A thermosetting vacuum electroplating primer and its application

Abstract

This invention belongs to the field of vacuum electroplating primer technology, and relates to a thermosetting vacuum electroplating primer and its application. The thermosetting vacuum electroplating primer is processed from raw materials comprising the following parts by weight: 10-40 parts of low-hydroxyl-value acrylic resin, 10-30 parts of high-hydroxyl-value acrylic resin, 0.1-1 parts of leveling agent, 20-60 parts of thinner, and 0-20 parts of curing agent. The thermosetting vacuum electroplating primer provided by this invention, through the combined use of multiple components and optimized raw material ratios, forms a primer spraying process that can be cured by low-temperature baking. This effectively solves the problem of uneven curing of UV-cured coatings on large areas and complex structures, thus enabling the successful extension of vacuum electroplating technology to the surface treatment of large or complex products, and is also applicable to plastic products with low temperature resistance.

Description

Technical Field

[0001] This invention belongs to the field of vacuum electroplating primer technology, and relates to a thermosetting vacuum electroplating primer and its application. Background Technology

[0002] Vacuum electroplating, a precise and advanced surface treatment process, relies on creating a high-vacuum environment to ensure that the evaporated metal is directly and purely deposited onto the plastic substrate without the need for liquid electrolytes. This avoids the environmental pollution and chemical corrosion problems that can occur in traditional wet electroplating. This process not only gives plastic products a luxurious metallic appearance, enhancing their aesthetic value and market competitiveness, but also cleverly preserves or enhances the product's light transmittance and electromagnetic wave penetration capabilities. This is particularly important for manufacturing functional automotive parts, such as headlight covers and antenna covers.

[0003] Facing the dual challenges of modern industry's demands for product performance and environmental standards, vacuum electroplating technology stands out with its unique advantages. It is not limited to metallic coatings but can also precisely control the deposition of non-metallic thin films, such as oxides and nitrides, providing a multifunctional, high-performance surface protection solution for automotive parts. These films are not only aesthetically pleasing but also possess excellent physical properties, such as high strength, high wear resistance, and outstanding corrosion resistance, significantly extending product lifespan and reliability.

[0004] It is worth noting that when vacuum electroplating is combined with modern coating technology, it tends to use a UV-cured primer as a pretreatment step. However, when applying UV curing to large or structurally complex automotive parts, uneven curing may occur. This is because light cannot evenly radiate to all sprayed areas, affecting the stability and durability of the final coating. Furthermore, to meet the curing requirements of special parts, companies may need to configure customized light source systems or large curing equipment, which undoubtedly increases process costs. Summary of the Invention

[0005] This invention addresses the problems existing in the vacuum electroplating primer in the prior art by providing a thermosetting vacuum electroplating primer and its application.

[0006] One objective of this invention is achieved through the following technical solution:

[0007] A thermosetting vacuum electroplating primer, wherein the thermosetting vacuum electroplating primer is processed from raw materials comprising the following parts by weight: 10-40 parts of low hydroxyl value acrylic resin, 10-30 parts of high hydroxyl value acrylic resin, 0.1-1 parts of leveling agent, 20-60 parts of diluent, and 0-20 parts of curing agent.

[0008] Preferably, the thermosetting vacuum electroplating primer is made from the following raw materials in parts by weight: 10-30 parts of low hydroxyl value acrylic resin, 10-20 parts of high hydroxyl value acrylic resin, 0.1-1 parts of leveling agent, 30-50 parts of diluent, and 1-15 parts of curing agent.

[0009] Preferably, the hydroxyl content in the low hydroxyl value acrylic resin is 0.5wt% ≤ 2wt%, and can be listed as 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1.0wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, 2.0wt%, etc.

[0010] Preferably, the hydroxyl content in the high hydroxyl value acrylic resin is 2wt% < hydroxyl content ≤ 4wt%, and can be listed as 2.1wt%, 2.2wt%, 2.3wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.7wt%, 2.8wt%, 2.9wt%, 3.0wt%, 3.1wt%, 3.2wt%, 3.3wt%, 3.4wt%, 3.5wt%, 3.6wt%, 3.7wt%, 3.8wt%, 3.9wt%, 4.0wt%, etc.

[0011] Preferably, the low hydroxyl value acrylic resin includes one or more of Dongsheng Chemical ESB-1252DS, Keding Technology MR1438, and Jianxing Chemical AA-5117. The low hydroxyl value acrylic resin used in this invention has excellent adhesion to polycarbonate (PC) substrates.

[0012] Preferably, the high hydroxyl value acrylic resin includes one or more of the following: Dongsheng Chemical ESB-12AD11, Yake Chemical YZ-H728, Jianxing Chemical AA-5330, and Keding Materials MR14898. The high hydroxyl value acrylic resin used in this invention exhibits excellent surface properties after curing.

