Method for optimizing curing speed of 2K varnish in automobile coating process

Abstract

The invention provides a method for optimizing the curing speed of 2K varnish in the automobile coating process, and the method comprises the following steps: mixing varnish and a curing agent according to a preset proportion to obtain 2K varnish to be detected; coating the 2K varnish to be detected on the substrate, and curing for a preset time at normal temperature to obtain a varnish film with a preset initial area formed by the 2K varnish to be detected on the substrate; cleaning a varnish film with a preset amount of a varnish cleaning solvent at a constant speed; determining the cleaning area of the varnish film cleaned by the varnish cleaning solvent; the ratio of the cleaning area to the initial area is obtained; and based on the preset time and the ratio, the curing speed of the 2K varnish is optimized. According to the method for optimizing the curing speed of the 2K varnish in the automobile coating process, provided by the invention, the curing speed can be optimized by combining the ratio of the cleaning area to the initial area and the preset time in a manner of cleaning the varnish film with the varnish cleaning solvent at a constant speed, and the appropriate curing speed required in the automobile coating process can be obtained.

Description

Technical Field

[0001] The present application relates to the technical field of automobile painting, and in particular to a method for optimizing the curing speed of 2K varnish during automobile painting. Background Art

[0002] 2K varnish is a two-component material, consisting of two components, varnish and curing agent. They are mixed, sprayed and cured in a certain proportion to obtain a varnish film. In the automotive coating production process, the curing speed of the varnish is crucial to the coating quality. If the curing speed is too fast, it is easy to solidify in the spray pipeline after mixing to form varnish residue. If it is too slow, it is easy to cause defects such as sagging and loss of gloss on the car body. Therefore, the curing speed of 2K varnish should be controlled within an appropriate range.

[0003] At present, there is no special testing and evaluation method for the curing speed of 2K varnish in the coating industry. The usual method is to mix the varnish and curing agent and visually observe the state of the cured film. However, when visually observing and evaluating the curing of 2K varnish, individual differences and human subjectivity seriously affect the evaluation results. Therefore, it is difficult to optimize the curing speed of 2K varnish in the automotive coating process based on visual results. Summary of the invention

[0004] To at least partially solve the above problems, an embodiment of the present application provides a method for optimizing the curing speed of 2K varnish in the automobile painting process, comprising: mixing the varnish and the curing agent in a preset ratio to obtain the 2K varnish to be tested; coating the 2K varnish to be tested on a substrate, and curing it at room temperature for a preset time to obtain a varnish film with a preset initial area formed on the substrate by the 2K varnish to be tested; using a preset amount of varnish cleaning solvent to clean the varnish film at a constant speed; determining the cleaned area of ​​the varnish film cleaned by the varnish cleaning solvent; obtaining the ratio of the cleaned area to the initial area; and optimizing the curing speed of the 2K varnish based on the preset time and the ratio.

[0005] In some embodiments, a varnish film is cleaned at a constant speed using a preset amount of varnish cleaning solvent, including: tilting and fixing a substrate relative to a horizontal plane; placing a container containing a preset amount of varnish cleaning solvent above the substrate, controlling the varnish cleaning solvent to drip from the container at a constant speed, and allowing the dripping varnish cleaning solvent to flow through the varnish film on the substrate.

[0006] In some embodiments, the dripping position of the varnish cleaning solvent on the substrate is located on the varnish film and is 1±0.2 cm away from the upper edge of the varnish film.

[0007] In some embodiments, the angle between the substrate and the horizontal plane is 20±5 degrees.

[0008] In some embodiments, the varnish cleaning solvent is controlled to drip onto the substrate from a height of 7±0.5 cm, and the varnish cleaning solvent is controlled to drip out of the container at a constant speed of 1 drop / second.

[0009] In some embodiments, before the 2K varnish to be tested is coated on the substrate, a varnish-specific colorant is added to the 2K varnish to be tested, and the mass ratio of the varnish-specific colorant to the 2K varnish to be tested is 3-5%.

[0010] In some embodiments, a varnish wet film having an initial area and a wet film thickness of 40-50 μm is formed on the substrate by a film applicator.

[0011] In some embodiments, the preset ratio of the volume of the varnish to the curing agent is 100:(30-35).

[0012] In some embodiments, the preset time is 30s, 5min, 10min or 30min.

