A UV-curable electronic protective coating and its preparation method and application

Abstract

The present invention discloses a UV-curable electronic protective coating and a preparation method and application thereof, belonging to the technical field of protective coating and its preparation. The present invention obtains a UV-curable protective coating by synthesizing two new resins, a vinyl elastomer and a heat-resistant active end-group toughening agent, and compounding them with an active diluent, a accelerator, a flame retardant, and an initiator. The coating can realize the protective function of the electronic circuit after curing, and has the advantages of high construction efficiency, fast molding speed, good stability, high toughness, lower energy consumption, etc. compared with the existing technical route of pasting covering film.

Description

Technical Field

[0001] The invention relates to an ultraviolet curing electronic protective coating and a preparation method and application thereof, belonging to the technical field of protective coating and preparation thereof. Background Art

[0002] Flexible copper-clad laminates are often made of copper-clad polyimide substrates that are etched. In order to protect the circuits from damage after etching, a protective film is often required for pasting and protection. This protective film conventionally uses polyimide film as the base, and is coated with about 40 microns of epoxy resin adhesive on one side. Although this process is stable and mature, the higher cost of polyimide film and the poor stability of epoxy resin adhesive still leave room for optimization of this technical route. At the same time, the pasting and curing of the protective film will also take up a large plant space and consume a certain amount of energy. Therefore, if a protective coating is used to spray the etched film and a protective film is formed by UV curing, on the one hand, costs can be reduced, and on the other hand, production efficiency can be improved; however, conventional UV-curing coatings cannot achieve the high toughness, high adhesion and other performance requirements required by the protective film, and special modification processes are required to optimize its performance to meet the requirements for the use of the protective film. Summary of the invention

[0003] In view of the above technical problems existing in the prior art, the present invention provides a UV-curable electronic protective coating and a preparation method and application thereof, so as to achieve the purpose of quickly forming an electronic circuit protective layer with low energy consumption.

[0004] The technical solution of the present invention:

[0005] One of the purposes of the present invention is to provide a method for preparing a UV-curable electronic protective coating, the method comprising the following steps:

[0006] Step 1, using epoxy resin as raw material, polycondensing with polyether polyol under the action of a catalyst to increase the molecular weight, and then using an allyl raw material to end-cap to obtain a vinyl elastomer;

[0007] Step 2, using polyetheramine, bismaleimide resin, triallyl isocyanurate and diallyl bisphenol A as raw materials, and obtaining a heat-resistant active terminal toughening agent through Michael addition and polycondensation reaction;

[0008] Step 3, dissolving the vinyl elastomer and the heat-resistant active terminal toughening agent in the active diluent, adding the accelerator, the flame retardant and the initiator, mixing at room temperature in the dark, and obtaining the electronic protective coating.

[0009] It is further defined that the molar ratio of the epoxy resin, the polyether polyol and the allyl raw material in step 1 is 1:(0.3-0.35):(0.65-0.7).

[0010] It is further defined that the amount of the catalyst used in step 1 is 0.3-0.35 wt % of the epoxy resin.

[0011] It is further defined that in step 1, the epoxy resin is composed of AG80, E51 and MF-2133 in a molar ratio of 1:(0.3-0.35):(0.65-0.7).

[0012] It is further defined that in step 1, the allyl raw material consists of acrylic acid and methacrylic acid in a molar ratio of 1:(0.5-0.6).

[0013] It is further defined that the number average molecular weight of the polyether polyol in step 1 is 1000.

[0014] It is further defined that the catalyst in step 1 is triethylamine.

[0015] It is further defined that the operation process of step 1 is: dissolving the epoxy resin and the polyether polyol in butyl acetate, adding 1 / 2 mass of triethylamine, heating to 130°C and reflux reaction for 6 hours, then cooling to 105°C, dripping the mixture of the allyl raw material and the remaining 1 / 2 mass of triethylamine, the dripping time is 1 hour, and after the dripping is completed, the heat is kept for 5 hours, the triethylamine and butyl acetate are removed in vacuo, the temperature is reduced and the material is discharged to obtain a vinyl elastomer.