[0013] Preferably, the leveling agent is an acrylate leveling agent.

[0014] More preferably, the leveling agent includes one or more of BYK-392, BYK-358N, and tego2100.

[0015] Preferably, the diluent includes one or more of ethyl acetate, butyl acetate, toluene, xylene, propylene glycol methyl ether, propylene glycol methyl ether acetate, isopropanol, n-butanol, ethanol, diacetone alcohol, butanone, methyl isobutyl ketone, and ethylene glycol monobutyl ether.

[0016] Preferably, the curing agent is an isocyanate curing agent.

[0017] More preferably, the curing agent includes one or more of Desmodur N3390, Desmodur N3800, and HT-100.

[0018] Preferably, the amount of curing agent is calculated based on the amount of hydroxyl acrylic resin used, the hydroxyl (-OH) content of the resin, and the isocyanate group (-NCO) content of the curing agent. The specific calculation method is as follows:

[0019] Curing agent dosage = 2.47 × [(resin dosage × resin solid content % × OH%) / NCO%];

[0020] Wherein, OH% represents the percentage content of hydroxyl groups when the resin used is 100% solid resin; NCO% represents the percentage content of NCO groups in the curing agent used; 2.47 is an empirical constant, based on the theoretical stoichiometric relationship between -NCO and -OH being 1:1 (i.e., each -NCO group can theoretically react with one -OH group).

[0021] Another objective of this invention is achieved through the following technical solution:

[0022] A spraying process for a thermosetting vacuum electroplating primer, the spraying process comprising the following steps:

[0023] The raw materials of the above-mentioned thermosetting vacuum electroplating primer are mixed and dispersed evenly, sprayed onto the vacuum electroplating substrate, and then thermosetting.

[0024] Preferably, the thickness of the vacuum electroplating primer coating is 20–30 μm.

[0025] Preferably, the thermosetting temperature is 60–85°C and the time is 30–60 min.

[0026] Preferably, the raw material of the thermosetting vacuum electroplating primer is a two-component coating, including a curing agent component and other raw material components, with the curing agent component added before spraying.

[0027] Another objective of this invention is achieved through the following technical solution:

[0028] A vacuum electroplating coating process includes spraying the above-mentioned thermosetting vacuum electroplating primer, PVD metallization, and topcoat spraying.

[0029] Preferably, the PVD metallized film includes an indium-plated film or an aluminum-plated film.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. This invention provides a thermosetting vacuum electroplating primer, which, through the combined use of multiple components and optimized raw material ratios, forms a primer spraying process that can be cured by low-temperature baking. The combination of multiple components not only ensures excellent adhesion to polycarbonate (PC) substrates but also provides good bonding between the primer and the metal plating layer.

[0032] 2. The thermosetting vacuum electroplating primer provided by this invention utilizes preferred low-hydroxyl-value acrylic resins (Dongsheng Chemical ESB-1252DS, Keding Chemical MR1438, and Jianxing Chemical AA-5117) to ensure excellent adhesion to materials such as polycarbonate (PC). High-hydroxyl-value acrylic resins (Dongsheng Chemical ESB-12AD11, Yake Chemical YZ-H728, Jianxing Chemical AA-5330, and Keding Chemical MR14898), after heat treatment, impart excellent appearance and texture to vacuum electroplated products, significantly improving the surface effect of the vacuum electroplated layer. The preferred raw material scheme not only provides good adhesion, moisture resistance, and heat resistance, but also ensures that the metal coating maintains high gloss and adhesion after coating the paint film surface.

[0033] 3. The thermosetting vacuum electroplating primer provided by this invention is applied to the spraying process of vacuum electroplating coatings. It is cured by low-temperature baking, which effectively solves the problem that UV-cured coatings are difficult to cure evenly on large and complex parts. This allows vacuum electroplating technology to be successfully extended to the surface treatment of large or complex products, and it is also applicable to plastic products with low temperature resistance. Detailed Implementation

[0034] The technical solution of the present invention will be further described below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various modifications or alterations to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0035] Example 1

[0036] Example 1: The thermosetting vacuum electroplating primer is made from the following raw materials in parts by weight: 20 parts Dongsheng Chemical ESB-1252DS, 10 parts Jianxing Chemical AA-5330, 0.1 parts BYK-392, 25 parts ethyl acetate, 25 parts butyl acetate, and 3 parts Desmodur N3390.

[0037] The vacuum electroplating paint film spraying process of this embodiment includes the following steps: weighing thermosetting vacuum electroplating primer raw materials, mixing and dispersing them evenly, spraying them onto a PC test board with a film thickness of 25μm, curing at 80℃ for 60min, and then performing PVD indium plating and topcoat spraying on the PC board with the cured primer to obtain the vacuum electroplating paint film.

