A high flame retardant resin composition, dry film and its application in mini LED board

Abstract

The application discloses a kind of high flame-retardant resin compositions, preparation raw materials include: 50-100 parts resin, 10-30 parts active monomer, 1-5 parts curing agent, 1-10 parts flame retardant, 1-5 parts photo initiator, 20-50 parts solvent by mass fraction.The dry film of the resin composition prepared by the solder mask, the preparation raw materials of the solder mask also include 50-200 parts titanium dioxide by mass fraction.The dry film of the solder mask prepared by the application has good flame retardancy, excellent heat resistance and chemical reagent resistance, is halogen-free, green and environmentally friendly, is used for Mini LED white solder mask dry film, the surface of solder mask layer is uniform and smooth, and the reflectivity is greater than 85% or more.

Description

Technical Field

[0001] This invention relates to the field of G03F technology, specifically to a highly flame-retardant resin composition, a dry film, and its application in Mini LED panels. Background Technology

[0002] Mini LED chips range in size from 50 to 200 μm. They consist of a Mini LED pixel array and a driving circuit, with a pixel center-to-center spacing of 0.3-1.5 mm. Mini LED display products have begun to be used in ultra-large screen high-definition displays, such as monitoring and command, high-definition broadcasting, high-end cinemas, medical diagnostics, advertising displays, conferences and exhibitions, office displays, virtual reality and other commercial fields. The main function of solder mask is to prevent bridging between conductors and pads. It also has anti-corrosion, moisture-proof and mildew-proof functions. Therefore, the quality of solder mask is related to the reliability and service life of PCB.

[0003] CN109957283B discloses a highly flame-retardant solder resist ink, the formulation of which includes: acrylate compounds with carboxyl groups, phosphorus-containing acrylates, nitrogen-containing acrylates, silicone-containing acrylates, epoxy resin, epoxy resin curing agent, photoinitiator, and other additives. The solder resist ink coating disclosed in this patent can successfully pass the UL94V-0 test and has excellent flame retardancy, adhesion, and photosensitivity.

[0004] CN102286228B discloses a method for preparing a high-temperature resistant, halogen-free, flame-retardant UV-curable solder resist ink. This patent introduces a radiation-curable nitrogen-containing phosphide as a halogen-free flame retardant into the solder resist ink formulation. It uses a compound of β-hydroxyethyl acrylate-modified melamine-formaldehyde resin and acrylate-modified phenolic epoxy resin as the main resin, along with active monomers, photoinitiators, color pastes, fillers, and additives. The process involves mixing, dispersing, grinding, and filtering to prepare the high-temperature resistant, halogen-free, flame-retardant UV-curable solder resist ink. The solder resist ink disclosed in this patent features high temperature resistance, high flame retardancy, high hardness, and is halogen-free.

[0005] However, the solder resist ink disclosed in the above patent consumes a large amount of water and chemicals, has a long processing time, lacks flexibility, and the prepared solder resist layer has poor flatness, making it unsuitable for Mini LED. Summary of the Invention

[0006] To address the aforementioned problems, this invention discloses a highly flame-retardant resin composition, the raw materials of which, by weight, include: 50-100 parts resin, 10-30 parts active monomer, 1-5 parts curing agent, 1-10 parts flame retardant, 1-5 parts photoinitiator, and 20-50 parts solvent.

[0007] In one embodiment, the resin is selected from one or more of epoxy resin, acrylic resin, phenolic resin, and polystyrene resin.

[0008] Preferably, the resin is selected from epoxy resin and phenolic resin in a mass ratio of (1-5):1.

[0009] More preferably, the mass ratio of the epoxy resin to the phenolic resin is 3:1.

[0010] In one embodiment, the epoxy resin is a graphene-modified epoxy resin.

[0011] Preferably, the graphene-modified epoxy resin is a phosphorus-modified graphene oxide epoxy resin.

[0012] In one embodiment, the raw materials for preparing the phosphorus-modified graphene oxide epoxy resin include: graphene, a phosphorus-containing reducing agent, and an epoxy resin matrix.

[0013] Preferably, the graphene is prepared by a redox method.

[0014] Preferably, the phosphorus-containing reducing agent is selected from one or more of phosphorous acid and hypophosphite.

[0015] More preferably, the phosphorus-containing reducing agent is hypophosphite.

[0016] Preferably, the epoxy resin matrix is ​​selected from one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyphenol type glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, and glycidyl ester type epoxy resin.

[0017] More preferably, the epoxy resin matrix is ​​a polyphenolic glycidyl ether epoxy resin.

