PVD (Physical Vapor Deposition) coating primer with high humidity and heat resistance

Abstract

The invention provides a PVD (Physical Vapor Deposition) coating primer which comprises the following components in parts by weight: 5-30 parts of high-functionality polycarbonate urethane acrylate; 5 to 30 parts of aliphatic polyurethane acrylate; 1 to 20 parts of dipentaerythritol hexaacrylate; 1 to 20 parts of pentaerythritol triacrylate; 5 to 10 parts of a monomer diluent; 1-5 parts of an initiator; 40 to 60 parts of a solvent; and 1-5 parts of an additive. The PVD coating primer disclosed by the invention has good heat and humidity resistance and adhesive force.

Description

Technical Field

[0001] The invention relates to the field of ultraviolet (UV) curing coatings, in particular to UV curing PVD coatings, and more particularly to a PVD coating primer coating. Background Art

[0002] Plastic products are widely used in many fields, such as lamp parts, automotive decorative parts, cosmetic packaging materials, toys and daily commodities. In order to improve the surface decoration of plastic products and present a metallic effect, vacuum coating (PVD) is usually used to form a metal film on the surface of the plastic substrate. However, the vacuum-plated metal film must be equipped with a primer (primer) and a topcoat (topcoat). These two coatings provide different properties and are located on both sides of the metal film layer to improve the adhesion, resistance (such as alcohol resistance, hand sweat resistance, etc.), wear resistance and other physical and chemical properties of the coating. Therefore, coatings play an important role in the application of vacuum coating technology, and their performance will affect the use of plastic products.

[0003] The PVD coating system includes a primer coating and a topcoat coating. Among them, the coating primer coating plays a decisive role in coating shedding in terms of resistance, such as alcohol resistance and moisture and heat resistance. Because there is a void space between the primer and the substrate at the microscopic level, components such as water vapor and alcohol will enter this void space. If the primer is not resistant enough to these substances, it will directly cause the primer to peel off from the substrate surface, and the entire coating structure of the coating will also fall off from the substrate surface, affecting the appearance and use of plastic products.

[0004] In order to improve the performance of PVD coating system, the industry has conducted research and development on coating primer coatings. For example, CN116333581A discloses a high-resistance coating primer coating and its preparation method, which can take into account both adhesion and alcohol resistance. However, this technical solution cannot solve the problem of moisture and heat resistance.

[0005] The main difference between alcohol resistance and heat and humidity resistance lies in temperature. In a heat and humidity environment, the micropores and free volume holes inside the paint film will expand as the temperature rises, and high-concentration water vapor will more easily enter the coating through this channel, thereby destroying the coating structure and corroding the plated metal; while alcohol resistance does not need to consider the impact of high temperature on the paint film, but only needs to consider the coating's resistance to alcohol at room temperature. Therefore, the improvement of heat and humidity resistance requires attention to the heat resistance of the primer.

[0006] In short, the primer coating of PVD coating needs to be resistant to moisture and heat. However, the current primer products of PVD coating cannot meet this demand. Summary of the invention

[0007] In order to solve the above-mentioned deficiencies of the prior art, the present invention provides a highly moisture- and heat-resistant PVD coating primer, which comprises the following components in parts by weight:

[0008]

[0009] The heat-resistant PVD coating primer of the present invention uses high-functionality polycarbonate polyurethane acrylate, which can improve the curing speed and the heat-resistant performance of the primer. At the same time, the present invention proposes the combined use of aliphatic polyurethane acrylate to simultaneously improve the flexibility of the paint film and the bonding strength with the metal coating. Through the synergistic effect of the two resins, the coating primer can have good heat-resistant and moisture-resistant properties and adhesion.

[0010] As mentioned above, the improvement of moisture and heat resistance requires attention to the heat resistance of the primer and how to reduce the expansion of pores and free volume at high temperatures. The present invention mainly improves the heat resistance of the primer by using high-functional polycarbonate polyurethane acrylate.

[0011] Preferably, the PVD coating primer of the present invention comprises the following components in parts by weight:

[0012]

[0013]

[0014] Preferably, the high-functionality polycarbonate urethane acrylate is a decafunctional polycarbonate urethane acrylate.

[0015] Dipentaerythritol hexaacrylate and pentaerythritol triacrylate can increase the curing speed and crosslinking density of the coating, thereby improving the heat resistance and water resistance of the paint film.

