Acrylate conductive composite pressure-sensitive adhesive and preparation method thereof

Abstract

The invention discloses an acrylate conductive composite pressure-sensitive adhesive and a preparation method thereof. The acrylate conductive composite pressure-sensitive adhesive comprises a raw material A and a raw material B, wherein the raw material A comprises 5-15 parts of acrylate polymer; 0.10 to 1.00 parts of epoxy resin; 1.0 to 10.0 parts of aniline; 0.1 to 1.0 part of an initiator; 1-5 parts of conductive particles; and 0.010 to 0.100 part of an amine curing agent. The acrylate conductive composite pressure-sensitive adhesive disclosed by the invention has excellent conductivity and capacitance sensing performance, and shows excellent capacitance stability and relatively high sensitivity in a pressure cycle test; on the basis of containing the conductive filler, the pressure-sensitive adhesive still has better hardness, adhesion strength and tensile strength, and the conductive filler is well dispersed and combined in a pressure-sensitive adhesive system.

Description

Technical Field

[0001] The invention relates to the field of adhesives, and in particular to an acrylate conductive composite pressure-sensitive adhesive and a preparation method thereof. Background Art

[0002] With the rapid development of the electronic and electrical industry, conductive pressure-sensitive adhesives have attracted much attention due to their excellent electrical properties and adhesion functions. By filling conductive fillers in pressure-sensitive adhesives, a relatively continuous conductive network can be formed in the pressure-sensitive adhesive matrix to improve its conductive properties. However, since conductive fillers are generally micron or nanometer-level conductive particles, they have a high specific surface area and are easy to agglomerate, affecting the overall electrical properties of the material. In addition, a high content of conductive fillers can also easily lead to a decrease in mechanical properties.

[0003] Therefore, providing a technical means to ensure that the conductive properties and mechanical properties of acrylic pressure-sensitive adhesives meet the requirements of use is a technical problem that needs to be solved urgently. Summary of the invention

[0004] To achieve the above object, the present invention provides an acrylate conductive composite pressure-sensitive adhesive and a preparation method thereof.

[0005] The present invention provides an acrylate conductive composite pressure-sensitive adhesive, wherein the raw material A comprises:

[0006] 5-15 parts of acrylic acid ester polymer;

[0007] 0.10-1.00 parts of epoxy resin;

[0008] 1.0-10.0 parts of aniline;

[0009] 0.1-1.0 parts of initiator;

[0010] 1-5 parts of conductive particles;

[0011] 0.010-0.100 parts of amine curing agent;

[0012] in:

[0013] The acrylic ester polymer is prepared by the following method: raw material B is mixed and polymerized to obtain;

[0014] The raw material B comprises:

[0015] 40-60 parts of isooctyl acrylate;

[0016] 25-50 parts of butyl acrylate;

[0017] 10-20 parts of glycidyl methacrylate;

[0018] 1-10 parts of acrylic acid;

[0019] 1 - 10 parts of 2 - hydroxyethyl methacrylate;

[0020] 0.1 - 1.0 part of dodecyl mercaptan;

[0021] 0.1 - 5.0 parts of initiator.

[0022] In a preferred embodiment of the present invention, in the raw material B, the number of parts of isooctyl acrylate is 50 parts.

[0023] In a preferred embodiment of the present invention, in the raw material B, the number of parts of butyl acrylate is 25 - 50 parts, such as 25 parts or 50 parts.

[0024] In a preferred embodiment of the present invention, in the raw material B, the mass ratio of isooctyl acrylate to butyl acrylate is (1 - 2):1.

[0025] In a preferred embodiment of the present invention, in the raw material B, the number of parts of glycidyl methacrylate is 10 - 15 parts, such as 12.5 parts or 15 parts.

[0026] In a preferred embodiment of the present invention, in the raw material B, the number of parts of acrylic acid is 1 - 5 parts, such as 3.5 parts or 5 parts.

[0027] In a preferred embodiment of the present invention, in the raw material B, the number of parts of 2 - hydroxyethyl methacrylate is 1 - 5 parts, such as 3.5 parts.

