Anti-water-absorption ACF conductive adhesive tape and preparation process thereof

Abstract

The invention relates to the technical field of conductive adhesives, and discloses an anti-water-absorption ACF conductive adhesive tape, which comprises a release film layer and an adhesive film layer coated on the upper surface of the release layer, the adhesive film layer comprises the following components in parts by weight: 30-35 parts of film-forming resin, 35-40 parts of a main reaction monomer, 5-8 parts of rubber, 3-5 parts of conductive particles, 9-11 parts of filler, 3-6 parts of an auxiliary agent, 0.1-0.5 part of a polymerization inhibitor and 1.0-3.5 parts of an initiator. The invention further discloses a preparation process of the anti-water-absorption ACF conductive adhesive tape. According to the invention, the self-synthesized polycarbonate polyurethane is added into the main reaction monomer, has the advantages of polyester and polyether, and has the advantages of good flexibility, stress relief, improvement of interface bonding force, hydrolysis resistance and high mechanical strength, so that the water resistance and impact resistance of the ACF conductive adhesive are improved.

Description

Technical Field

[0001] The invention relates to the technical field of conductive adhesives, in particular to an ACF conductive adhesive tape that resists water absorption and a preparation process thereof. Background Art

[0002] As electronic devices become increasingly miniaturized, high-precision and high-performance, traditional soldering technology can no longer meet the requirements of microelectronic packaging. Anisotropic conductive adhesive (ACF) has emerged as a new type of electronic packaging adhesive material.

[0003] Compared with traditional soldering materials, ACF has the advantages of being environmentally friendly, having a small bonding spacing, a simple operation process, and a low processing temperature. However, ACF easily absorbs moisture and undergoes thermal degradation, and cyclic thermal stress and hygroscopic stress accumulate cyclically. Trace amounts of water in ACF may play two roles in the conductive adhesive system: swelling and plasticization. The plasticizing effect of water on the conductive adhesive can reduce the resin bonding strength, glass transition temperature, and elastic modulus. The swelling effect of water can cause swelling stress in ACF, and even irreversible changes. Moreover, water can corrode the interface between ACF and electronic devices, thereby reducing the bonding stability. For metals that are prone to electromigration, water can also accelerate their electromigration speed. Therefore, trace amounts of water may cause a significant decrease in the performance of the conductive adhesive, making ACF prone to plastic deformation, which in turn leads to rapid failure of the interface, which shortens the fatigue life of the ACF joint.

[0004] Therefore, the development of high-performance ACF is crucial to the development of electronic packaging technology and even the entire electronic device industry, and there is an urgent need to develop an ACF conductive tape that is resistant to water absorption. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides an ACF conductive tape with water absorption resistance and a preparation process thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A water-absorption resistant ACF conductive tape comprises a release film layer and an adhesive film layer coated on the upper surface of the release layer; the adhesive film layer comprises the following components in parts by weight: 30-35 parts of film-forming resin, 35-40 parts of main reaction monomers, 5-8 parts of rubber, 3-5 parts of conductive particles, 9-11 parts of fillers, 3-6 parts of additives, 0.1-0.5 parts of inhibitors, and 1.0-3.5 parts of initiators.

[0008] Preferably, the adhesive film layer comprises the following components in parts by weight: 32 parts of film-forming resin, 38.8 parts of main reaction monomer, 7 parts of rubber, 5 parts of conductive particles, 10.5 parts of filler, 4 parts of auxiliary agent, 0.3 parts of inhibitor, and 2.4 parts of initiator.

[0009] Preferably, the thickness of the adhesive film layer is 20-50 um.

[0010] Preferably, the main reaction monomer is a mixture of six monomers: commercial polycarbonate polyurethane monomer, self-synthesized polycarbonate polyurethane monomer, isocyanuric acid acrylate monomer, 4-hydroxybutyl acrylate monomer, polyester acrylate monomer, and 2-[(2-propylene-1-yloxy)methyl]-2-methyl acrylate monomer.

