Ultrahigh-thickness film type cathode electrophoretic coating

Abstract

The invention discloses an ultra-high thick film type cathode electrophoretic coating which comprises color paste and an emulsion, the color paste is prepared by taking thermal expansion microspheres as a filler of quaternary ammonium salt or tertiary amine salt grinding resin, adding carbon black, a dispersing agent, a defoaming agent, pure water and lactic acid, and controlling the grinding process temperature in a grinding manner; the emulsion is a universal emulsion. According to the ultra-high thick film type cathode electrophoretic coating provided by the invention, by utilizing the characteristic that the volume of the thermal expansion microspheres is expanded and amplified by several times or dozens of times after the thermal expansion microspheres are heated, the film thickness of an electrophoretic coating film is remarkably increased in the baking process so as to achieve the effect of an ultra-thick film, and the thick film effect is brought by the volume expansion and amplification of the thermal expansion microspheres, so that the thickness of the electrophoretic coating film is greatly increased in the using process. And the use cost is not increased due to the increase of the thickness of the paint film. Meanwhile, the expansion microspheres are of hollow core-shell structures and have good resistance, so that the product has very excellent throwing power and can be used in various workpiece products with complex inner cavities.

Description

Technical Field

[0001] The invention relates to the technical field of cathode electrophoretic coatings, and in particular to an ultra-high thick film type cathode electrophoretic coating. Background Art

[0002] Since electrophoretic coatings were introduced as new coatings, they have been widely used in the automotive, hardware, and home appliance industries, replacing powder coatings and spray coatings, due to their advantages in environmental protection, coating efficiency, and coating complex workpieces. Some special fields require ultra-thick film coatings, such as a film thickness of more than 100um, but due to the film-forming ability of conventional electrophoretic coatings themselves, such a high thickness cannot be achieved. For example, conventional electrophoretic coatings generally have a film thickness of about 20-30um, and slightly thicker ones are 40-60um, which cannot be applied to these special industries, and powder coatings or spray coatings are still used. Therefore, it is of great significance to study an ultra-thick film type electrophoretic coating to fill the gap in the above situation. Summary of the invention

[0003] The object of the present invention is to provide an ultra-high thickness film type cathode electrophoretic coating to solve one or more of the above-mentioned prior art problems.

[0004] The present invention provides an ultra-high-thickness film type cathode electrophoretic coating, comprising: a color paste and an emulsion;

[0005] The color paste is prepared by grinding a resin with a quaternary ammonium salt or a tertiary amine salt, using heat-expandable microspheres as fillers, adding carbon black, a dispersant, a defoamer, pure water, and lactic acid, and controlling the grinding process temperature.

[0006] The emulsion is a universal emulsion.

[0007] In certain embodiments, the color paste includes the following components in parts by weight:

[0008]

[0009]

[0010] In certain embodiments, the heat-expandable microspheres are iron sulfate powder-modified heat-expandable microspheres.

[0011] In certain embodiments, the preparation method of the heat-expandable microspheres is:

[0012] The iron sulfate powder and the expanded microspheres are mixed, added into a reaction vessel with negative pressure, fully stirred under the negative pressure of less than 10 Pa, and then allowed to settle, and the precipitated expanded microspheres are taken out and air-dried to obtain the heat-expandable microspheres.

[0013] In certain embodiments, the iron sulfate powder accounts for 5-10% by weight of the heat-expandable microspheres.

[0014] Among them: the surface of the expanded microspheres before modification is a layer of thermoplastic polymer shell, which does not have good wear resistance. The expanded microspheres after modification will form a hard mineral shell on the polymer surface, which has strong wear resistance, avoiding the damage of zirconium beads to the thermal expansion microspheres during the grinding process of the color paste, greatly improving the foaming rate of the expanded microspheres, and further improving the thick film stability of the product.

[0015] In certain embodiments, the expanded microspheres are Matsumoto F-230D.

