JP2006273801A - Industrial antibacterial composition and antibacterial method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an industrial antibacterial composition high in saftey and antibacterial force, and specially, exhibits satisfactory antibacterial force even under alkaline condition, and an antibacterial method. <P>SOLUTION: The industrial antibacterial composition contains sodium pyrition and 2-methyl-4-isothiazolin-3-one, and is used under an alkaline condition of pH 7 or higher. Specially, it is preferable that sodium pyrition and 2-methyl-4-isothiazolin-3-one are dissolved in water to make them an aqueous liquid agent of an alkalinity of pH 9-11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an industrial antibacterial composition containing at least two substances as active ingredients and an antibacterial method using the industrial antibacterial composition.

  Conventionally, as an industrial antibacterial composition, 2,2-dibromo-3-nitrilopropionamide (hereinafter “DBNPA”), 1,4-bis (bromoacetoxy) -2-butene (hereinafter “BBAB”), and 5-Chloro-2-methyl-4-isothiazolin-3-one (hereinafter “CL-MIT”) and the like are used. These substances show an excellent antibacterial effect when neutral or acidic, but are markedly decomposed when alkaline.

  On the other hand, 1,2-benzisothiazolin-3-one (hereinafter “BIT”), triazine, and sodium pyrithione (hereinafter “NaPT”), which are also used as industrial antibacterial compositions, are alkaline and stable. However, BIT has a problem that when the pH is 9 or more, it undergoes a structural change and the antibacterial activity is greatly reduced, and triazine releases formalin. Furthermore, NaPT alone has a problem that its antibacterial effect is low.

  Then, the industrial antibacterial composition which improved antibacterial power by combining 2-3 types of substances is proposed (for example, patent documents 1). Patent Document 1 discloses an industrial antibacterial composition in which 4,5-dichloro-n-octyl-4-isothiazolin-3-one (hereinafter “DCOIT”) and NaPT are combined. The industrial antibacterial composition disclosed in Patent Document 1 exhibits a high antibacterial activity even at a low concentration due to a synergistic effect of NaPT and an isothiazolin-3-one compound.

  However, since DCOIT does not dissolve in water, an organic solvent must be used when using a substance that does not dissolve in water, such as DCOIT. When a solvent-type product dissolved in an organic solvent is applied to an aqueous emulsion such as latex, emulsion shock is caused by the solvent to cause aggregation. For this reason, products using organic solvents are often difficult to apply. From such circumstances, when the application target is aqueous, it is desirable that the antimicrobial composition is also aqueous.

  By the way, in the substance used as an industrial antibacterial composition, the antibacterial effect and safety are contradictory, and the substance excellent in antibacterial activity tends to have a problem in safety, for example, having mutagenicity. For example, among isothiazolin-3-one compounds, CL-MIT has a high antibacterial effect but is known to have a safety problem such as being mutagenic or prone to allergies. -Isothiazoline-3-one (hereinafter "MIT") is highly safe but has an antibacterial effect inferior to CL-MIT.

Moreover, since MIT is unstable when made into an aqueous preparation, a stabilizer is necessary to obtain a stable aqueous preparation over a long period of time (Patent Document 2).
JP 2003-63916 A Japanese Patent Laid-Open No. 3-188071

  The present invention has been made in view of the above problems, and has an object to provide an industrial antibacterial composition and an antibacterial method that have high safety and antibacterial activity, exhibit sufficient antibacterial activity under alkaline conditions, and do not cause aggregation. To do.

  The inventor of the present invention can obtain a high antibacterial effect due to a synergistic effect under alkaline conditions by combining MIT having a low antibacterial effect alone with NaPT. In particular, an aqueous liquid preparation in which MIT and NaPT are dissolved in water is a stabilizer. The present invention has been completed by discovering that an alkaline solution can be used for a long period of time without using an antibacterial agent and exhibits a high antibacterial effect. Specifically, the present invention provides the following.

  (1) An industrial antibacterial composition containing sodium pyrithione and 2-methyl-4-isothiazolin-3-one and added to an alkaline antibacterial solution having a pH of 7 or higher.

  (2) An industrial antibacterial composition in which sodium pyrithione and 2-methyl-4-isothiazolin-3-one are dissolved in a solvent containing water to form an aqueous liquid having a pH of 7 or more.

  (3) The industrial antibacterial composition according to (1) or (2), wherein the pH is 9 to 11.

  (4) The sodium pyrithione and the 2-methyl-4-isothiazolin-3-one are contained in a weight ratio of 4: 1 to 1: 4 according to any one of (1) to (3) Industrial antibacterial composition.

  (5) An antibacterial method of adding sodium pyrithione and 2-methyl-4-isothiazolin-3-one to an alkaline antibacterial target solution having a pH of 7 or higher.

