Epoxy resin composition and application thereof

Abstract

The invention provides an epoxy resin composition and application thereof, and the epoxy resin composition comprises the following components in parts by weight: 100 parts of epoxy resin, 30-200 parts of a curing agent, 30-100 parts of a flexibilizer, 1-100 parts of a filler and 5-60 parts of a styrene-maleic anhydride copolymer and / or a derivative thereof, the toughening agent at least comprises acrylate rubber. According to the epoxy resin composition, an adhesive film containing the epoxy resin composition is good in normal-temperature storage stability and high-temperature reactivity and can react quickly; the damping loss factor of the adhesive film in the range of 0-100 DEG C is low, the stability of the damping loss factor is good, the elastic modulus is high, and meanwhile, the adhesive film also has high toughness and bonding strength.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesive films, and specifically relates to an epoxy resin composition and application thereof. Background Art

[0002] Pure adhesive film for flexible printed circuits (FPC) is mainly used for bonding between PI reinforcement boards, FR4 reinforcement boards, steel reinforcement boards, and multilayer boards, as well as bonding between FPC and other electronic components or parts. In recent years, the electronics industry has developed rapidly, the use of FPC boards has increased significantly, and the scope of application has been greatly broadened. As a result, the use of pure adhesive film for FPC has also increased rapidly. As electronic products develop in a lighter, thinner, and more sophisticated direction, and tend to be used in some harsh or extreme environments, higher requirements are placed on the performance of pure adhesive film for FPC.

[0003] Commonly used pure adhesive films for FPC include epoxy system pure adhesive films. However, epoxy system adhesive films have poor heat resistance and short storage life. After being placed for a long time and then pressed together, they are prone to abnormal appearance of "orange peel texture", causing scrapping and affecting customer experience. Therefore, epoxy system pure adhesive films usually require end-carboxyl nitrile rubber for toughening, thereby effectively improving peel strength and heat resistance. However, due to the addition of nitrile rubber, epoxy resin will slowly pre-cure at room temperature without adding curing agent and accelerator, which seriously affects the storage life of epoxy pure adhesive film, greatly reducing the fluidity and adhesion of the pure adhesive film, resulting in the easy generation of orange peel texture during pressing.

[0004] In addition, with the introduction of new electronic products or new functions and structures of electronic products, new requirements are put forward for the performance of pure adhesive films for FPC. For example, pure adhesive films used in pressure sensors to bond FPC and other components require that the pure adhesive films have a high elastic modulus and a low and stable damping loss factor within a certain temperature range after curing in order to ensure the life and sensitivity of the sensor. However, nitrile rubber is a toughening material. If the amount is too small, the toughness and bonding strength of the pure adhesive film will be insufficient. If the amount is too large, the elastic modulus of the pure adhesive film will be too low within a certain temperature range after curing, or the damping loss factor will be too large, resulting in poor stability.

[0005] Therefore, it is an urgent problem to be solved in this field to develop an epoxy resin material that can improve the elastic modulus and damping loss factor stability of the film and reduce the damping loss factor, while ensuring that the film has high toughness and peel strength, as well as good room temperature storage stability and high temperature rapid reactivity. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention aims to provide an epoxy resin composition and its application. The film comprising the epoxy resin composition has a low damping loss factor, good stability of the damping loss factor, and a high elastic modulus; at the same time, the film has good room temperature storage stability and high temperature fast reactivity as well as high toughness and bonding strength.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides an epoxy resin composition, which comprises, by weight, 100 parts of epoxy resin, 30 to 200 parts of curing agent, 30 to 100 parts of toughening agent, 1 to 100 parts of filler and 5 to 60 parts of styrene-maleic anhydride copolymer and / or its derivatives; the toughening agent comprises at least acrylate rubber.

[0009] In the present invention, a specific content of styrene-maleic anhydride copolymer and / or its derivatives are added to be compounded with other components, and the toughening agent at least includes acrylic rubber. On the premise of ensuring that the film has excellent toughness and peel strength, the damping loss factor of the film in the range of 0 to 100° C. is greatly reduced and the stability of the damping loss factor is improved. At the same time, the film also has a higher elastic modulus, excellent storage stability at room temperature and high-temperature rapid responsiveness.

[0010] In the present invention, 30 to 200 parts of curing agent can be, for example, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, 150 parts, 160 parts, 170 parts, 180 parts, 190 parts, 200 parts, etc.; more preferably, 50 to 150 parts.

