Anti-burst electroplating primer and preparation method thereof

Abstract

The invention relates to the technical field of electroplating primers, and particularly discloses an anti-burst electroplating primer and a preparation method thereof. The invention relates to an anti-burst electroplating primer which comprises the following components in parts by weight: 8-12 parts of bifunctional polyurethane acrylate; 20 to 25 parts of trifunctional polyester acrylate; 10 to 15 parts of modified epoxy acrylic resin; 13 to 20 parts of a UV monomer; 4-6 parts of a photoinitiator; 0.1 to 0.2 part of a leveling agent; and 33-45 parts of a solvent. The anti-burst electroplating primer disclosed by the invention can be used for the surface of a plastic base material such as a PET material, has the advantages of no burst in a free falling body with the height of 80cm and adhesive force of more than level 1, endows a subsequent electroplated layer with good adhesive force and reduces the burst problem of a product under pressure.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electroplating primers, in particular to an anti-cracking electroplating primer and a preparation method thereof. BACKGROUND

[0002] An electroplating primer is a kind of coating used on the surface of metal, plastic or other substrates, usually as a pretreatment coating for the electroplating process. Its main function is to provide good adhesion, uniformity and corrosion resistance for the subsequent electroplated layer (such as chromium plating, nickel plating, zinc plating, etc.), thereby improving the quality of the electroplated layer and the durability of the product.

[0003] Currently, there is a kind of UV electroplating primer, which uses a two-functional polyurethane acrylate to modify an epoxy acrylate resin as the main component, and the hardness of the primer is about 1H. Although this primer can meet the general protection requirements, it often has obvious shortcomings when applied to some soft products that require high flexibility, such as when the product is pinched or squeezed in actual use, the coating will produce many cracks, affecting the product quality. SUMMARY

[0004] In order to improve and reduce the cracking problem of the electroplating primer, the application provides an anti-cracking electroplating primer and a preparation method thereof.

[0005] In the first aspect, the application provides an anti-cracking electroplating primer, which adopts the following technical scheme: An anti-cracking electroplating primer comprises the following components in parts by weight: 8-12 parts of two-functional polyurethane acrylate; 20-25 parts of three-functional polyester acrylate; 10-15 parts of modified epoxy acrylate resin; 13-20 parts of UV monomer; 4-6 parts of photoinitiator; 0.1-0.2 parts of leveling agent; 33-45 parts of solvent.

[0006] By adopting the above technical scheme: 1. The three-functional polyester acrylate is used as the main resin, which gives the primer good flexibility and does not cause the film to color due to slow curing. 2. The two-functional polyurethane acrylate is compounded to provide sufficient plating performance. 3. The content of the UV monomer is reduced to reduce the curing shrinkage, thereby ensuring that the film has good flexibility on the surface of soft materials and is not prone to cracking.

[0007] Optionally, the photoinitiator is composed of photoinitiator 184 and photoinitiator BOK.

[0008] Optionally, the weight ratio of the photoinitiator 184 and the photoinitiator BOK is 2-3:2-3.

[0009] By adopting the technical scheme, the combination of the photoinitiator 184 and BOK can absorb ultraviolet light of different wave bands, and realize rapid curing of the primer.

[0010] Optionally, the organic solvent is composed of ethyl acetate, butyl acetate and butyl ether.

[0011] Optionally, the weight ratio of the ethyl acetate, butyl acetate and butyl ether is 20-25:10-15:3-5.

[0012] By adopting the technical scheme, the solvent combination of the ethyl acetate, butyl acetate and butyl ether fully dissolves each component and fully disperses, thereby improving the quality of the primer layer.

[0013] Optionally, the UV monomer is composed of trimethylolpropane triacrylate and hydroxyethyl methacrylate.

[0014] Optionally, the weight ratio of the trimethylolpropane triacrylate and hydroxyethyl methacrylate is 8-10:5-10.

[0015] By adopting the technical scheme, the trimethylolpropane triacrylate participates in the curing process, the viscosity can be adjusted to guarantee good workability, and the hydroxyethyl methacrylate provides excellent adhesion of the primer.

[0016] Optionally, the primer further comprises the following components in the weight fractions: Phosphorus pentoxide 1-5 parts; Methylcobalamin 0.3-0.6 parts.

