A solder resist dry film and preparation method thereof

Abstract

The present invention relates to the field of G03F technology, and more specifically, to a solder mask dry film and a method for preparing the same. The solder mask dry film comprises, by weight, 15-40 parts of an anhydride-modified epoxy acrylic resin, 20-30 parts of an acrylate, 10-20 parts of a curing agent, 1-10 parts of a photoinitiator, and 2-40 parts of a solvent. The solder mask dry film obtained in this application exhibits excellent flatness and chemical resistance to nickel-palladium-gold (NiPdAu), without defects such as gold seepage, whitening of the film surface, or detachment.

Description

Technical Field

[0001] The present invention relates to the field of G03G technology, and more particularly, to a solder resist dry film and a preparation method thereof. Background Art

[0002] Solder mask dry film is a dry film type solder mask ink that can be alkaline developed. The use of solder mask dry film provides a technical solution for reducing processes, reducing costs, being environmentally friendly, and being automated in the PCB field. CN201710940580 provides a UV-curable solder mask ink by using acrylic monomers, barium sulfate, pigments, and photoinitiators. It has a good curing rate. However, the viscosity stability of the solder mask ink is poor, which affects its later use. It also has poor chemical resistance to nickel palladium gold. CN201911381273 obtains an ink by using carboxyl acrylate compounds, phosphorus-containing acrylates, nitrogen-containing acrylates, modified epoxy acrylates, silica, curing agents, photoinitiators, and pigments. It has certain wear resistance. However, the ink also has the technical problem of poor chemical resistance to nickel palladium gold. At the same time, the flatness of the dry film obtained from the ink needs to be improved. Summary of the Invention

[0003] In response to some problems existing in the prior art, the first aspect of the present invention provides a solder mask dry film, the preparation raw materials of which include 15-40 parts of anhydride-modified epoxy acrylic resin, 20-30 parts of acrylate, 10-20 parts of curing agent, 1-10 parts of photoinitiator, and 2-40 parts of solvent, by weight.

[0004] In one embodiment, the raw materials for preparing the solder resist dry film further include 20-30 parts by weight of silicate powder.

[0005] In one embodiment, the raw materials for preparing the solder resist dry film further include 1-5 parts by weight of pigment.

[0006] In a preferred embodiment, the raw materials for preparing the solder resist dry film include, by weight, 32 parts of anhydride-modified epoxy acrylic resin, 25 parts of acrylate, 15 parts of curing agent, 7 parts of photoinitiator, 20-30 parts of silicate powder, 3 parts of pigment, and 30 parts of solvent.

[0007] In one embodiment, the anhydride in the anhydride-modified epoxy acrylic resin is dehydrated malic anhydride and / or methyltetrahydrophthalic anhydride.

[0008] Preferably, the weight ratio of the dehydrated malic anhydride to methyltetrahydrophthalic anhydride is (4.5-7):1, more preferably 5:1.

[0009] The applicant unexpectedly discovered that when the acid anhydride is dehydrated malic anhydride and methyltetrahydrophthalic anhydride, especially when the weight ratio is (4.5-7):1, the prepared solder resist dry film avoids the problems of poor flatness and pinholes caused by silicate powder.

[0010] In one embodiment, the acid value of the anhydride-modified epoxy acrylic resin is 20-200 mg KOH / g. Preferably, the acid value of the anhydride-modified epoxy acrylic resin is 100-110 mg KOH / g, more preferably 105 mg KOH / g.

[0011] In one embodiment, the raw materials for preparing the anhydride-modified epoxy acrylic resin include epoxy acrylic resin, acid anhydride, triethylamine, and hydroquinone.

[0012] In one embodiment, the epoxy acrylic resin has a viscosity of 5000-7000 mPa·s at 25° C.

[0013] The viscosity described in this application is measured using a lattice tube viscometer.

[0014] In the present application, the epoxy acrylic resin having a viscosity of 5000-7000 mPa·s at 25° C. was purchased from Shandong Kepler Biotechnology Co., Ltd., model number kpl-12365.

[0015] In one embodiment, the preparation method of the anhydride-modified epoxy acrylic resin comprises: mixing epoxy acrylic resin, acid anhydride, triethylamine, and hydroquinone, and reacting the mixture at 80° C. to obtain the epoxy acrylic resin.

