Antimicrobial compositions and their use

Abstract: An antimicrobial composition is provided in which the skin irritation of isothiazolone type compound is decreased and the injection operation properties thereof is improved by forming it as an uniform solution. The composition contains isothiazolone type compound and a compound which decreases the skin irritation of the former in a molar ratio of 1:0.1-50 and is dissolved in a solvent.

Description: The present invention is related to a method of using an antimicrobial composition and, in particular, to a novel antimicrobial composition in which the skin irritation of the isothiazolone type compounds such as 5-chloro-2-methyl-4-isothiazoline-3-one (hereafter referred to as C1-MIT) is decreased and the handling properties thereof are improved by means of forming it in the solution form. The isothiazolone type compounds represented by C1-MIT having following formula have been widely used as slime control agent, bacteriocide, algicide, and fungicide for various systems such as cooling water system, paper mill system, paint, adhesive, cutting fluid, and night soil treatment system. However, the isothiazolone type compounds are known for its highly irritating nature to skin and consequently, great care was required in the handling of chemicals which include these compounds in the composition. As a means of solving these problems, it is proposed to form a solid form molecular compound (a compound in which two or more stable molecules combine with each other with an inter-molecular force such as hydrogen bond or van der Waals force, of which specific form includes clathrate compound and complex) from the isothiazolone type compound, and carboxylic acid, phenol, alcohol amide type compound so that the skin irritation of isothiazolone type compounds is decreased and that its stability is improved (Japanese patent applications JP 2-57046B, and JP 1-190602A, JP 7-69816A, JP 7-101890A, and JP 7-330520A). The forms in which the molecular compound is employed include using the molecular compound in powder form, or using the molecular compound powder after formed in tablets. In addition, it is proposed, for the purpose of improving the ease of control and operation properties at the addition of chemical, to disperse the molecular compound in dispersion media such as water or organic solvents, making it a liquid chemical (JP 1-31630A and JP 8-259410A). However, the liquid chemical comprising the aforementioned molecular compound had several problems such as: although the molecular compound is dispersed into fine particles, the uniformity is not sufficient to prevent clogging in injection pump or piping; it tends to solidity when cares are not taken to prevent it from drying; a special type pump is required to inject it due to its high viscosity because a viscosity improver is usually added to it to prevent particles from sedimentation. Therefore, a chemical having a decreased skin irritation and improved stability as well as an uniformity to enable an excellent injection operation properties has been needed. Database WPI Section Ch, Week 9343 Derwent Publications Ltd., London, GB: Class C02, AN 93-339711 XP002099351 & JP 05 247011 A disclose a cyclodextrine inclusion compound useful as a bactericide, containing an isothiazoline compound. EP-A-0332336 discloses an antimicrobial composition which comprises a clathate compound containing a water-soluble microbicide and a dispersion medium. US-A-5559083 discloses an aqueous solution comprising an isothiazolone compound mixed with a branched cyclodextrine. Database WPI Section Ch, Week 9204 Derwent Publications Ltd., London, GB: Class C02, AN 92-030653 XP002099353 & JP 03 279373 A discloses inclusion compounds containing a water-insoluble isothiazolone compound as a guest compound and a bisphenol-compound or a deoxycholic acid as a host compound. EP-A-0435439 discloses carboxyl stabilizers for 3-isothiazolones. EP-A-0895718 comprises part of the state of the art under the provisions of Article 54(3) and (4) EPC and discloses a complex of cyclodextrine with isothiazoline. It is an object of the present invention to provide a method of using an antimicrobial composition which overcomes the problems of the prior art as pointed out in the above, suppressing the skin irritation of the isothiazolone type compounds and improving the stability of the same, while improving the injection operation properties and stability in storage by means of forming the composition in the form of uniform solution. The present invention provides an antimicrobial method for the purpose of preventing slime in pulp and papermaking systems, the method comprising the step of adding an antimicrobial composition which contains one or more isothiazolone type compounds and a compound for decreasing skin irritation of said isothiazolone type compounds in a molar ratio of 1:0.1 - 1:50, and which is dissolved in a solvent for the one or more isothiazolone type compounds and for the compound for decreasing skin irritation, wherein the compound for decreasing the skin irritation of isothiazolone type compounds is selected from at least one of (a) carboxylic acids, (b) phenolic compounds, and (c) alcoholic compounds, wherein (a) the carboxylic acids are selected from 4-nitrobenzoic acid; 4-chloro-3-nitrobenzoic acid; 2-chloro-4-nitrobenzoic acid; 4-chloro-2-nitrobenzoic acid; 2,4-dinitrobenzoic acid; 4-nitrophthalic acid; 3,5-diiodosalicyclic acid; 3,5-dinitrosalicylic acid; genticinic acid (2,5-dihydroxybenzoic acid); protocatechuic acid (3,4-dihydroxybenzoic acid); or deoxycholic acid, wherein (b) the phenolic compounds are either those compounds represented by the following formulae (6), (7), and (8): in formula (6), R 6 and R 7 representing an alkyl group with 1-4 carbon atoms, in formula (7), R 8 representing an alkylidene group with 2-4 carbon atoms, a cyclohexylidene group, an S atom, or an SO 2 group, and R 9 , R 10 representing a hydrogen atom or a halogen atom, in formula (8), R 11 -R 18 representing a hydrogen atom, alkyl or alkoxy group with 1-3 carbon atoms, or a halogen atom, and R 19 representing a single bond, methylene group, ethylene group, or phenylene group; or selected from 