BACTERIOSTATIC COMPOSITIONS AND USE IN METAL WORKING FLUIDS

Abstract: The present invention concerns bacteriostatic compositions comprising a bacteriostatic agent selected from the group comprising amides and amine salts of normal heptanoic acid and amides, amine salts and alkyleneoxide addition compounds of undecylenic acid. It also concerns the use of said compositions in the field of metal working fluids.

Description: Bacteriostatic compositions and use in metal working fluids. This invention relates to basteriostatic compositions used in metal working such as cutting and grinding of metals. It is known that aqueous metal working liquid contains, as an effective com¬ ponent, organic compound and hence is deteriorated or become rotten by bateria or molds. In fact, microorganismes which enter into a working liquid utilize organic oil compounds in the working liquid as nutritive substance and multiply gradually, resul¬ ting in putrefaction of the oil components. Therefore, antiseptic agent is added to working liquid to prevent it from such putrefaction. It is a recent trend to develop anti- microorganismes type metal working liquids as well as to improve performance of the working liquid. Examples of the antiseptic agent are organic nitrogen-containing compounds such as triazines, thiazines, isothiazolines such as Keson (trade name) and pyrizi- nes. Phenol type compounds and boron type compounds are also envisaged. Generally, aqueous working liquid or coolant is poured onto a working point and is recycled. Aqueous working liquid, however, deteriorates gradually, resulting in stinking, lowering of pH which causes corrosion as well as a decrease of lubrication efficiency. The most serious problem is clogging of piping caused by generation of slime (mold). Known antiseptic agents mentioned above are useful to solve the problems. However, they are not perfect but have some problem in at least one of problems in corrosion, decomposition, stink, foam and waste liquid. Therefore, there is a demand to develop bioactive type aqueous working liquid which can solve the problems, give less bad influence to human body and environment and which is easy to manage. An object of the present invention is to provide a bacteriostatic composition. Another object of the present invention is to use said composition for metal working improved in bacteriostatic property. In order to solve the problems, the present inventors found that additives selected from the group comprising amides and amine salts of heptanoic acid or amides, amine salts and alkyleneoxide addition compounds of undecylenic acid possess excellent bacteriostatic property in metal working liquids. Thus, the present invention provides bacteriostatic compositions for metal working containing at least one compound as mentioned above, said compositions being used in aqueous or emulsion type metal working liquids. The additive according to the present invention is selected from the group comprising amides and amine salts of heptanoic acid and amides, amine salts and alkyleneoxide addition compounds of undecylenic acid. Derivatives of heptanoic acid are selected among : (a) amides of formula : ft , R 1 H 3 C-(CH 2 ) 5 -C-N R 2 in which Ri and R2, identical or different, represent H, a C-|_20 alkyl group or a C-|. 20 alkyl group having hydrophilic group, and (b) amine salts of formula : H 3 C-(CH 2 ) 5 -C00 -R% in which R3 represents a primary or secondary alkyl or alkanol amine salt. Derivatives of undecylenic acid are selected among: (a) amides of formula : ft , R 1 H 2 C = CH-(CH 2 ) 8 -C-N in which R-| and R2, identical or different, represent H, a C-|_20 alkyl group or a C-|_20 alkyl group having hydrophilic group, (b) amine salts of formula: H 2 C = CH-(CH 2 ) 8 -COO " R3 in which R3 represents a primary or secondary alkyl or alkanol amine salt, and (c) alkyleneoxide addition compouds of formula : o II x i H 2 C=CH-(CH 2 ) 8 -C-(0CH 2 -CH) n -0H in which X represents H or a methyl group and n represents an integer of 1 to 50. Amides and amine salts of heptanoic or undecylenic acid can be easily pre¬ pared by a reaction between the corresponding acid and an organic nitrogen-contai¬ ning compound such as monoalkylamine and dialkylamine of carbon number of 1 to 20, cyclohexylamine, dicyclohexyl amine, or those whose alkyl has at least one hydrophilic group such as monoethanol amine or diethanol amine. Alkyleneoxide addition compounds of undecylenic acid can be prepared by a reaction between undecylenic acid and the corresponding alkyleneoxide compound. When more than two compounds are selected and combined in the group comprising amides and amine salts of heptanoic acid and amides, amine salts and alkyleneoxide addition compounds of undecylenic acid, the ratio of these derivatives of heptanoic acid and undecylenic acid is not specially limited but can be in range of 9:1 to 1 :9, preferably 8:2 to 2:8. The content of amides and amine salts of heptanoic acid or amides, amine salts and alkyleneoxide addition compounds of undecylenic acid in a working liquid is not specially limited but can be in a range of 0.01 to 40 %, preferably 0.1 to 20 %, more preferably 0.5 to 10 % by weight of the total amount of the composition. If the content of amides and amine salts of heptanoic acid or amides, amine salts and alkyleneoxide addition compounds of undecylenic acid is not sufficient, satisfactory bacteriostatic effect in metal working liquid can not be expected. On the contrary, excess amount thereof does not improve bacteriostatic property and is not economical. The composition according to the present invention can also contain other optional additives such as surfactants, anti-corrosion agents and extreme pressure additives in addition to the bacteriostatic additive. The proportion of these additives is not specially limited but is less than 10 %, preferably less than 5 % by weight of the total amount of the composition. The amide or amine salt of heptoic acid or amide, amine salt or alkyle- neoxide addition compound of undecylenic acid is mixed with mineral oil or machine oil to prepare aqueous or emulsion type metal working liquid. The present invention provides a non-smell bacteriostatic agent for metal working liquid and a metal working liquid having bacteriostatic property. Since the bacteriostatic additive of the present invention is derived from nature product, the metal working liquid obtained therefrom does not irritate skin and is mild for human being and environment. The present invention is illustrated by Examples but is not limited thereto. Tests of bacteriostatic property and stink 2 parts by weight of bacteriostatic agent are added to 100 parts by weight of a typical metal working liquid and changes in the number of living fungi and stink are measured. The typical metal working liquid has the following composition (in parts by weight) : 10 machine oil 50 ethyleneoxide addition product of ricinoleic acid 10 chlorinated paraffin 16 water 24 Evaluation methods The sample containing the bacteriostatic agent and the typical metal working liquid is placed in an incubator kept at 30°C and the number of living fungi is counted with an organism counter (Sanai Biochecker TTC : total fungi number counter type) after 1 , 2, 3, 6 and 10 days. Stink is evaluated by the sense of smell of human being after 10 days. In a comparative example, no bacteriostatic agent is added. EXAMPLE 1 2 parts by weight of monoethanolamide of undecylenic acid is added to 100 parts by weight of the typical metal working liquid. The results, shown in Table 1 , reveal that the number of living fungi increases in time but is controlled to a value of 10^ after 10 days. No stink is obser¬ ved after 10 days. EXAMPLE 2 The procedure of Example 1 is repeated except that the bacteriostatic agent is a mixture of monoethanolamide of heptanoic acid/monoethanolamide of unde¬ cylenic acid (1 :1). The results are shown in Table 1. EXAMPLE 3 The procedure of Example 1 is repeated except that the bacteriostatic agent is an ethyleneoxide addition product of undecylenic acid (n=6). The results are shown in Table 1. The results of Examples 1 , 2 and 3 reveal that compositions containing the bacteriostatic agent according to the present invention show improved bacteriostatic property comparing to the Comparative Example.

