UV-curable composition and high-impact adhesive tape prepared from same

Abstract

The invention relates to the technical field of structural adhesives, and discloses a UV-curable composition and a high-impact adhesive tape prepared from the same. The high-impact-resistance adhesive tape comprises a UV-curable composition and a middle base material with micro-nano holes, the UV-curable composition comprises a methacrylic acid polymer, flexible aliphatic chain modified epoxy resin, a photo-acid generator and a photosensitizer; the flexible aliphatic chain modified epoxy resin is prepared from epoxy resin and aliphatic dibasic acid in a molar ratio of 2: 1 through a bulk melting reaction; the middle base material with the micro-nano holes is a porous membrane material with the thickness smaller than 150 microns and the porosity larger than 50%. According to the invention, the UV-curable composition is compounded with the porous membrane material to obtain the high-impact-resistance adhesive tape, the adhesive tape is used in a room-temperature process, has excellent structural strength and impact resistance, has PC dynamic shear strength of more than 3 MPa and PC drop hammer impact energy of more than 0.5 J, and can replace a frame adhesive.

Description

Technical Field

[0001] The present invention relates to the technical field of structural adhesives, and specifically to a UV-curable composition and a high-impact-resistant tape prepared therefrom. Background Art

[0002] For the back frame bonding of consumer electronics, the impact resistance of the material is emphasized. The previously applied solutions, namely glue bonding and foam PSA bonding, both have excellent impact resistance. However, although the glue bonding has high ultimate strength, its initial strength builds slowly, making it unable to quickly fix components and affecting the assembly efficiency of the production line. On the other hand, foam PSA can be die-cut and is easy to position, but the tape has a low modulus and relatively insufficient creep resistance. Therefore, how to combine the performance advantages of both, and develop a tape that can be processed at room temperature, can be die-cut and is easy to position, has a relatively high modulus, good creep resistance, high impact resistance and high bonding strength has become an increasingly important new topic in the field of consumer electronics in recent years.

[0003] Existing tapes with high modulus and high bonding performance include two types: 1. Thermally curable film; 2. UV-curable film. Restricted by the existing resin system, the processing temperature of thermally curable film is generally >90°C. Some structural components in the field of consumer electronics are often sensitive to the assembly temperature, which limits the application of thermally curable film in this field. Therefore, UV-curable film will be an ideal potential application solution to replace the existing frame adhesives. Through the performance evaluation of existing UV-curable films, the UV-cured film temporarily cannot match the frame adhesive application. Due to its relatively high modulus and strong rigidity after curing, the cured UV film generally has poor impact resistance, and a certain solution is needed to improve the impact resistance of the film.

[0004] Common solutions to improve impact resistance are to increase the rubber elasticity or the microphase interface of the material, so that when the material is impacted, the impact energy is dissipated through energy conversion, without impacting the material itself and causing damage to the main structure. However, toughening solutions such as rubber will introduce opaque components to the system, which is not suitable for the UV-curing system.

[0005] Therefore, it is of great significance to develop a UV-curable back frame bonding tape with high impact resistance. Summary of the Invention

[0006] The present invention provides a UV-curable composition and a high-impact-resistant tape prepared therefrom. A UV-curable composition with flexible chain segments is compounded with a porous membrane material having micro-nano pores, and the impact resistance of the UV-curable film is further improved through the micro-nano structures arranged in a dispersed manner. The present invention provides the following technical solutions:

[0007] A UV-curable composition, comprising a methacrylic polymer, a flexible aliphatic chain-modified epoxy resin, a photoacid generator, and a photosensitizer; the flexible aliphatic chain-modified epoxy resin is prepared by a bulk melting reaction of an epoxy resin and an aliphatic dibasic acid in a molar ratio of 2:1.

[0008] The composition comprises the following components: by mass, 100 - 125 parts of a methacrylic polymer, 10 - 200 parts of a flexible aliphatic chain-modified epoxy resin, 0.5 - 30 parts of a photoacid generator, and 0.15 - 15 parts of a photosensitizer;

[0009] Preferably, the UV-curable composition comprises the following components: by mass, 100 - 125 parts of a methacrylic polymer, 10 - 100 parts of a flexible aliphatic chain-modified epoxy resin, 0.5 - 20 parts of a photoacid generator, and 0.15 - 10 parts of a photosensitizer.

