Elastic glue for connecting flexible circuit and rigid device

Abstract

The invention discloses an elastic adhesive for connecting a flexible circuit and a rigid device, and relates to the technical field of adhesive materials. The elastic glue is composed of a component A and a component B, the component A is prepared from the following components in parts by mass: 30 to 50 parts of bio-based polyurethane, 40 to 60 parts of modified epoxy resin, 10 to 20 parts of filler and 10 to 15 parts of diluent; and the component B is a mixed curing agent. According to the preparation method, acrylpimaric acid is purified, then acrylpimaric acid cyclic carbonate is synthesized, isocyanate is replaced, bio-based polyurethane is prepared through ring-opening addition of the acrylpimaric acid cyclic carbonate and polyamine, and the elasticity of epoxy resin is enhanced; unsaturated conjugated double bonds in the linoleic acid polyether polyol are self-crosslinked with oxygen at room temperature to form a net structure, so that the bonding strength of the epoxy resin is improved; the terminal carboxyl group of the epoxidized terminal carboxyl nitrile rubber and the epoxy group of the epoxy resin are subjected to esterification reaction to generate ester bonds, so that the interaction between the two is enhanced, the toughness is improved, and the mechanical strength is not influenced.

Description

Technical Field

[0001] The invention relates to the technical field of adhesive materials, in particular to an elastic adhesive used for connecting a flexible circuit with a rigid device. Background Art

[0002] In the field of flexible electronic device technology, the connection between flexible circuits and rigid devices is easily damaged due to strain, such as smart clothing, wearable devices and flexible displays. This damage affects product quality and may also cause partial or complete functional failure of the product, limiting the product's service life while increasing maintenance costs and affecting economic benefits.

[0003] Chinese patent CN110305609A discloses a two-component flexible composite epoxy resin adhesive, the main components of which are mixed epoxy resin, catalyst, epoxy soybean oil, curing catalyst, silane coupling agent, reactive diluent, additive and mixed curing agent. This method solves the contradiction between epoxy resin bonding strength and toughness, but the graphene oxide used in the preparation process is modified by isocyanate, which is highly toxic. Commonly used isocyanate monomers, such as toluene diisocyanate and diphenylmethane diisocyanate, have been listed as CMR chemicals, with major risks such as carcinogenicity and teratogenicity.

[0004] Therefore, the present invention proposes an elastic adhesive for connecting a flexible circuit with a rigid device. From the perspective of environmental protection and production safety, a two-component epoxy resin elastic adhesive is prepared using low-toxic or non-toxic raw materials. Summary of the invention

[0005] The purpose of the present invention is to provide an elastic adhesive for connecting a flexible circuit with a rigid device, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solution: an elastic adhesive for connecting a flexible circuit with a rigid device, comprising component A and component B.

[0007] Further, the component A comprises the following components by mass: 30 to 50 parts of bio-based polyurethane, 40 to 60 parts of modified epoxy resin, 10 to 20 parts of filler, and 10 to 15 parts of diluent;

[0008] The B component includes meta-phenylenediamine and polyamide.

[0009] Furthermore, the filler is CaCO3, CAS No. 471-34-1, mesh size: 400, sourced from Guangxi Hezhou Junfei Powder Co., Ltd.;

[0010] The diluent is ethylene glycol diglycidyl ether, CAS No. 26403-72-5, which comes from Jiangsu Runfeng Synthetic Technology Co., Ltd.

[0011] An elastic adhesive for connecting a flexible circuit with a rigid device is prepared by the following process:

[0012] Component A and component B are mixed, stirred evenly, and cured to obtain an elastic adhesive.

[0013] Furthermore, the mass ratio of component A to component B is (2-5):(1-5).

[0014] Furthermore, the curing process conditions are: temperature -20 to 100° C., time 5 to 20 hours.

[0015] Further, component A is prepared by the following process:

[0016] The bio-based polyurethane, the modified epoxy resin, the filler and the diluent are mixed and stirred to obtain the A component.

[0017] Furthermore, the mass ratio of bio-based polyurethane, modified epoxy resin, filler and diluent is (30-50): (40-60): (10-20): (10-15).

[0018] Furthermore, the stirring process conditions are: temperature 35-40° C., rotation speed 250-350 r / min, and time 60-80 min.

[0019] Further, component B is prepared by the following process:

[0020] Mix m-phenylenediamine and polyamide in a mass ratio of 1:(5-10), stir evenly at 50-90° C. to obtain component B.

[0021] Further, m-phenylenediamine: CAS number is 108-45-2, which is derived from Merck reagents;

[0022] Polyamide: CAS number is 63428-83-1, from Merck reagent.

