Epoxy adhesive, preparation method and application thereof

Abstract

This invention discloses an epoxy adhesive, its preparation method, and its application. The epoxy adhesive comprises the following raw materials: epoxy resin, toughening agent, diluent, dispersant, defoamer, coupling agent, filler, fumed silica, carbon black, and curing agent. The epoxy adhesive has good fluidity before curing, maintains stability during dispensing, can quickly cover components on PCB boards, and cures rapidly at high temperatures without collapsing. It has high controllability and can significantly improve the production efficiency of electronic products.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, and specifically relates to an epoxy adhesive, its preparation method, and its application. Background Technology

[0002] With the rapid development of technology, electronic products are becoming smaller and more integrated, leading to an increasing demand for high-density PCB component integration in electronic devices such as mobile phone motherboards, smart wearables, and Bluetooth speakers. This, in turn, has led to higher performance requirements for adhesives that protect PCBs, especially in terms of adhesive flowability and specific curing conditions.

[0003] Existing single-component, low-viscosity epoxy adhesives, when applied to a PCB using a dispensing machine, can cover components in a designated area. However, after heat curing (130-140℃ for 10 minutes), the adhesive tends to flow, not only contaminating areas that shouldn't be covered but also reducing the overall adhesive thickness, potentially exposing components that were previously encapsulated in the adhesive. While some adhesive products can achieve a non-flowing effect, their high viscosity and thixotropy are detrimental to manufacturing processes and significantly reduce production efficiency.

[0004] Therefore, developing a low-viscosity, high-temperature, fast-curing epoxy adhesive that does not collapse or flow during the curing process is of research significance. It can keep up with the dispensing process of modern dispensing equipment, improve the production efficiency of electronic products, and has certain commercial value. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes an epoxy adhesive, its preparation method, and its application. This epoxy adhesive has good fluidity before curing, maintains stability during the dispensing process, can quickly cover components on PCB boards, and cures rapidly at high temperatures without collapsing. It has high controllability and can significantly improve the production efficiency of electronic products.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: An epoxy adhesive comprises the following raw materials: epoxy resin, toughening agent, diluent, dispersant, defoamer, coupling agent, filler, silica, carbon black and curing agent.

[0007] In some embodiments of the present invention, the epoxy adhesive comprises the following raw materials in parts by weight: epoxy resin: 41-63 parts; toughening agent: 2-12 parts; diluent: 13-26 parts; dispersant: 0.1-1 parts; defoamer: 0.1-1 parts; coupling agent: 0.1-0.2 parts; filler: 3-8 parts; fumed silica: 0.5-1 parts; carbon black: 0.5-4 parts; curing agent: 9-22 parts.

[0008] In some embodiments of the present invention, the epoxy resin is composed of a first epoxy resin and a second epoxy resin in a weight ratio of (40-60):(1-3), wherein the first epoxy resin is at least one of low viscosity bisphenol A epoxy resin and bisphenol F epoxy resin, and the second epoxy resin is a special epoxy resin with an alicyclic structure.

[0009] In some embodiments of the present invention, the bisphenol F epoxy resin is Zhilun ZLF-160H.

[0010] In some embodiments of the present invention, the epoxy equivalent of the second epoxy resin is 150-200, and the viscosity at 25°C is 200-250 cp.

[0011] In some embodiments of the present invention, the second epoxy resin is Adico EP-4088s.

[0012] In some embodiments of the present invention, the toughening agent is an epoxy resin core-shell rubber toughening agent.

[0013] In some embodiments of the present invention, the toughening agent is at least one of Zhongyuan Chemical MX-125, Zhongyuan Chemical MX-154 and Jinghan FX-940H.

[0014] In some embodiments of the present invention, the diluent is composed of a first diluent and a second diluent in a weight ratio of (10-18):(3-8), wherein the first diluent is at least one of p-tert-butylphenyl glycidyl ether and trimethylolpropane triglycidyl ether, and the second diluent is neodecanoic acid glycidyl ester.

[0015] In some embodiments of the present invention, the p-tert-butylphenyl glycidyl ether is ERISYSGE-11.

[0016] In some embodiments of the present invention, the neodecanoic acid glycidyl ester is Gadida JD-360XL.

[0017] In some embodiments of the present invention, the dispersant is a polyester dispersant.

[0018] In some embodiments of the present invention, the dispersant is Lianhong Dispersant S-315.

[0019] In some embodiments of the present invention, the defoamer is at least one of BYK-530, BYK-531 and BYK-1796 from Germany.

[0020] In some embodiments of the present invention, the coupling agent is Jianghan New Materials KH-560.

[0021] In some embodiments of the present invention, the gaseous silicon is Cabot TS-720.

[0022] In some embodiments of the present invention, the carbon black is Mitsubishi MA-100 from Japan.

[0023] In some embodiments of the present invention, the curing agent is a modified amine latent curing agent.

[0024] In some embodiments of the present invention, the curing agent is composed of a first curing agent and a second curing agent in a weight ratio of (9-17):(0-5), wherein the first curing agent includes at least one of Japanese Fuji FXR-1020 and FXR-1081, and the second curing agent includes at least one of Japanese Fuji FXR-1060cs and FXR-1070cs.

[0025] In some embodiments of the present invention, the filler is at least one of spherical silica powder and talc powder, and the particle size D50 of the filler is 3-10 μm.

[0026] In some embodiments of the present invention, the filler is Suzhou Lianrui's spherical silica micropowder NQ2120.

[0027] In some embodiments of the present invention, the raw materials further include 0.1-5 parts of rheology modifier, wherein the rheology modifier includes at least one of micronized polyamide wax and acrylic core-shell structured rheology modifier.

