RU2542278C2 - Biocidal composition - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention aims at processing and decontaminating aqueous media of various types for the purpose of microorganism protective, particularly cooling water of cooling towers, heat-exchange equipment for preventing biological growth of heat-exchange surfaces and other industrial systems. The biocidal composition for processing the aqueous media involves polyhexamethyleneguanidine compounds, isothiasolinone compounds and non-ionic surfactants.

EFFECT: invention enables producing the composition having the high biocidal activity on bacteria, fungi and algae.

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Description

The invention relates to biocides for the treatment and disinfection of various types of aqueous media in order to protect them from microorganisms, in particular cooling water cooling towers, heat exchange equipment to prevent biological fouling of heat transfer surfaces and other industrial systems.

Bio-growth and contamination by microorganisms are associated with the deposition of microbes or the formation of biofilms on virtually any surface immersed in an aqueous medium. In water cooling systems, the presence of a biofilm reduces the rate of heat transfer and contaminates pipelines and heat transfer pipes, as a result, friction resistance increases significantly and a large amount of energy is consumed for pumping liquid. It is also known that the occurrence of severe corrosion may result from the formation of acids associated with the growth of biofilms of certain bacteria. Known methods of suppressing microorganisms in aqueous systems, including treatment with oxidative biocides: chlorine, bromine, chlorine dioxide, chloroisocyanurates. Non-oxidizing biocides can also be used: quaternary ammonium compounds, aldehydes, para-aminobenzoic acids and organic sulfur compounds. Isothiazoline compounds are known as highly effective biocides that suppress the vital activity of various microorganisms.

Known disinfectant composition for disinfection in medicine with enhanced bactericidal properties, containing 1-15% solution of guanidines: biguanidine or polyhexamethylene guanidine and a 0.1-3% solution of a mixture of quaternary ammonium compounds [RF Patent 2282463, IPC A61L 2/16, A61L 2/18, publ. August 27, 2006]. The disadvantage of this composition is the low degree of suppression of the growth of algae, fungi in cooling water and the need for large doses of this biocidal composition.

A known composition containing 10-20 wt.% A disinfecting agent and 10-15 wt.% Surfactants, where polyhexamethylene guanidine phosphate or polyhexamethylene guanidine chloride is used as a disinfectant, and a mixture of nonionic polyalkylene oxide and sodium alkylbenzenesulfonate is used as a surfactant when the mass ratio of 4: 1-3: 2 [RF Patent 2177499, IPC C11D 3/48, C11D 1/83, A61L 2/18, publ. 12/27/2001]. The disadvantage of this composition is the limited scope - mainly in medicine, veterinary medicine, food industry, for domestic use. The use of this composition for the disinfection of industrial and waste water is undesirable due to the high content of surfactants. A high concentration of surfactants in the circulating water supply system can lead to foaming, the formation of air cushions and a decrease in heat removal.

Known biocidal composition for treating industrial waters, preventing the growth of bacteria and fungi, containing 10-90 wt.% Dodecylguanidine hydrochloride and 10-90 wt.% A mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl -4-isothiazolin-3-one with a ratio of 1.15: 0.35 [US Patent 4661503, IPC A01N 47/44, publ. 04/28/1987]. The disadvantage of this biocidal composition is the need to use large concentrations of guanidines and isothiazolinones to obtain the biocidal effect, which limits the scope of the product and complicates the process of preparing the solution due to the formation of a precipitate when using significant concentrations of isothiazolones.

Known biocidal composition containing a biguanidine polymer, chloromethylisothiazolinone and / or methylisothiazolinone, glycol and water [Japanese Application 2002301144, IPC A61L 9/01, publ. 10/15/2002]. The biocidal composition has the following content of components, wt.%:

Biguanidine polymer 5,0 Glycol 0-5.0 Isothiazolone Compounds 0-0.5 Water rest

This composition is mainly used for deodorizing air in residential buildings. The disadvantage of the composition is that it contains a low concentration of the main components in terms of the main substance. Very high doses of this drug are needed to disinfect industrial water. In addition, the high concentration of glycols with respect to the main disinfectants: biguanidins and isothiazolones is also a disadvantage, since large doses of glycols in industrial water can serve as an additional source of nutrition for microorganisms. The composition is an aerosol, which narrows the scope of its application and, accordingly, it cannot be used for water treatment.