[0011] In the present invention, 30 to 100 parts of the toughening agent may be, for example, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, etc.; more preferably, 50 to 80 parts.

[0012] In the present invention, 1 to 100 parts of filler can be, for example, 1 part, 5 parts, 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, etc.; more preferably, it is 2 to 30 parts.

[0013] In the present invention, 5 to 60 parts of styrene-maleic anhydride copolymer and / or its derivatives can be, for example, 5 parts, 6 parts, 8 parts, 9 parts, 10 parts, 12 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, etc.; more preferably, 10 to 40 parts.

[0014] Preferably, in the styrene-maleic anhydride copolymer and / or its derivatives, the mass ratio of the styrene structural unit to the maleic anhydride structural unit is (1-8):1, wherein the specific values ​​in (1-8) can be, for example, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, 5.8, 6, 6.2, 6.4, 6.6, 6.8, 7, 7.2, 7.4, 7.6, 7.8, 8, etc.; more preferably (3-8):1.

[0015] In the present invention, if the content of styrene structural units in the styrene-maleic anhydride copolymer and / or its derivatives is too high, the toughness and bonding strength of the adhesive film will be reduced to a certain extent.

[0016] Preferably, the styrene-maleic anhydride copolymer derivative includes at least one of esterified styrene-maleic anhydride copolymer, amidated styrene-maleic anhydride copolymer and amidated styrene-maleic anhydride copolymer.

[0017] In the present invention, the styrene-maleic anhydride copolymer and / or its derivatives can be selected from, for example, the commercially available SMA EF series of Cray Valley Company.

[0018] Preferably, the toughening agent further includes at least one of phenoxy resin, polyvinyl alcohol, polyvinyl acetal resin, nitrile rubber, core-shell rubber, SEBS rubber or other thermoplastic elastomers.

[0019] In the present invention, the nitrile rubber is preferably a rubber with a weight average molecular weight of 20 to 50 W, illustratively selected from XER32 of JSR Corporation of Japan and 1072CG of Nandi Corporation of Taiwan, China. The phenoxy resin is preferably a phenoxy resin with a weight average molecular weight of 30,000 to 70,000.

[0020] Preferably, the toughening agent includes at least one of acrylate rubber, phenoxy resin or nitrile rubber; and at least includes acrylate rubber.

[0021] Preferably, the weight average molecular weight of the acrylic rubber is 200,000 to 1,000,000, for example, 200,000, 300,000, 400,000, 500,000, 600,000, 700,000, 800,000, 900,000, 1,000,000, etc.

[0022] Exemplarily, the acrylic rubber can be selected from Japan's Nagase Chemical SG-70L, SG-708-6, SG-P3TEA, SG-P3, SG-80H, WS-023, etc.; more preferably, the acrylic rubber includes acrylic rubber containing epoxy groups, such as SG-P3, SG-80H, etc.

[0023] Preferably, the curing agent includes a first component, or the curing agent includes a first component and a second component.

[0024] The first component includes at least one of amine compounds, imidazole compounds, amide compounds, anhydride compounds, phenolic compounds, benzoxazine compounds, active ester compounds, and thermally initiated cationic curing agents; the second component includes phenolic resin.

[0025] In the present invention, the bonding strength of the adhesive film can be significantly improved by adding the second component.

[0026] Preferably, the first component includes at least one latent curing agent.

[0027] Preferably, the latent curing agent at least includes a microcapsule-type latent curing agent.

[0028] In the present invention, the latent curing agent also includes a non-microcapsule type latent curing agent, such as an imidazole type non-microcapsule type latent curing agent, which can be exemplarily selected from ADEKA's EH-5011, 5046S, 2110K, etc.

[0029] In the present invention, the heat curing temperature of the microcapsule type latent curing agent is above 90°C. The microcapsule type latent curing agent is divided into imidazole, modified imidazole, amine, and modified amine room temperature fast reaction curing agent according to its curing agent component. The microcapsule type curing agent is a mixture pre-dispersed with liquid epoxy resin, such as HXA3792, HXA3941HP, HXA3921HP, HXA3922, HXA3932HP, HXA3042HP, etc. of Asahi Chemical.