2-5-di-t-butylhydroquinone; t-butylhydroquinone; 2,5-bis(2,4dimethylphenyl)hydroquinone; 2,4-dihydroxybenzophenone; 4,4'-dihydroxybenzophenone; 2,2',4,4'-tetrahydroxybenzophenone; 2-hydroxy-4-methoxybenzophenone; or 1,1'-bi-2-naphtol; and wherein (c) the alcoholic compounds are selected from 1,1,6-6,tetraphenyl-2,4-hexadiyne-1,6-diol; 1,6-bis(2-chlorophenyl)-1,6,diphenyl-2-4-hexadiyne-1,6-diol; 1,1-di(2,4-dimethylphenyl)-2-propyne-1-ol; 1,1,4,4-tetraphenyl-2-butyne-1,4-diol; 1,1,2,2,-tetraphenylethane-1,2-diol; 1,1,6,6-tetra(2,4-dimethylphenyl)-2,4-hexadiyne-1,6-diol; and α,α,α',α'-tetrapheynl-1,1'-biphenyl-2,2'-dimethanol; and wherein the solvent is water and/or at least one hydrophilic organic solvent selected from the group consisting of: dimethylformamide, ethyleneglycol, propyleneglycol, diethyleneglycol, dipropyleneglycol, methylcellosolve (ethyleneglycol monomethylether), phenylcellosolve, diethyleneglycol monomethylether, dipropyleneglycol monomethylether, alcohols with carbon atoms up to 8 except for octanol, methyl acetate, 2-ethyoxymethyl acetate, 2-ethoxyethyl acetate, and propylene carbonate, in such a way that the concentration of the one or more isothiazolone compounds in the system is from 0.1 to 25 g/m 3 . The present invention also provides an antiseptic method for systems selected from plastic emulsion, starch paste, starch slurry, paint and cutting oil for metals systems, the method comprising the step of adding an antimicrobial composition which contains one or more isothiazolone type compounds and a compound for decreasing skin irritation of said isothiazolone type compounds in a molar ratio of 1:0.1 - 1:50, and which is dissolved in a solvent for the one or more isothiazolone type compounds and for the compound for decreasing skin irritation, wherein the compound for decreasing the skin irritation of isothiazolone type compounds is selected from at least one of (a) carboxylic acids, (b) phenolic compounds, and (c) alcoholic compounds, wherein (a) the carboxylic acids are selected from 4-nitrobenzoic acid; 4-chloro-3-nitrobenzoic acid; 2-chloro-4-nitrobenzoic acid; 4-chloro-2-nitrobenzoic acid; 2,4-dinitrobenzoic acid; 4-nitrophthalic acid; 3,5-diiodosalicyclic acid; 3,5-dinitrosalicylic acid; genticinic acid (2,5-dihydroxybenzoic acid); protocatechuic acid (3,4-dihydroxybenzoic acid); or deoxycholic acid, wherein (b) the phenolic compounds are either those compounds represented by the following formulae (6), (7), and (8): in formula (6), R 6 and R 7 representing an alkyl group with 1-4 carbon atoms, in formula (7), R 8 representing an alkylidene group with 2-4 carbon atoms, a cyclohexylidene group, an S atom, or an SO 2 group, and R 9 , R 10 representing a hydrogen atom or a halogen atom, in formula (8), R 11 -R 18 representing a hydrogen atom, alkyl or alkoxy group with 1-3 carbon atoms, or a halogen atom, and R 19 representing a single bond, methylene group, ethylene group, or phenylene group; or selected from 2-5-di-t-butylhydroquinone; t-butylhydroquinone; 2,5-bis(2,4dimethylphenyl)hydroquinone; 2,4-dihydroxybenzophenone; 4,4'-dihydroxybenzophenone; 2,2',4,4'-tetrahydroxybenzophenone; 2-hydroxy-4-methoxybenzophenone; or 1,1'-bi-2-naphtol; and wherein (c) the alcoholic compounds are selected from 1,1,6-6,tetraphenyl-2,4-hexadiyne-1,6-diol; 1,6-bis(2-chlorophenyl)-1,6,diphenyl-2-4-hexadiyne-1,6-diol; 1,1-di(2,4-dimethylphenyl)-2-propyne-1-ol; 1,1,4,4-tetraphenyl-2-butyne-1,4-diol; 1,1,2,2,-tetraphenylethane-1,2-diol; 1,1,6,6-tetra(2,4-dimethylphenyl)-2,4-hexadiyne-1,6-diol; and α,α,α',α'-tetrapheynl-1,1'-biphenyl-2,2'-dimethanol; and wherein the solvent is water and/or at least one hydrophilic organic solvent selected from the group consisting of: dimethylformamide, ethyleneglycol, propyleneglycol, diethyleneglycol, dipropyleneglycol, methylcellosolve (ethyleneglycol monomethylether), phenylcellosolve, diethyleneglycol monomethylether, dipropyleneglycol monomethylether, alcohols with carbon atoms up to 8 except for octanol, methyl acetate, 2-ethyoxymethyl acetate, 2-ethoxyethyl acetate, and propylene carbonate, in such a way that the concentration of the one or more isothiazolone compounds in the system is from 1 to 5000 g/m 3 . The present invention further provides an antimicrobial composition which contains one or more isothiazolone type compounds and a compound for decreasing skin irritation of said isothiazolone type compounds in a molar ratio of 1:0.1 - 1:50, and which is dissolved in a hydrophilic organic solvent comprising propylene glycol, for the one or more isothiazolone type compounds and for the compound for decreasing skin irritation, wherein the compound for decreasing the skin irritation of isothiazolone type compounds is selected from at least one of (a) carboxylic acids, (b) phenolic compounds, and (c) alcoholic compounds, wherein (a) the carboxylic acids are selected from 4-nitrobenzoic acid; 4-chloro-3-nitrobenzoic acid; 2-chloro-4-nitrobenzoic acid; 4-chloro-2-nitrobenzoic acid; 2,4-dinitrobenzoic acid; 4-nitrophthalic acid; 3,5-diiodosalicyclic acid; 3,5-dinitrosalicylic acid; genticinic acid (2,5-dihydroxybenzoic acid); protocatechuic acid (3,4-dihydroxybenzoic acid); or deoxycholic acid, wherein (b) the phenolic compounds are either those compounds represented by the following formulae (6), (7), and (8): in formula (6), R 6 and R 7 representing an alkyl group with 1-4 carbon atoms, in formula (7), R 8 representing an alkylidene group with 2-4 carbon atoms, a cyclohexylidene group, an S atom, or an SO 2 group, and R 9 , R 10 representing a hydrogen atom or a halogen atom, in formula (8), R 11 -R 18 representing a hydrogen atom, alkyl or alkoxy group with 1-3 carbon atoms, or a halogen atom, and R 19 representing a single bond, methylene group, ethylene group, or phenylene group; or selected from 2-5-di-t-butylhydroquinone; t-butylhydroquinone; 2,5-bis(2,4dimethylphenyl)hydroquinone; 2,4-dihydroxybenzophenone; 4,4'-dihydroxybenzophenone; 2,2',4,4'-tetrahydroxybenzophenone; 2-hydroxy-4-methoxybenzophenone; or 1,1'-bi-2-naphtol; and wherein (c) the alcoholic compounds are selected from 1,1,6-6,tetraphenyl-2,4-hexadiyne-1,6-diol; 1,6-bis(2-chlorophenyl)-1,6,diphenyl-2-4-hexadiyne-1,6-diol; 