[0016] In the preparation method of the anhydride-modified epoxy acrylic resin of the present application, those skilled in the art may make conventional selections for the undisclosed parts in the present application to obtain the anhydride-modified epoxy acrylic resin with an acid value of 20-200 mg KOH / g.

[0017] The applicant unexpectedly discovered in experiments that when the viscosity of the epoxy acrylic resin at 25°C is 5000-7000 mPa.s, the anhydride-modified epoxy acrylic resin prepared at this time has an acid value of 20-200 mg KOH / g, especially when the acid value of the anhydride-modified epoxy acrylic resin is 100-110 mg KOH / g. The resulting solder mask dry film also has chemical nickel-palladium-gold resistance when the thickness exceeds 25 μm, without defects such as gold penetration, whitening of the film surface, and detachment. At the same time, the solder mask dry film obtained using this anhydride-modified epoxy acrylic resin avoids the problem of subsequent dilution during storage caused by high local viscosity of light-curing and heat-curing resin compositions, which increases the difficulty of dry film preparation. The applicant believes that this may be due to the fact that within the specific acid value range of this application, the anhydride-modified epoxy acrylic resin and the triethylene glycol diacrylate and neopentyl glycol diacrylate in this application can cooperate with each other during the preparation process, increasing the distance between molecules during the reaction while achieving a suitable cross-linked network. This cross-linked network also ensures that the molecules of the composition in the system are subjected to isotropic forces during storage.

[0018] In one embodiment, the acrylate has 10-15 carbon atoms.

[0019] Preferably, the acrylate is triethylene glycol diacrylate and neopentyl glycol diacrylate. Further preferably, the weight ratio of triethylene glycol diacrylate to neopentyl glycol diacrylate is (2-5):1. More preferably, the weight ratio of triethylene glycol diacrylate to neopentyl glycol diacrylate is 3.5:1.

[0020] In one embodiment, the silicate powder is bentonite and / or talc.

[0021] Preferably, the silicate powder is bentonite.

[0022] The bentonite described in this application was purchased from Lingshou County Zhanteng Mineral Products Processing Plant.

[0023] In one embodiment, the solvent is selected from one or more of ketone solvents, aromatic hydrocarbon solvents, petroleum solvents, alcohol ether solvents, and amide solvents.

[0024] Preferably, the solvent is an amide solvent.

[0025] Preferably, the amide solvent is N-methyl-2-pyrrolidone.

[0026] The applicant unexpectedly discovered that when an amide solvent is used in the present application, the drying efficiency is improved during the preparation of the solder resist dry film.

[0027] In one embodiment, the curing agent contains one or more of an epoxy group, an isocyanate group, a cyclic ether group, an oxetane group, and a carbon-carbon double bond, preferably an epoxy group.

[0028] The curing agent described in this application was purchased from Moni Environmental Protection Technology Hebei Co., Ltd., with the brand name E-44.

[0029] The photoinitiator described in this application is not particularly limited and can be routinely selected by those skilled in the art.

[0030] In one embodiment, the photoinitiator is photoinitiator 819.

[0031] The pigments described in this application are not particularly limited, and those skilled in the art can make conventional selections, including red pigments, blue pigments, green pigments, yellow pigments, black pigments, and the like.

[0032] In one embodiment, the pigment is light-fast yellow G, purchased from Jinan Huijinchuan Chemical Co., Ltd.

[0033] In one embodiment, the preparation method of the solder resist dry film includes: mixing and stirring an anhydride-modified epoxy acrylic resin, an acrylate, a curing agent, a photoinitiator and a solvent to obtain a light-curing and heat-curing resin composition, and then diluting it, coating the light-curing and heat-curing resin composition on a carrier film, and treating it at 50°C for 15 minutes to obtain the result.

[0034] In a preferred embodiment, the preparation method of the solder resist dry film comprises: mixing anhydride-modified epoxy acrylic resin, acrylate, curing agent, photoinitiator, solvent and pigment, adding silicate powder, stirring to obtain a light-curing and heat-curing resin composition, and then diluting it, coating the light-curing and heat-curing resin composition on a carrier film, and treating it at 50°C for 15 minutes to obtain the result.