Claims: CLAIMS 1. Bacteriostatic composition, in particular for metal working, comprising at least one heptanoic acid derivative and/or undecylenic acid derivative. 2. Composition according to claim 1 wherein said derivative of heptanoic acid is selected from the group comprising : (a) amides of formula : ft R ι H 3 C - (CH 2 ) 5 - C - N R 2 in which R-j and R2, identical or different, represent H, a C « |_20 alkyl group or a C<|_20 alkyl group having hydrophilic group, and (b) amine salts of formula : H 3 C - (CH 2 ) 5 - COO " R 3 in which R3 represents a primary or secondary alkyl or alkanol amine salt. 3. Composition according to claim 1 wherein said derivative of undecylenic acid is selected from the group comprising : (a) amides of formula : O H 2 C : CH - (CH 2 ) 8 - C - in which R-| and R2, identical or different, represent H, a C<|_20 alkyl group or a C-|_20 alkyl group having hydrophilic group, (b) amine salts of formula: H 2 C = CH - (C H 2 ) 8 - C00 " R 3 in which R3 represents a primary or secondary alkyl or alkanol amine salt, and (c) alkyleneoxide addition compouds of formula : O X II i H 2 C = CH-(CH 2 ) 8 -C-(0CH 2 -CH) n -0H in which X represents H or a methyl group and n represents an integer of 1 to 50. 4. Composition according to any claim 1 to 3 comprising 0.01 to 40 % by weight of said heptanoic or undecylenic acid derivative. 5. Use of the composition set forth in claims 1 to 4 in metal working fluids.

Inventors: CAUPIN HENRI-JEAN, HATANAKA TOSHIFUMI, KAWAMURA TETSUSHI, YONEKURA AKI, CAUPIN, HENRI-JEAN, HATANAKA, TOSHIFUMI, KAWAMURA, TETSUSHI, YONEKURA, AKI
Applicants: ATOCHEM ELF SA, CAUPIN HENRI JEAN, HATANAKA TOSHIFUMI, KAWAMURA TETSUSHI, YONEKURA AKI, CAUPIN, HENRI-JEAN, ELF ATOCHEM S.A., HATANAKA, TOSHIFUMI, KAWAMURA, TETSUSHI, YONEKURA, AKI
Application year: 1996
Main classification: C10M173
IPC codes: A01N37, A01N47, C10M169, C10M173, C10N30, C10N40