Closest to the claimed is a biocidal composition containing 3-isothiazolone and polyhexamethylene guanidine phosphate in a ratio of 1: 1 to 1: 4, in which 3-isothiazolone is a mixture consisting of 3-isothiazolone having R - hydrogen and 3-isothiazolone, having R - chlorine in a ratio of from 1:20 to 20: 1 [US 20050101648, IPC A61K 31/155, publ. 05/12/2005]. The disadvantage of this composition is the high content of isothiazolones, which is not economically feasible, as well as the need to use high doses of the drug 50-200 mg / L. In addition, the composition has low efficiency with respect to bacteria, algae and fungi adsorbed to the surface of the heat exchange equipment.

The objective of the invention is to develop a biocidal composition for the treatment of aqueous media with high biocidal activity simultaneously against bacteria, fungi and algae.

The problem is solved by creating a biocidal composition for the treatment of aqueous media, including polyhexamethylene guanidine compounds, isothiazolinone compounds, nonionic surfactants in the following ratio, wt.%:

polyhexamethylene guanidine compounds 5-50 isothiazolinone compounds 0.1-2 nonionic surfactants 0.05-5 water rest

The use of surfactants in the composition of the biocidal composition is very important for the fight against microorganisms, fungi and algae adsorbed on a solid surface. Adsorption has been established for the most diverse groups of microorganisms: spore and non-spore, gram-positive and gram-negative, proactinomycetes, yeast, mycoplasmas, viruses and phages, actinomycetes; mushrooms, algae; protozoa animals. Adhesive cells of algae, fungi and microorganisms are more resistant to the action of bactericides. Due to the use of surfactants in the composition of the biocidal composition, the effectiveness of the composition is increased by improving penetration through cell membranes.

As polyguanidine compounds, chloride, bromide, iodide, polyhexamethylene guanidine fluoride, phosphate, citrate, gluconate, polyhexamethylene guanidine oxalate or mixtures thereof are used.

As isothiazolinone compounds, isothiazolin-3-ones produced for example by Rohm and Haas Company, under the trade name Kathon®, such as: 2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin -3-one, 2-octyl-4-isothiazolin-3-one, 4,5-dichloro-N-octyl-4-isothiazolin-3-one, 1,2-benzisothiazolin-3-one, N- (h- butyl) -1,2-benzisothiazolin-3-one, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, or mixtures thereof.

As nonionic surfactants, ethoxylated fatty alcohols (C ₁₀ -C ₁₈ ) with an ethoxylation degree of 3-20 and / or ethoxylated nonylphenols with an ethoxylation degree of 6-25 and / or ethoxylated fatty acids C ₁₄ -C ₁₈ with an ethoxylation degree of 1- can be used. 20 and / or block copolymers of propylene oxide and ethylene oxide.

As ethoxylated alcohols, compounds can be used which are ethoxylated fatty alcohols (C ₁₀ -C ₁₈ ) with a degree of hydroxyethylation of 3-20, for example, Sintanol DT-7 - ethoxylated fatty alcohols C ₁₀ -C ₁₃ with a degree of oxyethylation of 7, Sintanol DS -10 - C ₁₀ -C ₁₈ ethoxylated fatty alcohols with an ethoxylation degree of 8-10; OS-20 preparation - C ₁₄ -C ₁₈ ethoxylated alcohols with an ethoxylation degree of 20.

As ethoxylated nonylphenols with a degree of hydroxyethylation of 6-25, for example, neonols, nonylphenol with a degree of hydroxyethylation of 6 AF9-6, ethoxylated nonylphenol with a degree of oxyethylation of 12 AF9-12 and ethoxylated nonylphenol with a degree of oxyethylation of 25 can be used.

As oxyethylated fatty acids C ₁₄ -C ₁₈ with a degree of ethoxylation of 1-20 can be used ethoxylated stearic acid, for example, PEG-400 monostearat; ethoxylated lauric acid, for example, PEG-400 monolaurat; ethoxylated oleic acid, for example, PEG-400 monooleat.