[0017] By adopting the technical scheme, the phosphorus pentoxide and hydroxyethyl fat undergo a lipidization reaction to increase the acid value and compensate for the poor adhesion of the three-functional polyurethane; the methylcobalamin has an unstable cobalt-carbon bond, the cobalt-carbon bond is broken to form hydroxycobalamin under ultraviolet irradiation, the introduction of the hydroxyl group increases the elasticity and ductility of the coating, so that the coating is not easy to crack or peel off, and is not easy to brittle crack.

[0018] In a second aspect, the application provides a preparation method of an explosion-proof electroplating primer, which adopts the following technical scheme: A preparation method of an explosion-proof electroplating primer, comprising the following steps: S1, blending two-functional polyurethane acrylate, three-functional polyester acrylate, modified epoxy acrylate resin and UV monomer, and stirring and mixing at a speed of 1000-1200 rpm for 25-35 min to obtain a mixture A; S2, dissolving the photoinitiator and the auxiliary agent, and then blending the mixture A, the solvent and the photoinitiator and the auxiliary agent, and stirring and mixing at a speed of 600-1000 rpm for 10-20 min.

[0019] By adopting the technical scheme, the light initiator and the auxiliary agent are fully dissolved and then mixed with other components, so that the mixing effect is improved. The process has fewer steps and is simple and efficient, which is beneficial to the industrialized large-scale preparation of the primer. The prepared primer has good adhesion and good flexibility on the surface of soft material and is not easy to burst.

[0020] In a third aspect, the application provides a preparation method of the explosion-proof electroplating primer, which adopts the following technical scheme: The preparation method of the explosion-proof electroplating primer comprises the following steps: S1, blending phosphorus pentoxide, methylcobalamin and hydroxyethyl methacrylate, and stirring and mixing at a speed of 1000-1300 rpm for 40-50 min to obtain a mixture B; S2, blending the mixture B, difunctional polyurethane acrylate, trifunctional polyester acrylate, modified epoxy acrylate resin and trimethylolpropane triacrylate, and stirring and mixing at a speed of 1000-1200 rpm for 25-35 min to obtain a mixture C; S3, adding the dissolved light initiator and auxiliary agent and solvent into the mixture C, and stirring and mixing at a speed of 600-1000 rpm for 10-20 min.

[0021] By adopting the technical scheme, the phosphorus pentoxide and the hydroxyethyl methacrylate are first blended to occur lipidization reaction and improve the acid value. When mixed with other components, the prepared primer has better adhesion and flexibility.

[0022] In summary, the application has the following beneficial effects: 1. The electroplating primer of the application is compounded with difunctional polyurethane acrylate as the main body resin of trifunctional polyester acrylate, which not only gives the primer good flexibility and does not cause the film to be colored due to slow curing, but also provides sufficient plating property. At the same time, by reducing the content of UV monomer to reduce the curing shrinkage, the film on the surface of soft material has good flexibility and is not easy to burst. 2. In the primer of the application, the light initiator is trimethylolpropane triacrylate and methyl methacrylate. The trimethylolpropane triacrylate is involved in the curing process to adjust the viscosity and ensure good workability, and the methyl methacrylate provides excellent adhesion of the primer. 3. The primer of the application further comprises phosphorus pentoxide and methylcobalamin to improve flexibility and adhesion and further improve the easy burst of the primer Problem . DETAILED DESCRIPTION

[0023] The application will be further described in detail below in combination with examples. The sources of the components are as follows. The components other than the following special components are sourced from the market: The difunctional urethane acrylate was obtained from Zannan Resin (China) Co., Ltd., model EBECRYL 8807. The trifunctional polyester acrylate was obtained from Zannan Resin (China) Co., Ltd., model EBECRYL 546. The modified epoxy acrylate resin was obtained from Dongguan Inoue New Material Development Co., Ltd., model UV-2215. The trimethylolpropane triacrylate was obtained from Zannan Resin (China) Co., Ltd. The hydroxyethyl methacrylate was obtained from Shandong Chuangying Chemical Co., Ltd. The silicone leveling agent was obtained from Zannan Resin (China) Co., Ltd., model EBECRYL 1360.

