Flexible epoxy plastic packaging material, preparation method and application thereof

Abstract

This invention relates to the field of epoxy resin encapsulation materials technology, and discloses a flexible epoxy molding compound, its preparation method, and its application. The method includes: (1) reacting a chain extender, polydiol, and an anhydride curing agent to obtain a polydiol anhydride prepolymer; (2) mixing the polydiol anhydride prepolymer, an epoxy compound, an antioxidant, a curing accelerator, an optional release agent, and an optional tackifier; wherein the epoxy compound is triglycidyl isocyanurate and bisphenol A type epoxy resin, the weight ratio of the triglycidyl isocyanurate to the bisphenol A type epoxy resin is 1:0.1-1.5; the equivalent ratio of the epoxy groups of the anhydride curing agent to the epoxy compound is 0.7-1.2:1; the molar ratio of the chain extender, polydiol, to the anhydride curing agent is 0.04-0.5:1; and the molecular weight of the chain extender, polydiol, is 400-2000. This flexible epoxy molding compound has both low curing shrinkage and low internal stress. When applied to chip packaging and cured, it also has high light transmittance, temperature and humidity resistance, and resistance to high and low temperature impacts.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin encapsulation materials technology, specifically to a flexible epoxy molding compound, its preparation method, and its application. Background Technology

[0002] With the miniaturization and thinning of electronic components, the market demand for epoxy molding compounds with low shrinkage, low stress, and impact resistance is increasing. Existing epoxy molding compounds on the market are all rigid materials after curing, resulting in high internal stress. This limits their application in large-size packaging applications with high requirements for high temperature and high temperature impact, and also causes difficulties in subsequent cutting. Furthermore, high shrinkage after curing can lead to insufficient adhesion between the internal components and the substrate, causing delamination and lead breakage. While silicone materials offer good flexibility and weather resistance, their high water absorption rate can cause chip oxidation, discoloration, or blackening, limiting their use in electronic packaging. To reduce the shrinkage of cured materials, a common method is to increase the proportion of inorganic fillers. However, increasing the amount of inorganic fillers significantly reduces the light transmittance and photothermal aging resistance of the cured material. Therefore, solving the problem of achieving low curing shrinkage and low internal stress in epoxy molding compounds while simultaneously maintaining high light transmittance, temperature and humidity resistance, and high and low temperature impact resistance after curing has become an important research direction. Summary of the Invention

[0003] The purpose of this invention is to overcome the problems existing in the prior art and provide a flexible epoxy molding compound. This flexible epoxy molding compound has both low curing shrinkage and low internal stress, and when applied to chip packaging and curing, it also has high light transmittance, temperature and humidity resistance, and high and low temperature impact resistance.

[0004] To achieve the above objectives, the present invention provides a method for preparing a flexible epoxy molding compound, the method comprising:

[0005] (1) The chain extender polydiol and the acid anhydride curing agent are reacted to obtain polydiol acid anhydride prepolymer;

[0006] (2) Mix the polydiol anhydride prepolymer, triglycidyl isocyanate, bisphenol A epoxy resin, antioxidant, curing accelerator, optional release agent and optional tackifier.

[0007] The epoxy compound is triglycidyl isocyanurate and bisphenol A type epoxy resin, wherein the weight ratio of triglycidyl isocyanurate to bisphenol A type epoxy resin is 1:0.1-1.5.

[0008] The equivalent ratio of the anhydride curing agent to the epoxy group of the epoxy compound is 0.7-1.2:1;

[0009] The molar ratio of the chain extender polydiol to the anhydride curing agent is 0.04-0.5:1;

[0010] The chain extender, polydiol, has a molecular weight of 400-2000.

[0011] Preferably, in step (1), the reaction conditions include: a temperature of 20-90°C and a time of 10-30 min.

[0012] Preferably, in step (2), the mixing conditions include: a temperature of 20-100℃ and a time of 10-30 min.

[0013] Preferably, the total weight ratio of the chain extender (polydiol), the anhydride curing agent, the triglycidyl isocyanate, and the bisphenol A epoxy resin to the antioxidant is 100:2-6; and / or

[0014] The total weight ratio of the chain extender (polydiol), acid anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the curing accelerator is 100:0.1-0.8; and / or

[0015] The total weight ratio of the chain extender (polydiol), acid anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the release agent is 100:0-5; and / or

[0016] The total weight ratio of the chain extender polydiol, acid anhydride curing agent, triglycidyl isocyanate and bisphenol A epoxy resin to the weight of the tackifier is 100:0-2.

[0017] Preferably, the epoxy equivalent of the bisphenol A type epoxy resin is 90-1000 g / eq; and / or

[0018] The molecular weight of the anhydride curing agent is 100-500.