1,1-di(2,4-dimethylphenyl)-2-propyne-1-ol; 1,1,4,4-tetraphenyl-2-butyne-1,4-diol; 1,1,2,2,-tetraphenylethane-1,2-diol; 1,1,6,6-tetra(2,4-dimethylphenyl)-2,4-hexadiyne-1,6-diol; and α,α,α',α'-tetrapheynl-1,1'-biphenyl-2,2'-dimethanol. In the antimicrobial composition of the method of the present invention, the compound which can decrease the skin irritation of the isothiazolone type compounds (hereafter it may be referred to as "skin irritation suppressor") is supposed to suppress the skin irritation by combining itself with the isothiazolone type compounds to form a molecular compound. This molecular compound shows a more drastic decrease in skin irritation in the solution state. The reason for this is supposed to be that the isothiazolone type compounds and the skin irritation suppressor have a relatively strong inter-molecular bond in the solution state and that the skin irritation suppressor masks the skin irritating portion in the structure of the isothiazolone type compounds to effect a decrease in skin irritation. In addition, since the antimicrobial composition of the present invention is in the solution state, the aforementioned problems in injecting a dispersion liquid are overcome and the stability in storage is also greatly improved. Preferably the isothiazolone type compounds in the composition of the present invention include one or more compounds represented by the following general formulas: (In the formulas (1) and (2) shown above, R, X, M, Z, a, and n represent the following, respectively: R: Hydrogen atom, alkyl group, alkenyl group, alkynyl group, or aralkyl group; X: Hydrogen atom or halogen atom; Y: Hydrogen atom or halogen atom; (X and Y may condense to form a benzene ring) M: Cationic atom or group selected from a group consisting of alkali metals, alkali earth metals, heavy metals, and amine; Z: anion atom or group having a solubility sufficiently high to form a complex with the cation M; a: An integral number 1 or 2; and n: An integral number with which an anion Z fills the valence of the cation M.) The isothiazolone type compounds include, for instance, such compounds represented by the structural formal (1) in the above as 5-chloro-2-methyl-4-isothiazoline-3-one(C1-MIT); 2-methyl-4-isothiazoline-3-one; 4,5-dichloro-2-methyl-4-isothiazoline-3-one; 2-ethyl-4-isothiazoline-3-one; 2-octyl-4-isothiazoline-3-one; 5-chloro-2-octyl-4-isothiazoline-3-one; 4,5-dichloro-2-octyl-4-isothaizoline-3-one; 1,2-benz0-isohtiazoline-3-one; and complex of these compounds with such salts as magnesium chloride, magnesium nitrate, copper chloride, copper nitrate, and calcium chloride. In the present invention, however, the isothiazolone type compounds which do not form complex with salts as shown in the formula (1) are preferred since they form molecular compounds more easily with the skin irritation suppressors in the solution and have a higher degree of skin irritation suppression. For the skin irritation suppressor, the one or more of the compounds required by the invention form a crystalline molecular compound with the isothiazolone type compounds, and so will form a strong inter-molecular bond also in the solution state. Specifically, the compounds represented by the general formula (6) include 2,4-di-t-butylphenol; and 2,4-dipropylphenol. The compounds represented by the general formula (7) include 2,2'-thio-bis(4-chlorophenol); 4,4-cyclohexylidenebisphenol; 4,4'-ethylidenebisphenol; and 4,4'-isobutylidenebisphenol. The compounds represented by the general formula (8) include 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane; 1,1,2,2-tetrakis(3-methyl-4-hydroxyphenyl)ethane; and 1,1,2,2-tetrakis(3-chloro-4-hydroxyphenyl)ethane. In the present invention, the concentration of the isothiazolone type compounds in the solution is preferably from 0.1 to 5% by weight in terms of practice. The skin irritation suppressor is used in a molar ratio to the isothiazolone type compounds of 1:0.1 - 1:50, and preferably 1:0.5 - 1:20, the number 1 being for the isothiazolone type compounds. The concentration of the skin irritation suppressor in the solution is preferably 0.1 - 20% by weight. In the present invention, in order to add other functions to the antimicrobial composition, the following additives under (a) - (e) can be combined. (a) Corrosion inhibitor: For example, tolyltriazole, benzotriazole, methylbenzotriazole, molybdic acid, tungstic acid, silicic acid, nitrous acid, 2-phosphonobutane-1,2,4-tricarbonic acid, hydroxyethylidenediphosphonic acid, hexamethaphosphoric acid, tripolyphosphoric acid, orthophosphoric acid, salts of acids above, zinc chloride, acidic zinc chloride, zinc sulfate, zinc ligninsulfonate, and hydrazine. (b) Scale inhibitor: For example, polyacryric acid, acrylic acid / hydroxyethylidene methacrylate copolymer, acrylic acid / hydroxyethylidene methacrylate / methyl acrylate copolymer, acrylic acid / allylglycidyl ethers copolymer, acrylic acid / 2-hydroxy-3-allyloxy-1-propanesulfonic acid copolymer, acrylic acid / isoprenesulfonic acid copolymer, acrylic acid / vinylsulfonic acid copolymer, acrylic acid / allylsulfonic acid copolymer, polymaleic acid, maleic acid or maleic anhydride / isobutylene copolymer, maleic acid or maleic anhydride / styrenesulfonic acid copolymer, maleic acid or maleic anhydride / acrylic acid copolymer, maleic acid or maleic anhydride / acrylate acid copolymer, maleic acid or maleic anhydride 2-acrylamide-2-methylpropanesulfonic acid copolymer, maleic acid or maleic anhydride / amylenic acid copolymer, maleic acid or maleic anhydride / allyl- substituted fluorescent substances (such as 5-allylbenzosuberenol) copolymer, polyacrylamide, polyithaconic acid, and salts of the above substances. (c) Other antimicrobial agents: For example, halogen- and nitro-substituted aliphatic alcohols (such as 2-bromo-2-nitro-1,3-propanediol; and 2,2-dibromo-2-nitroethanol) and their esters, 2,2-dibromo-3-nitrilopropionamide, alkylene bisthiocyanates (such as methylene bisthiocyanate); 1,4-bisbromoacethoxy-2-butene, hexabromodimethylsulfone, isophthalonitryle type compounds (such as 5-chloro-2,4,6-trifluoroisophthalonitryl and tetrachloroisphthalonitryl), dimethyldithiocarbamate; 4,5-dichloro-1,2-dithiol-3-one; 