WO1999046425A1

WO1999046425A1 - Agent for cleaning metal and metal-containing surfaces

Info

Publication number: WO1999046425A1
Application number: PCT/RU1998/000072
Authority: WO
Inventors: Dmitry Leonidovich Tjutjunnikov
Original assignee: Zakrytoe Aktsionernoe Obschestvo Firma Novye Sistemnye Teknologii
Priority date: 1998-03-13
Filing date: 1998-03-13
Publication date: 1999-09-16
Also published as: AU8467798A

Abstract

Invention pertains to agents for chemical treatment of metal and metal-containing surfaces for the purpose of removing rust and corrosion products, and it may be used in various branches for preparation of surfaces prior to painting, priming or application of protective coatings, and it is defined as agent for cleaning metal and metal-containing surfaces in a form of gel containing rust-preventive and auxiliary components at the following ratio, including: rust-preventing component 250-:-400; water glass 50-:-150; colloid stabilizer 5-:-10; colorant-indicator (methylene blue) 0.02-:-0.1; water 300-:-700. As compared with known rust-preventive agents the proposed cleaning gel features improved adhesion, does not contain toxic components, allows efficient and even cleaning of surfaces of sophisticated configuration and expectant utilization of waste.

Description

Agent for cleaning metal and metal-containing surfaces.

Field of the invention.

The invention pertains to agents for chemical treatment of metal and metal-containing surfaces for the purpose of removing rust and corrosion products, and it may be used in various branches for preparation of surfaces prior to painting, priming or application of protective coatings.

Backgraund of the invention.

Known is acid rust cleaning agent for rust designated for removal of corrosion products from metal surfaces prior application or painting based on orthophosphoric acid, monosubstituted copper orthophosphate, thiourea and surfactant (certificate of authorship, USSA.No. 1468968, cl. C23 G 1/10).

This composition is targeted for long treatment of surfaces at rather high temperature and is efficient basically for ferromagnetics.

The closest in technical essence and functional designation to the proposed agent is pickling paste based on rust-preventing component: hydrochloric or orthophosphoric acid used for removing scale and corrosion products from large-size parts. (S. Ya. Grilihess., Polishing, pickling and degreasing of metals., L., Machine-building, 1971, p.74).

2-3 cm layers of picking paste are applied on the metal surface and are allowed to stand during 0.5 - 3 hours, then it is washed off by water spraying and passivated by sodium nitrate. Composition of pickling paste in 1 1 is as below:

Hydrochloric acid (density 1.19) 300 - 350 ml

Sulfate cellulose liquor 50 ml

Urotropin (hexamethylenetetramine) 7g/l

Nekal (sodium dibutylnaphthalenesulfonate) 5 g/1

Crushed asbestos up to 300 g/1

Water the rest

Despite introduction of a big quantity of filler - crushed asbestos, pickling paste is rather fluid this resulting in high consumption of the product and lower efficiency of the cleaning of vertical surfaces of structures.

Another grave drawback of paste is just the presence of insoluble component that in addition is extremely harmful to health, and as a result, uneven cleaning and insufficient removal of cleaning agent. For instance, when treating surfaces of sophisticated configuration insoluble filler particles in some sections "stick to" the surface and can be removed only mechanically. Of no lesser problem is utilization of harmful waste.

Summary of the invention. Detaild description of the invention.

The object of invention makes possible agent for cleaning metal and metal-containing surfaces that features improved adhesion, does not contain harmful components allowing achievement of efficient and even cleaning of surfaces with sophisticated configuration and expectant easy utilization of waste.

Proposed is agent for cleaning metal and metal-containing surfaces with rust-preventing and auxiliary components that is defined as gel and that contains, as auxiliary components, water glass, colloid stabilizer, colorant-indicator and water with the following ratio of components, including: Rust-preventing component 250 -: - 400;

Water glass 50 -: - 150;

Colloid stabilizer 5 -: - 10;

Colorant-indicator 0.02 -: - 0.1 ;

Water 300 -: - 700

Depending on the field of application of agent acids, mainly, from phosphoric series or hydrochloric acid in combination with urotropin at ratio, accordingly, (45 - 55): 1, are used as a rust-preventing component.