[0010] The flexible aliphatic chain-modified epoxy resin is prepared as follows: melt the epoxy resin at 100°C - 150°C, add an aliphatic dibasic acid with a molar amount half of that of the epoxy resin, add the catalyst triphenylphosphine, and maintain the temperature for reaction for 3 - 5 h to obtain the flexible aliphatic chain-modified epoxy resin;

[0011] Preferably, the epoxy resin is an epoxy resin having more than 2 epoxy groups per molecule on average, preferably an epoxy resin with an epoxy value of 0.1 - 1.0, more preferably an epoxy resin with an epoxy value of 0.2 - 0.6.

[0012] The aliphatic dibasic acid is a long carbon chain (C6 - C18) dibasic acid or one or more of 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid.

[0013] The photoacid generator is any one or more of diaryliodonium salts, triarylsulfonium salts, aryl diazonium salts, etc.;

[0014] Preferably, the photosensitizer is any one or more of polycyclic quinones, azo compounds, organic sulfides, halides, etc.

[0015] The acid value of the methacrylic polymer is 5.6 - 56 mgKOH / g; preferably, the epoxy value of the methacrylic polymer is 0.01 - 0.1.

[0016] The methacrylic polymer comprises the following components: 70 - 100 parts by mass of non-functional methacrylic monomers, 0 - 15 parts of methacryloyl monomers containing polar functional groups, 0.5 - 5 parts of functional methacryloyl monomers, 1.5 - 10 parts of methacryloyl monomers containing epoxy groups, 0.2 part of initiator, and 150 parts of solvent; preferably, the solvent is ethyl acetate.

[0017] A preparation method of a UV-curable high-impact-resistant tape, characterized by comprising the following steps:

[0018] S1, Preparation of a flexible aliphatic chain-modified epoxy resin

[0019] Melt the epoxy resin at 100°C - 150°C, add an aliphatic dibasic acid, and after adding the catalyst triphenylphosphine, maintain the temperature for reaction for 3 - 5 h to obtain a flexible aliphatic chain-modified epoxy resin;

[0020] S2, Preparation of a methacrylic polymer

[0021] Mix the non-functional methacrylic monomers, methacryloyl monomers containing polar functional groups, functional methacryloyl monomers, methacryloyl monomers containing epoxy groups, initiator, and solvent in a glass bottle, introduce nitrogen for two minutes to remove oxygen and seal it, and place the reaction bottle in a polymerization device at 60 - 80°C for polymerization reaction for 8 - 10 h to prepare a methacrylic polymer with a viscosity of 1000 - 10000 cp;

[0022] S3, Preparation of a UV-curable composition

[0023] Mix the methacrylic polymer, flexible aliphatic chain-modified epoxy resin, photoacid generator, and photosensitizer evenly to obtain a UV-curable composition;

[0024] S4, Preparation of a UV-curable high-impact-resistant tape

[0025] Coat the UV-curable composition on a release film, dry it to obtain a dry adhesive film with a certain thickness, coat the UV-curable composition on another release film, dry it to obtain a dry adhesive film with a certain thickness, and tightly laminate the above two dried adhesive films on both sides of a porous membrane material with micro-nano pores to obtain a tape covered with release films on both sides.

[0026] A UV-curable high-impact-resistant tape, comprising the above-mentioned UV-curable composition and a porous membrane material with micro-nano pores.

[0027] Preferably, the adhesive thickness of the UV-curable high-impact-resistant tape is 100 - 500 um.

[0028] Preferably, the porous membrane material with micro-nano pores is a membrane material with a thickness < 150 μm and a porosity > 50%.

[0029] Preferably, the porous membrane material with micro-nano pores is one of polyester-based, polyamide-based non-woven fabric, and polyamide-based plain fabric.