[0013] In some embodiments, when the preset time is 30s, 5min or 10min: in response to the ratio being less than 35%, the proportion of the curing agent is reduced; in response to the ratio being greater than 70%, the proportion of the curing agent is increased; when the preset time is 30min: in response to the ratio being greater than 35%, the proportion of the curing agent is increased.

[0014] The embodiment of the present application provides a method for optimizing the curing speed of 2K varnish in the automobile painting process. After the 2K varnish to be tested is cured for a preset time to form a varnish film, the varnish film is cleaned at a constant speed by a varnish cleaning solvent. The curing degree of the varnish film is obtained by combining the ratio of the cleaning area to the initial area. Combined with the preset time, the curing speed can be optimized more objectively to obtain the appropriate curing speed required in the automobile painting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 It is a schematic diagram of using a varnish cleaning solvent to clean a varnish film provided in an embodiment of the present application.

[0017] The reference numerals are as follows:

[0018] 1. Burette; 2. Varnish cleaning solvent; 3. Substrate; 4. Waste liquid collection device; 5. Bracket.

[0019] It should be understood that the size of each part shown in the accompanying drawings is not drawn according to the actual proportional relationship. In addition, the same or similar reference numerals represent the same or similar components. DETAILED DESCRIPTION

[0020] The technical scheme of the preferred embodiment of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection claimed in the present application.

[0021] The use of words such as "include" or "comprises" in this application means that the elements before the word include the elements listed after the word, and does not exclude the possibility of including other elements. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] Combination Figure 1, an embodiment of the present application provides a method for optimizing the curing speed of 2K varnish during automobile painting, comprising: mixing varnish and curing agent in a preset ratio to obtain a 2K varnish to be tested; coating the 2K varnish to be tested on a substrate, curing it at room temperature for a preset time, and obtaining a varnish film with a preset initial area formed on the substrate by the 2K varnish to be tested; using a preset amount of varnish cleaning solvent to clean the varnish film at a constant speed; determining the cleaning area of ​​the varnish film cleaned by the varnish cleaning solvent; obtaining the ratio of the cleaning area to the initial area; and optimizing the curing speed of the 2K varnish based on the preset time and the ratio. In this embodiment, the substrate can be made of glass, and after the varnish and curing agent are mixed in a preset ratio, they can be scraped onto the substrate. The 2K varnish to be tested is cured at room temperature, which meets the actual curing conditions of the 2K varnish before the car body is dried, and a more realistic curing speed can be obtained. When 2K varnish is coated on a substrate, a varnish wet film with an initial area can be formed on the substrate by a film applicator. The thickness of the varnish wet film can be 40~50μm. In this way, the initial area and the film thickness can be effectively controlled to control the variables and obtain a more accurate curing speed. When the varnish film is cleaned with a varnish cleaning solvent, the varnish film will be partially dissolved in the varnish cleaning solvent, which is manifested as the disappearance of part of the varnish film, exposing part of the substrate covered by the varnish film. The area of ​​the substrate exposed due to the varnish film being cleaned by the varnish cleaning solvent is the cleaning area. The ratio of the cleaning area to the initial area can reflect the degree of curing of the varnish film within the preset time. Specifically, when the ratio is small, it means that the cleaning area is small, the curing degree of the varnish film is high, and the curing speed is fast. When the ratio is large, it means that the cleaning area is large, the curing degree of the varnish film is low, and the curing speed is slow. Combined with the preset time, the curing speed can be optimized and applied to actual production.

[0023] The embodiment of the present application provides a method for optimizing the curing speed of 2K varnish in the automobile painting process. After the 2K varnish to be tested is cured for a preset time to form a varnish film, the varnish film is cleaned at a constant speed by a varnish cleaning solvent. The curing degree of the varnish film is obtained by combining the ratio of the cleaning area to the initial area. Combined with the preset time, the curing speed can be optimized more objectively to obtain the appropriate curing speed required in the automobile painting process.