As colloid base sodium or potassium water glass is used.

For stabilization of the colloid system sodium or potassium hydrolyzed salt of carboxyalkyl celluloses, mainly, of carboxymethyl celluloses (CMC) are used.

Sodium salt of CMC introduced in agent is widely used in the petroleum and textile industries. In particular, when used in the petroleum industry at the cost of introducing CMC solution stabilization of clayey suspensions through formation of structurized protective film is taking place. In the textile industry it is used as thickener for printing dyes.

However, application in the above mentioned areas does not make origination of new CMC properties apparent that are realized in combination with water glass and other components in the proposed composition. It should be noted that stability of homogeneous structurized colloid formed in acid medium by gel-producing water glass is caused by introduction of strictly specified quantity of CMC, hindering such undesirable phenomena as syneresis, i.e. spontaneous reduction of gel volume accompanied by separation of liquid phase.

Practically any colorant can be selected from a series of chemically acceptable colorants. It serves primarily as indicator of gel "depletion", though its inclusion in gel composition does not rule out aesthetic considerations, as well. By means of colorant we can control visually the degree of gel neutralization through changes in color of cleaning agent. 4

In some cases small quantity of weak organic acid (oxalic acid, citric acid etc.) can be introduced into composition.

Method of agent preparation.

Example 1.

In a separate reactor solution of carboxymethyl cellulose is prepared by diluting it with water to concentration 30-40 g/1, then mass is kept to stand for at least 3 days with continuous mixing till complete dissolution for transforming CMC into hydrolyzed form.

Hydrolyzed CMC is loaded into another reactor with orthophosphoric acid pre-diluted in water at ratio 3:1 and then while continuing the mixing add water glass and colorant diluted in water at ratio 1:1.

During 2-3 hours the resultant mass retains the properties of ordinary liquid and then it transforms into gel ready for practical use.

Finished product is light pink (when methyl orange is used as colorant-indicator) colloid mass (jelly) without solid particles or non-uniform inclusions.

Example 2

Hydrolyzed CMC is loaded into another reactor with hydrochloric acid pre-diluted in water at ratio 1:1 with addition of the required quantity of urotropin (hexamethylenetetramine) and while continuing the mixing add water glass and colorant diluted in water.

During 2-3 hours the resultant mass retains the properties of ordinary liquid and then it transforms into gel ready for practical use. Finished product is light green (when methylene blue is used as colorant-indicator) colloid mass (jelly) without solid particles or non-uniform inclusions.

Examples below illustrate alternative compositions of gel-cleaning agent.

Example 3.

rust-preventing component

(orthophosphoric acid) 250 water glass 80 colloid stabilizer (CMC) 10 colorant-indicator (methyl orange) 0.04 water 400

Example 4.

rust-preventing component

(orthophosphoric acid) 400 water glass 150 colloid stabilizer (CMC) 5 colorant-indicator (methyl orange) 0.1 water 300

Example 5.

rust-preventing component

(orthophosphoric acid) 350 water glass 100 colloid stabilizer (CMC) 8 colorant-indicator (methyl orange) 0.02 water 600 Example 6.

rust-preventing component

(hydrochloric acid + urotropin, 47:1) 350 water glass 100 colloid stabilizer (CMC) 8 colorant-indicator (methylene blue) 0.02 water 600

Example 7.

rust-preventing component

(hydrochloric acid + urotropin, 47:1) 400 water glass 150 colloid stabilizer (CMC) 5 colorant-indicator (methylene blue) 0.1 water 300

Example 8.

rust-preventing component

(hydrochloric acid + urotropin, 47: 1) 250 water glass 80 colloid stabilizer (CMC) 10 colorant-indicator (methylene blue) 0.04 water 400

Example 9.

rust-preventing component

(orthophosphoric acid) 250 oxalic acid 40 water glass 90 colloid stabilizer (CMC) 10 colorant-indicator (methyl orange) 0.04 water 400

Example 10.

Method of the use of gel for rust removal.