[0019] Preferably, the oxidant is selected from one or more of amine-based antioxidants, phosphorus-based antioxidants, and phenolic antioxidants; and / or

[0020] The curing accelerator is selected from one or more of amine accelerators, phenolic accelerators, imidazole accelerators, boron trifluoride complexes, organometallic salts, and phosphine accelerators.

[0021] Preferably, the release agent is a natural wax and / or a synthetic wax; and / or

[0022] The tackifier is selected from one or more of 4,4'-dithiodimorpholine, bis-(γ-triethoxysilylpropyl)tetrasulfide, bis-[3-(triethoxysilyl)propyl]-disulfide, 3-mercaptopropyltrimethoxysilane, methacryloyloxypropylmethyldimethoxysilane, and 3-[(2,3)-epoxypropoxy]propylmethyldimethoxysilane.

[0023] A second aspect of the present invention provides a flexible epoxy molding compound prepared by the above method.

[0024] A third aspect of the present invention provides the application of the above-mentioned flexible epoxy molding compound in electronic component packaging materials.

[0025] A fourth aspect of the present invention provides a method for preparing a flexible epoxy molding compound, the method comprising: injection molding the above-mentioned flexible epoxy molding compound into a mold, and then curing it;

[0026] Preferably, the injection molding conditions include: a temperature of 120-185℃, a time of 100-300s, and a pressure of <20MPa; and / or

[0027] The curing conditions include a temperature of 140-180℃ and a time of 2-8 hours.

[0028] Compared with existing technologies, the method for preparing flexible epoxy molding compounds described in this invention involves a pre-polyesterification reaction between an anhydride curing agent and a chain extender of a specific molecular weight, polydiol, to obtain a modified anhydride curing agent with a long-chain structure. This increases the flexibility of the material on the one hand, and reduces the crosslinking density between the anhydride curing agent and epoxy resin due to the reduction of active groups in the anhydride curing agent, thereby reducing the rigidity of the cured epoxy molding compound. This results in a flexible epoxy resin molding compound product with low shrinkage and low stress, thus increasing its adhesion to the substrate. Simultaneously, the addition of antioxidants can improve the curing... The photothermal stability of the compound is improved, inhibiting yellowing caused by aging. The addition of a curing accelerator can further improve the degree of reaction between the substances, increase the reaction efficiency, thereby reducing the coefficient of linear expansion and water absorption. As a result, the final flexible epoxy molding compound has both low curing shrinkage and low internal stress. When applied to chip packaging after curing, it also has high light transmittance, temperature and humidity resistance, and resistance to high and low temperature impacts. The light transmittance of the cured flexible epoxy molding compound is over 90%, the warpage is less than 0.1 mm, the tensile strength is greater than 80 MPa, and the elongation at break is greater than 10%. Detailed Implementation

[0029] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0030] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0031] This invention provides a method for preparing flexible epoxy molding compound, the method comprising:

[0032] (1) The chain extender polydiol and the acid anhydride curing agent are reacted to obtain polydiol acid anhydride prepolymer;

[0033] (2) Mix the polydiol anhydride prepolymer, epoxy, antioxidant, curing accelerator, optional release agent and optional tackifier;

[0034] The epoxy compound is triglycidyl isocyanurate and bisphenol A type epoxy resin, wherein the weight ratio of triglycidyl isocyanurate to bisphenol A type epoxy resin is 1:0.1-1.5.

[0035] The equivalent ratio of the anhydride curing agent to the epoxy group of the epoxy compound is 0.7-1.2:1;

[0036] The molar ratio of the chain extender polydiol to the anhydride curing agent is 0.04-0.5:1;

[0037] The chain extender, polydiol, has a molecular weight of 400-2000.

[0038] In the method described in this invention, in step (1), a pre-polyesterification reaction is first carried out using a chain extender polydiol of a specific molecular weight and a specific amount of anhydride curing agent to obtain a modified anhydride curing agent with a long chain structure. This avoids the problem of insufficient addition of chain extender polydiol, which fails to achieve the effect of toughening and softening, and also avoids the problem of excessive addition causing low crosslinking density or failure to cure the cured product. In step (2), the addition of antioxidant can improve the photothermal stability of the cured product and inhibit its yellowing due to aging. The addition of curing accelerator can further improve the reaction between the various substances. The process increases reaction efficiency, thereby reducing the coefficient of linear expansion and water absorption. Simultaneously, by using specific amounts and proportions of chain extender (polydiol), acid anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin, the final flexible epoxy molding compound exhibits both low curing shrinkage and low internal stress. When applied to chip packaging and cured, it also possesses high light transmittance, resistance to temperature and humidity, and resistance to high and low temperature impacts. The cured flexible epoxy molding compound has a light transmittance of over 90%, a warpage of less than 0.1 mm, a tensile strength greater than 80 MPa, and an elongation at break greater than 10%.