[0028] In some embodiments of the present invention, the micronized polyamide wax is crayvallacsl.

[0029] In some embodiments of the present invention, the acrylic core-shell rheology modifier is ZEFIACF351 from Japan.

[0030] In some embodiments of the present invention, the raw material further includes 0.1-0.5 parts of a curing accelerator, wherein the curing accelerator is at least one selected from 2-ethyl-4-methylimidazole and 1-cyanoethyl-2-ethyl-4-methylimidazole.

[0031] In some embodiments of the present invention, the 2-ethyl-4-methylimidazole is Shikoku Chemical 2E4MZ.

[0032] In some embodiments of the present invention, the 1-cyanoethyl-2-ethyl-4-methylimidazole is Yokoku Chemical 2E4MZ-CN.

[0033] A method for preparing the epoxy adhesive as described above includes the following steps: (1) The epoxy resin, toughening agent, diluent, dispersant, defoamer and coupling agent are mixed to obtain the first mixture; (2) The first mixture is mixed with filler, fumed silica and carbon black to obtain a second mixture; (3) The second mixture is mixed with the curing agent to obtain the epoxy adhesive.

[0034] In some embodiments of the present invention, in step (1), a rheology modifier is also added during the mixing process.

[0035] In some embodiments of the present invention, a curing accelerator is also added during the mixing process in step (3).

[0036] The application of epoxy adhesives in PCB component packaging as described above.

[0037] The beneficial effects of this invention are: (1) The epoxy adhesive of the present invention has good fluidity before curing and maintains stability during dispensing, and can quickly cover the components of the PCB board.

[0038] (2) The epoxy adhesive of the present invention will not collapse during high-temperature rapid curing, has high controllability, and can greatly improve the production efficiency of electronic products.

[0039] (3) After curing, the epoxy adhesive of the present invention is resistant to high temperature and high humidity. Under the double 85 aging test (85°C high temperature and 85% relative humidity), it can maintain good shear strength and has reliability. Detailed Implementation

[0040] The present invention will be further described below with reference to specific embodiments.

[0041] Example 1: An epoxy adhesive comprises the following raw materials in parts by weight: a first epoxy resin: 43 parts; a second epoxy resin: 2.5 parts; a toughening agent: 11 parts; a first diluent: 13 parts; a second diluent: 5 parts; a dispersant: 0.5 parts; a defoamer: 0.5 parts; a coupling agent: 0.2 parts; a rheology modifier: 3 parts; a filler: 4.5 parts; fumed silica: 1 part; carbon black: 0.1 parts; and a first curing agent: 15.7 parts. The first epoxy resin is bisphenol F epoxy resin, the second epoxy resin is a special epoxy resin with an alicyclic structure, the toughening agent is an epoxy resin core-shell rubber toughening agent, the first diluent is p-tert-butylphenyl glycidyl ether, the second diluent is neodecanoic acid glycidyl ester, the dispersant is a polyester dispersant, the filler is spherical silica powder, the rheology modifier is micronized polyamide wax, and the first curing agent is a modified amine latent curing agent.

[0042] The specific raw materials are as follows: the first epoxy resin is Zhilun ZLF-160H; the second epoxy resin is Aidi Ke EP-4088s; the toughening agent is Zhongyuan Chemical MX-125; the first diluent is ERISYS GE-11; the second diluent is Jiadida JD-360XL; the dispersant is Lianhong Dispersant S-315; the defoamer is German BYK-530; the coupling agent is Jianghan New Materials KH-560; the rheology modifier is Crayvallac SL; the filler is Suzhou Lianrui Spherical Silica Powder NQ2120; the fumed silica is Cabot TS-720; the carbon black is Mitsubishi MA-100; and the first curing agent is Fuji FXR-1020. The preparation method of the above-mentioned epoxy adhesive includes the following steps: (1) First, the first epoxy resin, the second epoxy resin, the toughening agent, the first diluent, the second diluent, the dispersant, the defoamer, the coupling agent, and the rheology modifier are mixed in a planetary gravity mixer to prepare a first mixture (speed 1000 rpm / 2 min); (2) Then the filler, fumed silica and carbon black were added to the first mixture and mixed with a planetary gravity mixer to prepare the second mixture (1000 rpm / 3 min). (3) After the second mixture is cooled at room temperature for 10 minutes, the first curing agent is added to the second mixture and mixed once with a planetary gravity mixer (600 rpm / 3 min). After being cooled at room temperature for 10 minutes, it is mixed a second time with a planetary gravity mixer under vacuum (600 rpm / 3 min) to obtain the epoxy adhesive, which is then refrigerated at -15~-25℃.

[0043] Example 2: An epoxy adhesive comprises the following raw materials in parts by weight: a first epoxy resin: 43 parts; a second epoxy resin: 2.5 parts; a toughening agent: 11 parts; a first diluent: 13 parts; a second diluent: 5 parts; a dispersant: 0.5 parts; a defoamer: 0.5 parts; a coupling agent: 0.2 parts; a rheology modifier: 3 parts; a filler: 4.5 parts; fumed silica: 1 part; carbon black: 0.1 parts; and a first curing agent: 15.7 parts. The first epoxy resin is bisphenol F epoxy resin, the second epoxy resin is a special epoxy resin with an alicyclic structure, the toughening agent is an epoxy resin core-shell rubber toughening agent, the first diluent is p-tert-butylphenyl glycidyl ether, the second diluent is neodecanoic acid glycidyl ester, the dispersant is a polyester dispersant, the filler is spherical silica powder, the rheology modifier is an acrylic core-shell structure rheology modifier, and the first curing agent is a modified amine latent curing agent.

