RU2145970C1 - Composition for anodic electrodeposition - Google Patents

Abstract

FIELD: electronic, radio engineering, aircraft, automotive and machine building industries, more particularly preparation of decorative coatings for consumer goods. SUBSTANCE: described is composition for anodic electrodeposition which comprises, wt.%: water diluted varnish based on film-forming agent selected from product of maleinization of low-molecular cis-polybutadiene rubber and phenol-formaldehyde rosin and dehydrated castor oil modified with resin in organic solvents, 12.3- 15.4; water-insoluble organic colorant selected from group consisting of yellow dispersive colorant, scarlet dispersive colorant, red dispersive colorant and metallophthalocyanine colorant wherein M is Cu, Co, Ni, Fe, 0.05-0.4; neutralizer which is triethyl amine or 25-% aqueous ammonia solution, 0.9-1.1; distilled water, the balance. EFFECT: high sedimentation resistance and reduced energy capacity, good physico-mechanical and physico-chemical properties at lower solidification temperatures and wider spectrum of colors of coatings. 9 ex, 2 tbl

Description

 The invention relates to the field of producing colored, transparent organic coatings applied by anodic electrodeposition on conductive surfaces and can be used in electronic, radio engineering, aviation, automobile industry, mechanical engineering, to obtain decorative coatings in the production of consumer goods, etc.

 Known compositions for anode electrodeposition based on primers VAU-0118 / VTU LF 7-11-72 / and VAU-0150 / TU 6-10-1599-77 /. Primers are a suspension of pigments / various combinations of pigments depending on the color of the primer: titanium white, strontium chromate, aluminosilicate pigment, lead silico chromate, carbon black, iron oxide pigments / in water-borne film former VUPFS-35 / VTU NCh-7-11-72 / a pentaphthalic soybean oil oligomer modified with isocyanates blocked by allyl alcohol.

 The disadvantage of analogues is the low sedimentation stability of their aqueous suspensions, very limited color gamut / mostly red-brown and gray /. This is due to the extremely narrow range of pigments suitable for use in water-borne materials for electrodeposition, which is due to stringent requirements for them: chemical inertness and purity / complete absence of water-soluble impurities /, high dispersion and easy dispersibility, high opacity, etc.

 The process of manufacturing primers is quite long, laborious and energy intensive, including the stages of kneading the film former with pigment followed by long-term dispersion of the pigment paste on various kinds of dispersing devices, standardization by color and other indicators, filtration and packaging.

The closest analogue is a composition for anode electrodeposition based on water-borne primers VKCh-0207 / TU-6-10-1654-83 / or VKF-093 / OST 6-10-427-79 /, containing, wt.%:
Water-borne primer - 15.0 - 17.0
including:
waterborne varnish / C.O. = 64 ± 1 / - 7.5 - 8.5
organic solvent - 4.1 - 4.6
pigment - 3.4 - 3.9
Triethylamine or 25% aqueous ammonia - 0.85 - 0.95
Distilled Water - Else
The composition of the varnish KCH-0125, on the basis of which the primer VKCh-0207 is made, as well as the composition of the varnish VA-133 for the primer VKF-093 are given below:
The composition of the varnish KCH-0125, wt.%:
Maleinized low molecular weight polybutadiene rubber - 43.85
Phenol-formaldehyde resin ZVA-194 - 31.21
Ionol / antioxidant / - 1.21
Isopropyl alcohol - 16.00
Diacetone alcohol - 4.40
50% solution of triethylamine in isopropyl alcohol - 3.33
The composition of the varnish VA-133, wt.%:
Dehydrated Castor Oil - 35.92
Flaxseed oil - 6.59
Glycerin - 1.58
Rosin - 10.41
Maleic anhydride - 10.50
Distilled Water - 3.15
Diacetone alcohol - 0.52
Isopropyl alcohol - 30.60
Ionol - 0.52
As inorganic pigments in both primers / VKF-093 and VKCh-0207 /, pigments such as titanium white / rutile /, lead silico-chromate, aluminosilicate pigment, carbon black are used.

 To prepare working compositions, the required amount of a neutralizer, triethylamine or a 25% aqueous ammonia solution, is added to the primer VKCh-0207 / or VKF-093 /, the mass is mixed until homogeneous, and then distilled water is added with continuous stirring to obtain the required solution concentrations. The composition is stirred for 4-6 hours, after which it is monitored for compliance with the requirements of the standard: pH, solids, temperature.