[0016] The monomer diluent can be a common diluent, which plays the role of diluting the oligomer, reducing the viscosity of the system, strengthening the erosion of the coating on the surface of the substrate, and improving the bonding force between the coating and the substrate. The monomer diluent is preferably isobornyl methacrylate.

[0017] The photoinitiator may be any commonly used initiator in the industry, preferably benzoin dimethyl ether.

[0018] The additive may include a leveling agent for improving the leveling and wetting effect of the coating. The leveling agent may be a leveling agent commonly used in the art, preferably dimethyl silicone oil.

[0019] The solvent may be a commonly used solvent in the art, and butyl acetate is preferably used.

[0020] Preferably, inorganic nanoparticles (silica) hybrid-modified by surface functional groups can be added to the coating or coating system of the present invention. After the inorganic nanoparticles are hybrid-modified, their dispersibility and compatibility with the resin can be improved. By adding the hybrid-modified inorganic nanoparticles, the hardness and wear resistance can be further enhanced while ensuring transparency.

[0021] Technical effects of the present invention:

[0022] 1. On PC and ABS / PC substrates, the coating primer of the present invention has excellent resistance to damp heat and adhesion to the substrate.

[0023] 2. In addition to providing adhesion to the substrate, the PVD coating primer of the present invention also has excellent interlayer adhesion and can form excellent interlayer adhesion with the metal coating.

[0024] 3. In a high-temperature and high-humidity environment, the PVD coating primer of the present invention can effectively inhibit the corrosion of the metal coating and maintain the metallic luster and beauty of the product for a long time. Specific embodiments

[0025] The following specific examples are used to illustrate the implementation manners of the present invention.

[0026] [Preparation example]

[0027] In the order of feeding resin, monomer, initiator, additive, and solvent, deca-functional polycarbonate polyurethane acrylate, aliphatic polyurethane acrylate, dipentaerythritol hexaacrylate, pentaerythritol triacrylate isobornyl methacrylate, benzoin dimethyl ether, dimethyl silicone oil, and butyl acetate are successively put into a container. Note that a suitable sampling tool should be selected for feeding, and the actual added amount of each weighing should be recorded. After the feeding is completed, the total weight is recorded.

[0028] Seal the sample container and place it in an 80°C water bath for heating for 40 - 60 min. After taking it out, use a disperser to disperse the material mixture in the container to make it uniform. It is recommended that the stirring speed be 50 - 300 revolutions / min. After uniform dispersion, make up the solvent according to the total weight and disperse moderately to prepare the coating primer.

[0029] Table 1. Composition of the coating primer according to Examples 1 - 5 of the present invention (by weight parts)

[0030] Example 1 Example 2 Example 3 Example 4 Example 5 Deca-functional polycarbonate polyurethane acrylate 5 30 15 15 15 Aliphatic polyurethane acrylate 5 5 30 10 10 Dipentaerythritol hexaacrylate 1 20 10 10 10 Pentaerythritol triacrylate 20 1 8 8 8 Isobornyl methacrylate 5 10 5 5 5 Benzoin dimethyl ether 3 3 3 3 5 Dimethyl silicone oil 1 1 1 1 1 Butyl acetate 50 50 50 50 50

[0031] Table 2. Composition of the coating primer according to Comparative Examples 1 - 4 (by weight parts)

[0032] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Deca-functional polycarbonate polyurethane acrylate --- 15 15 15 Aliphatic polyurethane acrylate 10 --- 10 10 Dipentaerythritol hexaacrylate 10 10 --- 10 Pentaerythritol triacrylate 8 10 8 --- Isobornyl methacrylate 5 5 5 5 Benzoin dimethyl ether 3 3 3 3 Dimethyl silicone oil 1 1 1 1 Butyl acetate 50 50 50 50

[0033] [Test example]

[0034] Prepare test samples using the coating primers prepared in the examples and comparative examples, and then conduct tests on the properties after coating curing. The preparation method of the test samples is as follows:

[0035] First, wipe the PC substrate to remove dust, spray the PVD coating primer prepared in the preparation example onto the PC substrate, with the primer film thickness being 20 - 40 μm, bake in an oven at 50 - 70 °C for 4 - 8 min, and then use a light curing machine equipped with a mercury lamp for curing, with the curing energy in the range of 600 - 1200 mj / cm 2 interval range.

[0036] After the primer is cured, place the substrate in a vacuum coating machine for aluminizing. After aluminizing, spray the topcoat. After the topcoat is baked and cured, the PVD coating test sample is obtained.

[0037] Conduct tests on this test sample, including adhesion tests and resistance tests to boiling water, high temperature and high humidity, condensed water, etc.

