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CN-121995041-A - Method for rapidly evaluating appearance of electrophoretic coating

CN121995041ACN 121995041 ACN121995041 ACN 121995041ACN-121995041-A

Abstract

The invention relates to a method for rapidly evaluating the appearance of an electrophoretic coating, which is used for measuring the appearance of the electrophoretic coating by dip-coating varnish on the surface of the electrophoretic coating to be measured. The method controls the thickness of the varnish layer which is coated on the electrophoresis layer in a dip-coating way by adjusting the viscosity of the varnish and controlling the vertical leveling time so as to achieve the effect of measuring the appearance. Compared with the traditional spraying process, the method provided by the invention is simpler, the cost is saved, the conditions of serious orange peel of the plate surface, adverse to data measurement and the like caused by the fact that the film thickness of the coating is reduced during spraying are avoided, meanwhile, the single coating has less interference factors compared with the composite coating, and the data accuracy is higher.

Inventors

  • CHEN SHENGPING
  • LU XINYI
  • YI JUNYI
  • Zhang Qingtu
  • LUO JINWEI

Assignees

  • 广州立邦涂料有限公司

Dates

Publication Date
20260508
Application Date
20241101

Claims (10)

  1. 1. A method for rapidly evaluating the appearance of an electrophoretic coating, wherein the appearance of the electrophoretic coating is measured by dip-coating a varnish on the surface of the electrophoretic coating to be measured, comprising the steps of: The method comprises the following steps of S1, preprocessing, construction environment preprocessing and paint preparation, wherein the preprocessing comprises, but is not limited to, preprocessing a plate with an electrophoretic coating to be detected; S2, a coating step, wherein the coating step comprises, but is not limited to, dip-coating, namely dip-coating varnish on the surface of the electrophoretic coating to be detected after pretreatment in the step S1, and the dip-coating time is preferably 20-22S; And S3, judging, namely, measuring the appearance of the varnish layer by using a orange peel instrument, wherein the appearance of the electrophoretic coating is worse as the short wave value measured by the orange peel instrument is larger.
  2. 2. The method for rapid evaluation of appearance of an electrophoretic coating according to claim 1, wherein the pretreatment of the sheet having an electrophoretic coating to be measured comprises wiping the surface and edges of the sheet with an alcohol solution, the pretreatment of the construction environment comprises treating the construction environment to a dust-free environment, the preparation of the coating comprises sampling a varnish in a standard manner and diluting the varnish with an oily solvent to reduce the viscosity of the varnish, and preferably, filtering the varnish with a clean filter cloth before diluting the varnish with the oily solvent in the preparation of the coating.
  3. 3. The method for rapidly evaluating the appearance of an electrophoretic coating according to claim 2, wherein the alcohol solution is ethanol or isopropanol, the pretreatment of the plate material with the electrophoretic coating to be tested is preferably to wipe the plate surface edge of the plate material in one way a plurality of times by using dust-free paper immersed in the alcohol solution, and then wipe the plate surface of the plate material in one way a plurality of times, and the construction environment temperature is 20-24 ℃, preferably 21-23 ℃.
  4. 4. The method for rapid evaluation of the appearance of an electrophoretic coating according to claim 2, wherein the diluted varnish viscosity is preferably 8-12s, more preferably 10s.
  5. 5. The method for rapidly evaluating the appearance of an electrophoretic coating according to claim 2, wherein the oily solvent is ethyl acetate or butyl acetate.
  6. 6. The method for rapidly evaluating the appearance of an electrophoretic coating according to any one of claims 1 to 5, wherein the coating step further comprises a vertical leveling step for controlling the thickness of the coating film after dip-coating the varnish.
  7. 7. The method for rapidly evaluating the appearance of an electrophoretic coating according to claim 6, wherein the vertical leveling time is controlled to be 0 to 60 seconds, and the thickness of the coating film is preferably 2 to 5 μm.
  8. 8. The method for rapidly evaluating the appearance of an electrophoretic coating according to any one of claims 1 to 5, wherein in the coating step, a dip coating method is used to dip coat a varnish on the surface of the electrophoretic coating to be measured, and then a baking step is performed, wherein the baking environment is a dust-free environment.
  9. 9. The method for rapidly evaluating the appearance of an electrophoretic coating according to claim 8, wherein in the baking step, the plate is placed at a horizontal angle, the baking temperature is 130-145 ℃, and the baking time is 15-20min.
  10. 10. The method for rapidly evaluating the appearance of an electrophoretic coating according to any one of claims 1 to 5, wherein the coating step further comprises a vertical leveling step for controlling the thickness of the coating film after the dip-coating varnish and a baking step for controlling the vertical leveling time to 0 to 60s, preferably 2 to 5 μm, wherein the plate is placed at a horizontal angle, the baking temperature is 130 to 145 ℃ and the baking time is 15 to 20min.

