WO2001049119A1

WO2001049119A1 - A stabilized isothiazolone composition and a method of stabilization of isothiazolone

Info

Publication number: WO2001049119A1
Application number: PCT/KR2000/000526
Authority: WO
Inventors: Soon-Jong Hahn; Jin-Man Kim; Ki-Seung Choi; Seung-Hwan Kim; Jung-Ho Park; Jae-Min Ha; Gi-Bae Kim
Original assignee: Sk Chemicals Co., Ltd.
Priority date: 1999-12-31
Filing date: 2000-05-24
Publication date: 2001-07-12
Also published as: AU4622800A; EP1244358A4; EP1244358A1; JP2003519161A; CN1216532C; JP4621401B2; US6534076B1; DE60026292D1; ATE318517T1; KR100385714B1; EP1244358B1; CN1424874A; KR20000054080A

Abstract

The present invention relates to a stabilized isothiazolone composition and a method of stabilization of isothiazolone, more particularly, to a stabilized isothiazolone solution comprising (a) isothiazolone composition represented by formula (1), (b) sulfuric acid, and (c) solvent. Wherein, R1 and R2, which are the same or different, respectively represent a hydrogen atom; a halogen atom; or C1-C4 alkyl group; or R1 and R2 together form a cyclic allyl group; R3 represents C1-C10 alkyl group which is substituted or unsubstituted with a hydrogen atom, a halogen atom or hydroxy group; C2-C10 alkenyl group which is substituted or unsubstituted with a halogen atom; C2-C10 alkynyl group which is substituted or unsubstituted with a halogen atom; a halogen atom; C1-C10 alkyl group; or aralkyl group which is substituted or unsubstituted with C2-C9 alkoxy group.

Description

A STABILIZED ISOTHIAZOLONE COMPOSITION AND A METHOD OF STABILIZATION OF ISOTHIAZOLONE

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a stabilized isothiazolone

composition and a method of stabilization of isothiazolone, more particularly,

to a stabilized isothiazolone solution comprising (a) isothiazolone compound

represented by the following formula 1 , (b) sulfuric acid, and (c) solvent.

[formula 1]

Wherein,

R₁ and R₂, which may be the same or different, respectively

represent a hydrogen atom; a halogen atom; or C, ~ C₄ alkyl group; or R^

and R₂ together form cyclic allyl group;

R₃ represents a hydrogen atom; C, ~ C₁₀ alkyl group which is

substituted or unsubstituted with a halogen atom or hydroxy group; C₂ ~ C₁₀

alkenyl group which is substituted or unsubstituted with a halogen atom; C₂ ~ C₁₀ alkynyl group which is substituted or unsubstituted with a halogen atom;

C, ~ C₁₀ alkyl group; or aralkyl group which is substituted or unsubstituted

with C₂ ~ C₉alkoxy group.

The present invention also relates to a method of stabilization of

isothiazolone of the formula 1.

(b) Description of the Related Art

Since its development by Craw et al. in 1965, isothiazolone

compound has been extensively used in many industrial fields as a

disinfectant including an antibacterial and antimicrobial agent for dyes,

cosmetics, fibers, or plastics, etc.

However, since the isothiazolone compound is very unstable and

easily degraded by moisture in the air, heat and ultraviolet light, the

beneficial properties of the compound may be lost during storage. In order

to improve the stability of the isothiazolone compound, several methods

have been actively developed, and the typical method is to use a metal salt

stabilizer.

In U.S. Pat. Nos. 3,870,795 and 4,067,878, for example, metal nitrite

or metal nitrate are added to stabilize isothiazolone solutions. But such

metal salt stabilizers react with emulsion components in a latex emulsion to

produce precipitates. Further, in some cases, chlorine ions in the metal salt

may induce corrosion of the system and metal ions may increase the

hardness of water to induce scale. Thus, in such cases, the use of the metal salt is undesirable.

