Uv-cured three-protection paint and its spray curing process

Abstract

The present disclosure provides a kind of UV curing three-proof paint, including the mass fraction of each component as follows: glycidyl ether epoxy resin 40-50 parts;Active epoxy diluent 30-50 parts;Photoinitiator 0.1-5 parts;Delayed curing agent 0.01-10 parts;Auxiliary agent 1.21-12 parts.Because glycidyl ether epoxy resin contains ether bond and ether bond is polar group, it helps to improve the wettability and adhesion of glycidyl ether epoxy resin, effectively improves the adhesion of UV curing three-proof paint after curing, and the active epoxy diluent can improve the toughness of UV curing three-proof paint after curing, thereby effectively improving the stability of UV curing three-proof paint, and effectively improving the protection performance of UV curing three-proof paint.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of UV three-proof paint, in particular to a new type of UV curing three-proof paint and its curing process. BACKGROUND

[0002] The environment in which the circuit board is placed in actual work is complex and changeable, and it may face humidity, high heat, salt spray, low temperature, vibration and high dust. If there is no corresponding effective protection, the circuit board will soon corrode, deform, mildew and age, and finally cause circuit failure and equipment failure.

[0003] In order to reduce the damage of the external environment to the circuit board and ensure the normal work of the equipment, protective paint, also known as UV light wet curing three-proof paint, is often sprayed on the circuit board. The chemical components of the protective paint are mainly acrylate, silicone and polyurethane, epoxy resin, etc. Their working principle is to form a protective film on the surface of the circuit board, so that it will not be damaged due to the influence of the working environment, thereby increasing the quality reliability of the circuit board. However, the current UV light wet curing three-proof paint cannot meet the test requirements of the existing new energy field, especially the three-proof paint for PCB circuit. The current three-proof paint for PCB circuit has the problems of over-thick paint film leading to insufficient curing during pre-construction and post-processing, poor flowability leading to uneven coating, and inability to be applied in non-light-transmitting use scenarios, etc. This makes the dustproof, moisture-proof and salt spray-proof properties of the three-proof paint decline, and the service life of the circuit board is reduced too quickly.

[0004] For example, Chinese patent document CN116676063A discloses a UV adhesive with controllable curing time, which comprises the following raw materials by weight: alicyclic epoxy resin 50-100 parts and photoinitiator 0.11-4 parts; wherein the photoinitiator includes cationic photoinitiator and imidazole type accelerator; the mass of the imidazole type accelerator accounts for 0.95%-90% of the mass of the photoinitiator. The introduction of the imidazole type accelerator delays the UV curing rate of the cationic photoinitiator. The combination of the two can achieve the effect of prolonging the curing time, i.e., the resin can continue to cure relatively slowly even without light irradiation after preliminary curing by light. Moreover, by controlling the content of the imidazole type accelerator, the UV curing time of the adhesive can be further adjusted to achieve delayed curing at different times, and the operation time can be accurately controlled during production and application.

[0005] However, the above-mentioned UV adhesive with controllable curing time has the following problems:

[0006] Although the above-mentioned UV adhesive with controllable curing time can continue to complete the curing relatively slowly even in the absence of light after preliminary curing by light, to adapt to the application of light-proof scenes, due to the ester bond contained in the alicyclic epoxy resin, the ester bond is prone to decomposition due to poor aging resistance and strong water absorption, thereby causing poor adhesion and poor protection performance of the UV adhesive. SUMMARY

[0007] The purpose of the present disclosure is to overcome the shortcomings in the prior art and provide a new UV-cured three-protection paint with good adhesion and good protection performance and a spraying and curing process thereof.

[0008] The purpose of the present disclosure is achieved by the following technical solutions:

[0009] A new UV-cured three-protection paint comprises the following components in mass fraction:

[0010] glycidyl ether epoxy resin 40-50 parts;

[0011] active epoxy diluent 30-50 parts;

[0012] photoinitiator 0.1-5 parts;

[0013] delayed curing agent 0.01-10 parts;

[0014] auxiliary agent 1.21-12 parts;

[0015] The chemical formula structure of the delayed curing agent is

[0016]

[0017] The reaction equation of the delayed mechanism of the delayed curing agent is

[0018]

[0019] R1 is an isocyanate compound, and R2 is the glycidyl ether epoxy resin.

