High-heat-resistance and high-toughness epoxy resin optical film and preparation method thereof

Abstract

The invention discloses a high-heat-resistance and high-toughness epoxy resin optical film and a preparation method thereof.The optical film comprises a base material and a high-heat-resistance and high-toughness epoxy resin layer, and the resin layer comprises 40-60 parts of bisphenol A epoxy resin, 20-30 parts of alicyclic epoxy resin, 5-10 parts of nitrogen-sulfur heterocyclic propane and 1-5 parts of a core-shell particle toughening agent; the curing agent is prepared from the following components in parts by weight: 10-15 parts of epoxy resin, 5-12 parts of hydroxyl-terminated polysiloxane-polyurethane prepolymer, 10-15 parts of diamine curing agent, 1-10 parts of inorganic filler and 0.5-2 parts of silane coupling agent. According to the optical film, nitrogen-sulfur heterocyclic propane is introduced and matched with the core-shell particle toughening agent, the hydroxyl-terminated polysiloxane-polyurethane prepolymer and other substances, a high-refraction thioether-amine cross-linked network is formed, heat resistance is kept, and meanwhile toughness and optical performance are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin optical film technology, and in particular to a high heat-resistant and high-toughness epoxy resin optical film and its preparation method. Background Technology

[0002] Epoxy resin optical film refers to optical film made mainly of epoxy resin. Because epoxy resin contains a variety of polar groups and highly active epoxy groups, and especially because the cohesive strength of epoxy cured products is relatively high, it is suitable for use as an adhesive. However, when applied to optical film, its high cohesive strength results in optical film that is generally brittle and has poor impact resistance without toughening, making it unsuitable for touch screen protective film of electronic products.

[0003] In existing technologies, toughening agents are often added to take advantage of the high-temperature resistance of epoxy resin, but its toughness is still insufficient. In addition, its light transmittance, wear resistance and other properties do not meet the requirements of protective films for touch screens of electronic products. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, one of the objectives of this invention is to provide a high heat-resistant and high-toughness epoxy resin optical film to solve the above-mentioned problems of traditional technology. This invention introduces nitrogen-sulfur heterocyclic propane to form a high-refractive-index sulfide-amine crosslinking network, which significantly improves toughness and optical performance while maintaining heat resistance.

[0005] The second objective of this invention is to provide a method for preparing the above-mentioned high heat resistance and high toughness epoxy resin optical film.

[0006] One of the objectives of this invention is achieved through the following technical solution: A high heat-resistant and high-toughness epoxy resin optical film includes a substrate and a high heat-resistant and high-toughness epoxy resin layer coated on one side of the substrate. The high heat-resistant and high-toughness epoxy resin layer comprises the following components in parts by weight: 40-60 parts of bisphenol A type epoxy resin, 20-30 parts of alicyclic epoxy resin, 5-10 parts of nitrogen-sulfur heterocyclic propane, 1-5 parts of core-shell particle toughening agent, 5-12 parts of hydroxyl-terminated polysiloxane-polyurethane prepolymer, 10-15 parts of diamine curing agent, 1-10 parts of inorganic filler, and 0.5-2 parts of silane coupling agent.

[0007] In this invention, by introducing nitrogen-sulfur heterocyclic propane and combining it with core-shell particle toughening agents, hydroxyl-terminated polysiloxane-polyurethane prepolymers, and other substances, a high-refractive-index sulfide-amine crosslinking network is formed, which significantly improves toughness and optical properties while maintaining heat resistance.

[0008] Furthermore, the thiazocyclopropane is one or more of 2-methyl-N-p-toluenesulfonyl azicyclopropane, 2-ethyl-N-p-toluenesulfonyl azicyclopropane, and 2-butyl-N-p-toluenesulfonyl azicyclopropane.

[0009] Furthermore, the bisphenol A type epoxy resin is E-51, with an epoxy value of 0.51-0.54 and a viscosity (mPa·s) of 11000-14000 mPa·s at 25 ℃.