A preferred disinfectant should be stable during use, but should be

quickly degraded after use so as not to induce the secondary environmental

problem. Accordingly, there is a need for a stabilizer satisfying these

requirements.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a stabilized

isothiazolone solution that is useful as a disinfectant and antimicrobial agent,

has high stability and can contain active ingredient in high concentration.

It is another object of the present invention to provide a method of

stabilization of isothiazolone which can stabilize isothiazolone longer than

the conventional method using ferric salt, substantially prevents the

formation of nitrosamine and precipitates, substantially prevents heavy

metals from being discharged to the environment, substantially prevents ions

such as Mg²⁺ from binding to ions contained in the industrial water such as

P0₄ ^3', C0₃ ^2" to form a Hard Scale and does not use stabilizers comprising

ferric salts.

In order to achieve these object, the present invention provides a

stabilized isothiazolone composition comprising (a) isothiazolone compound

represented by the following formula 1 , (b) sulfuric acid, and (c) solvent. [formula 1]

Wherein,

R and R₂, which may be the same or different, respectively

represent a hydrogen atom; a halogen atom; or a C, ~ C₄ alkyl group; or R₁

and R₂ together form a cyclic allyl group;

R₃ represents a hydrogen atom; C, ~ C₁₀ alkyl group which is

alkenyl group which is substituted or unsubstituted with a halogen atom; C₂ ~

C₁₀ alkynyl group which is substituted or unsubstituted with a halogen atom;

C₁ ~ C₁₀ alkyl group; or aralkyl group which is substituted or unsubstituted

with C₂ ~ C₉alkoxy group.

The present invention also provides a method of stabilization of

isothiazolone comprising stabilizing isothiazolone by blending isothiazolone

and a stabilizer, wherein said isothiazolone is the compound represented by

the formula 1 , the stabilizer is sulfuric acid.

The present invention also provides a- method of sterilization of

bacteria and/or fungi and/or algae or suppression of the growth thereof comprising applying disinfectant compositions in the area that is

contaminated or contamination-vulnerable by bacteria and/or fungi and/or

algae, wherein said disinfectant compositions are the stabilized isothiazolone

solutions comprising (a) isothiazolone compound represented by the formula

1 , (b) sulfuric acid and (c) solvent.

DETAILED DESCRIPTION AND THE PREFERRED EMBODIMENTS

Upon having endeavored to solve the problem of the conventional

method of stabilization of isothiazolone, inventors of the present invention

found that, if sulfuric acid is added as stabilizers, the degradation of

isothiazolone can be prevented, and completed the present invention.

The stabilized isothiazolone solution of the present invention

comprises isothiazolone compound represented by the formula 1 , sulfuric

acid and solvent.

The isothiazolone compound which may be used in the present

invention includes one or more compounds selected from the group

represented by formula 1 , preferably one or more compounds selected from

the group consisting of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-

isothiazolin-3-one, 4,5-dichloro-2-methyl-4-isothiazolin-3-one, 5-chloro-2-n-

octyl-4-isothiazolin-3-one, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one and

benzoisothiazolin-3-one. It is more preferable to use 5-chloro-2-methyl-4-

isothiazolin-3-one or 4,5-dichloro-2-methyl-4-isothiazolin-3-one alone or a

mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-

3-one. When using a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one, the weight ratio is preferably about 50:50 ~

99:1 , more preferably about 60:40 ~ 95:5. In addition, it is also preferable to

use a mixture comprising 2-methyl-4-isothiazolin-3-one as an active

ingredient and a small amount of 5-chloro-2-methyl-4-isothiazolin-3-one. In

such case, the weight ratio is preferably about 99.5:0.5 ~ 90:10, more

preferably about 98:2 ~ 96:4.

The sulfuric acid used as stabilizer in the stabilized isothiazolone

solution of the present invention preferably has high purity..

The solvent contained in the stabilized isothiazolone solution can be

any type of solvent which can effectively disperse the isothiazolone

compound and sulfuric acid. Preferably the solvent is water. The amount

of solvent can be varied according to the use of the stabilized isothiazolone

solution. And, if the purpose is only storage, the solvent may not be used.