[0020] In one embodiment, the glycidyl ether epoxy resin is at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin and hydrogenated bisphenol A epoxy resin.

[0021] In one embodiment, the active epoxy diluent is one or more of oxetane diluent, glycidyl ether diluent and vinyl ether diluent.

[0022] In one embodiment, the photoinitiator is an onium salt compound.

[0023] ​​In one of the embodiments, the additive package is a mixture of one or more of defoaming agent, leveling agent, coupling agent, and fluorescent identification agent.

[0024] In one of the embodiments, the defoaming agent is a combination of one or more of silicone-based defoaming agent, oil-based defoaming agent, and amide-based defoaming agent.

[0025] In one of the embodiments, the leveling agent is a combination of one or more of silicone-based leveling agent, fluorine-modified leveling agent, and acrylic-based leveling agent.

[0026] In one of the embodiments, the coupling agent is at least one of gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, (3- glycidoxypropylpropoxy)trimethoxysilane, (3-glycidoxypropylpropoxy)triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 2-(3,4- epoxycyclohexyl)ethyltriethoxysilane.

[0027] In one of the embodiments, the fluorescent identification agent is 9,10-dibutoxyanthracene.

[0028] A spraying and curing process of the novel UV-cured conformal coating, which is used to spray the novel UV-cured conformal coating of any one of the above embodiments on a circuit board, so that the novel UV-cured conformal coating is cured on the circuit board to form a protective coating film.

[0029] The spraying and curing process of the novel UV-cured conformal coating comprises the following steps:

[0030] Preparation of the novel UV-cured conformal coating slurry;

[0031] Pre-curing treatment of the novel UV-cured conformal coating slurry;

[0032] Spraying operation of the pre-cured novel UV-cured conformal coating slurry, so that the novel UV-cured conformal coating is sprayed on the circuit board;

[0033] Strong light curing operation of the circuit board, so that the surface of the circuit board is divided into a UV irradiation blind area and a UV irradiation coverage area;

[0034] Static curing operation of the circuit board after strong light curing, so that the novel UV-cured conformal coating in the UV irradiation blind area is cured.

[0035] Compared with the prior art, the present disclosure has at least the following advantages:

[0036] 1. Since glycidyl ether epoxy resins contain ether bonds and the ether bonds are polar groups, they help improve the wettability and adhesion of glycidyl ether epoxy resins, effectively enhancing the adhesion of the new UV-cured conformal coating after curing. At the same time, the active epoxy diluent can improve the toughness of the cured new UV-cured conformal coating, thereby effectively improving the stability of the new UV-cured conformal coating and thus effectively improving the protective performance of the new UV-cured conformal coating.

[0037] 2. During the curing process of the new UV-curable conformal coating, the photoinitiator generates super acid. The delayed curing agent, which is composed of isocyanate-based compounds and glycidyl ether epoxy resin, can absorb the super acid. After being heated or left at room temperature for a period of time, the delayed curing agent releases the super acid to promote the ring-opening curing of the glycidyl ether epoxy resin. The absorption and release of super acid by the delayed curing agent is a reversible dynamic equilibrium process, which enables the delayed curing effect of the new UV-curable conformal coating. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a flowchart of the spraying and curing process of a novel UV-curable conformal coating in one embodiment;

[0040] Figure 2 for Figure 1 The diagram shows a flow chart of the spraying and curing process for the novel UV-curable conformal coating.

[0041] Figure 3 This is a graph showing the change in the content of delayed curing agent versus the complete curing time.

[0042] Figure 4 This is a graph showing the relationship between the content of delayed curing agent and the viscosity of the pre-cured slurry. Detailed Implementation

[0043] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0044] It should be noted that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. Where an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements can also be present. The terms "vertical", "horizontal", "left", "right" and similar expressions as used herein are for illustrative purposes only and are not intended to be limiting.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used in the description of the disclosure herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0046] The novel UV curing three-proofing paint provided by the present disclosure comprises the following components by mass fraction:

[0047] Glycidyl ether epoxy resin 40-50 parts;

[0048] Active epoxy diluent 30-50 parts;

[0049] Photoinitiator 0.1-5 parts;

[0050] Delayed curing agent 0.01-10 parts;

[0051] Auxiliary agent 1.21-12 parts;

[0052] The chemical formula of the delayed curing agent is

[0053] ;

[0054] The delayed reaction equation of the delayed curing agent is

[0055] ;

[0056] R1 is an isocyanate compound, and R2 is the glycidyl ether epoxy resin.