[0038] [Test methods]

[0039] 1. Adhesion

[0040] The adhesion test uses the cross - cut method, 3M600 tape, ISO grade 1 and ASTM 4B standards. There are small pieces of peeling along the scribe edges or at the intersections of the knife marks of the paint layer, and it is required that the actual damage within the scribe area ≤ 5%.

[0041] 2. Resistance to boiling water performance

[0042] Put the test sample into boiling water at 100 °C for boiling, and test how long it takes for the performance to change (such as blistering, peeling, adhesion test NG, etc.). This test performance can be used to evaluate the durability of the coating to high - temperature liquid water and the thermal stability of the primer.

[0043] 3. Resistance to high temperature and high humidity performance

[0044] Put the test sample into a high - temperature and high - humidity chamber at 90 °C and 96% RH, and test how long it takes for the performance to change (such as blistering, coating corrosion, adhesion test NG, etc.). This test performance can be used to evaluate the durability of the coating to high - temperature water vapor and the ability of the coating to inhibit the entry of high - temperature water vapor to corrode the metal coating.

[0045] 4. Resistance to condensed water performance

[0046] Place the test sample in an environment of 40°C and 100% water vapor, and test how long it takes for the performance to change (such as blistering, coating corrosion, adhesion test NG, etc.). This test performance can be used to evaluate the resistance of the coating to low-temperature saturated water vapor and the bonding strength between the primer and the coating metal.

[0047] Table 3. Post-curing performance of the PVD coating primer prepared according to the embodiments of the present invention

[0048]

[0049]

[0050] Table 4. Post-curing performance of the PVD coating primer prepared according to the comparative examples

[0051]

[0052] From the test results in Table 3, it can be seen that the PVD coating primer prepared in the embodiments of the present invention has excellent hygrothermal resistance and substrate adhesion. At the same time, it has excellent interlayer adhesion on the basis of the PVD process. It can pass the hygrothermal test (90°C, 96% RH) for 160 h, the condensed water test (40°C, 100% RH) for 160 h, and the 100°C boiling water test for 8 h.

[0053] In contrast, from the performance test results of the comparative example PVD coating primer in Table 4, it can be seen that the performance of the PVD coating primer prepared in the comparative example is significantly reduced.

[0054] In Comparative Example 1, high-functional polycarbonate polyurethane acrylate was not added. Compared with Example 4 of the present invention (the addition amounts of other components in the two formulations are basically the same), the performance of Comparative Example 1 decreased significantly: for the hygrothermal resistance, it was 48 hours in Comparative Example 1 and 160 hours in Example 4 of the present invention; for the condensed water test, it was 48 h in Comparative Example 1 and 160 h in Example 4 of the present invention; for the 100°C boiling water test, it was 2 hours in Comparative Example 1 and 8 hours in Example 4 of the present invention.

[0055] In Comparative Example 2, aliphatic polyurethane acrylate was not added. Compared with Example 4 of the present invention (the addition amounts of other components in the two formulations are basically the same), the performance of Comparative Example 2 decreased significantly: for the adhesion, it was grade 3 in Comparative Example 2 and grade 0 in Example 4 of the present invention.

[0056] In Comparative Example 3 and Comparative Example 4, dipentaerythritol hexaacrylate and pentaerythritol triacrylate were not added. Compared with Example 4 of the present invention (the addition amounts of other components in the two formulations were basically the same), the performance decreased significantly: for the damp heat resistance performance, it was 96 hours for Comparative Example 3 and 72 hours for Comparative Example 4, while it was 160 hours for Example 4 of the present invention; for the condensed water test, it was 120 hours for Comparative Example 3 and 96 hours for Comparative Example 4, while it was 160 h for Example 4 of the present invention; for boiling in water at 100 °C, it was 2 hours for Comparative Example 3 and 1 hour for Comparative Example 4, while it was 8 hours for Example 4 of the present invention.

[0057] Although embodiments of the present invention have been described herein, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalent substitutions.

Claims

1. A PVD coating primer, by weight parts, comprises the following components:

2. The PVD coating primer according to claim 1, by weight parts, comprises the following components:

3. The PVD coating primer according to claim 1, wherein, The high-functional polycarbonate polyurethane acrylate is deca-functional polycarbonate polyurethane acrylate.

4. The PVD coating primer according to claim 1, wherein, The monomer diluent is isobornyl methacrylate.

5. The PVD coating primer according to claim 1, wherein, The photoinitiator is benzoin dimethyl ether.

Images