As block copolymers of propylene oxide and ethylene oxide can be used commercially available reagents, for example, preparations of the company BASF, such as Lupranol 2090, Lupranol 2095.

Using the combination of essential features according to the proposed composition allows to achieve high biocidal activity both against bacteria, and against fungi, and against algae and to obtain a synergistic effect from the use of the proposed composition, the possibility of which does not follow from the prior art and not described for one similar composition. Known from the prior art, the solutions do not confirm the popularity of the influence of the features of the claimed invention on the achieved technical result.

The bactericidal effect of the composition is tested by seeding samples on meat-peptone agar (ΜΠΑ), on which many heterotrophic microorganisms of various systematic and physiological groups develop: gram-negative, endospore-free bacteria of the genera Pseudomonas, Flavobacterium and Achromobacter, gram-positive bacilli of the genus Bacilluscococcus and coccus genus other bacteria.

The method is based on the seeding of a certain amount of water sample on a tight Пет in Petri dishes, incubation at a temperature of 28-30 ° C for 3-5 days, counting the grown colonies and determining the most probable number of microorganisms in 1 ml of test water [Microbiology Ed. . Egorova N.S. -M .: Ed. Moscow. Univ., 1976. - P.307; D.G. Zvyagintsev. Methods of soil microbiology and biochemistry. M .: Publishing. Moscow. University, 1991. - S.304].

To study the algicidal properties of biocides, Chlorella vulgaris was used as a test culture. 250 ml of dechlorinated water and an algologically pure culture grown in Tamiya medium are placed in flasks. Various doses of biocides are added to the studied media; the effectiveness is determined in comparison with the control experiment without the addition of a biocide. Experienced and control flasks withstand in the minostat from 1 to 14 days under daylight illumination of 2000 lux and without illumination at night. Daily conduct visual observations and microscopy. By the color change of algae, the onset of the inhibitory effect of the biocide is noted.

The study of the fungicidal ability of biocides is carried out according to the following method. The fungi (Aspergillus, Trichoderma, Fusarium, etc.) are identified and their abundance taken into account by seeding the test water in Petri dishes on Saburo medium acidified with lactic acid to pH 4.0-4.5 and then counting the grown colonies in 5-7 days .

Crops are incubated in a thermostat at a temperature of 28-30 ° C or at room temperature. The result is expressed as a% decrease in growth compared to the control experiment.

The synergy index is calculated according to the method published in the work of the author Kull F.С. et al. (Appl. Microbiol. 9:53 8.about. 544 (1961)). According to this method, the synergistic effect of the biocide is manifested when the sum of QA / Qa, QB / Qb and QC / Qc is less than 1, according to the equation:

SI is the synergy index;

Qa is the dose (mg / l) of one guanidine;

Qb is the dose (mg / l) of one isothiazolinone;

Qc - dose (mg / l) of one nonionic surfactant;

QA is the dose (mg / l) of guanidine in the mixture;

QB is the dose (mg / l) of isothiazolinone in the mixture;

QC - dose (mg / l) of nonionic surfactant in the mixture.

The proposed biocidal compositions are prepared as follows. An aqueous solution of the polyhexamethylene guanidine compound is prepared with constant stirring of the solution with a pump and a temperature of 60 ° C, it is cooled to 25-40 ° C, a nonionic surfactant is added, then the isothiazolinone compound is introduced.

The implementation of the invention is illustrated by the following examples containing the conditions for the preparation of biocidal compositions and the conditions for their testing.

Example 1

Desalted water is poured into a container with a stirrer and a pump, heated to 60 ° C, and polyhexamethylene guanidine phosphate is dissolved with constant stirring, cooled to 30 ° C. Then, 5-chloro-2-methyl-4-isothiazolin-3-one is added to the resulting solution. Then, to 99 kg of the prepared solution, 1 kg of C ₁₀ ethoxylated fatty alcohol with a degree of hydroxyethylation of 6 is introduced. The obtained test results of the compositions are presented in Tables 2, 4, 5.