[0038] Example 2

[0039] Example 2: The thermosetting vacuum electroplating primer is made from the following raw materials in parts by weight: 15 parts of Keding Gongcai MR1438, 15 parts of Keding Gongcai MR14898, 0.1 parts of BYK-358N, 25 parts of ethyl acetate, 25 parts of butyl acetate, and 12.6 parts of Desmodur N3800.

[0040] The spraying process of the vacuum electroplated paint film in this embodiment is the same as that in Embodiment 1.

[0041] Example 3

[0042] Example 3: The thermosetting vacuum electroplating primer is made from the following raw materials in parts by weight: 20 parts of Kedinggongcai MR1438, 10 parts of Kedinggongcai MR14898, 0.1 parts of Tego2100, 25 parts of ethyl acetate, 25 parts of butyl acetate, and 10 parts of Desmodur N3800.

[0043] The spraying process of the vacuum electroplated paint film in this embodiment is the same as that in Embodiment 1.

[0044] Example 4

[0045] Example 4: The thermosetting vacuum electroplating primer is made from the following raw materials in parts by weight: 20 parts of Kedinggongcai MR1438, 10 parts of Kedinggongcai MR14898, 0.1 parts of BYK-392, 25 parts of ethyl acetate, 25 parts of butyl acetate, and 5.4 parts of Desmodur N3390.

[0046] The spraying process of the vacuum electroplated paint film in this embodiment is the same as that in Embodiment 1.

[0047] Comparative Example 1

[0048] Comparative Example 1: Vacuum electroplating primer was made from the following raw materials in parts by weight: 30 parts Dongsheng Chemical ESB-1252DS, 0.1 parts BYK-392, 25 parts ethyl acetate, 25 parts butyl acetate, and 1.1 parts Desmodur N3390.

[0049] The spraying process of the vacuum electroplated paint film in this embodiment is the same as that in Embodiment 1.

[0050] Comparative Example 2

[0051] Comparative Example 2: Vacuum electroplating primer was made from the following raw materials in parts by weight: 30 parts Jianxing Chemical AA-5330, 0.1 parts BYK-392, 25 parts ethyl acetate, 25 parts butyl acetate, and 6.7 parts Desmodur N3390.

[0052] The spraying process of the vacuum electroplated paint film in this embodiment is the same as that in Embodiment 1.

[0053] Comparative Example 3

[0054] Comparative Example 3: Vacuum electroplating primer was made from the following raw materials in parts by weight: 25 parts Dongsheng Chemical ESB-1252DS, 5 parts Jianxing Chemical AA-5330, 0.1 parts BYK-392, 25 parts ethyl acetate, 25 parts butyl acetate, and 2.2 parts Desmodur N3390.

[0055] The spraying process of the vacuum electroplated paint film in this embodiment is the same as that in Embodiment 1.

[0056] Comparative Example 4

[0057] Comparative Example 4: Vacuum electroplating primer was made from the following raw materials in parts by weight: 5 parts Dongsheng Chemical ESB-1252DS, 25 parts Jianxing Chemical AA-5330, 0.1 parts BYK-392, 25 parts ethyl acetate, 25 parts butyl acetate, and 5.6 parts Desmodur N3390.

[0058] The spraying process of the vacuum electroplated paint film in this embodiment is the same as that in Embodiment 1.

[0059] Comparative Example 5

[0060] Comparative Example 5: Vacuum electroplating primer was made from the following raw materials in parts by weight: 20 parts Deqian FS-2060A, 10 parts Jianxing Chemical AA-5330, 0.1 parts BYK-392, 25 parts ethyl acetate, 25 parts butyl acetate, and 5 parts Desmodur N3390.

[0061] The spraying process of the vacuum electroplated paint film in this embodiment is the same as that in Embodiment 1.

[0062] Comparative Example 6

[0063] Comparative Example 6: Vacuum electroplating primer was prepared from the following raw materials in parts by weight: 20 parts Dongsheng Chemical ESB-1252DS, 10 parts Cytec SM515, 0.1 parts BYK-392, 25 parts ethyl acetate, 25 parts butyl acetate, and 4 parts Desmodur N3390.

[0064] The spraying process of the vacuum electroplated paint film in this embodiment is the same as that in Embodiment 1.

[0065] Comparative Example 7

[0066] The only difference between Comparative Example 7 and Example 1 is the spraying process of the vacuum electroplating primer.

[0067] The spraying process of the vacuum electroplated paint film in this comparative example includes the following steps: weigh the vacuum electroplating primer raw materials, mix and disperse them evenly, spray them on the PC test board with a film thickness of 25μm, cure them at 90℃ for 5h, and then perform PVD indium plating and topcoat spraying on the PC board with the primer cured to obtain the vacuum electroplated paint film.

