RU2405013C1 - Protective lacquer composition and method of applying protective coating on waveguide devices made from aluminium alloys having complex shape - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: protective lacquer composition for devices made from aluminium alloys based on KC-0125 lacquer contains 68±2% solution in diacetone and isopropyl alcohol of maleinised polybutadiene, modified with phenol resin with addition of 25% aqueous ammonia and a mixture of isopropyl alcohol and water in ratio of 1:1 and acrylic copolymer with pH of the composition equal to 6.5-7.5. The method of applying a protective coating onto waveguide devices made from aluminium alloys having a complex shape is realised by preparing the surface by etching, washing in flowing hot water, washing in flowing cold water, clarification, washing in flowing cold water, chemical oxidation, washing in flowing cold water, removing condensed moisture, chemical cleaning and washing in flowing cold water. Said lacquer composition is then applied by simple immersion for 3-5 minutes at 15-35°C and washing in flowing cold water. The lacquer coating is deposited in a solution containing linoleic acid, oxalic acid, mixture of isopropyl alcohol and water in ratio of 1:1 and then washing in flowing cold water, removing condensed moisture and curing at 110-120°C for not less than 30 minutes.

EFFECT: obtaining a protective lacquer coating which can form a non-porous, corrosion-resistant coating on the surface of oxidised aluminium alloys with reduction of hardening temperature of the composition.

2 cl, 3 ex

Description

The invention relates to a lacquer protective composition and a method for producing a lacquer protective coating on complex-shaped waveguides made of aluminum alloys and can be used in the radio engineering industry, instrumentation, aircraft industry and in other areas of the national economy for products operated in various climatic conditions.

In modern technology, a water-borne lacquer composition for anticorrosive protection of aluminum alloys is known [RF Patent No. 2230762, publ. June 20, 2004], consisting of:

Varnish KCh-0125 50-100 g / l Ammonia water 25% solution 3-6 ml / l A mixture of isopropyl alcohol and water (1: 1) Up to 1 liter pH of the composition 6.5-7.2

and the method of applying it includes the following operations: etching, washing in hot running water, washing in cold running water, clarification, washing in cold running water, chemical oxidation, washing in cold running water, removing droplet moisture, chemical degreasing, washing in cold running water, applying the lacquer composition by simple immersion for 2-4 minutes, removing from the composition, immersion in a solution to activate the composition

Phosphoric acid 1.0 ml / l Substance auxiliary OP-7 or OP-10 10.0 g / l

for 1-3 minutes at a temperature of 15-35 ° C, removing from the activation solution, re-immersion in the varnish composition, washing in cold running water, removing droplet moisture and thermosetting at a temperature of 125-180 ° C for at least 1 hour.

The closest in technical essence to the proposed composition is a composition [Patent No. 2304157. published on August 10, 2007] based on KCH-0125 varnish, which is a 68 ± 2% solution of maleated polybutadiene in isopropyl and diacetone alcohol modified with phenolic resin with the addition of 25% aqueous ammonia and a mixture of isopropyl alcohol and water in 1: 1 ratio with the following ratio of components:

Varnish KCh-0125 70-120 g / l Ammonia water (25% solution) 4-7 ml / l A mixture of isopropyl alcohol and water (1: 1) Up to 1 liter pH of the composition 6.5-7.5

and a method of obtaining a protective coating on complex waveguides made of aluminum alloys includes etching, washing in hot running water, washing in cold running water, clarification, washing in cold running water, chemical oxidation, washing in cold running water, removing droplet moisture, chemical degreasing , applying the varnish composition by simple immersion for 2-4 minutes at a temperature of 15-35 ° C, washing in cold running water, fixing the varnish in a solution of the composition:

Linoleic acid 3 ml / l Oxalic acid 3 g / l A mixture of isopropyl alcohol and water Up to 1 liter

A mixture of isopropyl alcohol and water

in the ratio 1: 1 Up to 1 liter

washing in cold running water, removing droplet moisture and curing at a temperature of 120-130 ° C for at least 30 minutes

This method does not allow to obtain on the surface of complex products from aluminum alloys a non-porous coating uniform in thickness with good adhesion.

An object of the invention is to obtain a protective varnish composition capable of forming a non-porous, corrosion-resistant coating on the surface of oxidized aluminum alloys while lowering the curing temperature of the composition.

The solution to the problem is achieved by the fact that the lacquer composition for aluminum alloy products based on lacquer KCH-0125 (TU 2313-034-00204151-200), which is a 68 ± 2% solution of maleated polybutadiene modified with phenolic resin with diacetone and isopropyl alcohol, is added aqueous ammonia 25% (GOST 24147-80) and a mixture of isopropyl alcohol (GOST 9805-84) and water in a ratio of 1: 1.

New in the proposed composition is the introduction into the varnish composition of an acrylic copolymer (TU 2216-001-47228584) with the following ratio of components:

Varnish KCh-0125 170-220 g / l Ammonia water (25% solution) 0.9-1.0 ml / l Acrylic copolymer 3.0-4.0 g / l A mixture of isopropyl alcohol and water (1: 1) Up to 1 liter pH of the composition 6.5-7.5

As an acrylic copolymer, either Lacryl AC - the product of the polymerization of methacrylic and acrylic esters, styrene (TU 2216-002-51764779-2000), or Lacryl M - the product of the copolymerization of methacrylic esters (TU 2216-001-47-228584-99) can be used or BMK 5 is the product of the copolymerization of methacrylic acid and its ether (TU 2216-518-00208947-2009).

