A reactive anisotropic conductive adhesive and its preparation method and application

Abstract

The present invention belongs to the technical field of anisotropic conductive adhesives and relates to a reactive anisotropic conductive adhesive, its preparation method, and application. The present invention discloses a reactive anisotropic conductive adhesive, which comprises the following raw materials, by weight: 10 to 15 parts of butyl rubber, 25 to 45 parts of polyurethane-acrylate, 30 to 80 parts of compounding monomer, 1 to 10 parts of conductive particles, 10 to 30 parts of silicon dioxide, 1 to 10 parts of titanium dioxide, 1 to 10 parts of initiator BPO, and 0 to 20 parts of other additives. The present invention also discloses a preparation method of the reactive anisotropic conductive adhesive and its application in the field of electronic device packaging.

Description

Technical Field

[0001] The invention belongs to the technical field of anisotropic conductive adhesives and relates to a reactive anisotropic conductive adhesive and a preparation method and application thereof. Background Art

[0002] Currently, anisotropic conductive adhesives (ACFs) on the market primarily enhance the cohesion and adhesion of the ACF adhesive by adding a curing agent that reacts with the resin, while also increasing the strength of the resin backbone. However, this approach can result in an incomplete reaction, and residual curing agent and small-molecule resin can significantly impact the adhesive's performance. Furthermore, insufficient adhesion can weaken the adhesive's conductivity during application, impacting device performance. Therefore, research is ongoing to develop anisotropic conductive adhesives with high adhesion.

[0003] Existing technologies typically increase bonding strength and long-term stability by changing the bonding structure. For example, a Chinese patent application (publication number CN107172825A) discloses an attachment structure for a flexible printed circuit board and a fingerprint recognition sensor, wherein a hollow portion having a shape that matches that of the anisotropic conductive film and that completely penetrates the adhesive film from top to bottom is provided in the middle of the adhesive film. This means that the anisotropic conductive film achieves higher adhesion through the aid of the highly viscous adhesive film. However, this method is not suitable for bonding small structures and does not fundamentally solve the problem of insufficient adhesion. Summary of the Invention

[0004] The purpose of the present invention is to address the above-mentioned problems existing in the prior art and to provide a reactive anisotropic conductive adhesive with high viscosity that is cross-linked by a compounded monomer.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A reactive anisotropic conductive adhesive comprises the following raw materials in parts by weight: 10 to 15 parts of butyl rubber, 25 to 45 parts of polyurethane-acrylate, 30 to 80 parts of compounded monomers, 1 to 10 parts of conductive particles, 10 to 30 parts of silicon dioxide, 1 to 10 parts of titanium dioxide, 1 to 10 parts of initiator BPO, and 0 to 20 parts of other additives.

[0007] Preferably, the compounded monomers are 5 to 20 parts of trifunctional isocyanurate (triallyl isocyanurate), 10 to 30 parts of difunctional isocyanurate, and 20 to 35 parts of monofunctional isocyanurate.

[0008] The present invention uses three isocyanurates with different functionalities for compounding, and adopts monomer polymerization to increase the modulus and cohesion of the anisotropic conductive adhesive, which is beneficial to improving the adhesion. Compared with a single trifunctional isocyanurate, the compounding of isocyanurates with different functionalities can adjust the crosslinking degree through different ratios, control the reaction process and polymer molecular weight. In addition, the present invention uses three isocyanurates with different functionalities to replace part of the thermosetting resin, which can also strengthen the resin skeleton strength. The carbon-nitrogen six-membered ring structure carried in the compounded monomer can enhance the polymer strength and the adhesion to the substrate surface.

[0009] Preferably, the mass ratio of the butyl rubber, polyurethane-acrylate and compound monomer is 1:(2-4):(3-8).

[0010] Preferably, the mass ratio of the trifunctional isocyanurate, the difunctional isocyanurate, and the monofunctional isocyanurate is 1:(0.8-4):(2-5).

[0011] Preferably, the polar groups in the composite monomer include -NCO, -OH, -NH, and -COOR-, and the total number of polar groups is 13.

[0012] Preferably, the molecular weight of the butyl rubber is 100,000 to 300,000.

[0013] The present invention also discloses a method for preparing a reactive anisotropic conductive adhesive, which comprises: mixing trifunctional isocyanurate, difunctional isocyanurate, and monofunctional isocyanurate with a solvent, adding butyl rubber and polyurethane-acrylate, heating and dissolving them, then adding the remaining raw materials, and stirring and dispersing them evenly to obtain the reactive anisotropic conductive adhesive.

[0014] Preferably, the heating temperature is 45-60°C.

[0015] Preferably, the solvent is toluene.

[0016] The invention also discloses the application of reactive anisotropic conductive adhesive in the field of electronic device packaging.

[0017] Preferably, the reactive anisotropic conductive adhesive has a peeling force of 850 to 1000 g / cm in a small-sized structure.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention uses three isocyanurates with different functionalities for compounding. The modulus and cohesion of the anisotropic conductive adhesive are increased by monomer polymerization, which is beneficial to increasing the adhesion. Compared with a single trifunctional isocyanurate, the compounding of isocyanurates with different functionalities can adjust the crosslinking degree through different ratios, control the reaction process and polymer molecular weight.