3,3,4,4-tetrachlorotetrahydrothiophene-1,1-dioxide; triiodoallyl alcohol; bromonitrostyrene; aldehyde compounds (such as gluthalaldehyde, phthalaldehyde, isophthalaldehyde, telephthalaldehyde); dichloroglyoxim; benzaldoxim type compounds (such as α-chlorobenzaldoxim acetate and -chlorobenzaldoxim); and 5,5-methylhydantoine. (d) Antifoaming agent: For example, silicone type or non-silicone type anti-foaming agents. (e) Algicides: For example, s-triazine type algicide. Additives are by no means limited to those cited in the above but the other additives can be also used. The antimicrobial composition of the present invention is prepared according to, for example, a formula in the following using the above mentioned additives. Isothiazolone type compound 0.1-5 Skin irritation suppressor 0.1-60 Corrosion inhibitor 0-50 Scale inhibitor 0-50 Antimicrobial agent 0-30 Antifoaming agent 0-10 Algicide agent 0-10 Solvent (Water, propylene glycol) 30-99 Thus prepared antimicrobial composition of the present invention is added to the systems so that a desired concentration of the isothiazolone type compounds is obtained in the system, which differs according to the purpose as follows: (i) Anti-slime purpose in a pulp and paper mill system or cooling water system, etc.: isothiazolone type compound concentration of 0.1-25 g/m 3 . (ii) Antiseptic purpose in plastic emulsion, starch paste, starch slurry, paint, cutting fluid for metals, etc: isothiazolone type compounds concentration of 0.1-5000 g/m 3 . Examples The present invention will now be described more specifically in the following by means of the examples and comparative examples, which, however, are not to limit the present invention. The isothiazolone type compounds and other antimicrobial agents used in the examples and comparative examples are as follows: [Chermicals containing isothiazolone type compounds] Zonen F: A chemical containing 14 weight % of a mixture of 5-chloro-2-methyl-4-isothiazoline-3-one (C1-MIT) and 2-methyl-4-isothiazoline-3-one (MIT) together with ethyleneglycol. Kathon WT : An aqueous solution containing 14 weight % of a mixture of C1-MIT and MIT together with magnesium chloride and magnesium nitrate. [Other chemical containing antimicrobial agent] Dibnirol A-75 : A chemical containing 75 weight % of 2.2-dibromo-2-nitroethanol (DBNE) together with diethyleneglycol. Example 1, Comparative Examples 1, 2 Chemicals were dissolved by stirring according to the compositions shown in Table 4 to prepare the antimicrobial compositions. Example 1 Comparative Example 1 Comparative Example 2 Isothiazolone type compound (Zonen F) 10 10 ― Skin irritation suppressor (EBP) 12 ― ― Solvent (Propyleneglycol) 64.6 76.6 86.6 Other antimicrobial agent (Dibnirol A-75) 13.4 13.4 13.4 The prepared antimicrobial compositions were subjected to a skin irritation screening test using each 3 white rabbits (New Zealand white breed). A portion of the normal skin of the rabbit was provided as the test portion which was covered for 4 hours with a gauze patch dipped with 0.5 ml of the non-diluted chemical. After 4 hours the patch was removed, the test portion was washed and the state of the test portion of the skin was observed and recorded at 1, 24, 48, and 72 hours after the washing, according to the following evaluation criteria. In addition, the evaluated score was averaged for 72 hours and indicated as skin primary irritation index (PII). The obtained results are shown in Table 2. -Evaluation criteria- Eryrhema formation: No erythema 0 Very light erythema (hardly discernible) 1 Clear erythema 2 Medium to high degree erythema 3 High degree erythema to slight skin formation 4 Edema formation: No edema 0 Very light edema (hardly discernible) 1 Light edema (clear bulge with discernible edge) 2 Medium edema (about 1 mm bulge) 3 High degree edema (about 1 mm bulge surpassing test portion) 4 The PII value in the example where EBP is combined together with C1-MIT, MIT and DBNE is 4.8, while the PII value in Comparative Example 1 is 8.0, indicating a very strong skin irritation. From this result, the effect of EBP to decrease the skin irritation is confirmed. Also, it has become clear that the skin irritation of the composition in which EBP is contained is decreased to the level of Comparative Example 2 where only DBNE is used. A test of antimicrobial activity was performed using the antimicrobial compositions of Example 1 and Comparative Example 1. Bacillus subtillus was inoculated on a liquid culture medium based on peptone-yeast extract (containing peptone 1 g/l and yeast extract 1g/l) so that a level of 10 6 bacteria/mL was attained. Then, the antimicrobial compositions of Example 1 and Comparative Example 2 were added respectively so that the C1-MIT concentrations shown in Table 3 were obtained. The growth inhibiting effect was checked after 24 hours of cultivation at 30 · under shaking. Example C1-MIT concentration in the medium (mg/L) Growth inhibiting effect Example 1 0.1 + 0.3 - 0.5 - Comparative Example 1 0.1 + 0.3 - 0.5 - The results of Table 3 clearly shows that the antimicrobial composition of Example 1 has an growth inhibition effect which is equivalent to the antimicrobial composition of Comparative Example 1. Examples 2-4, Comparative Examples 3, 4 Chemicals were dissolved by stirring according to the compositions shown in Table 4 to prepare the antimicrobial compositions. (Part in weight) Example Comparative Examples 2 3 4 3 4 Isothiazolone type compounds Zonen F 5 ― 5 5 ― Kathon WT ― 5 ― ― 5 Skin irritation suppressor (pyromellitic acid) 0.85 0.85 0.85 ― ― Solvent (water) 94.15 94.15 73.05 95 95 Others Benzotriazole ― ― 0.1 ― ― 2-bromo-2-nitro-1.3-propanediol ― ― 1.0 ― ― Aqueous solution of polymaleic acid type compound (50 weight %) ― ― 20 ― ― The prepared antimicrobial compositions were subjected to a skin irritation screening test in a similar way as in Example 1 to obtain the skin primary irritation index (PII), of which results are shown in Table 5. Examples Comparative Examples 2 3 4 3 4 Skin primary irritation index (PII) 3.1 5.6 2.6 6.8 6.9 The results of Table 5 clearly shows that the compositions of Examples 2-4 in which pyromellitic acid were combined can decrease the skin irritation in comparison to