[0057] The novel UV curing three-proofing paint described above, because the glycidyl ether epoxy resin contains ether bonds and the ether bonds are polar groups, helps to improve the wettability and adhesion of the glycidyl ether epoxy resin, effectively improves the adhesion of the novel UV curing three-proofing paint after curing, and the active epoxy diluent can improve the toughness of the novel UV curing three-proofing paint after curing, thereby effectively improving the stability of the novel UV curing three-proofing paint, and further effectively improving the protective performance of the novel UV curing three-proofing paint.

[0058] Further, when the new UV-curable three-protection paint is cured, the photo initiator generates super acid, and the delayed curing agent generated from the isocyanate compound and glycidyl ether epoxy resin can absorb the super acid. Then, after a period of time by heating or at room temperature, the delayed curing agent releases the super acid, so as to promote the ring-opening curing of the glycidyl ether epoxy resin. The absorption and release of the super acid by the delayed curing agent is a reversible dynamic equilibrium process, so as to achieve the delayed curing effect of the new UV-curable three-protection paint.

[0059] It should be noted that the lower the content of the delayed curing agent, the faster the ring-opening curing speed of the epoxy resin. Therefore, in the present embodiment, the mass fraction of the delayed curing agent is between 0.01 parts and 10 parts, i.e. the curing speed of the epoxy resin can be regulated by controlling the content of the delayed curing agent, so as to achieve the effect that the delay time of the epoxy resin is controllable. Further, the delayed curing agent contains the component of glycidyl ether epoxy resin, so that the delayed curing agent and the glycidyl ether epoxy resin in the system form a single component. Thus, the mixing time of the new UV-curable three-protection paint can be reduced, thereby effectively improving the production efficiency of the new UV-curable three-protection paint.

[0060] It should be further noted that the photo initiator is a cationic initiator. Under the irradiation of ultraviolet light, the molecules in the photo initiator are activated into an excited state, and the molecules decompose to generate super protonic acid, i.e. super acid.

[0061] It should be further noted that the delayed curing agent is synthesized by putting R1 and R2 into a reactor and heating at 70-80°C for 3-4h. A catalyst is also added, which is organotin dilaurylate.

[0062] In one embodiment, the glycidyl ether epoxy resin is at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin and hydrogenated bisphenol A epoxy resin. It can be understood that the bisphenol A type epoxy resin, bisphenol F type epoxy resin and hydrogenated bisphenol A epoxy resin are all glycidyl ether epoxy resins, and the ether bond in the glycidyl ether epoxy resin is a polar group, which can help to improve the wettability and adhesion, so that the new UV-curable three-protection paint has good adhesion. At the same time, the glycidyl ether epoxy resin also has good self-protection performance, which is manifested in good resistance to high temperature and humidity, high and low temperature cycle, moisture, acid and alkali, smoke and corrosive gas. In this way, the new UV-curable three-protection paint is not easy to fall off when it is sprayed and cured on the circuit board, and can provide good protection effect for the circuit board, thereby reducing the damage of the external environment to the circuit board, and effectively prolonging the service life of the circuit board.

[0063] In one embodiment, the reactive epoxy diluent is one or more of an oxetane diluent, a glycidyl ether diluent, and a vinyl ether diluent.

[0064] In one embodiment, the oxetane monomer in the oxetane diluent is one or more of a combination of 3-ethyl-3-hydroxymethyl oxetane, 3-ethyl-3-[(2-ethylhexyloxy)methyl]oxetane, 3,3'-(oxybis(methylene)bis(3-ethyl)oxetane, and 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene.

