Solder resist ink resin for foldable multilayer circuit board

Abstract

The present invention belongs to the technical field of polymer synthesis, and provides a solder resist ink resin for a foldable multilayer circuit board. A house-made epoxy resin intermediate is used, the house-made epoxy resin intermediate can be subjected to a ring-opening reaction with an acrylic monomer and then react with tetrahydrophthalic anhydride or hexahydrophthalic anhydride, and in the finally obtained product, a benzene ring in the house-made epoxy resin intermediate provides rigidity and high-temperature resistance, and the long chain segment of the side chain provides flexibility and yellowing resistance, and thus the prepared PCB solder resist ink resin has a better high-temperature resistance and yellowing resistance.

Description

A solder resist ink resin for foldable multi-layer circuit board TECHNICAL FIELD

[0001] The present application belongs to the technical field of polymer synthesis, and specifically relates to a solder resist ink resin for foldable multi-layer circuit board. BACKGROUND

[0002] PCB ink is an ink layer coated on a PCB, which can protect the circuit, and the core material composition is an organic polymer with certain viscosity, which is called PCB solder resist ink resin. In recent years, with the rapid development of mobile phones, notebooks and outdoor wearable electronic products, the requirements for the size and flexibility of PCBs carrying chips are becoming higher and higher. Traditional PCBs do not have flexibility, so based on this requirement, in addition to the good flexibility of PCBs, the ink used for PCBs also needs to have considerable flexibility, which puts forward new requirements for the core composition, i.e. high molecular polymer. In addition to the same excellent high temperature resistance and easy development performance as traditional PCB solder resist ink resin, it also needs to have flexibility to be applied in the coating process of PCB.

[0003] After searching, a Chinese invention patent: a PCB solder resist ink resin and a preparation method thereof (publication number CN113174030A, publication date 2021.07.27) discloses a PCB solder resist ink resin, which comprises the following components in percentage by mass: 10-25% of acrylic acid monomer, 25-40% of epoxy resin, 6-10% of organic acid, 5-20% of special intermediate, and 30-60% of solvent. The special intermediate is obtained by the following steps: dihydric alcohol is reacted with maleic anhydride or tetrahydrophthalic anhydride at 80 DEG C for 0.5-2 h, then the temperature is lowered to 45-60 DEG C, isocyanate is added, and the reaction is carried out for 1-3 h. The input amount of dihydric alcohol is 10-20% by mass, the input amount of maleic anhydride or tetrahydrophthalic anhydride is 20-30% by mass, and the input amount of isocyanate is 50-60% by mass. Although the application also uses a special monomer, the monomer in the scheme only increases the flexibility of the product, and does not well solve the high temperature resistance performance.

[0004] Therefore, there is an urgent need for a PCB solder resist ink resin and a preparation method thereof which can improve flexibility while maintaining excellent high temperature resistance and easy development performance to solve the above technical problems. SUMMARY

[0005] 1. Technical problems to be solved by the application

[0006] The purpose of the present application is to solve the problem of uneven heating of the existing heat collector under sunlight irradiation.

[0007] 2. Technical solutions

[0008] To achieve the above object, the technical scheme provided by the present application is as follows:

[0009] The solder resist resin for the foldable multilayer circuit board comprises the following components (calculated in percentage by mass)

[0010] 10-25% of acrylic monomer, 25-40% of epoxy resin, 6-10% of anhydride, 5-20% of isocyanate, and 30-60% of solvent, wherein the epoxy resin is a self-made epoxy resin intermediate with the following structure:

[0011] Preferably, the acrylic monomer is an acrylic monomer and / or a methacrylic monomer.

[0012] Preferably, the isocyanate is IPDI or HDI or isocyanate acrylate.

[0013] Preferably, the anhydride is one or more of maleic anhydride, tetrahydrophthalic anhydride, succinic anhydride, dimethylolbutyric anhydride, and hexahydrophthalic anhydride.

[0014] Preferably, the solvent is one or more of DBE, No. 150 solvent oil, and DCAC.