[0016] It is further defined that the amount of butyl acetate used is 1.2-1.25 times the mass of the epoxy resin.

[0017] It is further defined that in step 2, the molar ratio of polyetheramine, bismaleimide resin, triallyl isocyanurate and diallyl bisphenol A is 1:(0.8-0.85):(0.35-0.4):0.2.

[0018] It is further defined that the polyetheramine is composed of ED600, E300 and E100 in a molar ratio of 1:(0.6-0.65):(0.55-0.6).

[0019] To further restrict, use D2000 instead of ED600.

[0020] It is further defined that the operation process of step 2 is: dissolving polyetheramine, bismaleimide resin and triallyl isocyanurate in DMF, reacting at 115-120°C for 48 hours, then adding diallyl bisphenol A, reacting at 130°C for 30 minutes, removing DMF in vacuo, cooling and discharging the material to obtain a heat-resistant active end group toughening agent.

[0021] It is further defined that the ratio of the mass of DMF to the total mass of the polyetheramine, the BMI resin and triallyl isocyanurate is 7:3.

[0022] It is further defined that in step 3, the mass ratio of the vinyl elastomer, the heat-resistant active end group toughening agent, the active diluent, the flame retardant and the initiator is 100:(10-15):(55-60):(15-18):(5-7).

[0023] It is further defined that the reactive diluent is HDDA.

[0024] It is further defined that the flame retardant is OP935.

[0025] It is further defined that the initiator is GC-2021.

[0026] It is further defined that the mixing speed in step 3 is 3500 rad / min and the mixing time is 1 h.

[0027] The second object of the present invention is to provide a UV-curable electronic protective coating obtained by the above-mentioned preparation method, which is used for protecting electronic circuits.

[0028] It is further defined that the coating is coated on the part to be protected by a spraying process, and then irradiated with 395nm ultraviolet rays for 5-10s to obtain a protective film on the surface of the part to be protected.

[0029] Beneficial effects of the invention:

[0030] The present invention obtains a UV-curable protective coating by synthesizing two new resins of vinyl elastomer and heat-resistant active end-group toughening agent, and compounding with active diluent, accelerator, flame retardant and initiator. After curing, the coating can realize the protection function of electronic circuits, and at the same time, compared with the technical route of existing pasting covering film, it has the advantages of high construction efficiency, fast molding speed and lower energy consumption. In addition, the vinyl elastomer used in the UV-curable protective coating provided by the present invention is based on epoxy resin, increases the molecular weight by polycondensation with polyether polyol, and is end-capped with raw materials such as acrylic acid. While increasing the molecular weight, the cross-linking density can be reduced and the toughness can be improved, while suppressing the powdering at high temperature, and improving the stability of the film layer after curing. And the heat-resistant active end-group toughening agent used is obtained by Michael addition of polyetheramine and bismaleimide and other materials, which not only has good heat resistance, but also can play a significant toughening effect on the system, and improves the bending resistance of the protective film formed by UV curing of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a comparison chart of infrared spectra of the electronic protective coating prepared in Example 1 before and after curing;

[0032] Figure 2 This is a comparison chart of the TGA curves of the electronic protective coating prepared in Example 1 and the pure EA film. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0036] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained through commercial channels by those skilled in the art.

[0037] Example 1

[0038] Step 1, dissolving epoxy resin and polyether polyol in butyl acetate, adding 1 / 2 mass of triethylamine, heating to 130° C. and reflux reaction for 6 hours, then cooling to 105° C., dripping a mixture of allyl raw material and the remaining 1 / 2 mass of triethylamine, the dripping time is 1 hour, and after the dripping is completed, the temperature is kept for 5 hours, the triethylamine and butyl acetate are removed in vacuo, and the temperature is lowered to obtain a vinyl elastomer.

[0039] Among them, the molar ratio of epoxy resin, polyether polyol and allyl raw material is 1:0.3:0.65; the epoxy resin is composed of AG80, E51 and MF-2133 in a molar ratio of 1:0.3:0.65; the allyl raw material is composed of acrylic acid and methacrylic acid in a molar ratio of 1:0.5; the number average molecular weight of the polyether polyol is 1000; the catalyst is triethylamine, and the amount used is 0.3wt% of the epoxy resin.