[0028] In a preferred embodiment of the present invention, in the raw material B, the number of parts of dodecyl mercaptan is 0.1 - 0.5 part, such as 0.3 part.

[0029] In a preferred embodiment of the present invention, in the raw material B, the initiator is benzoyl peroxide.

[0030] In a preferred embodiment of the present invention, in the raw material B, the number of parts of the initiator is 0.1 - 3 parts, such as 1 part.

[0031] In the present invention, the raw material B may further include a solvent.

[0032] In a preferred embodiment of the present invention, the number of parts of the solvent is 100 parts.

[0033] In a preferred embodiment of the present invention, the solvent is ethyl acetate.

[0034] In a preferred embodiment of the present invention, the method for preparing the acrylate polymer comprises the following steps:

[0035] S1, mixing the raw material B in reaction vessel 1 to obtain a mixed material A;

[0036] S2. Slowly drop 20 - 40% of the weight parts of the mixture A into the reaction vessel 2 over a dropping time of 0.5 - 4 h, and then keep the temperature at 70 - 80 °C for heat preservation reaction for 0.2 - 0.4 h to obtain mixture B;

[0037] S3. Add the remaining mixture A to mixture B, heat to 70 - 80 °C, and react for 1 - 5 h to obtain the acrylate polymer.

[0038] In a preferred embodiment of the present invention, in the raw material A, the parts of the acrylate polymer are 10 parts.

[0039] In a preferred embodiment of the present invention, in the raw material A, the parts of the epoxy resin are 0.25 part, 0.50 part, 0.75 part or 1.00 part.

[0040] In a preferred embodiment of the present invention, in the raw material A, the average molecular weight of the epoxy resin is 350 - 400, such as 375.86; the epoxy equivalent is 175 - 200 g / eq, such as the epoxy equivalent is 184 - 194 g / eq.

[0041] In a preferred embodiment of the present invention, in the raw material A, the epoxy resin is E51 glycidyl ether epoxy resin purchased from Baling Petrochemical.

[0042] In a preferred embodiment of the present invention, in the raw material A, the parts of aniline are 2.5 parts, 5.0 parts, 7.5 parts or 10.0 parts.

[0043] In a preferred embodiment of the present invention, in the raw material A, the parts of the initiator are 0.5 part.

[0044] In a preferred embodiment of the present invention, in the raw material A, the type of the initiator is ammonium persulfate.

[0045] In a preferred embodiment of the present invention, in the raw material A, the parts of the conductive particles are 3 parts.

[0046] In a preferred embodiment of the present invention, in the raw material A, the type of the conductive particles is nano - nickel.

[0047] In a preferred embodiment of the present invention, in the raw material A, the parts of the amine curing agent are 0.025 part, 0.050 part, 0.075 part or 0.100 part.

[0048] The present invention also provides a preparation method of the acrylate conductive composite pressure - sensitive adhesive, comprising the following steps:

[0049] (1) Mix the acrylate polymer, the epoxy resin, and the aniline to obtain Mixture 1; dissolve the initiator APS in a solvent to obtain Mixture 2; mix and react Mixture 2 and Mixture 1 to obtain Mixture 3;

[0050] (2) Mix Mixture 3, the conductive particles, and the amine curing agent to obtain Mixture 4, and cure Mixture 4 to obtain the acrylate conductive composite pressure-sensitive adhesive.

[0051] Among them, Mixture 2 can be an H2SO4 solution of APS.

[0052] Among them, preferably, slowly pour Mixture 2 into Mixture 1.

[0053] Among them, preferably, the reaction in step (1) is carried out under ice bath conditions.

[0054] Among them, preferably, the reaction time in step (1) is 30 min.

[0055] Among them, preferably, the curing condition in step (1) is room temperature curing for 24 h.

[0056] The reagents and raw materials used in the present invention are all commercially available.