[0065] In one embodiment, the reactive epoxy diluent is preferably a 3-ethyl-3-hydroxymethyl oxetane diluent. It can be understood that the 3-ethyl-3-hydroxymethyl oxetane monomer is a reactive monomer, which has a reactive group that can effectively improve the bonding strength of the new UV-curable conformal coating. Moreover, the 3-ethyl-3-hydroxymethyl oxetane monomer has a low viscosity, so that when it is used as a reactive epoxy diluent, the viscosity range of the new UV-curable conformal coating is wider, which can adapt to more application scenarios. Further, since the added amount of the reactive epoxy diluent is 30 parts to 50 parts, and the reactive epoxy diluent is a 3-ethyl-3-hydroxymethyl oxetane monomer diluent, the viscosity of the new UV-curable conformal coating is moderate, which promotes the full progress of the curing reaction. At the same time, the above-mentioned amount of 3-ethyl-3-hydroxymethyl oxetane can improve the bonding strength and mechanical strength of the new UV-curable conformal coating while ensuring the delay of curing of the new UV-curable conformal coating.

[0066] In one of the embodiments, the glycidyl ether monomer in the glycidyl ether diluent is one or a combination of ortho-cresyl glycidyl ether, isopropyl glycidyl ether, octyl glycidyl ether, allyl glycidyl ether, butyl glycidyl ether, glycidyl methacrylate, t-butyl glycidyl ether, 1,4-butanediol glycidyl ether, 1,4-butanediol diglycidyl ether, p-t-butylphenyl glycidyl ether, decyl glycidyl ether, methoxy polyethylene glycol glycidyl ether, carbon dodecyl to tridecyl glycidyl ether, carbon octyl to decyl glycidyl ether, carbon dodecyl glycidyl ether, carbon dodecyl to tetradecyl glycidyl ether, octyl glycidyl ether, benzyl glycidyl ether, ortho-cresyl glycidyl ether, phenyl glycidyl ether, butyl glycidyl ether, cardanol glycidyl ether, allyl polyether glycidyl ether, polypropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,2-cyclohexanediol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, dipropylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, ethylene glycol diglycidyl ether, and flexible bisphenol A glycidyl ether.

[0067] In one of the embodiments, the vinyl ether monomer in the vinyl ether diluent is one or a combination of vinyl methyl ether, vinyl ethyl ether, vinyl n-propyl ether, vinyl isopropyl ether, vinyl t-butyl ether, vinyl n-butyl ether, vinyl isobutyl ether, vinyl cyclohexyl ether, vinyl ethylene glycol ether, vinyl diethylene glycol ether, 4-hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, and ethylene glycol monoallyl ether.

[0068] In one of the embodiments, the photoinitiator is an onium salt compound. It can be understood that the onium salt compound has good compatibility with the delayed curing agent, and the onium salt compound as the photoinitiator has good stability, so that the novel UV-curable conformal coating can realize accurate regulation of the UV curing time of the novel UV-curable conformal coating by regulating the content of the delayed curing agent, so that the curing can be completed within the time without affecting the production efficiency.

[0069] In one of the embodiments, the onium salt compound is one or a combination of diaryliodonium salt, triaryliodonium salt, alkyl iodonium salt, and isopropyl phenyl iron hexafluorophosphate. It can be understood that the diaryliodonium salt, triaryliodonium salt, alkyl iodonium salt, and isopropyl phenyl iron hexafluorophosphate are all cationic photoinitiators, and all can produce super acid under ultraviolet light irradiation.

[0070] In one embodiment, the additive package is a mixture of one or more of defoaming agent, leveling agent, coupling agent, and fluorescent identification agent.

[0071] In one embodiment, the defoaming agent is a combination of one or more of silicone-based defoaming agent, oil-based defoaming agent, and amide-based defoaming agent.

[0072] In one embodiment, the leveling agent is a combination of one or more of silicone-based leveling agent, fluorine-modified leveling agent, and acrylic-based leveling agent.

[0073] In one embodiment, the coupling agent is at least one of γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, (3-glycidoxypropoxy)trimethoxysilane, (3-glycidoxypropoxy)triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

[0074] In one embodiment, the fluorescent identification agent is 9,10-dibutoxyanthracene.

[0075] Referring to Figure 1 The present disclosure also provides a novel UV-cured three-protection paint spraying and curing process for spraying the novel UV-cured three-protection paint on a circuit board to form a protective paint film on the circuit board.

[0076] The novel UV-cured three-protection paint spraying and curing process of one embodiment includes the following steps:

[0077] S100, preparing a novel UV-cured three-protection paint slurry.