  (6) The antibacterial according to (5), wherein the sodium pyrithione and the 2-methyl-4-isothiazolin-3-one are dissolved in a solvent containing water and added to the alkaline antibacterial target solution as an aqueous liquid having a pH of 7 or more. Method.

  (7) The antibacterial method according to (5), wherein the sodium pyrithione and the 2-methyl-4-isothiazolin-3-one are separately added to the alkaline antibacterial liquid.

  (8) The antibacterial method according to any one of (5) to (7), wherein the alkaline antibacterial target liquid has a pH of 9 to 11.

  (9) The sodium pyrithione and the 2-methyl-4-isothiazolin-3-one are added to the alkaline antibacterial liquid at a weight ratio of 4: 1 to 1: 4 (5) to (8 ) The antibacterial method according to any one of the above.

  The industrial antibacterial composition according to the invention described in (1) is added to an alkaline liquid having a pH of 7 or more, particularly a pH of 9 to 11. In the present specification, “liquid” includes a suspension (slurry), and specific examples of the alkaline antibacterial target liquid include alkaline slurry, coating liquid, and water-based paint containing calcium carbonate, clay, kaolin, or bentonite. , Latex emulsions, polymer emulsions, metalworking oils, fiber oils, thickening polysaccharides and adhesives.

  By coexisting sodium pyrithione (NaPT) and 2-methyl-4-isothiazolin-3-one (MIT) under alkaline conditions, the degradation of MIT that is easily decomposed under aqueous conditions is suppressed, and a synergistic effect is obtained. For this reason, when NaPT and MIT are used under alkaline conditions, the growth of bacteria in the antibacterial solution can be suppressed over a long period of time at a lower concentration than when NaPT or MIT is used alone.

  The industrial antibacterial composition can be added to the antibacterial target liquid as a preparation of any form such as a liquid agent, a powder agent, an emulsifier, and a flowable agent. NaPT and MIT may be formulated separately, or mixed and formulated. The solvent used for formulation is not particularly limited, and either a polar solvent or a nonpolar solvent may be used. Specifically, water, alcohol solvents, glycol solvents, and glycol ether solvents are listed as polar solvents, and toluene, paraffin, xylene, and vegetable oils are listed as nonpolar solvents.

  It is particularly preferable to use water as the solvent. Specifically, as in the invention described in (2), NaPT and MIT are dissolved in a solvent containing water, and the pH is 7 or more, preferably described in (3). It is preferable to use an aqueous liquid having a pH of 9 to 11 as in the invention. The pH of the aqueous solution is such that after NaPT and MIT are dissolved in water, an alkali such as sodium hydroxide, potassium hydroxide, ammonia, calcium hydroxide, and sodium carbonate, or an inorganic acid such as hydrochloric acid or sulfuric acid, or citric acid, etc. It can adjust by adding the organic acid.

  The solvent may contain additives such as surfactants and stabilizers, but preferably contains 50% by weight or more of water and does not substantially contain an organic solvent. There is no restriction | limiting in particular as surfactant or stabilizer added to a solvent. Specific examples of the surfactant include anionic surfactants such as metal salts of alkylbenzene sulfonic acid and alkyl naphthalene sulfonic acid, nonionic surfactants such as polyoxyethylene alkyl phenyl ether and polyoxyethylene nonyl phenyl ether, fat And cationic surfactants such as aromatic amine salts and amphoteric surfactants such as aminocarboxylates. Examples of the stabilizer include alkali metal nitrates.

  When adding a surfactant, the addition concentration is preferably 0.1 to 10% by weight based on the solvent. Moreover, it is preferable that the density | concentration in the whole additive which does not have antimicrobial power, such as surfactant and a stabilizer, is less than 2 weight%.

  By dissolving NaPT and MIT in a solvent containing water to make them alkaline, a high antibacterial effect due to the synergistic effect of these two components can be obtained, and decomposition of MIT can be suppressed. For this reason, the alkaline aqueous liquid agent containing NaPT and MIT can exhibit the antibacterial effect stably for a long period of time. In addition, since such an aqueous solution does not contain an organic solvent, it can be produced at a low cost, has a low burden on the human body and the environment, and has a good compatibility when added to latex or a coating solution, and can prevent emulsion aggregation.

  The aqueous solution contains NaPT at a concentration of 5 to 40% by weight and MIT at a concentration of 10 to 40% by weight, and the blending ratio of both is NaPT: in the range defined by the invention described in (4), that is, by weight ratio. It is preferable that MIT is 4: 1 to 1: 4.