[0039] In this invention, "the equivalent ratio of the epoxy groups of the anhydride curing agent to the epoxy group of the epoxy compound" refers to the equivalent ratio of the molar amount of the anhydride curing agent to the equivalent ratio of the epoxy groups of the epoxy compound (i.e., triglycidyl isocyanate and bisphenol A type epoxy resin). This ratio is calculated based on (weight of the anhydride curing agent / molecular weight of the anhydride curing agent) / (weight of the epoxy compound / epoxy equivalent of the epoxy compound). This ratio is 0.7-1.2:1, for example, it can be 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.1:1, or 1.2:1. When the ratio is less than 0.7, the curing efficiency is low or complete curing is impossible, and the glass transition temperature is low. When the ratio is greater than 1.2, the moisture resistance of the cured product decreases.

[0040] In this invention, "epoxy equivalent" refers to "the mass of epoxy resin per mole of epoxy group, expressed in grams per equivalent".

[0041] In a preferred embodiment, in order to improve the chemical stability of the polydiol anhydride prepolymer, the reaction conditions in step (1) include: a temperature of 20-90°C and a time of 10-30 min.

[0042] In a preferred embodiment, the mixing conditions in step (2) include a temperature of 20-100°C and a time of 10-30 min.

[0043] In a preferred embodiment, the total weight ratio of the chain extender polydiol, the acid anhydride curing agent, the triglycidyl isocyanate and the bisphenol A epoxy resin to the weight of the antioxidant is 100:2-6; preferably 100:3-5.

[0044] In a preferred embodiment, the weight ratio of the total weight of the chain extender polydiol, the acid anhydride curing agent, the triglycidyl isocyanate and the bisphenol A epoxy resin to the weight of the curing accelerator is 100:0.1-0.8; preferably 100:0.2-0.6.

[0045] In a preferred embodiment, the total weight ratio of the chain extender polydiol, the acid anhydride curing agent, the triglycidyl isocyanate and the bisphenol A epoxy resin to the weight of the release agent is 100:0-5; preferably 100:0.5-4.

[0046] In a preferred embodiment, the total weight ratio of the chain extender polydiol, the acid anhydride curing agent, the triglycidyl isocyanate and the bisphenol A epoxy resin to the weight of the tackifier is 100:0-2; preferably 100:0.4-1.5.

[0047] In this invention, there are no special requirements for the chain extender polydiol, as long as the molecular weight is between 400 and 2000; in a preferred embodiment, the chain extender polydiol is selected from one or more of polyethylene glycol, polypropylene glycol and polybutanediol; more preferably, the chain extender polydiol is selected from one or more of polyethylene glycol 600, polypropylene glycol 400 and polypropylene glycol 1025.

[0048] In this invention, there are no special requirements for the anhydride curing agent; any commonly used anhydride curing agent in the art is acceptable. In a preferred embodiment, the molecular weight of the anhydride curing agent is 100-500. Specifically, the anhydride curing agent is selected from one or more of tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0049] In this invention, there are no special requirements for the bisphenol A type epoxy resin, and any commonly used bisphenol A type epoxy resin in the art is acceptable; in a preferred embodiment, the epoxy equivalent of the bisphenol A type epoxy resin is 90-1000 g / eq; specifically, the bisphenol A type epoxy resin is one or more of bisphenol A type epoxy resin E20, bisphenol A type epoxy resin E51, and bisphenol A type epoxy resin NPES-901.

[0050] In a preferred embodiment, the oxidant is selected from one or more of amine antioxidants, phosphorus antioxidants, and phenolic antioxidants; preferably, the antioxidant is a phosphorus antioxidant and / or a phenolic antioxidant.

[0051] In a specific embodiment, the amine antioxidant is selected from bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 2,2,6,6-tetramethyl-4-diethylpiperidinyl dione methacrylate, tetra(2,2,6,6-tetramethyl-4-piperidinyl) ester of 1,2,3,4-butanetetracarboxylate, bis(1-undecyloxy-2,2,6,6-tetramethylpiperidin-4-yl) carbonate, 2-methyl-2-acrylate-1,2,2,4,6-pentamethyl-4-piperidinyl ester, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, [(3,5-di-tert-butyl-4-hydroxyphenyl)methyl]butylmalonate di(1,2,2,6,6-pentamethyl-4-piperidinyl) ester, and butyl... Polymers of diacid and 4-hydroxy-2,2,6,6-tetramethyl-1-ol, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, and poly-{[6-[(1,1,3,3-tetramethylbutyl)-imino]-1,3,5-triazine-2,4-diyl][2-(2,2,6,6-tetramethylpiperidinyl)-amino]-hexylene-[4-(2,2,6,6-tetramethylpiperidinyl)-imino]}; for example, it can be BASF's commercially available Tinuvin 123, Tinuvin 152, Tinuvin 622, Tinuvin 765, Tinuvin 770 or Chimassorb 944, or ADK's commercially available LA-81, LA-87, LA-63P or LA-82.

