Antistatic coating for single-sided circuit board, preparation method of antistatic coating and single-sided circuit board

Abstract

The invention relates to the technical field of circuit boards, in particular to an antistatic coating for a single-sided circuit board, a preparation method of the antistatic coating and the single-sided circuit board. The antistatic coating for the single-sided circuit board is prepared from the following raw materials in parts by weight: 35 to 45 parts of waterborne polyurethane resin, 8 to 12 parts of unsaturated polyester, 10 to 14 parts of cyclodextrin, 7 to 10 parts of graphite powder, 5 to 7 parts of flatting agent and 23 to 27 parts of water, the method has the advantage of reducing the electrostatic effect on the surface of the circuit board.

Description

Technical Field

[0001] The present application relates to the technical field of circuit boards, and in particular to an antistatic coating for a single-sided circuit board, a preparation method thereof, and the single-sided circuit board. Background Art

[0002] Single-sided circuit board is a type of printed circuit board. Single-sided circuit board refers to the most basic printed circuit board, where the parts are concentrated on one side and the wires are concentrated on the other side. It is often used to make relatively low-end machines. It has the advantages of convenient welding components, convenient heat dissipation treatment, and low cost.

[0003] Circuit boards are an indispensable core component of electronic products. With the development trend of electronic products towards integration, high density and high reliability, the design of the circuit boards used will become more compact, thin, short, multifunctional and intelligent, and the quality requirements for circuit boards will also become higher and higher.

[0004] When a circuit board is installed on an electrical appliance and is in operation, the electrostatic effect on its surface increases its ability to absorb dust. The accumulation of dust can easily lead to a decrease in the heat dissipation capacity of the circuit board, resulting in problems such as poor contact. Summary of the invention

[0005] In order to reduce the static electricity on the surface of a circuit board, the present application provides an antistatic coating for a single-sided circuit board, a preparation method thereof, and a single-sided circuit board.

[0006] In the first aspect, the present application provides an antistatic coating for a single-sided circuit board, which adopts the following technical solution: An antistatic coating for a single-sided circuit board comprises the following raw materials in parts by weight: 35-45 parts of waterborne polyurethane resin, 8-12 parts of unsaturated polyester, 10-14 parts of cyclodextrin, 7-10 parts of graphite powder, 5-7 parts of leveling agent and 23-27 parts of water.

[0007] By adopting the above technical solution, by adding unsaturated polyester and graphite powder to the antistatic coating, the unsaturated polyester is added as an electrostatic material, which can play its own semi-insulating and semi-conductive characteristics, and can slowly release the arc generated by the single-sided circuit board, greatly weakening the electrostatic effect on the surface of the single-sided circuit board; and the added graphite powder has a strong conductivity, which can cooperate with the unsaturated polyester to greatly reduce the electrostatic effect of the single-sided circuit board. However, unsaturated polyester is not miscible with water. The present application adds cyclodextrin, which is a hollow cylindrical structure that can embed guest molecules of a suitable size. Cyclodextrin can embed the unsaturated polyester, thereby improving its solubility in water and making the antistatic coating uniform in texture.

[0008] Preferably, the antistatic coating further comprises 0.5-0.7 parts by weight of a surfactant.

[0009] By adopting the above technical solution and adding a surfactant to the raw material, the unsaturated polyester can be accelerated to form smaller molecular bundles in water, so that it can be embedded in cyclodextrin faster and better.

[0010] Preferably, the surfactant is poloxamer and polyvinyl pyrrolidone, and the mass ratio of poloxamer to polyvinyl pyrrolidone is (0.8-1.2):1.

[0011] By adopting the above technical solution, when the surfactants poloxamer and polyvinyl pyrrolidone are added simultaneously, the effect of emulsifying and dispersing the unsaturated polyester is better.

[0012] Preferably, the graphite powder is modified graphite powder, and the modified graphite powder is modified by reacting the graphite powder with an aminosilane coupling agent or a silane coupling agent containing a double bond.