[0011] Preferably, the self-synthesized polycarbonate polyurethane monomer is synthesized by the following steps:

[0012] Accurately weigh 70.0 g of polycarbonate polyol in a reactor, cover the reactor lid, install a jacketed reactor, and ensure that the reactor is airtight; raise the temperature in the reactor to 120±1°C, stir at a speed of 120±5RPM, and evacuate for 30±1min; cool the materials in the reactor to 90°C, pass N2, add 0.1 g of dibutyltin dilaurate as a catalyst, stir at a speed of 120±5RPM, and stir for 15±1min; add 30.0 g of diisocyanate, stir for 6h±10min; add hydroxyl acrylate monomer, stir for 6h±10min, stop stirring after the reaction, and cool to room temperature to obtain a polycarbonate polyurethane monomer.

[0013] Preferably, the film-forming resin is a phenoxy resin; the rubber is a terminal hydroxy-nitrile rubber; the filler is fumed silica and titanium dioxide, the auxiliary agent is a silane coupling agent and 2-(methyl)acryloyloxyethyl phosphate, the inhibitor is bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate and p-tert-butylcatechol, and the initiator is 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate.

[0014] Preferably, the conductive particles are any one of silicon-plated nickel and nickel powder.

[0015] Preferably, the particle size of the conductive particles is 3-5 um.

[0016] The conductive particles are preferably spherical particles with good regularity.

[0017] Another object of the present invention is to disclose a preparation process of the above-mentioned anti-water absorption ACF conductive tape, comprising the following steps:

[0018] (1) The main reaction monomer and the filler are mixed uniformly by a three-roll mill to prepare a pre-mixed material A;

[0019] (2) Pre-mixing material A, film-forming resin and rubber at 60-80° C. and a rotation speed of 150 r / min to prepare pre-mixing material B;

[0020] (3) Add conductive particles, additives, inhibitors and initiators to the pre-prepared material B, stir evenly to obtain a film material, heat the film material and apply it on the release paper to form a film layer through a coating machine, and cool and dry to obtain an ACF conductive tape.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention adds a polycarbonate polyurethane monomer to the main reaction monomer. Since the polyester polyol polyurethane will hydrolyze under high-temperature water vapor and the polyether polyol polyurethane has a structural strength problem, the polycarbonate polyurethane monomer used in the present invention has the advantages of both polyester and polyether, and the polycarbonate polyurethane monomer has good flexibility, relieves stress, improves interface adhesion, is resistant to hydrolysis, and has high mechanical strength, so that the water resistance and impact resistance of the ACF conductive adhesive are improved.

[0023] The present invention isolates the conductive particles from water and oxygen because the NCO residue of the polycarbonate polyurethane monomer is lower, and NCO is easier to combine with water and oxygen. The lower NCO residue can effectively inhibit electrochemical corrosion of the ACF conductive adhesive. DETAILED DESCRIPTION

[0024] The method of the present invention is described below by specific examples, but the present invention is not limited thereto. The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0025] Example 1

[0026] A water-absorption resistant ACF conductive tape comprises a release film layer and an adhesive film layer coated on the upper surface of the release layer. The thickness of the adhesive film layer is 35 μm. The adhesive film layer comprises the following components by weight: 32 parts of film-forming resin, 38.8 parts of main reaction monomer, 7 parts of rubber, 5 parts of conductive particles, 10.5 parts of filler, 4 parts of auxiliary agent, 0.3 parts of inhibitor, and 2.4 parts of initiator.

[0027] in:

[0028] The main reaction monomers include 11.85 parts of commercial polycarbonate polyurethane monomers, 11.85 parts of self-synthesized polycarbonate polyurethane monomers, 7.90 parts of isocyanuric acid acrylate monomers, 1.60 parts of 4-hydroxybutyl acrylate monomers, 2.40 parts of polyester acrylate monomers, and 3.20 parts of 2-[(2-propylene-1-yloxy)methyl]-2-methyl acrylate monomers, which are composed of a total of six monomers.