The staining process is carried out on a pre-fat-free conductive surface of the product for 1.5-2.0 minutes at a voltage of 150-300 V. After that, the product is removed from the paint bath, washed with water and cured at a temperature of 180 ^o C for 30 minutes.

The disadvantages of the prototype are low sedimentation stability of the composition, requiring intensive forced mixing, low working capacity / especially in conditions of periodic operation / composition, extremely limited color gamut of coatings / only gray, black and red-brown colors / and high curing temperature of coatings. When lowering the curing temperature below 180 ^o C even when the curing time is increased by 2-3 times, it is impossible to obtain coatings with good protective properties.

 SUMMARY OF THE INVENTION

 The inventive task was to develop a composition for anodic electrodeposition, which has high sedimentation stability and performance, which allows to obtain coatings with good physicomechanical and physicochemical properties at lower curing temperatures, as well as a significant expansion of the color range of coatings.

According to the invention, there is provided a composition for anodic electrodeposition, comprising a water-borne varnish, a coloring component, a triethylamine neutralizer or a 25% aqueous ammonia solution and distilled water, and characterized in that as a water-borne varnish it contains a varnish based on a film former selected from the group the product of maleinization of low molecular weight cis-polybutadiene rubber and phenol-formaldehyde resin or the product of maleinization of a copolymer of linseed and dehydrated castor oils, my differentiated with rosin, in organic solvents, and as a coloring component - a water-insoluble organic dye selected from the group consisting of dispersed yellow dye D, dispersed red W, dispersed red 2C and metallophthalocyanine dye, in the following ratio, wt.%:
Water-borne varnish based on a film former selected from the group of maleinization product of low molecular weight cis-polybutadiene rubber and phenol-formaldehyde resin or maleinization product of a copolymer of linseed and dehydrated castor oil modified with rosin in organic solvents - 12.3 - 15.4
A water-insoluble organic dye selected from the group consisting of a dispersed yellow dye D, dispersed red W, dispersed red 2C and a metallophthalocyanine dye, where the metal is Cu, Co, Ni, Fe - 0.05 - 0.4
Neutralizer-triethylamine or 25% aqueous ammonia - 0.9 - 1.1
Distilled Water - Else
All coloring components are finely divided powders painted in a characteristic color.

 As a water-borne varnish can be used film former VKCh-0125 / TU-6-10-200-218-79 / or rezidrol VA-133 / TU-6-10-1705-79 /. Lacquer VKCH-0125 is a product of maleinization of low molecular weight cis-polybutadiene rubber SKDN-N with the addition of phenol-formaldehyde resin FL-0142 / TU-6-10-1804-81 / representing resolcarboxylic acid cocondensate / product of the treatment of diphenylolpropane with monochloracetic acid / diphenylolpropane medium / ethanol.

 Residrol VA-133 is a product of maleinization of a copolymer of linseed and dehydrated castor oils, modified with rosin.

 Available in the form of a solution in isopropyl, diacetone alcohols with a content of non-volatile substances 64 ± 1%.

 Only in the presence of the totality of the essential features of the claimed invention is it possible to achieve the specified technical result. With going beyond the declared intervals of the content of components to a greater or lesser extent, a deterioration in the appearance of coatings or a decrease in the physicomechanical or physicochemical properties of the coatings is observed.

 The implementation of the invention.

Example 1. In the container for preparing the composition is loaded varnish KCH-0125 / solids content of 65 wt.% / - 12.3 and an organic dye of 0.05 g. The mixture is stirred until uniform for 20 to 30 minutes, after which it is added triethylamine 0.9 g / 1.2 ml /, after which stirring is continued for another 15 to 20 minutes, then with continuous stirring, distilled water of 86.75 g / ml / is introduced into the neutralized mass. At the initial moment, water is introduced in small portions, then after the introduction of about a third of the total amount of water, the remaining amount of water is loaded into the mass. Stirring is continued for 2-3 hours until a homogeneous solution is formed (sample on glass), then the composition is filtered and checked for compliance with the following indicators:
1. The dry residue, wt.% 8-10
2. The pH of the composition is 6.8-7.3
3. Temperature, ^o C 18-24
Examples with other claimed quantitative values of the components are presented in table. 1.