[0016] In certain embodiments, the preparation method of the color paste is:

[0017] Add grinding resin, lactic acid and pure water to a dispersion container, neutralize and disperse at 350-450rpp / min for 20 minutes, then add defoamer and dispersant, disperse at 350-450rpp / min for 10 minutes, add heat-expandable microspheres, continue to disperse at 350-450rpp / min for 10 minutes, then add carbon black and continue to disperse for 10 minutes, transfer the dispersed material to a sand mill, add zirconium beads, grind at 5000rpp / min, and discharge when the fineness of the color paste is ≤20μm to obtain the color paste.

[0018] In certain embodiments, the material temperature is controlled to be ≤ 40°C during the grinding process.

[0019] In certain embodiments, the color paste has a viscosity of 40-80".

[0020] In certain embodiments, the general-purpose emulsion is a polyether-modified epoxy emulsion.

[0021] Among them: the polyether modified epoxy emulsion is achieved by grafting polyether with epoxy through imidazole catalysis, reacting on the main chain, reducing the Tg of the product to achieve better ductility. When used with expanding microsphere color paste, the paint film can have a dense and well-leveled appearance during the expansion and curing process, eliminating the cracking, roughness and other defects caused by poor ductility of the product.

[0022] Beneficial effects: The ultra-high-thickness cathode electrophoretic coating provided by the present invention utilizes the characteristic that the volume of heat-expandable microspheres expands several times or dozens of times after being heated, so that the film thickness of the electrophoretic coating increases significantly during the baking process to achieve the effect of ultra-thick film. Since the thick film effect is brought about by the volume expansion of the heat-expandable microspheres, the use cost will not increase during use due to the increase in the film thickness of the paint film. At the same time, since the expanded microspheres are hollow core-shell structures with good electrical resistance, the product has very excellent throwing power and can be used in various workpiece products with complex inner cavities. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below through embodiments.

[0024] Example 1

[0025] An ultra-high-thickness electrophoretic coating, composed of the following components: the color paste part is made by grinding quaternary ammonium salt or tertiary amine salt resin with heat-expandable microspheres as fillers, adding carbon black, dispersant, defoamer, pure water, lactic acid, and grinding by controlling the grinding process temperature. The grinding process temperature must be strictly controlled to avoid expansion of expandable microspheres due to local overheating during the grinding process; the emulsion part is a polyether-modified epoxy emulsion.

[0026] The specific preparation method of the above color paste is as follows: 200 parts by weight of grinding resin, 15 parts by weight of lactic acid and 350 parts by weight of pure water are added to a dispersion container, and the mixture is neutralized and dispersed at 350-450 rpp / min for 20 minutes, and then 0.5 parts by weight of defoamer and 2 parts by weight of dispersant are added, and the mixture is dispersed at 350-450 rpp / min for 10 minutes, 150 parts by weight of heat-expandable microspheres are added, and the mixture is dispersed at 350-450 rpp / min for 10 minutes, and then 45 parts by weight of carbon black are added and the mixture is dispersed for 10 minutes, and the dispersed material is transferred to a sand mill, zirconium beads are added, and the mixture is ground at 5000 rpp / min, and the material temperature is controlled to be ≤40°C during the grinding process, and the material is discharged when the fineness of the color paste is ≤20 μm, and the viscosity of the color paste is controlled to be 40-80″.

[0027] Wherein: the heat-expandable microspheres are heat-expandable microspheres modified with iron sulfate powder, and the expandable microspheres are Matsumoto F-230D; the preparation method is:

[0028] The iron sulfate powder and the expanded microspheres are mixed, added into a reaction vessel with negative pressure, fully stirred under a negative pressure of less than 10 Pa, and then allowed to settle, and the precipitated expanded microspheres are taken out and air-dried to obtain the heat-expandable microspheres;

[0029] Wherein: the weight percentage of iron sulfate powder in the thermal expansion microspheres is 5-10%.

