A one-component light-heat dual-curing epoxy resin three-proof coating

Abstract

A single-component, light-heat dual-curing epoxy resin conformal coating. The raw materials, calculated by weight, include: 100 parts of an acrylic / silicone dual-modified epoxy resin; 8-25 parts of a diluent; 6-18 parts of an epoxy curing agent; and 1-6 parts of a photoinitiator. The diluent is an acrylic glycidyl ether compound; and the photoinitiator is an epoxy alkyl anthracene ether compound. This conformal coating exhibits excellent adhesion to printed circuit boards (PCBs), rapid photoinitiated curing, and high toughness. It also avoids the molecular migration of the photoinitiator in the coating, significantly improving the weather resistance of the conformal coating.

Description

Technical Field

[0001] The present invention relates to an epoxy resin coating, in particular to a one-component epoxy resin three-proof coating. Background Art

[0002] Conformal coatings—moisture-proof, salt spray-proof, and mildew-proof—play a vital role in the modern electronics industry. They are primarily applied to printed circuit boards (PCBs) with soldered components, forming a protective layer to improve the reliability and service life of electronic products and ensure safety. Traditional conformal coatings include acrylic, polyurethane, and silicone, but they suffer from poor adhesion, temperature resistance, weather resistance, and curing speed.

[0003] UV-curable conformal coatings are circuit board coatings that cure via the dual action of ultraviolet light and moisture. Due to their rapid curing, high hardness, strong durability, and environmentally friendly properties, they are widely used for the three-component protection of electronic circuit boards. However, in practice, UV-curable conformal coatings are not well compatible with photoinitiator systems, which can easily cause small molecule migration. This reduces the coating's adhesion to the substrate, significantly impacting the coating's reliability and potentially shortening the lifespan of electronic products. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a single-component light-heat dual-curing epoxy resin three-proof coating that can be quickly cured and has strong adhesion.

[0005] The technical solution adopted by the present invention to solve the technical problem is as follows: a one-component light-heat dual-curing epoxy resin three-proof coating, the raw materials of which include, by weight: 100 parts of acrylic acid / organic silicon dual-modified epoxy resin, 8-25 parts of diluent, 6-18 parts of epoxy curing agent, and 1-6 parts of photoinitiator;

[0006] The acrylic acid / organic silicon double-modified epoxy resin is obtained by reacting an organic alkoxy polysiloxane and an acrylic monomer compound with a multifunctional epoxy resin respectively;

[0007] The diluent is a glycidyl ether of acrylic acid compound;

[0008] The photoinitiator is an epoxyalkyl anthracene ether compound, and its chemical structure is:

[0009] ;

[0010] Among them, R 1 represents hydrogen, ethyl or chlorine, R 2 represents a C2~C6 alkylene group, R 3 represents hydrogen, methyl or ethyl.

[0011] Preferably, the weight ratio of the organoalkoxy polysiloxane, the acrylic monomer compound, and the multifunctional epoxy resin is 15-40:5-35:100.

[0012] More preferably, the multifunctional epoxy resin is a multifunctional glycidylamine resin.

[0013] More preferably, the multifunctional epoxy resin is one or a combination of two or more of bisphenol A glycidyl ether, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether methane, triglycidyl-p-aminophenol, triglycidyl triisocyanate, tetraglycidyl diaminodiphenylmethane, tetraglycidyl xylenediamine, tetraglycidyl-1,3-bisaminomethylcyclohexylamine and their homologues and derivatives.

[0014] More preferably, the active group of the organoalkoxypolysiloxane is: -SiR n (OR ， ) 3-n , where R represents H, Me, Et, Bu, Ph, Pr, C6H4CH2, C8H 17 、C 12 H 25 One of the ， It represents one of H, Me, Et, and Bu.

[0015] More preferably, the acrylic monomer is one or a combination of two or more of acrylic acid, methacrylic acid, acrylic anhydride, and acetic acrylic anhydride.

[0016] Preferably, the preparation method of the acrylic acid / silicone dual-modified epoxy resin comprises:

[0017] (1) A multifunctional epoxy resin and an organic alkoxy polysiloxane undergo dealcoholization reaction in a solvent under catalytic conditions to obtain a uniform liquid;

[0018] (2) The obtained uniform liquid is mixed with an acrylic acid monomer compound, reacted under catalytic conditions, and the solvent is removed to obtain the product.

[0019] More preferably, in the preparation method of acrylic acid / organic silicone dual-modified epoxy resin, the catalyst in step (1) is one or a combination of two or more of sodium ethoxide, potassium ethoxide, hydrochloric acid, acetic acid, AlCl3, TiCl3, SnCl3, ZrCl4, BF3, and ZnCl2.

[0020] More preferably, in the preparation method of acrylic acid / organic silicone dual-modified epoxy resin, the catalyst in step (2) is one or a combination of two or more of N,N-dimethylaniline, N,N-dimethylbenzylamine, trimethylbenzylammonium chloride, tetraethylammonium bromide, triphenylphosphine, triphenylantimony, and chromium acetylacetonate.