[0018] More preferably, the polyphenolic glycidyl ether epoxy resin is bisphenol A glycidyl ether epoxy resin, CAS No.: 61788-97-4.

[0019] Preferably, the mass ratio of the graphene, phosphorus-containing reducing agent, and epoxy resin matrix is ​​1:(0.5-1):(100-1100).

[0020] More preferably, the mass ratio of the graphene, phosphorus-containing reducing agent, and epoxy resin matrix is ​​1:1:300.

[0021] The undisclosed portions of the phosphorus-modified graphene oxide epoxy resin described in this application can be conventionally selected by those skilled in the art.

[0022] This application uses a redox method to prepare graphene. Active oxygen atoms combine with π electrons within the graphite sheets to form oxygen-containing functional groups such as hydroxyl, carboxyl, and epoxy groups. Under the action of the strong reducing agent hypophosphite, a redox reaction occurs, introducing phosphorus atoms with flame-retardant properties into the graphene. By combining the phosphorus-modified graphene oxide with an epoxy resin matrix, the flame retardancy and mechanical properties of the epoxy resin matrix can be improved. The applicant believes the possible reason is that phosphorus groups have less steric hindrance compared to epoxy and carbonyl groups. Introducing phosphorus groups to replace sterically hindered groups such as epoxy and carbonyl groups can improve the compatibility of the components in the system, resulting in better dispersibility, stronger stability, and improved mechanical and flame-retardant properties.

[0023] In one embodiment, the phenolic resin is a furan-modified phenolic resin.

[0024] Preferably, the raw materials for preparing the furan-modified phenolic resin include: furfuryl alcohol, phenolic resin matrix, and catalyst.

[0025] Preferably, the phenolic resin matrix is ​​prepared from formaldehyde and phenol in a molar ratio of (0.7-0.8):1, with an average molecular weight of 500-800.

[0026] Preferably, the catalyst is selected from one or more of sodium hydroxide, potassium carbonate, sodium carbonate, and potassium hydroxide.

[0027] More preferably, the catalyst is selected from sodium hydroxide.

[0028] Preferably, the mass ratio of furfuryl alcohol, phenolic resin matrix, and catalyst is 1:(1-3):(0.01-0.2).

[0029] More preferably, the mass ratio of furfuryl alcohol, phenolic resin matrix, and catalyst is 1:1.1:0.05.

[0030] The undisclosed portions of the furan-modified phenolic resin described in this application can be conventionally selected by those skilled in the art.

[0031] In one embodiment, the curing agent is an aliphatic amine curing agent.

[0032] Preferably, the aliphatic amine curing agent is one or more of the following: methylene dicyclohexaneamine, triethylamine, ethylenediamine, hexamethylenediamine, divinyltriamine, 1,2, diaminocyclohexane, tetraethylenepentamine, diallyltriamine, dimethylaminopropylamine, isophorone diamine, aminoethylpiperazine, diethylenetriamine, and diethylaminopropylamine.

[0033] More preferably, the aliphatic amine curing agent is diethylaminopropylamine.

[0034] The furan ring contains double bonds and is a conjugated system. Under the catalysis of sodium hydroxide, it readily undergoes addition condensation polymerization, introducing these bonds into phenolic resins and thereby improving their alkali resistance and heat resistance. During extensive experimentation, the applicant unexpectedly discovered that simultaneously adding phosphorus-modified graphene oxide epoxy resin and furan-modified phenolic resin in a mass ratio of (1-5):1 further improves the system's mechanical properties, flame retardancy, heat resistance, and chemical resistance. The applicant believes the likely reason is that, under the action of a curing agent, the epoxy resin and furan-phenolic resin undergo a multi-component cross-linking reaction, introducing flame-retardant amine groups while simultaneously increasing the degree of cross-linking and reducing the system's porosity, thus enhancing the overall performance of the system.

[0035] In one embodiment, the active monomer is selected from one or more of trimethylolpropane triacrylate, triethylene glycol acrylate, β-hydroxyethyl methacrylate, tripropylene glycol diacrylate, pentaerythritol triacrylate, hexanediol diacrylate, dipropylene glycol diacrylate, and ethoxylated trimethylolpropane triacrylate.

[0036] Preferably, the active monomer is hexanediol diacrylate.

[0037] In one embodiment, the flame retardant is selected from one or more of aluminum hydroxide, magnesium hydroxide, antimony trioxide, colloidal antimony pentoxide, and organosilicon flame retardants.

[0038] Preferably, the flame retardant is aluminum hydroxide and an organosilicon flame retardant in a mass ratio of (5-10):1.

[0039] More preferably, the mass ratio of aluminum hydroxide to organosilicon flame retardant is 7:1.

[0040] During extensive experimentation, the applicant creatively discovered that the simultaneous addition of aluminum hydroxide and organosilicon flame retardants significantly improves the flame retardant performance of the system. The applicant believes this is because aluminum hydroxide has a relatively low dehydration endothermic temperature, approximately 235–350°C, resulting in a significant flame-retardant effect at the initial stage of combustion in plastics. Meanwhile, organosilicon flame retardants can undergo cross-linking reactions with resins, restricting the mobility of flame-retardant groups in the system and preventing them from migrating to the polymer surface and being consumed by combustion, thus failing to achieve sustained flame retardant performance. The combined addition of both ensures a significant flame-retardant effect throughout the entire combustion process while reducing the amount of flame retardant required and lowering costs.

[0041] In one embodiment, the photoinitiator is a photoinitiator capable of inducing double bond coupling, selected from benzoin derivatives, acetophenone derivatives, benzophenone derivatives, anthraquinone derivatives, α-aminoacetophenone derivatives, acylphosphine oxide derivatives, oxime esters, etc.

[0042] Preferably, the photoinitiator is 2,4,6,(trimethylbenzoyl)diphenylphosphine oxide.

[0043] The CAS number for the 2,4,6,(trimethylbenzoyl)diphenylphosphine oxide is 75980-60-8.

[0044] In one embodiment, the solvent is selected from solvents such as ketones, alcohols, esters, ethers, benzenes, and petroleum solvents.

[0045] Preferably, the solvent is an ester solvent.

[0046] More preferably, the solvent is ethyl acetate.

[0047] The second aspect of the present invention discloses a method for preparing a solder resist dry film prepared from the resin composition, wherein the raw materials for preparing the solder resist dry film further include 50-200 parts of titanium dioxide by weight.

[0048] The method for preparing the solder resist dry film is as follows:

[0049] S1: Mix the raw materials for preparing the solder resist dry film to obtain the solder resist liquid.

[0050] S2: Vacuum lamination: Temperature 50-80℃, Pressure 0.3-0.8MPa, Vacuum time 20-40s, Pressing time 20-40s

[0051] S3: Exposure: 1200-1600mJ / cm 2 Levels 10-15 / 21

[0052] S4: Development: 0.8-1.5% Na2CO3, 25-35℃, 40-80s, pressure 0.5-1.5Kg / cm² 2

[0053] S5: Baking: 150-180℃, 45-80min

[0054] The solder resist dry film disclosed in this invention is applied to Mini LED boards.

[0055] Beneficial effects:

[0056] 1. By adding phosphorus-modified graphene oxide epoxy resin and furan-modified phenolic resin, the mechanical properties, flame retardancy, heat resistance and chemical resistance of the system can be improved.

[0057] 2. By adding aluminum hydroxide and organosilicon flame retardants, this invention can ensure a significant flame retardant effect throughout the entire combustion process while reducing the amount of flame retardant added and the cost.

[0058] 3. The solder resist dry film prepared by this invention has good flame retardancy, excellent heat resistance and chemical reagent resistance, is halogen-free, green and environmentally friendly, and can be used as a solder resist dry film for Mini LEDs. The surface of the solder resist layer is uniform and flat, and the reflectivity is greater than 85%. Detailed Implementation

[0059] Example 1

[0060] Example 1 of the present invention discloses a highly flame-retardant resin composition, the raw materials for which, by mass, are: 50 parts resin, 30 parts hexanediol diacrylate, 1 part flame retardant, 1 part 2,4,6,(trimethylbenzoyl)diphenylphosphine oxide, and 20 parts ethyl acetate.

[0061] The resin is selected from epoxy resin and phenolic resin in a mass ratio of 1:1.

[0062] The epoxy resin is a phosphorus-modified graphene oxide epoxy resin.

[0063] The raw materials for preparing the phosphorus-modified graphene oxide epoxy resin include: graphene, phosphorus-containing reducing agent, and epoxy resin matrix.

[0064] The graphene was prepared using a redox method.

[0065] The phosphorus-containing reducing agent is hypophosphite.

[0066] The epoxy resin matrix is ​​a polyphenolic glycidyl ether epoxy resin.

[0067] The polyphenolic glycidyl ether epoxy resin is bisphenol A glycidyl ether epoxy resin, purchased from Nantong Runfeng Petrochemical Co., Ltd., CAS No.: 61788-97-4.

[0068] The mass ratio of graphene, hypophosphite, and bisphenol A glycidyl ether epoxy resin is 1:1:300.

[0069] The undisclosed portions of the phosphorus-modified graphene oxide epoxy resin described in this application can be conventionally selected by those skilled in the art.