The stabilized isothiazolone solution according to the present

invention may be made in the form of concentrated solution or diluted

solution according to the purpose. When stabilized isothiazolone is

employed in exceptional cases such as mass shipments, more concentrated

solutions may be used. The isothiazolone solution comprises about

0.00001 ~ 99 wt % of one or more compounds selected from isothiazolone

represented by formula 1 , 0.00001 ~ 99 wt % of stabilizer, and less than

99.99998 wt % of solvent. Preferably, it comprises 0.1 - 40 wt % of one or

more compounds selected from isothiazolone represented by formula 1 , 0.1

~ 99 wt % of stabilizer, and 99.8 wt % or less of solvent. Most preferably, it comprises 1 ~ 30 wt % of one or more compounds selected from

isothiazolone represented by formula 1 , 5 ~ 99 wt % of stabilizer, and 94

wt % or less of solvent. Conventional isothiazolone solution using metal salt

stabilizer can contain at most 14 wt % of active ingredient isothiazolone,

while the stabilized isothiazolone solution of the present invention can

contain up to 40 wt % of isothiazolone.

The amount of stabilizer may vary according to the conditions of use

and the concentration of isothiazolone in a mixture; preferably, the weight

ratio of isothiazolone : stabilizer is in the range of 1 :0.01 ~ 1 :1 ,000. This

range is preferable in terms of stability and cost-saving. In the case of a

concentrated solution, the weight ratio of isothiazolone : stabilizer is

preferably in the range of 1 :0.02 ~ 1 :50. Even though more amount of

stabilizer may be used, this is uneconomical. In the case of an extremely

diluted isothiazolone solution (about 1 ~ 10,000 ppm of isothiazolone in

solvent), the weight ratio of isothiazolone : stabilizer is preferably in the

range of 1:0.1 ~ 1 :20, more preferably in the range of 1:0.1 ~ 1:10.

As aforementioned, the stabilized isothiazolone solution according to

the present invention is very stable in the air, its efficacy may be sustained

under a relatively prolonged period of time in storage, and it forms smaller

precipitates than the conventional isothiazolone solution using metal salt

stabilizer. Further, the stabilized isothiazolone solution according to the

present invention exhibits excellent antimicrobial activities when the effective

amount of the solution is applied to the area that is contaminated or contamination-vulnerable by microbes, and removes the hard scale forming

factor. In particular, it has the merit that it is dissolved quickly and does not

induce the secondary environmental problem when discharged.

In other words, the stabilized isothiazolone solution may be

extensively used in the following fields: germicidal agents, sanitary aids,

purifier, deodorizer, soap in the form of liquid or powder, anti-oil and anti-

greasing agents, chemical products for the treatment of foods, daily chemical

products, food protectives, protectives for animal feeds, wood protectives,

dyes, lazures, flavoring agents, medical preservatives including hospital,

metal agents, dyeing solutions, cooling water, air purifier, petroleum

manufacture, paper-treatment, anti-slime agent at a paper mill, petroleum

products, adhesives, fibers, paint slurry, latex, treatment for leather articles,

petroleum fuels, laundry disinfectants, blending feeds for farming, ink, mining,

non-woven fabric, petroleum reservoirs, paste material, rubber, sugar

refining, tobacco, swimming pool, cosmetics, commodities for toilet, pastes,

plastics, cardboard, pharmaceuticals, chemical toilet paper, household

laundries, additives for diesel fuel, wax, cork, lubricants, commodities for

construction, blending or polishing agents for concrete; it may also be used

in the area that is contaminated or contamination-vulnerable by bacteria,

fungi or algae and in the places containing organic materials and water

where undesirable microorganisms may grow.

The present invention is explained in more detail by the following

examples, but the claims are not limited to these examples. Isothiazolone solutions obtained from the following examples and

comparative example, were respectively left in a thermostat at 65 ^°C to

measure their thermal stabilities. The degree of degradation was measured

by high performance liquid chromatography (HPLC). The thermal stability

was measured at 65 ^°C . In general, the thermal stability measured at

65 ^°C during one week corresponds to that measured at 25 ^°C during 7

months.