Example 2

The preparation of the biocidal composition is carried out analogously to example 1, but to 98 kg of the prepared solution, 2 kg of a mixture of C ₁₆ ethoxylated fatty alcohol with an ethoxylation degree of 10 and ethoxylated nonylphenol with an ethoxylation degree of 22 are added. The obtained test results of the compositions are presented in Tables 2, 4, 5.

Example 3

Preparation of the biocidal composition is carried out analogously to example 1, but to 95 kg of the prepared solution, 5 kg of ethoxylated nonylphenol with a degree of hydroxyethylation of 8 are introduced. The obtained test results of the compositions are presented in tables 2, 4, 5.

Example 4

An aqueous solution of polyhexamethylene guanidine chloride is prepared by constantly stirring the solution with a pump and a temperature of 60 ° C, cool to 25-40 ° C, add ethoxylated fatty alcohol (C ₁₂ ) with a degree of hydroxyethylation of 10, then add 5-chloro-2-methyl-4-isothiazoline -3-he. The composition and ratio of components are presented in table 1, the obtained test results of the compositions are presented in tables 2-5.

Examples 5-9

The preparation of biocidal compositions and their testing is carried out analogously to example 1. The composition and ratio of components are presented in table 1, the obtained test results of the compositions are presented in tables 2-5.

Tables 2-5 show comparative data on the biocidal properties of the claimed composition in comparison with known biocides.

Table 2 presents the results of a study of the decrease in the number of bacteria under the action of the inventive biocidal composition in comparison with single-component biocides: 20% guanidine solution, 15% isothiazolinone solution. To determine the biocidal effectiveness of the claimed composition, comparative tests of one-component biocides were carried out at the same doses: 10, 20, 30 mg / L. The solution in which the biocide was not added was used as a control sample.

As shown in table 2, one-component biocides: 20% guanidine solution and 15% isothiazolinone solution at high doses inhibit bacterial growth. When using the inventive composition, the optimal effective doses of reagents in terms of the main substance are lower than when using single-component biocides.

As can be seen from the data presented in table 3, the same inhibitory effect on microorganisms can be obtained even if several times smaller doses of reagents are used, if used in the composition. The use of small doses of surfactants without biocides leads to increased growth of bacteria, algae and fungi. Only high doses of more than 1 g / l are effective, but such an increase can lead to foaming of water. As a result, it was found that the growth of microorganisms is more effectively suppressed by a mixture of the three compounds mentioned above, compared to using each compound separately.

Table 4 presents comparative data on the suppression of the growth of green algae-chlorella under the action of the claimed composition in comparison with the action of single-component biocides: 20% guanidine solution, 15% isothiazolinone solution.

From the data presented in table 4, it follows that the studied doses of one-component biocides: 20% guanidine solution and 15% isothiazolinone solution are inferior in algicidal properties to the effectiveness of the claimed composition.

Table 5 presents the results of a study of fungicidal efficacy by the action of the inventive biocidal composition in comparison with single-component biocides: 20% guanidine solution, 15% isothiazolinone solution.

As can be seen from the data of table 5, the fungicidal ability of the claimed composition is higher than single-component biocides, such as 20% guanidine solution or 15% isothiazolinone solution. The high fungicidal effect of the claimed composition is manifested even at a low dose of 10 mg / L.

The data in tables 2-5 show the high efficiency of the inventive biocidal composition both against bacteria, and against fungi, and against algae, which is not achieved by using any known biocidal composition described in the literature. The inventive composition allows to increase biocidal activity compared with known means, while it exhibits a synergistic effect and allows the use of low concentrations - only 0,0002-0,003% based on the amount of active substances. A comparison of the results of biological tests (table 2-5) shows that the claimed biocidal composition has both high bactericidal, algecidal and fungicidal efficacy. The use of the inventive biocidal composition in the conditions of pilot tests on equipment having significant biological deposits has shown high efficiency with respect to bacteria, algae, and fungi already adsorbed to the surface of the heat exchange equipment.

Claims (1)

Biocidal composition for treating aqueous media, including polyhexamethylene guanidine compounds, isothiazolinone compounds, nonionic surfactants in the following ratio, wt.%:
polyhexamethylene guanidine compounds 5-50 isothiazolinone compounds 0.1-2 nonionic surfactants 0.05-5 water rest