[0040] Step 2, dissolving polyetheramine, bismaleimide resin and triallyl isocyanurate in DMF, reacting at 115-120° C. for 48 hours, then adding diallyl bisphenol A, reacting at 130° C. for 30 minutes, removing DMF in vacuo, cooling and discharging, and obtaining a heat-resistant active end group toughening agent.

[0041] The molar ratio of polyetheramine, bismaleimide resin, triallyl isocyanurate and diallyl bisphenol A is 1:0.8:0.35:0.2; the polyetheramine is composed of ED600, E300 and E100 in a molar ratio of 1:0.6:0.55.

[0042] Step 3, dissolving the vinyl elastomer and the heat-resistant active terminal toughening agent in the active diluent, adding the accelerator, the flame retardant and the initiator, mixing at room temperature in the dark, and obtaining the electronic protective coating.

[0043] Among them, the mass ratio of vinyl elastomer, heat-resistant active end-group toughening agent, active diluent, flame retardant and initiator is 100:10:55:15:5; the active diluent is HDDA; the flame retardant is OP935; and the initiator is GC-2021.

[0044] The electronic protective coating obtained in this embodiment is subjected to infrared spectrum test. Figure 1 As shown, Figure 1 EA / MBMIfilm corresponds to electronic protective coating, EA corresponds to pure EA film, modidied BMI (MBMI) corresponds to heat-resistant active end-group toughening agent, and BMI corresponds to uncured modified bismaleimide resin. Figure 1 It can be seen that due to the Michael addition reaction, the infrared spectrum of the heat-resistant active end-group toughening agent at 2926 cm -1 The stretching vibration peak of the CH bond at 3102 cm -1 The peak at 835 cm corresponds to the vibration of the CH bond on the double bond, while the peak at 835 cm -1 The peaks at 1150cm correspond to the deformation vibration of the C=C bond. These two peaks disappear in the modified BMI (MBMI), indicating that the Michael addition reaction proceeds smoothly. -1 The peak at 1635 cm is the stretching vibration of the COC bond, indicating that the ether bond in acrylic acid was successfully introduced into the BMI structure. In addition, we analyzed the infrared spectra of EA and MBMI before and after UV curing, as well as the infrared spectrum of uncured modified BMI. After the reaction, the CH=CH in EA is at 1635 cm -1 The characteristic absorption peak at 835 cm-1 disappears, indicating that the double bond is consumed. -1 The C=C double bond deformation vibration peak and the peak at 690 cm -1 The out-of-plane bending vibration peak also almost disappeared, indicating that the double bond has been converted.

[0045] The TGA curves of the electronic protective coating and pure EA film obtained in this example are as follows: Figure 2 As shown by Figure 2It can be seen that compared with pure EA film, the initial decomposition temperature of EA / MBMI film prepared by compound modification is higher. At the same time, when the temperature reaches 340℃, the thermal decomposition rate of EA is slightly faster than that of EA / MBMI.

[0046] The viscosity of the electronic protective coating obtained in this embodiment is 800 mPa·s.

[0047] The electronic protective coating obtained in this embodiment is applied to the spray coating of the flexible copper-clad laminate, with a thickness of 35 microns, cured after 395nm ultraviolet irradiation for 5 seconds, a hardness of 3H, and a cycle bending number of 12,000 times. This is mainly because the UV-cured protective coating contains rigid benzene rings, which can enhance the connectivity between molecules and improve the deformation resistance. At the same time, with the adjustment of the proportion of heat-resistant active end group toughening agent, the number of ether bonds in the resin can be increased, thereby improving the flexibility of the polymer.

[0048] The difference between this embodiment and embodiment 1 is that in step 1, the molar ratio of epoxy resin, polyether polyol and allyl raw material is 1:0.35:0.7, and the other parameter settings and process steps are the same as those in embodiment 1.