[0057] The positive and progressive effects of the present invention are as follows:

[0058] The acrylate conductive composite pressure-sensitive adhesive in the present invention has excellent conductivity, capacitance sensing performance, and exhibits excellent capacitance stability and high sensitivity in the pressure cycling test; on the basis of containing conductive fillers, its hardness, adhesion strength, and tensile strength are still good. It can be seen that the conductive fillers are well dispersed and combined in the pressure-sensitive adhesive system. Specific Embodiments

[0059] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0060] In the following examples and comparative examples, the full names and English abbreviations of each raw material are as follows:

[0061] 2-Ethylhexyl acrylate, 2-EHA, with a glass transition temperature Tg of -70 °C;

[0062] Butyl acrylate, BA, with a glass transition temperature Tg of -55 °C;

[0063] Glycidyl methacrylate, GMA, with a glass transition temperature Tg of 40 °C;

[0064] Acrylic acid, AA, with a glass transition temperature Tg of 106 °C;

[0065] 2-Hydroxyethyl methacrylate, HEMA, with a glass transition temperature Tg of 56 °C;

[0066] Dodecyl mercaptan, DDM;

[0067] Benzoyl peroxide, BPO;

[0068] Ethyl acetate, EA;

[0069] Epoxy resin: E51 glycidyl ether epoxy resin purchased from Baling Petrochemical, model CYD - 128; its average molecular weight is 375.86, and the epoxy equivalent is 184 - 194 g / eq;

[0070] Terpene resin: purchased from Guangdong Kemo Forest Chemical Co., Ltd., model KT10;

[0071] Butadiene rubber: purchased from Shenzhen Masni Elastomer Co., Ltd., model LBR - 10K;

[0072] Amine curing agent: 593 type epoxy resin amine curing agent;

[0073] Nano nickel: purchased from Shanghai Naiou Nano Technology Co., Ltd., product number NO - M - 007 - 2.

[0074] Examples 1 - 4

[0075] For the acrylate polymers in Examples 1 - 4, calculated by weight parts, the formula is shown in Table 1 below.

[0076] Table 1

[0077]

[0078]

[0079] According to the formula shown in Table 1, the preparation method of the acrylate polymer is as follows:

[0080] S1: Install a stirrer and a reflux condenser on a 250 mL three - necked flask, turn on the water bath, heat up, and introduce nitrogen.

[0081] S2: The monomers, initiators and solvents shown in Table 1 are mixed to obtain a blend. When the temperature reaches the set temperature shown in Table 1, 1 / 3 of the blend is added to a three-necked flask as a primer. The mixture is stirred at an appropriate rate (about 300 r / min) and reacted for 1 hour. After that, a constant pressure dropping funnel is placed to start dropping the remaining 2 / 3 of the blend. The dropping is completed in about 2 hours. After the dropping is completed, the reaction is kept warm for 4 hours to obtain an acrylate polymer.

[0082] Embodiment 5-8

[0083] The acrylic conductive composite pressure-sensitive adhesive in Examples 5-8 has a formula as shown in Table 2 below, calculated by weight.

[0084] Table 2

[0085]

[0086]

[0087] The preparation method of the acrylate conductive composite pressure-sensitive adhesive is as follows:

[0088] (1) Resin 1, resin 2 and aniline were mixed to obtain mixture 1; initiator APS was dissolved in a beaker containing 10 mL of 1 mol / L H2SO4 and ultrasonicated for 15 min to obtain mixture 2. In an ice bath, the solution containing APS was slowly poured into mixture 1 and reacted for 30 min to obtain mixture 3.

[0089] (2) Mix the mixture 3, the conductive powder and the curing agent, and use mechanical stirring until the mixture 4 is uniform, and the mixture 4 is poured into a molding mold. After 24 hours at room temperature, an acrylic conductive composite pressure-sensitive adhesive is obtained.

[0090] Comparative Example 1

[0091] Except that the E51 epoxy resin is replaced by terpene resin, other conditions are the same as those in Example 4.

[0092] Comparative Example 2

[0093] Except that the E51 epoxy resin is replaced by butadiene rubber, other conditions are the same as those in Example 4.

[0094] Comparative Example 3

[0095] Except that E51 epoxy resin and curing agent were not added, other conditions were the same as those in Example 4.