[EXAMPLE 1]

Stabilized isothiazolone solution was prepared by blending 25 wt %

of an isothiazolone mixture comprising 5-chloro-2-methyl-4-isothiazolin-3-one

chlorate and 2-methyl-4-isothiazolin-3-one chlorate, 75 wt % of the aqueous

solution comprising 98 wt % sulfuric acid, without using metal salt stabilizer.

The presence of precipitates in the prepared solution was observed by

naked eye with the lapse of time. The results of residual contents(%) and

formed precipitates with the lapse of time are represented in the following

table 1.

[Table 1]

[EXAMPLE 2]

Stabilized isothiazolone solution was prepared by blending 25 wt %

of 4,5-dichloro-2-methyl-4-isothiazolin-3-one, 75 wt % of the aqueous

solution comprising 98 wt % sulfuric acid, without using metal salt stabilizer.

The presence of precipitates in the prepared solution was observed by

naked eye with the lapse of time. The results of residual contents(%) and

formed precipitates with the lapse of time are represented in the following

table 2.

[Table 2]

[EXAMPLE 3]

Stabilized isothiazolone solution was prepared by blending 25 wt %

of a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one chlorate and 2-methyl-

4-isothiazolin-3-one chlorate, 65 wt % of the aqueous solution comprising 98

wt % sulfuric acid, and 10 wt % of deionized water, without using metal salt

stabilizer. The results of residual contents(%) with the lapse of time are

represented in the following table 3. , [Table 3]

[EXAMPLE 4]

Stabilized isothiazolone solution was prepared by blending 25 wt %

of a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one chlorate and 2-methyl-

4-isothiazolin-3-one chlorate, 52 wt % of the aqueous solution comprising 98

wt % sulfuric acid, and 23 wt % of phosphoric acid, without using metal salt

stabilizer. The results of residual contents(%) with the lapse of time are

represented in the following table 4.

[Table 4]

[EXAMPLE 5]

In order to measure the stability of isothiazolone solution of high

concentration, isothiazolone solution was prepared by blending 32 wt % of a

mixture of 5-chloro-2-methyl-4-isothiazolin-3-one chlorate and 2-methyl-4-

isothiazolin-3-one chlorate, 68 wt % of the aqueous solution comprising 98

wt % sulfuric acid, without using metal salt stabilizer, and the presence of precipitates in the prepared solution was observed by naked eye with the

lapse of time. The results of active ingredient contents(wt %) and formed

precipitates with the lapse of time are represented in the following table 5.

[Table 5]

The data in table 5 indicates that the stabilized isothiazolone solution

is very stable despite of containing 18 wt % or more of active ingredient. In

table 5, the reason why the contents of the active ingredient between 14th

and 28th is higher than that in the beginning is that water is evaporated

because the stability test in this example is carried out in a thermostat at

65 TJ .

[EXAMPLE 6]

Isothiazolone solution was prepared by blending 2 wt % of a mixture

of 5-chloro-2-methyl-4-isothiazoline chlorate and 2-methyl-4-isothiazolin-3-

one chlorate, 2 wt % of the aqueous solution comprising 98 wt % sulfuric

acid, and 96 wt % of deionized water, without using metal salt stabilizer.

The results of residual contents(%) under 50 ^°C thermostable condition with

the lapse of time are represented in the following table 4. [Table 6]

[EXAMPLE 7]

Isothiazolone solution was prepared by blending 10 wt % of a mixture

of 5-chloro-2-methyl-4-isothiazoline chlorate and 2-methyl-4-isothiazolin-3-

one chlorate, 30 wt % of the aqueous solution comprising 98 wt % sulfuric

acid, and 60 wt % of deionized water, without using metal salt stabilizer.

The results of residual contents(%) under 50 ^°C thermostable condition with

the lapse of time are represented in the following table 7.