[0052] In a specific embodiment, the phenolic antioxidant is selected from 2,6-di-tert-butyl-4-methylphenol, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate methylene ester), 2,4-di-tert-butyl-6-methylphenol, 1,6-hexanediol-bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, iso... Tris(3,5-di-tert-butyl-4-hydroxybenzyl) cyanurate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, pentaerythritol tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 3,9-bis(2-(3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy)-1,1-dimethylethyl-2,4,8,10 -Tetraoxane (5.5)undecane, triethylene glycol 4-bis(3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate, 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenol acrylate, 2-(1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl)-4,6-di-tert-pentylphenyl acrylate, 2,4-di-tert-butylphenol, 2,4-di-tert-pentylphenol and 2,6-di-tert-butyl-p-cresol; for example, it may be one or more of Irganox 1010, Irganox 1076, Irganox 1135, Irganox 245, Irganox 3114, Irganox 1098, Irganox 1135, Tinuvin 234 or Tinuvin 326 commercially available from BASF.

[0053] In a preferred embodiment, the melting point of the phosphorus-based antioxidant is <150°C; preferably, the phosphorus-based antioxidant is selected from dioctadecyl pentaerythritol diphosphite, triphenyl phosphate, dibutyl phosphate, tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triethyl phosphate, dioctyl phosphate, diisopropyl phosphate, diphenyl phosphate toluene ester, diphenyl phosphate mono-o-biphenyl ester, tri(butoxyethyl) phosphate, 1,1,3-tris(2-methyl-4-di(tetrazyl)phosphite-5-tert-butylphenyl)butane, distearate pentaerythritol diphosphite Phosphate esters, pentaerythritol diphosphite (2,4-di-tert-butylphenyl), pentaerythritol diphosphite (2,6-di-tert-butylphenyl), tri(diethylphenyl) phosphite, tri(diisopropylphenyl) phosphite, tri(di-n-butylphenyl) phosphite, tri(2,6-di-tert-butylphenyl) phosphite, tri(2,4-di-tert-butylphenyl) phosphite, and triphenyl phosphite; for example, it can be commercially available PEP-8T or PEP-36 from ADK, antioxidant 168 from BASF, or TPP from Hengqiao Industry.

[0054] In this invention, there are no special requirements for the curing accelerator; any commonly used accelerator in the art is acceptable. In a preferred embodiment, the curing accelerator is selected from one or more of amine accelerators, phenolic accelerators, imidazole accelerators, boron trifluoride complexes, organometallic salts, and phosphine accelerators. More preferably, the curing accelerator is an imidazole accelerator and / or a phosphine accelerator.

[0055] In a specific embodiment, the curing accelerator is selected from 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-3,5-dihydroxymethylimidazole, tetraphenylborate, tetrabutylammonium bromide, hexadecyltrimethylammonium bromide, triphenylphosphine, tri(tolyl)phosphine, tetraphenylphosphine bromide, tetraphenylphosphine tetraphenylborate, 2,4,6-triaminomethylphenol, tin octoate, and 1,8-diaza-bicyclo(5.4.0) It can be one or more of the following: undecene-7, triethylenediamine, tri-2,4,6-dimethylaminocresol, and dimethyl butylphosphine phosphate salt; for example, it can be U-CAT-5003 or EH-PX-4MP commercially available from Hengqiao Industry, TPP-K or TPP-MK commercially available from Beixing Chemical Industry, or U-CAT-SA506, U-CAT-SA102, or U-CAT-18X commercially available from San-Apro.

[0056] In this invention, the release agent is a natural wax and / or a synthetic wax. There are no special requirements for the natural wax and the synthetic wax; any commonly used wax in the art is acceptable.

[0057] In a preferred embodiment, the release agent is selected from one or more of stearic acid, hydroxystearic acid, magnesium stearate, calcium stearate, lignite acid and its metal salts, polyethylene wax, palm wax, docosanoic acid, butyl stearate and polyoxyethylene wax; more preferably, the release agent is selected from one or more of stearic acid, polyethylene wax and hydroxystearic acid.

[0058] In this invention, there are no special requirements for the tackifier; any commonly used tackifier in the art is acceptable. In a preferred embodiment, the tackifier is selected from one or more of 4,4'-dithiodimorpholine, bis-(γ-triethoxysilylpropyl)tetrasulfide, bis-[3-(triethoxysilyl)propyl]-disulfide, 3-mercaptopropyltrimethoxysilane, methacryloyloxypropylmethyldimethoxysilane, and 3-[(2,3)-epoxypropoxy]propylmethyldimethoxysilane. More preferably, the tackifier is selected from one or more of bis-[3-(triethoxysilyl)propyl]-disulfide, 3-mercaptopropyltrimethoxysilane, and methacryloyloxypropylmethyldimethoxysilane.