[0023] Further, bio-based polyurethane is prepared by the following process:

[0024] Acrylopimaric acid cyclocarbonate, polyethyleneimine and ethylenediamine are mixed, stirred evenly, vacuumed and cured to obtain bio-based polyurethane.

[0025] Furthermore, the mass ratio of acrylpimaric acid cyclocarbonate, polyethyleneimine and ethylenediamine is 4:(1-1.5):(0.7-1.1).

[0026] Furthermore, the curing process conditions are: temperature 60-80° C., time 18-24 h.

[0027] Further, polyethyleneimine: CAS number is 9002-98-6, which is sourced from Shanghai Yushicheng Chemical Technology Co., Ltd.;

[0028] Ethylenediamine: CAS number is 107-15-3, purity is 99%, and it comes from Nanjing Xinhuayuan Chemical Co., Ltd.

[0029] Further, the propylene pimaric acid cyclic carbonate is prepared by the following process:

[0030] S1: Mix propylene rosin and ethyl acetate, heat to react, add petroleum ether after cooling, crystallize, and filter under reduced pressure to obtain propylene pimaric acid;

[0031] S2: Mix acrylpimaric acid, epichlorohydrin and benzyltriethylammonium chloride, and react under a nitrogen atmosphere with magnetic stirring. Then, add sodium hydroxide and calcium oxide, react for 2 to 3 hours, filter, and remove epichlorohydrin by vacuum distillation to obtain acrylpimaric acid diglycidyl ether;

[0032] S3: Mix propylene pimaric acid diglycidyl ether, tetrabutylammonium iodide and L-ascorbic acid, fill with CO2, pressurize to 0.30-0.35 MPa, heat to react, exhaust CO2 gas after the reaction, and obtain propylene pimaric acid cyclocarbonate.

[0033] Further, the mass ratio of propylene rosin, ethyl acetate and petroleum ether in S1 is 1:(0.3-0.5):(2-2.5);

[0034] The process conditions of the heating reaction in S1 are: temperature 70-80°C, time 1-2h.

[0035] Further, propylene rosin: CAS number is 85026-55-7, from Merck reagent;

[0036] Ethyl acetate: CAS number is 141-78-6, from Jinan Zesheng Chemical Co., Ltd.;

[0037] Petroleum ether: CAS number is 64742-49-0, sourced from Foshan Changxing New Materials Co., Ltd.

[0038] Furthermore, the mass ratio of acrylpimaric acid, epichlorohydrin, benzyltriethylammonium chloride, sodium hydroxide, and calcium oxide in S2 is 1:(3-5):(0.01-0.1):(0.1-0.2):(0.1-0.15);

[0039] The process conditions of magnetic stirring in S2 are: temperature 100-120°C, time 1-2h, speed 30-60r / min;

[0040] The process conditions of vacuum distillation are: temperature: 50-60°C, time 20-30min, vacuum degree: 0.088-0.098MPa.

[0041] Further, epichlorohydrin: CAS number is 106-89-8, purity is 99%, and it comes from Jinan Century Tongda Chemical Co., Ltd.;

[0042] Benzyltriethylammonium chloride: CAS number is 56-37-1, purity is 99%, sourced from Jinan Yuyi Chemical Co., Ltd.

[0043] Sodium hydroxide: CAS number is 1310-73-2, purity is 99%, from Jinan Haowen Chemical Co., Ltd.;

[0044] Calcium oxide: CAS number is 1305-78-8, purity is 99%, and it comes from Zibo Wanpu New Materials Co., Ltd.

[0045] Furthermore, the mass ratio of acrylpimaric acid diglycidyl ether, tetrabutylammonium iodide, and L-ascorbic acid in S3 is 1:(0.03-0.07):(0.01-0.02);

[0046] The process conditions of the temperature-raising reaction are: temperature 70-80°C, time 24-48h.

[0047] Further, tetrabutylammonium iodide: CAS number 311-28-4, from Merck reagent;

[0048] L-Ascorbic acid: CAS number is 50-81-7, from Merck reagent.

[0049] In the above technical scheme, propylene rosin can form a stable and elastic polymer chain during the polymerization process. propylene pimaric acid is purified by propylene rosin, and then propylene pimaric acid cyclocarbonate is synthesized to replace isocyanate and react with polyamines to prepare bio-based polyurethane, which has good elasticity. The acrylic acid group in propylene pimaric acid gives the material good flexibility and adaptability. At the same time, propylene pimaric acid cyclocarbonate is obtained by catalytic conversion of epoxides by CO2, has high environmental protection, is in line with the country's "dual carbon" strategy, and has good development and application prospects.