the composition of Comparative Example 3 containing no pyromellitic acid. It is also shown from the results of Example 2 and Example 3 that the irritation decreasing effect is greater in the composition in which the isochiazolone type compounds do not form a complex with magnesium salts. Example 5, Comparative Example 5 Chemicals were dissolved by stirring according to the compositions shown in Table 6 to prepare the antimicrobial compositions. (Part by weight) Example 5 Comparative Example 5 Isothiazolone type compound (4,5-dichloro-2-octyl-4-isothiazoline-3-one) 1 1 Skin irritation suppressor (4.4'-cyclohexilidenebisphenol) 1.5 ― Solvent (Propyleneglycol) 97.5 99 The prepared antimicrobial compositions were subjected to a skin irritation screening test in a similar way as in Example 1 to obtain the skin primary irritation index (PII), of which results are shown in Table 7. Example 5 Comparative Example 5 Skin primary irritation index (PII) 5.0 7.8 The results of Table 7 clearly shows that the composition of Example 5 in which 4,4'-cyclohexilidenebisphenol was combined can decrease the skin irritation in comparison to the composition of Comparative Example 5 which does not contain 4,4'-cyclohexilidenebisphenol. Examples 6, 7 Chemicals were dissolved by stirring according to the composition shown in Table 8 to prepare the antimicrobial compositions. (Part by weight) Example 6 7 Isothiazolone type compounds Zonen F 5 5 Skin irritation suppressor Oxalic acid (dihydrate) 0.5 ― Trimellitic acid ― 1.9 Solvent (water) 73.4 72.0 Others Benzotriazole 0.1 0,1 2-bromo-2-nitro-1,8-propanediol 1.0 1.0 Aqueous solution of polymaleic acid type compound (50 weight %) 20 20 The prepared antimicrobial compositions were subjected to a skin irritation screening test in a similar way as in Example 1 to obtain the skin primary irritation index (PII), of which results are shown in Table 9. Example 6 7 Skin primary irritation index (PII) 3.7 4.0 The results of Table 9 shows an excellent skin irritation decreasing effect of the compositions 6 and 7 in which oxalic acid or trimellitic acid is combined, respectively. As is described in detail in the above, the microbial composition of the present invention is a solution type chemical in which the isothiazolone type compounds and those compounds which can form molecular compound therewith are combined. This composition can substantially decrease the skin irritation of the isothiazolone type compounds as a result of molecular compound formation and also by way of assuming the solution form. Since this composition is a solution, it offers no limitation to the injection pump, thus improving the handling and operation properties. In addition, the fact that the isothiazolone type compounds forms intermolecular bond with skin irritation suppressor even in the solution state prevents the isothiazolone type compounds from reacting with the other compounds causing deterioration in the antimicrobial activity .

Claims: An antimicrobial method for the purpose of preventing slime in pulp and papermaking systems, the method comprising the step of adding an antimicrobial composition which contains one or more isothiazolone type compounds and a compound for decreasing skin irritation of said isothiazolone type compounds in a molar ratio of 1:0.1 - 1:50, and which is dissolved in a solvent for the one or more isothiazolone type compounds and for the compound for decreasing skin irritation, wherein the compound for decreasing the skin irritation of isothiazolone type compounds is selected from at least one of (a) carboxylic acids, (b) phenolic compounds, and (c) alcoholic compounds, wherein (a) the carboxylic acids are selected from 4-nitrobenzoic acid; 4-chloro-3-nitrobenzoic acid; 2-chloro-4-nitrobenzoic acid; 4-chloro-2-nitrobenzoic acid; 2,4-dinitrobenzoic acid; 4-nitrophthalic acid; 3,5-diiodosalicyclic acid; 3,5-dinitrosalicylic acid; genticinic acid (2,5-dihydroxybenzoic acid); protocatechuic acid (3,4-dihydroxybenzoic acid); or deoxycholic acid, wherein (b) the phenolic compounds are either those compounds represented by the following formulae (6), (7), and (8): in formula (6), R 6 and R 7 representing an alkyl group with 1-4 carbon atoms, in formula (7), R 8 representing an alkylidene group with 2-4 carbon atoms, a cyclohexylidene group, an S atom, or an SO 2 group, and R 9 , R 10 representing a hydrogen atom or a halogen atom, in formula (8), R 11 -R 18 representing a hydrogen atom, alkyl or alkoxy group with 1-3 carbon atoms, or a halogen atom, and R 19 representing a single bond, methylene group, ethylene group, or phenylene group; or selected from 2-5-di-t-butylhydroquinone; t-butylhydroquinone; 2,5-bis(2,4dimethylphenyl)hydroquinone; 2,4-dihydroxybenzophenone; 4,4'-dihydroxybenzophenone; 2,2',4,4'-tetrahydroxybenzophenone; 2-hydroxy-4-methoxybenzophenone; or 1,1'-bi-2-naphtol; and wherein (c) the alcoholic compounds are selected from 1,1,6-6,tetraphenyl-2,4-hexadiyne-1,6-diol; 1,6-bis(2-chlorophenyl)-1,6,diphenyl-2-4-hexadiyne-1,6-diol; 1,1-di(2,4-dimethylphenyl)-2-propyne-1-ol; 1,1,4,4-tetraphenyl-2-butyne-1,4-diol; 1,1,2,2,-tetraphenylethane-1,2-diol; 1,1,6,6-tetra(2,4-dimethylphenyl)-2,4-hexadiyne-1,6-diol; and α,α,α',α'-tetrapheynl-1,1'-biphenyl-2,2'-dimethanol; and wherein the solvent is water and/or at least one hydrophilic organic solvent selected from the group consisting of: dimethylformamide, ethyleneglycol, propyleneglycol, diethyleneglycol, dipropyleneglycol, methylcellosolve (ethyleneglycol monomethylether), phenylcellosolve, diethyleneglycol monomethylether, dipropyleneglycol monomethylether, alcohols with carbon atoms up to 8 except for octanol, methyl acetate, 2-ethyoxymethyl acetate, 2-ethoxyethyl acetate, and propylene carbonate, in such a way that the concentration of the one or more isothiazolone compounds in the system is from 0.1 to 25 g/m 3 . The method of claim 1, wherein the isothiazolone type compounds are one or more compounds selected from the group consisting of the compounds represented by the following formulae (1) and (2): in formulae (1) and (2) shown above, R, X, M, Z, a, and n representing the following respectively: R: Hydrogen atom, alkyl group, alkenyl group, alkynyl group, or aralkyl