[0078] In this embodiment, the components of the novel UV-cured three-protection paint are mixed in a reaction tank according to the mass fraction ratio to obtain a novel UV-cured three-protection paint slurry.

[0079] S200, performing a pre-curing treatment on the novel UV-cured three-protection paint slurry.

[0080] In this embodiment, the novel UV-cured three-protection paint slurry is irradiated with weak ultraviolet light to activate the novel UV-cured three-protection paint slurry, so that the photoinitiator generates superacid, and the delayed curing agent absorbs the superacid, thereby activating the activity of the delayed curing agent, and achieving the delayed curing effect of the novel UV-cured three-protection paint.

[0081] S300, performing a spraying operation on the pre-cured novel UV-cured three-protection paint slurry to spray the novel UV-cured three-protection paint on a circuit board.

[0082] In the embodiment, the new UV-cured three-protection paint slurry after pre-curing is sprayed on the circuit board, so that the new UV-cured three-protection paint can cover on the circuit board, to facilitate subsequent curing to form a protective paint film.

[0083] S400, the strong light curing operation is performed on the circuit board, so that the surface of the circuit board is divided into a UV irradiation blind area and a UV irradiation coverage area.

[0084] In the embodiment, due to the presence of many components on the circuit board, the strong ultraviolet light cannot completely cover the circuit board, so that the surface of the circuit board is divided into a UV irradiation blind area and a UV irradiation coverage area. Under the irradiation of strong ultraviolet light, the new UV-cured three-protection paint in the UV irradiation coverage area can accelerate curing to form a protective paint film, while the new UV-cured three-protection paint in the UV irradiation blind area has been activated by the delayed curing agent, which can be completely cured by heating or standing for a period of time, so as to ensure that the UV-cured three-protection paint on the circuit board is completely cured.

[0085] S500, the strong light curing operation is performed on the circuit board, so that the surface of the circuit board is divided into a UV irradiation blind area and a UV irradiation coverage area.

[0086] In the embodiment, due to the presence of many components on the circuit board, the strong ultraviolet light cannot completely cover the circuit board, so that the surface of the circuit board is divided into a UV irradiation blind area and a UV irradiation coverage area. Under the irradiation of strong ultraviolet light, the new UV-cured three-protection paint in the UV irradiation coverage area can accelerate curing to form a protective paint film, while the new UV-cured three-protection paint in the UV irradiation blind area has been activated by the delayed curing agent, which can be completely cured by heating or standing for a period of time, so as to ensure that the UV-cured three-protection paint on the circuit board is completely cured.

[0087] Further, in one of the embodiments, the standing curing time is 24h-48h. It can be understood that placing the strong light cured circuit board in a dark environment for 24h-48h can completely cure the new UV-cured three-protection paint on the circuit board, thereby effectively improving the adhesion of the new UV-cured three-protection paint, and further effectively improving the protection performance of the new UV-cured three-protection paint, and further prolonging the service life of the circuit board.

[0088] In one of the embodiments, the specific operation steps of the pre-curing treatment of the new UV-cured three-protection paint slurry are as follows:

[0089] First, the new UV-cured three-protection paint slurry in the reaction tank is transferred to the light transmission conveying pipeline of the activation device;

[0090] Then, weak ultraviolet light rays output by the low-power nano UV lamp are irradiated in the light-transmitting conveying pipeline to activate the novel UV-cured three-protection paint in the light-transmitting conveying pipeline.

[0091] It should be noted that the weak ultraviolet light rays output by the low-power nano UV lamp can generate super strong acid from the photoinitiator, and the super strong acid is absorbed by the delayed curing agent to activate the activity of the delayed curing agent, so that the novel UV-cured three-protection paint can be completely cured on the circuit board subsequently. Further, under the action of the weak ultraviolet light rays, the delayed curing agent is activated without affecting the physical properties (such as viscosity) of the novel UV-cured three-protection paint slurry, so that the situation of high viscosity and difficult spraying does not occur, and the subsequent spraying operation can be carried out normally.

[0092] Further, the nano value of the low-power nano UV lamp is 365 nm.