[Table 7]

Comparative Example

Isothiazolone solution was prepared by blending 14 wt % of an

isothiazolone mixture comprising 5-chloro-2-methyl-4-isothiazolin-3-one

chlorate and 2-methyl-4-isothiazolin-3-one chlorate in a weight ratio of 3:1

and 10 wt % of metal nitrate as stabilizer. The results of residual contents(%) with the lapse of time are represented in the following table 8.

[Table 8]

The data in tables 1 to 8 indicate that both the stabilized

isothiazolone solution of the present invention and the conventional

isothiazolone solution using metal salt stabilizer remain stable for a long

period. However, the conventional isothiazolone solution using metal salt

stabilizer can contain at most 14 wt % of active isothiazolone, while the

stabilized isothiazolone solution of the present invention may contain active

isothiazolone more than 18 wt % as shown in the example 5.

[Test 1] The test of dissociation

In order to measure the speed of dissociation of the stabilized

isothiazolone solution of the present invention in water, isothiazolone

solutions prepared in the example 1 and comparative example were

respectively poured into deionized water such that he concentrations of

active isothiazolone amount to 100 ppm, and the residual contents(ppm) with

the lapse of time were measured. The results were represented in the

following table 9. [Table 9]

The results in table 9 indicate that the stabilized isothiazolone

solution of the present invention was dissociated in water more rapidly than

isothiasolone solution using metal salt stabilizer. The above result means

that the isothiazolone solution of the present invention is less likely to induce

the environmental problem than that of comparative example, because its

medicinal efficacy sustains for a certain period of time and it dissociates

rapidly.

[Test 2] MIC test against microorganisms

In order to measure the effect of the stabilized isothiazolone solution

of the present invention, isothiazolone solutions prepared in the example 1

and comparative example were respectively poured into deionized water

such that the concentrations of active isothiazolone amount to 14 wt %, and

the test of MIC(minimum inhibitory concentration) against microorganism

was carried out. The results were represented in the following table 10.

MIC test was carried out in the following manner: Isothiazolone

solutions of the example 1 and comparative example were diluted by double

continue dilution method using 96 multi-well plates, then microorganisms

were added to a plate in concentration of 10,000 CFU/ml, plates were incubated at 30 ^°C for 48 hours, and the growth of microorganisms were

determined by naked eye on the basis of turbidity. The media used in this

test Tryptic Soy Broth(Difco Co.) for bacteria and Patato Dextrose

Broth(Difco Co) for fungi. The strains used in this test were Staphylococcus

aureus ATCC 6538, Escherichia coli ATCC 11229, Pseudomonas

aeruginasa ATCC 15442, Pseudomonas oleoverans ATCC 8062, Aspergillus

niger ATCC 9642, Rhizopus oryzae ATCC 10404, Pullularia pullulans ATCC

9384.

[Table 10]

The result of table 10 indicates that both the stabilized isothiazolone

solution of the present invention and the conventional isothiazolone solution

have excellent sterilizing effect against microorganism, and that the degrees

of the sterilization of both solutions are comparable.

As - explained- above, ..-the present, invention has the effects of stabilizing the active ingredient for a long term without forming precipitates in

contrast to the conventional metal salt stabilizer and, if necessary, preparing

a stabilized isothiazolone solution of high concentration. In addition, the

conventional metlal salt stabilizer may form nitrosamine in product by nitrite

ion derived from metal nitrate ion under acidic condition, while the present

invention can stabilize isothiazolone solution without using metal salt

stabilizer thereby preventing the formation of nitrosamine in product.

Further, since isothiazolone solution prepared in accordance with the

present invention does not contain metal ion, it prevents heavy metals such

as Cu²⁺ from being discharged to the environment, and prevents ions such

as Mg²⁺ from binding to the ions contained in the industrial water such as

PO₄ ^3", CO₃ ^2" to form Hard Scale. Thus isothiazolone solution of the present

invention does not induce secondary environmental pollution and is able to

be effectively used in the field of water treatment where a Hard Scale is a

serious problem.