[0024] Example 1

[0025] An anti-cracking electroplating primer, the components and their respective weights are shown in Table 1, and is prepared by the following steps: S1, blend the difunctional urethane acrylate, the trifunctional polyester acrylate, the modified epoxy acrylate resin, and the UV monomer (trimethylolpropane triacrylate and hydroxyethyl methacrylate), and mix at a stirring speed of 1000 rpm for 35 min to obtain mixture A; S2, add the photoinitiator 184, the photoinitiator BOK, and the auxiliary agent (silicone leveling agent) to the ethyl ester, mix and dissolve at a stirring speed of 1000 rpm for 10 min, and then blend with mixture A, butyl ester, and butyl ether, and mix at a stirring speed of 600 rpm for 20 min to obtain the anti-cracking electroplating primer.

[0026] Example 2

[0027] An anti-cracking electroplating primer, the components and their respective weights are shown in Table 1, and is prepared by the following steps: S1, blend the difunctional urethane acrylate, the trifunctional polyester acrylate, the modified epoxy acrylate resin, and the UV monomer (trimethylolpropane triacrylate and hydroxyethyl methacrylate), and mix at a stirring speed of 1100 rpm for 30 min to obtain mixture A; S2, add the photoinitiator 184, the photoinitiator BOK, and the auxiliary agent (silicone leveling agent) to the ethyl ester, mix and dissolve at a stirring speed of 1000 rpm for 10 min, and then blend with mixture A, butyl ester, and butyl ether, and mix at a stirring speed of 800 rpm for 15 min to obtain the anti-cracking electroplating primer.

[0028] Example 3

[0029] An anti-cracking electroplating primer, the components and their respective weights are shown in Table 1, and is prepared by the following steps: S1, blend the two functional polyurethane acrylate, three functional polyester acrylate, modified epoxy acrylate resin, UV monomer (trimethylolpropane triacrylate and hydroxyethyl methacrylate) and stir for 25 min at 1200 rpm to obtain mixture A; S2, add photoinitiator 184, photoinitiator BOK, and auxiliary agent (silicone leveling agent) to the ethyl ester, stir and dissolve for 10 min at 1000 rpm, then blend with mixture A, butyl ester, and butyl ether, and stir for 10 min at 1000 rpm to obtain the product.

[0030] Comparative Example 1

[0031] A plating primer, which differs from Example 2 in that an equal amount of modified epoxy acrylate resin is used instead of three functional polyester acrylate.

[0032] Comparative Examples 2-3 A plating primer, which differs from Example 2 in that the amount of photoinitiator is different, as shown in Table 1.

[0033] Table 1: Components and their weights (kg) in Examples 1-3 and Comparative Examples 1-3 Components Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Di-functional urethane acrylate 8 10 12 10 10 10 Tri-functional polyester acrylate 20 22 25 \ 22 22 Modified epoxy acrylate 10 13 15 35 13 13 Trimethylolpropane triacrylate 8 9 10 9 6 11 Hydroxyethyl methacrylate 5 8 10 8 4 11 Photoinitiator 184 2 2.5 3 2.5 2.5 2.5 Photoinitiator BOK 2 2.5 3 2.5 2.5 2.5 Silicone leveling agent 0.1 0.15 0.2 0.15 0.15 0.15 Ethyl ester 20 22 25 22 22 22 Butyl ester 10 13 15 13 13 13 Butyl ether 3 4 5 4 4 4 Example

[0034] A non-bursting plating primer, the components and their respective weights are shown in Table 2, and is prepared by the following steps: S1, blend phosphorus pentoxide, methylcobalamin, and hydroxyethyl methacrylate, and stir for 50 min at 1000 rpm to obtain mixture B; S2, blend mixture B, two functional polyurethane acrylate, three functional polyester acrylate, modified epoxy acrylate resin, and trimethylolpropane triacrylate, and stir for 30 min at 1100 rpm to obtain mixture C; S3, add photoinitiator 184, photoinitiator BOK, and auxiliary agent (silicone leveling agent) to the ethyl ester, stir and dissolve for 10 min at 1000 rpm, then blend with mixture C, butyl ester, and butyl ether, and stir for 15 min at 800 rpm to obtain the product.

[0035] Example 5

[0036] A non-bursting plating primer, the components and their respective weights are shown in Table 2, and is prepared by the following steps: S1, blend phosphorus pentoxide, methylcobalamin, and hydroxyethyl methacrylate, and stir for 45 min at 1200 rpm to obtain mixture B; S2, blend mixture B, difunctional polyurethane acrylate, trifunctional polyester acrylate, modified epoxy acrylate resin, trimethylolpropane triacrylate, stir and mix at 1100 rpm for 30 min to obtain mixture C; S3, add photoinitiator 184, photoinitiator BOK, and auxiliary agent (silicone leveling agent) to the ethyl ester, stir and mix at 1000 rpm for 10 min, then blend with mixture C, butyl ester, and butyl ether, stir and mix at 800 rpm for 15 min, and obtain the product.

