisthiocyanate and the 2-methylisothiazolin-3-one compound of formula I in an organic solvent, but it is suspended in water using a thickening agent such as xanthan gum. It can also be used.

Examples of organic solvents include alcohols such as methanol, ethanol, and isopropyl alcohol, ethylene glycol,
Propylene glycol, diethylene glycol sodium glycol, ethylene glycol monomethyl ether;
≠#≠≠ Ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol motsubutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monopropyl ether, methoxypolyethylene glycol, etc. Glycol ether, dimethylformamide, dimethyl sulfoxide, etc. are used.

The amount of the slime control agent of the present invention added to the papermaking process varies depending on the water source, papermaking material, etc., but generally it is sufficiently effective at 0.1 to 100 ppm of the active ingredient in the water.

The composition of the formulation example is as follows.

Formulation example 1 Methylene bisthiocyanate 10 parts Zonen 8 parts Diethylene glycol monomethyl ether 82 parts Formulation example 2 Methylene bis thiocyanate (fine powder) 10 parts Caisson WT 20 parts Xanthan gum 0.2 parts Water
69.8 parts Formulation Example 6 Methylene bisthiocyanate 10 parts Zonen 30 parts Ethylene glycol 20 parts Methoxypolyethylene glycol 40 parts (average molecular weight 210~
240) Formulation Example 4 Methylene bisthiocyanate 5 parts Zonen 50 parts Methoxypolyethylene glycol 45 parts Test Example 1 Slime collected from the stock inlet during the corrugated pole center papermaking process was precultured in Waxman liquid medium to prepare a test bacterial solution. Add 10 ml of Waxman liquid medium and 4 Q ml of sterile water as a culture medium to a shaking flask with a capacity of 100 ml. The active ingredient of the test drug is 2 ppm based on the culture solution.
Add 10ml of test bacteria solution to make 67.
Cultured with shaking at °C. The absorbance of this culture solution at 660 nm was measured over time, and the degree of inhibition of slime-forming bacteria propagation was compared. The test agent was prepared by dissolving methylene bisthiocyanate and caisson WT in diethylene glycol monomethyl ether, and was diluted with methanol to an appropriate concentration at the time of addition. The results are shown in Table 1.

The suppression time in the table indicates the time required for the absorbance of each culture solution to reach a value of 0.1, and the stronger the efficacy, the longer the suppression time. Experiment numbers 2 to 6 in the table are examples of the present invention,
The others are comparative examples.

Table 1 *: Calculation Test Example 2 A test was conducted in the same manner as Test Example 1, with the content of compound (■) being 14%. Methylene bisthiocyanate and zonen were used as the test chemicals.

The results are shown in Table 2.

Experiment numbers 10 to 14 in the table are examples of the present invention, and the others are comparative examples.

Table 2 *: Calculation assuming the content of compound ■ is 149 mm Test Example 6 A stainless steel water tank with a diameter of 60 Crn and a depth of 60 cm, a temperature control device, a stirrer, a thermometer, and a slime measurement plate with a width of 5 cm, a length of 3 Q Crn, and a thickness. Two pieces of lauan wood with a length of 1.5 cm were taken lengthwise and attached. After adding 1% pulp and a white water culture solution (a culture solution obtained by culturing white water collected from the paper manufacturing process in a Waxman liquid medium) to a 1000-fold diluted Waxman liquid medium at a rate of 0.1 ml/e, Artificial white water adjusted to pH 5 with aluminum sulfate was supplied to this tank at a flow rate of 2-e/hour, and the same amount of artificial white water was discharged. The same test agent as in Test Example 1 was added using a pump three times a day for 3 hours each time so that the active ingredient was 4 ppm based on the supplied artificial white water. Stirring was continued while keeping the white water temperature at 60° C., and the slime control effect was evaluated after about 10 days. The white water used for the white water culture solution was two types: white water (A) collected from the cardboard center paper manufacturing process and white water CB collected from the newsprint paper manufacturing process. The plan was to visually observe the slime measurement board and score the amount of slime adhesion using a 10-point scale.

The outline of the scoring criteria is as follows.

0: No slime is observed at all. 5. A thin layer of slime is adhered to the entire surface. 10. A thick layer of slime is adhered to the entire surface, with some parts peeling off. The amount of slime attached varies depending on the white water used and other conditions. Therefore, it is a relative and comprehensive evaluation with no slime control agent added and the comparative example. The results are shown in Table 6. Experiment numbers 18 to 22 in the table are examples of the present invention, and the others are comparative examples.

Table 6 Test Example 4 The test was conducted in the same manner as in Test Example 6 except that the same drug as in Test Example 2 was used as the test drug.

The results are shown in Table 4. Experiment numbers 26 to 30 in the table are examples of the present invention, and the others are comparative examples.

Table 4 Applicant: Permakem Asia Co., Ltd. Agent: Patent Attorney Masao Hayashi 1 other person

Claims (1)

[Claims] Methylene bisthiocyanate and a 2-methylisothiazolin-6-one compound or its metal represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (wherein X represents a hydrogen atom or a chlorine atom) A slime control agent for paper manufacturing, characterized by containing a complex salt compound as an active ingredient.