[0030] A method for using a UV-curable high-impact-resistant tape. After the tape is attached to the first adherend, it is irradiated with a 365 nm LED ultraviolet light source, and the irradiation energy is 2 J / cm 2 - 8 J / cm 2 , then the second adherend is pressed onto the other side of the tape. The pressing conditions are 0.3 - 1.0 MPa, 25 - 80 °C, 5 - 120 s, and it is left to cure at room temperature for more than 24 h.

[0031] Beneficial effects:

[0032] (1) In the present invention, a flexible aliphatic chain-modified epoxy resin is designed and synthesized. It has good compatibility and bonding with the epoxy-modified acrylic resin, and the epoxy resin structure has an aliphatic flexible chain segment, which can improve the flexibility of the UV-curable composition after curing.

[0033] (2) The present invention provides a UV-curable composition. This composition contains curable components, a methacrylic polymer and a flexible aliphatic chain-modified epoxy resin. The methacrylic polymer contains carboxyl, anhydride groups, and epoxy groups. The flexible aliphatic chain-modified epoxy resin contains two epoxy functional groups. When activated by UV cations, the epoxy groups of the methacrylic polymer and the epoxy groups of the flexible aliphatic chain-modified epoxy resin can both be activated by UV cations to generate strong protonic acids. The generated strong protonic acids catalyze the cross-linking reaction, and the acidic groups such as carboxyl and anhydride present in the system can promote the forward progress of this reaction, making the structural adhesive film have a relatively uniform high cross-linking density, and having high structural strength and good adhesiveness after the reaction.

[0034] (3) The present invention provides a UV-curable high-impact-resistant tape. This tape composes the UV-curable composition with a porous membrane material having micro-nano pores. The UV-curable composition contains flexible chain segments, which improve the flexibility of the material. Composing it with the porous membrane material having micro-nano pores, a composite high-performance material with micro-nano size reinforcement is obtained. While enhancing the adhesive strength of the tape, the dispersed micro-nano structure improves the dissipation of energy at the micro-nano interface when the material is impacted, improving the impact resistance of the tape. Further, the porous membrane material has good ultraviolet and visible light penetrability, does not affect the UV activation of the tape, and provides good die-cutting performance for thick tapes.

[0035] (4) The present invention provides a UV-curable high-impact tape, which has mild use process conditions and can be processed at room temperature, avoiding the damage to some temperature-sensitive materials in electronic devices under high-temperature conditions. Detailed implementation manners

[0036] 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.

[0037] In the following embodiments, the raw materials used are shown in the following table:

[0038] Name Description Manufacturer ITX Photosensitizer, 2-Isopropylthioxanthone TC1 H2A Adipic Acid Maclean CHDA 1,4-Cyclohexanedicarboxylic Acid Maclean EPON 828 Liquid Epoxy Resin Derived from Bisphenol A, Average Epoxy Equivalent: 188.5 Hexion TPP Triphenylphosphine Maclean MA Non-functional Methacrylic Monomer: Methyl Acrylate Huayi BA Non-functional Methacrylic Monomer: Butyl Acrylate Huayi 2-HEA (Meth)acryloyl Monomer Containing Polar Functional Group: 2-Hydroxyethyl Acrylate Bafos AA Functional (Meth)acryloyl Monomer: Acrylic Acid Bafos GMA (Meth)acryloyl Monomer Containing Epoxy Group: Glycidyl Methacrylate Maclean EA Ethyl Acetate Dow AIBN Azobisisobutyronitrile Initiator TCl Triaryl Sulfonium Hexafluoroantimonate Photoacid Generator, Triaryl Sulfonium Hexafluoroantimonate Jiangsu Taitel P50 50um PET (Porosity < 50%, Visible Light Transmittance > 80%) Dongcai P50P 50um PET Porous Membrane (Porosity > 50%, Visible Light Transmittance > 80%) Self-made PWF50-200 50um Plain Weave Fabric (200 Mesh) (Porosity > 50%, Visible Light Transmittance > 80%) Changtai Packaging PWF50-800 50um Plain Weave Fabric (Porosity < 50%, Visible Light Transmittance < 80%) Changtai Packaging

[0039] The preparation of flexible aliphatic chain-modified epoxy resin includes the following 3 synthesis examples:

[0040] Synthesis example 1: 2 mol of EPON 828 and 1 mol of H2A were mixed at 100 °C, 0.02 mol of triphenylphosphine was added, and the reaction was carried out at a constant temperature for 5 h to obtain flexible aliphatic chain-modified epoxy resin 1.