[0013] By adopting the above technical solution, the graphite powder is modified by a silane coupling agent, so that the compatibility between the graphite powder and the system can be improved, the surface tension between the graphite powder and the system can be reduced, and the tiny bubbles generated thereby can be greatly reduced, thereby improving the conductivity and thermal conductivity of the antistatic layer, and also reducing the roughness of the surface of the antistatic layer. By adopting a silane coupling agent containing an amino group or a double bond, intermolecular conjugation can be generated between the silane coupling agent and the unsaturated polyester, thereby making the compatibility of the system better and the integrity stronger; at the same addition amount, the conductivity of the unsaturated polyester and the graphite powder can be improved to a certain extent.

[0014] Preferably, the aminosilane coupling agent is one or more of N-aminoethyl-γ-aminopropyltrimethoxysilane, aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane and anilinemethyltriethoxysilane.

[0015] By adopting the above technical scheme, aminosilane coupling agents can theoretically use substances within this range to produce technical effects similar to those of the present application, which are not explored one by one in the examples of the present application.

[0016] Preferably, the double bond-containing silane coupling agent is one or more of acryloxymethyltrimethoxysilane, vinyltributylonoxime silane, γ-methacryloxypropyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane and vinyltriisopropoxysilane.

[0017] By adopting the above technical scheme, theoretically, the silane coupling agent containing double bonds can use substances within this range to produce technical effects similar to those of the present application, which are not explored one by one in the embodiments of the present application.

[0018] Preferably, the leveling agent is polydimethylsiloxane.

[0019] By adopting the above technical solution, polydimethylsiloxane is a hydrophobic silicone material with a small surface tension. By adding polydimethylsiloxane, the flowability of the film-forming component is improved, which is conducive to the smoothness of the film. Polydimethylsiloxane has a certain thermal conductivity, which ensures the thermal conductivity of the antistatic layer. At the same time, its hydrophobicity makes it easy for the film-forming component to be separated on the surface of the film-forming component when it is coated on the surface of the single-sided circuit board, so that the water is easy to dry. Because the dried water is on the surface, the surface of the antistatic layer is smooth and it is not easy to leave water holes.

[0020] In a second aspect, the present application provides a method for preparing an antistatic coating for a single-sided circuit board, using the following technical solution: A method for preparing an antistatic coating for a single-sided circuit board comprises the following preparation steps: Add cyclodextrin into water, stir evenly, then add unsaturated polyester, stir at a speed of 4500-5500r / min, then stir at a speed of 1500-2500r / min, then add waterborne polyurethane resin, graphite powder and leveling agent, continue to stir evenly, and obtain antistatic coating for single-sided circuit boards.

[0021] By adopting the above technical solution, unsaturated polyester and cyclodextrin are added into water, and through high-speed stirring, the unsaturated polyester is dispersed into molecular bundles in water, so that it can be embedded by cyclodextrin, thereby improving the solubility and dispersion of the unsaturated polyester in water and making the solution more uniform.

[0022] In a third aspect, the present application provides a single-sided circuit board, which adopts the following technical solution: A single-sided circuit board comprises an antistatic layer, wherein the antistatic coating used for the antistatic layer is the antistatic coating for the single-sided circuit board according to any one of claims 1 to 7.

[0023] By adopting the above technical solution, the single-sided circuit board prepared in the present application has strong anti-static ability and good thermal conductivity, which can greatly extend its life.

[0024] In summary, the present application includes at least one of the following beneficial technical effects: 1. By adding unsaturated polyester and graphite powder to the antistatic coating, the unsaturated polyester can be added as an electrostatic material to give play to its semi-insulating and semi-conductive properties, and can slowly release the arc generated by the single-sided circuit board, greatly weakening the electrostatic effect on the surface of the single-sided circuit board; and the added graphite powder has a strong conductivity, which can cooperate with the unsaturated polyester to greatly reduce the electrostatic effect of the single-sided circuit board. However, unsaturated polyester is not miscible with water. This application adds cyclodextrin, which is a hollow cylindrical structure that can embed guest molecules of a suitable size. Cyclodextrin can embed the unsaturated polyester, thereby improving its solubility in water and making the antistatic coating uniform in texture.