[0037] Example 6

[0038] An anti-burst electroplating primer, the components and their respective weights are shown in Table 2, and is prepared by the following steps: S1, blend phosphorus pentoxide, methylcobalamin, and hydroxyethyl methacrylate, stir and mix at 1300 rpm for 40 min to obtain mixture B; S2, blend mixture B, difunctional polyurethane acrylate, trifunctional polyester acrylate, modified epoxy acrylate resin, trimethylolpropane triacrylate, stir and mix at 1100 rpm for 30 min to obtain mixture C; S3, add photoinitiator 184, photoinitiator BOK, and auxiliary agent (silicone leveling agent) to the ethyl ester, stir and mix at 1000 rpm for 10 min, then blend with mixture C, butyl ester, and butyl ether, stir and mix at 800 rpm for 15 min, and obtain the product.

[0039] Comparative Example 4

[0040] An anti-burst electroplating primer, which is different from Example 5 in that methylcobalamin is not added.

[0041] Comparative Example 5

[0042] An anti-burst electroplating primer, which is different from Example 5 in that phosphorus pentoxide is not added.

[0043] Table 2 Components and their weights (kg) in Examples 4-6 and Comparative Examples 4-5 Components Example 4 Example 5 Example 6 Comparative Example 4 Comparative Example 5 Phosphorous pentoxide 1 3 5 3 \ Methylcobalamin 0.3 0.45 0.6 \ 0.45 Di-functional urethane acrylate 10 10 10 10 10 Tri-functional polyester acrylate 22 22 22 22 22 Modified epoxy acrylate 13 13 13 13 13 Trimethylolpropane triacrylate 9 9 9 9 9 Hydroxyethyl methacrylate 8 8 8 8 8 Photoinitiator 184 2.5 2.5 2.5 2.5 2.5 Photoinitiator BOK 2.5 2.5 2.5 2.5 2.5 Silicone leveling agent 0.15 0.15 0.15 0.15 0.15 Ethyl ester 22 22 22 22 22 Butyl ester 13 13 13 13 13 Butyl ether 4 4 4 4 4

[0044] The electroplating primer prepared in the examples and comparative examples was subjected to the following performance tests, and the test results are recorded in Table 3.

[0045] 1. Anti-burst performance test: spray PP treatment agent (commercially available) and electroplating primer on the surface of a plastic bottle made of PET material in sequence, the coating film thickness of the primer is 25 μm, and the sample is placed in a UV aging chamber at a temperature of 50 °C and a UV energy of 500 mJ / cm 2The primer layer was cured by irradiating with lower ultraviolet light for 3 minutes. The vacuum plating was performed on the primer layer, and the UV-cured topcoat was sprayed on the vacuum plating. The topcoat was composed of difunctional aliphatic polyurethane acrylate, trimethylolpropane triacrylate, photoinitiator 184, photoinitiator MBF, ethyl ester, butyl ester, and butyl ether at a weight ratio of 25:10:2:2:20:5:5. The coating film thickness of the topcoat was 25 μm. The topcoat was leveled under the irradiation of an infrared lamp at 60 °C for 7 minutes, and the energy of UV curing was 400 mJ / cm2. 2 The topcoat film was formed by energy UV curing.

[0046] The plastic bottle was filled with water, and the water was dropped vertically at a height of 60 cm, 65 cm, 70 cm, 75 cm, 80 cm, 85 cm, 90 cm, 95 cm, 100 cm, 105 cm, and 110 cm, respectively. The height at which the coating did not burst was recorded. The higher the height, the better the anti-burst performance of the primer.

[0047] 2. Adhesion detection: detection was performed according to GB / T 9286-1998 “Paints and varnishes Cross-hatch test”.