[0020] 2. The present invention uses low-viscosity polyurethane-acrylate (PUA) and high-molecular-weight butyl rubber, mixed with compound monomers to improve the bonding performance of the anisotropic conductive adhesive, which is more suitable for small-sized structures.

[0021] 3. The preparation method of the present invention is simple and controllable and can be produced on a large scale. DETAILED DESCRIPTION

[0022] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0023] The raw materials used in the present invention are all commercially available products.

[0024] in

[0025] Trifunctional isocyanurate (molecular weight 2498; CAS: 1025-15-6; 3 -NCO polar groups);

[0026] Difunctional isocyanurate (molecular weight 369; CAS: 67893-00-9; 3 -NCO polar groups, 1 -OH polar group, 2 -COOR- polar groups);

[0027] Monofunctional isocyanurate (molecular weight 228; CAS: 88403-03-6; 1 -NCO polar group, 2 -NH polar groups, 1 -COOR- polar group);

[0028] Polyurethane-acrylate (model Ebecryl8210).

[0029] Example 1

[0030] The reactive anisotropic conductive adhesive in this embodiment includes the following raw materials by weight: 12 parts of butyl rubber, 33 parts of polyurethane-acrylate, 10 parts of trifunctional isocyanurate, 15 parts of difunctional isocyanurate, 25 parts of monofunctional isocyanurate, 2 parts of conductive particles, 12 parts of silicon dioxide, 2 parts of titanium dioxide, and 2 parts of initiator BPO.

[0031] The raw materials are accurately weighed in proportion, trifunctional isocyanurate, difunctional isocyanurate, and monofunctional isocyanurate are first mixed with toluene, and then butyl rubber and polyurethane-acrylate are added. Heat at 50°C to dissolve, and then the remaining raw materials are added. Stir and disperse evenly to obtain a reactive anisotropic conductive adhesive.

[0032] The prepared reactive anisotropic conductive adhesive had a thickness of 40 μm and was applied by bonding it (size 2*30 nm) between glass substrates to test the peel strength. Specific results are shown in Table 1.

[0033] Example 2

[0034] Compared with Example 1, the difference lies in the following raw materials: 13 parts of butyl rubber, 32 parts of polyurethane-propylene ester, 8 parts of trifunctional isocyanurate, 20 parts of difunctional isocyanurate, and 22 parts of monofunctional isocyanurate.

[0035] Example 3

[0036] Compared with Example 1, the difference is that the compound monomer in the raw materials is 20 parts of difunctional isocyanurate and 30 parts of monofunctional isocyanurate.

[0037] Example 4

[0038] Compared with Example 1, the difference is that the compound monomer in the raw materials is 15 parts of trifunctional isocyanurate and 35 parts of monofunctional isocyanurate.

[0039] Example 5

[0040] Compared with Example 1, the difference is that the compound monomer in the raw materials is 20 parts of trifunctional isocyanurate and 30 parts of difunctional isocyanurate.

[0041] Example 6

[0042] Compared with Example 1, the difference is that the monomer is only 50 parts of monofunctional isocyanurate.

[0043] Example 7

[0044] Compared with Example 1, the difference is that the monomer is only 50 parts of difunctional isocyanurate.

[0045] Example 8

[0046] Compared with Example 1, the difference is that the monomer is only 50 parts of trifunctional isocyanurate.

[0047] Example 9

[0048] Compared with Example 1, the difference is that the compounded monomers are 10 parts of trifunctional isocyanurate, 18 parts of difunctional isocyanurate, and 22 parts of monofunctional isocyanurate.

[0049] Example 10

[0050] Compared with Example 1, the difference is that the compounded monomers are 8 parts of trifunctional isocyanurate, 20 parts of difunctional isocyanurate, and 22 parts of monofunctional isocyanurate.

[0051] Example 11

[0052] Compared with Example 1, the difference is that the compounded monomers are 10 parts of trifunctional isocyanurate, 20 parts of difunctional isocyanurate and 20 parts of monofunctional isocyanurate.

[0053] Example 12

[0054] Compared with Example 1, the difference is that the compounded monomers are 5 parts of trifunctional isocyanurate, 30 parts of difunctional isocyanurate, and 15 parts of monofunctional isocyanurate.

[0055] Example 13

[0056] Compared with Example 1, the difference is that the compounded monomers are 21 parts of trifunctional isocyanurate, 10 parts of difunctional isocyanurate, and 19 parts of monofunctional isocyanurate.

[0057] Example 14

[0058] Compared with Example 1, the difference is that the raw materials contain 11 parts of butyl rubber, 34 parts of polyurethane-acrylate, and 50 parts of compound monomer.

[0059] Example 15

[0060] Compared with Example 1, the difference is that the raw materials contain 10 parts of butyl rubber, 35 parts of polyurethane-acrylate, and 50 parts of compound monomer.

[0061] Example 16

[0062] Compared with Example 1, the difference is that the raw materials contain 8 parts of butyl rubber, 37 parts of polyurethane-acrylate, and 50 parts of compound monomer.

[0063] Example 17

[0064] Compared with Example 1, the difference is that the raw materials contain 14 parts of butyl rubber, 31 parts of polyurethane-acrylate, and 50 parts of compound monomer.

[0065] Example 18

[0066] Compared with Example 1, the difference is that the raw materials contain 15 parts of butyl rubber, 30 parts of polyurethane-acrylate, and 50 parts of compound monomer.

[0067] Example 19

[0068] Compared with Example 1, the difference is that the raw materials contain 16 parts of butyl rubber, 29 parts of polyurethane-acrylate, and 50 parts of compound monomer.

[0069] Example 20

[0070] Compared with Example 1, the difference is that the raw materials contain 8 parts of butyl rubber, 37 parts of polyurethane-acrylate, and 50 parts of compound monomer.

[0071] Example 21

[0072] Compared with Example 1, the difference is that the raw materials contain 17 parts of butyl rubber, 28 parts of polyurethane-acrylate, and 50 parts of compound monomer.

[0073] Example 22

[0074] Compared with Example 1, the difference is that the raw materials contain 25 parts of butyl rubber, 20 parts of polyurethane-acrylate, and 50 parts of compound monomer.

[0075] Comparative Example 1

[0076] Compared with Example 1, the difference is that the raw materials do not include the compound monomer.

[0077] Comparative Example 2

[0078] Compared with Example 1, the difference is that tris(2-hydroxyethyl)isocyanurate triacrylate (CAS: 40220-08-4; C 28 H 21 N3O9).

[0079] Comparative Example 3

[0080] Compared with Example 1, the difference is that nine-functionality polyurethane acrylate is used.

[0081] Table 1. Performance data of reactive anisotropic conductive adhesive

[0082]

[0083]

[0084] The reactive anisotropic conductive adhesives prepared in Examples 1 to 22 were used to connect small-sized (2*30nm) FPCs to panels. Performance tests showed that they could still maintain 90-98% peel force performance (850-1000g / cm). Among them, the reactive anisotropic conductive adhesive in Example 1 could maintain 98% peel force (about 1000g / cm).

[0085] In summary, the present invention uses three isocyanurates with different functionalities for compounding, and increases the modulus and cohesion of the anisotropic conductive adhesive through monomer polymerization, which is beneficial to increasing the adhesion. Compared with a single trifunctional isocyanurate, the compounding of isocyanurates with different functionalities can adjust the crosslinking degree through different ratios, control the reaction process and polymer molecular weight; and control the composition and proportion of each raw material to improve the cohesion and peel strength of the anisotropic conductive adhesive.

[0086] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A reactive anisotropic conductive adhesive, characterized in that: The reactive anisotropic conductive adhesive comprises the following raw materials, calculated by weight: 10-15 parts of butyl rubber, 25-45 parts of polyurethane-acrylate, 30-80 parts of compounded monomers, 1-10 parts of conductive particles, 10-30 parts of silicon dioxide, 1-10 parts of titanium dioxide, 1-10 parts of initiator BPO, and 0-20 parts of other additives; The compound monomers are 5 to 15 parts of trifunctional isocyanurate, 10 to 25 parts of difunctional isocyanurate, and 20 to 35 parts of monofunctional isocyanurate.

2. The reactive anisotropic conductive adhesive according to claim 1, characterized in that: The mass ratio of the trifunctional isocyanurate, the difunctional isocyanurate and the monofunctional isocyanurate is 1:(0.8-4):(2-5).

3. The reactive anisotropic conductive adhesive according to claim 1, characterized in that: The mass ratio of the butyl rubber, polyurethane-acrylate and compound monomer is 1:(2-4):(3-8).

4. The reactive anisotropic conductive adhesive according to claim 1, characterized in that: The polar groups in the compound monomer include -NCO, -OH, and -NH-.

5. The reactive anisotropic conductive adhesive according to claim 4, characterized in that: The total number of polar groups in the composite monomer is 13.

6. The reactive anisotropic conductive adhesive according to claim 1, characterized in that: The molecular weight of the butyl rubber is 100,000-300,000.

7. A method for preparing a reactive anisotropic conductive adhesive as claimed in claim 1, characterized in that: The preparation method comprises: mixing trifunctional isocyanurate, difunctional isocyanurate, and monofunctional isocyanurate with a solvent, adding butyl rubber and polyurethane-acrylate, heating to dissolve, adding the remaining raw materials, and stirring and dispersing them uniformly to obtain a reactive anisotropic conductive adhesive.

8. The preparation method according to claim 7, characterized in that The heating temperature is 45~60℃.

9. The preparation method according to claim 7, characterized in that The solvent is toluene.

10. Use of the reactive anisotropic conductive adhesive according to claim 1 in the field of electronic device packaging.

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