[0050] Further, the modified epoxy resin is prepared by the following process:

[0051] The epoxy resin, epoxidized carboxyl-terminated nitrile rubber, linolenic acid polyether polyol and 2,4,6-tris(dimethylaminomethyl)phenol are mixed, degassed at 60-65°C, and cured to obtain a modified epoxy resin.

[0052] Furthermore, the mass ratio of epoxy resin, epoxidized carboxyl-terminated nitrile rubber, linolenic acid polyether polyol, and 2,4,6-tris(dimethylaminomethyl)phenol is 1:(0.3-0.5):(0.2-0.4):(0.03-0.05).

[0053] Furthermore, the curing process conditions are: temperature 80-120° C., time 10-18 h.

[0054] Furthermore, the epoxy resin is bisphenol F epoxy resin 862, epoxy equivalent: 168-182, viscosity: 3500-5000, from Hubei Langbowan Biopharmaceutical Co., Ltd.;

[0055] 2,4,6-Tris(dimethylaminomethyl)phenol: CAS number is 90-72-2, purity: 99%, sourced from Hubei Xingyan New Materials Technology Co., Ltd.

[0056] Further, linolenic acid polyether polyol is prepared by the following process:

[0057] Mix hydroquinone diglycidyl ether and linoleic acid, heat to 110-120°C under nitrogen atmosphere, then drop N,N-dimethylbenzylamine, stir to react, test the acid value of the system, and the reaction is completed when the acid value remains basically unchanged to obtain linoleic acid polyether polyol.

[0058] Furthermore, the molar ratio of resorcinol diglycidyl ether, linoleic acid, and N,N-dimethylbenzylamine is 1:(1.8-2):(0.03-0.05).

[0059] Further, resorcinol diglycidyl ether: CAS number 101-90-6, purity 99%, sourced from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.;

[0060] Linolenic acid, mesh size: 80, from Xi'an Tongjiang Biotechnology Co., Ltd.;

[0061] N,N-Dimethylbenzylamine: CAS number is 103-83-3, purity is 99%, and it comes from Shengwanjia New Materials (Shandong) Co., Ltd.

[0062] Further, the epoxidized carboxyl-terminated nitrile rubber is prepared by the following process:

[0063] The carboxyl-terminated nitrile rubber, toluene and formic acid are mixed and kept at a constant temperature of 5-10°C, and then hydrogen peroxide is added and the temperature is increased to react. After the reaction is completed, the nitrile rubber is washed with deionized water and rotary evaporated to obtain the epoxidized carboxyl-terminated nitrile rubber.

[0064] Furthermore, the mass ratio of the carboxyl-terminated nitrile rubber, toluene, formic acid and hydrogen peroxide is 1:(5-10):(0.6-1):(0.6-1).

[0065] Furthermore, the process conditions of the temperature-raising reaction are: temperature 35-40° C., time 0.6-1 h.

[0066] Furthermore, the process conditions of rotary evaporation are: temperature 45-55°C, rotation speed 50-100r / min, and vacuum degree 0.08-0.1MPa.

[0067] Further, carboxyl-terminated nitrile rubber: CAS No. 25265-19-4, viscosity: 10000, sourced from Wuhan Kemik Biopharmaceutical Technology Co., Ltd.;

[0068] Toluene: CAS number is 108-88-3, from Merck reagent;

[0069] Formic acid: CAS number is 64-18-6, purity is 99%, sourced from Jinan Qichen Chemical Co., Ltd.

[0070] Hydrogen peroxide: CAS number is 7722-84-1, from Merck Reagent.

[0071] In the above technical scheme, linoleic acid polyether polyol is synthesized with linoleic acid as raw material. Linoleic acid contains unsaturated conjugated double bonds, which self-crosslink with oxygen at room temperature to form a network structure, thereby improving the bonding strength of the material; the epoxy group in resorcinol diglycidyl ether is introduced into linoleic acid, thereby improving the adhesion, stability and mechanical properties of the polyether polyol; resorcinol diglycidyl ether also contains ether bonds, thereby further improving the flexibility, low temperature resistance and hydrolysis resistance of the polyol. The carboxyl group of the carboxyl-terminated nitrile rubber undergoes an esterification reaction with the epoxy group of the epoxy resin to generate an ester bond, thereby enhancing the interaction between the two, improving the brittleness of the epoxy resin, and further improving its toughness and bonding strength, but the modulus and strength of the matrix decrease, therefore, the carboxyl-terminated nitrile rubber is epoxidized, and the epoxy group is introduced to enhance the reactivity with the curing agent, while improving the compatibility with the epoxy resin, thereby improving the toughness without affecting its mechanical strength. In the mixed curing agent, polyamide has good toughness and polarity, which enhances the bonding strength of the epoxy resin, improves the brittleness of the epoxy resin, and increases its toughness. Metaphenylenediamine has good thermal stability, corrosion resistance, and moisture and gas barrier properties, which can improve the heat resistance of the elastic glue and extend the service life of electronic components.

