Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Biocides; animal or insect repellents or attractants
Reexamination Certificate
2000-06-05
2003-03-18
Levy, Neil S. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Biocides; animal or insect repellents or attractants
C504S156000, C514S372000, C548S213000, C510S383000
Reexamination Certificate
active
06534076
ABSTRACT:
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) an isothiazolone compound of formula I, (b) sulfuric acid, and (c) solvent.
where
R
1
and R
2
each independently represent a hydrogen atom, a halogen atom, or C
1
-C
4
alkyl group, or R
1
and R
2
together form a cyclic allyl group;
R
3
represents a hydrogen atom; C
1
-C
10
alkyl group which is substituted or unsubstituted with a halogen atom or hydroxy group, C
2
-C
10
alkenyl group which is substituted or unsubstituted with a halogen atom, C
2
-C
10
alkynyl group which is substituted or unsubstituted with a halogen atom, C
1
-C
10
alkyl group, or aralkyl group which is substituted or unsubstituted with C
2
-C
9
alkoxy group.
The present invention also relates to a method of stabilization of isothiazolone of the formula I.
(b) Description of the Related Art
Since development by Craw et al. in 1965, isothiazolone compounds have 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 isothiazolone 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 isothiazolone, 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 cause a persistent environmental problem. Accordingly, there is a need for a stabilizer satisfying these requirements.
SUMMARY OF THE INVENTION
A stabilized isothiazolone solution is provided that is useful as a disinfectant and antimicrobial agent, has high stability and can contain active ingredient in high concentration.
A method of stabilization of isothiazolone is also provided which can stabilize an 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 Mg
2+
from binding to ions contained in the industrial water such as PO
4
3−
, CO
3
2−
to form a Hard Scale and does not use stabilizers comprising ferric salts.
The present invention provides a stabilized isothiazolone composition comprising (a) an isothiazolone of formula I, (b) sulfuric acid, and (c) solvent.
where
R
1
and R
2
each independently represent a hydrogen atom, a halogen atom, or a C
1
-C
4
alkyl group, or R
1
and R
2
together form a cyclic allyl group;
R
3
represents a hydrogen atom, C
1
-C
10
alkyl group which is substituted or unsubstituted with a halogen atom or hydroxy group, C
2
-C
10
alkenyl group which is substituted or unsubstituted with a halogen atom, C
2
-C
10
alkynyl group which is substituted or unsubstituted with a halogen atom, C
1
-C
10
alkyl group, or aralkyl group which is substituted or unsubstituted with C
2
-C
9
alkoxy group.
The present invention also provides a method of stabilization of isothiazolone comprising stabilizing isothiazolone by blending an isothiazolone and a stabilizer, where the isothiazolone is that of formula I, and 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 I, (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, the present invention utilizes sulfuric acid as a stabilizer. Thus, the degradation of isothiazolone can be inhibited, and even completely prevented according to the present invention.
The stabilized isothiazolone solution of the present invention includes an isothiazolone compound represented by formula I, sulfuric acid and solvent.
The isothiazolone compound which may be used in the present invention illustratively includes one or more compounds selected from the group represented by formula 1, preferably one or more compounds such as 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 is high purity, such as spectroscopic or reagent grades.
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 I, 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 I, 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 I, 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 sta
Choi Ki-Seung
Ha Jae-Min
Hahn Soon-Jong
Kim Gi-Bae
Kim Jin-Man
Gifford, Krass, Groh Sprinkle, Anderson & Citkowski, P.C.
Levy Neil S.
SK Chemicals
LandOfFree
Stabilized isothiazolone compositions and methods of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Stabilized isothiazolone compositions and methods of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stabilized isothiazolone compositions and methods of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3068687