[0070] The phenolic resin is a furan-modified phenolic resin.

[0071] The raw materials for preparing the furan-modified phenolic resin include: furfuryl alcohol, phenolic resin matrix, and catalyst.

[0072] The phenolic resin matrix is ​​prepared from formaldehyde and phenol in a molar ratio of 0.75:1, with an average molecular weight of 500-800.

[0073] The catalyst is selected from sodium hydroxide.

[0074] The mass ratio of furfuryl alcohol, phenolic resin matrix, and catalyst is 1:1.1:0.05.

[0075] The undisclosed portions of the furan-modified phenolic resin described in this application can be conventionally selected by those skilled in the art.

[0076] The flame retardant is an aluminum hydroxide and an organosilicon flame retardant in a mass ratio of 5:1.

[0077] The organosilicon flame retardant was purchased from Guangzhou Yinuo Chemical Technology Co., Ltd., and its model number is FCA-107.

[0078] The second aspect of Embodiment 1 of the present invention discloses a solder resist dry film prepared from the resin composition, wherein, by weight, the raw materials for preparing the solder resist dry film further include 200 parts of titanium dioxide.

[0079] Embodiment 1 of the present invention also discloses a method for preparing the solder resist dry film, the steps of which are as follows:

[0080] S1: Mix the raw materials for preparing the solder resist dry film to obtain the solder resist liquid.

[0081] S2: Vacuum pressing: Temperature 50℃, pressure 0.3MPa, vacuum time 40s, pressing time 40s.

[0082] S3: Exposure: 1200mJ / cm 2 Levels 10-15 / 21.

[0083] S4: Development: 0.8% Na2CO3, 25℃, 80s, pressure 1.5Kg / cm 2 .

[0084] S5: Baking: 150℃, 80min.

[0085] Example 2

[0086] Example 2 of the present invention discloses a highly flame-retardant resin composition, which, by weight, comprises: 100 parts resin, 10 parts hexanediol diacrylate, 10 parts flame retardant, 5 parts 2,4,6,(trimethylbenzoyl)diphenylphosphine oxide, and 50 parts ethyl acetate.

[0087] The resin is selected from epoxy resin and phenolic resin in a mass ratio of 5:1.

[0088] The epoxy resin and phenolic resin are the same as in Example 1.

[0089] The flame retardant is an aluminum hydroxide and an organosilicon flame retardant in a mass ratio of 10:1.

[0090] The organosilicon flame retardant was purchased from Guangzhou Yinuo Chemical Technology Co., Ltd., and its model number is FCA-107.

[0091] The second aspect of Embodiment 2 of the present invention discloses a solder resist dry film prepared from the resin composition, wherein, by weight, the raw materials for preparing the solder resist dry film further include 50 parts of titanium dioxide.

[0092] Embodiment 2 of the present invention also discloses a method for preparing the solder resist dry film, the steps of which are as follows:

[0093] S1: Mix the raw materials for preparing the solder resist dry film to obtain the solder resist liquid.

[0094] S2: Vacuum pressing: Temperature 80℃, pressure 0.8MPa, vacuum time 20s, pressing time 20s.

[0095] S3: Exposure: 1600mJ / cm 2 Levels 10-15 / 21

[0096] S4: Development: 1.5% Na2CO3, 35℃, 40s, pressure 0.5Kg / cm 2 .

[0097] S5: Baking: 180℃, 45min.

[0098] Example 3

[0099] Example 3 of the present invention discloses a highly flame-retardant resin composition, which, by weight, comprises the following raw materials: 78 parts resin, 23 parts hexanediol diacrylate, 8 parts flame retardant, 2.5 parts 2,4,6,(trimethylbenzoyl)diphenylphosphine oxide, and 45 parts ethyl acetate.

[0100] The resin is selected from epoxy resin and phenolic resin in a mass ratio of 3:1.

[0101] The epoxy resin and phenolic resin are the same as in Example 1.

[0102] The flame retardant is an aluminum hydroxide and an organosilicon flame retardant in a mass ratio of 7:1.

[0103] The organosilicon flame retardant was purchased from Guangzhou Yinuo Chemical Technology Co., Ltd., and its model number is FCA-107.

[0104] The second aspect of Embodiment 3 of the present invention discloses a solder resist dry film prepared from the resin composition, wherein, by weight, the raw materials for preparing the solder resist dry film further include 160 parts of titanium dioxide.

[0105] Embodiment 3 of the present invention also discloses a method for preparing the solder resist dry film, the steps of which are as follows:

[0106] S1: Mix the raw materials for preparing the solder resist dry film to obtain the solder resist liquid.