[0072] Compared with the prior art, the present invention has the following beneficial effects:

[0073] 1. Acrylic rosin can form stable and elastic polymer chains during the polymerization process. Acrylic pimaric acid can be purified from acrylic rosin and then acrylic pimaric acid cyclocarbonate can be synthesized by purifying acrylic pimaric acid from acrylic rosin. It can replace isocyanate and react with polyamines to prepare bio-based polyurethane, which has good elasticity. At the same time, the acrylic acid group gives bio-based polyurethane good flexibility and adaptability. Acrylic pimaric acid cyclocarbonate is obtained by catalytic conversion of epoxides using CO2, has high environmental protection, is in line with the country's "dual carbon" strategy, and has good development and application prospects.

[0074] 2. Linoleic acid polyether polyol was synthesized from linoleic acid. Linoleic acid contains unsaturated conjugated double bonds, which can self-crosslink with oxygen at room temperature to form a network structure, thereby improving the bonding strength of the material. The epoxy group in resorcinol diglycidyl ether was introduced into linoleic acid, thereby improving the adhesion, stability and mechanical properties of the polyether polyol. Resorcinol diglycidyl ether also contains ether bonds, thereby further improving the flexibility, low temperature resistance and hydrolysis resistance of the polyol. The carboxyl group of the carboxyl-terminated nitrile rubber reacts with the epoxy group of the epoxy resin to form an ester bond, thereby enhancing the interaction between the two, improving the brittleness of the epoxy resin, and further improving its toughness and bonding strength. However, the modulus and strength of the matrix are reduced. Therefore, the carboxyl-terminated nitrile rubber is epoxidized to introduce epoxy groups, thereby enhancing the reactivity with the curing agent and improving the compatibility with the epoxy resin, thereby improving the toughness without affecting its mechanical strength. In the mixed curing agent, polyamide has good toughness and polarity, which enhances the bonding strength of the epoxy resin, improves the brittleness of the epoxy resin, and increases its toughness. Metaphenylenediamine has good thermal stability, corrosion resistance, and moisture and gas barrier properties, which can improve the heat resistance of the elastic glue and extend the service life of electronic components. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 This is a schematic diagram of the structure of an elastic adhesive for connecting a flexible circuit with a rigid device according to the present invention;

[0076] In the figure, 1-rigid device, 2-elastic glue, 3-flexible circuit.

[0077] Figure 2 This is a product picture of the elastic glue obtained in Example 3 of the present invention. DETAILED DESCRIPTION

[0078] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0079] In the following specific implementations,

[0080] The filler is CaCO3, CAS No. 471-34-1, mesh size: 400, from Guangxi Hezhou Junfei Powder Co., Ltd.

[0081] The diluent is ethylene glycol diglycidyl ether, CAS No. 26403-72-5, from Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0082] Metaphenylenediamine: CAS number is 108-45-2, from Merck reagent;

[0083] Polyamide: CAS number is 63428-83-1, from Merck reagent;

[0084] Polyethyleneimine: CAS number is 9002-98-6, from Shanghai Yushicheng Chemical Technology Co., Ltd.;

[0085] Ethylenediamine: CAS number is 107-15-3, purity is 99%, sourced from Nanjing Xinhuayuan Chemical Co., Ltd.;

[0086] Propylene rosin: CAS number is 85026-55-7, from Merck reagent;

[0087] Ethyl acetate: CAS number is 141-78-6, from Jinan Zesheng Chemical Co., Ltd.;

[0088] Petroleum ether: CAS number is 64742-49-0, from Foshan Changxing New Materials Co., Ltd.

[0089] Epichlorohydrin: CAS number is 106-89-8, purity is 99%, sourced from Jinan Century Tongda Chemical Co., Ltd.

[0090] Benzyltriethylammonium chloride: CAS number is 56-37-1, purity is 99%, sourced from Jinan Yuyi Chemical Co., Ltd.

[0091] Sodium hydroxide: CAS number is 1310-73-2, purity is 99%, from Jinan Haowen Chemical Co., Ltd.;

[0092] Calcium oxide: CAS number is 1305-78-8, purity is 99%, sourced from Zibo Wanpu New Materials Co., Ltd.

[0093] Tetrabutylammonium iodide: CAS number is 311-28-4, from Merck reagent;

[0094] L-ascorbic acid: CAS number is 50-81-7, from Merck reagent;

[0095] The epoxy resin is bisphenol F epoxy resin 862, epoxy equivalent: 168-182, viscosity: 3500-5000, from Hubei Langbowan Biopharmaceutical Co., Ltd.;

[0096] 2,4,6-Tris(dimethylaminomethyl)phenol: CAS number is 90-72-2, purity: 99%, sourced from Hubei Xingyan New Materials Technology Co., Ltd.

