An epoxy resin composition and use thereof

Abstract

The present application provides an epoxy resin composition and its application, the epoxy resin composition comprises 100 parts of epoxy resin, 30-200 parts of curing agent, 30-100 parts of toughening agent, 1-100 parts of filler and 5-80 parts of polyarylate by weight; the toughening agent at least comprises acrylate rubber. In the present application, the adhesive film comprising the epoxy resin composition has good room temperature storage stability, good high temperature reactivity and can quickly react; and the adhesive film has low damping loss factor, good stability of the damping loss factor, high elastic modulus, high toughness and high bonding strength in the range of 0-100 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of adhesive film technology, specifically relating to an epoxy resin composition and its application. Background Technology

[0002] Pure adhesive film for flexible printed circuit boards (FPCs) is mainly used for bonding PI reinforcing boards, FR4 reinforcing boards, steel sheet reinforcing boards, and multilayer boards, as well as bonding FPCs to other electronic components or parts. In recent years, the electronics industry has developed rapidly, leading to a significant increase in the use of FPC boards and a substantial expansion of their application scope. Consequently, the use of pure adhesive film for FPCs has also increased rapidly. As electronic products move towards thinner, lighter, and more refined designs, and are increasingly used in harsh or extreme environments, higher performance requirements are placed on pure adhesive film for FPCs.

[0003] Epoxy-based pure adhesive films are commonly used in FPC applications. However, epoxy-based films suffer from poor heat resistance and short shelf life. Prolonged storage followed by re-lamination can easily result in an "orange peel" appearance, leading to scrap and negatively impacting customer experience. Therefore, epoxy-based pure adhesive films typically require carboxyl-terminated nitrile butadiene rubber (NBR) for toughening, effectively improving peel strength and heat resistance. However, the addition of NBR causes the epoxy resin to slowly pre-cur at room temperature even without curing agents and accelerators, severely affecting the shelf life of the epoxy pure adhesive film. This significantly reduces the film's flowability and adhesion, making it prone to orange peel texture during lamination.

[0004] Furthermore, with the introduction of new electronic products or their new functions and structures, new requirements have been placed on the performance of pure adhesive films used in FPCs. For example, pure adhesive films used in pressure sensors to bond FPCs and other components require high elastic modulus and low and stable damping loss factor within a certain temperature range after curing, in order to ensure the sensor's lifespan and sensitivity. However, nitrile rubber is a toughening material; too little nitrile rubber will result in insufficient toughness and bonding strength of the pure adhesive film, while too much nitrile rubber will result in excessively low elastic modulus or excessively high damping loss factor within a certain temperature range after curing, leading to poor stability.

[0005] Therefore, developing an epoxy resin material that can improve the stability of the elastic modulus and damping loss factor of the adhesive film, reduce the damping loss factor, and at the same time ensure that the adhesive film has high toughness and peel strength, as well as good room temperature storage stability and high temperature rapid reactivity is an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an epoxy resin composition and its applications. The epoxy resin composition comprises a film with a low damping loss factor, good stability of the damping loss factor, and a high elastic modulus; simultaneously, the film exhibits good room temperature storage stability, high-temperature rapid reaction, and high toughness and adhesive strength.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an epoxy resin composition comprising, by weight, 100 parts epoxy resin, 30 to 200 parts curing agent, 30 to 100 parts toughening agent, 1 to 100 parts filler and 5 to 80 parts polyarylate; wherein the toughening agent comprises at least acrylate rubber.

[0009] In this invention, the toughening agent includes at least acrylate rubber and a specific amount of rigid polyarylate is added and compounded with other components. While ensuring that the film has excellent toughness and peel strength, it significantly reduces the damping loss factor of the film in the range of 0 to 100°C and improves the stability of the damping loss factor. At the same time, it also makes the film have a high elastic modulus, excellent room temperature storage stability and high temperature rapid reactivity.

[0010] In this 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 this invention, 30 to 100 parts of toughening agent can be, for example, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, etc.; more preferably, 50 to 80 parts.

[0012] In this 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, 2 to 30 parts.

[0013] In this invention, 5 to 80 parts of polyarylate 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, 65 parts, 70 parts, 75 parts, 80 parts, etc.; more preferably, 10 to 50 parts.

[0014] Preferably, the polyarylate has the structure shown in Formula I.

[0015]

[0016] In Formula I, R is selected from at least one of straight-chain or branched alkyl groups with ≥1 carbon atom, oxygen atom, or sulfoxide group; X may be the same or different, and each is independently selected from at least one of H, halogen, substituted or unsubstituted straight-chain or branched alkyl groups with ≥1 carbon atom.

[0017] In this invention, the straight-chain or branched alkyl group with ≥1 carbon atom can be, for example, a straight-chain or branched alkyl group with 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms; exemplary, including but not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, n-hexyl, etc.; the halogen includes F, Cl, Br, and I.

[0018] Preferably, the number average molecular weight of the polyarylate is 3,000 to 50,000, for example, it can be 3,000, 3,500, 4,000, 4,500, 5,000, 6,000, 7,000, 8,000, 9,000, 10,000, 12,000, 14,000, 16,000, 18,000, 20,000, 22,000, 24,000, 26,000, 28,000, 30,000, 32,000, 34,000, 36,000, 38,000, 40,000, 42,000, 44,000, 46,000, 48,000, 50,000, etc.; preferably, it is 10,000 to 35,000.

[0019] Preferably, the glass transition temperature of the polyarylate is 100–300°C, for example, it can be 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C, 300°C, etc.; more preferably, it is 200–300°C.

[0020] In this invention, the polyarylate can be selected from commercially available products such as UNIFINER's V-575, W-575, U-100, M-2000H, M-2040H, and M-2040, and DIC's HPC-800.

[0021] 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.

[0022] In this invention, the nitrile rubber is preferably a rubber with a weight-average molecular weight of 20 to 50 W, and exemplaryly selected from XER32 of JSR Corporation of Japan and 1072CG of Nanti Corporation of Taiwan. The phenoxy resin is preferably a phenoxy resin with a weight-average molecular weight of 30,000 to 70,000.

[0023] Preferably, the toughening agent includes at least one of acrylate rubber, phenoxy resin, or nitrile rubber; and at least includes acrylate rubber.

[0024] Preferably, the weight-average molecular weight of the acrylate rubber is 200,000 to 1,000,000, for example, it can be 200,000, 300,000, 400,000, 500,000, 600,000, 700,000, 800,000, 900,000, 1,000,000, etc.

[0025] For example, the acrylate rubber may be selected from Nagase Chemical SG-70L, SG-708-6, SG-P3TEA, SG-P3, SG-80H, WS-023, etc.; more preferably, the acrylate rubber includes acrylate rubber containing epoxy groups, such as SG-P3, SG-80H, etc.

[0026] Preferably, the curing agent comprises a first component, or the curing agent comprises a first component and a second component.

[0027] The first component includes at least one of amine compounds, imidazole compounds, amide compounds, acid anhydride compounds, phenolic compounds, benzoxazine compounds, active ester compounds, and thermally initiated cationic curing agents; the second component includes phenolic resin.

[0028] In this invention, the adhesive strength of the adhesive film can be significantly improved by adding a second component.

[0029] Preferably, the first component includes at least one latent curing agent.

[0030] Preferably, the latent curing agent includes at least a microcapsule-type latent curing agent.

[0031] In this invention, the latent curing agent also includes non-microencapsulated latent curing agents, such as imidazole non-microencapsulated latent curing agents, exemplarily selected from ADEKA's EH-5011, 5046S, 2110K, etc.

[0032] In this invention, the thermosetting temperature of the microencapsulated latent curing agent is above 90°C. The microencapsulated latent curing agent is classified according to its curing agent composition into imidazole-based, modified imidazole-based, amine-based, and modified amine-based room-temperature fast-reaction curing agents. The microencapsulated curing agent is a mixture pre-dispersed with liquid epoxy resin, such as Asahi Kasei's HXA3792, HXA3941HP, HXA3921HP, HXA3922, HXA3932HP, and HXA3042HP.