[0041] Synthesis example 2: 2 mol of EPON 828 and 1 mol of CHDA were mixed at 130 °C, 0.02 mol of triphenylphosphine was added, and the reaction was carried out at a constant temperature for 4 h to obtain flexible aliphatic chain-modified epoxy resin 2.

[0042] Synthesis example 3: 2 mol of EPON 828 and 1 mol of CHDA were mixed at 150 °C, 0.02 mol of triphenylphosphine was added, and the reaction was carried out at a constant temperature for 3 h to obtain flexible aliphatic chain-modified epoxy resin 3.

[0043] The preparation of methacrylic polymers includes the following 5 synthesis examples, by mass:

[0044] Synthesis example 1: 40 parts of MA, 30 parts of BA, 10 parts of GMA, 5 parts of AA, 15 parts of 2-HEA, 0.2 part of AIBN, and 150 parts of EA were mixed in a glass bottle, nitrogen was introduced for two minutes to remove oxygen and sealed, and the reaction bottle was placed in a polymerization device at 60 °C for polymerization reaction for 8 h to prepare a methacrylic polymer with a solid content of 40% and a viscosity of 5000 cp.

[0045] Synthesis Example 2: 40 parts of MA, 50 parts of BA, 1.5 parts of GMA, 2.5 parts of AA, 6 parts of 2-HEA, 0.2 part of AIBN, and 150 parts of EA were mixed in a glass bottle. Nitrogen was introduced for two minutes to remove oxygen and then sealed. The reaction bottle was placed in a polymerization apparatus and polymerized at 80 °C for 10 h to prepare a methacrylic polymer with a solid content of 40% and a viscosity of 4900 cp.

[0046] Synthesis Example 3: 48 parts of MA, 50 parts of BA, 1.5 parts of GMA, 0.5 part of AA, 0.2 part of AIBN, and 150 parts of EA were mixed in a glass bottle. Nitrogen was introduced for two minutes to remove oxygen and then sealed. The reaction bottle was placed in a polymerization apparatus and polymerized at 60 °C for 10 h to prepare a methacrylic polymer with a solid content of 40% and a viscosity of 6600 cp.

[0047] Synthesis Example 4: 50 parts of MA, 30 parts of BA, 10 parts of GMA, 5 parts of AA, 5 parts of 2-HEA, 0.2 part of AIBN, and 150 parts of EA were mixed in a glass bottle. Nitrogen was introduced for two minutes to remove oxygen and then sealed. The reaction bottle was placed in a polymerization apparatus and polymerized at 80 °C for 9 h to prepare a methacrylic polymer with a solid content of 40% and a viscosity of 7700 cp.

[0048] Synthesis Example 5: 47 parts of MA, 30 parts of BA, 6 parts of GMA, 2 parts of AA, 15 parts of 2-HEA, 0.2 part of AIBN, and 150 parts of EA were mixed in a glass bottle. Nitrogen was introduced for two minutes to remove oxygen and then sealed. The reaction bottle was placed in a polymerization apparatus and polymerized at 70 °C for 9 h to prepare a methacrylic polymer with a solid content of 40% and a viscosity of 6200 cp.

[0049] Preparation of UV-curable high-impact tape, Examples 1-5, Comparative Examples 1-5, by mass parts:

[0050] Example 1: 100 parts of the methacrylic polymer (40% solid content) from Synthesis Example 1, 10 parts of flexible aliphatic chain-modified epoxy resin 1, 0.5 part of triaryl sulfonium hexafluoroantimonate, and 0.15 part of ITX were mixed evenly to obtain Composition 1;

[0051] Composition 1 was coated on a release film with a thickness of 50 μm and dried at 110 °C for 8 min, and the dry film thickness was 115 μm. Composition 1 was coated on a release film with a thickness of 30 μm and dried at 110 °C for 8 min, and the dry film thickness was 115 μm. The above two dried adhesive films were respectively tightly laminated on both sides of a 50 μm PET porous film (P50P) to obtain an adhesive film (total thickness excluding the release film was about 250 μm).