[0097] Resorcinol diglycidyl ether: CAS number is 101-90-6, purity is 99%, from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.

[0098] Linolenic acid, mesh size: 80, from Xi'an Tongjiang Biotechnology Co., Ltd.;

[0099] N,N-dimethylbenzylamine: CAS number is 103-83-3, purity is 99%, from Shengwanjia New Materials (Shandong) Co., Ltd.

[0100] Carboxyl-terminated nitrile rubber: CAS number is 25265-19-4, viscosity: 10000, from Wuhan Kemik Biopharmaceutical Technology Co., Ltd.;

[0101] Toluene: CAS number is 108-88-3, from Merck reagent;

[0102] Formic acid: CAS number is 64-18-6, purity is 99%, sourced from Jinan Qichen Chemical Co., Ltd.

[0103] Hydrogen peroxide: CAS number is 7722-84-1, from Merck reagent;

[0104] Polyurethane: CAS number is 51852-81-4, purity is 99%, and it comes from Hubei Chengfeng Chemical Co., Ltd.

[0105] Embodiment 1: A process for preparing an elastic adhesive for connecting a flexible circuit to a rigid device, comprising the following steps:

[0106] (1) Preparation of component A:

[0107] S1: Mix propylene rosin and ethyl acetate, heat to 70℃ and react for 1h, add petroleum ether after cooling, crystallize, and filter under reduced pressure to obtain propylene pimaric acid; the mass ratio of propylene rosin, ethyl acetate and petroleum ether is 1:0.3:2; S2: Mix propylene pimaric acid, epichlorohydrin and benzyltriethylammonium chloride, react under nitrogen atmosphere, and then add sodium hydroxide and calcium oxide, react for 2h, filter, and remove epichlorohydrin by vacuum distillation to obtain propylene pimaric acid diglycidyl ether; the mass ratio of propylene pimaric acid, epichlorohydrin, benzyltriethylammonium chloride, sodium hydroxide and calcium oxide is 1:3:0.01:0.1:0.1; the process conditions of magnetic stirring are: temperature 100 ℃, time 1h, speed 30r / min; the process conditions of vacuum distillation are: temperature: 50℃, time 20min, vacuum degree: 0.088MPa; S3: Mix propylene pimaric acid diglycidyl ether, tetrabutylammonium iodide, and L-ascorbic acid in a mass ratio of 1:0.03:0.01, fill with CO2, pressurize to 0.30MPa, heat to 70℃ and react for 24h. After the reaction, exhaust the CO2 gas to obtain propylene pimaric acid cyclocarbonate; Mix propylene pimaric acid cyclocarbonate, polyethyleneimine, and ethylenediamine in a mass ratio of 4:1:0.7, stir evenly, evacuate, and cure to obtain bio-based polyurethane; the curing process conditions are: temperature 60℃, time 18h;

[0108] Mix resorcinol diglycidyl ether and linoleic acid, heat to 110°C under nitrogen atmosphere, then drop N,N-dimethylbenzylamine, stir to react, test the acid value of the system, and the reaction is completed when the acid value remains basically unchanged to obtain linoleic acid polyether polyol; the molar ratio of resorcinol diglycidyl ether, linoleic acid, and N,N-dimethylbenzylamine is 1:1.8:0.03; mix carboxyl-terminated nitrile rubber, toluene, and formic acid and keep the temperature at 5°C, then add hydrogen peroxide, heat to 35°C and react for 0.6h, wash with deionized water after the reaction, and rotary evaporate to obtain Epoxidized carboxyl-terminated nitrile rubber; the mass ratio of carboxyl-terminated nitrile rubber, toluene, formic acid, and hydrogen peroxide is 1:5:0.6:0.6; the process conditions of rotary evaporation are: temperature 45°C, rotation speed 50r / min, and vacuum degree 0.08MPa; epoxy resin, epoxidized carboxyl-terminated nitrile rubber, linolenic acid polyether polyol, and 2,4,6-tris(dimethylaminomethyl)phenol are mixed in a mass ratio of 1:0.3:0.2:0.03, degassed at 60°C, and cured to obtain modified epoxy resin; the process conditions of curing are: temperature 80°C, time 10h;

[0109] The bio-based polyurethane, modified epoxy resin, filler and diluent were mixed in a mass ratio of 30:40:10:10 and stirred to obtain component A; the stirring process conditions were: temperature 35°C, rotation speed 250r / min, and time 60min;

[0110] (2) Preparation of component B:

[0111] Mix m-phenylenediamine and polyamide in a mass ratio of 1:5, and stir evenly at 50°C to obtain component B;

[0112] (3) Preparation of elastic glue:

[0113] Component A and component B are mixed in a mass ratio of 2:1, stirred evenly, and cured to obtain an elastic adhesive; the curing process conditions are: temperature -20°C, time 5h.