[0035] The carrier film and coating method described in this application are not particularly limited, and those skilled in the art can make conventional selections.

[0036] A second aspect of the present invention provides an application of the solder resist dry film in a PCB board.

[0037] In one embodiment, a method for applying a solder mask dry film to a PCB board includes: pressing one side of the photocurable and thermosetting resin composition of the solder mask dry film to the surface of the PCB board, exposing it using a 365nm wavelength ultraviolet light exposure machine, removing the carrier film, developing it in a 1wt% sodium carbonate aqueous solution at 30°C, and then thermally curing it in a 160°C oven for 60 minutes.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The present application uses a specific ratio of dehydrated malic anhydride and methyltetrahydrophthalic anhydride to modify the epoxy acrylic resin, and the resulting solder mask dry film avoids the problems of poor flatness and pinholes caused by silicate powder.

[0040] (2) The present application uses an epoxy acrylic resin with a specific viscosity to obtain an anhydride-modified epoxy acrylic resin with an acid value of 20-200 mg KOH / g. The obtained solder resist dry film also has chemical nickel-palladium-gold resistance when the thickness exceeds 25 μm, and has no defects such as gold penetration, whitening of the film surface, and falling off. At the same time, the solder resist dry film obtained using the anhydride-modified epoxy acrylic resin avoids the problem of subsequent dilution caused by the high local viscosity of the light-curing and heat-curing resin compositions during storage, which increases the difficulty of dry film preparation.

[0041] (3) The use of the specific amide solvents of this application improves the drying efficiency during the preparation of the solder resist dry film. DETAILED DESCRIPTION

[0042] The present invention is described below by way of specific embodiments, but is not limited to the specific embodiments given below.

[0043] Example

[0044] Example 1

[0045] Example 1 of the present invention provides a solder resist dry film, the preparation raw materials of which are as follows, in parts by weight: 15 parts of anhydride-modified epoxy acrylic resin, 20 parts of acrylate, 10 parts of curing agent, 5 parts of photoinitiator, 10 parts of solvent, 20 parts of silicate powder, and 1 part of pigment.

[0046] An anhydride-modified epoxy acrylic resin with an acid value of 100 mg KOH / g is obtained by reacting epoxy acrylic resin, acid anhydride, triethylamine, and hydroquinone at 80°C. The epoxy acrylic resin has a viscosity of 5000-7000 mPa.s at 25°C and is purchased from Shandong Kepler Biotechnology Co., Ltd. with the model number kpl-12365. The acid anhydride is dehydrated malic anhydride and methyltetrahydrophthalic anhydride in a weight ratio of 4.5:1.

[0047] The acrylate is triethylene glycol diacrylate and neopentyl glycol diacrylate, with a weight ratio of 2:1.

[0048] The curing agent is an epoxy resin curing agent purchased from Moni Environmental Protection Technology Hebei Co., Ltd., with the brand name E-44.

[0049] The photoinitiator is photoinitiator 819.

[0050] The silicate powder is bentonite, purchased from Lingshou County Zhan Teng Mineral Products Processing Plant.

[0051] The pigment is light-fast yellow G, purchased from Jinan Huijinchuan Chemical Co., Ltd.

[0052] The solvent is N-methyl-2-pyrrolidone.

[0053] The preparation method of the solder resist dry film comprises: mixing anhydride-modified epoxy acrylic resin, acrylate, curing agent, photoinitiator, solvent and pigment, adding silicate powder, stirring to obtain a light-curing and heat-curing resin composition, and then coating the light-curing and heat-curing resin composition on a carrier film after dilution, and treating at 50° C. for 15 minutes to obtain the solder resist dry film.

[0054] The solder resist dry film is applied to a PCB board. The specific method is as follows: one side of the light-curing and heat-curing resin composition of the solder resist dry film is pressed against the surface of the PCB board, exposed using a 365nm wavelength ultraviolet light exposure machine, removing the carrier film, developing in a 1wt% sodium carbonate aqueous solution at 30°C, and then heat curing in a 160°C oven for 60 minutes.

[0055] Example 2

[0056] Example 2 of the present invention provides a solder resist dry film, the raw materials for its preparation are as follows, in parts by weight: 40 parts of anhydride-modified epoxy acrylic resin, 30 parts of acrylate, 20 parts of curing agent, 10 parts of photoinitiator, 40 parts of solvent, 30 parts of silicate powder, and 5 parts of pigment.