[0015] A preparation method of the solder resist resin for the foldable multilayer circuit board comprises the following steps:

[0016] S1, heating a reaction kettle to 90-150℃, adding a solvent, adding an acrylic monomer, an epoxy resin, and a catalyst within 1-5h, and maintaining the temperature for 1-10h, wherein the epoxy resin is a self-made epoxy resin intermediate;

[0017] S2, adding an anhydride, controlling the reaction temperature to be 90-130℃, and reacting for 2-6h;

[0018] S3, adding IPDI or HDI or isocyanate acrylate, controlling the reaction temperature to be 40-110℃, and reacting for 1-5h.

[0019] Preferably, the catalyst in step S1 is triphenylphosphine or dimethyl aniline or triethylamine.

[0020] Preferably, in step S1, the acrylic monomer and the epoxy resin are added within 2h, and the temperature is maintained for 10h; in step S2, the reaction time is 5h.

[0021] Preferably, the preparation process of the self-made epoxy resin intermediate is as follows:

[0022] The reaction kettle is added with epoxy bisphenol A type resin, the temperature is raised to 130-150 DEG C, caprolactone and catalyst are added, and the reaction time is controlled to be 3-8h;

[0023] The mass ratio of the epoxy bisphenol A type resin to the caprolactone is 1:1-1:4, and the catalyst accounts for 1 / 10,000 to 1 / 50,000 of the total mass ratio of the epoxy bisphenol A type resin to the caprolactone.

[0024] Preferably, the catalyst is stannous octoate or monobutyl tin oxide, and the caprolactone is added dropwise for 0.5-3h. 3. Beneficial effects

[0025] Compared with the prior art, the technical scheme provided in the application has the following beneficial effects:

[0026] The self-made epoxy resin intermediate can be subjected to ring-opening reaction with an acrylic monomer, and then subjected to reaction with tetrahydrophthalic anhydride or hexahydrophthalic anhydride, and in the final product, the benzene ring in the self-made epoxy resin intermediate provides rigidity and high-temperature resistance, and the long-chain segment of the side chain provides flexibility and yellowing resistance, and therefore, the prepared PCB solder resist resin has better high-temperature resistance and yellowing resistance. BRIEF DESCRIPTION OF DRAWINGS

[0027] Fig. 1 is a schematic view of the molecular structure of the self-made epoxy resin intermediate of the application;

[0028] Fig. 2 is a flexible circuit board obtained by using the resin prepared in application example 1. DETAILED DESCRIPTION

[0029] In order to enable personnel in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work should fall within the scope of protection of the present application.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be combined. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0031] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not intended to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0032] In addition, in addition to indicating the orientation or positional relationship, the above-mentioned partial terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific circumstances.

[0033] In addition, the terms "mount", "set", "provided with", "connected", "connected", "sleeved" should be broadly understood. For example, it can be a fixed connection, a detachable connection, or a monolithic structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or internal communication between two devices, elements or components. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0034] It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0035] Embodiment 1

[0036] The present embodiment provides a PCB solder resist ink resin, which comprises the following components: 15.8 kg of acrylic monomer, 30 kg of self-made epoxy intermediate, 0.2 kg of triethylamine, 10 kg of maleic anhydride, 5 kg of HDI, 3 kg of IPDI and 36 kg of DCAC solvent.

[0037] The preparation method of the PCB solder resist ink resin of the embodiment is as follows:

[0038] S1, heat the reaction kettle to 100℃, add DCAC solvent, add self-made epoxy intermediate, triethylamine, and drop acrylic acid dropwise for 2h, and keep warm for 10h;

[0039] S2, add maleic anhydride, and control the reaction temperature to be 130℃ for 5h;

[0040] S3, add IPDI and HDI, and control the reaction temperature to be 80℃ for 5h.

[0041] Example 2

[0042] The PCB solder resist ink resin provided in the embodiment comprises the following components: 14.8kg of acrylic monomer, 28kg of self-made epoxy resin intermediate, 0.2kg of triphenylphosphine, 9kg of tetrahydrophthalic anhydride, 10kg of HDI, 2kg of IPDI, and 36kg of DBE solvent.