group; X: Hydrogen atom or halogen atom; Y: Hydrogen atom or halogen atom; and wherein X and Y may condense to form a benzene ring; M: Cationic atom or group selected from a group consisting of alkali metals, alkali earth metals, heavy metals, and amine; Z: Anion atom or group having a solubility sufficiently high to form a complex with the cation M; a: An integral number 1 or 2; and n: An integral number with which an anion Z fills the valence of the cation M. The method of claim 2, wherein the isothiazolone type compounds are one or more compounds selected from the group consisting of: 5-chloro-2-methyl-4-isothiazoline-3-one (C1-MIT); 2-methyl-4-isothiazoline-3-one; 4,5-dichloro-2-methyl-4-isothiazoline-3-one; 2-ethyl-4-isothiazoline-3-one; 2-octyl-4-isothiazoline-3-one; 5-chloro-2-octyl-4-isothiazoline-3-one; 4,5-dichloro-2-octyl-4-isothiazoline-3-one; and 1,2-benzo-isothiazoline-3-one. The method of any one of claims 1 to 3, wherein the phenolic compounds are selected from: 2,4-di-t-butylphenol; 2,4-dipropylphenol; 2,2'-thio-bis(4-chlorophenol); 4,4-cyclohexylidenebisphenol; 4,4'-ethylidenebisphenol; 4,4'-isobutylidenebisphenol; 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane; 1,1,2,2-tetrakis(3-methyl-4-hydroxyphenyl)ethane; or 1,1,2,2-tetrakis(3-chloro-4-hydroxyphenyl)ethane. The method of claim 1, wherein the concentration of the isothiazolone type compounds in the solution is from 0.1 to 5 weight %. The method of claim 1, wherein the isothiazolone type compound and the compound which decreases the skin irritation of the isothiazolone type compound are contained in a molar ratio of 1:0.5 - 1:20 and wherein the concentration of the compound which decreases the skin irritation of the isothiazolone type compound is from 0.1 to 20 weight %. The method of claim 1, wherein the composition further contains one or more components selected from the group consisting of corrosion inhibitors, scale inhibitors, antimicrobial agents other than isothiazolone type compounds, antifoaming agents, and algicides. The method of claim 7, wherein the composition is prepared according to the following formula in % by weight: Isothiazolone type compound 0.1-5 Skin irritation suppressor 0.1-60 Corrosion inhibitor 0-50 Scale inhibitor 0-50 Antimicrobial agent 0-30 Antifoaming agent 0-10 Algicide 0-10 Solvent 30-99 The method of claim 1, wherein the isothiazolone type compound and 4,4'-ethylidenebisphenol are dissolved in a hydrophilic solvent in which the concentration of isothiazolone type compound is 0.1 to 5 wt% and the molar ratio of 4,4'-ethylidenebisphenol to the isothiazolone type compound is 1:0.5 to 1:20, the number 1 being for the isothiazolone type compound. The method of claim 1, wherein the isothiazolone type compound and 4,4-cyclohexylidenebisphenol are dissolved in a hydrophilic solvent in which the concentration of isothiazolone type compound is 0.1 to 5 wt% and the molar ratio of 4,4-cyclohexylidenebisphenol to the isothiazolone type compound is 1:05 to 1:20, the number 1 being for the isothiazolone type compound. The method of claim 1, wherein the isothiazolone type compound and oxalic acid are dissolved in a hydrophilic solvent or water in which the concentration of isothiazolone type compound is 0.1 to 5 wt% and the molar ratio of oxalic acid to the isothiazolone type compound is 1:0.5 to 1:20, the number 1 being for the isothiazolone type compound, and at least one of a corrosion inhibitor, a scale inhibitor, an antimicrobial agent other than the isothiazolone type compound, an antifoaming agent and an algicide is further dissolved therein. The method of claim 1, wherein the isothiazolone type compound and pyromellitic acid are dissolved in a hydrophilic solvent or water in which the concentration of isothiazolone type compound is 0.1 to 5 wt% and the molar ratio of pyromellitic acid to the isothiazolone type compound is 1:0.5 to 1:20, the number 1 being for the isothiazolone type compound, and at least one of a corrosion inhibitor, a scale inhibitor, an antimicrobial agent other than the isothiazolone type compound, an antifoaming agent and an algicide is further dissolved therein. An antiseptic method for systems selected from plastic emulsion, starch paste, starch slurry, paint and cutting oil for metals systems, the method comprising the step of adding an antimicrobial composition which contains one or more isothiazolone type compounds and a compound for decreasing skin irritation of said isothiazolone type compounds in a molar ratio of 1:0.1 - 1:50, and which is dissolved in a solvent for the one or more isothiazolone type compounds and for the compound for decreasing skin irritation, wherein the compound for decreasing the skin irritation of isothiazolone type compounds is selected from at least one of (a) carboxylic acids, (b) phenolic compounds, and (c) alcoholic compounds, wherein (a) the carboxylic acids are selected from 4-nitrobenzoic acid; 4-chloro-3-nitrobenzoic acid; 2-chloro-4-nitrobenzoic acid; 4-chloro-2-nitrobenzoic acid; 2,4-dinitrobenzoic acid; 4-nitrophthalic acid; 3,5-diiodosalicyclic acid; 3,5-dinitrosalicylic acid; genticinic acid (2,5-dihydroxybenzoic acid); protocatechuic acid (3,4-dihydroxybenzoic acid); or deoxycholic acid, wherein (b) the phenolic compounds are either those compounds represented by the following formulae (6), (7), and (8): in formula (6), R 6 and R 7 representing an alkyl group with 1-4 carbon atoms, in formula (7), R 8 representing an alkylidene group with 2-4 carbon atoms, a cyclohexylidene group, an S atom, or an SO 2 group, and R 9 , R 10 representing a hydrogen atom or a halogen atom, in formula (8), R 11 -R 18 representing a hydrogen atom, alkyl or alkoxy group with 1-3 carbon atoms, or a halogen atom, and R 19 representing a single bond, methylene group, ethylene group, or phenylene group; or selected from 2-5-di-t-butylhydroquinone; t-butylhydroquinone; 2,5-bis(2,4dimethylphenyl)hydroquinone; 2,4-dihydroxybenzophenone; 4,4'-dihydroxybenzophenone; 2,2',4,4'-tetrahydroxybenzophenone; 2-hydroxy-4-methoxybenzophenone; or 1,1'-bi-2-naphtol; and wherein (c) the alcoholic compounds are selected from 1,1,6-6,tetraphenyl-2,4-hexadiyne-1,6-diol; 1,6-bis(2-chlorophenyl)-1,6,diphenyl-2-4-hexadiyne-1,6-diol; 