[0114] Embodiment 2: A process for preparing an elastic adhesive for connecting a flexible circuit to a rigid device, comprising the following steps:

[0115] (1) Preparation of component A:

[0116] Propylene rosin and ethyl acetate were mixed, heated to 75°C for 1.5h, and petroleum ether was added after cooling to crystallize and filter under reduced pressure to obtain propylene pimaric acid; the mass ratio of propylene rosin, ethyl acetate and petroleum ether was 1:0.4:2.3; propylene pimaric acid, epichlorohydrin and benzyltriethylammonium chloride were mixed, and reacted with magnetic stirring under the protection of nitrogen atmosphere, and then sodium hydroxide and calcium oxide were added, reacted for 2.5h, filtered, and epichlorohydrin was removed by vacuum distillation to obtain propylene pimaric acid diglycidyl ether; the mass ratio of propylene pimaric acid, epichlorohydrin, benzyltriethylammonium chloride, sodium hydroxide and calcium oxide was 1:4:0.06:0.15:0.13; the process conditions of magnetic stirring were: temperature 110 ℃, time 1.5h, speed 45r / min; the process conditions of vacuum distillation are: temperature: 55℃, time 25min, vacuum degree: 0.093MPa; propylene pimaric acid diglycidyl ether, tetrabutylammonium iodide, and L-ascorbic acid are mixed in a mass ratio of 1:0.05:0.015, filled with CO2, pressurized to 0.33MPa, heated to 75℃ for reaction for 36h, and vented CO2 gas after the reaction to obtain propylene pimaric acid cyclocarbonate; propylene pimaric acid cyclocarbonate, polyethyleneimine, and ethylenediamine are mixed in a mass ratio of 4:1.3:0.9, stirred evenly, vacuumed, and cured to obtain bio-based polyurethane; the curing process conditions are: temperature 70℃, time 20h;

[0117] Mix resorcinol diglycidyl ether and linoleic acid, heat to 115°C under nitrogen atmosphere, then drop N,N-dimethylbenzylamine, stir to react, test the acid value of the system, and the reaction is completed when the acid value remains basically unchanged to obtain linoleic acid polyether polyol; the molar ratio of resorcinol diglycidyl ether, linoleic acid, and N,N-dimethylbenzylamine is 1:1.9:0.04; mix carboxyl-terminated nitrile rubber, toluene, and formic acid and keep the temperature at 7°C, then add hydrogen peroxide, heat to 37°C and react for 0.8h, wash with deionized water after the reaction, and rotary evaporate to obtain Epoxidized carboxyl-terminated nitrile rubber; the mass ratio of carboxyl-terminated nitrile rubber, toluene, formic acid, and hydrogen peroxide is 1:7:0.8:0.8; the process conditions of rotary evaporation are: temperature 50°C, rotation speed 75r / min, and vacuum degree 0.09MPa; epoxy resin, epoxidized carboxyl-terminated nitrile rubber, linolenic acid polyether polyol, and 2,4,6-tris(dimethylaminomethyl)phenol are mixed in a mass ratio of 1:0.4:0.3:0.04, degassed at 63°C, and cured to obtain modified epoxy resin; the process conditions of curing are: temperature 100°C, time 14h;

[0118] The bio-based polyurethane, modified epoxy resin, filler and diluent were mixed in a mass ratio of 40:50:15:13 and stirred to obtain component A; the stirring process conditions were: temperature 37°C, rotation speed 300r / min, and time 70min;

[0119] (2) Preparation of component B:

[0120] Mix m-phenylenediamine and polyamide in a mass ratio of 1:7, and stir evenly at 70°C to obtain component B;

[0121] (3) Preparation of elastic glue:

[0122] Component A and component B are mixed in a mass ratio of 3:3, stirred evenly, and cured to obtain an elastic adhesive; the curing process conditions are: temperature 40°C, time 12h.