[0030] Preferably, the epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, tetraphenylethane epoxy resin, triphenylmethane epoxy resin, biphenyl epoxy resin, naphthalene ring epoxy resin, dicyclopentadiene epoxy resin, phosphorus-containing epoxy resin, nitrogen-containing epoxy resin, multifunctional epoxy resin, isocyanate epoxy resin, phenolic epoxy resin, methylphenolic epoxy resin, bisphenol-type phenolic epoxy resin, polyphenylene ether modified epoxy resin, alicyclic epoxy resin, allyl glycidyl epoxy resin, glycidyl amine epoxy resin, glycidyl ester epoxy resin, chelate epoxy resin or dendritic epoxy resin.

[0031] In the present invention, the epoxy resin is preferably a mixture of one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, biphenyl epoxy resin or naphthalene epoxy resin which are solid at room temperature. The prepared adhesive film has better toughness and lower adhesive surface adhesion. The lower adhesive surface adhesion gives the adhesive film better die-cutting performance.

[0032] Preferably, the filler includes at least one of angular silica, spherical silica, fumed silica, alumina, aluminum hydroxide, aluminum nitride, boron nitride, titanium dioxide, strontium titanate, barium titanate, barium sulfate, talc, calcium silicate, calcium carbonate, mica, polytetrafluoroethylene or graphene.

[0033] In the present invention, if the filler is added in too much amount, it will make it difficult to disperse the curing agent, especially the microcapsule type latent curing agent, which is easy to lose its latency; if the filler is added in too little amount, the amount of hot pressing glue overflow during use of the film will increase.

[0034] In the present invention, the filler may be surface treated with a silane coupling agent, and may be directly added or pre-prepared into a filler dispersion or paste and mixed with other components to obtain an epoxy resin composition.

[0035] In the present invention, the filler is preferably angular silica, spherical silica, and fumed silica. Compared with some alkaline fillers such as aluminum hydroxide and magnesium hydroxide, the obtained adhesive film has higher high-temperature rapid reactivity. More preferably, the angular silica and spherical silica are surface-treated fillers, and the surface treatment agent used can be a silane coupling agent, and the silane coupling agent is preferably a silane coupling agent containing an epoxy group. After the silica filler is treated with an epoxy group silane coupling agent, the obtained adhesive film has better bonding properties, especially still has higher bonding properties after wet heat aging.

[0036] In the present invention, the filler includes at least 1 to 10 parts of fumed silica, for example, 1 part, 2 parts, 4 parts, 6 parts, 8 parts, 10 parts, etc.

[0037] In the present invention, illustratively, the angular silica can be selected from Jinyi's L series, the spherical silica can be selected from Jinyi's Q series, and the fumed silica can be selected from Evonik's AEROSIL R series.

[0038] In the present invention, the epoxy resin composition may further include other modifiers such as flame retardants, tackifying resins, matting powder, etc. according to actual needs.

[0039] It should be noted that the contents of each component in the present invention, that is, the "parts" mentioned, all refer to parts by solid weight.

[0040] In the present invention, the preparation method of the epoxy resin composition comprises: mixing the components uniformly.

[0041] In a second aspect, the present invention provides an adhesive film, comprising a release film and an epoxy resin adhesive layer disposed on one surface of the release film; the epoxy resin adhesive layer comprises the epoxy resin composition described in the first aspect.

[0042] In the present invention, the thickness of the adhesive film can be determined according to actual needs, for example, it can be 5 to 20 um.

[0043] In a third aspect, the present invention provides a method for preparing the adhesive film according to the second aspect, the preparation method comprising:

[0044] The epoxy resin composition is mixed with a solvent to obtain a resin adhesive solution; the resin adhesive solution is coated on one surface of a release film, and dried to obtain the adhesive film.

[0045] Preferably, the solid content of the resin glue is 20-40%.

[0046] Preferably, the drying temperature is 70-90° C. and the drying time is 1-10 min.

[0047] In the present invention, the solvent includes commonly used solvents such as toluene, butanone, acetone, ethyl acetate, propylene glycol methyl ether, etc., preferably one or a mixture of low-polar toluene, ethyl acetate, propylene glycol methyl ether.

[0048] In the present invention, a protective film can be further laminated on the surface of the epoxy adhesive film as required.

[0049] In a fourth aspect, the present invention provides a flexible circuit board, wherein the flexible circuit board comprises the epoxy resin composition described in the first aspect or the adhesive film described in the second aspect.

[0050] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0051] The system refers to an equipment system, a device system or a production device.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The epoxy resin composition provided by the present invention is added with a specific content of styrene-maleic anhydride copolymer and / or its derivatives, and the toughening agent includes at least acrylic rubber. On the premise of ensuring that the film has excellent toughness and peel strength, the damping loss factor of the film in the range of 0 to 100° C. is greatly reduced and the stability of the damping loss factor is improved. At the same time, the film also has a higher elastic modulus, excellent room temperature storage stability and high-temperature rapid responsiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a schematic diagram of the structure of the adhesive film of the present invention;

[0055] Wherein: 1-epoxy resin adhesive layer; 2-release film. DETAILED DESCRIPTION

[0056] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0057] The materials used in all embodiments and comparative examples of the present invention are as follows:

[0058] A1: YD011, bisphenol A epoxy resin, Guodu Chemical;

[0059] A2: YDF-2001, bisphenol F epoxy resin, Guodu Chemical;

[0060] B1: HXA3932, a mixture of curing agent and epoxy resin, Asahi Chemical;

[0061] B2: SH6380, phenolic resin, Shandong Shengquan;

[0062] C1: SG-P3, acrylic rubber, epoxy value 0.21eq / Kg Japan Nagase;

[0063] C2: XER32, nitrile rubber, Japan JSR;

[0064] D1:L55, angular silica, Suzhou Jinyi;

[0065] D2:Q015, spherical silica, Suzhou Jinyi;

[0066] D3: R208, fumed silica, Evonik (Shanghai);

[0067] E1: styrene-maleic anhydride copolymer, EF80, Crayville, styrene and maleic anhydride ratio of 8:1;

[0068] E2: styrene-maleic anhydride copolymer, EF40, Crayville, styrene and maleic anhydride ratio of 4:1.

[0069] Examples 1 to 8, Comparative Examples 1 to 2

[0070] Examples 1 to 8 and Comparative Examples 1 to 2 respectively provide an epoxy resin composition, and the formulas of the epoxy resin compositions are shown in Tables 1 to 2 in terms of solid weight; wherein, “ / ” indicates that the component is not included in the formula.

[0071] Table 1

[0072]

[0073] Table 2

[0074]

[0075] Application Examples

[0076] A film, the structural schematic diagram of the film is as follows Figure 1 As shown, it includes an epoxy resin adhesive layer 1 and a release film 2 arranged in sequence; the epoxy resin adhesive layer includes the epoxy resin compositions provided by Examples 1 to 8 and Comparative Examples 1 to 2 respectively; the preparation method of the adhesive film includes: mixing the epoxy resin composition with toluene to obtain a resin solution with a solid content of 30%; applying the resin adhesive solution to one surface of the release film, using an oven at 80°C / 5min to dry the solvent in the adhesive film, and preparing a pure adhesive film with a thickness of 10-15um.

[0077] Performance Testing

[0078] (1) Adhesion strength: FPC, SUS304 stainless steel plate, and pure adhesive film were cut into 1cm×20cm strips, and the pure adhesive film was laminated between the FPC and the SUS304 stainless steel plate, with the PI surface of the FPC in contact with the epoxy pure adhesive film. After pressing at 180℃ / 30s / 4MPa, they were baked at 120℃ / 1hr to prepare strips. The peel strength between the FPC and the pure adhesive film was then tested, with a peel angle of 90° and a tensile rate of 100mm / min. The peel strength of the pure adhesive film is measured by the peel strength. When the peel strength exceeds 15N / cm, the PI film will be torn.

[0079] (2) Reaction rate of storage at room temperature: The reaction rate of epoxy groups after the film is stored at room temperature for 15 days is compared with the initial state. This is used to evaluate the room temperature storage performance of the epoxy film. The lower the reaction rate of epoxy groups after being stored at room temperature for a period of time, the better the room temperature storage performance of the epoxy film.

[0080] (3) High-temperature rapid reaction rate: After the epoxy film is baked at 180°C / 30s, the reaction rate of the epoxy group after baking is tested compared with that before baking. This is used to evaluate the high-temperature reactivity of the epoxy film. The higher the reaction rate of the epoxy group, the better the high-temperature rapid reactivity of the epoxy film.

[0081] (4) Modulus and damping loss factor: The epoxy films were laminated to a thickness of 30 μm and baked at 180°C / 30s+120°C / 1hr. The modulus of the films at 50°C and the maximum value of the damping loss factor in the range of 0-100°C, as well as the range of the damping loss factor in the range of 0-100°C, were tested using the DMA tensile method (temperature rise 10°C / min, frequency 1 Hz).