[0093] Further, in one embodiment, the light-transmitting conveying pipeline is a spiral light-transmitting conveying pipeline. It can be understood that the spiral light-transmitting conveying pipeline can irradiate the novel UV-cured three-protection paint slurry in the pipeline with weak ultraviolet light rays to ensure that the delayed curing agent in the novel UV-cured three-protection paint is completely activated, so that the novel UV-cured three-protection paint forming a UV blind area on the circuit board subsequently can be cured.

[0094] Further, in one embodiment, the energy of the weak ultraviolet light rays is 300 mj / cm 2 -500 mj / cm 2 . It can be understood that the energy of the weak ultraviolet light rays is between 300 mj / cm 2 -500 mj / cm 2 , which can activate the delayed curing agent and absorb the super strong acid of the photoinitiator, avoiding the situation of high viscosity caused by the premature curing of the novel UV-cured three-protection paint slurry.

[0095] In one embodiment, the specific operation steps of spraying the novel UV-cured three-protection paint slurry after pre-curing are as follows:

[0096] First, the novel UV-cured three-protection paint in the light-transmitting conveying pipeline is conveyed to the dispensing device;

[0097] Then, the novel UV-cured three-protection paint is sprayed on the circuit board by the dispensing gun of the dispensing device.

[0098] It should be noted that the light-tight pipeline communicated between the reaction tank and the activation device is provided with a material pumping pump, and the light-transmitting pipeline is respectively communicated with the light-tight pipeline and the glue dispensing device, that is, the new UV curing three-proof paint slurry can be conveyed from the light-transmitting pipeline to the glue dispensing device by the material pumping pump, and then the new UV curing three-proof paint slurry can be sprayed on the surface of the circuit board by the glue dispensing gun.

[0099] It should be noted that the pipeline communicated between the light-transmitting pipeline and the glue dispensing device is also a light-tight pipeline.

[0100] Further, since the content of the delayed curing agent will affect the viscosity of the new UV curing three-proof paint, it is difficult to spray the new UV curing three-proof paint slurry when the viscosity of the new UV curing three-proof paint is too large. Therefore, the mass fraction of the delayed curing agent is controlled between 0.01 parts and 10 parts, that is, the viscosity of the new UV curing three-proof paint slurry can be controlled by adjusting the content of the delayed curing agent, so as to avoid the difficulty of spraying the new UV curing three-proof paint slurry when the viscosity of the new UV curing three-proof paint is too large, thereby ensuring that the new UV curing three-proof paint has good spraying effect and the surface of the circuit board can be covered by the new UV curing three-proof paint.

[0101] Further, in one embodiment, the mass fraction of the delayed curing agent is preferably 0.1 parts to 1 part.

[0102] In one embodiment, the specific operation steps of the strong light curing operation on the circuit board are as follows:

[0103] The high-power nano UV lamp outputs strong ultraviolet light to irradiate on the circuit board, so that the surface of the circuit board is divided into the UV irradiation blind area and the UV irradiation coverage area.

[0104] It should be noted that under the irradiation of strong ultraviolet light, the new UV curing three-proof paint in the UV irradiation coverage area can accelerate curing, so that a protective paint film is formed on the surface of the circuit board. The new UV curing three-proof paint in the UV irradiation blind area releases super strong acid after a period of time, which promotes the ring-opening curing of the epoxy resin in the UV irradiation blind area, so that the new UV curing three-proof paint on the circuit board is completely cured, thereby effectively improving the adhesion of the new UV curing three-proof paint, and effectively prolonging the service life of the circuit board.

[0105] Further, the nano value of the high-power nano UV lamp is 365 nm.

[0106] The following examples are given, but it should be noted that the following examples do not exhaust all possible cases, and the materials used in the following examples are commercially available unless otherwise specified.

[0107] Table 1

[0108]

[0109] Example 1

[0110] The UV-curable three-protection paint is prepared according to the material ratio table in Table 1. After all the raw materials are uniformly mixed, centrifugal defoaming is performed, and the UV-curable three-protection paint is obtained.

[0111] The epoxy resin is a bisphenol A type epoxy resin.

[0112] The epoxy diluent is 3-ethyl-3-oxabutyl alcohol monomer.

[0113] The photoinitiator is a triaryl iodonium salt.

[0114] The coupling agent is gamma-glycidyl ether oxypropyl trimethoxysilane, model KH560.