[0123] Embodiment 3: A process for preparing an elastic adhesive for connecting a flexible circuit to a rigid device, comprising the following steps:

[0124] (1) Preparation of component A:

[0125] Propylene rosin and ethyl acetate were mixed, heated to 80°C for 2 hours, and petroleum ether was added after cooling to crystallize and filter under reduced pressure to obtain propylene pimaric acid; the mass ratio of propylene rosin, ethyl acetate and petroleum ether was 1:0.5:2.5; propylene pimaric acid, epichlorohydrin and benzyltriethylammonium chloride were mixed, and reacted with magnetic stirring under the protection of nitrogen atmosphere, and then sodium hydroxide and calcium oxide were added, reacted for 3 hours, filtered, and epichlorohydrin was removed by vacuum distillation to obtain propylene pimaric acid diglycidyl ether; the mass ratio of propylene pimaric acid, epichlorohydrin, benzyltriethylammonium chloride, sodium hydroxide and calcium oxide was 1:5:0.1:0.2:0.15; the process conditions of magnetic stirring were: temperature 120°C, time The process conditions of vacuum distillation are as follows: temperature: 60℃, time: 30min, vacuum degree: 0.098MPa; propylene pimaric acid diglycidyl ether, tetrabutylammonium iodide and L-ascorbic acid are mixed in a mass ratio of 1:0.07:0.02, filled with CO2, pressurized to 0.35MPa, heated to 80℃ and reacted for 48h. After the reaction, the CO2 gas is vented to obtain propylene pimaric acid cyclocarbonate; propylene pimaric acid cyclocarbonate, polyethyleneimine and ethylenediamine are mixed in a mass ratio of 4:1.5:1.1, stirred evenly, vacuumized and cured to obtain bio-based polyurethane; the curing process conditions are as follows: temperature 80℃, time 18-24h;

[0126] Mix resorcinol diglycidyl ether and linoleic acid, heat to 120°C under nitrogen atmosphere, then drop N,N-dimethylbenzylamine, stir to react, test the acid value of the system, and the reaction is completed when the acid value remains basically unchanged to obtain linoleic acid polyether polyol; the molar ratio of resorcinol diglycidyl ether, linoleic acid, and N,N-dimethylbenzylamine is 1:2:0.05; mix carboxyl-terminated nitrile rubber, toluene, and formic acid and keep the temperature at 10°C, then add hydrogen peroxide, heat to 40°C and react for 1h, wash with deionized water after the reaction, and rotary evaporate to obtain Epoxidized carboxyl-terminated nitrile rubber; the mass ratio of carboxyl-terminated nitrile rubber, toluene, formic acid, and hydrogen peroxide is 1:10:1:1; the process conditions of rotary evaporation are: temperature 55°C, rotation speed 100r / min, and vacuum degree 0.1MPa; epoxy resin, epoxidized carboxyl-terminated nitrile rubber, linolenic acid polyether polyol, and 2,4,6-tris(dimethylaminomethyl)phenol are mixed in a mass ratio of 1:0.5:0.4:0.05, degassed at 65°C, and cured to obtain a modified epoxy resin; the process conditions of curing are: temperature 120°C, time 18h;

[0127] The bio-based polyurethane, modified epoxy resin, filler and diluent were mixed in a mass ratio of 50:60:20:15 and stirred to obtain component A; the stirring process conditions were: temperature 40°C, rotation speed 350r / min, and time 80min;

[0128] (2) Preparation of component B:

[0129] Mix m-phenylenediamine and polyamide in a mass ratio of 1:10, and stir evenly at 90°C to obtain component B;

[0130] (3) Preparation of elastic glue:

[0131] Component A and component B are mixed in a mass ratio of 5:5, stirred evenly, and cured to obtain an elastic adhesive; the curing process conditions are: temperature 100°C, time 20 hours.

[0132] Comparative Example 1: Using Example 1 as a comparison, the bio-based polyurethane was replaced with commercially available polyurethane, and the other steps remained unchanged.

[0133] Comparative Example 2: Using Example 1 as a comparison, the epoxy resin was not modified and the other steps remained unchanged.

[0134] Comparative Example 3: Compared with Example 1, no curing agent is used, and the elastic glue is formed by relying on the curing properties of the epoxy resin itself, and the other steps remain unchanged.

[0135] Experiment: The elastic glue obtained in Examples 1 to 3 and Comparative Examples 1 to 3 was prepared into samples, and the properties thereof were tested respectively:

[0136] Mechanical properties test: The tensile strength and elongation at break of the elastic rubber samples were tested using a UTM6502 tensile testing machine at 200°C, 25°C, and -60°C, with reference to GB / T 2570-1995, and the tensile rate was set to 2 mm / min;

[0137] Bending test: According to DIN EN ISO, the bending test was carried out at 200℃, 25℃, and -60℃. The specimen was a straight bar with a cross section of 1.5cm. 2 ×0.4cm 2 , test speed 2mm / min;

[0138] Viscosity test: Use NDJ-79 rotary viscometer to test the viscosity of elastic rubber samples at 200℃, 25℃, and -60℃;

[0139] Stress relaxation test: The elastic rubber samples were subjected to stress relaxation test at 200°C, 25°C, and -60°C using a TA Instruments Q800 dynamic mechanical analyzer. The sample size was 25 mm × 5 mm × 1.5 mm. A constant strain of 1% was applied to the sample.