[0044] The specific raw materials are as follows: the first epoxy resin is Zhilun ZLF-160H; the second epoxy resin is Aidi Ke EP-4088s; the toughening agent is Zhongyuan Chemical MX-125; the first diluent is ERISYS GE-11; the second diluent is Jiadida JD-360XL; the dispersant is Lianhong Dispersant S-315; the defoamer is German BYK-530; the coupling agent is Jianghan New Materials KH-560; the rheology modifier is Japanese ZEFIAC F351; the filler is Suzhou Lianrui spherical silica powder NQ2120; the fumed silica is Cabot TS-720; the carbon black is Japanese Mitsubishi MA-100; and the first curing agent is Japanese Fuji FXR-1020. The preparation method of the above-mentioned epoxy adhesive includes the following steps: (1) First, the first epoxy resin, the second epoxy resin, the toughening agent, the first diluent, the second diluent, the dispersant, the defoamer, the coupling agent, and the rheology modifier are mixed in a planetary gravity mixer to prepare a first mixture (speed 1000 rpm / 2 min); (2) Then the filler, fumed silica and carbon black were added to the first mixture and mixed with a planetary gravity mixer to prepare the second mixture (1000 rpm / 3 min). (3) After the second mixture is cooled at room temperature for 10 minutes, the first curing agent is added to the second mixture and mixed once with a planetary gravity mixer (600 rpm / 3 min). After being cooled at room temperature for 10 minutes, it is mixed a second time with a planetary gravity mixer under vacuum (600 rpm / 3 min) to obtain the epoxy adhesive, which is then refrigerated at -15~-25℃.

[0045] Example 3: An epoxy adhesive comprises the following raw materials in parts by weight: a first epoxy resin: 43 parts; a second epoxy resin: 2.5 parts; a toughening agent: 11 parts; a first diluent: 13 parts; a second diluent: 5 parts; a dispersant: 0.5 parts; a defoamer: 0.5 parts; a coupling agent: 0.2 parts; a rheology modifier: 3 parts; a filler: 4.5 parts; fumed silica: 1 part; carbon black: 0.1 parts; and a first curing agent: 15.7 parts. The first epoxy resin is bisphenol F epoxy resin, the second epoxy resin is a special epoxy resin with an alicyclic structure, the toughening agent is an epoxy resin core-shell rubber toughening agent, the first diluent is p-tert-butylphenyl glycidyl ether, the second diluent is neodecanoic acid glycidyl ester, the dispersant is a polyester dispersant, the filler is spherical silica powder, the rheology modifier is an acrylic core-shell structure rheology modifier, and the first curing agent is a modified amine latent curing agent.

[0046] The specific raw materials are as follows: the first epoxy resin is Zhilun ZLF-160H; the second epoxy resin is Aidi Ke EP-4088s; the toughening agent is Zhongyuan Chemical MX-125; the first diluent is ERISYS GE-11; the second diluent is Jiadida JD-360XL; the dispersant is Lianhong Dispersant S-315; the defoamer is German BYK-530; the coupling agent is Jianghan New Materials KH-560; the rheology modifier is Japanese ZEFIAC F351; the filler is Suzhou Lianrui spherical silica powder NQ2120; the fumed silica is Cabot TS-720; the carbon black is Japanese Mitsubishi MA-100; and the first curing agent is Japanese Fuji FXR-1081. The preparation method of the above-mentioned epoxy adhesive includes the following steps: (1) First, the first epoxy resin, the second epoxy resin, the toughening agent, the first diluent, the second diluent, the dispersant, the defoamer, the coupling agent, and the rheology modifier are mixed in a planetary gravity mixer to prepare a first mixture (speed 1000 rpm / 2 min); (2) Then the filler, fumed silica and carbon black were added to the first mixture and mixed with a planetary gravity mixer to prepare the second mixture (1000 rpm / 3 min). (3) After the second mixture is cooled at room temperature for 10 minutes, the first curing agent is added to the second mixture and mixed once with a planetary gravity mixer (600 rpm / 3 min). After being cooled at room temperature for 10 minutes, it is mixed a second time with a planetary gravity mixer under vacuum (600 rpm / 3 min) to obtain the epoxy adhesive, which is then refrigerated at -15~-25℃.

[0047] Example 4: An epoxy adhesive comprises the following raw materials in parts by weight: a first epoxy resin: 42 parts; a second epoxy resin: 2.5 parts; a toughening agent: 11 parts; a first diluent: 13 parts; a second diluent: 5 parts; a dispersant: 0.5 parts; a defoamer: 0.5 parts; a coupling agent: 0.2 parts; a rheology modifier: 5 parts; a filler: 3.5 parts; fumed silica: 1 part; carbon black: 0.1 parts; and a first curing agent: 15.7 parts. The first epoxy resin is bisphenol F epoxy resin, the second epoxy resin is a special epoxy resin with an alicyclic structure, the toughening agent is an epoxy resin core-shell rubber toughening agent, the first diluent is p-tert-butylphenyl glycidyl ether, the second diluent is neodecanoic acid glycidyl ester, the dispersant is a polyester dispersant, the filler is spherical silica powder, the rheology modifier is an acrylic core-shell structure rheology modifier, and the first curing agent is a modified amine latent curing agent.