[0052] Example 2: 100 parts of the methacrylic polymer of Synthesis Example 2 (40% solid content), 60 parts of the flexible aliphatic chain-modified epoxy resin 2, 5 parts of triaryl sulfonium hexafluoroantimonate, and 3 parts of ITX were mixed evenly to obtain Composition 2;

[0053] Composition 2 was coated on a release film with a thickness of 50 μm and dried at 110°C for 8 minutes, and the dry film thickness was 115 μm. Composition 2 was coated on a release film with a thickness of 30 μm and dried at 110°C for 8 minutes, and the dry film thickness was 115 μm. The above two dried adhesive films were respectively tightly laminated on both sides of a 50 μm PET porous film (P50P) to obtain an adhesive film (total thickness excluding the release film was about 250 μm).

[0054] Example 3: 100 parts of the methacrylic polymer of Synthesis Example 3 (40% solid content), 30 parts of the flexible aliphatic chain-modified epoxy resin 3, 4 parts of triaryl sulfonium hexafluoroantimonate, and 2 parts of ITX were mixed evenly to obtain Composition 3;

[0055] Composition 3 was coated on a release film with a thickness of 50 μm and dried at 110°C for 8 minutes, and the dry film thickness was 115 μm. Composition 3 was coated on a release film with a thickness of 30 μm and dried at 110°C for 8 minutes, and the dry film thickness was 115 μm. The above two dried adhesive films were respectively tightly laminated on both sides of a 200-mesh 50 μm plain woven fabric (PWF50-200) to obtain an adhesive film (total thickness excluding the release film was about 250 μm).

[0056] Example 4: 100 parts of the methacrylic polymer of Synthesis Example 4 (40% solid content), 100 parts of the flexible aliphatic chain-modified epoxy resin 1, 20 parts of triaryl sulfonium hexafluoroantimonate, and 10 parts of ITX were mixed evenly to obtain Composition 4;

[0057] Composition 4 was coated on a release film with a thickness of 50 μm and dried at 110°C for 8 minutes, and the dry film thickness was 115 μm. Composition 4 was coated on a release film with a thickness of 30 μm and dried at 110°C for 8 minutes, and the dry film thickness was 115 μm. The above two dried adhesive films were respectively tightly laminated on both sides of a 200-mesh 50 μm plain woven fabric (PWF50-200) to obtain an adhesive film (total thickness excluding the release film was about 250 μm).

[0058] Example 5: 100 parts of the methacrylic polymer of Synthesis Example 5 (40% solid content), 80 parts of the flexible aliphatic chain-modified epoxy resin 2, 10 parts of triaryl sulfonium hexafluoroantimonate, and 5 parts of ITX were mixed evenly to obtain Composition 5;

[0059] Coat Composition 5 on a release film with a thickness of 50 μm, dry at 110°C for 8 min, and the dry film thickness is 115 μm. Coat Composition 5 on a release film with a thickness of 30 μm, dry at 110°C for 8 min, and the dry film thickness is 115 μm. Press the two dried adhesive films tightly on both sides of a 50 μm PET porous film (P50P) respectively to obtain an adhesive film (total thickness excluding the release film is about 250 μm).

[0060] Comparative Example 1: Mix 100 parts of the methacrylic polymer of Synthesis Example 3 (40% solid content), 4 parts of triaryl sulfonium hexafluoroantimonate, and 2 parts of ITX evenly to obtain Composition 6;

[0061] Coat Composition 6 on a release film with a thickness of 50 μm, dry at 110°C for 8 min, and the dry film thickness is 115 μm. Coat Composition 6 on a release film with a thickness of 30 μm, dry at 110°C for 8 min, and the dry film thickness is 115 μm. Press the two dried adhesive films tightly on both sides of a 200-mesh 50 μm plain woven fabric (PWF50-200) respectively to obtain an adhesive film (total thickness excluding the release film is about 250 μm).