[0021] More preferably, in the preparation method of the acrylic acid / silicone dual-modified epoxy resin, the solvent is one or a combination of two or more of toluene, xylene, pentane, hexane, octane, cyclohexane, cyclohexanone, toluene-cyclohexanone, methanol, ethanol, isopropanol, n-butanol, mixed propanol, acetone, methyl butyl ketone, methyl isobutyl ketone, isophorone, and cyclohexanone.

[0022] More preferably, in the preparation method of acrylic acid / organic silicone dual-modified epoxy resin, the reaction conditions in step (1) are: temperature 40°C to 120°C, time 2 to 8 hours.

[0023] More preferably, in the method for preparing acrylic acid / silicone dual-modified epoxy resin, the reaction conditions in step (2) are: temperature 40°C to 120°C, time 2 to 8 hours.

[0024] Preferably, the acrylic / silicone dual-modified epoxy resin is obtained by reacting an organic alkoxy polysiloxane and an acrylic monomer compound with a multifunctional epoxy resin respectively; the weight ratio of the organic alkoxy polysiloxane, acrylic monomer compound and multifunctional epoxy resin is 20-30:10-25:100.

[0025] Preferably, the one-component light-heat dual-curing epoxy resin three-proof coating comprises, by weight, 100 parts of acrylic acid / silicone dual-modified epoxy resin, 10-20 parts of diluent, 8-13 parts of epoxy curing agent, and 2-4 parts of photoinitiator.

[0026] Preferably, the epoxy curing agent is a latent epoxy curing agent.

[0027] Preferably, the diluent is one or a combination of two or more of allyl glycidyl ether, methacrylate glycidyl ether, and 4-hydroxybutyl acrylate glycidyl ether.

[0028] Preferably, the epoxy curing agent is one or a combination of two or more selected from the group consisting of modified aliphatic amines, aromatic diamines, dicyandiamides, imidazoles, organic acid anhydrides, organic hydrazides, Lewis acid-amine complexes, and microcapsules.

[0029] Preferably, the raw materials of the one-component light-heat dual-curing epoxy resin conformal coating further include 8 to 20 parts of a toughening agent (in parts by mass, corresponding to every 100 parts of acrylic acid / silicone dual-modified epoxy resin), and the toughening agent is a liquid rubber toughened epoxy resin.

[0030] More preferably, the raw materials of the one-component light-heat dual-curing epoxy resin three-proof coating also include 10 to 16 parts of a toughening agent (calculated by mass, corresponding to every 100 parts of acrylic acid / silicone dual-modified epoxy resin); the toughening agent is one or a combination of two or more of silicone rubber, polyurethane rubber, carboxyl-terminated liquid nitrile rubber, liquid polysulfide rubber, acrylate rubber, and chloroprene rubber.

[0031] Preferably, the raw materials of the one-component light-heat dual-curing epoxy resin conformal coating further include 0.2 to 2 parts of a defoamer (in parts by mass, corresponding to every 100 parts of acrylic acid / silicone dual-modified epoxy resin), and the defoamer is a silicone oil defoamer.

[0032] More preferably, the raw materials of the one-component light-heat dual-curing epoxy resin conformal coating further include 0.5 to 1 part of a defoamer (in parts by mass, corresponding to every 100 parts of acrylic acid / silicone dual-modified epoxy resin).

[0033] Preferably, the raw materials of the one-component light-heat dual-curing epoxy resin conformal coating further include 0.2 to 2 parts of a leveling agent (in parts by mass, corresponding to every 100 parts of acrylic acid / silicone dual-modified epoxy resin), and the leveling agent is a siloxane-type epoxy floor leveling agent.

[0034] More preferably, the raw materials of the one-component light-heat dual-curing epoxy resin conformal coating further include 0.5 to 1 part of a leveling agent (in parts by mass, corresponding to every 100 parts of acrylic acid / silicone dual-modified epoxy resin).

[0035] The present invention has the following beneficial effects: the conformal coating of the present invention has excellent adhesion to PCB circuit boards, and has the characteristics of rapid photoinitiated curing and high toughness; it avoids the molecular migration problem of the photoinitiator in the coating and significantly improves the weather resistance of the conformal coating.

[0036] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0038] Figure 1 is the photoinitiator of Example 1 of the present invention 1 H-NMR spectrum;

[0039] Figure 2 is the photoinitiator of Example 1 of the present invention13 C-NMR spectrum;

[0040] Figure 3 This is the ultraviolet absorption spectrum of the photoinitiator of Example 1 of the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, scheme and beneficial technology of the present invention clearer, the present invention is further described in detail below with reference to the embodiments and drawings. It should be noted that the embodiments described in this specification are only for explaining the present invention and are not intended to limit the present invention.

[0042] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and similarly, any upper limit can be combined with any other upper limit to form an unspecified range. In addition, although not explicitly stated, each point or individual value between the endpoints of a range is included in the range. Thus, each point or individual value can serve as its own lower limit or upper limit and be combined with any other point or individual value, or with other lower limits or upper limits, to form an unspecified range.

[0043] In the description of this article, it should be noted that, unless otherwise specified, "above" and "below" are inclusive of the number itself, and the "multiple" in "one or more" means two or more, and the "multiple" in "one or more" means two or more.