[0048] The specific raw materials are as follows: the first epoxy resin is Zhilun ZLF-160H; the second epoxy resin is Aidi Ke EP-4088s; the toughening agent is Zhongyuan Chemical MX-125; the first diluent is ERISYS GE-11; the second diluent is Jiadida JD-360XL; the dispersant is Lianhong Dispersant S-315; the defoamer is German BYK-530; the coupling agent is Jianghan New Materials KH-560; the rheology modifier is Japanese ZEFIAC F351; the filler is Suzhou Lianrui spherical silica powder NQ2120; the fumed silica is Cabot TS-720; the carbon black is Japanese Mitsubishi MA-100; and the first curing agent is Japanese Fuji FXR-1081. The preparation method of the above-mentioned epoxy adhesive includes the following steps: (1) First, the first epoxy resin, the second epoxy resin, the toughening agent, the first diluent, the second diluent, the dispersant, the defoamer, the coupling agent, and the rheology modifier are mixed in a planetary gravity mixer to prepare a first mixture (speed 1000 rpm / 2 min); (2) Then the filler, fumed silica and carbon black were added to the first mixture and mixed with a planetary gravity mixer to prepare the second mixture (1000 rpm / 3 min). (3) After the second mixture is cooled at room temperature for 10 minutes, the first curing agent is added to the second mixture and mixed once with a planetary gravity mixer (600 rpm / 3 min). After being cooled at room temperature for 10 minutes, it is mixed a second time with a planetary gravity mixer under vacuum (600 rpm / 3 min) to obtain the epoxy adhesive, which is then refrigerated at -15~-25℃.

[0049] Example 5: An epoxy adhesive comprises the following raw materials in parts by weight: a first epoxy resin: 43 parts; a second epoxy resin: 2.5 parts; a toughening agent: 11 parts; a first diluent: 13 parts; a second diluent: 5 parts; a dispersant: 0.5 parts; a defoamer: 0.5 parts; a coupling agent: 0.2 parts; a filler: 4.5 parts; fumed silica: 1 part; carbon black: 3.5 parts; a first curing agent: 12 parts; a second curing agent: 2.8 parts; and an accelerator: 0.5 parts. The first epoxy resin is bisphenol F epoxy resin, the second epoxy resin is a special epoxy resin with an alicyclic structure, the toughening agent is an epoxy resin core-shell rubber toughening agent, the first diluent is p-tert-butylphenyl glycidyl ether, the second diluent is neodecanoic acid glycidyl ester, the dispersant is a polyester dispersant, the filler is spherical silica powder, the first and second curing agents are modified amine latent curing agents, and the accelerator is 2-ethyl-4-methylimidazole.

[0050] The specific raw materials are as follows: the first epoxy resin is Zhilun ZLF-160H; the second epoxy resin is Aidi Ke EP-4088s; the toughening agent is Zhongyuan Chemical MX-125; the first diluent is ERISYS GE-11; the second diluent is Jiadida JD-360XL; the dispersant is Lianhong Dispersant S-315; the defoamer is German BYK-530; the coupling agent is Jianghan New Materials KH-560; the filler is Suzhou Lianrui Spherical Silica Powder NQ2120; the fumed silica is Cabot TS-720; the carbon black is Mitsubishi MA-100; the first curing agent is Japanese Fuji FXR-1081; the second curing agent is Japanese Fuji FXR-1060CS; and the accelerator is Shikoku Chemical 2E4MZ. The preparation method of the above-mentioned epoxy adhesive includes the following steps: (1) First, the first epoxy resin, the second epoxy resin, the toughening agent, the first diluent, the second diluent, the dispersant, the defoamer, and the coupling agent are mixed in a planetary gravity mixer to prepare a first mixture (speed 1000 rpm / 2 min); (2) Then the filler, fumed silica and carbon black were added to the first mixture and mixed with a planetary gravity mixer to prepare the second mixture (1000 rpm / 3 min). (3) After the second mixture is cooled at room temperature for 10 minutes, the first curing agent, the second curing agent and the accelerator are added to the second mixture and mixed once with a planetary gravity mixer (600 rpm / 3 min). After being cooled at room temperature for 10 minutes, it is mixed a second time with a planetary gravity mixer under vacuum (600 rpm / 3 min) to obtain the epoxy adhesive, which is then refrigerated at -15~-25℃.

[0051] Example 6: An epoxy adhesive comprises the following raw materials in parts by weight: a first epoxy resin: 43 parts; a second epoxy resin: 2.5 parts; a toughening agent: 11 parts; a first diluent: 13 parts; a second diluent: 5 parts; a dispersant: 0.5 parts; a defoamer: 0.5 parts; a coupling agent: 0.2 parts; a filler: 4.5 parts; fumed silica: 1 part; carbon black: 3.5 parts; a first curing agent: 12 parts; a second curing agent: 2.8 parts; and an accelerator: 0.5 parts. The first epoxy resin is bisphenol F epoxy resin, the second epoxy resin is a special epoxy resin with an alicyclic structure, the toughening agent is an epoxy resin core-shell rubber toughening agent, the first diluent is p-tert-butylphenyl glycidyl ether, the second diluent is neodecanoic acid glycidyl ester, the dispersant is a polyester dispersant, the filler is spherical silica powder, the first and second curing agents are modified amine latent curing agents, and the accelerator is 2-ethyl-4-methylimidazole.

