Anisotropic conductive adhesive with high interface connection strength and preparation method thereof

Abstract

The present invention belongs to the technical field of anisotropic conductive adhesives and relates to an anisotropic conductive adhesive with high interface bonding strength and a preparation method thereof. The present invention discloses an anisotropic conductive adhesive with high interface bonding strength. The raw materials of the anisotropic conductive adhesive with high interface bonding strength include, by weight, 16 to 25 parts of butyl rubber, 30 to 45 parts of versatate-modified 2-hydroxyethyl methacrylate phosphate, 4 to 10 parts of conductive particles, 25 to 30 parts of silicon dioxide, 30 to 40 parts of titanium dioxide, 20 to 30 parts of solvent, and 1 to 5 parts of initiator BPO; the content of the versatate-modified 2-hydroxyethyl methacrylate phosphate is 18 to 30%. The present invention also discloses a preparation method of the anisotropic conductive adhesive with high interface bonding strength.

Description

Technical Field

[0001] The invention belongs to the technical field of anisotropic conductive adhesives and relates to anisotropic conductive adhesive with high interface connection strength and a preparation method thereof. Background Art

[0002] Anisotropic conductive adhesives are core materials used to bond electronic product panels and circuits, providing vertical conductivity and horizontal insulation. Currently, most anisotropic conductive adhesives on the market incorporate polyurethane-acrylates to enhance interfacial connectivity and ensure adhesion. However, the addition of polyurethane-acrylates increases the adhesive's viscosity during mixing, which can affect the dispersion and coating process. Summary of the Invention

[0003] The purpose of the present invention is to address the above-mentioned problems existing in the prior art and to provide an anisotropic conductive adhesive with high interface connection strength and a preparation method thereof, which can control the viscosity during the preparation of the anisotropic conductive adhesive.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A high-interface-connectivity anisotropic conductive adhesive, comprising, by weight, 16 to 25 parts of butyl rubber, 30 to 45 parts of versatate-modified glycidyl ester of 2-hydroxyethyl methacrylate phosphate, 4 to 10 parts of conductive particles, 25 to 30 parts of silicon dioxide, 30 to 40 parts of titanium dioxide, 20 to 30 parts of a solvent, and 1 to 5 parts of an initiator, BPO.

[0006] The content of the tertiary glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate is 18-30%.

[0007] Preferably, the mass ratio of the butyl rubber to the versatile glycidyl ester modified 2-hydroxyethyl methacrylate phosphate is 1:(1.5-2.0).

[0008] Preferably, the raw materials of the versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate include, by weight, 20-30 parts of versatile glycidyl carbonate, 6.3-9.6 parts of acrylic acid, 10-30 parts of 2-hydroxyethyl methacrylate phosphate, and 0.1-1 part of BPO.

[0009] More preferably, the mass ratio of the versatile glycidyl carbonate to acrylic acid is (2.3-2.9):1.

[0010] More preferably, the added amount of the 2-hydroxyethyl methacrylate phosphate is 24-36%.

[0011] Preferably, the preparation method of the versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate comprises: uniformly mixing versatile glycidyl carbonate and acrylic acid, heating to a first reaction temperature for reaction, then adjusting the temperature to a second reaction temperature, dropwise adding a mixture of 2-hydroxyethyl methacrylate phosphate and BPO, and carrying out heat preservation reaction to obtain the product.

[0012] More preferably, the first reaction temperature is higher than the second reaction temperature.

[0013] More preferably, the first reaction temperature is 105-115° C., and the reaction time is 2-5 h; the second reaction temperature is 97-103° C., the dropwise addition time is 0.5-1.5 h, and the insulation time is 1.5-3.5 h.

[0014] More preferably, the reaction time at the first reaction temperature is equal to the sum of the dropwise addition time and the insulation time at the second reaction temperature.

[0015] The present invention also discloses a method for preparing anisotropic conductive adhesive with high interface connection strength, which comprises weighing butyl rubber, 2-hydroxyethyl methacrylate phosphate modified with versatate glycidyl carbonate, and heating a solvent to dissolve the mixture, and then sequentially adding silicon dioxide, titanium dioxide, conductive particles, and an initiator and stirring until the mixture is evenly dispersed.

[0016] Preferably, the heating temperature is 50°C.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention adds tert-butyl glycidyl ester modified 2-hydroxyethyl methacrylate phosphate to the anisotropic conductive adhesive system, introduces a large number of hydroxyl polar groups, and increases the interfacial connection strength of the product while controlling the mixing viscosity during the preparation of the anisotropic conductive adhesive.

[0019] 2. Compared with conventional versatate glycidyl carbonate modified acrylic resin, the versatate glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate of the present invention introduces more polar hydroxyl groups. At the same time, 2-hydroxyethyl methacrylate phosphate has hydrophilic and lipophilic properties, which can improve system compatibility.