[0025] 2. The adhesion level of the single-sided circuit boards prepared in this application is 1-3, and the resistivity can reach (0.70-0.80) x10 8 Ω·m, and the surface roughness is 0.15μm or less, and the lowest can reach 0.08μm, and the thermal conductivity can be controlled at 2.4-2.7W / (m·k); it shows that the antistatic coating prepared in the present application can have good antistatic ability and heat dissipation ability, and can extend the service life of the single-sided circuit board. DETAILED DESCRIPTION

[0026] The present application is further described in detail below in conjunction with the specific contents.

[0027] raw material The raw materials used in the preparation examples of this application are all purchased from the market, and the cyclodextrin is β-cyclodextrin, food grade; the particle size of the graphite powder is 1250 mesh; the model of polydimethylsiloxane is PMX, and the kinematic viscosity at 40°C is 1000cst; the model of unsaturated polyester is methyl vinyl MQ silicone resin, model SH-5201; the model of water-based polyurethane resin is APU-3330, and the purchase manufacturer is Dongguan Ruiqi Industrial Investment Co., Ltd. Example

[0028] Example 1 An antistatic coating for a single-sided circuit board, the raw materials and the amounts of the raw materials are shown in Table 1, and the preparation method is as follows: According to the dosage in Table 1, cyclodextrin was added to water, and after being stirred evenly, unsaturated polyester was added, and stirred at a speed of 4000 r / min for 20 minutes, and then stirred at a low speed of 2000 r / min for 10 minutes, and then water-based polyurethane resin, graphite powder and leveling agent were added, and stirring was continued to be evenly obtained to obtain an antistatic coating for a single-sided circuit board; Wherein, the leveling agent is polydimethylsiloxane.

[0029] Table 1 Raw materials and amounts of raw materials in Example 1 (kg) Waterborne polyurethane resin 40 Unsaturated polyester 10 Cyclodextrin 12 Graphite powder 6 Leveling agent 6 water 25 Example 2 An antistatic coating for a single-sided circuit board is different from Example 1 in that the raw materials further include 0.6 kg of poloxamer and polyvinyl pyrrolidone, the mass ratio of poloxamer to polyvinyl pyrrolidone is 1:1, and the remaining steps are the same as those in Example 1.

[0030] Example 3 An antistatic coating for a single-sided circuit board is different from Example 1 in that the raw materials further include 0.6 kg of poloxamer, and the remaining steps are the same as those of Example 1.

[0031] Example 4 An antistatic coating for a single-sided circuit board is different from Example 1 in that the raw materials also include 0.6 kg of polyvinyl pyrrolidone, and the remaining steps are the same as those of Example 1.

[0032] Example 5 An antistatic coating for a single-sided circuit board, which is different from Example 2 in that its graphite powder is modified graphite powder of equal mass, and the specific preparation method of the modified graphite powder is as follows: 1 kg of graphite powder was dispersed in 10 kg of a mixture of water and ethanol, with the volume ratio of water to ethanol being 1:1, and then 0.8 kg of a silane coupling agent was added, wherein the silane coupling agent was aminopropyltriethoxysilane, and the temperature was raised to 70°C, and the mixture was stirred for reaction for 15 hours, and then filtered and dried to obtain modified graphite powder.

[0033] Example 6 An antistatic coating for a single-sided circuit board is different from Example 5 in that when preparing its modified graphite powder, its silane coupling agent is vinyl triethoxysilane of equal mass, and the remaining steps are the same as Example 5.

[0034] Comparative Example Comparative Example 1 An antistatic coating for a single-sided circuit board is different from Example 1 in that the unsaturated polyester in the raw material is replaced by an aqueous polyurethane resin of equal mass, and the remaining steps are the same as those in Example 1.