[0052] The specific raw materials are as follows: the first epoxy resin is Zhilun ZLF-160H; the second epoxy resin is Aidi Ke EP-4088s; the toughening agent is Zhongyuan Chemical MX-125; the first diluent is ERISYS GE-11; the second diluent is Jiadida JD-360XL; the dispersant is Lianhong Dispersant S-315; the defoamer is German BYK-530; the coupling agent is Jianghan New Materials KH-560; the filler is Suzhou Lianrui Spherical Silica Powder NQ2120; the fumed silica is Cabot TS-720; the carbon black is Mitsubishi MA-100; the first curing agent is Japanese Fuji FXR-1081; the second curing agent is Japanese Fuji FXR-1070CS; and the accelerator is Shikoku Chemical 2E4MZ. The preparation method of the above-mentioned epoxy adhesive includes the following steps: (1) First, the first epoxy resin, the second epoxy resin, the toughening agent, the first diluent, the second diluent, the dispersant, the defoamer, and the coupling agent are mixed in a planetary gravity mixer to prepare a first mixture (speed 1000 rpm / 2 min); (2) Then the filler, fumed silica and carbon black were added to the first mixture and mixed with a planetary gravity mixer to prepare the second mixture (1000 rpm / 3 min). (3) After the second mixture is cooled at room temperature for 10 minutes, the first curing agent, the second curing agent and the accelerator are added to the second mixture and mixed once with a planetary gravity mixer (600 rpm / 3 min). After being cooled at room temperature for 10 minutes, it is mixed a second time with a planetary gravity mixer under vacuum (600 rpm / 3 min) to obtain the epoxy adhesive, which is then refrigerated at -15~-25℃.

[0053] Example 7: An epoxy adhesive comprises the following raw materials in parts by weight: a first epoxy resin: 43 parts; a second epoxy resin: 2.5 parts; a toughening agent: 11 parts; a first diluent: 13 parts; a second diluent: 5 parts; a dispersant: 0.5 parts; a defoamer: 0.5 parts; a coupling agent: 0.2 parts; a filler: 4.5 parts; fumed silica: 1 part; carbon black: 3.5 parts; a first curing agent: 9.8 parts; a second curing agent: 5 parts; and an accelerator: 0.5 parts. The first epoxy resin is bisphenol F epoxy resin, the second epoxy resin is a special epoxy resin with an alicyclic structure, the toughening agent is an epoxy resin core-shell rubber toughening agent, the first diluent is p-tert-butylphenyl glycidyl ether, the second diluent is neodecanoic acid glycidyl ester, the dispersant is a polyester dispersant, the filler is spherical silica powder, the first and second curing agents are modified amine latent curing agents, and the accelerator is 2-ethyl-4-methylimidazole.

[0054] The specific raw materials are as follows: the first epoxy resin is Zhilun ZLF-160H; the second epoxy resin is Aidi Ke EP-4088s; the toughening agent is Zhongyuan Chemical MX-125; the first diluent is ERISYS GE-11; the second diluent is Jiadida JD-360XL; the dispersant is Lianhong Dispersant S-315; the defoamer is German BYK-530; the coupling agent is Jianghan New Materials KH-560; the filler is Suzhou Lianrui Spherical Silica Powder NQ2120; the fumed silica is Cabot TS-720; the carbon black is Mitsubishi MA-100; the first curing agent is Japanese Fuji FXR-1081; the second curing agent is Japanese Fuji FXR-1060CS; and the accelerator is Shikoku Chemical 2E4MZ. The preparation method of the above-mentioned epoxy adhesive includes the following steps: (1) First, the first epoxy resin, the second epoxy resin, the toughening agent, the first diluent, the second diluent, the dispersant, the defoamer, and the coupling agent are mixed in a planetary gravity mixer to prepare a first mixture (speed 1000 rpm / 2 min); (2) Then the filler, fumed silica and carbon black were added to the first mixture and mixed with a planetary gravity mixer to prepare the second mixture (1000 rpm / 3 min). (3) After the second mixture is cooled at room temperature for 10 minutes, the first curing agent, the second curing agent and the accelerator are added to the second mixture and mixed once with a planetary gravity mixer (600 rpm / 3 min). After being cooled at room temperature for 10 minutes, it is mixed a second time with a planetary gravity mixer under vacuum (600 rpm / 3 min) to obtain the epoxy adhesive, which is then refrigerated at -15~-25℃.

[0055] Example 8: An epoxy adhesive comprises the following raw materials in parts by weight: a first epoxy resin: 43 parts; a second epoxy resin: 2.5 parts; a toughening agent: 11 parts; a first diluent: 13 parts; a second diluent: 5 parts; a dispersant: 0.5 parts; a defoamer: 0.5 parts; a coupling agent: 0.2 parts; a filler: 5.5 parts; fumed silica: 1.5 parts; carbon black: 2 parts; a first curing agent: 12 parts; a second curing agent: 2.8 parts; and an accelerator: 0.5 parts. The first epoxy resin is bisphenol F epoxy resin, the second epoxy resin is a special epoxy resin with an alicyclic structure, the toughening agent is an epoxy resin core-shell rubber toughening agent, the first diluent is p-tert-butylphenyl glycidyl ether, the second diluent is neodecanoic acid glycidyl ester, the dispersant is a polyester dispersant, the filler is spherical silica powder, the first and second curing agents are modified amine latent curing agents, and the accelerator is 2-ethyl-4-methylimidazole.