[0010] Furthermore, the alicyclic epoxy resin is 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate (2021P) and / or vinylcyclohexene dioxide (ERL-4221), wherein 2021P has an epoxy value of 131-143 and a viscosity (mPa·s) of 400–600 mPa·s at 25 °C. ERL-4221 has an epoxy value of 131 and a viscosity (mPa·s) of 350 mPa·s at 25 °C.

[0011] Furthermore, the core-shell particle toughening agent is one or more of the commercially available EXL-2691, CSP-PP, and MX125, with a particle size of 80-150nm.

[0012] Furthermore, the hydroxyl-terminated polysiloxane-polyurethane prepolymer is PDMS-PU-1000, with a hydroxyl value of 56–62 mgKOH / g and a viscosity (25 ℃, mPa·s) of 800–1200 mPa·s.

[0013] Furthermore, the diamine curing agent is one or more of 4,4′-DDS and 4,4′-MDA.

[0014] Furthermore, the inorganic filler is an Al2O3-SiO2 composite powder, with an Al2O3:SiO2 mass ratio of 1:(1-3), such as 1:1, 1:1.5, 1:2, 1:2.5, or 1:3.

[0015] Furthermore, the silane coupling agent is one or more of γ-methacryloxypropyltrimethoxysilane and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

[0016] Furthermore, the substrate is one of polyethylene terephthalate (PET), polycarbonate (PC), or polymethyl methacrylate (PMMA).

[0017] The second objective of this invention is achieved by the following technical solution: A method for preparing a high heat-resistant and high-toughness epoxy resin optical film includes the following preparation steps: S1: The substrate is ultrasonically cleaned and then dried for later use; S2: Stir nitrogen-sulfur heterocyclic propane and alicyclic epoxy resin under vacuum at 55-65℃ for 20-40 minutes to pre-dope nitrogen-sulfur heterocyclic propane and prevent premature ring opening, thus obtaining a pre-doped material. S3: In a planetary mixer, add bisphenol A type epoxy resin, pre-doped material, core-shell particle toughening agent, hydroxyl-terminated polysiloxane-polyurethane prepolymer, inorganic filler, silane coupling agent and diamine curing agent in sequence, mix evenly, sonicate at room temperature for 10-15 minutes, and degas under vacuum to obtain coating adhesive. S4: Apply the coating adhesive to the substrate using coating equipment to obtain the final product.

[0018] Furthermore, the coating equipment is a three-roll calender, and the control parameters of the coating equipment are: wet film thickness 8–12 μm, infrared preheating at 100℃-120℃ for 25–35 s, first-stage hot pressing curing at 150-170℃ for 15–25 min, and second-stage hot pressing curing at 180-190℃ for 8–15 min. The curing is carried out in stages, so that the front part is first sulfidated and crosslinked, and then the front part is cured to ensure that the system forms a complete network structure.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: The optical film of the present invention introduces nitrogen-sulfur heterocyclic propane and combines it with core-shell particle toughening agents, terminal hydroxyl polysiloxane-polyurethane prepolymers, etc., to form a high-refractive-index sulfide-amine crosslinking network, which significantly improves toughness and optical performance while maintaining heat resistance. Detailed Implementation

[0020] The present invention will now be further described in conjunction with specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0021] Unless otherwise specified, all materials used in the following embodiments were purchased externally. The substrates used in the following embodiments and comparative examples are polycarbonate (PC).

[0022] The nitrogen-thiohexacyclic propane is 2-methyl-N-p-toluenesulfonyl nitrogen-thiocyclic propane, purchased from Aladdin; The bisphenol A type epoxy resin was E-51, purchased from Hubei Xinhongli Chemical Co., Ltd. The alicyclic epoxy resin is 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, purchased from Zhongyao Biotechnology (Suzhou) Co., Ltd. The core-shell particle toughening agent was EXL-2691, purchased from Aladdin. The diamine curing agent was 4,4′-DDS, purchased from Guangzhou Yuanda New Materials Co., Ltd. The inorganic filler is an Al2O3-SiO2 composite powder. The Al2O3 was purchased from Hubei Zhenbo Chemical Co., