SU1708928A1 - Method for purifying metallic surface against fat impurities - Google Patents

Abstract

This invention relates to the chemical treatment of a metal surface. The purpose of the invention is to increase the cleaning efficiency. The cleaning method includes the jet treatment of the surface with a heated solution of ree gents under mechanical action with brushes, first with a solution containing, in wt%: oxyethylated on average 12 mol of ethylene oxide. Technical mixtures of isononylphenol isomers (neonol AF-9-12) 0.03- 0.10; water to 100, then a solution containing; wt.%: Sodium hydroxide 1.20- 3.60; sodium tripolyphosphate, 0.25-0.80; carboxymethyl cellulose, 0.20-0.60; water to SO, then with a solution containing, in wt%: sodium hydroxide 0.80-2.7U; ethylenediaminetetraacetic acid disodium salt (Trilon B) 0.10 -0.35; water up to 100, and then with a solution containing, in wt%, sodium hydroxide 0.80-2.70; triet, anolamine 0.12-0, ^ 5; ethylenediaminetetraacetic acid disodium salt (Trilon B ) 0.10-0.35; water up to 100. Increasing the cleaning efficiency is achieved by conducting the cleaning process s four stages. 2 table 9 ^ • The invention relates to mechanochemical cleaning of the surfaces of metal products from fatty contaminants and can be used in the metallurgical, machine-building, electronic industry, in particular for cleaning steel strip in For odstve shadow mask color picture tube .target invention - increasing ef- 1) projective ochistki.Sposob cleaning comprises blasting the surface of the heated solution under mechanical action brushes first solution containing, in weight%:.. .- On average, ethoxylated on 12 moles. Of ethylene oxide technical mixtures of isononylpheno-ac isomers with yooo

Description

la (neonol AF 9

12) 0.03-0.10

WaterLo 100

in the second stage, a solution containing, in wt.%:

Hydroxide

1.2-3.6

on three

Tripolyphosphate 0, .5-0,8

on three

Carboxymethyl, 2-0,6

cellulose

Water Up to 100,

at the third stage - with a solution,

containing, wt.%:

Hydroxide

0.8-2.7

on three

Dinitriev salt, these are diamine-tetraacetic

acids (Trilon B)

0.1-0.35 Up to 100,. Water

in the fourth stage - with a solution,

keep, masd:

Hydroxide

0.8-2.7

sodium 0.12-0.5

Three ethanolamine

Disodium salt

ethylenediaminetetraacetic acid (Trilon B)

P, 1-0.35 To 100.

Water

The method can be illustrated by the following example.

Example. For the preparation of cleaning solutions, weighed solids (sodium hydroxide, sodium tripolyphosphate, carboxymethylcellulose, Trilon B) are dissolved in a mixer with a stirrer filled with water at a temperature of 60-70 ° C. Triethanolamine and neonol AF 9-12 are introduced into the reactor either before filling it with water or after dissolving solid components in water. The order of introduction of components into the reactor does not affect the preparation and quality of the solutions. The resulting solutions are fed to the degreasing department via pipelines or in polyethylene containers, poured into the bathtubs of the washing machines to the required level.

Steel strips with a thickness of 0.1 mm manufactured by Westfalbnshtahl (Germany) with production of fatty contaminants (residues of rolling and conservation lubricants) in an amount of up to 200 mg / m are subjected to cleaning.

Cleaning includes continuous processing: belts, moving at a speed of 5 m / min, in four washers. All washers are provided with solution baths, solution pumps, solution feed nozzles and rotating brushes. After leaving the second washer, the tape is rinsed with a water jet and enters the third machine, after leaving the fourth machine, the tape is also rinsed with a water jet and fed for further processing. All baths are equipped with heaters for heating solutions to 80f5 C. The pressure at the nozzles is about 3 atm.

If excessive foaming occurs in the first washer, it is recommended to additionally add 1), 03-0.1 us.% Of antifoam agent, for example, GDP-1, to the additional washing solution, and an additional introduction into the alkaline solution of the third washer 0.12-0.5 wt. % triethanolamine to provide the necessary degree of tape protection against corrosion or in the presence of a pre-prepared solution in an amount sufficient for the third and fourth washing machines.

The compositions of the tested solutions, as well as all the comparative results of the experiments performed, are presented in Table 8.

The degree of cleaning — cleaning efficiency — was evaluated by the yield of shadow masks, i.e. on the percentage of suitable masks to the total number of masks.

Analysis of the data presented in Table 1 shows that a decrease in the concentrations of components below the proposed limit leads to a decrease in the efficiency of the purification process I, the use of solutions with components above the proposed limit does not affect the improvement of efficiency indicators, therefore it is not advisable.

In the first stage of processing, fatty dirt from the belt is removed, the wetting of oxides, soot, etc. is improved, their adhesion to the steel surface is reduced, and their removal is facilitated in the following stages:

Claims (2)

As a wetting agent and emulsifier, a surfactant solution is used - neonol AF 9-12; In the second stage, mechanical impurities in the alkaline solution containing tripolyphosphate sodium are removed from the tape (to improve detergency) and carboxymethylcellulose (to prevent the precipitated impurities from falling back on the steel tape). Sodium hydroxide hydrolyzes the remnants of fatty contaminants, creates an alkaline environment necessary to achieve high detergency and passivation of the steel surface. In the third and fourth stages, the final cleaning of mechanical impurities and an increase in the passivation of the steel surface are carried out in order to obtain a uniform oxide film that ensures good and uniform adhesion of the photoresist in the subsequent stages. The highest purification efficiency is achieved only at the specified sequence of all stages, which is confirmed by the experimental data given in Table. 2. Thus, the use of the proposed method allows the cleaning of steel tape from grease with high efficiency. 8 The invention The method of cleaning metal surfaces from grease, mainly steel tape, including blasting the surface with a heated solution of alkaline components and surfactant substances under mechanical action with brushes, characterized in that, in order to increase the cleaning efficiency, the treatment is first carried out with a solution containing, in wt%: ethoxylated on average 12 moles of ethylene oxide technical isomers of isononylphenol (neonol AF 9-12) 0.03-i, 10, and water - up to 100; then, with a solution containing, by weight: sodium hydroxide, 1.20-3.60; sodium tripolyphosphate, 0.25-0.80; carboxymethylcellulose 0.20-0.60 and water - up to 100; then - with a solution containing, in wt.%: sodium hydroxide 0.80-2.70, disodium salt of ethylenediaminetetraacetic acid (Trilon B) 0.10-0.35 and water g to 100, and then with a solution containing, by weight. %: 0.80-2.70 Sodium hydroxide 0.12-0, ft5 Triethanolamine Ethylenediaminetetraacetic acid disodium salt (Trilon B) 0.10-0.35 Water Lo 100 V Persons 1.2 on three Tripolyphosphate 0,25 sodium Carboxymethyl, 2 Cellulose 98.35 Water to blow Sodium hydroxide Trilon B Water 3.6 0.8 ,, 0-4 0,8 0.9 0.15 0.6 0.15 0.7 98.9 9 95.0 Zo 0, 96.55