[0056] The specific raw materials are as follows: the first epoxy resin is Zhilun ZLF-160H; the second epoxy resin is Aidi Ke EP-4088s; the toughening agent is Zhongyuan Chemical MX-125; the first diluent is ERISYS GE-11; the second diluent is Jiadida JD-360XL; the dispersant is Lianhong Dispersant S-315; the defoamer is German BYK-530; the coupling agent is Jianghan New Materials KH-560; the filler is Suzhou Lianrui Spherical Silica Powder NQ2120; the fumed silica is Cabot TS-720; the carbon black is Mitsubishi MA-100; the first curing agent is Japanese Fuji FXR-1081; the second curing agent is Japanese Fuji FXR-1070CS; and the accelerator is Shikoku Chemical 2E4MZ. The preparation method of the above-mentioned epoxy adhesive includes the following steps: (1) First, the first epoxy resin, the second epoxy resin, the toughening agent, the first diluent, the second diluent, the dispersant, the defoamer, and the coupling agent are mixed in a planetary gravity mixer to prepare a first mixture (speed 1000 rpm / 2 min); (2) Then the filler, fumed silica and carbon black were added to the first mixture and mixed with a planetary gravity mixer to prepare the second mixture (1000 rpm / 3 min). (3) After the second mixture is cooled at room temperature for 10 minutes, the first curing agent, the second curing agent and the accelerator are added to the second mixture and mixed once with a planetary gravity mixer (600 rpm / 3 min). After being cooled at room temperature for 10 minutes, it is mixed a second time with a planetary gravity mixer under vacuum (600 rpm / 3 min) to obtain the epoxy adhesive, which is then refrigerated at -15~-25℃.

[0057] Example 9: An epoxy adhesive comprises the following raw materials in parts by weight: a first epoxy resin: 43 parts; a second epoxy resin: 2.5 parts; a toughening agent: 11 parts; a first diluent: 13 parts; a second diluent: 5 parts; a dispersant: 0.5 parts; a defoamer: 0.5 parts; a coupling agent: 0.2 parts; a filler: 5 parts; fumed silica: 1 part; carbon black: 3.5 parts; a first curing agent: 12 parts; and a second curing agent: 2.8 parts; wherein the first epoxy resin is bisphenol F epoxy resin, the second epoxy resin is a special epoxy resin with an alicyclic structure, the toughening agent is an epoxy resin core-shell rubber toughening agent, the first diluent is p-tert-butylphenyl glycidyl ether, the second diluent is neodecanoic acid glycidyl ester, the dispersant is a polyester dispersant, the filler is spherical silica powder, and the first and second curing agents are modified amine latent curing agents.

[0058] The specific raw materials are as follows: the first epoxy resin is Zhilun ZLF-160H; the second epoxy resin is Aidi Ke EP-4088s; the toughening agent is Zhongyuan Chemical MX-125; the first diluent is ERISYS GE-11; the second diluent is Jiadida JD-360XL; the dispersant is Lianhong Dispersant S-315; the defoamer is German BYK-530; the coupling agent is Jianghan New Materials KH-560; the filler is Suzhou Lianrui Spherical Silica Powder NQ2120; the fumed silica is Cabot TS-720; the carbon black is Mitsubishi MA-100; the first curing agent is Japanese Fuji FXR-1081; the second curing agent is Japanese Fuji FXR-1070CS; and the accelerator is Shikoku Chemical 2E4MZ. The preparation method of the above-mentioned epoxy adhesive includes the following steps: (1) First, the first epoxy resin, the second epoxy resin, the toughening agent, the first diluent, the second diluent, the dispersant, the defoamer, and the coupling agent are mixed in a planetary gravity mixer to prepare a first mixture (speed 1000 rpm / 2 min); (2) Then the filler, fumed silica and carbon black were added to the first mixture and mixed with a planetary gravity mixer to prepare the second mixture (1000 rpm / 3 min). (3) After the second mixture is cooled at room temperature for 10 minutes, the first curing agent and the second curing agent are added to the second mixture and mixed once with a planetary gravity mixer (600 rpm / 3 min). After being cooled at room temperature for 10 minutes, the mixture is mixed a second time with a planetary gravity mixer under vacuum (600 rpm / 3 min) to obtain the epoxy adhesive, which is then refrigerated at -15~-25℃.

[0059] Example 10: An epoxy adhesive comprises the following raw materials in parts by weight: a first epoxy resin: 42 parts; a second epoxy resin: 2.5 parts; a toughening agent: 11 parts; a first diluent: 13 parts; a second diluent: 5 parts; a dispersant: 0.5 parts; a defoamer: 0.5 parts; a coupling agent: 0.2 parts; a filler: 4.5 parts; fumed silica: 0.5 parts; carbon black: 5 parts; a first curing agent: 12 parts; a second curing agent: 2.8 parts; and an accelerator: 0.5 parts. The first epoxy resin is bisphenol F epoxy resin, the second epoxy resin is a special epoxy resin with an alicyclic structure, the toughening agent is an epoxy resin core-shell rubber toughening agent, the first diluent is p-tert-butylphenyl glycidyl ether, the second diluent is neodecanoic acid glycidyl ester, the dispersant is a polyester dispersant, the filler is spherical silica powder, the first and second curing agents are modified amine latent curing agents, and the accelerator is 2-ethyl-4-methylimidazole.