[0020] 3. The present invention improves the compatibility of the system by modifying 2-hydroxyethyl methacrylate phosphate with tert-butyl glycidyl carbonate. The phosphate group has hydrophilicity and can connect with water-tolerant substances in the system. The acrylic group provides lipophilic properties and can be compatible or combined with lipophilic substances.

[0021] 4. In the preparation process of versatate glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate, the present invention adjusts the reaction temperature and time of versatate glycidyl carbonate and acrylic acid, and also controls the reaction time to be the same as the sum of the addition time and the holding time of the mixture of 2-hydroxyethyl methacrylate phosphate and BPO to ensure complete modification.

[0022] 5. The preparation process of the present invention is simple and controllable, and is suitable for large-scale production. DETAILED DESCRIPTION

[0023] The following are specific examples of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these examples. Unless otherwise specified, the raw materials used in the present invention are all commercially available materials, and the preparation methods used are all conventional means.

[0024] Example 1

[0025] Preparation of 2-hydroxyethyl methacrylate phosphate modified with tert-butyl glycidyl carbonate:

[0026] Weigh the following raw materials in proportion: 24 parts of versatile glycidyl carbonate (Hubei Zhenbo Chemical Co., Ltd., B1155), 9.2 parts of acrylic acid (MERCK, 147230), 18 parts of 2-hydroxyethyl methacrylate phosphate (MERCK, 695890), and 0.3 parts of BPO;

[0027] The content of 2-hydroxyethyl methacrylate phosphate is 35.0%; the mass ratio of versatate glycidyl carbonate to 2-hydroxyethyl methacrylate phosphate is 2.61:1;

[0028] After mixing tert-butyl glycidyl carbonate and acrylic acid, heat to 110° C. and react for 3 hours; then cool to 100° C. and add a mixture of 2-hydroxyethyl methacrylate phosphate and BPO dropwise under magnetic stirring for 1 hour. After the addition is completed, keep the mixture at 100° C. for 2 hours to obtain tert-butyl glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate.

[0029] Preparation of anisotropic conductive adhesive with high interfacial connection strength:

[0030] Weigh the following raw materials in proportion: butyl rubber 20 parts, versatate glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate 33 parts, conductive particles 6 parts, silicon dioxide 28 parts, titanium dioxide 34 parts, solvent (toluene) 26 parts, initiator BPO 3 parts;

[0031] The content of versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate is 22.0%; the mass ratio of butyl rubber to versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate is 1:1.65;

[0032] Butyl rubber, versatate glycidyl ester-modified 2-hydroxyethyl methacrylate phosphate, and solvent are weighed into a container, mixed, and heated to 50°C until completely dissolved; then silicon dioxide and titanium dioxide are added and mixed, and then conductive particles are added, and finally an initiator is added, and the mixture is placed in a defoaming mixer and dispersed evenly to obtain anisotropic conductive adhesive with high interfacial connection strength.

[0033] The viscosity of the anisotropic conductive adhesive with high interface connection strength is shown in Table 1. The anisotropic conductive adhesive with high interface connection strength is made and used to connect PCB circuit substrates. The interface connection strength and on-resistance are shown in Table 1.

[0034] Example 2

[0035] Compared with Example 1, the difference is that the raw materials of versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate include: 27 parts of versatile glycidyl carbonate, 9.4 parts of acrylic acid, 15 parts of 2-hydroxyethyl methacrylate phosphate, and 0.1 part of BPO;

[0036] The content of 2-hydroxyethyl methacrylate phosphate is 29.1%; the mass ratio of versatate glycidyl carbonate to 2-hydroxyethyl methacrylate phosphate is 2.87:1.

[0037] Example 3

[0038] Compared with Example 1, the difference is that the raw materials of versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate include: 29 parts of versatile glycidyl carbonate, 8.2 parts of acrylic acid, 14 parts of 2-hydroxyethyl methacrylate phosphate, and 0.3 parts of BPO;

[0039] The content of 2-hydroxyethyl methacrylate phosphate is 27.2%; the mass ratio of versatate glycidyl ester to 2-hydroxyethyl methacrylate phosphate is 3.54:1.

[0040] Example 4

[0041] Compared with Example 1, the difference is that the raw materials of versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate include: 23 parts of versatile glycidyl carbonate, 8.2 parts of acrylic acid, 20 parts of 2-hydroxyethyl methacrylate phosphate, and 0.3 parts of BPO;

[0042] The content of 2-hydroxyethyl methacrylate phosphate is 38.8%; the mass ratio of versatate glycidyl carbonate to 2-hydroxyethyl methacrylate phosphate is 2.80:1.