[0030] Example 2

[0031] An ultra-high-thickness electrophoretic coating, composed of the following components: the color paste part is made by grinding quaternary ammonium salt or tertiary amine salt resin with heat-expandable microspheres as fillers, adding carbon black, dispersant, defoamer, pure water, lactic acid, and grinding by controlling the grinding process temperature. The grinding process temperature must be strictly controlled to avoid expansion of expandable microspheres due to local overheating during the grinding process; the emulsion part is a polyether-modified epoxy emulsion.

[0032] The specific preparation method of the above color paste is as follows: 250 parts by weight of grinding resin, 20 parts by weight of lactic acid and 450 parts by weight of pure water are added to a dispersion container, and the mixture is neutralized and dispersed at 350-450 rpp / min for 20 minutes, and then 1.0 parts by weight of defoamer and 5 parts by weight of dispersant are added, and the mixture is dispersed at 350-450 rpp / min for 10 minutes, 170 parts by weight of heat-expandable microspheres are added, and the mixture is dispersed at 350-450 rpp / min for 10 minutes, and then 60 parts by weight of carbon black are added and dispersed for 10 minutes, and the dispersed material is transferred to a sand mill, zirconium beads are added, and the mixture is ground at 5000 rpp / min, and the material temperature is controlled to be ≤40°C during the grinding process, and the material is discharged when the fineness of the color paste is ≤20 μm, and the viscosity of the color paste is controlled to be 40-80″.

[0033] Wherein: the heat-expandable microspheres are heat-expandable microspheres modified with iron sulfate powder, and the expandable microspheres are Matsumoto F-230D; the preparation method is:

[0034] The iron sulfate powder and the expanded microspheres are mixed, added into a reaction vessel with negative pressure, fully stirred under a negative pressure of less than 10 Pa, and then allowed to settle, and the precipitated expanded microspheres are taken out and air-dried to obtain the heat-expandable microspheres;

[0035] The weight percentage of the iron sulfate powder in the heat-expandable microspheres is 5-10%.

[0036] Example 3

[0037] An ultra-high-thickness electrophoretic coating, composed of the following components: the color paste part is made by grinding quaternary ammonium salt or tertiary amine salt resin with heat-expandable microspheres as fillers, adding carbon black, dispersant, defoamer, pure water, lactic acid, and grinding by controlling the grinding process temperature. The grinding process temperature must be strictly controlled to avoid expansion of expandable microspheres due to local overheating during the grinding process; the emulsion part is a polyether-modified epoxy emulsion.

[0038] The specific preparation method of the above color paste is as follows: 225 parts by weight of grinding resin, 18 parts by weight of lactic acid and 400 parts by weight of pure water are added to a dispersion container, neutralized and dispersed at 350-450rpp / min for 20 minutes, then 0.8 parts by weight of defoamer and 3.5 parts by weight of dispersant are added, dispersed at 350-450rpp / min for 10 minutes, 160 parts by weight of heat-expandable microspheres are added, and dispersed at 350-450rpp / min for 10 minutes, and then 53 parts by weight of carbon black are added and dispersed for 10 minutes. The dispersed material is transferred to a sand mill, zirconium beads are added, and ground at 5000rpp / min. The material temperature is controlled to be ≤40°C during the grinding process. The material is discharged when the fineness of the color paste is ≤20μm, and the viscosity of the color paste is controlled to be 40-80″.

[0039] Wherein: the heat-expandable microspheres are heat-expandable microspheres modified with iron sulfate powder, and the expandable microspheres are Matsumoto F-230D; the preparation method is:

[0040] The iron sulfate powder and the expanded microspheres are mixed, added into a reaction vessel with negative pressure, fully stirred under a negative pressure of less than 10 Pa, and then allowed to settle, and the precipitated expanded microspheres are taken out and air-dried to obtain the heat-expandable microspheres;

[0041] The weight percentage of the iron sulfate powder in the heat-expandable microspheres is 5-10%.