[0062] Comparative Example 2: Mix 100 parts of the methacrylic polymer of Synthesis Example 3 (40% solid content), 30 parts of EPON 828, 4 parts of triaryl sulfonium hexafluoroantimonate, and 2 parts of ITX evenly to obtain Composition 7;

[0063] Coat Composition 7 on a release film with a thickness of 50 μm, dry at 110°C for 8 min, and the dry film thickness is 115 μm. Coat Composition 7 on a release film with a thickness of 30 μm, dry at 110°C for 8 min, and the dry film thickness is 115 μm. Press the two dried adhesive films tightly on both sides of a 200-mesh 50 μm plain woven fabric (PWF50-200) respectively to obtain an adhesive film (total thickness excluding the release film is about 250 μm).

[0064] Comparative Example 3: Mix 100 parts of the methacrylic polymer of Synthesis Example 3 (40% solid content), 30 parts of a flexible aliphatic chain-modified epoxy resin 3, 4 parts of triaryl sulfonium hexafluoroantimonate, and 2 parts of ITX evenly to obtain Composition 8;

[0065] Coat Composition 8 on a release film with a thickness of 50 μm, dry at 110°C for 8 min, and the dry film thickness is 115 μm. Coat Composition 8 on a release film with a thickness of 30 μm, dry at 110°C for 8 min, and the dry film thickness is 115 μm. Press the two dried adhesive films tightly on both sides of a 50 μm PET (P50) respectively to obtain an adhesive film (total thickness excluding the release film is about 250 μm).

[0066] Comparative Example 4: 100 parts of the methacrylic polymer of Synthesis Example 3 (40% solids content), 30 parts of the flexible aliphatic chain-modified epoxy resin 3, and 2 parts of ITX were mixed evenly to obtain Composition 9;

[0067] Composition 9 was coated on a release film with a thickness of 50 μm and dried at 110°C for 8 min. The dry film thickness was 115 μm. Composition 9 was coated on a release film with a thickness of 30 μm and dried at 110°C for 8 min. The dry film thickness was 115 μm. The above two dried adhesive films were respectively tightly laminated on both sides of a 200-mesh 50-μm plain woven fabric (PWF50-200) to obtain an adhesive film (total thickness excluding the release film was about 250 μm).

[0068] Comparative Example 5: 100 parts of the methacrylic polymer of Synthesis Example 3 (40% solids content), 30 parts of the flexible aliphatic chain-modified epoxy resin 3, 4 parts of triaryl sulfonium hexafluoroantimonate, and 2 parts of ITX were mixed evenly to obtain Composition 10;

[0069] Composition 10 was coated on a release film with a thickness of 50 μm and dried at 110°C for 8 min. The dry film thickness was 115 μm. Composition 10 was coated on a release film with a thickness of 30 μm and dried at 110°C for 8 min. The dry film thickness was 115 μm. The above two dried adhesive films were respectively tightly laminated on both sides of an 800-mesh 50-μm plain woven fabric (PWF50-800) to obtain an adhesive film (total thickness excluding the release film was about 250 μm).

[0070] Test: The tapes prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were subjected to performance tests, and the obtained data are shown below:

[0071] The initial dynamic shear performance was tested as follows:

[0072] Before the test, the PC board (5 inches * 1 inch) was wiped three times with ethanol. The adhesive film sample with release films on both sides was cut into 1 inch * 1 inch, one side of the release film was peeled off and pasted on a PC board. The other side of the release film was peeled off, and another PC board was directly pasted on the other adhesive surface. The test sample was cured in a controlled environment chamber (23°C / 50% relative humidity) for 24 hours and then tested.

[0073] The dynamic shear force was tested using a tensile tester from Instron Corporation. The speed was 10.0 mm / min. Each test was repeated three times, and the average value was taken, with the unit of MPa.

[0074] The dynamic shear performance was tested as follows:

[0075] Wipe the PC board (5 inches * 1 inch) with ethanol three times before testing. Cut the film sample with release films on both sides into 1 inch * 1 inch, remove the release film on one side, and stick it on a PC board. Remove the release film on the other side and irradiate with UV (365nm LED lamp, UVA is about 4000mJ / cm 2 ), and stick another PC board on the other adhesive surface. Place the test sample in a controlled environment chamber (23°C / 50% relative humidity) for post-curing for 24 hours, and then conduct the test. Or place the prepared sample in an 80°C oven for accelerated curing for 1 hour. After taking it out of the oven, cool the test sample to room temperature in a controlled environment chamber (23°C / 50% relative humidity) before measuring.