[0043] Example 5

[0044] Compared with Example 1, the difference is that the raw materials of versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate include: 21 parts of versatile glycidyl carbonate, 9.2 parts of acrylic acid, 21 parts of 2-hydroxyethyl methacrylate phosphate, and 0.3 parts of BPO;

[0045] The content of 2-hydroxyethyl methacrylate phosphate is 40.8%; the mass ratio of versatate glycidyl carbonate to 2-hydroxyethyl methacrylate phosphate is 2.28:1.

[0046] Example 6

[0047] Compared with Example 1, the difference is that the raw materials of the anisotropic conductive adhesive with high interface connection strength include: 20 parts of butyl rubber, 39 parts of 2-hydroxyethyl methacrylate phosphate modified with versatate glycidyl ester, 6 parts of conductive particles, 26 parts of silicon dioxide, 30 parts of titanium dioxide, 26 parts of solvent (toluene), and 3 parts of initiator BPO.

[0048] The content of versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate is 26.0%; the mass ratio of butyl rubber to versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate is 1:1.95.

[0049] Example 7

[0050] Compared with Example 1, the difference is that the preparation process of tert-butyl glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate includes:

[0051] After mixing tert-butyl glycidyl carbonate and acrylic acid, heat to 100° C. and react for 3 hours; then cool to 100° C. and add a mixture of 2-hydroxyethyl methacrylate phosphate and BPO dropwise under magnetic stirring for 1 hour. After the addition is completed, keep the mixture at 100° C. for 2 hours to obtain tert-butyl glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate.

[0052] Example 8

[0053] Compared with Example 1, the difference is that the preparation process of tert-butyl glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate includes:

[0054] After mixing tert-butyl glycidyl carbonate and acrylic acid, heat to 110° C. and react for 3 hours; then cool to 100° C. and add a mixture of 2-hydroxyethyl methacrylate phosphate and BPO dropwise under magnetic stirring for 1 hour. After the addition is completed, keep the mixture at 100° C. for 0.5 hour to obtain tert-butyl glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate.

[0055] Comparative Example 1

[0056] In this comparative example, conventional versatate glycidyl carbonate-modified acrylic resin is used instead of versatate glycidyl carbonate-modified 2-hydroxyethyl methacrylate phosphate in Example 1 of the present invention.

[0057] The preparation process of the versatile glycidyl carbonate modified acrylic resin includes: using versatile glycidyl carbonate as the bottom of a kettle, dropwise adding an acrylic monomer mixture including acrylic acid, methacrylic acid, and hydroxyethyl methacrylate, and an initiator di-tert-amyl peroxide, reacting at a temperature of 140° C. for 4 hours, keeping the temperature for 2 hours, cooling to 90° C., and adding dimethylethanolamine and deionized water for neutralization and dispersion.

[0058] Comparative Example 2

[0059] Compared with Example 1, the difference is that the raw materials of the anisotropic conductive adhesive with high interface connection strength include: 20 parts of butyl rubber, 45 parts of 2-hydroxyethyl methacrylate phosphate modified with versatate glycidyl ester, 6 parts of conductive particles, 25 parts of silicon dioxide, 30 parts of titanium dioxide, 21 parts of solvent (toluene), and 3 parts of initiator BPO.

[0060] The content of versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate is 30.0%; the mass ratio of butyl rubber to versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate is 1:2.25.

[0061] Comparative Example 3

[0062] Compared with Example 1, the difference is that the raw materials of the anisotropic conductive adhesive with high interface connection strength include: 25 parts of butyl rubber, 25 parts of 2-hydroxyethyl methacrylate phosphate modified with versatate glycidyl ester, 6 parts of conductive particles, 28 parts of silicon dioxide, 37 parts of titanium dioxide, 26 parts of solvent (toluene), and 3 parts of initiator BPO.

[0063] The content of versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate is 16.7%; and the mass ratio of butyl rubber to versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate is 1:1.

[0064] The viscosity of the anisotropic conductive adhesive with high interface connection strength is shown in Table 1. The anisotropic conductive adhesive with high interface connection strength is made and used to connect PCB circuit substrates. The interface connection strength and on-resistance are shown in Table 1.

[0065] Table 1. Anisotropic conductive film performance data

[0066]

[0067]

[0068] According to the above table, the anisotropic conductive adhesives with high interface connection strength prepared in Examples 1, 2, and 6 of the present invention have lower viscosity, higher interface connection strength, and lower on-resistance.

[0069] In Example 3, too little tert-butyl glycidyl carbonate and acrylic acid in acrylic acid resulted in a large amount of free tert-butyl glycidyl carbonate in the base system, which reduced the bonding strength of the prepared anisotropic conductive adhesive and increased the on-resistance.