[0060] The specific raw materials are as follows: the first epoxy resin is Zhilun ZLF-160H; the second epoxy resin is Aidi Ke EP-4088s; the toughening agent is Zhongyuan Chemical MX-125; the first diluent is ERISYS GE-11; the second diluent is Jiadida JD-360XL; the dispersant is Lianhong Dispersant S-315; the defoamer is German BYK-530; the coupling agent is Jianghan New Materials KH-560; the filler is Suzhou Lianrui Spherical Silica Powder NQ2120; the fumed silica is Cabot TS-720; the carbon black is Mitsubishi MA-100; the first curing agent is Japanese Fuji FXR-1081; the second curing agent is Japanese Fuji FXR-1070CS; and the accelerator is Shikoku Chemical 2E4MZ. The preparation method of the above-mentioned epoxy adhesive includes the following steps: (1) First, the first epoxy resin, the second epoxy resin, the toughening agent, the first diluent, the second diluent, the dispersant, the defoamer, and the coupling agent are mixed in a planetary gravity mixer to prepare a first mixture (speed 1000 rpm / 2 min); (2) Then the filler, fumed silica and carbon black were added to the first mixture and mixed with a planetary gravity mixer to prepare the second mixture (1000 rpm / 3 min). (3) After the second mixture is cooled at room temperature for 10 minutes, the first curing agent, the second curing agent and the accelerator are added to the second mixture and mixed once with a planetary gravity mixer (600 rpm / 3 min). After being cooled at room temperature for 10 minutes, it is mixed a second time with a planetary gravity mixer under vacuum (600 rpm / 3 min) to obtain the epoxy adhesive, which is then refrigerated at -15~-25℃.

[0061] Example 11: An epoxy adhesive comprises the following raw materials in parts by weight: a first epoxy resin: 46 parts; a second epoxy resin: 2.5 parts; a toughening agent: 6 parts; a first diluent: 13 parts; a second diluent: 5 parts; a dispersant: 0.5 parts; a defoamer: 0.5 parts; a coupling agent: 0.2 parts; a filler: 6.5 parts; fumed silica: 1 part; carbon black: 3.5 parts; a first curing agent: 12 parts; a second curing agent: 2.8 parts; and an accelerator: 0.5 parts. The first epoxy resin is bisphenol F epoxy resin, the second epoxy resin is a special epoxy resin with an alicyclic structure, the toughening agent is an epoxy resin core-shell rubber toughening agent, the first diluent is p-tert-butylphenyl glycidyl ether, the second diluent is neodecanoic acid glycidyl ester, the dispersant is a polyester dispersant, the filler is spherical silica powder, the first and second curing agents are modified amine latent curing agents, and the accelerator is 2-ethyl-4-methylimidazole.

[0062] The specific raw materials are as follows: the first epoxy resin is Zhilun ZLF-160H; the second epoxy resin is Aidi Ke EP-4088s; the toughening agent is Zhongyuan Chemical MX-125; the first diluent is ERISYS GE-11; the second diluent is Jiadida JD-360XL; the dispersant is Lianhong Dispersant S-315; the defoamer is German BYK-530; the coupling agent is Jianghan New Materials KH-560; the filler is Suzhou Lianrui Spherical Silica Powder NQ2120; the fumed silica is Cabot TS-720; the carbon black is Mitsubishi MA-100; the first curing agent is Japanese Fuji FXR-1081; the second curing agent is Japanese Fuji FXR-1070CS; and the accelerator is Shikoku Chemical 2E4MZ. The preparation method of the above-mentioned epoxy adhesive includes the following steps: (1) First, the first epoxy resin, the second epoxy resin, the toughening agent, the first diluent, the second diluent, the dispersant, the defoamer, and the coupling agent are mixed in a planetary gravity mixer to prepare a first mixture (speed 1000 rpm / 2 min); (2) Then the filler, fumed silica and carbon black were added to the first mixture and mixed with a planetary gravity mixer to prepare the second mixture (1000 rpm / 3 min). (3) After the second mixture is cooled at room temperature for 10 minutes, the first curing agent, the second curing agent and the accelerator are added to the second mixture and mixed once with a planetary gravity mixer (600 rpm / 3 min). After being cooled at room temperature for 10 minutes, it is mixed a second time with a planetary gravity mixer under vacuum (600 rpm / 3 min) to obtain the epoxy adhesive, which is then refrigerated at -15~-25℃.

[0063] The specific formulation ratios for Examples 1-11 are shown in Table 1 below.

[0064] Table 1. Specific formulation ratios for each example.

[0065] Experimental example: The performance of the epoxy adhesives prepared in Examples 1-11 of this invention was tested.

[0066] Sample Preparation: 1. After thawing the prepared epoxy adhesive at room temperature for 2 hours, apply it to a PCB solder mask (green solder mask). Construct a shearing strip with a coating area of ​​25mm × 10mm. Then place it in an oven and cure at 120℃ for 30 minutes. Prepare the shearing strip according to GB / T7124-2008 standard. 2. Use a dropper to draw 0.10g of the thawed adhesive and add it to the solder mask PCB. After standing for 10 minutes, measure the maximum width of the adhesive dot. Then place it in a 130℃ oven for 10 minutes and measure the maximum width of the adhesive. Record the width change rate before and after curing. The PCB solder mask size mentioned in the sample is 25mm × 100mm.

[0067] Test method: 1. Viscosity test: The test equipment was Brookfield CAP2000+L, and the test conditions were 7# 50rpm@(25±1)℃ and 7# 50rpm@(25±1)℃. The thixotropic viscosity was the ratio of the viscosity at 5rpm to that at 50rpm. The test standard was GB / T 2794-2022.

[0068] 2. Moisture and heat resistance: After curing, the sheared specimens were placed in an 85℃ / 85%RH (double 85) oven for 240 hours of aging and then removed. The shear strength at room temperature was measured, referring to the GB / T 7124-2008 standard for shear strength testing.

[0069] 3. Visually inspect the appearance of the adhesive dots on the PCB after curing, including color and the number of surface pores (for the surface pore test, the amount of adhesive is about 0.15g). Measure the width of the adhesive with calipers and record the width change rate before and after curing.

