Coating and varnish compositions for depositing thin coatings by cathodic electrodeposition

文档序号：1009029 发布日期：2020-10-23 浏览：25次中文

阅读说明：本技术 用阴极电沉积法沉积薄涂层的涂料和清漆组合物 (Coating and varnish compositions for depositing thin coatings by cathodic electrodeposition ) 是由伊莉娜·费奥多罗芙娜·乌特基纳塔特雅纳·尼古拉耶夫纳·玛伊瓦娜杰日达·弗拉基米洛夫娜·提蒙金于 2017-10-04 设计创作，主要内容包括：本发明涉及具有高分散性的水性清漆涂料组合物,其用于通过阴极电沉积方法获得耐化学和耐热涂层。本发明的技术效果是提高了涂层的耐热性、耐盐性和耐水性以及涂层的高耐化学性。用于通过阴极电沉积方法获得薄涂层的清漆组合物包括：浓度为参考标准的36-38％环氧树脂的水性乳液、100％乙酸,2％3-氨基丙基三乙氧基硅烷水溶液,和蒸馏水,具有以下组分比,g/l：环氧树脂水性乳液120-150；100％乙酸0.1-0.6；2％3-氨基丙基三乙氧基硅烷水溶液5-50；加蒸馏水至1升。(The present invention relates to aqueous clear coat coating compositions with high dispersibility for obtaining chemically and thermally resistant coatings by cathodic electrodeposition processes. The invention has the technical effects of improving the heat resistance, salt resistance and water resistance of the coating and high chemical resistance of the coating. A varnish composition for obtaining a thin coating by a cathodic electrodeposition process comprising: an aqueous emulsion of 36-38% epoxy resin at a concentration of reference standard, 100% acetic acid, 2% 3-aminopropyltriethoxysilane in water, and distilled water, having the following composition ratio, g/l: 120-150 of epoxy resin aqueous emulsion; 0.1-0.6% of 100% acetic acid; 5-50% of 2% 3-aminopropyltriethoxysilane aqueous solution; distilled water was added to 1 liter.)

1. A paint and varnish composition for depositing thin coatings using cathodic electrodeposition (electrophoresis) comprising 36% to 38% (d.w.b.) of an aqueous epoxy resin emulsion, 100% acetic acid, 2% aqueous 3-aminopropyltriethoxysilane solution and distilled water, having the following contents, g/L:

aqueous epoxy resin emulsion-120 to 150;

100% acetic acid-0.1 to 0.6;

2% aqueous 3-aminopropyltriethoxysilane solution-5 to 50, and

the distilled water was equilibrated to 1 liter.

2. The coating and varnish composition of claim 1 further comprising from 52 to 56% (d.w.b.) of an aqueous dispersion of a pigment paste stabilized with a low molecular weight epoxy resin at 40 to 47 g/L.

3. The coating and varnish composition of any one of claims 1 or 2, wherein the composition further comprises from 60 to 70% (d.w.b.) of a water-borne fluoroelastomer at 2.5 to 10 g/L.

Technical Field

The invention relates to aqueous dispersions of coating and varnish compositions (polyelectrolytes) having dispersing power, suitable for the deposition of chemically and high temperature resistant coatings by cathodic-electrodeposition (electrophoresis).

Background

The prior art solution presented in patent RU2222563C1, published on 27.1.2004, discloses a composition based on a fluoroplastic and water for depositing a hydrophobic, chemical and abrasion resistant electrophoretic coating, wherein the composition comprises as the fluoroplastic an aqueous dispersion of a fluoroplastic F-40D (Tefzel fluoropolymers from dupont may be used as an analogue), and further comprises an epoxy amine adduct, diethylaminopropylamine and a solution of an epoxy resin in ethyl cellosolve; 100% formic acid; ethoxylated nonyl phenol as stabilizer, and dodecyl ammonium chloride, the contents of the following components, g/L: the adduct-100; 100% formic acid-1.41; aqueous dispersions-250 to 300 of fluoroplastics F-40D; the stabilizer-30 to 50; dodecyl ammonium chloride-7 to 8; water was added to equilibrate to 1 liter.

However, the prior art compositions have the disadvantage of low dispersibility and do not allow the use of the compositions for depositing high quality coatings on complex shaped articles.

The closest prior art solution to the present invention is disclosed in patent RU2437908C1, published 12/27/2011. The proposed coating and varnish compositions comprise epoxy-amine adducts modified with partially blocked toluene diisocyanate as binder; pigment pastes stabilized by the above adducts; 100% acetic acid as a neutralizing agent; butanediol, phenoxypropanol, water, and a fluoroelastomer, having the following content of components, g/L: the adduct-100; pigment paste (100%) -28 to 32; fluororubbers (60 to 70% of dry weight (d.w.b.)) -48 to 52; acetic acid (100%) -0.4; butanediol-3.5 to 4.1; phenoxypropanol-4.5 to 5.1, water was added to equilibrate to 1 liter.

However, a disadvantage of the above-mentioned coating and varnish compositions is the low resistance of the deposited coating to high temperatures.