Loose rust and rust layer having been removed, 1-3 cm layer of gel is put on corrosion hit surface and keep to stand for 10-30 min.

After holding treated gel is washed off by water solution of detergent or by water.

Example 11.

Method of the use of gel for formation of protective film.

For this purpose gel with orthophosphoric acid as a rust-preventive component is used.

1-3 cm layer of gel is put on the preliminary cleaned and degreased surface, kept to stand for 1.5-2.0 hours, stippling it at regular periods and not allowing to dry. After washing the surface is dried. Upon complete drying up the surface can be primed or painted.

Since the proposed agent has the widest application in treatment of Fe-containing surfaces experiments were mainly performed on steels and pig irons of various grades. At the same time gel under test was equally well efficient for treatment of surfaces with Cu-, Ni, Cr- containing alloys (brass, bronze and the like). Precautions for work with gel

Despite relative safety of gel it is desirable to perform all operations in rubber gloves; after contact of gel with skin it should be washed off by water.

Tables 1 and 2 demonstrate the results of comparative tests of proposed gel-cleaning agent and the known agent, pickling paste.

Tests were performed on the similarly prepared surfaces with similar degree of corrosion affection.

Table 1

Agent under test Cleaning time, Cleaning efficiency, % hour

Level of technology: 0.5 72% pickling paste re-treatment is required

Gel as per example 3. 0.5 98%

Gel as per example 4. 0.5 100%

Gel as per example 5. 0.5 100%

Gel as per example 6. 0.5 100%

Gel as per example 7. 0.5 100%

Gel as per example 8. 0.5 98%

Gel as per example 9. 0.5 100%

Table 2.

Agent under test Cleaning time, Cleaning efficiency, % hour

Level of technology: 97% pickling paste 1.0 re-treatment is required

Gel as per example 3. 1.0 100%

Gel as per example 4. 1.0 100%

Gel as per example 5. 1.0 100%

Gel as per example 6. 1.0 100%

Gel as per example 7. 1.0 100%

Gel as per example 8. 1.0 100%

Gel as per example 9. 1.0 100%

The Tables above show that the proposed rust cleaning gel, as a minimum, is not inferior to well-known pickling paste in its basic parameter, rust-preventive activity.

Gel-cleaning agent that features high adhesion allows its use on surfaces of the most sophisticated configuration, in particular, it sticks well to vertical surfaces. The product is practically non-toxic this allowing cleaning and preparation of surfaces not only at works but at home, as well.

Absence of hard inclusions pre-determines even cleaning.

Complete dissolubility in water does not make problems with utilization of spent product. Presence of colorant-indicator in agent facilitates control over gel status in the process of work.

The product has rather long shelf-life retaining its consumer properties.

All the above enumerated properties of the proposed agent allows applications in various branches of industry where efficient and qualitative preparation of metal surfaces of various configurations for subsequent protection or paining of articles is required.

Claims

10Claims.

1. Agent for cleaning metal and metal-containing surfaces containing rust-preventive and auxiliary components, characterized in that, it is gel and as auxiliary components contains water glass, colloid stabilizer, colorant-indicator and water at the following ratio of components, including:

rust-preventing component 250 -: -400 water glass 50 -: - 150 colloid stabilizer 5 -: -10 colorant-indicator (methylene blue) 0.02-: -0.1 water 300 -: -700

2. Agent as per claim 1, characterized in that it contains sodium or potassium hydrolyzed salt of carboxyalkyl cellulose as colloid stabilizer.

3. Agent as per claims 1, 2, characterized in that it contains sodium hydrolyzed salt of carboxymethyl cellulose as colloid stabilizer.

4. Agent as per claim 1, characterized in that it contains orthophosphoric acid as a rust-preventive component.

5. Agent as per claim 1, characterized in that it contains mix of hydrochloric acid and urotropin as a rust-preventive component.

6. Agent as per claims 1, 4, characterized in that it contains methyl orange as colorant-indicator.

7. Agent as per claim 1, 5, characterized in that it contains "methylene blue" as colorant- indicator.

8. Agent as per claim 4, characterized in that it contains as an addition weak organic acid.