[0033] Preferably, the epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, tetraphenylethane epoxy resin, triphenylmethane epoxy resin, biphenyl-type epoxy resin, naphthyl ring-type epoxy resin, dicyclopentadiene-type epoxy resin, phosphorus-containing epoxy resin, nitrogen-containing epoxy resin, polyfunctional epoxy resin, isocyanate-type 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-type epoxy resin, chelated epoxy resin, or dendritic epoxy resin.

[0034] In this invention, the epoxy resin is preferably one or a mixture of several of the following: bisphenol A epoxy resin, bisphenol F epoxy resin, biphenyl-type epoxy resin, or naphthalene-type epoxy resin, which are solid at room temperature. The prepared adhesive film has better toughness and lower adhesive surface tack, and the lower adhesive surface tack gives the adhesive film better die-cutting performance.

[0035] Preferably, the filler comprises 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.

[0036] In this invention, adding too much filler will make it difficult to disperse the curing agent, especially microencapsulated latent curing agents, which are prone to losing their latent properties; adding too little filler will result in a large amount of adhesive overflow during hot pressing of the film.

[0037] In this invention, the filler can be surface-treated with a silane coupling agent, and can be directly added or pre-prepared into a filler dispersion or a paste and mixed with other components to obtain an epoxy resin composition.

[0038] In this invention, the filler preferably uses angular silica, spherical silica, or fumed silica. Compared with some alkaline fillers such as aluminum hydroxide and magnesium hydroxide, the resulting adhesive film exhibits higher high-temperature rapid reactivity. More preferably, the angular silica or spherical silica is a surface-treated filler, and the surface treatment agent can be a silane coupling agent. The silane coupling agent is preferably a silane coupling agent containing epoxy groups. After the silica filler is treated with an epoxy-containing silane coupling agent, the resulting adhesive film has superior adhesion properties, especially after damp heat aging.

[0039] In this invention, the filler comprises at least 1 to 10 parts of fumed silica, for example, 1 part, 2 parts, 4 parts, 6 parts, 8 parts, 10 parts, etc.

[0040] In this invention, for example, 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.

[0041] In this invention, the epoxy resin composition may further include flame retardants, tackifying resins, matting agents, and other modifiers as needed.

[0042] It should be noted that the content of each component in this invention, i.e., the "parts" mentioned, all refer to solid weight parts.

[0043] In this invention, the preparation method of the epoxy resin composition includes: mixing each component evenly.

[0044] 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 comprising the epoxy resin composition described in the first aspect.

[0045] In this invention, the thickness of the adhesive film can be determined according to actual needs, for example, it can be 5 to 20 μm.

[0046] Thirdly, the present invention provides a method for preparing the adhesive film described in the second aspect, the method comprising:

[0047] An epoxy resin composition is mixed with a solvent to obtain a resin solution; the resin solution is coated onto one surface of a release film and dried to obtain the film.

[0048] Preferably, the solid content of the resin solution is 20-40%.

[0049] Preferably, the drying temperature is 70–90°C and the drying time is 1–10 min.

[0050] In this invention, the solvent includes commonly used solvents such as toluene, butanone, acetone, ethyl acetate, and propylene glycol methyl ether, and is preferably one or a mixture of several of low-polarity toluene, ethyl acetate, and propylene glycol methyl ether.

[0051] In this invention, a protective film can be further laminated onto the surface of the epoxy pure adhesive film as needed.

[0052] Fourthly, the present invention provides a flexible circuit board, the flexible circuit board comprising the epoxy resin composition described in the first aspect or the adhesive film described in the second aspect.

[0053] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0054] The system refers to an equipment system, device system, or production device.