[0096] Effect Example

[0097] (1) Conductivity test: Use a digital multimeter with a two-probe method to test more than 5 samples and take the average value. The test results are shown in Table 3.

[0098] (2) Pressure capacitance sensor test: The test was performed using an LCR tester (LCR8220, Suzhou Saimier Electronic Technology Co., Ltd.). The test sample size was 2.0 cm × 3.0 cm, and weights of 100, 200, 400, and 800 g were used to test the capacitance change of the test sample under different pressures. Five or more samples were tested and the average value was taken. The test results are shown in Table 3.

[0099] (3) Material hardness test: The material was tested using a Shore hardness tester (Shore hardness tester, type A, Shanghai Gaozhi Precision Instrument Co., Ltd.), with a sample size of 2.0 cm × 3.0 cm. More than 5 samples were tested and the average value was taken. The test results are shown in Table 4.

[0100] (4) Adhesion performance test: Adhesion performance was tested using a universal testing machine (universal testing machine, CMT6104, Shenzhen Xinsansi Metrology Technology Co., Ltd.) according to the method of GB / T 33334-2016. More than 5 specimens were stretched and the average value of the maximum force was taken. Formula (1) was used for calculation:

[0101] τ=(F / s)·10 -3 (1)

[0102] Where: τ: adhesion strength of the sample, kPa; F: maximum tensile shear force of the sample, N; s: adhesion area of ​​the sample, m 2 The test results are shown in Table 4.

[0103] (5) Tensile property test: The test was conducted using a universal testing machine (universal testing machine, CMT6104, Shenzhen Xinsansi Metrology Technology Co., Ltd.). The tensile strength test specimen size was 2.0 cm × 3.0 cm, and the test speed was 20 mm / s. More than 5 samples were tested, and the tensile strength was taken as the average value. The test results are shown in Table 4.

[0104] Table 3

[0105]

[0106]

[0107] Table 4

[0108] Number Hardness / HA Adhesion strength / kPa Tensile strength / kPa Example 5 55 55 158 Example 6 58 58 165 Example 7 60 60 170 Example 8 65 64 178 Comparative Example 1 50 54 155 Comparative Example 2 49 53 153 Comparative Example 3 45 50 150

[0109] According to Table 3 and Table 4, we can know that:

[0110] (1) Compared with Comparative Example 3, the acrylate conductive composite pressure-sensitive adhesives in Examples 1-4 have excellent electrical conductivity and capacitance sensing performance, and exhibit excellent capacitance stability and high sensitivity in the pressure cycle test; on the basis of containing conductive fillers, their hardness, adhesion strength, and tensile strength are still relatively good. It can be seen that the conductive fillers are well dispersed and combined in the pressure-sensitive adhesive system.

[0111] (2) Compared with Comparative Example 1 and Comparative Example 2, the acrylate conductive composite pressure-sensitive adhesives in Examples 1-4 have more excellent performance. The reason may be that the hydrogen bonds formed by the interaction between the added conductive fillers and the resin matrix improve the dispersibility of the conductive fillers, increase the rigidity of the matrix molecules, and improve the cohesion of the adhesive.

Claims

1. An acrylate conductive composite pressure-sensitive adhesive, characterized in that, Its raw material A includes: 5 - 15 parts of acrylate polymer; 0.10 - 1.00 part of epoxy resin; 1.0 - 10.0 parts of aniline; 0.1 - 1.0 part of initiator; 1 - 5 parts of conductive particles; 0.010 - 0.100 part of amine curing agent; Wherein: the acrylate polymer is prepared by the following method: after mixing raw material B, polymerization is carried out to obtain it; The raw material B includes: 40 - 60 parts of isooctyl acrylate; 25 - 50 parts of butyl acrylate; 10 - 20 parts of glycidyl methacrylate; 1 - 10 parts of acrylic acid; 1 - 10 parts of 2 - hydroxyethyl methacrylate; 0.1 - 1.0 part of dodecyl mercaptan; 0.1 - 5.0 parts of initiator.

