Composition for controlling the growth of algae, fungi and pathogenic organisms in water
View Patent ↗A stable aqueous concentrate comprising a polymeric biguanide, a chelating agent and a water-miscible organic solvent for controlling the growth of algae, fungi and pathogenic organisms in water.
1. A freeze-thaw stable aqueous polymeric biguanide composition comprising:
(a) from 5 to 25 parts of a polymeric biguanide or salt thereof;
(b) at least 3 parts of a chelating agent;
(c) at least 1 part of propylene glycol; and
(d) up to 91 parts water;
wherein all parts are by weight and the parts (a)+(b)+(c)+(d)≈100, whereby said composition has improved resistance against formation of cloudiness when the composition is subjected to freeze-thaw conditions.
2. A composition according to claim 1 comprising:
from 10 to 25 parts of the polymeric biguanide or salt thereof;
from 3 to 30 parts of the chelating agent;
from 1 to 40 parts of propylene glycol; and
from 5 to 86 parts water;
wherein all parts are by weight and the parts (a)+(b)+(c)+(d)=100.
3. A composition according to claim 1 wherein the polymeric biguanide comprises at least two biguanide units of Formula (1):
which are linked by a bridging group which contains at least one methylene group.
4. A composition according to claim 1 wherein the polymeric biguanide comprises a linear polymeric biguanide which as a recurring polymeric chain represented by Formula (4) or a salt thereof:
wherein X and Y represent bridging groups in which together the total number of carbon atoms directly interposed between the pairs of nitrogen atoms linked by X and Y is more than 9 and less than 17.
5. A composition according to claim 1 wherein the chelating agent is ethylenediaminetetraacetic acid or a salt thereof.
6. A composition according to claim 1 where the pH is in the range of from 8.0 to 11.0.
7. A freeze-thaw stable aqueous polymeric biguanide composition comprising:
(a) from 5 to 25 parts of a polymeric biguanide or salt thereof;
(b) from 3 to 30 parts of EDTA or a salt thereof;
(c) from 20 to 35 parts of propylene glycol; and
(d) 10 to 72 parts water;
wherein all parts are by weight and the parts (a)+(b)+(c)+(d)=100, whereby said composition has improved resistance against formation of cloudiness when the composition is subjected to freeze-thaw conditions.
8. A freeze-thaw stable aqueous polymeric biguanide composition comprising:
(a) from 5 to 25 parts of a polymeric biguanide or salt thereof;
(b) from 5 to 20 parts of EDTA or a salt thereof;
(c) from 20 to 35 parts of propylene glycol; and
(d) 20 to 72 parts water;
wherein all parts are by weight and the parts (a)+(b)+(c)+(d)=100, whereby said composition has improved resistance against formation of cloudiness when the composition is subjected to freeze-thaw conditions.
9. A composition according to claim 1 , wherein the polymeric biguanide is a mixture of polymer chains in which the individual polymer chains, excluding the terminating groups, are of the Formula (5) or a salt thereof:
wherein n is from 4 to 40.
10. A composition according to claim 9 , wherein n is from 4 to 15.
11. A method for preparing a stable aqueous polymeric biguanide composition comprising: mixing the following ingredients to form a solution of the polymeric biguanide:
(a) from 5 to 25 parts of a polymeric biguanide or salt thereof;
(b) at least 3 parts of a chelating agent;
(c) at least 1 part of a propylene glycol; and
(d) up to 91 parts water;
wherein all parts are by weight and the parts (a)+(b)+(c)+(d)=100, whereby the resulting composition has improved resistance against becoming cloudy when subject to freeze-thaw conditions.
12. A method according to claim 11 , wherein the ingredients are mixed at a temperature in the range of 40° C. to 80° C.
13. A method accoarding to claim 11 , further comprising filtering the resulting composition to remove particulate matter.
14. A method according to claim 11 , which comprises mixing the ingredients (a), (b), (c) and (d) in the following amounts, by weight,
(a) 5 to 25 parts
(b) 3 to 30 parts
(c) 20 to 35 parts
(d) 10 to 72 parts.
15. A method according to claim 11 , which comprises mixing the ingredients (a), (b), (c) and (d) in the following amounts, by weight,
(a) 5 to 25 parts
(b) 5 to 20 parts
(c) 20 to 35 parts
(d) 20 to 70 parts.
16. A method according to claim 11 , wherein the chelating agent (b) is ethylenediamine tetraacetic acid or salt thereof.
17. A method according to claim 16 , which comprises mixing the ingredients (a), (b), (c) and (d) in the following amount, by weight,
(a) 5 to 25 parts
(b) 5 to 20 parts
(c) 20 to 35 parts
(d) 20 to 70 parts.
18. A method according to claim 17 , which comprises mixing (b) and (c) in a ratio, by weight, of (b):(c) from 1.6 to 3.0:1.00.
19. A method according to claim 17 , which comprises mixing (b) and (c) in a ratio, by weight, of (b):(c) from 1.65 to 2.50:1.00.
20. A method according to claim 17 , which comprises mixing (b) and (c) in a ratio, by weight, of (b):(c) from 1.70 to 2.0:1.00.
21. A method according to claim 11 , wherein (b) is ethylenediamine tetraacetic acid or salt thereof and wherein the mixing weight ratio of (b):(c) is from 1.70 to 2.00:1.
22. A method according to claim 21 , further comprising adjusting the pH of the resulting composition to within the range of from 8.0 to 9.9.
23. A freeze-thaw stable aqueous polymeric biguanide composition prepared according to the method of claim 11 .
24. A method for treating recreational or industrial water comprising adding a microbiologically effective amount of the composition according to claim 1 to said recreational or industrial water.
25. A method for treating recreational or industrial water comprising adding a microbiologically effective amount of the composition according to claim 7 to said recreational or industrial water.
26. A method according to claim 25 , which comprises adding the composition in amount sufficient to provide from 3 to 14 ppm of polymeric biguanide or salt thereof and from 6 to 10 ppm of chelating agent in the water to the treated.