[0057] An anhydride-modified epoxy acrylic resin with an acid value of 110 mg KOH / g is obtained by reacting epoxy acrylic resin, acid anhydride, triethylamine, and hydroquinone at 80°C. The epoxy acrylic resin has a viscosity of 5000-7000 mPa.s at 25°C and is purchased from Shandong Kepler Biotechnology Co., Ltd. with the model number kpl-12365. The acid anhydride is dehydrated malic anhydride and methyltetrahydrophthalic anhydride in a weight ratio of 7:1.

[0058] The acrylate is triethylene glycol diacrylate and neopentyl glycol diacrylate, with a weight ratio of 5:1.

[0059] The curing agent is an epoxy resin curing agent purchased from Moni Environmental Protection Technology Hebei Co., Ltd., with the brand name E-44.

[0060] The photoinitiator is photoinitiator 819.

[0061] The silicate powder is bentonite, purchased from Lingshou County Zhan Teng Mineral Products Processing Plant.

[0062] The pigment is light-fast yellow G, purchased from Jinan Huijinchuan Chemical Co., Ltd.

[0063] The specific implementation of the method for preparing the solder resist dry film is the same as that of Example 1.

[0064] The solder resist dry film is applied to a PCB board. The specific method is as follows: one side of the light-curing and heat-curing resin composition of the solder resist dry film is pressed against the surface of the PCB board, exposed using a 365nm wavelength ultraviolet light exposure machine, removing the carrier film, developing in a 1wt% sodium carbonate aqueous solution at 30°C, and then heat curing in a 160°C oven for 60 minutes.

[0065] Example 3

[0066] Example 3 of the present invention provides a solder resist dry film, the raw materials for its preparation are as follows, in parts by weight: 32 parts of anhydride-modified epoxy acrylic resin, 25 parts of acrylate, 15 parts of curing agent, 7 parts of photoinitiator, 20-30 parts of silicate powder, 3 parts of pigment, and 30 parts of solvent.

[0067] An anhydride-modified epoxy acrylic resin with an acid value of 105 mg KOH / g is obtained by reacting epoxy acrylic resin, acid anhydride, triethylamine, and hydroquinone at 80°C. The epoxy acrylic resin has a viscosity of 5000-7000 mPa.s at 25°C and is purchased from Shandong Kepler Biotechnology Co., Ltd. with the model number kpl-12365. The acid anhydride is dehydrated malic anhydride and methyltetrahydrophthalic anhydride in a weight ratio of 5:1.

[0068] The acrylate is triethylene glycol diacrylate and neopentyl glycol diacrylate, with a weight ratio of 3.5:1.

[0069] The curing agent is an epoxy resin curing agent purchased from Moni Environmental Protection Technology Hebei Co., Ltd., with the brand name E-44.

[0070] The photoinitiator is photoinitiator 819.

[0071] The silicate powder is bentonite, purchased from Lingshou County Zhan Teng Mineral Products Processing Plant.

[0072] The pigment is light-fast yellow G, purchased from Jinan Huijinchuan Chemical Co., Ltd.

[0073] The specific implementation of the method for preparing the solder resist dry film is the same as that of Example 1.

[0074] The solder resist dry film is applied to a PCB board. The specific method is as follows: one side of the light-curing and heat-curing resin composition of the solder resist dry film is pressed against the surface of the PCB board, exposed using a 365nm wavelength ultraviolet light exposure machine, removing the carrier film, developing in a 1wt% sodium carbonate aqueous solution at 30°C, and then heat curing in a 160°C oven for 60 minutes.

[0075] Example 4

[0076] Example 4 of the present invention provides a solder mask dry film, and its specific implementation method is the same as that of Example 3, except that the anhydride-modified epoxy acrylic resin with an acid value of 250 mg KOH / g is obtained by reacting epoxy acrylic resin, acid anhydride, triethylamine, and hydroquinone at 80°C; the epoxy acrylic resin has a viscosity of 5000-7000 mPa.s at 25°C and is purchased from Shandong Kepler Biotechnology Co., Ltd., model kpl-12365; the acid anhydride is dehydrated malic anhydride and methyltetrahydrophthalic anhydride, with a weight ratio of 5:1.