[0059] A second aspect of the present invention provides a flexible epoxy molding compound prepared by the above method.

[0060] The flexible epoxy molding compound prepared by the above method has both low curing shrinkage and low internal stress.

[0061] A third aspect of the present invention provides the application of the above-mentioned flexible epoxy molding compound in electronic component packaging materials.

[0062] The aforementioned flexible epoxy molding compound is used in electronic component packaging materials. After curing, the epoxy molding compound has high light transmittance, temperature and humidity resistance, and high and low temperature impact resistance.

[0063] A fourth aspect of the present invention provides a method for preparing a flexible epoxy molding compound, the method comprising: injection molding the above-mentioned flexible epoxy molding compound in a mold, and then curing it.

[0064] In a preferred embodiment, the injection molding conditions include: a temperature of 120-185°C, a time of 100-300 seconds, and a pressure of <20 MPa.

[0065] In a preferred embodiment, the curing conditions include a temperature of 140-180°C and a time of 2-8 hours.

[0066] The flexible epoxy molding compound prepared by the above method has a light transmittance of over 90%, a warpage of less than 0.1 mm, a tensile strength of over 80 MPa, and an elongation at break of over 10%.

[0067] The following examples further illustrate the flexible epoxy molding compound, its preparation method, and its application according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0068] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are conventional methods in the art. Unless otherwise specified, the experimental materials used in the examples and comparative examples are commercially available; specifically, the raw materials used in the examples and comparative examples listed in Tables 1 and 2 below are as follows: triglycidyl isocyanate (TEPIC-S: manufactured by Nissan Chemical Industries, Ltd., epoxy equivalent 100, softening point 90°C); bisphenol A type epoxy resin (NPES-901: manufactured by Nan-A Resin, epoxy equivalent 450, softening point 70°C); and hexahydrophthalic anhydride curing agent (RIKACID). HH: RIKEN (molecular weight 154.16); chain extenders polyethylene glycol 300, polyethylene glycol 400, polyethylene glycol 2000 and polyethylene glycol 4000 are all commercially available from Aladdin; release agent stearic acid is a commercially available product from Aladdin; antioxidant triphenyl phosphite is a commercially available product from Aladdin; curing accelerator tetraphenylphosphine bromide (UCAT5003: commercially available from Hengqiao Industry); tackifier methacryloxypropylmethyldimethoxysilane (KBM502: manufactured by Shin-Etsu Chemical).

[0069] Example 1

[0070] Preparation of flexible epoxy molding compound S1:

[0071] (1) The chain extender polydiol (polyethylene glycol 2000) and the acid anhydride curing agent (hexahydrophthalic anhydride RIKACID HH) were reacted at 80℃ at a constant temperature of 300r / min for 30min to obtain polydiol anhydride prepolymer.

[0072] (2) Polydiol anhydride prepolymer, triglycidyl isocyanate (TEPIC-S), bisphenol A epoxy resin (NPES-901), antioxidant (triphenyl phosphite), curing accelerator (tetraphenylphosphine bromide UCAT5003), mold release agent (stearic acid), and tackifier (methacryloyloxypropylmethyldimethoxysilane KBM502) were mixed and stirred at 300 r / min for 30 min at 80℃ to obtain flexible epoxy molding compound S1. The raw materials and their amounts are shown in Table 1. The weight ratio of triglycidyl isocyanate to bisphenol A epoxy resin is 1:1.25; the equivalent ratio of the anhydride curing agent to the epoxy group of the epoxy compound is 0.89:1; the chain extender... The molar ratio of the chain extender polydiol to the anhydride curing agent is 0.044:1; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the antioxidant is 100:4; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the curing accelerator is 100:0.5; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the release agent is 100:3; and the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the tackifier is 100:0.3.

[0073] Example 2

[0074] Preparation of flexible epoxy molding compound S2:

[0075] (1) The chain extender polydiol (polyethylene glycol 2000) and the acid anhydride curing agent (hexahydrophthalic anhydride RIKACID HH) were reacted at 80℃ at a constant temperature of 300r / min for 30min to obtain polydiol anhydride prepolymer.

[0076] (2) Polydiol anhydride prepolymer, triglycidyl isocyanate (TEPIC-S), bisphenol A epoxy resin (NPES-901), antioxidant (triphenyl phosphite), curing accelerator (tetraphenylphosphine bromide UCAT5003), mold release agent (stearic acid), and tackifier (methacryloyloxypropylmethyldimethoxysilane KBM502) were mixed and stirred at 300 r / min for 30 min at 80℃ to obtain flexible epoxy molding compound S2. The raw materials and their amounts are shown in Table 1. The weight ratio of triglycidyl isocyanate to bisphenol A epoxy resin is 1:1.25; the equivalent ratio of the anhydride curing agent to the epoxy group of the epoxy compound is 0.89:1; the chain extender... The molar ratio of the chain extender polydiol to the anhydride curing agent is 0.066:1; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the antioxidant is 100:4; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the curing accelerator is 100:0.5; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the release agent is 100:3; and the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the tackifier is 100:0.3.