[0115] The leveling agent is an organic silicon leveling agent, model BYK333.

[0116] The defoaming agent is an organic silicon defoaming agent, model BYK067.

[0117] The fluorescent recognition agent is 9,10-dibutoxy anthracene, model TR-PSS-303 from Changzhou Qiangli Electronic New Material Co., Ltd.

[0118] Example 2

[0119] The difference from Example 1 is that the mass fraction of the delayed curing agent is 0.05.

[0120] Example 3

[0121] The difference from Example 1 is that the mass fraction of the delayed curing agent is 0.1.

[0122] Example 4

[0123] The difference from Example 1 is that the mass fraction of the delayed curing agent is 0.5.

[0124] Example 5

[0125] The difference from Example 1 is that the mass fraction of the delayed curing agent is 1.

[0126] Example 6

[0127] The difference from Example 1 is that the mass fraction of the delayed curing agent is 0.05.

[0128] Comparative Example 1

[0129] The difference from Example 1 is that the mass fraction of the delayed curing agent is 0.

[0130] Comparative Example 2

[0131] The difference from Example 1 is that the mass fraction of the delayed curing agent is 0.001.

[0132] Comparative Example 3

[0133] The difference from Example 1 is that the epoxy resin is replaced by 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylmethyl carboxylate, and the mass fraction of the delayed curing agent is 0.5.

[0134] The spraying curing process of the new UV curing three-protection paint of the present disclosure is used to spray Examples 1-6 and Comparative Examples 1-3 on the circuit board, and the test experiments are carried out during the spraying process, the test indexes and standards are shown in Table 2, and the test results are shown in Table 3.

[0135] Table 2

[0136]

[0137] Table 3

[0138]

[0139] According to Table 3, the content of the delayed curing agent and the change curve of the complete curing time are obtained Figure 3 , and the content of the delayed curing agent and the change curve of the viscosity of the slurry after pre-curing Figure 4 .

[0140] Please refer to Table 1, Table 2 and Table 3, and compare the performance test results of Example 4 and Comparative Example 3. It can be known that under the same conditions of other materials and operations for preparing the three-protection paint, the epoxy resin used in Comparative Example 3 is 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylmethyl carboxylate, and the obtained UV curing three-protection paint has a faster curing speed, but the adhesion and protection performance of the UV curing three-protection paint are poor. The epoxy resin used in Example 4 is bisphenol A type epoxy resin, and the obtained UV curing three-protection paint has a slower curing speed than the UV curing three-protection paint of Comparative Example 3, but the adhesion and protection performance of the UV curing three-protection paint are better.

[0141] The performance test results of Examples 1-6 and Comparative Examples 1-2 are compared. It can be known that when the mass fraction of the delayed curing agent increases, firstly, the complete curing time gradually becomes longer; secondly, the viscosity gradually becomes lower, and the reduction speed gradually remains stable. When the mass fraction is 0.001, the viscosity is reduced to 0.5 after 300mj / cm 2 -500mj / cm 2After energy pre-curing, the viscosity is too large, it is difficult to spray, and it cannot play a role in delaying curing. When the mass fraction is 10, the test results show that the viscosity does not change much, it cannot be table dry for a long time and cannot be completely cured. That is, when the amount of delay curing agent is low, the delay curing agent can only absorb a small amount of super strong acid, resulting in fast curing speed of the epoxy resin. When the amount of delay curing agent gradually increases, the delay curing agent will absorb more super strong acid, resulting in gradually slower curing speed of the epoxy resin. However, when the amount of delay curing agent is too high, it will absorb most of the super strong acid, resulting in long time curing of the epoxy resin. This shows that the mass fraction of the delay curing agent is preferably 0.1 parts to 1 part, under which the viscosity is not high, the spraying fluidity is good, and the role of delaying curing can be achieved.

[0142] In combination Figure 3 and Figure 4 It can be seen that when the materials and operating conditions for preparing the UV curing three-proof paint remain unchanged, the spraying viscosity of the UV curing three-proof paint gradually decreases and the complete curing time correspondingly increases with the gradual increase of the content of the delay curing agent. This shows that by adding the delay curing agent, the new UV three-proof paint can realize the delay of the curing process, thereby achieving the effect of delaying curing.