[0029] Self-synthesized polycarbonate polyurethane monomers are synthesized by the following steps:

[0030] Accurately weigh 70.0 g of polycarbonate polyol in a reactor, cover the reactor lid, install a jacketed reactor, and ensure that the reactor is airtight; raise the temperature in the reactor to 120±1°C, stir at a speed of 120±5RPM, and evacuate for 30±1min; cool the materials in the reactor to 90°C, pass N2, add 0.1 g of dibutyltin dilaurate as a catalyst, stir at a speed of 120±5RPM, and stir for 15±1min; add 30.0 g of diisocyanate, stir for 6h±10min; add hydroxyl acrylate monomer, stir for 6h±10min, stop stirring after the reaction, and cool to room temperature to obtain a polycarbonate polyurethane monomer.

[0031] The film-forming resin is phenoxy resin, and the rubber is terminal hydroxyl nitrile rubber. The filler is 10 parts of fumed silica and 0.5 parts of titanium dioxide. The auxiliary agent is 0.8 parts of silane coupling agent and 3.2 parts of 2-(methyl)acryloyloxyethyl phosphate. The inhibitor is 0.25 parts of bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and 0.05 parts of tert-butyl catechol. The initiator is 2.4 parts of 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate. The conductive particles are spherical silicon nickel-plated, and the spherical particle size is 3-5um.

[0032] The preparation process of the ACF conductive tape comprises the following steps:

[0033] (1) The main reaction and the filler are mixed uniformly by a three-roll mill to prepare a pre-mixed material A;

[0034] (2) Pre-mixing material A, film-forming resin and rubber at 60-80° C. and a rotation speed of 150 r / min to prepare pre-mixing material B;

[0035] (3) Add conductive particles, additives, inhibitors and initiators to the pre-prepared material B, stir evenly to obtain a film material, heat the film material at 60° C. with a coating machine, coat it on a release paper to form a film layer, and cool and dry to obtain an ACF conductive tape.

[0036] Comparative Example 1

[0037] Comparative Example 1 discloses an ACF conductive tape, the formulation and preparation process of which are the same as those of Example 1, except that the conductive particles therein are nickel powder.

[0038] Comparative Example 2

[0039] Comparative Example 2 discloses an ACF conductive tape, wherein: the main reaction monomers include 23.70 parts of commercial polycarbonate polyurethane monomer, 7.90 parts of isocyanuric acid acrylic acid monomer, 1.60 parts of 4-hydroxybutyl acrylate monomer, 2.40 parts of polyester acrylate monomer, and 3.20 parts of 2-[(2-propylene-1-yloxy)methyl]-2-methyl acrylate monomer, which is composed of six monomers in total. The other components and preparation process of the ACF conductive tape are the same as those of Example 1.

[0040] Comparative Example 3

[0041] Comparative Example 3 discloses an ACF conductive tape, wherein: the main reaction monomers include 23.70 parts of self-synthesized polycarbonate polyurethane monomer, 7.90 parts of isocyanuric acid acrylic acid monomer, 1.60 parts of 4-hydroxybutyl acrylate monomer, 2.40 parts of polyester acrylate monomer, and 3.20 parts of 2-[(2-propylene-1-yloxy)methyl]-2-methyl acrylate monomer, which is composed of a total of six monomers. The other components and preparation process of the ACF conductive tape are the same as those of Example 1.

[0042] Comparative Example 4

[0043] Comparative Example 4 discloses an ACF conductive tape, wherein: the main reaction monomers include 7.90 parts of commercial polycarbonate polyurethane monomers, 15.80 parts of self-synthesized polycarbonate polyurethane monomers, 7.90 parts of isocyanuric acid acrylate monomers, 1.60 parts of 4-hydroxybutyl acrylate monomers, 2.40 parts of polyester acrylate monomers, and 3.20 parts of 2-[(2-propylene-1-yloxy)methyl]-2-methyl acrylate monomers, which are composed of a total of six monomers. The other components and preparation process of the ACF conductive tape are the same as those of Example 1.