[0076] The dynamic shear force is tested using a tensile tester from Instron Corporation. The speed is 10.0 mm / min. Each test is repeated three times, and the average value is taken, with the unit of MPa.

[0077] The impact performance test is as follows:

[0078] Wipe the PC board with ethanol three times before testing. Cut the film sample with release films on both sides into a square ring-shaped adhesive sample with an inner side length of 20.5 mm and an outer side length of 24.5 mm. Remove the release film on one side and stick it on a PC board (Frame, 40 mm * 40 mm, with a 20.5 mm * 20.5 mm square hole inside). Remove the release film on the other side and irradiate with UV (365nm LED lamp, UVA is about 4000mJ / cm 2 ), and stick another PC board (Window, 24.5 mm * 24.5 mm) on the other adhesive surface. Place the test sample in a controlled environment chamber (23°C / 50% relative humidity) for post-curing for 24 hours, and then conduct the test. Or place the prepared sample in an 80°C oven for accelerated curing for 1 hour. After taking it out of the oven, cool the test sample to room temperature in a controlled environment chamber (23°C / 50% relative humidity) before measuring.

[0079] The falling weight impact is tested using an impact tester from Instron Corporation. The weight of the falling weight is 15.125 kg, the falling height is 205 mm, the impact energy is 30.4 J, and the impact speed is 2.01 m / s. Each test is repeated three times, and the average value is taken, with the unit of J.

[0080] The test results are shown in the following table:

[0081] Initial Dynamic Shear MPa Dynamic Shear MPa after UV Energy at the End of Drop Hammer Impact J Example 1 0.26 4.01 0.56 Example 2 0.22 4.62 0.58 Example 3 0.25 3.76 0.71 Example 4 0.11 3.87 0.52 Example 5 0.17 4.76 0.54 Comparative Example 1 0.35 0.44 0.29 Comparative Example 2 0.23 3.53 0.39 Comparative Example 3 0.19 4.23 0.31 Comparative Example 4 0.26 0.35 0.19 Comparative Example 5 0.19 3.72 0.34

[0082] Conclusion: As can be seen from the data in the table, in Comparative Example 1, no epoxy resin was used, so the adhesive strength and impact resistance of the cured adhesive film were both poor. In Comparative Example 2, the epoxy resin modified with a flexible aliphatic chain was not used. Although the adhesive strength of the cured adhesive film was strong, the impact resistance was insufficient. The film materials used in Comparative Examples 3 and 5 did not meet the requirement of a porosity > 50%, so the impact resistance of the cured adhesive film was poor. In Comparative Example 4, no UV initiator was used in the adhesive film, so the adhesive film could not be cured by ultraviolet activation, which affected its adhesive performance and impact resistance. Examples 1 to 5 prepared according to the method provided by the present invention have good impact resistance and excellent adhesive performance.

[0083] The above are only alternative embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the content of the specification of the present invention under the inventive concept of the present invention, or directly or indirectly applied to other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A UV-curable composition, characterized in that: The UV-curable composition comprises a methacrylic polymer, a flexible fatty chain-modified epoxy resin, a photoacid generator, and a photosensitizer; the flexible fatty chain-modified epoxy resin is prepared by a bulk melting reaction of an epoxy resin and an aliphatic dibasic acid in a molar ratio of 2:

1.

2. A UV-curable composition according to claim 1, characterized in that: The composition comprises the following components: by weight, 100-125 parts of a methacrylic polymer, 10-200 parts of a flexible fatty chain-modified epoxy resin, 0.5-30 parts of a photoacid generator, and 0.15-15 parts of a photosensitizer; Preferably, the UV-curable composition comprises the following components: by mass, 100-125 parts of methacrylic polymer, 10-100 parts of flexible fatty chain-modified epoxy resin, 0.5-20 parts of photoacid generator, and 0.15-10 parts of photosensitizer.