[0044] The embodiment of the present invention provides a one-component light-heat dual-curing epoxy resin conformal coating, which comprises, by weight, 100 parts of acrylic acid / organic silicone dual-modified epoxy resin, 8-25 parts of diluent, 6-18 parts of epoxy curing agent, and 1-6 parts of photoinitiator;

[0045] The acrylic acid / organic silicon double-modified epoxy resin is obtained by reacting an organic alkoxy polysiloxane and an acrylic monomer compound with a multifunctional epoxy resin respectively;

[0046] The diluent is a glycidyl ether of acrylic acid compound;

[0047] The photoinitiator is an epoxyalkyl anthracene ether compound, and its chemical structure is:

[0048] ;

[0049] Among them, R 1 represents hydrogen, ethyl or chlorine, R 2 represents a C2~C6 alkylene group, R 3 represents hydrogen, methyl or ethyl.

[0050] Acrylic / silicone dual-modified epoxy resin is an epoxy resin with acrylic functional groups and silicone flexible groups introduced into it. The acrylic functional groups help to achieve rapid curing after photoinitiation, and the introduction of silicone flexible groups improves the toughness and hydrophobicity of the coating.

[0051] Using acrylic acid glycidyl ether compounds as raw materials, on the one hand, reduces the viscosity of the resulting coating, making the coating easy to operate during spraying, brushing, etc.; the acrylic acid group further enhances the photocuring activity, and the glycerol ether group ensures the thermal curing properties, making the coating cure faster and having a better curing effect, which together ensures that the three-proof coating has excellent comprehensive performance.

[0052] As the photoinitiator of this system, epoxy alkyl anthracene ether compound not only has good photocuring activity, but its epoxy active group can also enable the initiator to participate in thermal curing, effectively reducing the phenomenon of small molecule migration and effectively improving the adhesion and weather resistance of the coating.

[0053] To prepare the single-component, dual-curing epoxy resin conformal coating, simply mix all the ingredients thoroughly. After application, the coating can be cured under 365 nm light for 10-60 seconds, followed by baking at 80-120°C for 1-6 hours to form a dense protective coating.

[0054] The one-component photothermal dual-curing epoxy resin conformal coating provided by the embodiment of the present invention has the following advantages: the conformal coating of the embodiment of the present invention has excellent adhesion to PCB circuit boards, and has the characteristics of rapid photoinitiated curing and high toughness; it avoids the problem of molecular migration of the photoinitiator in the coating and significantly improves the weather resistance of the conformal coating.

[0055] In an embodiment of the present invention, the weight ratio of the organoalkoxy polysiloxane, the acrylic monomer compound, and the multifunctional epoxy resin is 15-40:5-35:100.

[0056] In some embodiments of the present invention, the multifunctional epoxy resin is a multifunctional glycidylamine resin.

[0057] In some embodiments of the present invention, the multifunctional epoxy resin is one or a combination of two or more of bisphenol A glycidyl ether, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether methane, triglycidyl-p-aminophenol, triglycidyl triisocyanate, tetraglycidyl diaminodiphenylmethane, tetraglycidyl xylene diamine, tetraglycidyl-1,3,-bisaminomethylcyclohexylamine and their homologues and derivatives.

[0058] In some embodiments of the present invention, the active group of the organoalkoxypolysiloxane is: -SiRn (OR ， ) 3-n , where R represents H, Me, Et, Bu, Ph, Pr, C6H4CH2, C8H 17 、C 12 H 25 One of the ， It represents one of H, Me, Et, and Bu.

[0059] In some embodiments of the present invention, the acrylic monomer is one or a combination of two or more of acrylic acid, methacrylic acid, acrylic anhydride, and acetic acrylic anhydride.

[0060] In an embodiment of the present invention, the preparation method of the acrylic acid / silicone dual-modified epoxy resin comprises:

[0061] (1) A multifunctional epoxy resin and an organic alkoxy polysiloxane undergo dealcoholization reaction in a solvent under catalytic conditions to obtain a uniform liquid;

[0062] (2) The obtained uniform liquid is mixed with an acrylic acid monomer compound, reacted under catalytic conditions, and the solvent is removed to obtain the product.

[0063] In some embodiments of the present invention, in the method for preparing acrylic acid / silicone dual-modified epoxy resin, the catalyst in step (1) is one or a combination of two or more of sodium ethoxide, potassium ethoxide, hydrochloric acid, acetic acid, AlCl3, TiCl3, SnCl3, ZrCl4, BF3, and ZnCl2.

[0064] In some embodiments of the present invention, in the method for preparing an acrylic acid / silicone dual-modified epoxy resin, the catalyst in step (2) is one or a combination of two or more of N,N-dimethylaniline, N,N-dimethylbenzylamine, trimethylbenzylammonium chloride, tetraethylammonium bromide, triphenylphosphine, triphenylantimony, and chromium acetylacetonate.

[0065] In some embodiments of the present invention, in the preparation method of acrylic acid / silicone dual-modified epoxy resin, the solvent is one or a combination of two or more of toluene, xylene, pentane, hexane, octane, cyclohexane, cyclohexanone, toluene-cyclohexanone, methanol, ethanol, isopropanol, n-butanol, mixed propanol, acetone, methyl butyl ketone, methyl isobutyl ketone, isophorone, and cyclohexanone.

[0066] In some embodiments of the present invention, in the method for preparing acrylic acid / silicone dual-modified epoxy resin, the reaction conditions in step (1) are: temperature 40°C~120°C, time 2~8h.