[0044] The ACF conductive tapes (initial) prepared in Example 1 and Comparative Examples 1-4 were subjected to tension and impedance tests respectively, and the test conditions were 140°C, 160°C, 180°C, 6S, 4Mpa, and the results were as follows:

[0045]

[0046] The ACF conductive tapes prepared in Example 1 and Comparative Examples 1-4 were subjected to HAST tests respectively. The HAST test was conducted under high temperature and high humidity (temperature 110°C, humidity 85%, pressure 1.2 Kg / cm 3 ) Stability test of samples. The results are as follows:

[0047]

[0048] The test data show that the tensile force and impedance of Example 1 are excellent after the initial and stability tests.

[0049] The above embodiments have provided a detailed introduction to the technical solutions provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A water-resistant ACF conductive tape. It is characterized in that It comprises a release film layer and an adhesive film layer coated on the upper surface of the release layer; the adhesive film layer comprises the following components by weight: 30-35 parts of film-forming resin, 35-40 parts of main reaction monomer, 5-8 parts of rubber, 3-5 parts of conductive particles, 9-11 parts of filler, 3-6 parts of auxiliary agent, 0.1-0.5 parts of inhibitor, and 1.0-3.5 parts of initiator.

2. The ACF conductive tape according to claim 1, It is characterized in that The adhesive film layer includes the following components by weight: 32 parts of film-forming resin, 38.8 parts of main reaction monomers, 7 parts of rubber, 5 parts of conductive particles, 10.5 parts of fillers, 4 parts of additives, 0.3 parts of inhibitors, and 2.4 parts of initiators.

3. The anti-water absorption ACF conductive tape according to claim 1, It is characterized in that The thickness of the adhesive film layer is 20-50 um.

4. The ACF conductive tape according to claim 1, It is characterized in that The main reaction monomers are a mixture of six monomers: commercial polycarbonate polyurethane monomers, self-synthesized polycarbonate polyurethane monomers, isocyanuric acid acrylate monomers, 4-hydroxybutyl acrylate monomers, polyester acrylate monomers, and 2-[(2-propylene-1-yloxy)methyl]-2-methyl acrylate monomers.

5. The ACF conductive tape according to claim 4, It is characterized in that The self-synthesized polycarbonate polyurethane monomer is synthesized by the following steps: Accurately weigh 70.0 g of polycarbonate polyol in a reactor, cover the reactor lid, install a jacketed reactor, and ensure that the reactor is airtight; raise the temperature in the reactor to 120±1°C, stir at a speed of 120±5RPM, and evacuate for 30±1min; cool the materials in the reactor to 90°C, pass N2, add 0.1 g of dibutyltin dilaurate as a catalyst, stir at a speed of 120±5RPM, and stir for 15±1min; add 30.0 g of diisocyanate, stir for 6h±10min; add hydroxyl acrylate monomer, stir for 6h±10min, stop stirring after the reaction, and cool to room temperature to obtain a polycarbonate polyurethane monomer.

6. The anti-water absorption ACF conductive tape according to claim 1, It is characterized in that The film-forming resin is a phenoxy resin; the rubber is a terminal hydroxyl nitrile rubber; the filler is fumed silica and titanium dioxide; the auxiliary agent is a silane coupling agent and 2-(methyl)acryloyloxyethyl phosphate; the inhibitor is bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and p-tert-butylcatechol; and the initiator is 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate.

7. The anti-water absorption ACF conductive tape according to claim 1, It is characterized in that The conductive particles are any one of silicon-plated nickel and nickel powder.

8. The ACF conductive tape according to claim 7, It is characterized in that The particle size of the conductive particles is 3-5 um.

9. The ACF conductive tape according to claim 7, It is characterized in that The conductive particles are in the form of spherical particles.

10. A process for preparing a water-absorption resistant ACF conductive tape according to any one of claims 1 to 9, It is characterized in that The following steps are involved: (1) The main reaction monomer and the filler are mixed uniformly by a three-roll mill to prepare a pre-mixed material A; (2) Pre-mixing material A, film-forming resin and rubber at 60-80° C. and a rotation speed of 150 r / min to prepare pre-mixing material B; (3) Add conductive particles, additives, inhibitors and initiators to the pre-prepared material B, stir evenly to obtain a film material, heat the film material and apply it on the release paper to form a film layer through a coating machine, and cool and dry to obtain an ACF conductive tape.

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