  When the antibacterial method according to (5), in which the industrial composition according to the present invention is added to an alkaline antibacterial solution, the concentration of NaPT in the antibacterial solution is 1 to 1,000 mg / L, and the concentration of MIT Is 1 to 1,000 mg / L, and NaPT and MIT are preferably used in a weight ratio of 4: 1 to 1: 4. NaPT and MIT may be formulated separately as in the invention described in (7) and added alternately to the antibacterial target solution, or both are mixed in advance as in the invention described in (6) May be added to the antibacterial solution. In order to use NaPT and MIT under alkaline conditions, if necessary, alkali may be added to the antibacterial solution to adjust the pH of the antibacterial solution, and NaPT and MIT are dissolved in an alkaline solvent in advance. You may use it.

  According to the present invention, a stable antibacterial effect can be obtained for a long period of time by using NaPT and MIT under alkaline conditions. NaPT and MIT are both highly safe substances, and the industrial antibacterial composition according to the present invention has a low burden on the human body and the environment. Furthermore, since NaPT and MIT exert a synergistic effect under alkaline conditions, according to the present invention, a high antibacterial activity can be obtained at a lower concentration than when NaPT or MIT is used alone.

  Hereinafter, the present invention will be described in detail based on examples.

[Antimicrobial test]
In order to evaluate the antibacterial properties of the industrial antibacterial composition according to the present invention, performance tests 1 to 12 were performed. Antibacterial performance was evaluated by using an aqueous solution of NaPT 45% and an aqueous solution of MIT 50% as an industrial composition, either alone or in combination, and changing the concentration to a medium inoculated with bacteria to obtain a minimum growth inhibitory concentration. As the test bacteria, Porphyrobacter sp. Isolated from calcium carbonate slurry and Pseudomonas pseudoalcaligenens isolated from color coating solution were used. A mixed liquid medium (pH 9, hereinafter “PY medium”) was used. The cell concentration in the medium at the start of the test was 4.5 × 10 ⁵ cells / ml for the test using Porphyrobacter sp. And 1.1 × 10 ⁶ cells / ml for the test using Pseudomonas pseudoalcaligenens. there were.

  For performance tests 1 to 6, Porphyrobacter sp. Was used as a test bacterium, and in performance tests 7 to 12, Pseudomonas pseudoalcaligenens was used as a test bacterium. For performance tests 1 to 6, the concentrations of NaPT and MIT added to the medium are shown in Table 1, and the test results are shown in FIG. For performance tests 7 to 12, the addition concentrations of NaPT and MIT are shown in Table 2, and the results are shown in FIG.

  FIG. 1 and FIG. 2 are graphs showing the results of testing the dual growth inhibitory concentration indicating the minimum growth inhibitory concentration against Porphyrobacter sp. Or Pseudomonas pseudoalcaligenens when NaPT and MIT are used alone or in combination. Here, the effects of antimicrobial agents used against microorganisms such as bacteria and sputum are broadly divided into bacteriostatic action that inhibits the growth of microorganisms and bactericidal action that kills microorganisms. This is to evaluate the bacteriostatic action of microbial agents. Specifically, as the concentration of the antimicrobial agent is increased, the growth inhibitory action on the microorganism is increased and the growth rate of the microorganism is decreased. The minimum growth inhibitory concentration is a minimum addition concentration of an antimicrobial agent necessary for increasing the concentration of the antimicrobial agent added to the microorganism and stopping the growth of the microorganism.

  In these figures, the minimum inhibitory concentration when NaPT or MIT is used alone is plotted on the X-axis and Y-axis, respectively, and the minimum inhibitory concentration of the industrial antibacterial composition using NaPT and MIT in combination is plotted on the coordinates. Is plotted in And when NaPT or MIT is used alone, the minimum inhibitory concentration plotted on the X-axis or Y-axis is connected by a straight line, and the minimum inhibitory concentration of the industrial antibacterial composition using NaPT and MIT together is this When plotted on a straight line, it indicates that an additive effect has been obtained, and when plotted below this line, a synergistic effect is obtained, and when plotted above this line, an antagonistic effect is achieved. Indicates that

  As shown in FIG. 1, the results of Tests 2 to 5 using NaPT and MIT in combination are plotted under the above straight line. By using NaPT and MIT under alkaline conditions of pH 9 or higher for Porphyrobacter sp. It was shown that a synergistic effect was obtained. Similarly, as shown in FIG. 2, the results of Tests 8 to 11 using NaPT and MIT in combination with Pseudomonas pseudoalcaligenens are plotted below the straight line, indicating that a synergistic effect is obtained.

[Examples 1 to 16]
As an example, NaPT and MIT used in the above antibacterial test were dissolved in water at different concentrations and blending ratios, and the pH was adjusted to about 9.4 using sodium hydroxide to obtain an alkaline aqueous solution. It added to the circulation color coating liquid (pH 9.4) which is antibacterial object liquid. Next, the coating solution to which the aqueous solution was added was hermetically stored at 35 ° C., sampled at regular intervals, and cultured on a PY agar medium (pH 9), thereby measuring the number of bacteria in the coating solution.