[0077] Example 3

[0078] Preparation of flexible epoxy molding compound S3:

[0079] (1) The chain extender polydiol (polypropylene glycol 400) and the acid anhydride curing agent (hexahydrophthalic anhydride RIKACID HH) were reacted at 80℃ with a constant temperature of 300r / min for 30min to obtain polydiol anhydride prepolymer.

[0080] (2) Polydiol anhydride prepolymer, triglycidyl isocyanate (TEPIC-S), bisphenol A epoxy resin (NPES-901), antioxidant (triphenyl phosphite), curing accelerator (tetraphenylphosphine bromide UCAT5003), mold release agent (stearic acid), and tackifier (methacryloyloxypropylmethyldimethoxysilane KBM502) were mixed and stirred at 300 r / min for 30 min at 80℃ to obtain flexible epoxy molding compound S3. The raw materials and their amounts are shown in Table 1. The weight ratio of triglycidyl isocyanate to bisphenol A epoxy resin is 1:1.25; the equivalent ratio of the anhydride curing agent to the epoxy group of the epoxy compound is 0.89:1; the chain extender... The molar ratio of the chain extender polydiol to the anhydride curing agent is 0.22:1; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the antioxidant is 100:4; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the curing accelerator is 100:0.5; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the release agent is 100:3; and the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the tackifier is 100:0.3.

[0081] Example 4

[0082] Preparation of flexible epoxy molding compound S4:

[0083] (1) The chain extender polydiol (polypropylene glycol 400) and the acid anhydride curing agent (hexahydrophthalic anhydride RIKACID HH) were reacted at 80℃ with a constant temperature of 300r / min for 30min to obtain polydiol anhydride prepolymer.

[0084] (2) Polydiol anhydride prepolymer, triglycidyl isocyanate (TEPIC-S), bisphenol A epoxy resin (NPES-901), antioxidant (triphenyl phosphite), curing accelerator (tetraphenylphosphine bromide UCAT5003), mold release agent (stearic acid), and tackifier (methacryloyloxypropylmethyldimethoxysilane KBM502) were mixed and stirred at 300 r / min for 30 min at 80℃ to obtain flexible epoxy molding compound S4. The raw materials and their amounts are shown in Table 1. The weight ratio of triglycidyl isocyanate to bisphenol A epoxy resin is 1:1.25; the equivalent ratio of the anhydride curing agent to the epoxy groups of the epoxy compound is 0.89:1; the chain extender... The molar ratio of the chain extender polydiol to the anhydride curing agent is 0.33:1; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the antioxidant is 100:4; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the curing accelerator is 100:0.5; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the release agent is 100:3; and the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the tackifier is 100:0.3.

[0085] Example 5

[0086] Preparation of flexible epoxy molding compound S5:

[0087] (1) The chain extender polydiol (polyethylene glycol 2000 and polypropylene glycol 400 in a weight ratio of 1:1) and the acid anhydride curing agent (hexahydrophthalic anhydride RIKACID HH) were reacted at 80℃ at a constant temperature of 300r / min for 30min to obtain polydiol anhydride prepolymer.

[0088] (2) Polydiol anhydride prepolymer, triglycidyl isocyanate (TEPIC-S), bisphenol A epoxy resin (NPES-901), antioxidant (triphenyl phosphite), curing accelerator (tetraphenylphosphine bromide UCAT5003), mold release agent (stearic acid), and tackifier (methacryloyloxypropylmethyldimethoxysilane KBM502) were mixed and stirred at 300 r / min for 30 min at 80℃ to obtain flexible epoxy molding compound S5. The raw materials and their amounts are shown in Table 1. The weight ratio of triglycidyl isocyanate to bisphenol A epoxy resin is 1:1.25; the equivalent ratio of the anhydride curing agent to the epoxy group of the epoxy compound is 0.89:1; the chain extender... The molar ratio of the chain extender polydiol to the anhydride curing agent is 0.198:1; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the antioxidant is 100:4; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the curing accelerator is 100:0.5; the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the release agent is 100:3; and the weight ratio of the total weight of the chain extender polydiol, anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the tackifier is 100:0.3.

[0089] Example 6

[0090] The implementation was carried out in accordance with Example 1, except that no release agent was added in step (2).

[0091] Example 7

[0092] The implementation was carried out in accordance with Example 1, except that no thickener was added in step (2).

[0093] Example 8

[0094] The implementation was carried out in accordance with Example 1, except that the weight ratio of the triglycidyl isocyanurate to the bisphenol A type epoxy resin was 1:0.1; and the equivalent ratio of the acid anhydride curing agent to the epoxy groups of the epoxy compound was 0.7:1.