[0043] S1, heat the reaction kettle to 120℃, add DBE solvent, add self-made epoxy resin intermediate and triphenylphosphine, drop acrylic acid dropwise for 2h, and keep warm for 10h;

[0044] S2, add tetrahydrophthalic anhydride, and control the reaction temperature to be 130℃ for 5h;

[0045] S3, add IPDI or HDI, and control the reaction temperature to be 80℃ for 5h.

[0046] Comparative Example 1

[0047] The PCB solder resist ink resin provided in the embodiment comprises the following components: 15.8kg of acrylic acid, 30kg of bisphenol A epoxy resin (commercially available, trade name Changchun 188 epoxy resin), 0.2g of triethylamine, 10kg of maleic anhydride, 5kg of HDI, 3kg of IPDI, and 36kg of DCAC solvent.

[0048] The preparation method of the PCB solder resist ink resin of the embodiment is as follows:

[0049] S1, put DCAC into the reaction kettle, heat to 100℃, add 3,4-epoxycyclohexyl carboxylic acid-3',4'-epoxycyclohexyl methyl ester, triethylamine, and drop acrylic acid dropwise for 2h, and keep warm for 10h;

[0050] S2, add maleic anhydride, heat to 130℃, and react for 5h;

[0051] S3, cool to 80℃, add HDI and IPDI, and react for 5h.

[0052] The comparative example is the same as example 1 in terms of the ratio of raw materials and the synthesis route, except that the epoxy resin part is different.

[0053] Comparative example 2

[0054] The example provides a PCB solder resist ink resin, which comprises the following components: 16.5 kg of acrylic acid, 32 kg of bisphenol A epoxy resin (marketed as Nanya 128 epoxy resin), 0.2 kg of triphenylphosphine, 11 kg of tetrahydrophthalic anhydride, 5 kg of HDI, 2 kg of IPDI, and 36 kg of DBE solvent.

[0055] The preparation method of the PCB solder resist ink resin of the example is as follows:

[0056] S1, DBE is put into a reaction kettle, heated to 120°C, bis((3,4-epoxycyclohexyl) methyl) adipate, triphenylphosphine, and acrylic acid are added dropwise, the dropwise addition is performed for 2 h, and the temperature is kept for 10 h;

[0057] S2, tetrahydrophthalic anhydride is added, the temperature is raised to 130°C, and the reaction is performed for 5 h;

[0058] S3, the temperature is lowered to 80°C, HDI and IPDI are added, and the reaction is performed for 5 h.

[0059] The comparative example is the same as example 2 in terms of the synthesis route, except that the epoxy resin part is different, and the ratio of raw materials is different.

[0060] The high-temperature resistance, developing performance, and flexibility of examples 1 and 2 and comparative examples 1 and 2 are detected, and the detection results are shown in Table 1.

[0061] Table 1 Comparative data of product effects of examples 1 and 2 and comparative examples 1 and 2

[0062] The high-temperature resistance test method is as follows: the main resin is uniformly stirred with a fixed amount of active monomer, photoinitiator, epoxy resin, epoxy curing agent, and leveling agent, uniformly coated on a PCB copper foil, placed in an 80°C oven for 0.5 hours, then baked at 160°C for 2 hours, then placed in a 280°C tin furnace for 10 seconds, and taken out. After repeating three times, observe whether the copper foil surface cracks.

[0063] The developing time test method is as follows: the main resin is uniformly stirred with a fixed amount of active monomer, photoinitiator, epoxy resin, epoxy curing agent, and leveling agent, uniformly coated on a PCB copper foil, placed in an 80°C oven for 0.5 hours, then exposed by an exposure machine, then sprayed on the copper foil with 1% sodium carbonate aqueous solution under a pressure of 2 kg / cm 2 When the pattern on the copper foil is completely developed, the time is recorded.