[0077] The specific implementation of the method for preparing the solder resist dry film is the same as that of Example 1.

[0078] The solder resist dry film is applied to a PCB board. The specific method is as follows: one side of the light-curing and heat-curing resin composition of the solder resist dry film is pressed against the surface of the PCB board, exposed using a 365nm wavelength ultraviolet light exposure machine, removing the carrier film, developing in a 1wt% sodium carbonate aqueous solution at 30°C, and then heat curing in a 160°C oven for 60 minutes.

[0079] Example 5

[0080] Example 5 of the present invention provides a solder mask dry film, and its specific implementation method is the same as that of Example 3, except that the anhydride-modified epoxy acrylic resin with an acid value of 105 mg KOH / g is obtained by reacting epoxy acrylic resin, acid anhydride, triethylamine, and hydroquinone at 80°C; the epoxy acrylic resin has a viscosity of 40,000-60,000 cps at 25°C and is purchased from Jinan Quanxing New Materials Co., Ltd.; the acid anhydride is dehydrated malic anhydride and methyltetrahydrophthalic anhydride, with a weight ratio of 5:1.

[0081] The specific implementation of the method for preparing the solder resist dry film is the same as that of Example 1.

[0082] The solder resist dry film is applied to a PCB board. The specific method is as follows: one side of the light-curing and heat-curing resin composition of the solder resist dry film is pressed against the surface of the PCB board, exposed using a 365nm wavelength ultraviolet light exposure machine, removing the carrier film, developing in a 1wt% sodium carbonate aqueous solution at 30°C, and then heat curing in a 160°C oven for 60 minutes.

[0083] Performance Evaluation

[0084] 1. Viscosity stability: The viscosities of the light-curable and heat-curable resin compositions obtained in Examples 1-5 were each tested 10 times in parallel using a grid tube viscometer, and the average values ​​were taken. After 10 days, the viscosities were again tested 10 times in parallel, and the average values ​​were taken again. The rate of change of the average viscosity was calculated. A rate of change of ≤10% was considered excellent; otherwise, it was considered poor.

[0085] 2. Chemical nickel-palladium-gold resistance: PCB boards prepared with the solder mask dry films of Examples 1-5 were treated with a chemical nickel-palladium-gold solution. After treatment, the nickel plating had a thickness of 3 μm and the gold plating had a thickness of 0.3 μm. The boards were then washed and dried. 3M 600 tape was used to evaluate the chemical nickel-palladium-gold resistance. The evaluation method was as follows: Level 1: no peeling; Level 2: minor peeling; Level 3: partial and large-scale peeling. The higher the level, the worse the chemical nickel-palladium-gold resistance.

[0086] Table 1

[0087]

Claims

1. A solder resist dry film, characterized in that: The raw materials for the preparation include, by weight, 15-40 parts of anhydride-modified epoxy acrylic resin, 20-30 parts of acrylate, 10-20 parts of curing agent, 1-10 parts of photoinitiator, and 2-40 parts of solvent; The raw materials for preparing the anhydride-modified epoxy acrylic resin include epoxy acrylic resin, acid anhydride, triethylamine, and hydroquinone. The viscosity of the epoxy acrylic resin at 25° C. is 5000-7000 mPa.s. The anhydride in the anhydride-modified epoxy acrylic resin is dehydrated malic anhydride and / or methyltetrahydrophthalic anhydride; The acid value of the anhydride-modified epoxy acrylic resin is 100-110 mg KOH / g.

2. The solder resist dry film according to claim 1, wherein: The number of carbon atoms of the acrylic acid ester is 10-15.

3. The solder resist dry film according to claim 1, wherein: The raw materials for preparing the solder resist dry film further include 20-30 parts by weight of silicate powder.

4. The solder resist dry film according to claim 3, wherein: The silicate powder is bentonite and / or talc.

5. The solder resist dry film according to claim 1, wherein: The solvent is an amide solvent.

6. The solder resist dry film according to claim 1, wherein: The curing agent contains one or more of an epoxy group, an isocyanate group, a cyclic ether group, an oxetane group, and a carbon-carbon double bond.

7. Use of the solder resist dry film according to any one of claims 1 to 6 in a PCB board.

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