[0048] Table 3. Performance detection results Item Resistance to popping height (cm) Adhesion rating (scale) Example 1 80 1 Example 2 80 1 Example 3 80 1 Example 4 95 0 Example 5 105 0 Example 6 100 0 Comparative Example 1 60 2 Comparative Example 2 \ 4 Comparative Example 3 65 1 Comparative Example 4 80 0 Comparative Example 5 100 1 As can be seen from Table 3, in Examples 1-3, the three-functional polyester acrylate was used as the main resin, and the content of the UV monomer was reduced, so that the anti-burst height of the coating was 80 cm. In Comparative Examples 1 and 3, the three-functional polyester acrylate was absent or the content of the UV monomer was increased, so that the anti-burst height of the coating was reduced to 60-65 cm, indicating that the primer of the present application has better anti-burst performance. In Comparative Example 2, the monomer content was reduced, resulting in incomplete curing of the primer coating, and no anti-burst height test data was obtained.

[0049] As can be seen from Table 3, Examples 4-6 differ from Example 2 in that they further contain phosphorus pentoxide and methylcobalamin. The anti-burst height is increased to more than 95 cm, and the adhesion is improved from level 1 to level 0, indicating that the anti-burst performance and adhesion of the prepared primer are both greatly improved.

[0050] The reason may be that the esterification reaction of phosphorus pentoxide and hydroxyethyl methacrylate increases the acid value, thereby improving the adhesion of the primer. Under light, the cobalt-carbon bond is broken to form hydroxycobalamin, and the introduction of hydroxyl group improves the elasticity and ductility of the primer, so that the paint film is not easy to crack, and the anti-burst performance is improved. In Examples 4-6, Example 5 is the best embodiment.

[0051] The difference between Example 5 and Comparative Examples 4 and 5 is that Comparative Example 4 does not contain methylcobalamin, and the anti-burst height is reduced to 80 cm. Comparative Example 5 does not contain phosphorus pentoxide, and the adhesion is reduced to level 1, and the anti-burst height is also decreased to a certain extent.

[0052] The embodiments are only illustrative of the present application, and are not intended to limit the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. An anti-crater electroplating primer, characterized by, The primer further comprises the following components in parts by weight: bifunctional polyurethane acrylate 8-12 parts; trifunctional polyester acrylate 20-25 parts; modified epoxy acrylate 10-15 parts; UV monomer 13-20 parts; photoinitiator 4-6 parts; leveling agent 0.1-0.2 parts; solvent 33-45 parts.

2. An anti-crater electroplating primer according to claim 1, wherein: The photoinitiator is composed of photoinitiator 184 and photoinitiator BOK.

3. An anti-crater electroplating primer according to claim 2, wherein: The weight ratio of the photoinitiator 184 and the photoinitiator BOK is 2-3:2-3.

4. An anti-crater electroplating primer according to claim 1, wherein: The organic solvent is composed of ethyl acetate, butyl acetate and butyl ether.

5. An anti-crater electroplating primer according to claim 4, wherein: The weight ratio of the ethyl acetate, butyl acetate and butyl ether is 20-25:10-15:3-5.

6. An anti-crater electroplating primer according to claim 1, wherein: The UV monomer is composed of trimethylolpropane triacrylate and hydroxyethyl methacrylate.

7. An anti-crater electroplating primer according to claim 6, wherein: The weight ratio of the trimethylolpropane triacrylate and the hydroxyethyl methacrylate is 8-10:5-10.

8. An anti-crater electroplating primer according to claim 6, wherein The primer further comprises the following components in parts by weight: phosphorus pentoxide 1-5 parts; methylcobalamin 0.3-0.6 parts.

9. A process for the preparation of the anti-cratering electroplating primer according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: S1, blend the bifunctional polyurethane acrylate, the trifunctional polyester acrylate, the modified epoxy acrylate and the UV monomer, and stir and mix at a speed of 1000-1200 rpm for 25-35 min to obtain a mixture A; S2, after dissolving the photoinitiator and the auxiliary agent, blend the mixture A and the solvent, and stir and mix at a speed of 600-1000 rpm for 10-20 min.

10. A method of preparing the anti-cratering electroplating primer of claim 8, characterized by, The method comprises the following steps: S1, blend the phosphorus pentoxide, the methylcobalamin and the hydroxyethyl methacrylate, and stir and mix at a speed of 1000-1300 rpm for 40-50 min to obtain a mixture B; S2, blend the mixture B, the bifunctional polyurethane acrylate, the trifunctional polyester acrylate, the modified epoxy acrylate and the trimethylolpropane triacrylate, and stir and mix at a speed of 1000-1200 rpm for 25-35 min to obtain a mixture C; S3, add the dissolved photoinitiator and auxiliary agent and the solvent to the mixture C, and stir and mix at a speed of 600-1000 rpm for 10-20 min.