[0024] In some embodiments, using a preset amount of varnish cleaning solvent to clean the varnish film at a constant speed includes: tilting and fixing the substrate relative to a horizontal plane; placing a container containing a preset amount of varnish cleaning solvent above the substrate, controlling the varnish cleaning solvent to drip from the container at a constant speed, and allowing the dripped varnish cleaning solvent to flow through the varnish film on the substrate. Figure 1As shown, the substrate 3 can be placed on a bracket 5 with a preset tilt angle, and the bracket 5 can be placed in a waste liquid collection device 4 to facilitate the collection and treatment of waste liquid. For example, the container can be a burette 1, and a scale line is provided on the burette 1 to facilitate the determination of the volume of the varnish cleaning solvent and to achieve control of the preset amount. At the same time, a valve is also provided on the burette 1. By controlling the opening of the valve, the dripping speed of the varnish cleaning solvent 2 can be controlled to achieve a constant speed. By controlling the amount of the varnish cleaning solvent and the dripping speed of the varnish cleaning solvent, the influence of these two factors on the cleaning area can be eliminated as much as possible, so that the measurement result of the curing speed is more accurate.

[0025] In some embodiments, the dripping position of the varnish cleaning solvent on the substrate is located on the varnish film and is 1±0.2 cm, preferably 1 cm, from the upper edge of the varnish film. In this embodiment, by controlling the dripping position, the rinsing effect of the varnish cleaning solvent on the varnish film can be ensured. In this embodiment, the length of the varnish film can be 10 to 20 cm.

[0026] In some embodiments, the angle between the substrate and the horizontal plane is 20±5 degrees, preferably 20 degrees. In this embodiment, by controlling the angle between the substrate and the horizontal plane, the speed at which the varnish cleaning solvent flows through the varnish film can be controlled, thereby ensuring that the varnish cleaning solvent has sufficient contact time with the varnish film.

[0027] In some embodiments, the varnish cleaning solvent is controlled to drip onto the substrate from a height of 7±0.5 cm, and the varnish cleaning solvent is controlled to drip from the container at a constant speed of 1 drop / second. In this embodiment, by controlling the dripping height and dripping speed of the varnish cleaning solvent, splashing of the varnish cleaning solvent can be prevented, and at the same time, appropriate cleaning force can be provided.

[0028] In some embodiments, before the 2K varnish to be tested is coated on the substrate, a varnish-specific colorant is added to the 2K varnish to be tested, and the mass ratio of the varnish-specific colorant to the 2K varnish to be tested is 3-5%. In this embodiment, by adding the varnish-specific colorant to the 2K varnish to be tested, the varnish film can be clearly colored, and the varnish film can be more easily observed, thereby more accurately determining the cleaning area.

[0029] In some embodiments, the preset ratio of the volume of the varnish to the curing agent is 100:(30-35). When the volume of the varnish to the curing agent meets the above preset ratio, a more suitable curing speed can be achieved. The specific ratio can be fine-tuned by adjusting the amount of the curing agent according to the measured curing speed.

[0030] In some embodiments, the preset time is 30s, 5min, 10min or 30min. Among the above times, 30s is the time from the varnish and curing agent are mixed in the spraying equipment to the time they are sprayed onto the car body in the actual production process; 5min and 10min are the common times from the varnish and curing agent are mixed in the spraying equipment to the car body starting to dry; 30min is the limit time from the varnish and curing agent are mixed in the spraying equipment to the car body starting to dry, considering unexpected situations in production (such as equipment shutdown, etc.). The above time points are representative in the actual production of automobile painting.

[0031] In some embodiments, when the preset time is 30s, 5min or 10min: in response to the ratio being less than 35%, the proportion of the curing agent is reduced, and in response to the ratio being greater than 70%, the proportion of the curing agent is increased; when the preset time is 30min: in response to the ratio being greater than 35%, the proportion of the curing agent is increased. When the preset time is other values, such as 20min, in response to the ratio being less than 35%, the proportion of the curing agent can be reduced, and in response to the ratio being greater than 50%, the proportion of the curing agent can be increased.

[0032] The curing speed can be adjusted based on the expected curing degree of the 2K varnish within the preset time during actual production. The ratio can be divided into four intervals: Q1, Q2, Q3, and Q4. For example, the ratio corresponding to the Q1 interval can be 0-35%, the ratio corresponding to the Q2 interval can be 35%-50%, the ratio corresponding to the Q3 interval can be 50%-70%, and the ratio corresponding to the Q4 interval can be 70%-100%. Then, according to the time node where the preset time is located in actual production, the expected curing speed of the 2K varnish at this time node is obtained to guide the optimization of the curing speed.