1,1-di(2,4-dimethylphenyl)-2-propyne-1-ol; 1,1,4,4-tetraphenyl-2-butyne-1,4-diol; 1,1,2,2,-tetraphenylethane-1,2-diol; 1,1,6,6-tetra(2,4-dimethylphenyl)-2,4-hexadiyne-1,6-diol; and α,α,α',α'-tetrapheynl-1,1'-biphenyl-2,2'-dimethanol; and wherein the solvent is water and/or at least one hydrophilic organic solvent selected from the group consisting of: dimethylformamide, ethyleneglycol, propyleneglycol, diethyleneglycol, dipropyleneglycol, methylcellosolve (ethyleneglycol monomethylether), phenylcellosolve, diethyleneglycol monomethylether, dipropyleneglycol monomethylether, alcohols with carbon atoms up to 8 except for octanol, methyl acetate, 2-ethyoxymethyl acetate, 2-ethoxyethyl acetate, and propylene carbonate, in such a way that the concentration of the one or more isothiazolone compounds in the system is from 1 to 5000 g/m 3 . The method of claim 13, wherein the isothiazolone type compounds are one or more compounds selected from the group consisting of the compounds represented by the following formulae (1) and (2): in formulae (1) and (2) shown above, R, X, M, Z, a, and n representing the following respectively: R: Hydrogen atom, alkyl group, alkenyl group, alkynyl group, or aralkyl group; X: Hydrogen atom or halogen atom; Y: Hydrogen atom or halogen atom; and wherein X and Y may condense to form a benzene ring; M: Cationic atom or group selected from a group consisting of alkali metals, alkali earth metals, heavy metals, and amine; Z: Anion atom or group having a solubility sufficiently high to form a complex with the cation M; a: An integral number 1 or 2; and n: An integral number with which an anion Z fills the valence of the cation M. The method of claim 14, wherein the isothiazolone type compounds are one or more compounds selected from the group consisting of: 5-chloro-2-methyl-4-isothiazoline-3-one (C1-MIT); 2-methyl-4-isothiazoline-3-one; 4,5-dichloro-2-methyl-4-isothiazoline-3-one; 2-ethyl-4-isothiazoline-3-one; 2-octyl-4-isothiazoline-3-one; 5-chloro-2-octyl-4-isothiazoline-3-one; 4,5-dichloro-2-octyl-4-isothiazoline-3-one; and 1,2-benzo-isothiazoline-3-one. The method of any one of claims 13 to 15, wherein the phenolic compounds are selected from: 2,4-di-t-butylphenol; 2,4-dipropylphenol; 2,2'-thio-bis(4-chlorophenol); 4,4-cyclohexylidenebisphenol; 4,4'-ethylidenebisphenol; 4,4'-isobutylidenebisphenol; 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane; 1,1,2,2-tetrakis(3-methyl-4-hydroxyphenyl)ethane; or 1,1,2,2-tetrakis(3-chloro-4-hydroxyphenyl)ethane. The method of claim 13, wherein the concentration of the isothiazolone type compounds in the solution is from 0.1 to 5 weight %. The method of claim 13, wherein the isothiazolone type compound and the compound which decreases the skin irritation of the isothiazolone type compound are contained in a molar ratio of 1:0.5 - 1:20 and wherein the concentration of the compound which decreases the skin irritation of the isothiazolone type compound is from 0.1 to 20 weight %. The method of claim 13, wherein the composition further contains one or more components selected from the group consisting of corrosion inhibitors, scale inhibitors, antimicrobial agents other than isothiazolone type compounds, antifoaming agents, and algicides. The method of claim 19, wherein the composition is prepared according to the following formula in % by weight: Isothiazolone type compound 0.1-5 Skin irritation suppressor 0.1-60 Corrosion inhibitor 0-50 Scale inhibitor 0-50 Antimicrobial agent 0-30 Antifoaming agent 0-10 Algicide 0-10 Solvent 30-99 The method of claim 13, wherein the isothiazolone type compound and 4,4'-ethylidenebisphenol are dissolved in a hydrophilic solvent in which the concentration of isothiazolone type compound is 0.1 to 5 wt% and the molar ratio of 4,4'-ethylidenebisphenol to the isothiazolone type compound is 1:0.5 to 1:20, the number 1 being for the isothiazolone type compound. The method of claim 13, wherein the isothiazolone type compound and 4,4-cyclohexylidenebisphenol are dissolved in a hydrophilic solvent in which the concentration of isothiazolone type compound is 0.1 to 5 wt% and the molar ratio of 4,4-cyclohexylidenebisphenol to the isothiazolone type compound is 1:05 to 1:20, the number 1 being for the isothiazolone type compound. The method of claim 13, wherein the isothiazolone type compound and oxalic acid are dissolved in a hydrophilic solvent or water in which the concentration of isothiazolone type compound is 0.1 to 5 wt% and the molar ratio of oxalic acid to the isothiazolone type compound is 1:0.5 to 1:20, the number 1 being for the isothiazolone type compound, and at least one of a corrosion inhibitor, a scale inhibitor, an antimicrobial agent other than the isothiazolone type compound, an antifoaming agent and an algicide is further dissolved therein. The method of claim 13, wherein the isothiazolone type compound and pyromellitic acid are dissolved in a hydrophilic solvent or water in which the concentration of isothiazolone type compound is 0.1 to 5 wt% and the molar ratio of pyromellitic acid to the isothiazolone type compound is 1:0.5 to 1:20, the number 1 being for the isothiazolone type compound, and at least one of a corrosion inhibitor, a scale inhibitor, an antimicrobial agent other than the isothiazolone type compound, an antifoaming agent and an algicide is further dissolved therein. An antimicrobial composition which contains one or more isothiazolone type compounds and a compound for decreasing skin irritation of said isothiazolone type compounds in a molar ratio of 1:0.1 - 1:50, and which is dissolved in a hydrophilic organic solvent comprising propylene glycol, for the one or more isothiazolone type compounds and for the compound for decreasing skin irritation, wherein the compound for decreasing the skin irritation of isothiazolone type compounds is selected from at least one of (a) carboxylic acids, (b) phenolic compounds, and (c) alcoholic compounds, wherein (a) the carboxylic acids are selected from 4-nitrobenzoic acid; 4-chloro-3-nitrobenzoic acid; 2-chloro-4-nitrobenzoic acid; 4-chloro-2-nitrobenzoic acid; 2,4-dinitrobenzoic acid; 4-nitrophthalic acid; 3,5-diiodosalicyclic acid; 3,5-dinitrosalicylic acid; genticinic