Description

Method for rapidly evaluating appearance of electrophoretic coating Technical Field The invention relates to the technical field of automobile coatings, in particular to a method for rapidly evaluating the appearance of an electrophoretic coating. Background Along with the continuous expansion of the automobile market, the coating requirements of passenger cars are also continuously improved, so that the automobile coating has high corrosion resistance and meets the high decorative requirements. For example, the common car coating is required to have the characteristics of no perforating corrosion, high gloss, vividness, and the like for more than 10 years. In the prior art, the electrophoretic coating plays a key role in improving the corrosion resistance, but the surface quality of the electrophoretic coating film also has influence on the appearance quality of the intermediate coating and the finish paint because the coating film is usually formed by compounding multiple coatings. Compared with the quality evaluation of the finish paint, the surface quality evaluation of the electrophoretic paint film is relatively lack of indexes and control means, is not paid enough attention to and process monitoring at present, and the problem of short-wave orange peel of the finish paint of the whole vehicle caused by poor quality of the electrophoretic surface is frequently caused in production, so that a quantitative evaluation method is required to be introduced, and the quality of the electrophoretic paint film is objectively and quantitatively represented. At present, roughness and orange peel are generally adopted as electrophoretic paint film quality evaluation indexes, but a large number of experiments prove that the roughness is not necessarily positively related to the appearance of the whole automobile, but is occasional. The appearance of the whole car may be deteriorated when the roughness is low, and the appearance of the whole car may be improved when the roughness is high. It is difficult to reflect the appearance of the whole coating by roughness alone. Meanwhile, the single electrophoretic coating has low gloss, so that the electrophoretic appearance cannot be well measured by using a orange peel instrument, and the conventional evaluation of the electrophoretic appearance requires the painting of paint varnish in the process of spraying the electrophoretic layer and then the orange peel instrument is used for evaluation. The method needs to consume a large amount of time and paint, and has the defects of excessive interference factors in the spraying process and influence the authenticity of data. In view of the foregoing, there is a need in the art to develop a method for rapidly evaluating the appearance of an electrophoretic coating to solve the problems of the prior art. Disclosure of Invention Based on the above facts, an object of the present invention is to provide a method for rapidly evaluating the appearance of an electrophoretic coating, which measures the appearance of the electrophoretic coating by dip-coating a varnish on the surface of the electrophoretic coating to be measured, and controls the thickness of a dip-coated varnish layer on the electrophoretic layer by adjusting the viscosity of the varnish and controlling the vertical leveling time, so as to achieve the effect of measuring the appearance. The method is simple, convenient and quick to operate, and can save cost while having high data accuracy. In a first aspect the present invention provides a method for rapidly evaluating the appearance of an electrophoretic coating comprising the steps of: s1, a pretreatment step; S2, a coating step; s3, judging. In some embodiments of the present invention, the pretreatment steps include, but are not limited to, pretreatment of the sheet material with the electrocoat to be tested, pretreatment of the construction environment, preparation of the paint, preferably the pretreatment of the sheet material with the electrocoat to be tested includes wiping the surface and edges of the sheet material with an alcohol solution, more preferably the pretreatment of the sheet material with the electrocoat to be tested includes wiping the edges of the sheet material in one direction with a dust-free paper immersed in the alcohol solution, and then wiping the sheet material in one direction multiple times, the pretreatment of the construction environment includes treating the construction environment to a dust-free environment, the preparation of the paint includes taking a sample of the varnish in the GB/T3186-2006 standard method, and diluting the varnish with an oily solvent to reduce the viscosity of the varnish, and more preferably, filtering the varnish with a filter cloth before diluting the varnish with the oily solvent in the preparation of the paint. In some preferred embodiments of the invention, the alcoholic solution is ethanol or isopropanol. In some preferred embodiments of the inve