[0033] In actual application, the paint line of a certain workshop often has the problem of dirty spots on the whole vehicle. The defect status is not differentiated by color or component. The dirty spots account for about 2% of the whole vehicle. Each vehicle needs to be polished if there are more than 30 dirty spots. In response to this problem, the cause investigation and system analysis were carried out. First, the paint residue of the varnish layer was sampled and analyzed under a microscope. It was found that the crystal state of the paint residue was similar to that of the wet film paint residue of the vehicle body. Then, the varnish residue was analyzed by infrared reflection scanning. The results showed that the main component was the cross-linked product of hydroxyl group and isocyanate group (characteristic peak 1529cm -1 and 1690cm -1), analysis showed that the paint residue was formed by the curing reaction of the 2K varnish, and it was discovered that the problem was mainly caused by the crystallization of the varnish layer causing the paint residue. Furthermore, the topcoat site of the workshop adjusted the curing speed of the 2K varnish in the automobile painting process through the method provided in the embodiments of the present application for optimizing the curing speed of the 2K varnish, so that the curing film formation of the varnish film was more in line with the on-site process construction quality, eliminating the problem of paint residue caused by the crystallization of the varnish caused by an inappropriate curing speed, and greatly improving the dirty spot defects of the entire vehicle, greatly alleviating the pressure on various aspects of coating capacity, quality and cost.

[0034] The method for optimizing the curing speed of 2K varnish in the automobile painting process provided in the embodiments of the present application can clearly observe and determine the curing speed of 2K varnish through the curing effect of the varnish film, which is more intuitive and can effectively solve the problem of batch paint residue caused by inappropriate curing speed of 2K varnish, thereby greatly improving the quality of painted car bodies and production efficiency.

[0035] Based on the above-mentioned embodiments of the present application, in the absence of explicit negation or conflict, the technical features of one embodiment may be beneficially combined with one or more other embodiments.

[0036] Although some specific embodiments of the present application have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are only for illustration and not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A method for optimizing the curing speed of 2K clearcoat during automobile painting, characterized in that: include: Mixing the varnish and the curing agent in a preset ratio to obtain a 2K varnish to be tested; The 2K varnish to be tested is coated on a substrate, and cured at room temperature for a preset time to obtain a varnish film having a preset initial area formed by the 2K varnish to be tested on the substrate; Using a preset amount of varnish cleaning solvent to clean the varnish film at a constant speed; Determining the cleaning area of ​​the varnish film cleaned by the varnish cleaning solvent; Obtaining a ratio of the cleaned area to the initial area; Based on the preset time and the ratio, the curing speed of the 2K clearcoat is optimized.

2. The method according to claim 1, characterized in that: Using a preset amount of varnish cleaning solvent to clean the varnish film at a constant speed, comprising: Fixing the substrate tilted relative to a horizontal plane; A container containing a preset amount of varnish cleaning solvent is arranged above the substrate, the varnish cleaning solvent is controlled to drip out of the container at the constant speed, and the dripped varnish cleaning solvent is made to flow through the varnish film on the substrate.

3. The method according to claim 2, characterized in that The dripping position of the varnish cleaning solvent on the substrate is located on the varnish film and is 1±0.2 cm away from the upper edge of the varnish film.

4. The method according to claim 2, characterized in that: The angle between the substrate and the horizontal plane is 20±5 degrees.

5. The method according to claim 2, characterized in that: The varnish cleaning solvent is controlled to drop onto the substrate from a height of 7±0.5 cm, and the varnish cleaning solvent is controlled to drop out from the container at a constant speed of 1 drop / second.

6. The method according to claim 1, characterized in that Before coating the 2K varnish to be tested on the substrate, a special colorant for varnish is added to the 2K varnish to be tested, and the mass ratio of the special colorant for varnish to the 2K varnish to be tested is 3-5%.

7. The method according to claim 1, characterized in that A varnish wet film having the initial area and a wet film thickness of 40 to 50 μm is formed on the substrate by a film applicator.

8. The method according to claim 1, characterized in that The preset ratio of varnish to curing agent volume is 100:(30~35).

9. The method according to claim 8, characterized in that The preset time is 30s, 5min, 10min or 30min.

10. The method according to claim 9, characterized in that When the preset time is 30s, 5min or 10min: in response to the ratio being less than 35%, the proportion of the curing agent is reduced; in response to the ratio being greater than 70%, the proportion of the curing agent is increased; When the preset time is 30 minutes: in response to the ratio being greater than 35%, the proportion of the curing agent is increased.

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