[0082] The specific test results are shown in Table 3.

[0083] Table 3

[0084]

[0085] It can be seen from Table 3 that the adhesive film made from the epoxy resin composition provided by the present invention has good storage stability at room temperature, good high-temperature reactivity, and can react quickly; and the adhesive film has a low damping loss factor in the range of 0 to 100°C (≤0.1), good stability of the damping loss factor (0-100°C damping loss factor range ≤0.05), a high elastic modulus (≥1.2 GPa), and at the same time, high toughness and bonding strength.

[0086] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An epoxy resin composition, characterized in that The epoxy resin composition comprises, by weight, 100 parts of epoxy resin, 30 to 200 parts of curing agent, 30 to 100 parts of toughening agent, 1 to 100 parts of filler and 5 to 60 parts of styrene-maleic anhydride copolymer and / or its derivatives; The toughening agent at least includes acrylic rubber.

2. The epoxy resin composition according to claim 1, characterized in that In the styrene-maleic anhydride copolymer and / or its derivatives, the mass ratio of the styrene structural unit to the maleic anhydride structural unit is (1-8):1, more preferably (3-8):

1.

3. The epoxy resin composition according to claim 1 or 2, characterized in that The styrene-maleic anhydride copolymer derivative includes at least one of esterified styrene-maleic anhydride copolymer, amidated styrene-maleic anhydride copolymer and amidated styrene-maleic anhydride copolymer.

4. The epoxy resin composition according to any one of claims 1 to 3, characterized in that The toughening agent also includes at least one of phenoxy resin, polyvinyl alcohol, polyvinyl acetal resin, nitrile rubber, core-shell rubber, SEBS rubber or other thermoplastic elastomers; Preferably, the toughening agent includes at least one of acrylate rubber, phenoxy resin or nitrile rubber; and at least includes acrylate rubber.

5. The epoxy resin composition according to any one of claims 1 to 4, characterized in that The curing agent includes a first component, or the curing agent includes a first component and a second component; The first component includes at least one of an amine compound, an imidazole compound, an amide compound, an acid anhydride compound, a phenolic compound, a benzoxazine compound, an active ester compound, and a heat-initiated cationic curing agent; the second component includes a phenolic resin; Preferably, the first component includes at least one latent curing agent; Preferably, the latent curing agent at least includes a microcapsule-type latent curing agent.

6. The epoxy resin composition according to any one of claims 1 to 5, characterized in that The epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, tetraphenylethane epoxy resin, triphenylmethane epoxy resin, biphenyl epoxy resin, naphthalene epoxy resin, dicyclopentadiene epoxy resin, phosphorus-containing epoxy resin, nitrogen-containing epoxy resin, multifunctional epoxy resin, isocyanate epoxy resin, novolac epoxy resin, methyl novolac epoxy resin, bisphenol-type novolac epoxy resin, polyphenylene ether modified epoxy resin, alicyclic epoxy resin, allyl glycidyl epoxy resin, glycidylamine epoxy resin, glycidyl ester epoxy resin, chelate epoxy resin or dendritic epoxy resin; Preferably, the filler includes at least one of angular silica, spherical silica, fumed silica, alumina, aluminum hydroxide, aluminum nitride, boron nitride, titanium dioxide, strontium titanate, barium titanate, barium sulfate, talc, calcium silicate, calcium carbonate, mica, polytetrafluoroethylene or graphene.

7. A film, characterized in that: The adhesive film comprises a release film and an epoxy resin adhesive layer arranged on one surface of the release film; The epoxy resin adhesive layer comprises the epoxy resin composition according to any one of claims 1 to 6.

8. A method for preparing an adhesive film according to claim 7, characterized in that: The preparation method comprises: The epoxy resin composition is mixed with a solvent to obtain a resin adhesive solution; the resin adhesive solution is coated on one surface of a release film, and dried to obtain the adhesive film.

9. The preparation method according to claim 8, characterized in that: The solid content of the resin glue is 20-40%; Preferably, the drying temperature is 70-90° C. and the drying time is 1-10 min.

10. A flexible circuit board, characterized in that: The flexible circuit board comprises the epoxy resin composition according to any one of claims 1 to 6 or the adhesive film according to claim 7.

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