[0095] Example 9

[0096] The implementation was carried out in accordance with Example 1, except that the weight ratio of the triglycidyl isocyanurate to the bisphenol A type epoxy resin was 1:1.5; and the equivalent ratio of the acid anhydride curing agent to the epoxy groups of the epoxy compound was 1.2:1.

[0097] Comparative Example 1

[0098] The implementation was carried out in accordance with Example 1, except that the chain extender polydiol was polyethylene glycol 300.

[0099] Comparative Example 2

[0100] The implementation was carried out in accordance with Example 1, except that the chain extender polydiol was polypropylene glycol 4000.

[0101] Comparative Example 3

[0102] The implementation was carried out in accordance with Example 1, except that the molar ratio of the chain extender polydiol to the anhydride curing agent was 0.022:1.

[0103] Comparative Example 4

[0104] The implementation was carried out in accordance with Example 3, except that the molar ratio of the chain extender polydiol to the anhydride curing agent was 0.55:1.

[0105] Comparative Example 5

[0106] The implementation was carried out in accordance with Example 1, except that the chain extender polyethylene glycol 2000 was not added.

[0107] Comparative Example 6

[0108] The implementation was carried out in accordance with Example 1, except that the weight ratio of the triglycidyl isocyanurate to the bisphenol A epoxy resin was 1:2.

[0109] Comparative Example 7

[0110] The implementation was carried out in accordance with Example 1, except that the equivalent ratio of the anhydride curing agent to the epoxy group of the epoxy compound was 0.6:1.

[0111] Test case

[0112] The properties of the flexible epoxy molding compounds prepared in the above embodiments and comparative examples after curing were tested. The test indicators included coefficient of linear expansion, light transmittance, aging resistance, moisture resistance, shrinkage, warpage, tensile strength, and elongation at break. The test methods for each property are as follows:

[0113] (1) Coefficient of linear expansion (α1): The flexible epoxy molding compounds prepared in the examples and comparative examples were injected into a special mold using a molding press under the process conditions of mold temperature of 175℃ and molding time of 110s, so that they were cured into cylindrical hard blocks with a diameter of 3mm and a height of 5mm. After the obtained cylindrical hard blocks were cured in an oven at 150℃ for 2h, the coefficient of linear expansion α1 and the glass transition temperature Tg were tested under nitrogen conditions at 35℃-250℃ and a heating rate of 10℃ / min. The smaller the coefficient of linear expansion α1, the smaller the shrinkage stress of the cured product. The test results are shown in Table 1.

[0114] (2) Transmittance: The flexible epoxy molding compounds prepared in the examples and comparative examples were injected into a special mold using a molding machine under the process conditions of mold temperature of 175°C and molding time of 110s, and then cured into a 1mm thick sheet. After the obtained sheet was cured in an oven at 150°C for 2 hours, the transmittance at a wavelength of 420nm was tested using a Shimadzu UV2600 spectrophotometer. The higher the transmittance value, the higher the transmittance. The test results are shown in Table 1.

[0115] (3) Aging resistance: The thin film used for the above transmittance test was subjected to three reflow soldering tests. Each test was conducted at four temperatures: 220℃, 205℃, 200℃ and 295℃, with each test lasting about 10 minutes. After three reflow soldering tests, the transmittance at a wavelength of 420nm was tested using a Shimadzu UV2600 spectrophotometer. The higher the transmittance, the better the temperature resistance of the material. The test results are shown in Table 1.

[0116] (4) Moisture resistance: The flexible epoxy molding compound prepared in the examples and comparative examples was used to encapsulate 20 LED beads respectively. The 20 encapsulated LED beads (encapsulated by Dongguan Dezhen Light Source) were subjected to an 85℃ 85%RH storage test. After continuous storage with a constant current of 10mA forward power for 336 hours, the dead LED status was tested by using a constant current power supply. The LED beads that could be lit normally were rated as ○, and the LED beads that could not be lit were rated as ╳. The fact that the LED beads could be lit indicates that the moisture resistance is good. The fact that the LED beads could not be lit indicates that the moisture penetration caused the chip or gold wire corrosion, resulting in the failure of the lamp. The test results are shown in Table 1.

[0117] (5) Shrinkage: The flexible epoxy molding compound prepared in the examples and comparative examples was used to encapsulate 40 LED beads respectively. The encapsulated 40 LED beads (encapsulated by Dongguan Dezhen Light Source) were subjected to 2000 cycles of thermal shock testing using a thermal shock tester. One cycle consisted of a 15-minute exposure at -45°C and a 15-minute exposure at 125°C. The number of cracks was observed using a digital microscope, and a constant current power supply was used to detect whether any LEDs were dead. No dead LEDs or cracks were rated as ○, and everything else was rated as ╳. Dead LEDs indicate that the LEDs are broken and not lit. The test results are shown in Table 1.