[0035] Comparative Example 2 An antistatic coating for a single-sided circuit board, which is different from Example 1 in that its preparation method is as follows: According to the dosage in Table 1, cyclodextrin, unsaturated polyester, water-based polyurethane resin, graphite powder, leveling agent and water were mixed, stirred at a speed of 4000 r / min for 20 minutes, and then stirred at a low speed of 2000 r / min to obtain an antistatic coating for a single-sided circuit board.

[0036] Comparative Example 3 An antistatic coating for a single-sided circuit board is different from Example 1 in that cyclodextrin is not added to the raw materials, and the remaining steps are the same as those of Example 1.

[0037] Application Examples Application Examples 1-6 A single-sided circuit board of application example 1-6 includes an antistatic layer, and the preparation method of the antistatic layer on the single-sided circuit board is as follows: The single-sided circuit board is rinsed with water spray for 2 minutes, then rinsed with a 25-30°C cleaning agent for 10 minutes, and then rinsed with water spray for 5 minutes, and dried naturally; then a soft brush is dipped in antistatic coating, and the antistatic coating is applied to the surface of the naturally dried single-sided circuit board, and then placed in an oven and dried at 45°C to form an antistatic layer with a film thickness of 0.2 mm, to obtain a single-sided circuit board; wherein the antistatic coatings used in Application Examples 1-6 correspond to the antistatic coatings of Examples 1-6, respectively.

[0038] The preparation method of the cleaning agent is as follows: S1, weigh 8kg of borax, 7kg of 30wt% sodium hydroxide, 20kg of hydrogen peroxide, and 20kg of water, stir and react at 10°C for 1h to obtain a reactant; S2. Add 7kg 30wt% sodium hydroxide, 12kg sodium triphosphate, 12kg sodium tripolyphosphate, 3kg sodium dodecyl sulfate, 3kg sodium secondary alkyl sulfonate, and 40kg water to the reactant, and stir at 25°C for 1h to prepare a cleaning agent, and its pH is measured to be 12.

[0039] Application Comparative Examples 1-3 A single-sided circuit board using comparative examples 1-3 is different from application example 1 in that the antistatic coatings used in comparative examples 1-3 correspond to comparative examples 1-3, and the remaining steps are the same as those in application example 1.

[0040] Performance testing Detection method / test method An antistatic coating for a single-sided circuit board was prepared according to the preparation method of Examples 1-6 and Comparative Examples 1-3, and then a single-sided circuit board was prepared according to the method of Application Examples 1-6 and Comparative Examples 1-3. Then, the prepared single-sided circuit board was tested by the following method, and the test results are shown in Table 2.

[0041] Adhesion ability test: refer to the test method in GB / T1720-1979 for testing; Antistatic performance: Refer to the test method in HG / T3331-2012 to test the surface resistivity of the single-sided circuit board in dry state (air humidity is 40%); Surface smoothness test: Refer to GB / T14234-1993 to test the surface roughness of single-sided circuit boards.

[0042] Table 2 Test results of application examples 1-6 and comparative examples 1-3 Through application examples 1-6 and comparative examples 1-3, as well as the test data in Table 2, it can be seen that the adhesion level of the single-sided circuit boards prepared in this application is 1-3, and the resistivity can reach (0.70-0.80) x10 8 Ω·m, and the surface roughness is 0.15μm or less, and the lowest can reach 0.08μm, and the thermal conductivity can be controlled at 2.4-2.7W / (m·k); it shows that the antistatic coating prepared in the present application can have good antistatic ability and heat dissipation ability, and can extend the service life of the single-sided circuit board.