[0049] The viscosity of the electronic protective coating obtained in this embodiment is 780 mPa·s.

[0050] The electronic protective coating obtained in this embodiment is applied to the spray coating of the flexible copper-clad laminate, has a thickness of 35 microns, is cured after irradiation with 395nm ultraviolet rays for 5 seconds, has a hardness of 2H, and can be bent 11,500 times.

[0051] Example 3

[0052] The difference between this embodiment and embodiment 1 is that in step 1, the epoxy resin is composed of AG80, E51 and MF-2133 in a molar ratio of 1:0.35:0.7, and the other parameter settings and process steps are the same as those in embodiment 1.

[0053] The viscosity of the electronic protective coating obtained in this embodiment is 770 mPa·s.

[0054] The electronic protective coating obtained in this embodiment is applied to the spray coating of the flexible copper-clad laminate, has a thickness of 35 microns, is cured after irradiation with 395nm ultraviolet rays for 5 seconds, has a hardness of 2H, and can be bent 10,500 times.

[0055] Example 4

[0056] The difference between this embodiment and embodiment 1 is that in step 1, the allyl raw material is composed of acrylic acid and methacrylic acid in a molar ratio of 1:0.6, and the other parameter settings and process steps are the same as those of embodiment 1. The viscosity of the electronic protective coating obtained in this embodiment is 820 mPa·s.

[0057] The electronic protective coating obtained in this embodiment is applied to the spray coating of the flexible copper-clad laminate, has a thickness of 35 microns, is cured after irradiation with 395nm ultraviolet rays for 5 seconds, has a hardness of 3H, and can be bent 10,000 times.

[0058] Example 5

[0059] The difference between this embodiment and embodiment 1 is that in step 2, the molar ratio of polyetheramine, bismaleimide resin, triallyl isocyanurate and diallyl bisphenol A is 1:0.85:0.4:0.2, and the other parameter settings and process steps are the same as those in embodiment 1.

[0060] The viscosity of the electronic protective coating obtained in this embodiment is 710 mPa·s.

[0061] The electronic protective coating obtained in this embodiment is applied to the spray coating of the flexible copper-clad laminate, with a thickness of 55 microns, cured after 395nm ultraviolet irradiation for 5 seconds, a hardness of 4H, and a number of cyclic bending times of 10,200 times.

[0062] Example 6

[0063] The difference between this embodiment and embodiment 1 is that D2000 is used to replace ED600 in step 2, and the other parameter settings and process steps are the same as those in embodiment 1.

[0064] The viscosity of the electronic protective coating obtained in this embodiment is 710 mPa·s.

[0065] The electronic protective coating obtained in this embodiment is applied to the spray coating of the flexible copper-clad laminate, has a thickness of 35 microns, is cured after irradiation with 395nm ultraviolet rays for 5 seconds, has a hardness of 2H, and can be bent 12,000 times.

[0066] Example 7

[0067] The difference between this embodiment and embodiment 1 is that in step 2, the polyetheramine is composed of ED600, E300 and E100 in a molar ratio of 1:0.65:0.6, and the other parameter settings and process steps are the same as those in embodiment 1.

[0068] The viscosity of the electronic protective coating obtained in this embodiment is 700 mPa·s.

[0069] The electronic protective coating obtained in this embodiment is applied to the spray coating of the flexible copper-clad laminate, has a thickness of 35 microns, is cured after irradiation with 395nm ultraviolet rays for 5 seconds, has a hardness of 2H, and can be bent 10,100 times.

[0070] Example 8

[0071] The difference between this embodiment and embodiment 7 is that D2000 is used to replace ED600 in step 2, and the remaining parameter settings and process steps are the same as those in embodiment 1.

[0072] The viscosity of the electronic protective coating obtained in this embodiment is 740 mPa·s.

[0073] The electronic protective coating obtained in this embodiment is applied to the spray coating of the flexible copper-clad laminate, has a thickness of 35 microns, is cured after irradiation with 395nm ultraviolet rays for 5 seconds, has a hardness of 3H, and can be bent 10,200 times.