2. The acrylate conductive composite pressure-sensitive adhesive according to claim 1, wherein In the raw material B, the number of parts of isooctyl acrylate is 50 parts; And / or, in the raw material B, the number of parts of butyl acrylate is 25 - 50 parts, such as 25 parts or 50 parts; Preferably, in the raw material B, the mass ratio of isooctyl acrylate to butyl acrylate is (1 - 2):

1.

3. The acrylate conductive composite pressure-sensitive adhesive according to claim 1, wherein In the raw material B, the number of parts of glycidyl methacrylate is 10 - 15 parts, such as 12.5 parts or 15 parts; And / or, in the raw material B, the number of parts of acrylic acid is 1 - 5 parts, such as 3.5 parts or 5 parts; And / or, in the raw material B, the number of parts of 2 - hydroxyethyl methacrylate is 1 - 5 parts, such as 3.5 parts.

4. The acrylate conductive composite pressure-sensitive adhesive according to claim 1, wherein In the raw material B, the number of parts of dodecyl mercaptan is 0.1 - 0.5 part, such as 0.3 part; And / or, in the raw material B, the initiator is benzoyl peroxide; And / or, in the raw material B, the number of parts of the initiator is 0.1 - 3 parts, such as 1 part.

5. The acrylate conductive composite pressure-sensitive adhesive according to claim 1, wherein In the raw material B, a solvent is also included; The number of parts of the solvent can be 100 parts; The solvent can be ethyl acetate.

6. The acrylate conductive composite pressure-sensitive adhesive according to any one of claims 1-5, characterized in that, The preparation method of the acrylate polymer includes the following steps: S1, mix the raw material B in reaction vessel 1 to obtain mixture A; S2, slowly drip 20 - 40% of the weight parts of the mixture A into reaction vessel 2, the dripping time is 0.5 - 4h, then keep the temperature at 70 - 80°C for heat - preservation reaction for 0.2 - 0.4h to obtain mixture B; S3, add the remaining mixture A into mixture B, heat to 70 - 80°C, and react for 1 - 5h to obtain the acrylate polymer.

7. The acrylate conductive composite pressure-sensitive adhesive according to claim 1, characterized in that, In the raw material A, the number of parts of the acrylate polymer is 10 parts; And / or, in the raw material A, the number of parts of the epoxy resin is 0.25 part, 0.50 part, 0.75 part or 1.00 part; And / or, in the raw material A, the average molecular weight of the epoxy resin is 350 - 400, such as 375.86; the epoxy equivalent is 175 - 200 g / eq, such as the epoxy equivalent is 184 - 194 g / eq.

8. The acrylate conductive composite pressure-sensitive adhesive according to claim 7, characterized in that, In the raw material A, the epoxy resin is E51 glycidyl ether - type epoxy resin purchased from Baling Petrochemical.

9. The acrylate conductive composite pressure-sensitive adhesive according to claim 1, wherein In the raw material A, the number of parts of aniline is 2.5 parts, 5.0 parts, 7.5 parts or 10.0 parts; And / or, in the raw material A, the number of parts of the initiator is 0.5 part; And / or, in the raw material A, the type of the initiator is ammonium persulfate; And / or, in the raw material A, the amount of the conductive particles is 3 parts; And / or, in the raw material A, the type of the conductive particles is nano nickel; And / or, in the raw material A, the amounts of the amine curing agent are 0.025 part, 0.050 part, 0.075 part or 0.100 part.

10. A method for preparing the acrylate conductive composite pressure-sensitive adhesive according to any one of claims 1-9, characterized in that, It comprises the following steps: (1) Mix the acrylate polymer, the epoxy resin and the aniline to obtain a mixture 1; dissolve the initiator APS in a solvent to obtain a mixture 2; mix and react the mixture 2 and the mixture 1 to obtain a mixture 3; (2) Mix the mixture 3, the conductive particles and the amine curing agent to obtain a mixture 4, and cure the mixture 4 to obtain the acrylate conductive composite pressure-sensitive adhesive.

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