[0043] By adding unsaturated polyester and graphite powder to the antistatic coating, the unsaturated polyester is added as an electrostatic material, which can give play to its own semi-insulating and semi-conductive properties, and can slowly release the arc generated by the single-sided circuit board, greatly weakening the electrostatic effect on the surface of the single-sided circuit board; and the added graphite powder has a strong conductivity, which can cooperate with the unsaturated polyester, greatly reducing the electrostatic effect of the single-sided circuit board. However, the unsaturated polyester is not miscible with water. The present application adds cyclodextrin, which is a hollow cylindrical structure and can embed guest molecules of a size suitable for it. The unsaturated polyester and cyclodextrin are added to water, and through high-speed stirring, the unsaturated polyester is dispersed into molecular beams in the water, so that it can be embedded by cyclodextrin, thereby improving the dissolution and dispersion of the unsaturated polyester in water, and making the solution more uniform. This can be verified by the test data of Application Example 1 and Application Comparative Examples 1-3. Without adding cyclodextrin, after drying, the antistatic layer is likely to form tiny bubbles inside the antistatic layer due to its incompatibility with the system, thereby increasing its thermal conductivity and reducing its semi-conductive performance.

[0044] On this basis, by adding a surfactant to the raw material, the unsaturated polyester can be accelerated to form smaller molecular bundles in water, so that it can be embedded in cyclodextrin faster and better. This can be verified by the test data of application examples 1-4. And when the surfactant is poloxamer and polyvinyl pyrrolidone added at the same time, the effect of emulsifying and dispersing the unsaturated polyester is better.

[0045] It can be seen from the test data of Application Example 2 and Application Examples 5-6 that by modifying the graphite powder with a silane coupling agent, the compatibility between the graphite powder and the system can be improved, the surface tension between the graphite powder and the system can be reduced, and the tiny bubbles generated thereby can be greatly reduced, thereby improving the conductivity and thermal conductivity of the antistatic layer, and also reducing the roughness of the surface of the antistatic layer. In addition, by using a silane coupling agent containing an amino group or a double bond, intermolecular conjugation can be generated between the silane coupling agent and the unsaturated polyester, thereby making the compatibility of the system better and the integrity stronger; at the same addition amount, the conductivity of the unsaturated polyester and the graphite powder can be improved to a certain extent.

[0046] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. An antistatic coating for a single-sided circuit board, characterized in that: The invention comprises the following raw materials in parts by weight: 35-45 parts of waterborne polyurethane resin, 8-12 parts of unsaturated polyester, 10-14 parts of cyclodextrin, 7-10 parts of graphite powder, 5-7 parts of leveling agent and 23-27 parts of water.

2. The antistatic coating for a single-sided circuit board according to claim 1, characterized in that: The antistatic coating further comprises 0.5-0.7 parts by weight of a surfactant.

3. The antistatic coating for a single-sided circuit board according to claim 2, characterized in that: The surfactants are poloxamer and polyvinyl pyrrolidone, and the mass ratio of poloxamer to polyvinyl pyrrolidone is (0.8-1.2):

1.

4. The antistatic coating for a single-sided circuit board according to claim 1, characterized in that: The graphite powder is modified graphite powder, and the modified graphite powder is modified by reacting the graphite powder with an aminosilane coupling agent or a silane coupling agent containing a double bond.

5. The antistatic coating for a single-sided circuit board according to claim 4, characterized in that: The aminosilane coupling agent is one or more of N-aminoethyl-γ-aminopropyltrimethoxysilane, aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane and anilinemethyltriethoxysilane.

6. The antistatic coating for a single-sided circuit board according to claim 4, characterized in that: The double bond-containing silane coupling agent is one or more of acryloxymethyltrimethoxysilane, vinyltributylonoximesilane, γ-methacryloxypropyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane and vinyltriisopropoxysilane.

7. The antistatic coating for a single-sided circuit board according to claim 4, characterized in that: The leveling agent is polydimethylsiloxane.

8. A method for preparing an antistatic coating for a single-sided circuit board according to any one of claims 1 to 7, characterized in that: It comprises the following preparation steps: Add cyclodextrin into water, stir evenly, then add unsaturated polyester, stir at a speed of 4500-5500r / min, then stir at a speed of 1500-2500r / min, then add waterborne polyurethane resin, graphite powder and leveling agent, continue to stir evenly, and obtain antistatic coating for single-sided circuit boards.

9. A single-sided circuit board, characterized in that: It comprises an antistatic layer, and the antistatic coating used in the antistatic layer is the antistatic coating for the single-sided circuit board according to any one of claims 1-7.

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