[0055] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0056] The epoxy resin composition provided by the present invention includes at least acrylate rubber as the toughening agent and a specific amount of polyarylate is added and compounded with other components. While ensuring that the film has excellent toughness and peel strength, it significantly reduces the damping loss factor of the film in the range of 0 to 100°C and improves the stability of the damping loss factor. At the same time, it also makes the film have a high elastic modulus, excellent room temperature storage stability and high temperature rapid reactivity. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the structure of the adhesive film of the present invention;

[0058] Wherein, 1-epoxy resin adhesive layer; 2-release film. Detailed Implementation

[0059] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0060] The materials used in all embodiments and comparative examples of this invention are as follows:

[0061] A1:YD011, Bisphenol A type epoxy resin, Guodu Chemical;

[0062] A2: YDF-2001, Bisphenol F type epoxy resin, Guodu Chemical;

[0063] B1:HXA3932, a mixture of curing agent and epoxy resin, manufactured by Asahi Kasei Corporation, Japan;

[0064] B2:SH6380, phenolic resin, Shandong Shengquan;

[0065] C1:SG-P3, acrylic rubber, epoxy value 0.21eq / Kg, Nagase, Japan;

[0066] C2:XER32, nitrile rubber, JSR Japan;

[0067] D1:L55, angular silica, Suzhou Jinyi;

[0068] D2:Q015, spherical silica, Suzhou Jinyi;

[0069] D3:R208, fumed silica, Evonik (Shanghai);

[0070] D4: BJM-AL1, aluminum hydroxide, betaine.

[0071] E1: Polyarylate U-100, UNIFINER Japan, Tg is 193℃, number average molecular weight 20,000-30,000;

[0072] E2: Polyarylate M-2040, UNIFINER Japan, Tg is 220℃, number average molecular weight 30000-40000.

[0073] Examples 1-8, Comparative Examples 1-2

[0074] Examples 1-8 and Comparative Examples 1-2 each provide an epoxy resin composition. The formulations of the epoxy resin compositions, based on solid weight parts, are shown in Tables 1-2; where " / " indicates that the component is not in the formulation.

[0075] Table 1

[0076]

[0077]

[0078] Table 2

[0079]

[0080] Application examples

[0081] A film, the structural schematic diagram of which is shown below. Figure 1 As shown, it includes an epoxy resin adhesive layer 1 and a release film 2 arranged sequentially; the epoxy resin adhesive layer includes epoxy resin compositions provided in Examples 1-8 and Comparative Examples 1-2 respectively; the preparation method of the film includes: mixing the epoxy resin composition with toluene to obtain a resin solution with a solid content of 30%; coating the resin solution onto one surface of the release film; and drying the solvent in the film using an oven at 80°C / 5min to prepare a pure film with a thickness of 10-15µm.

[0082] Performance testing

[0083] (1) Adhesive strength: FPC, SUS304 stainless steel plate, and pure epoxy film were cut into strips of 1cm×20cm. The pure epoxy film was stacked between the FPC and the SUS304 stainless steel plate, with the PI side of the FPC in contact with the epoxy pure epoxy film. After pressing at 180℃ / 30s / 4MPa, the strips were baked at 120℃ / 1hr. The peel strength between the FPC and the pure epoxy film was then tested, with a peel angle of 90° and a tensile rate of 100mm / min. The adhesive strength of the pure epoxy film was measured by the peel force. When the peel strength exceeded 15N / cm, the PI film would tear.

[0084] (2) Room temperature storage reaction rate: The reaction rate of epoxy groups was measured after the epoxy film was stored at room temperature for 15 days, compared to its initial state. This was used to evaluate the room temperature storage performance of the epoxy film. The lower the reaction rate of epoxy groups after a period of storage at room temperature, the better the room temperature storage performance of the epoxy film.

[0085] (3) High-temperature rapid reaction rate: After the epoxy film is baked at 180℃ for 30s, the reaction rate of the epoxy groups 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 groups, the better the high-temperature rapid reactivity of the epoxy film.