Disclosure of Invention

The object of the present invention was to develop coating and varnish compositions for the deposition of thin chemically and high temperature resistant coatings using cathodic electrodeposition processes (electrophoresis).

The technical effect of the present invention is that the resistance to high temperature, salt and water is improved due to the high chemical resistance of the coating.

The technical effect is obtained by depositing a thin electrophoretic coating of a paint or varnish composition comprising: a 36-38% aqueous epoxy resin emulsion (d.w.b. on a dry weight basis), 100% acetic acid, 2% aqueous 3-aminopropyltriethoxysilane, and distilled water, having the following content, g/L:

aqueous epoxy resin emulsion-120 to 150;

100% acetic acid-0.1 to 0.6;

2% aqueous 3-aminopropyltriethoxysilane solution-5 to 50, and

the distilled water was equilibrated to 1 liter.

The coating and varnish compositions also comprise an aqueous dispersion of a pigment paste stabilized with a low molecular epoxy resin, in a concentration of 52-56% (d.w.b.) and in an amount of 40-47 g/L.

The coating and varnish compositions also comprise a waterborne fluoroelastomer in a concentration of 60-70% (d.w.b.) in an amount of 2.5-10 g/L.

Detailed Description

The claimed coating and varnish compositions without addition of pigment pastes and aqueous fluoroelastomers were prepared as follows.

A predetermined amount of distilled water (within the desired range) pre-acidified with acetic acid was taken, then mixed with 36% to 38% (d.w.b.) of an aqueous epoxy resin (in the desired range) slowly fed through a fine jet under vigorous stirring (200-500rpm), and then a predetermined amount (within the desired range) of a 2% aqueous solution of 3-aminopropyltriethoxysilane was added.

The claimed coating and varnish compositions with addition of pigment pastes and/or aqueous fluoroelastomers are prepared as follows.

A predetermined amount of distilled water (within the desired range) pre-acidified with acetic acid was taken and mixed with an appropriate amount of 60% to 70% (d.w.b.) aqueous fluoroelastomer under stirring, and then a predetermined amount of 36-38% (d.w.b.) aqueous epoxy resin emulsion (within the desired range) was added under vigorous stirring (200-500 rpm).

In this case, the elastomer particles are further stabilized by the binder and positively charging the fluoroelastomer particles. Further, if desired, the composition can be mixed with a 52% to 56% (d.w.b.) aqueous pigment (the pigment can be any color) slurry dispersion stabilized with a low molecular epoxy resin with stirring, and then the stirring is continued and a predetermined amount (within the desired range)) of a 2% aqueous solution of 3-aminopropyltriethoxysilane is added.

The claimed resultant composition can be used to deposit an electrophoretic coating on any conductive material, including ferrous and non-ferrous metals, powdered metals, semiconductor materials, and conductive plastics. The only changes needed are the deposition mode parameters and the surface preparation method.

To prepare the surface to be coated, it must be degreased (using white spirit, acetone or special detergent compositions, etc.).

The paint is deposited on the surface of the article by immersion in a bath of electrolyte, which is an aqueous solution of the paint and varnish materials. The cell is provided with a mixing system, a working solution temperature control system, an electrodialysis cleaning system and a direct current power supply. The article to be coated is correctly connected as a cathode when immersed in the bath, while the stainless steel plate is connected as an opposite electrode.

The electrophoresis process is as follows: deposition voltage-160 VDC to 250 VDC; deposition time-60 to 180 seconds; working solution temperature-from 30 ℃ to 34 ℃; final coating thickness-from 10 μm to 40 μm. The deposited coating was washed with distilled water and polymerized at 180 ℃ for 30 minutes.

The fluororubber was a copolymer of hexafluoropropylene, tetrafluoroethylene and vinylidene fluoride, and the total fluorine content was 70 wt%.

The epoxy resin is used as the main component of the composition, so that the basic performance of the coating is provided, and the salt resistance and the water resistance are improved; the addition of the pigment slurry enables the film to be colored, and the hardness, salt resistance and water resistance are improved; fluoroelastomers provide the necessary level of chemical resistance; the aminopropyltriethoxysilane improves high temperature resistance, chemical resistance and water resistance; finally, acetic acid is an epoxy resin neutralizer that ensures the acidity of the solution.

Examples of the claimed coating and varnish compositions are given in table 1, tables 2, 3, 4 and 5 show the properties of the coatings deposited on 08KP grade steel (structural quality carbon steel) according to the above examples of the claimed coating and varnish compositions, and tables 6, 7, 8 and 9 show the properties on p-type semiconductor thermoelectric materials (Bi)₂Te₂)_х(Sb₂Te)_1-xAnd (Bi)₂Te₃)_х(Sb₂Te₃)_y(Sb₂Se₃)_1-y-xAnd n-type semiconductor thermoelectric material (Bi)₂Se₃)_x(Bi₂Te₃)_1-xThe same coating deposited thereon.

The invention has been disclosed above with reference to specific embodiments. Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification, which do not depart from the essence thereof. Accordingly, the scope of the invention should be considered limited only by the attached claims.

TABLE 1