The prepared compositions are poured into the electrodeposition bath made of stainless steel and which is the anode, the product to be painted is loaded into the bath and painted at a voltage of 50-250 V for 1-2 minutes. After painting, the product is removed from the bath, washed with water and dried at temperatures of 130 - 180 ^o C for 15-90 minutes

 Quality control of coatings is carried out according to their appearance, protective properties, hardness one day after their curing.

 The appearance of the coatings is evaluated visually.

 The protective properties of the coatings are controlled using the following methods.

1. Moisture resistance is determined in the hydrostat G-4. The cycle is the exposure of samples at a temperature of 38 - 42 ^o C and relative humidity for 12 hours. After this, exposure is followed for 12 hours at a temperature of 18 - 22 ^o C at the same relative humidity.

2. Alkali resistance is determined in a 10% aqueous KOH solution at a temperature of 18 - 20 ^o C. The coated sample / with insulated edges / is connected anode to a DC source at a voltage of 25 V. The moment of destruction of the coating is considered to be the density of the current passing through the sample , values of 0.1 mA / cm ² .

 3. Alcohol-benzene resistance was determined in an alcohol-gasoline mixture / 1: 1 / with simultaneous exposure to a colored sample of ultrasound with a frequency of 18 - 20 kHz.

 4. The hardness of the coatings is estimated by the pencil "Designer".

 5. Sedimentation stability.

 During long interruptions in the operation of the electrodeposition baths, a precipitate consisting of pigments and an adsorbed film former falls to the bottom.

 The sedimentation stability of the compositions / based on the primer VKCh-0207 and the proposed / is estimated by the time of their forced mixing, necessary to transfer the stratified composition into a state uniform throughout the volume of the bath. After this, the composition can be used for dyeing products.

 The test results presented in table. 2, indicate that when staining products from the proposed compositions can be obtained coatings of various colors.

The temperature range of curing coatings is in the range 130-180 ^o C, while coatings from the primer VKCH-0207 cure at 180-200 ^o C.

Physico-mechanical and physico-chemical properties of the coatings of the proposed compositions, cured according to any one of the tab. 2 modes are at the level of the corresponding parameters of the prototype, cured according to the standard, guest mode / 180 ^o C, 30 min or 200 ^o C - 15 min / or surpass them.

The curing of coatings from the primer VKCH-0207 / prototype / at 130 ^o C and 150 ^o C for 90 minutes does not allow to obtain coatings with good performance properties. Pencil hardness "Designer" does not rise above the value of "M" or "TM". The physicochemical properties of the coatings — alcohol and benzene resistance and alkali resistance — are inferior to coatings of the proposed compositions.

Lowering the curing temperature of the coatings of the proposed compositions can significantly expand their field of use. This is especially true when painting products made of aluminum and its alloys, since at temperatures above 140-150 ^o C may be a deterioration in their structural properties, as well as melting of low-temperature solders used in the manufacture of products.

 Lowering the curing temperature allows you to get lighter tones of the coatings, thereby contributing to the expansion of their areas of use, which is important when obtaining decorative coatings, for example, on consumer goods.

Claims (1)

Composition for anodic electrodeposition, including a water-borne varnish, a coloring component, a neutralizer - triethylamine or 25% aqueous ammonia solution and distilled water, characterized in that as a water-borne varnish it contains a varnish based on a film former selected from the low molecular weight cis- maleinization product group polybutadiene rubber and phenol-formaldehyde resin or maleization product of a copolymer of linseed and dehydrated castor oil, modified with rosin, in organic solvents, and as a coloring component, a water-insoluble organic dye selected from the group consisting of dispersed yellow D dye, dispersed red D dye, dispersed red 2C dye and metallophthalocyanine dye, where the metal is Cu, Co, Ni, Fe, in the following ratio of components , wt.%:
Water-borne varnish based on a film former selected from the group of maleinization product of low molecular weight cis-polybutadiene rubber and phenol-formaldehyde resin or maleinization product of a copolymer of linseed and dehydrated castor oil modified with rosin in organic solvents - 12.3 - 15.4
A water-insoluble organic dye selected from the group consisting of dispersed yellow 3 dye,
dispersed scarlet Zh, dispersed red 2C and metallophthalocyanine dye, where the metal is Cu, Co, Ni, Fe - 0.05 - 0.4
The neutralizer is triethylamine or a 25% aqueous solution of ammonia - 0.9 - 1.1
Distilled Water - Else

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