[0140]

[0141] Table 1 Test results of various properties of elastic rubber samples at 200℃

[0142]

[0143] Table 2 Test results of various properties of elastic rubber samples at 25℃

[0144]

[0145] Table 3 Test results of various properties of elastic rubber samples at -60℃

[0146] According to the data in the above table, we can clearly draw the following conclusions:

[0147] The elastic glue obtained in Examples 1 to 3 is compared with the elastic glue obtained in Comparative Examples 1 to 3. The test results show that:

[0148] Compared with comparative examples 1 to 3, the elastic adhesives obtained in examples 1 to 3 have better tensile strength, elongation at break, bending strength, bonding strength and elasticity.

[0149] Compared with Example 1, Comparative Example 1 replaces bio-based polyurethane with commercially available polyurethane, and its stress relaxation time increases significantly, and the elasticity of the elastic glue decreases; Comparative Example 2 does not use linolenic acid polyether polyol and epoxidized carboxyl-terminated nitrile rubber grafted epoxy resin, and the tensile strength, bonding strength, elongation at break and flexural strength of the elastic glue obtained are significantly reduced; Comparative Example 3 does not use a curing agent, and the bonding strength of the elastic glue obtained is greatly reduced. It can be seen that the preparation process of the elastic glue and the setting of the components used in the present application can promote the comprehensive improvement of its tensile strength, flexural strength, bonding strength, elongation at break and stress relaxation time.

[0150] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. An elastic adhesive for connecting a flexible circuit with a rigid device, characterized in that: It consists of component A and component B, wherein component A includes the following components by weight: 30 to 50 parts of bio-based polyurethane, 40 to 60 parts of modified epoxy resin, 10 to 20 parts of filler, and 10 to 15 parts of diluent; Component B is a mixed curing agent.

2. The elastic adhesive for connecting a flexible circuit and a rigid device according to claim 1, characterized in that: The bio-based polyurethane is prepared by mixing propylene pimaric acid cyclocarbonate with polyethyleneimine and ethylenediamine.

3. The elastic adhesive for connecting a flexible circuit and a rigid device according to claim 1, characterized in that: The modified epoxy resin comprises epoxy resin, epoxidized carboxyl-terminated nitrile rubber and linolenic acid polyether polyol.

4. A method for preparing an elastic adhesive for connecting a flexible circuit with a rigid device, characterized in that: Including the following processes: Bio-based polyurethane, modified epoxy resin, filler and diluent are mixed as component A, meta-phenylenediamine and polyamide are mixed as component B, components A and B are mixed, stirred evenly, and cured to obtain elastic glue.

5. The method for preparing an elastic adhesive for connecting a flexible circuit and a rigid device according to claim 4, characterized in that: The curing process conditions are: temperature -20 to 100°C, time 5 to 20 hours.

6. The method for preparing an elastic adhesive for connecting a flexible circuit and a rigid device according to claim 4, characterized in that: Component A is prepared by the following process: The bio-based polyurethane, the modified epoxy resin, the filler and the diluent are mixed and stirred to obtain the A component.

7. The method for preparing an elastic adhesive for connecting a flexible circuit and a rigid device according to claim 6, characterized in that: Bio-based polyurethane is produced by the following process: The method comprises mixing propylene pimaric acid cyclocarbonate, polyethyleneimine and ethylenediamine, stirring evenly, vacuumizing and curing to obtain bio-based polyurethane.

8. The method for preparing an elastic adhesive for connecting a flexible circuit and a rigid device according to claim 6, characterized in that: Modified epoxy resin is prepared by the following process: The epoxy resin, epoxidized carboxyl-terminated nitrile rubber, linolenic acid polyether polyol and 2,4,6-tris(dimethylaminomethyl)phenol are mixed, degassed at 60-65°C, and cured to obtain a modified epoxy resin.

9. The method for preparing an elastic adhesive for connecting a flexible circuit and a rigid device according to claim 6, characterized in that: The mass ratio of bio-based polyurethane, modified epoxy resin, filler and diluent is (30-50): (40-60): (10-20): (10-15).

10. The method for preparing an elastic adhesive for connecting a flexible circuit and a rigid device according to claim 8, characterized in that: The mass ratio of epoxy resin, epoxidized carboxyl-terminated nitrile rubber, linolenic acid polyether polyol and 2,4,6-tris(dimethylaminomethyl)phenol is 1:(0.3-0.5):(0.2-0.4):(0.03-0.05).

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