[0067] In some embodiments of the present invention, in the method for preparing acrylic acid / silicone dual-modified epoxy resin, the reaction conditions in step (2) are: temperature 40°C~120°C, time 2~8h.

[0068] In an embodiment of the present invention, the acrylic / silicone dual-modified epoxy resin is obtained by reacting an organic alkoxy polysiloxane and an acrylic monomer compound with a multifunctional epoxy resin respectively; the weight ratio of the organic alkoxy polysiloxane, the acrylic monomer compound and the multifunctional epoxy resin is 20-30:10-25:100.

[0069] In an embodiment of the present invention, the one-component light-heat dual-curing epoxy resin three-proof coating, calculated by mass, includes the following raw materials: 100 parts of acrylic acid / silicone dual-modified epoxy resin, 10-20 parts of diluent, 8-13 parts of epoxy curing agent, and 2-4 parts of photoinitiator.

[0070] In an embodiment of the present invention, the epoxy curing agent is a latent epoxy curing agent.

[0071] In an embodiment of the present invention, the diluent is one or a combination of two or more of allyl glycidyl ether, methacrylate glycidyl ether, and 4-hydroxybutyl acrylate glycidyl ether.

[0072] In an embodiment of the present invention, the epoxy curing agent is one or a combination of two or more of modified aliphatic amines, aromatic diamines, dicyandiamides, imidazoles, organic acid anhydrides, organic hydrazides, Lewis acid-amine complexes and microcapsules.

[0073] 9,10-Dibutoxyl anthracene (DBA) is a widely used photosensitizer, typically used in conjunction with 2,4,5-triaryl imidazole dimer (HABI). When used alone as a photoinitiator, DBA's efficiency in utilizing exposure energy is limited, and its quantum yield needs to be improved, resulting in prolonged exposure times and slower curing. Furthermore, this issue is difficult to address through conventional means, such as increasing the added dosage. Excessively high addition levels can affect coating quality.

[0074] The inventors discovered that upon exposure, the CO bond at the 9,10 position of a 9,10-dialkoxyanthracene photosensitizer breaks, dimerizing the anthracene ring and releasing small alkoxy fragments. These small fragments cannot bind well to the resulting coating, hindering adhesion to the substrate and reducing adhesion, making the coating susceptible to flaking. The present invention incorporates an oxirane functional group into the parent structure of the alkoxyanthracene. This functional group allows for ring-opening during curing of the coating system, significantly reducing the possibility of migration of small molecule fragments after photoinitiation, and thus significantly improving the coating's adhesion and weather resistance.

[0075] In an embodiment of the present invention, the raw materials of the one-component light-heat dual-curing epoxy resin conformal coating further include 8 to 20 parts of a toughening agent (in parts by mass, corresponding to every 100 parts of acrylic acid / silicone dual-modified epoxy resin), and the toughening agent is a liquid rubber toughened epoxy resin.

[0076] In some embodiments of the present invention, the raw materials of the one-component light-heat dual-curing epoxy resin three-proof coating also include 10 to 16 parts of a toughening agent (calculated by mass, corresponding to every 100 parts of acrylic acid / silicone dual-modified epoxy resin); the toughening agent is one or a combination of two or more of silicone rubber, polyurethane rubber, carboxyl-terminated liquid nitrile rubber, liquid polysulfide rubber, acrylate rubber, and chloroprene rubber.

[0077] In an embodiment of the present invention, the raw materials of the one-component light-heat dual-curing epoxy resin conformal coating further include 0.2 to 2 parts of a defoaming agent (in parts by mass, corresponding to every 100 parts of acrylic acid / silicone dual-modified epoxy resin), and the defoaming agent is a silicone oil defoaming agent.

[0078] In some embodiments of the present invention, the raw materials of the one-component light-heat dual-curing epoxy resin conformal coating further include 0.5 to 1 part of a defoamer (in parts by mass, corresponding to every 100 parts of acrylic acid / silicone dual-modified epoxy resin).

[0079] In an embodiment of the present invention, the raw materials of the one-component light-heat dual-curing epoxy resin conformal coating further include 0.2 to 2 parts of a leveling agent (in parts by mass, corresponding to every 100 parts of acrylic acid / silicone dual-modified epoxy resin), and the leveling agent is a siloxane-type epoxy floor leveling agent.

[0080] In some embodiments of the present invention, the raw materials of the one-component light-heat dual-curing epoxy resin conformal coating further include 0.5 to 1 part of a leveling agent (in parts by mass, corresponding to every 100 parts of acrylic / silicone dual-modified epoxy resin).

[0081] Example

[0082] The following examples describe the present disclosure in more detail and are intended to be illustrative only, as various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight. Unless otherwise stated, all reagents used in the examples are available through conventional commercial sources or synthesized according to conventional methods and can be used directly without further processing. Unless otherwise stated, all instruments used in the examples are available through conventional commercial sources.