[0070] In Example 4, the content of 2-hydroxyethyl methacrylate phosphate is relatively high, resulting in an increase in viscosity;

[0071] In Example 5, there is too much tert-butyl glycidyl carbonate and acrylic acid in the acrylic acid, and the content of 2-hydroxyethyl methacrylate phosphate is relatively high, resulting in increased viscosity and decreased adhesion;

[0072] In Example 7, during the preparation of tert-butyl glycidyl ester-modified 2-hydroxyethyl methacrylate phosphate, the reaction temperature remained unchanged, resulting in a slight increase in viscosity, a slight decrease in adhesion, and an increase in on-resistance;

[0073] In Example 8, during the preparation of tert-butyl glycidyl ester-modified 2-hydroxyethyl methacrylate phosphate, the reaction time for adding the mixture of 2-hydroxyethyl methacrylate phosphate and BPO was relatively short, resulting in a certain degree of deterioration in viscosity, adhesion, and on-resistance.

[0074] In Comparative Example 1, the conventional versatile glycidyl carbonate modified acrylic resin resulted in increased viscosity, decreased adhesion, and increased on-resistance. Furthermore, the preparation process temperature of the conventional versatile glycidyl carbonate modified acrylic resin was 140° C., which was not suitable for the preparation conditions of the present invention.

[0075] In Comparative Example 2, the high content of tert-butyl glycidyl ester-modified 2-hydroxyethyl methacrylate phosphate in the anisotropic conductive adhesive system leads to a decrease in the skeleton material and reduced adhesive toughness. At the same time, excessive 2-hydroxyethyl methacrylate phosphate increases the connection force between various substances, thereby reducing the interfacial connection force and increasing the viscosity.

[0076] In Comparative Example 3, the low content of tert-butyl glycidyl ester-modified 2-hydroxyethyl methacrylate phosphate in the anisotropic conductive adhesive system leads to poor system compatibility. Meanwhile, the addition of too many backbone macromolecules deteriorates the fluidity of the system, thereby reducing the interfacial connection force and increasing the viscosity.

[0077] In summary, the present invention adds tert-butyl glycidyl ester-modified 2-hydroxyethyl methacrylate phosphate to the anisotropic conductive adhesive system, introduces a large number of hydroxyl polar groups, and increases the interfacial connection strength of the product while controlling the viscosity during the preparation of the anisotropic conductive adhesive.

[0078] 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. An anisotropic conductive adhesive with high interface connection strength, characterized in that: The raw materials of the anisotropic conductive adhesive with high interface connection strength include, by weight, 16 to 25 parts of butyl rubber, 30 to 45 parts of versatate glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate, 4 to 10 parts of conductive particles, 25 to 30 parts of silicon dioxide, 30 to 40 parts of titanium dioxide, 20 to 30 parts of solvent, and 1 to 5 parts of initiator BPO; the mass ratio of the butyl rubber to the versatate glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate is 1:(1.5 to 2.0); The content of the tert-butyl glycidyl ester modified 2-hydroxyethyl methacrylate phosphate is 18-30%; The raw materials of the versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate include, by weight: 20-30 parts of versatile glycidyl carbonate, 6.3-9.6 parts of acrylic acid, 10-30 parts of 2-hydroxyethyl methacrylate phosphate, and 0.1-1 part of BPO; The preparation method of versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate comprises: uniformly mixing versatile glycidyl carbonate and acrylic acid, heating to a first reaction temperature for reaction, adjusting the temperature to a second reaction temperature, dropwise adding a mixture of 2-hydroxyethyl methacrylate phosphate and BPO, and carrying out heat preservation reaction to obtain the product.

2. The anisotropic conductive adhesive with high interface connection strength according to claim 1, characterized in that: The mass ratio of the tert-butyl glycidyl ester to acrylic acid is (2.3-2.9):

1.

3. The anisotropic conductive adhesive with high interface connection strength according to claim 1, characterized in that: The addition amount of the 2-hydroxyethyl methacrylate phosphate is 24-36%.

4. The anisotropic conductive adhesive with high interface connection strength according to claim 1, characterized in that: The first reaction temperature is higher than the second reaction temperature.

5. The anisotropic conductive adhesive with high interface connection strength according to claim 1, characterized in that: The first reaction temperature is 105-115° C., and the reaction time is 2-5 h; the second reaction temperature is 97-103° C., the dropwise addition time is 0.5-1.5 h, and the insulation time is 1.5-3.5 h.

6. The anisotropic conductive adhesive with high interface connection strength according to claim 5, characterized in that: The reaction time at the first reaction temperature is equal to the sum of the dropwise addition time and the insulation time at the second reaction temperature.

7. A method for preparing anisotropic conductive adhesive with high interface connection strength as claimed in claim 1, characterized in that: The preparation method comprises: weighing butyl rubber, versatile glycidyl carbonate modified 2-hydroxyethyl methacrylate phosphate, and a solvent, heating and dissolving them, and then sequentially adding silicon dioxide, titanium dioxide, conductive particles, and an initiator and stirring until they are evenly dispersed.

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