[0064] The flexibility and bending resistance test method is as follows: fold the copper foil in half at 180 degrees, then unfold and flatten, repeat several times, and record the number of folds when the coating on the copper foil cracks.

[0065] As can be seen from the technical effects of the above examples and comparative examples, the PCB solder resist ink resin of the present application, when using a special epoxy resin as a raw material, compared to the commonly used commercially available epoxy resin, can ensure the performance of the ink resistant to high temperature, shorten the developing time, and greatly improve the flexibility and bending resistance. This is because the self-made epoxy resin intermediate used in the present application can undergo ring-opening reaction with acrylic monomer, and then react with tetrahydrophthalic anhydride or hexahydrophthalic anhydride. In the final product, the benzene ring in the self-made epoxy resin intermediate provides rigidity and high temperature resistance, and the long chain segment of the side chain provides flexibility and yellowing resistance. Therefore, the PCB solder resist ink resin prepared has better high temperature resistance and yellowing resistance.

[0066] The above examples only express some embodiments of the present application, which are described in detail and specifically, but should not be understood as limiting the scope of the present application. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A solder resist resin for a foldable multilayer circuit board, characterized by: The components include the following (calculated in percentage of mass) 10-25% of acrylic monomer, 25-40% of epoxy resin, 6-10% of anhydride, 5-20% of isocyanate, 30-60% of solvent, wherein the epoxy resin is a self-made epoxy resin intermediate, and the structure is as follows:

2. The solder resist ink resin for a foldable multi-layer circuit board according to claim 1, characterized by: The acrylic monomer is an acrylic monomer and / or a methacrylic monomer.

3. The solder resist ink resin for a foldable multi-layer circuit board according to claim 1, characterized by: The isocyanate is IPDI or HDI or isocyanate acrylate.

4. The solder resist ink resin for a foldable multi-layer circuit board according to claim 1, characterized by: The anhydride is one or more of maleic anhydride, tetrahydrophthalic anhydride, succinic anhydride, dimethylol butyric anhydride, and hexahydrophthalic anhydride.

5. The solder resist ink resin for a foldable multi-layer circuit board according to claim 1, characterized by: The solvent is one or more of DBE, No. 150 solvent oil, and DCAC.

6. A method for preparing a solder resist ink resin for a foldable multilayer circuit board according to any one of claims 1-5, characterized in that, The steps include the following: S1, heating the reaction kettle to 90-150℃, adding a solvent, adding an acrylic monomer, an epoxy resin, and a catalyst within 1-5h, the holding time being 1-10h, the epoxy resin being a self-made epoxy resin intermediate; S2, adding an anhydride, the reaction time being 2-6h, the reaction temperature being controlled to 90-130℃; S3, adding IPDI or HDI or isocyanate acrylate, the reaction time being 1-5h, the reaction temperature being controlled to 40-110℃.

7. The method for preparing a solder resist ink resin for a foldable multilayer circuit board according to claim 6, characterized in that: The catalyst in step S1 is triphenylphosphine or dimethyl aniline or triethylamine.

8. The method for preparing a solder resist ink resin for a foldable multilayer circuit board according to claim 6, characterized in that: In step S1, the acrylic monomer and the epoxy resin are added within 2h, and the holding time is 10h; in step S2, the reaction time is 5h.

9. The method for preparing a solder resist ink resin for a foldable multilayer circuit board according to claim 6, characterized in that: The preparation process of the self-made epoxy resin intermediate is as follows: Into the reaction kettle, add an epoxy bisphenol A type resin, raise the temperature to 130-150℃, add caprolactone and a catalyst, and control the reaction time to be 3-8h; The mass ratio of the epoxy bisphenol A type resin to the caprolactone is 1:1-1:4, and the catalyst accounts for 1 / 10,000 to 1 / 50,000 of the total mass ratio of the epoxy bisphenol A type resin to the caprolactone.

10. The method for preparing a solder resist ink resin for a foldable multilayer circuit board according to claim 9, characterized in that: The catalyst is stannous octoate or monobutyl tin oxide, and the time for dropping the caprolactone is 0.5-3h.

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