[0068] The raw materials for the vacuum electroplating primer in this comparative example are the same as those in Example 1.

[0069] The samples of Examples 1-4 and Comparative Examples 1-7 that were coated with vacuum electroplated paint films were tested for appearance, adhesion, water resistance, water resistance, moisture resistance and thermal aging performance. The specific performance test results are shown in Table 1.

[0070] Table 1. Performance test results for each embodiment and comparative example.

[0071]

[0072]

[0073] As shown in Table 1, it can be seen from Examples 1 to 4 that the vacuum electroplating products obtained by using the thermosetting vacuum electroplating primer of the present invention and the spraying process within the scope of the technical solution not only have good adhesion, moisture resistance and heat resistance, but also can maintain the high gloss and adhesion of the metal coating on the paint film surface.

[0074] As can be seen from Comparative Examples 1 to 4, PVD coatings prepared using primers containing only low-hydroxyl-value acrylic resin are prone to defects such as fogging and orange peel; PVD coatings prepared using primers containing only high-hydroxyl-value acrylic resin will produce performance defects such as poor adhesion; and PVD coatings prepared using primers with raw material ratios of thermosetting vacuum electroplating primers not within the scope of the present invention will exhibit various appearance defects or performance defects.

[0075] As can be seen from Comparative Examples 5 and 6, vacuum electroplating paint films sprayed without using the thermosetting vacuum electroplating primer raw material combination within the scope of the present invention exhibit poor adhesion, despite not having obvious orange peel appearance.

[0076] As can be seen from Comparative Example 7, the vacuum electroplating coating obtained without using the spraying process within the scope of the present invention has poor adhesion performance.

[0077] All aspects, embodiments, and features of this invention should be considered illustrative in all respects and not limiting of the invention; the scope of the invention is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0078] In the preparation method of this invention, the order of the steps is not limited to the listed order. For those skilled in the art, variations in the order of the steps without creative effort are also within the scope of protection of this invention. Furthermore, two or more steps or actions can be performed simultaneously.

[0079] Finally, it should be noted that the specific embodiments described herein are merely illustrative examples of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A vacuum electroplating paint film spraying process, characterized in that, The spraying process includes: spraying of thermosetting vacuum electroplating primer, PVD metallization, and topcoat spraying; The spraying of thermosetting vacuum electroplating primer includes the following steps: mixing and dispersing the raw materials of thermosetting vacuum electroplating primer evenly, spraying it onto the vacuum electroplating substrate and performing thermosetting, wherein the thermosetting temperature is 60~85℃ and the time is 30~60min. The raw materials of the thermosetting vacuum electroplating primer include: 10-40 parts of low hydroxyl value acrylic resin, 10-30 parts of high hydroxyl value acrylic resin, 0.1-1 parts of leveling agent, 20-60 parts of diluent, and 0-20 parts of curing agent. The low hydroxyl value acrylic resin has a hydroxyl content of 0.5wt% ≤ 2wt%, and is selected from one or more of Dongsheng Chemical ESB-1252DS, Keding Chemical MR1438, and Jianxing Chemical AA-5117; the high hydroxyl value acrylic resin has a hydroxyl content of 2wt% < 4wt%, and is selected from one or more of Dongsheng Chemical ESB-12AD11, Yake Chemical YZ-H728, Jianxing Chemical AA-5330, and Keding Chemical MR14898; the curing agent includes one or more of Desmodur N3390, Desmodur N3800, and HT-100.

2. The spraying process according to claim 1, characterized in that, The raw materials of the thermosetting vacuum electroplating primer include: 10-30 parts of low hydroxyl value acrylic resin, 10-20 parts of high hydroxyl value acrylic resin, 0.1-1 parts of leveling agent, 30-50 parts of diluent, and 1-15 parts of curing agent.

3. The spraying process according to claim 1, characterized in that, The leveling agent includes one or more of BYK-392, BYK-358N, and tego2100.

4. The spraying process according to claim 1, characterized in that, The diluent includes one or more of ethyl acetate, butyl acetate, toluene, xylene, propylene glycol methyl ether, propylene glycol methyl ether acetate, isopropanol, n-butanol, ethanol, diacetone alcohol, butanone, methyl isobutyl ketone, and ethylene glycol monobutyl ether.

5. The spraying process according to claim 1, characterized in that, The amount of curing agent is calculated based on the amount of hydroxyl acrylic resin used, the hydroxyl content of the resin used, and the isocyanate group content of the curing agent used.

6. The spraying process according to claim 1, characterized in that, The thickness of the vacuum electroplating primer sprayed is 20~30μm.

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