[0074] Example 9

[0075] The difference between this embodiment and Embodiment 7 is that in step 3, the mass ratio of vinyl elastomer, heat-resistant active end group toughening agent, active diluent, flame retardant and initiator is 100:15:60:18:7; the other parameter settings and process steps are the same as those in Embodiment 1.

[0076] The viscosity of the electronic protective coating obtained in this embodiment is 700 mPa·s.

[0077] The electronic protective coating obtained in this embodiment is applied to the spray coating of the flexible copper clad laminate, with a thickness of 45 microns, cured after 395nm ultraviolet irradiation for 5 seconds, a hardness of 4H, and a number of cyclic bending times of 10,400 times.

[0078] Although the present invention has been disclosed as above in the preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for preparing a UV-curable electronic protective coating, characterized in that: include: Step 1, using epoxy resin as raw material, polycondensing with polyether polyol under the action of a catalyst to increase the molecular weight, and then using an allyl raw material to end-cap to obtain a vinyl elastomer; In the step 1, the molar ratio of the epoxy resin, the polyether polyol and the allyl raw material is 1:(0.3-0.35):(0.65-0.7), and the amount of the catalyst is 0.3-0.35wt% of the epoxy resin; In the step 1, the epoxy resin is composed of AG80, E51 and MF2133 in a molar ratio of 1:(0.3-0.35):(0.65-0.7); the allyl raw material is composed of acrylic acid and methacrylic acid in a molar ratio of 1:(0.5-0.6); the number average molecular weight of the polyether polyol is 1000; and the catalyst is triethylamine; Step 2, using polyetheramine, bismaleimide resin, triallyl isocyanurate and diallyl bisphenol A as raw materials, and obtaining a heat-resistant active terminal toughening agent through Michael addition and polycondensation reaction; In the step 2, the molar ratio of polyetheramine, bismaleimide resin, triallyl isocyanurate and diallyl bisphenol A is 1:(0.8-0.85):(0.35-0.4):0.2; the polyetheramine is composed of ED600, E300 and E100 in a molar ratio of 1:(0.6-0.65):(0.55-0.6); Step 3, dissolving the vinyl elastomer and the heat-resistant active terminal toughening agent in an active diluent, adding an accelerator, a flame retardant and an initiator, and mixing at room temperature in the dark to obtain an electronic protective coating; In the step 3, the mass ratio of the vinyl elastomer, the heat-resistant active end group toughening agent, the active diluent, the flame retardant and the initiator is 100:(10-15):(55-60):(15-18):(5-7).

2. The preparation method according to claim 1, characterized in that: The operation process of step 1 is: dissolving the epoxy resin and the polyether polyol in butyl acetate, adding 1 / 2 mass of triethylamine, heating to 130° C. and reflux reaction for 6 hours, then cooling to 105° C., dripping the mixture of the allyl raw material and the remaining 1 / 2 mass of triethylamine, the dripping time is 1 hour, and after the dripping is completed, the temperature is kept for 5 hours, the triethylamine and butyl acetate are removed in vacuo, and the temperature is lowered to discharge the material to obtain a vinyl elastomer.

3. The preparation method according to claim 1, characterized in that: Use D2000 to replace ED600.

4. The preparation method according to claim 1, characterized in that: The operation process of step 2 is: dissolving polyetheramine, bismaleimide resin and triallyl isocyanurate in DMF, reacting at 115-120°C for 48h, then adding diallyl bisphenol A, reacting at 130°C for 30min, removing DMF in vacuo, cooling and discharging, and obtaining a heat-resistant active end group toughening agent.

5. The preparation method according to claim 1, characterized in that: The active diluent is HDDA; the flame retardant is OP935; and the initiator is GC-2021.

6. An ultraviolet curing electronic protective coating obtained by the preparation method according to any one of claims 1 to 5.

7. A method for preparing an electronic circuit protective film, characterized in that: The method of spraying the The UV-curable electronic protective coating is applied to the electronic circuit to be protected, and then irradiated with 395nm ultraviolet light for 5-10s. An electronic circuit protection film is obtained on the surface of the electronic circuit to be protected.

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