[0107] S2: Vacuum pressing: Temperature 75℃, pressure 0.5MPa, vacuum time 25s, pressing time 30s.

[0108] S3: Exposure: 1500mJ / cm 2 Levels 10-15 / 21.

[0109] S4: Development: 1% Na2CO3, 30℃, 60s, pressure 0.6Kg / cm 2 .

[0110] S5: Baking: 155℃, 60min.

[0111] Example 4

[0112] The resin is 78 parts of furan-modified phenolic resin, and the rest is the same as in Example 3.

[0113] Example 5

[0114] The resin is selected from epoxy resin and phenolic resin in a mass ratio of 10:1, and the rest is the same as in Example 3.

[0115] Example 6

[0116] The flame retardant is 8 parts magnesium hydroxide, and the rest is the same as in Example 3.

[0117] Performance testing:

[0118] 1. Reflectivity test: The reflectivity was tested after the SMT nitrogen oven was run through three times at a wavelength of 600nm. The results are recorded in Table 1 below.

[0119] 2. Flatness test:

[0120] a) Lamination: Under vacuum laminator, 75°C, vacuum for 25s, and lamination for 30s.

[0121] Leveling: Pressure 0.6 kg / cm 2 Leveling time: 60 seconds.

[0122] After the dry film is bonded to the PCB surface, it is photocured and heat-cured at 155℃ for 60 minutes using a DI exposure machine with 1500mJ.

[0123] b) The total thickness error between the copper surface and the substrate surface was measured by cross-sectioning, and the results are recorded in Table 1 below.

[0124] 3. Acid resistance test: Immerse in 10% sulfuric acid for 10 minutes. If there is no abnormality, it is qualified; otherwise, it is unqualified. The results are recorded in Table 1 below.

[0125] 4. Alkali resistance test: Immerse in 10% sodium hydroxide for 10 minutes. If there is no abnormality, it is qualified; otherwise, it is unqualified. The results are recorded in Table 1 below.

[0126] 5. Flame retardant performance test: A specimen with a length of 125 mm and a width of 12.5 mm was cut from the evaluation substrate (cured prepreg) and a combustion test was conducted according to "Plastic Materials Flammability Test - UL94". The results are recorded in Table 1.

[0127] 6. Adhesion test: According to the test method of JJSD0202, the cured film is cut into 1mm×1mm squares and a peel test is performed using 3M adhesive tape.

[0128] 7. Thermal shock test: 500 cycles are performed from -35℃ to +135℃. A) No abnormality, B) Abnormality. The results are recorded in Table 1 below.

[0129] 8. Hardness test: The test shall be conducted in accordance with GB / T6739-2006 "Determination of Hardness of Paints and Varnishes by Pencil Method" and the results shall be recorded in Table 1 below.

[0130] Table 1

[0131]

Claims

1. A highly flame-retardant resin composition, characterized in that, The raw materials for preparation, by weight, include: 50-100 parts resin, 10-30 parts active monomer, 1-5 parts curing agent, 1-10 parts flame retardant, 1-5 parts photoinitiator, and 20-50 parts solvent. The resin is selected from epoxy resin and phenolic resin, with a mass ratio of (1-5):1; The epoxy resin is a phosphorus-modified graphene oxide epoxy resin. The phenolic resin is a furan-modified phenolic resin; The curing agent is an aliphatic amine curing agent; The flame retardant is aluminum hydroxide and organosilicon flame retardant in a mass ratio of (5-10):1; The active monomer is selected from one or more of the following: trimethylolpropane triacrylate, triethylene glycol acrylate, β-hydroxyethyl methacrylate, tripropylene glycol diacrylate, pentaerythritol triacrylate, hexanediol diacrylate, tripropylene glycol diacrylate, and ethoxylated trimethylolpropane triacrylate.

2. The resin composition according to claim 1, characterized in that, The photoinitiator is selected from one of the following: benzoin, acetophenone, benzophenone, anthraquinone, α-aminoacetophenone, acylphosphine oxide, and oxime ester.

3. A solder resist dry film prepared according to the resin composition according to claim 1 or 2, characterized in that, The raw materials for preparing the solder resist dry film also include 50-200 parts of titanium dioxide by weight.

4. A method for preparing a solder resist dry film according to claim 3, characterized in that, Includes the following steps: S1: Mix the raw materials for preparing the solder resist dry film to obtain the solder resist liquid; S2: Vacuum pressing; S3: Exposure; S4: Development; S5: Baking.

5. An application of the solder resist dry film according to claim 4, characterized in that, The solder resist dry film is used with Mini LED boards.

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