CS226972B1 - Synthetic concentrated cutting compound for metal machining and method of preparing same - Google Patents

Description

Concentrated synthetic cutting fluid for metal machining and process of its preparation

BACKGROUND OF THE INVENTION The present invention relates to a composition and a method for producing a concentrated cutting fluid for metalworking, including grinding, especially cast iron and steel.

The machining process and its production depend largely on the utility properties of cutting fluids, especially on new types developed on the basis of a deeper understanding of the mechanism of their effect on the technological process of machining. The main technological parameters of the cutting fluid must be with lubricating ability to reduce the influence of friction during machining, cooling ability, ie heat dissipation exceeding locally even 1 237 K, which is given by good heat transfer coefficient, good thermal conductivity and thermal stability, material and machinery against corrosion, ability to remove chips and abrasion from the working tool, resistance to microbial degradation and ecological safety.

Hitherto, aqueous electrolyte solutions, water-based oil emulsion fluids, cutting oils or synthetic fluids have been used as cutting fluids. Electrolyte-based cutting fluids are characterized by a high cooling effect, but their lubricating efficiency is very low, almost zero. Cutting emulsion fluids also have a good cooling effect but poor lubricity; they require complex preparation and are easily biodegradable in operation. Mineral cutting oils, possibly in combination with vegetable oils and high-pressure additives, have a high lubricating efficiency but not a very cooling effect. The disadvantage of this type is the fact that complex surface degreasing of the workpieces must be carried out before the surface treatment.

Synthetic cutting fluids do not have the drawbacks of these types, but they do

226 972

226,972 Inorganic-based corrosion inhibitors (nitrites), such as liquid according to U.S. Pat. A.O. C.

196 907 or some foreign liquids, which is not fully satisfactory, ecologically.

The above-mentioned drawbacks are overcome by the concentrated synthetic cutting fluid according to the invention, which comprises 2 to 5 wt. an alkali metal mercaptobenzothiazole corrosion inhibitor which at the same time prevents microbial deterioration of 10 to 20 wt. a corrosive passivator, which is a neutralization product of an inorganic or organic acid (preferably boric or phosphoric acid) with amines having a hydroxyl group and optionally an aromatic group in their molecule, in particular aliphatic and cyclic amines containing 4 to 6 carbon atoms, which act as pH stabilizer, and 6 ', up to 20 wt. lubricants, which are polyhydric alcohols containing 6 to 60 carbon atoms and at least two alcohol groups. The overall composition may be supplemented with a suitable opaque perfume and colorant. The remainder to 100 wt. water.

To prepare a concentrated synthetic cutting fluid according to the invention, the mercaptobenzothiazole is added with stirring to a solution formed by dissolving a portion of the hydroxyl group amine in water (about 20% by weight of the total amine is diluted with water in a weight ratio of about 1: 5). the alkali metal hydroxide and the resulting suspension is stirred for at least 3 hours at 343-353 K. After 12 hours of sedimentation, the clear solution is filtered off. Separately prepare a solution of the acid in the remaining amine by stirring for two hours at a temperature of 333 to 348 K.

The two solutions are mixed, polyhydric alcohol and the rest of the water are added and the mixture is perfectly homogenized.

The essence of the production processes of most cutting fluids is usually simple mixing or emulsification of individual components. However, the liquid according to the invention cannot be prepared in this way; this must be done as the corresponding corrosion inhibitors and passivators, namely the alkali metal mercaptobenzothiazole and the acid neutralization product with amines, do not dissolve in the aqueous solution of polyhydric alcohols and by mixing it is not possible to achieve a uniform content in each sample unit. Therefore, it is necessary to modify the manufacturing process by first preparing separately the two solutions, which are then mixed and treated.

The concentrated cutting fluid of the present invention has a number of advantages over prior art formulations. It provides protection against corrosion of metals of workpieces and machinery, while the workpieces require no pretreatment such as sweeping, passivation, etc. prior to painting and the like. The liquid has a high cooling efficiency in terms of wettability, thermal conductivity and a suitable heat transfer coefficient. It also has the necessary lubrication efficiency in machining. The favorable concentration of hydrogen ions (pH 8.8 to 9.2) limits the effect on equipment operators, paint systems; machinery and lubricants in sliding places to a minimum. The liquid according to the invention also has a high irrigation capability, in particular of an abrasive wheel during grinding, but also good stability against bacterial attack during long-term operation and ecological safety.

The cutting fluid according to the invention is a concentrated preparation which is diluted before use with water in a ratio of 1:20 to 1.50, which can be carried out directly in the production plant, thus avoiding pre-preparation. This also represents some savings for the consumer in transport and storage.

Examples

Preparation method

226 972

Mercaptobenzothiazole ββ is added with stirring to the solution formed by dissolving a portion of the hydroxyl group amine in water (20% by weight of the total amine is diluted 1: 5 with water), then solid alkali metal hydroxide is metered in and the resulting suspension stirred for at least 3 hours. at 343-353 K. After 12 hours of sedimentation, a clear solution was filtered. Separately a solution of the acid in the remaining amine is prepared by stirring for 2 hours at 333 and 346. The two solutions are mixed, polyhydric alcohol and the rest of the water are added and the mixture is perfectly homogenized. The resulting pH of concentrated synthetic. beet liquid is in the range of 8.8 to 9.2.

Example of composition Example 1

2-mercaptobenzothiazole potassium hydroxide triethanolamine boric acid polyethylene glycol mol.wt. 300 science

Example 2

Sodium 2-mercaptobenzothiazole dihydroxide diethanolamine phosphoric acid (100%) polyethylene glycol mol. 600 water

Example 3

2-mercaptobenzothiazole potassium hydroxide triethanolamine citric acid polyethylene glycol mol.wt. 300 water

2.5 wt.

1.2% 10, -8 wt.

3.2 wt.

8.8 wt.

de 100 wt.

3.0 wt. 1.23 wt.

13.13 wt. 6.7 wt.

6.5% wt.

up to 100 wt.

2.0 wt. 1.12 wt.

10.8 wt. 10.0 wt. 12.0 wt. de 100 wt.

Claims (2)

SUBJECT OF THE INVENTION Concentrated synthetic cutting fluid for machining metals, in particular cast iron and ecel, characterized in that it contains 2 to 5 wt. % alkali salts of mercaptobehztiazel as corrosion inhibitor, 10 to 20 wt. corrosion passivators and pH stabilizers, forming the neutralization products of inorganic or organic acids, preferably boric or phosphoric acids, having, with the amines in their molecule, hydroxyl or aromatic groups, in particular aliphatic and cyclic amines containing 4 to 6 carbon atoms, furthermore 6 to 15 % hmpt. % of lubricants forming polyhydric alcohols having 6 to 60 carbon atoms and at least two alcohol groups, and the remainder to 100 wt. water. 2. A process according to claim 1, wherein the solid mercaptebenzothiazole suspension in an aqueous hydroxyl group amine solution is treated with an alkali metal hydroxide at a temperature of 343-3.3 K and then the solution is homogenized with a neutralization product solution. acids with amines with addition of water and polyhydric alcohol.