acid (2,5-dihydroxybenzoic acid); protocatechuic acid (3,4-dihydroxybenzoic acid); or deoxycholic acid, wherein (b) the phenolic compounds are either those compounds represented by the following formulae (6), (7), and (8): in formula (6), R 6 and R 7 representing an alkyl group with 1-4 carbon atoms, in formula (7), R 8 representing an alkylidene group with 2-4 carbon atoms, a cyclohexylidene group, an S atom, or an SO 2 group, and R 9 , R 10 representing a hydrogen atom or a halogen atom, in formula (8), R 11 -R 18 representing a hydrogen atom, alkyl or alkoxy group with 1-3 carbon atoms, or a halogen atom, and R 19 representing a single bond, methylene group, ethylene group, or phenylene group; or selected from 2-5-di-t-butylhydroquinone; t-butylhydroquinone; 2,5-bis(2,4dimethylphenyl)hydroquinone; 2,4-dihydroxybenzophenone; 4,4'-dihydroxybenzophenone; 2,2',4,4'-tetrahydroxybenzophenone; 2-hydroxy-4-methoxybenzophenone; or 1,1'-bi-2-naphtol; and wherein (c) the alcoholic compounds are selected from 1,1,6-6,tetraphenyl-2,4-hexadiyne-1,6-diol; 1,6-bis(2-chlorophenyl)-1,6,diphenyl-2-4-hexadiyne-1,6-diol; 1,1-di(2,4-dimethylphenyl)-2-propyne-1-ol; 1,1,4,4-tetraphenyl-2-butyne-1,4-diol; 1,1,2,2,-tetraphenylethane-1,2-diol; 1,1,6,6-tetra(2,4-dimethylphenyl)-2,4-hexadiyne-1,6-diol; and a,a,a',a'-tetrapheynl-1,1'-biphenyl-2,2'-dimethanol. The composition of claim 25, wherein the isothiazolone type compounds are one or more compounds selected from the group consisting of the compounds represented by the following formulae (1) and (2): in formulae (1) and (2) shown above, R, X, M, Z, a, and n representing the following respectively: R: Hydrogen atom, alkyl group, alkenyl group, alkynyl group, or aralkyl group; X: Hydrogen atom or halogen atom; Y: Hydrogen atom or halogen atom; and wherein X and Y may condense to form a benzene ring; M: Cationic atom or group selected from a group consisting of alkali metals, alkali earth metals, heavy metals, and amine; Z: Anion atom or group having a solubility sufficiently high to form a complex with the cation M; a: An integral number 1 or 2; and n: An integral number with which an anion Z fills the valence of the cation M. The composition of claim 26, wherein the isothiazolone type compounds are one or more compounds selected from the group consisting of: 5-chloro-2-methyl-4-isothiazoline-3-one (C1-MIT); 2-methyl-4-isothiazoline-3-one; 4,5-dichloro-2-methyl-4-isothiazoline-3-one; 2-ethyl-4-isothiazoline-3-one; 2-octyl-4-isothiazoline-3-one; 5-chloro-2-octyl-4-isothiazoline-3-one; 4,5-dichloro-2-octyl-4-isothiazoline-3-one; and 1,2-benzo-isothiazoline-3-one. The composition of any one of claims 25 to 27, wherein the phenolic compounds are selected from: 2,4-di-t-butylphenol; 2,4-dipropylphenol; 2,2'-thio-bis(4-chlorophenol); 4,4-cyclohexylidenebisphenol; 4,4'-ethylidenebisphenol; 4,4'-isobutylidenebisphenol; 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane; 1,1,2,2-tetrakis(3-methyl-4-hydroxyphenyl)ethane; or 1,1,2,2-tetrakis(3-chloro-4-hydroxyphenyl)ethane. The composition of claim 25, wherein the concentration of the isothiazolone type compounds in the solution is from 0.1 to 5 weight %. The composition of claim 25, wherein the isothiazolone type compound and the compound which decreases the skin irritation of the isothiazolone type compound are contained in a molar ratio of 1:0.5 - 1:20 and wherein the concentration of the compound which decreases the skin irritation of the isothiazolone type compound is from 0.1 to 20 weight %. The composition of claim 25, wherein the composition further contains one or more components selected from the group consisting of corrosion inhibitors, scale inhibitors, antimicrobial agents other than isothiazolone type compounds, antifoaming agents, and algicides. The composition of claim 31, wherein the composition is prepared according to the following formula in % by weight: Isothiazolone type compound 0.1-5 Skin irritation suppressor 0.1-60 Corrosion inhibitor 0-50 Scale inhibitor 0-50 Antimicrobial agent 0-30 Antifoaming agent 0-10 Algicide 0-10 Solvent 30-99 The composition of claim 25, wherein the isothiazolone type compound and 4,4'-ethylidenebisphenol are dissolved in the propylene glycol solvent in which the concentration of isothiazolone type compound is 0.1 to 5 wt% and the molar ratio of 4,4'-ethylidenebisphenol to the isothiazolone type compound is 1:0.5 to 1:20, the number 1 being for the isothiazolone type compound. The composition of claim 25, wherein the isothiazolone type compound and 4,4-cyclohexylidenebisphenol are dissolved in the propylene glycol solvent in which the concentration of isothiazolone type compound is 0.1 to 5 wt% and the molar ratio of 4,4-cyclohexylidenebisphenol to the isothiazolone type compound is 1:05 to 1:20, the number 1 being for the isothiazolone type compound. The composition of claim 25, wherein the isothiazolone type compound and oxalic acid are dissolved in the propylene glycol solvent in which the concentration of isothiazolone type compound is 0.1 to 5 wt% and the molar ratio of oxalic acid to the isothiazolone type compound is 1:0.5 to 1:20, the number 1 being for the isothiazolone type compound, and at least one of a corrosion inhibitor, a scale inhibitor, an antimicrobial agent other than the isothiazolone type compound, an antifoaming agent and an algicide is further dissolved therein. The composition of claim 25, wherein the isothiazolone type compound and pyromellitic acid are dissolved in the propylene glycol solvent in which the concentration of isothiazolone type compound is 0.1 to 5 wt% and the molar ratio of pyromellitic acid to the isothiazolone type compound is 1:0.5 to 1:20, the number 1 being for the isothiazolone type compound, and at least one of a corrosion inhibitor, a scale inhibitor, an antimicrobial agent other than the isothiazolone type compound, an antifoaming agent and an algicide is further dissolved therein.

Inventors: AOKI TETSUYA, YAGI MINORU, AOKI, TETSUYA, YAGI, MINORU, AOKI, TETSUYA, KURITA WATER INDUSTRIES LTD., YAGI, MINORU, KURITA WATER INDUSTRIES LTD.
Applicants: KURITA WATER IND LTD, KURITA WATER INDUSTRIES LTD.
Application year: 1998
Main classification: A01N43
IPC codes: A01N25, A01N43