Claims

WHAT IS CLAIMED IS:

1. A stabilized isothiazolone composition comprising (a)

isothiazolone compound represented by the following formula 1 , (b) sulfuric

acid, and (c) solvent.

[formula 1]

Wherein,

R., and R₂, which are the same or different, respectively represent a

hydrogen atom; a halogen atom; or C, ~ C₄ alkyl group; or R., and R₂

together form cyclic allyl group;

R₃ represents a hydrogen atom; C, ~ C₁₀ alkyl group which is

alkenyl group which is substituted or unsubstituted with a halogen atom; C₂ ~

with C₂ ~ C₉alkoxy group.

2. The stabilized isothiazolone composition according to claim

1 , wherein the isothiazolone compound is selected from the group consisting of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 4,5-

dichloro-2-methyl-4-isothiazolin-3-one, 5-chloro-2-n-octyl-4-isothiazolin-3-one,

4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, benzoisothiazolin-3-one and the

mixture thereof.

3. The stabilized isothiazolone composition according to claim

1 , wherein the isothiazolone compound is a mixture of 5-chloro-2-methyl-4-

isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one in the weight ratio of

50:50 - 99:1.

4. The stabilized isothiazolone composition according to claim

1 , wherein the isothiazolone composition comprises 0.1 - 40 wt % of one or

more compounds selected from isothiazolone represented by formula 1 , 0.1

- 99 wt % of stabilizer, and 99.8 wt % or less of solvent.

5. A method of stabilization of isothiazolone comprising

stabilizing isothiazolone by blending isothiazolone and a stabilizer, wherein

said isothiazolone is the compound represented by the formula 1 , the

stabilizer is sulfuric acid

[formula 1]

Wherein

R₁ and R₂, which are the same or different, respectively represent a

hydrogen atom; a halogen atom; or C, - C₄ alkyl group; or R₁ and R₂

together form cyclic allyl group;

5 R₃ represents a hydrogen atom; C₁ ~ C₁₀ alkyl group which is

substituted or unsubstituted with a halogen atom or hydroxy group; C₂ - C₁₀

alkenyl group which is substituted or unsubstituted with a halogen atom; C₂ -

10 with C₂ ~ C₉alkoxy group.

6. A method of stabilization of isothiazolone according to claim

5, wherein the isothiazolone compound is selected from the group consisting

of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 4,5-

15 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, benzoisothiazolin-3-one and the

mixture thereof.

7. A method of stabilization of isothiazolone according to claim

5, wherein the isothiazolone compound is a mixture of 5-chloro-2-methyl-4-

isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one in the weight ratio of

20 50:50 - 99:1.

8. A method of stabilization of isothiazolone according to claim

5, wherein the amount of the sulfuric acid is 0.01 ~ 1000 part by weight on

the basis of the weight of isothiazolone compound.

9. A method of sterilization of bacteria and/or fungi and/or algae

or suppression of the growth thereof comprising applying disinfectant

compositions in the area that is contaminated or contamination-vulnerable by

bacteria and/or fungi and/or algae, wherein said disinfectant compositions

comprise (a) isothiazolone compound represented by the formula 1 , (b)

sulfuric acid and (c) solvent.

[formula 1]

Wherein,

R₁ and R₂, which are the same or different, respectively represent a

hydrogen atom; a halogen atom; or C, - C₄ alkyl group; or R₁ and R₂ together

form a cyclic allyl group;

R₃ represents a C, - C₁₀ alkyl group which is substituted or

unsubstituted with a hydrogen atom, a halogen atom or hydroxy group; C₂ -

C₁₀ alkenyl group which is substituted or unsubstituted with a halogen atom;

C₂ - C₁₀ alkynyl group which is substituted or unsubstituted with a halogen

atom; a halogen atom; C, - C₁₀ alkyl group; or aralkyl group which is

substituted or unsubstituted with C₂ - C₉ alkoxy group.