[0083] Example 1

[0084] The single-component light-heat dual-curing epoxy resin conformal coating of this embodiment comprises the following raw materials in parts by mass:

[0085] Acrylic acid / silicone double-modified epoxy resin (homemade) 100 parts;

[0086] Diluent (allyl glycidyl ether) 13 parts;

[0087] Toughening agent (EP-2000) 10 parts;

[0088] Epoxy curing agent (dicyandiamide) 8 parts;

[0089] Photoinitiator (homemade) 3 parts;

[0090] Defoaming agent (KS-603) 0.8 parts;

[0091] Leveling agent (BYK-333) 0.8 parts

[0092] The homemade acrylic / organic silicone dual-modified epoxy resin of this embodiment is obtained by reacting an organic alkoxy polysiloxane and an acrylic monomer compound with a multifunctional epoxy resin respectively; the weight ratio of the organic alkoxy polysiloxane, the acrylic monomer compound, and the multifunctional epoxy resin is 25:12.5:100; the active group of the organic alkoxy polysiloxane is: -SiMe2(OMe); the acrylic monomer compound is acrylic acid; and the multifunctional epoxy resin is bisphenol A glycidyl ether resin.

[0093] The preparation method of acrylic acid / organic silicon double modified epoxy resin in this embodiment is as follows:

[0094] (1) Add 80g of bisphenol A glycidyl ether resin and 20g of alkoxypolysiloxane into a three-necked flask, dissolve in toluene, add 1g of AlCl3 (catalyst) dropwise, control the temperature at 100℃ and distill to remove the alcoholate, react for 6h, and obtain a transparent and uniform liquid;

[0095] (2) Add 10g of acrylic acid according to the ratio, add 1g of N,N-dimethylaniline (catalyst) dropwise, control the temperature at 120℃, react for 8h, and obtain a transparent and uniform liquid. Remove the solvent by vacuum distillation to obtain acrylic acid / silicone dual-modified epoxy resin.

[0096] The main chemical reactions involved are as follows:

[0097] .

[0098] The self-made photoinitiator in this example is an epoxyalkyl anthracene ether compound, 9,10-di-(1,2-epoxy-n-heptyloxy)anthracene, whose chemical structure can be expressed as follows:

[0099] .

[0100] Figure 1 is the photoinitiator of this embodiment 1 H-NMR spectrum; 1 H NMR (400 MHz, CDCl3): δ 8.28 (d, J =10.01 Hz, 4H), 7.49 (d, J = 7.2 Hz, 4H), 4.17 (t, J = 6.59 Hz, 4H), 3.03 – 2.91(m, 2H), 2.77 (t, J = 4.53 Hz, 2H), 2.55 – 2.44 (m, 2H), 2.06 (p, J = 6.86 Hz, 4H), 1.79 – 1.56 (m, 12H).

[0101] Figure 2 is the photoinitiator of this embodiment 13 C-NMR spectrum; 13 C NMR (100 MHz, CDCl3): δ 147.5,125.2, 125.1, 122.7, 75.9, 52.3, 47.2, 32.5, 30.6, 26.2, 26.1.

[0102] Figure 3 FIG2 is the ultraviolet absorption spectrum of the photoinitiator of this embodiment. From the figure, it can be seen that the photoinitiator has multiple absorption peaks in the ultraviolet region and can be used for photoinitiation.

[0103] The photoinitiator of this embodiment is prepared by a two-step reaction of anthraquinone and bromoolefin compounds, and the preparation method is as follows:

[0104] ;

[0105] Aliquat 336 represents trioctylmethylammonium chloride, and toluene represents toluene.

[0106] Step 1: To a 50 mL handle flask, add m-chloroperbenzoic acid (4 mmol, 0.81 g) and replace Ar three times. Add 6 mL of anhydrous DCM and stir until the solid dissolves. Then add 7-bromo-1-heptene (2 mmol, 0.35 g) dropwise. After reacting at room temperature for 12 h, the reaction solution is concentrated and distilled to obtain epoxy bromide heptane.

[0107] Step 2: Anthraquinone (2.0 mmol, 490 mg), sodium dithionite (6.0 mmol, 1040 mg), and methyltrioctylammonium chloride (0.2 mmol, 80 mg) were placed in a 20 mL Schlenk tube with a branched tube and the atmosphere was replaced with argon three times. 3.2 mL of toluene was added to the reaction system. A 35 wt% NaOH solution (1.8 mmol, 210 mg) was added dropwise while stirring. The temperature was raised to 35°C and the reaction was continued for 30 min. A 35 wt% NaOH solution (18.2 mmol, 2080 mg) was then slowly added dropwise to the reaction system over 10 min. The temperature was then raised to 45°C and the reaction was continued for 1 h. Bromoheptane (8.0 mmol, 1544 mg) was slowly added dropwise to the reaction system, and the temperature was raised to 60°C and the reaction was continued for 12 h. After the reaction was complete, 10 mL of deionized water was added to the reaction system. The reaction mixture was transferred to a separatory funnel and extracted three times with dichloromethane (DCM). The organic phase was dried over anhydrous Na₂SO₄, and the solvent was removed by distillation under reduced pressure. The crude product was separated by column chromatography to yield 9,10-di-(1,2-epoxy-n-heptyloxy)anthracene (615 mg, 76% yield).