[Comparative Examples 1-8]
As Comparative Examples 1 to 8, NaPT or MIT was used alone, and the other tests were performed in the same manner as in Examples. About Examples 1-16 in Table 3, the kind and density | concentration of the substance contained in an aqueous liquid agent, pH of an aqueous liquid agent, and the change of the number of bacteria in a coating liquid, Table 4 about aqueous solutions in Comparative Examples 1-8 The change of the kind and density | concentration of the substance contained in pH, the pH of an aqueous liquid agent, and the number of bacteria in a coating liquid is shown. In the table below, “blank” indicates the change in the number of bacteria for the untreated coating solution, the unit of the number of bacteria is the number of cells / ml, and the column indicated by “−” indicates that the growth of the number of bacteria is extremely unmeasured. Indicates that it is possible.

[Examples 17 to 26]
As Examples 17 to 26, instead of the circulating color coating liquid of the above example, the alkaline aqueous liquid agent used in the above example was added to the calcium carbonate slurry (pH 10.7) at a different concentration to perform the above. A test similar to the example was performed.

[Comparative Examples 9 to 18]
As Comparative Examples 9 to 18, the same tests as in Examples 17 to 26 were performed except that NaPT or MIT was used alone. Table 5 shows changes in Examples 17 to 26, and Table 6 shows Comparative Examples 9 to 18 in terms of the type and concentration of substances contained in the aqueous liquid, the pH of the aqueous liquid, and the number of bacteria in the coating liquid.

  As shown in Tables 3 to 6, in the example in which the aqueous liquid containing NaPT and MIT was added, the growth of microorganisms could be suppressed for a long period of time compared to the comparative example using NaPT or MIT alone. In particular, when added to a calcium carbonate slurry having a pH exceeding 10, it was shown that the antibacterial effect was exhibited over a long period of time even at a low concentration, compared to NaPT or MIT alone.

[Reference Examples 1 to 6]
In order to investigate the storage stability of the alkaline aqueous liquid preparation in which NaPT and MIT are dissolved in water, NaPT and MIT are mixed as Reference Examples 1 to 6 or dissolved in water alone, and sodium hydroxide is added. The pH was adjusted to 8.8 to 9.5. After storing this at 40 ° C. for 2 months, the concentration of NaPT and MIT contained in the aqueous liquid was measured using liquid chromatography. The results are shown in Table 7.

  As shown in Table 7, in the alkaline aqueous solution of Reference Example 2 in which MIT was dissolved alone in water, MIT was decomposed by nearly 30%, but in Reference Examples 3 to 6 in which NaPT coexisted, MIT was substantially reduced. The initial concentration was maintained without being decomposed.

  The present invention can be applied to an industrial antibacterial agent added to an alkaline liquid such as a papermaking coating solution.

It is a graph which shows the result of the performance test of the industrial antimicrobial composition of this invention. It is a graph which shows the result of the performance test of the industrial antimicrobial composition of this invention.

Claims (9)

  An industrial antibacterial composition comprising sodium pyrithione and 2-methyl-4-isothiazolin-3-one and added to an alkaline antibacterial target solution having a pH of 7 or higher.   An industrial antibacterial composition in which sodium pyrithione and 2-methyl-4-isothiazolin-3-one are dissolved in a solvent containing water to form an aqueous liquid having a pH of 7 or more.   The industrial antibacterial composition according to claim 1 or 2, having a pH of 9 to 11.   The industrial antibacterial composition according to any one of claims 1 to 3, wherein the sodium pyrithione and the 2-methyl-4-isothiazolin-3-one are contained in a weight ratio of 4: 1 to 1: 4. .   An antibacterial method of adding sodium pyrithione and 2-methyl-4-isothiazolin-3-one to an alkaline antibacterial solution having a pH of 7 or more.   The antibacterial method according to claim 5, wherein the sodium pyrithione and the 2-methyl-4-isothiazolin-3-one are dissolved in a solvent containing water and added to the alkaline antibacterial solution as an aqueous liquid having a pH of 7 or higher.   The antibacterial method according to claim 5, wherein the sodium pyrithione and the 2-methyl-4-isothiazolin-3-one are separately added to the alkaline antibacterial target liquid.   The antibacterial method according to any one of claims 5 to 7, wherein the alkaline antibacterial target liquid has a pH of 9 to 11.   The sodium pyrithione and the 2-methyl-4-isothiazolin-3-one are added to the alkaline antibacterial liquid at a weight ratio of 4: 1 to 1: 4, according to any one of claims 5 to 8. The antibacterial method described.

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