[0086] (4) Modulus and damping loss factor: The epoxy film was stacked to a thickness of 30 μm and baked at 180℃ / 30s+120℃ / 1hr. The modulus of the film at 50℃ and the maximum value of the damping loss factor in the range of 0-100℃ were tested by the DMA stretching method (temperature rise 10℃ / min, frequency 1Hz). The range of the damping loss factor in the range of 0-100℃ was also tested.

[0087] The specific test results are shown in Table 3.

[0088] Table 3

[0089]

[0090]

[0091] As shown in Table 3, the epoxy resin composition provided by the present invention produces a film with good stability at room temperature and good reactivity at high temperature, enabling rapid reaction. Furthermore, the film exhibits a low damping loss factor (≤0.1) and good stability of the damping loss factor (damping loss factor range ≤0.05 at 0-100℃) within the range of 0-100℃, as well as a high elastic modulus (≥1.4GPa). It also possesses high toughness and adhesive strength.

[0092] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are 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 within 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 epoxy resin, 30-100 parts curing agent, 30-100 parts toughening agent, 1-100 parts filler and 5-80 parts polyarylate; The toughening agent includes at least acrylate rubber; The number-average molecular weight of the polyarylate is 3000~50000; The glass transition temperature of the polyarylate is 100~300℃.

2. The epoxy resin composition according to claim 1, characterized in that, The polyarylate has the structure shown in Formula I: Equation I; In Formula I, R is selected from at least one of straight-chain or branched alkyl groups with ≥1 carbon atom, oxygen atom, or sulfoxide group; X may be the same or different, and each is independently selected from at least one of H, halogen, substituted or unsubstituted straight-chain or branched alkyl groups with ≥1 carbon atom.

3. The epoxy resin composition according to claim 1, characterized in that, The number-average molecular weight of the polyarylate is 10,000 to 35,000.

4. The epoxy resin composition according to claim 1, characterized in that, The glass transition temperature of the polyarylate is 200~300℃.

5. The epoxy resin composition according to claim 1, 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.

6. The epoxy resin composition according to claim 1, characterized in that, The toughening agent includes at least one of acrylate rubber, phenoxy resin, or nitrile rubber.

7. The epoxy resin composition according to claim 1, characterized in that, The curing agent comprises a first component, or the curing agent comprises a first component and a second component; The first component includes at least one of amine compounds, imidazole compounds, amide compounds, acid anhydride compounds, phenolic compounds, benzoxazine compounds, active ester compounds, and thermally initiated cationic curing agents; the second component includes phenolic resin.

8. The epoxy resin composition according to claim 7, characterized in that, The first component includes at least one latent curing agent.

9. The epoxy resin composition according to claim 8, characterized in that, The latent curing agent includes at least a microcapsule-type latent curing agent.

10. The epoxy resin composition according to claim 1, characterized in that, The epoxy resin includes at least one of the following: bisphenol A epoxy resin, bisphenol F epoxy resin, tetraphenylethane epoxy resin, triphenylmethane epoxy resin, biphenyl-type epoxy resin, naphthyl ring-type epoxy resin, dicyclopentadiene-type epoxy resin, phosphorus-containing epoxy resin, nitrogen-containing epoxy resin, isocyanate-type 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-type epoxy resin, chelated epoxy resin, or dendritic epoxy resin.

11. The epoxy resin composition according to claim 1, characterized in that, The filler includes at least one of the following: 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.

12. A film, characterized in that, The adhesive film includes 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 according to any one of claims 1 to 11.

13. A method for preparing an adhesive film according to claim 12, characterized in that, The preparation method includes: An epoxy resin composition is mixed with a solvent to obtain a resin solution; the resin solution is coated onto one surface of a release film and dried to obtain the film.

14. The preparation method according to claim 13, characterized in that, The solid content of the resin solution is 20-40%.

15. The preparation method according to claim 13, characterized in that, The drying temperature is 70~90℃, and the time is 1~10min.

16. A flexible circuit board, characterized in that, The flexible circuit board comprises the epoxy resin composition according to any one of claims 1 to 11 or the adhesive film according to claim 12.

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