[0042] The emulsion and color paste obtained in Example 1-3 were diluted with water in a ratio of 1:4-6 and stirred evenly to obtain a bath solution capable of normal electrophoresis. The electrophoretic plates were prepared under different conditions with conventional electrophoretic paint, and baked and cooled at 180°C for 20-30 minutes. The appearance of the samples was compared. The comparison of the appearance of the samples is shown in the following table:

[0043]

[0044] It can be seen from the above table that the electrophoretic coating prepared by the present invention has ultra-thick film properties under the same electrophoretic conditions, and also has good properties such as good throwing power.

[0045] In summary: the ultra-high thick film electrophoretic coating provided by the present invention uses the characteristic of thermal expansion of heat-expandable microspheres to act as fillers in the color paste and be ground in the color paste so that after electrophoresis, the thermal expansion microspheres are evenly distributed in the paint film. During the baking curing agent process, when the baking temperature reaches the expansion temperature of the thermal expansion microspheres, the electrophoretic paint film expands and amplifies to achieve the effect of an ultra-thick film. At the same time, because the expandable microspheres are a hollow core-shell structure and have good electrical resistivity, the product has very excellent penetration and can be used in various complex workpieces to make the film thickness inside and outside the workpiece relatively uniform.

[0046] The above description is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the present invention, and these should also be regarded as within the scope of protection of the invention.

Claims

1. An ultra-high thick film type cathodic electrophoretic coating, comprising: Color paste and emulsion; characterized in that, The color paste is prepared by grinding a resin with a quaternary ammonium salt or a tertiary amine salt, using heat-expandable microspheres as fillers, adding carbon black, a dispersant, a defoamer, pure water, and lactic acid, and controlling the grinding process temperature. The emulsion is a universal emulsion.

2. The ultra-high-thickness film type cathodic electrophoretic coating according to claim 1, characterized in that: The color paste includes the following components in parts by weight:

3. The ultra-high thick film type cathodic electrophoretic coating according to claim 2, characterized in that: The heat-expandable microspheres are iron sulfate powder-modified heat-expandable microspheres.

4. The ultra-high thick film type cathodic electrophoretic coating according to claim 3, characterized in that: The preparation method of the heat-expandable microspheres is as follows: The iron sulfate powder and the expanded microspheres are mixed, added into a reaction vessel with negative pressure, fully stirred under the negative pressure of less than 10 Pa, and then allowed to settle, and the precipitated expanded microspheres are taken out and air-dried to obtain the heat-expandable microspheres.

5. The ultra-high thick film type cathodic electrophoretic coating according to claim 4, characterized in that: The expanded microspheres are Matsumoto F-230D.

6. The ultra-high-thickness film type cathodic electrophoretic coating according to claim 1, characterized in that: The preparation method of the color paste is: Add grinding resin, lactic acid and pure water to a dispersion container, neutralize and disperse at 350-450rpp / min for 20 minutes, then add defoamer and dispersant, disperse at 350-450rpp / min for 10 minutes, add heat-expandable microspheres, continue to disperse at 350-450rpp / min for 10 minutes, then add carbon black and continue to disperse for 10 minutes, transfer the dispersed material to a sand mill, add zirconium beads, grind at 5000rpp / min, and discharge when the fineness of the color paste is ≤20μm to obtain the color paste.

7. The ultra-high-thickness film type cathodic electrophoretic coating according to claim 6, characterized in that: During the grinding process, the material temperature is controlled to be ≤40℃.

8. The ultra-high-thickness film type cathodic electrophoretic coating according to claim 6, characterized in that: The viscosity of the color paste is 40-80".

9. The ultra-high-thickness film type cathodic electrophoretic coating according to claim 1, characterized in that: The universal emulsion is a polyether-modified epoxy emulsion.

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