[0118] (6) Warpage: The flexible epoxy molding compound prepared in the examples and comparative examples was placed on a copper sheet and cured for 10 minutes at a mold temperature of 175°C to form a solid shape. After curing at 100°C for 2 hours, the warpage was measured using a warpage tester. Warpage deformation is one of the important indicators for evaluating product quality. It is used to describe the degree of curvature of a plane in space. Numerically, it is defined as the distance between the two points that are farthest apart in the height direction of the warped plane. The closer the value is to 0, the smaller the shrinkage and the smaller the stress. The test results are shown in Table 1.

[0119] (7) Tensile strength and elongation at break: Tensile strength and elongation at break were measured by preparing type 1 specimens according to the national standard GB / T 528-2009. The test results are shown in Table 1.

[0120] Table 1

[0121]

[0122] As can be seen from the results in Table 1, the flexible epoxy molding compound prepared by the method described in this invention has good linear expansion coefficient α1, light transmittance, aging resistance, moisture resistance, shrinkage, warpage, tensile strength, and elongation at break after curing. When used as a packaging material for electronic components, it has a higher bonding force with the substrate surface and is not easy to crack or peel off. At the same time, it has higher light transmittance, aging resistance, and flexibility, while the low water absorption rate can effectively ensure the airtightness of electronic components, making it a promising application in the field of electronic component packaging.

[0123] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method of making a flexible epoxy molding compound, characterized by, The method includes: (1) The chain extender polydiol and the acid anhydride curing agent are reacted to obtain polydiol acid anhydride prepolymer; (2) Mix the polydiol anhydride prepolymer, epoxy, antioxidant, curing accelerator, optional release agent and optional tackifier; The epoxy compound is triglycidyl isocyanurate and bisphenol A type epoxy resin, wherein the weight ratio of triglycidyl isocyanurate to bisphenol A type epoxy resin is 1:0.1-1.

5. The equivalent ratio of the anhydride curing agent to the epoxy group of the epoxy compound is 0.7-1.2:1; The molar ratio of the chain extender polydiol to the anhydride curing agent is 0.04-0.5:1; The chain extender, polydiol, has a molecular weight of 400-2000.

2. The method of claim 1, wherein, In step (1), the reaction conditions include: a temperature of 20-90℃ and a time of 10-30 min.

3. The method according to claim 1 or 2, characterized in that, In step (2), the mixing conditions include: a temperature of 20-100℃ and a time of 10-30 min.

4. The method of claim 3, wherein, The total weight ratio of the chain extender (polydiol), acid anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the antioxidant is 100:2-6; and / or The total weight ratio of the chain extender (polydiol), acid anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the curing accelerator is 100:0.1-0.8; and / or The total weight ratio of the chain extender (polydiol), acid anhydride curing agent, triglycidyl isocyanate, and bisphenol A epoxy resin to the weight of the release agent is 100:0-5; and / or The total weight ratio of the chain extender polydiol, acid anhydride curing agent, triglycidyl isocyanate and bisphenol A epoxy resin to the weight of the tackifier is 100:0-2.

5. The method according to claim 1 or 4, characterized in that, The bisphenol A type epoxy resin has an epoxy equivalent of 90-1000 g / eq; and / or The molecular weight of the anhydride curing agent is 100-500.

6. The method according to claim 5, characterized in that, The oxidant is selected from one or more of amine-based antioxidants, phosphorus-based antioxidants, and phenolic antioxidants; and / or The curing accelerator is selected from one or more of amine accelerators, phenolic accelerators, imidazole accelerators, boron trifluoride complexes, organometallic salts, and phosphine accelerators.

7. The method according to claim 1 or 6, characterized in that, The release agent is a natural wax and / or a synthetic wax; and / or The tackifier is selected from one or more of 4,4'-dithiodimorpholine, bis-(γ-triethoxysilylpropyl)tetrasulfide, bis-[3-(triethoxysilyl)propyl]-disulfide, 3-mercaptopropyltrimethoxysilane, methacryloyloxypropylmethyldimethoxysilane, and 3-[(2,3)-epoxypropoxy]propylmethyldimethoxysilane.

8. A flexible epoxy molding compound prepared by the method according to any one of claims 1-7.

9. The application of the flexible epoxy molding compound according to claim 8 in electronic component packaging materials.

10. A method for preparing flexible epoxy molding compound, characterized in that, The method includes: injection molding the flexible epoxy molding compound of claim 8 into a mold, and then curing it; Preferably, the injection molding conditions include: a temperature of 120-185℃, a time of 100-300s, and a pressure of <20MPa; and / or The curing conditions include a temperature of 140-180℃ and a time of 2-8 hours.

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