[0143] In summary, the new UV curing three-proof paint of the present disclosure has high adhesion and high protection performance. The spraying and curing process of the new UV curing three-proof paint of the present disclosure is used for spraying and curing the circuit board, so that the new UV curing three-proof paint sprayed on the surface of the circuit board can be completely cured, thereby greatly prolonging the service life of the circuit board. Further, by adjusting the content of the delay curing agent, the viscosity and complete curing time of the new UV curing three-proof paint can be controlled, thereby ensuring good spraying effect and achieving the effect of adjustable curing time.

[0144] Compared with the prior art, the present disclosure has at least the following advantages:

[0145] 1. Since the glycidyl ether epoxy resin contains ether bonds and the ether bond is a polar group, it helps to improve the wettability and adhesion of the glycidyl ether epoxy resin, effectively improves the adhesion of the new UV curing three-proof paint after curing, and the active epoxy diluent can improve the toughness of the new UV curing three-proof paint after curing, thereby effectively improving the stability of the new UV curing three-proof paint, and further effectively improving the protection performance of the new UV curing three-proof paint.

[0146] 2, The light initiator generates super acid when the new UV curing three -proof paint is cured, the delayed curing agent generated by the isocyanate compound and glycidyl ether epoxy resin can absorb the super acid, then the delayed curing agent releases the super acid after heating or room temperature for a period of time, to promote the ring opening curing of glycidyl ether epoxy resin, and the absorption and release of super acid by the delayed curing agent is a reversible dynamic balance process, so as to realize the delayed curing effect of the new UV curing three -proof paint.

[0147] The above-described embodiments only express several embodiments of the present disclosure, which are described in detail and specifically, but cannot be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present disclosure, which are within the scope of protection of the present disclosure. Therefore, the protection scope of the present disclosure patent should be subject to the appended claims.

Claims

1. A UV-cured three-protective paint, characterized by, Comprise the following components by mass fraction: The chemical formula of the delayed curing agent is The delayed reaction equation of the delayed curing agent is R1 is an isocyanate compound, and R2 is the glycidyl ether epoxy resin.

2. The UV-cured paint according to claim 1, wherein The glycidyl ether epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and hydrogenated bisphenol A epoxy resin.

3. The UV-cured paint according to claim 1, wherein The active epoxy diluent is one or more of oxetane diluent, glycidyl ether diluent, and vinyl ether diluent.

4. The UV-cured paint according to claim 1, wherein The photoinitiator is an onium salt compound.

5. The UV-cured paint according to claim 1, wherein The auxiliary agent is a mixture of one or more of defoaming agent, leveling agent, coupling agent, and fluorescent recognition agent.

6. The UV-cured paint according to claim 5, wherein The defoaming agent is a combination of one or more of silicone defoaming agent, oil defoaming agent, and amide defoaming agent.

7. The UV-cured paint according to claim 5, wherein The leveling agent is a combination of one or more of silicone leveling agent, fluorine-modified leveling agent, and acrylic leveling agent.

8. The UV-cured paint according to claim 5, wherein The coupling agent is at least one of γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, (3-epoxypropylpropoxy) trimethoxysilane, (3-epoxypropylpropoxy) triethoxysilane, 2-(3,4-epoxycyclohexyl) ethyl trimethoxysilane, and 2-(3,4-epoxycyclohexyl) ethyl triethoxysilane.

9. The UV-cured paint according to claim 5, wherein The fluorescent recognition agent is 9,10-dibutoxyanthracene.

10. A spray curing process for UV-cured conformal coating, characterized by, The UV-curable three-protection paint is sprayed on the circuit board to form a protective paint film on the circuit board. The spraying and curing process of the UV-curable three-protection paint comprises the following steps: Preparation of UV-curable three-protection paint slurry; Pre-curing treatment of the UV-curable three-protection paint slurry; Spraying operation of the pre-cured UV-curable three-protection paint slurry to spray the UV-curable three-protection paint on the circuit board; Strong light curing operation on the circuit board to divide the surface of the circuit board into a UV irradiation blind area and a UV irradiation coverage area; Static curing operation on the circuit board after strong light curing to cure the UV-curable three-protection paint in the UV irradiation blind area.

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