[0108] Example 2

[0109] The single-component light-heat dual-curing epoxy resin conformal coating of this embodiment comprises the following raw materials in parts by mass:

[0110] Acrylic acid / silicone double-modified epoxy resin (homemade) 100 parts;

[0111] Diluent (glycidyl methacrylate) 20 parts;

[0112] Toughening agent (carboxyl-terminated liquid nitrile rubber) 16 parts;

[0113] Epoxy curing agent (m-phenylenediamine) 13 parts;

[0114] Photoinitiator (homemade) 3 parts;

[0115] Defoaming agent (KS-603) 0.5 parts;

[0116] Leveling agent (BYK-333) 0.5 parts.

[0117] The homemade acrylic / organic silicone dual-modified epoxy resin of this example is obtained by reacting an organoalkoxy polysiloxane and an acrylic monomer compound with a multifunctional epoxy resin, respectively. The weight ratio of the organoalkoxy polysiloxane, acrylic monomer compound, and multifunctional epoxy resin is 24.66:19.18:100. The active group of the organoalkoxy polysiloxane is -SiEt(OMe)2; the acrylic monomer compound is methacrylic acid; and the multifunctional epoxy resin is TDE-85.

[0118] The preparation method of acrylic acid / organic silicon double modified epoxy resin in this embodiment is as follows:

[0119] (1) Add 73g of TDE-85 and 18g of alkoxypolysiloxane into a three-necked flask, dissolve in xylene, add 0.8g of sodium ethoxide (catalyst) dropwise, control the temperature at 90°C and distill to remove the alcoholate. React for 7h to obtain a transparent and uniform liquid.

[0120] (2) Add 14 g of methacrylic acid according to the ratio, add 0.5 g of triphenylphosphine (catalyst) dropwise, control the temperature at 100 ° C, react for 8 hours, and obtain a transparent and uniform liquid. Remove the solvent by vacuum distillation to obtain an acrylic acid / silicone double-modified epoxy resin.

[0121] The self-made photoinitiator in this example is an epoxyalkyl anthracene ether compound, 9,10-di-(1,2-epoxy-n-octyloxy) anthracene, whose chemical structure can be expressed as:

[0122] .

[0123] The photoinitiator of this embodiment is prepared by a two-step reaction of anthraquinone and bromoolefin compounds, and the preparation method is as follows:

[0124] ;

[0125] Aliquat 336 represents trioctylmethylammonium chloride, and toluene represents toluene.

[0126] Step 1: To a 50 mL handle flask, add m-chloroperbenzoic acid (4 mmol, 0.81 g) and replace Ar three times. Add 6 mL of anhydrous DCM and stir until the solid dissolves. Then add 8-bromo-1-octene (2 mmol, 0.38 g) dropwise. After reacting at room temperature for 12 h, the reaction solution is concentrated and distilled to obtain epoxy bromide octane.

[0127] Step 2: Anthraquinone (2.0 mmol, 490 mg), sodium dithionite (6.0 mmol, 1040 mg), and methyltrioctylammonium chloride (0.2 mmol, 80 mg) were placed in a 20 mL Schlenk tube with a branched tube and the atmosphere was replaced with argon three times. 3.2 mL of toluene was added to the reaction system. A 35 wt% NaOH solution (1.8 mmol, 210 mg) was added dropwise while stirring. The temperature was raised to 35°C and the reaction was continued for 30 min. A 35 wt% NaOH solution (18.2 mmol, 2080 mg) was then slowly added dropwise to the reaction system over 10 min. The temperature was then raised to 45°C and the reaction was continued for 1 h. Epoxyoctane (8 mmol, 1657 mg) was slowly added dropwise to the reaction system. The temperature was raised to 60°C and the reaction was continued for 12 h. After the reaction was complete, 10 mL of deionized water was added to the reaction system. The reaction mixture was transferred to a separatory funnel and extracted three times with dichloromethane (DCM). The organic phase was dried over anhydrous Na₂SO₄, and the solvent was removed by distillation under reduced pressure. The crude product was separated by column chromatography to yield 9,10-di-(1,2-epoxyoctyloxy)anthracene (586 mg, 63% yield).

[0128] Example 3

[0129] The single-component light-heat dual-curing epoxy resin conformal coating of this embodiment comprises the following raw materials in parts by mass:

[0130] Acrylic acid / silicone double-modified epoxy resin (homemade) 100 parts;

[0131] Diluent (allyl glycidyl ether) 15 parts;

[0132] Toughening agent (carboxyl-terminated liquid nitrile rubber) 12 parts;

[0133] Epoxy curing agent (dicyandiamide) 10 parts;

[0134] Photoinitiator (homemade) 2.5 parts;

[0135] Defoaming agent (KS-603) 0.625 parts;

[0136] Leveling agent (BYK-333) 0.625 parts

[0137] The homemade acrylic / silicone dual-modified epoxy resin of this embodiment is obtained by reacting an organic alkoxy polysiloxane and an acrylic monomer compound with a multifunctional epoxy resin respectively; the weight ratio of the organic alkoxy polysiloxane, the acrylic monomer compound, and the multifunctional epoxy resin is 20:21.67:100; the active group of the organic alkoxy polysiloxane is: -SiMe(OMe)2; the acrylic monomer compound is acrylic acid; and the multifunctional epoxy resin is AG-80 epoxy resin.