3. A UV-curable composition according to claim 1, characterized in that: The flexible fatty chain modified epoxy resin is prepared as follows: the epoxy resin is melted at 100° C.-150° C., and an aliphatic dibasic acid is added in an amount of half that of the epoxy resin, and after adding a catalyst triphenylphosphine, the temperature is maintained for reaction for 3-5 hours to obtain the flexible fatty chain modified epoxy resin; Preferably, the epoxy resin is an epoxy resin having two or more epoxy groups in each molecule on average, preferably an epoxy resin having an epoxy value of 0.1-1.0, and more preferably an epoxy resin having an epoxy value of 0.2-0.

6. The aliphatic dicarboxylic acid is a long carbon chain (C6-C18) dicarboxylic acid or one or more of 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid.

4. A UV-curable composition according to claim 1, characterized in that: The photoacid generator is any one or more of diaryl iodonium salts, triaryl sulfonium salts, and aryl diazonium salts; Preferably, the photosensitizer is any one or more of condensed ring quinones, azo compounds, organic sulfides, and halides.

5. A UV-curable composition according to claim 1, characterized in that: The acid value of the methacrylic acid polymer is 5.6-56 mgKOH / g; Preferably, the epoxy value of the methacrylic polymer is 0.01-0.

1.

6. A UV-curable composition according to claim 1, characterized in that: The methacrylic polymer comprises the following components: by mass, 70-100 parts of non-functional methacrylic monomers, 0-15 parts of methacrylic monomers containing polar functional groups, 0.5-5 parts of functional methacrylic monomers, 1.5-10 parts of methacrylic monomers containing epoxy groups, 0.2 parts of initiators, and 150 parts of solvents.

7. A method for preparing a UV-curable high-impact tape, characterized in that: The following steps are involved: S1, Preparation of flexible fatty chain modified epoxy resin Melt the epoxy resin at 100-150°C, add aliphatic dibasic acid, add triphenylphosphine as a catalyst, and maintain the temperature for 3-5 hours to obtain a flexible aliphatic chain modified epoxy resin; S2, Preparation of methacrylic acid polymer A non-functional methacrylic acid monomer, a methacrylic acid monomer containing a polar functional group, a functional methacrylic acid monomer, a methacrylic acid monomer containing an epoxy group, an initiator, and a solvent are mixed in a glass bottle, nitrogen is introduced for two minutes to remove oxygen, and the bottle is sealed, and the reaction bottle is placed in a polymerization device at 60-80° C. for 8-10 hours to prepare a methacrylic acid polymer with a viscosity of 1000-10000cp; S3. Preparation of UV-curable composition The methacrylic acid polymer, the flexible fatty chain modified epoxy resin, the photoacid generator and the photosensitizer are uniformly mixed to obtain a UV curable composition; S4, Preparation of UV-curable high impact tape The UV-curable composition is coated on a release film and dried to obtain a dry adhesive film of a certain thickness. The UV-curable composition is coated on another release film and dried to obtain a dry adhesive film of a certain thickness. The above two parts of dried adhesive films are tightly pressed on both sides of a porous membrane material with micro-nano pores to obtain a tape with release films covered on both sides.

8. A UV-curable high-impact tape, characterized in that: The invention comprises the UV-curable composition according to any one of claims 1 to 6 and a porous membrane material having micro-nano pores.

9. The UV-curable high-impact adhesive tape according to claim 8, characterized in that: The thickness of the UV-curable high-impact tape is 100-500um; the porous membrane material with micro-nano pores is a membrane material with a thickness of less than 150um and a porosity of more than 50%; Preferably, the porous membrane material with micro-nano pores is one of polyester-based, polyamide-based non-woven fabric and polyamide-based plain woven fabric.

10. A method for using a UV-curable high-impact adhesive tape according to any one of claims 8 to 9, characterized in that: After the tape is attached to the first object, it is irradiated with a 365nm LED UV light source with an irradiation energy of 2J / cm 2 -8J / cm 2 Then press the second object to the other side of the tape under the conditions of 0.3-1.0MPa, 25-80℃, 5-120s, and leave it at room temperature for more than 24 hours.