A method of obtaining a protective coating for complex waveguide devices made of aluminum alloys based on etching, washing in hot running water, washing in cold running water, clarification, washing in cold running water, chemical oxidation, washing in cold running water, removing droplet moisture, chemical degreasing, washing in cold running water, applying the varnish composition according to claim 1 by simple immersion for 3-5 minutes at a temperature of 15-35 ° C, washing in cold running water, fixing What are the coating composition in solution:

Linoleic acid 3 ml / l Oxalic acid 3 g / l A mixture of isopropyl alcohol and water in the ratio (1: 1) Up to 1 liter

washing in cold running water, removing droplet moisture and thermosetting at a temperature of (110 ... 120) ° С for at least 30 minutes.

Example 1

The corrosion protection of aluminum alloy products was carried out with a gap between the oxidation and varnishing operation of 30 days with the following application method:

1. Surface preparation:

- etching, for example in a solution of NaOH;

- flushing in hot running water;

- flushing in cold running water;

- clarification, for example in a solution of HNO ₃ ;

- flushing in cold running water;

- chemical oxidation, for example in a solution of the composition, g / l:

Phosphoric acid 40-50 Chromic anhydride 5-7 Sodium Fluoride 3-4,

- flushing in cold running water;

- removal of drip moisture, for example, compressed air;

- chemical degreasing, for example in a solution of an auxiliary substance OP-10;

- flushing in cold running water.

2. Application of the varnish film by simple immersion in the varnish composition of the following composition:

Varnish KCh-0125 170 g / l Ammonia water (25% solution) 0.9 ml / l Acrylic copolymer 3.0 g / l A mixture of isopropyl alcohol and water (1: 1) Up to 1 liter pH of the composition 6.5

for 3 min at a temperature of 15 ° C;

- flushing in cold running water;

- fixing the varnish coating in a solution of the following composition:

Linoleic acid 3 ml / l Oxalic acid 3 g / l A mixture of isopropyl alcohol and water in a ratio of 1: 1 Up to 1 liter

- flushing in cold running water;

- removal of drip moisture, for example by blowing.

3. Curing at a temperature of 110 ° C for 60 minutes.

Received a low-porous, benign in appearance coating, firmly adhered to the aluminum base.

These parts were tested for cyclic exposure to temperatures from -60 ° C to 85 ° C (3 cycles), exposure to tropical humidity for 12 days (relative humidity 98 ± 2% at 40 ° C) and sea fog for 7 days.

After testing, the appearance of the varnish film remained unchanged, aluminum corrosion was not detected.

Example 2

Corrosion protection was carried out by the proposed composition of waveguide structures with a channel section of 13 × 3 at a length of 500 mm from aluminum alloys according to the following mode:

1. Surface preparation (example 1).

2. The application of the varnish film was carried out for 4 min according to example 1 in the composition:

Varnish KCh-0125 200 g / l Ammonia water (25% solution) 1.0 ml / l Acrylic copolymer 3.5 g / l A mixture of isopropyl alcohol and water (1: 1) Up to 1 liter pH of the composition 7.0

3. Curing at 115 ° C for 45 minutes.

Received a low-porous, benign in appearance coating, firmly adhered to the aluminum base. After testing for exposure to high humidity and sea fog (example 1), the appearance of the varnish film remained unchanged. Corrosion on aluminum alloys and on the coating was not observed.

Example 3

The corrosion protection of aluminum alloy products was carried out according to the following technological scheme:

1. Surface preparation (example 1);

2. The application of the varnish film was carried out for 5 min according to example 1 in the composition:

Varnish KCh-0125 220 g / l Ammonia water (25% solution) 1.0 ml / l Acrylic copolymer 4.0 g / l A mixture of isopropyl alcohol and water (1: 1) Up to 1 liter pH of the composition 7.5

3. Curing at a temperature of (120) ° C for 30 minutes.

Received a low porous, corrosion resistant coating.

After testing for exposure to high humidity and sea fog (example 1), the appearance of the varnish film remained unchanged. Corrosion on aluminum alloys and on the coating was not observed.

Claims (2)

1. Protective varnish composition for devices made of aluminum alloys based on varnish КЧ-0125, which is a (68 ± 2)% solution of maleated polybutadiene modified with phenolic resin with 25% aqueous ammonia and an isopropyl mixture in diacetone and isopropyl alcohol alcohol and water in a ratio of 1: 1, characterized in that it further comprises an acrylic copolymer in the following ratio of components:
Varnish KCh-0125 170-220 g / l Ammonia water (25% solution) 0.9-1.0 ml / l Acrylic copolymer 3.0-4.0 g / l A mixture of isopropyl alcohol and water (1: 1) up to 1 l pH of the composition 6.5-7.5 2. A method of obtaining a protective coating for complex waveguide devices made of aluminum alloys based on etching, washing in hot running water, washing in cold running water, clarification, washing in cold running water, chemical oxidation, washing in cold running water, removing droplet moisture , chemical degreasing, washing in cold running water, applying the varnish composition according to claim 1 by simple immersion for 3-5 minutes at a temperature of 15-35 ° C, washing in cold running water, fixing l aka coating in a solution of the composition:
Linoleic acid 3 ml / l Oxalic acid 3 g / l A mixture of isopropyl alcohol and water (1: 1) up to 1 l
washing in cold running water, removing droplet moisture and thermosetting at a temperature of 110 ... 120 ° C for at least 30 minutes.