[0138] The preparation method of acrylic acid / organic silicon double modified epoxy resin in this embodiment is as follows:

[0139] (1) Add 60g of AG-80 epoxy resin and 12g of alkoxypolysiloxane into a three-necked flask, dissolve in toluene, add 0.4g of SnCl3 (catalyst) dropwise, control the temperature at 100℃ and distill to remove the alcoholate, react for 6h, and obtain a transparent and uniform liquid;

[0140] (2) Add 13g of acrylic acid according to the ratio, add 1g of trimethylbenzyl ammonium chloride (catalyst) dropwise, control the temperature at 110℃, react for 8h, and obtain a transparent and uniform liquid. Remove the solvent by vacuum distillation to obtain acrylic acid / silicone dual-modified epoxy resin.

[0141] The self-made photoinitiator in this example is an epoxyalkyl anthracene ether compound, 9,10-bis(1,2-2-(bromomethyl)-3-ethyloxirane)oxy)anthracene, whose chemical structure can be expressed as:

[0142] .

[0143] The photoinitiator of this embodiment is prepared by a two-step reaction of anthraquinone and bromoolefin compounds, and the preparation method is as follows:

[0144] ;

[0145] Aliquat 336 represents trioctylmethylammonium chloride, and toluene represents toluene.

[0146] Step 1: To a 50 mL handle flask, add m-chloroperbenzoic acid (4 mmol, 0.81 g) and replace Ar three times. Add 6 mL of anhydrous DCM and stir until the solid dissolves. Then add 1-bromo-2-pentene (2 mmol, 0.30 g) dropwise. After reacting at room temperature for 12 h, the reaction solution is concentrated and distilled to obtain 2-(bromomethyl)-3-ethyloxirane.

[0147] Step 2: Anthraquinone (2.0 mmol, 490 mg), sodium dithionite (6.0 mmol, 1040 mg), and methyltrioctylammonium chloride (0.2 mmol, 80 mg) were placed in a 20 mL Schlenk tube with a branched tube and the atmosphere was replaced with argon three times. 3.2 mL of toluene was added to the reaction system. A 35 wt% NaOH solution (1.8 mmol, 210 mg) was added dropwise while stirring. The temperature was raised to 35°C and the reaction was continued for 30 min. A 35 wt% NaOH solution (18.2 mmol, 2080 mg) was then slowly added dropwise to the reaction system over 10 min. The temperature was then raised to 45°C and the reaction was continued for 1 h. 2-(Bromomethyl)-3-ethyloxirane (8 mmol, 1296 mg) was slowly added dropwise to the reaction system. The temperature was raised to 60°C and the reaction was continued for 12 h. After the reaction was complete, 10 mL of deionized water was added to the reaction system. The reaction mixture was transferred to a separatory funnel and extracted three times with dichloromethane (DCM). The organic phase was dried over anhydrous Na₂SO₄, and the solvent was removed by distillation under reduced pressure. The crude product was separated by column chromatography to yield 9,10-bis(1,2-(bromomethyl)-3-ethyloxiranyl)oxy)anthracene (573 mg, 76% yield).

[0148] Comparative Example 1

[0149] The coating raw materials of this comparative example are basically the same as those of Example 1, except that, instead of preparing acrylic acid / organic silicone double-modified epoxy resin, the raw materials of acrylic acid / organic silicone double-modified epoxy resin - polydimethylsiloxane, acrylic acid, and bisphenol A glycidyl ether resin are directly used as the raw materials of the coating according to the original proportion.

[0150] Comparative Example 2

[0151] The coating raw materials of this comparative example are basically the same as those of Example 1, except that the acrylic acid / organic silicon double-modified epoxy resin is not used, but the bisphenol A glycidyl ether resin in Example 1 is used instead.

[0152] Comparative Example 3

[0153] The coating raw materials of this comparative example are basically the same as those of Example 1, except that the homemade photoinitiator is not used, but the traditional 1173 photoinitiator is used instead.

[0154] Detection and analysis

[0155] The performance tests of various indicators were conducted on the coatings of each embodiment and comparative example, as well as similar conformal coating products on the market. The test methods are as follows:

[0156] Appearance: Visual inspection; Viscosity: GB / T 2794-2013; Volume resistivity: GB1410-2006; Dielectric strength: GB / T1408.1-2016; Hardness: GB / T 2411-2008; Tensile strength: GB / T 1040-2018; Adhesion test: GB / T9286-1998; Environmental resistance test: IPC-TM-650.

[0157] The coating curing method during testing is: after application, use a 365nm medium pressure mercury lamp with 1000~2000mj / cm 2 Expose to light for 60 seconds and record the surface dry time, then bake at 100°C for 2 hours.

[0158] The test results are shown in Table 1.

[0159] Table 1 Performance test results of coatings of various embodiments and comparative examples, as well as commercially available products

[0160] ;

[0161] It can be seen from the experimental data in Table 1 that the one-component light-heat dual-curing epoxy resin three-proof coating prepared by the present invention has the characteristics of rapid surface drying, and the adhesion has achieved level 0. At the same time, compared with existing similar products, its UV resistance, oil resistance, and solvent resistance have been significantly improved. The coating of the embodiment of the present invention forms an epoxy three-dimensional network structure after thermal curing, which improves the strength of the coating and makes it have better mechanical properties and weather resistance. After the epoxy resin structure was changed relative to the method of the present invention, Comparative Example 1 and Comparative Example 2 failed to cure; after the photoinitiator was replaced relative to the method of the present invention, the weather resistance of the resulting coating decreased.