[0070] 4. Dispense a portion of the adhesive into a 50mL tube and apply it to the PCB with components using an automatic dispensing machine. Some parameters include: nozzle orifice diameter 0.1mm, and ejector pin diameter 1.5mm. Observe the appearance after curing at 130℃ for 10 minutes, recording the extent of adhesive coverage on the PCB, whether there is overflow or contamination, and whether the PCB has collapsed and exposed components.

[0071] The experimental results are shown in Table 2.

[0072] Table 2: Performance Test Results of Epoxy Adhesives

[0073] The results in Table 2 show that: Examples 1-4 verified the effect of two rheology modifiers on the width change rate. It can be seen that the F-351 rheology modifier can play a role in preventing collapse, but the appearance after curing is gray-black, which may be due to some incompatible substances. Comparing Example 2 and Example 3, it can be concluded that the cured appearance using curing agent FXR-1081 is superior to that using curing agent FXR-1020, with a reduction in the number of surface pores.

[0074] Examples 5-8 show that the addition of the accelerator can improve the shear strength of the adhesive.

[0075] A comparison of Example 5 and Example 4 shows that the amount of carbon black MA-100 added has a significant impact on the width change rate, decreasing it from 10.4% to 4.3%. Subsequent Examples 6 and 7 also corroborate this result.

[0076] In Examples 5 and 7, the curing agent FXR-1060CS was used, which affected the cured appearance, changing it from glossy to matte, as in Example 6.

[0077] Compared with Example 6, Example 8 increased the content of fumed silica and decreased the amount of carbon black. It was found that even with increased thixotropy, glue overflow occurred after curing, and the width change rate also increased to 13.1%. This further illustrates that carbon black plays a crucial role in anti-collapse properties. Compared with Example 6, Example 9 shows that the shear strength decreased after the accelerator was removed. The accelerator is essential for accelerating curing. Compared with Example 6, Example 10 further increased the amount of carbon black. Although other properties were not significantly affected, especially since the effect of carbon black on thixotropy is much smaller than that of gaseous silicon, agglomeration occurred during the preparation of Example 10. Therefore, after curing, defects appeared in the appearance and more bubbles appeared. Compared to Example 6, Example 11 reduced the amount of toughening agent, but the shear strength decreased significantly. This demonstrates that appropriate toughening is beneficial for the adhesion of adhesives to PCB sheets.

[0078] All embodiments underwent double 85 aging tests, and all performed excellently overall.

[0079] The epoxy adhesives of Examples 5-7 have a viscosity of no more than 3972 cp at 7# 5 rpm and no more than 1986 cp at 7# 50 rpm. The thixotropy does not exceed 2.0, and the shear strength at room temperature can reach 12.5 MPa or above. After the double 85 aging test, the shear strength at room temperature can reach 11.1 MPa or above. Moreover, there will be no leakage of components or overflow of adhesive when using a dispensing machine. In summary, Example 6 is the best choice, which has the best appearance and dispensing effect while ensuring that the thixotropy does not exceed 2.0.

[0080] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An epoxy adhesive, characterized in that: It includes the following raw materials: epoxy resin, toughening agent, diluent, dispersant, defoamer, coupling agent, filler, silica, carbon black and curing agent.

2. The epoxy adhesive according to claim 1, characterized in that: The raw materials include the following parts by weight: epoxy resin: 41-63 parts; Toughening agent: 2-12 parts; Diluent: 13-26 parts; Dispersant: 0.1-1 part; Defoamer: 0.1-1 part; Coupling agent: 0.1-0.2 parts; Filler: 3-8 parts; Gas-containing silicon: 0.5-1 part; Carbon black: 0.5-4 parts; Curing agent: 9-22 parts.

3. The epoxy adhesive according to claim 1, characterized in that: The epoxy resin is composed of a first epoxy resin and a second epoxy resin in a weight ratio of (40-60):(1-3). The first epoxy resin is at least one of low-viscosity bisphenol A epoxy resin and bisphenol F epoxy resin, and the second epoxy resin is a special epoxy resin with an alicyclic structure.

4. The epoxy adhesive according to claim 1, characterized in that: The toughening agent is an epoxy resin core-shell rubber toughening agent.

5. The epoxy adhesive according to claim 1, characterized in that: The diluent is composed of a first diluent and a second diluent in a weight ratio of (10-18):(3-8), wherein the first diluent is at least one of p-tert-butylphenyl glycidyl ether and trimethylolpropane triglycidyl ether, and the second diluent is neodecanoic acid glycidyl ester.

6. The epoxy adhesive according to claim 1, characterized in that: The curing agent is composed of a first curing agent and a second curing agent in a weight ratio of (9-17):(0-5), wherein the first curing agent includes at least one of FXR-1020 and FXR-1081, and the second curing agent includes at least one of FXR-1060cs and FXR-1070cs.

7. The epoxy adhesive according to claim 1, characterized in that: The filler is at least one of spherical silica powder and talc powder, and the particle size D50 of the filler is 3-10 μm.

8. The epoxy adhesive according to claim 1, characterized in that: The raw materials also include 0.1-0.5 parts of a curing accelerator, wherein the curing accelerator is at least one of 2-ethyl-4-methylimidazole and 1-cyanoethyl-2-ethyl-4-methylimidazole.

9. A method for preparing the epoxy adhesive as described in any one of claims 1 to 8, characterized in that: Includes the following steps: (1) The epoxy resin, toughening agent, diluent, dispersant, defoamer and coupling agent are mixed to obtain the first mixture; (2) The first mixture is mixed with filler, fumed silica and carbon black to obtain a second mixture; (3) The second mixture is mixed with the curing agent to obtain the epoxy adhesive.

10. The application of the epoxy adhesive as described in any one of claims 1 to 8 in the packaging of PCB components.

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