Claims

1. A one-component light-heat dual-curing epoxy resin conformal coating, characterized in that: The raw materials include, by mass: 100 parts of acrylic acid / organic silicon double-modified epoxy resin, 8 to 25 parts of diluent, 6 to 18 parts of epoxy curing agent, and 1 to 6 parts of photoinitiator; The preparation method of the acrylic acid / organic silicon double-modified epoxy resin comprises: (1) a multifunctional epoxy resin and an organic alkoxy polysiloxane are subjected to dealcoholization reaction in a solvent under catalytic conditions to obtain a uniform liquid; (2) mixing the obtained uniform liquid with an acrylic monomer compound, reacting under catalytic conditions, and removing the solvent to obtain the product; The weight ratio of the organic alkoxy polysiloxane, the acrylic monomer compound and the multifunctional epoxy resin is 15-40:5-35:100; The catalyst in step (1) is one or a combination of two or more of sodium ethoxide, potassium ethoxide, hydrochloric acid, acetic acid, AlCl3, TiCl3, SnCl3, ZrCl4, BF3, and ZnCl2; The catalyst in step (2) is one or a combination of two or more of N,N-dimethylaniline, N,N-dimethylbenzylamine, trimethylbenzylammonium chloride, tetraethylammonium bromide, triphenylphosphine, triphenylantimony, and chromium acetylacetonate; The reaction conditions in step (1) are: temperature 40°C to 120°C, time 2 to 8 hours; The reaction conditions in step (2) are: temperature 40°C to 120°C, time 2 to 8 hours; The multifunctional epoxy resin is one or a combination of two or more of bisphenol A glycidyl ether, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether methane, triglycidyl-p-aminophenol, triglycidyl triisocyanate, tetraglycidyl diaminodiphenylmethane, tetraglycidyl xylenediamine, and tetraglycidyl-1,3-bisaminomethylcyclohexylamine; The active group of the organoalkoxy polysiloxane is: -SiR n (OR ， ) 3-n , where R represents Me, Et, Bu, Ph, Pr, C6H4CH2, C8H 17 、C 12 H 25 One of the ， Indicates one of Me, Et, and Bu; The diluent is a glycidyl ether of acrylic acid compound; The photoinitiator is an epoxyalkyl anthracene ether compound, and its chemical structure is: Among them, R 1 represents hydrogen, ethyl or chlorine, R 2 represents a C2-C6 alkylene group, R 3 represents hydrogen, methyl or ethyl.

2. The one-component light-heat dual-curing epoxy resin conformal coating according to claim 1, characterized in that: The acrylic monomer is one or a combination of two or more of acrylic acid, methacrylic acid, and acrylic anhydride.

3. The one-component light-heat dual-curing epoxy resin conformal coating according to claim 1 or 2, characterized in that: The weight ratio of the organic alkoxy polysiloxane, the acrylic monomer compound and the multifunctional epoxy resin is 20-30:10-25:

100.

4. The one-component light-heat dual-curing epoxy resin conformal coating according to claim 3, characterized in that: The solvent is one or a combination of two or more of toluene, xylene, pentane, hexane, octane, cyclohexane, cyclohexanone, toluene-cyclohexanone, methanol, ethanol, isopropanol, n-butanol, mixed propanol, acetone, methyl butyl ketone, methyl isobutyl ketone, isophorone, and cyclohexanone.

5. The one-component light-heat dual-curing epoxy resin conformal coating according to claim 1 or 2, characterized in that: The raw materials include, by mass: 100 parts of acrylic acid / organic silicone double-modified epoxy resin, 10-20 parts of diluent, 8-13 parts of epoxy curing agent, and 2-4 parts of photoinitiator; The epoxy curing agent is a latent epoxy curing agent.

6. The one-component light-heat dual-curing epoxy resin conformal coating according to claim 1 or 2, characterized in that: The diluent is one or a combination of methacrylate glycidyl ether and 4-hydroxybutyl acrylate glycidyl ether; The epoxy curing agent is one or a combination of two or more of modified aliphatic amines, aromatic diamines, dicyandiamides, imidazoles, organic acid anhydrides, organic hydrazides, Lewis acid-amine complexes and microcapsules.

7. The one-component light-heat dual-curing epoxy resin conformal coating according to claim 1 or 2, characterized in that: The raw materials also include 8 to 20 parts of a toughening agent; the raw materials also include 0.2 to 2 parts of a defoaming agent, which is a silicone oil defoaming agent; the raw materials also include 0.2 to 2 parts of a leveling agent, which is a silicone type epoxy floor leveling agent.

8. The one-component light-heat dual-curing epoxy resin conformal coating according to claim 7, characterized in that: The raw materials also include 10 to 16 parts of a toughening agent; the toughening agent is one or a combination of two or more of silicone rubber, polyurethane rubber, carboxyl-terminated liquid nitrile rubber, liquid polysulfide rubber, acrylic rubber, and chloroprene rubber; the raw materials also include 0.5 to 1 part of a defoaming agent; and the raw materials also include 0.5 to 1 part of a leveling agent.

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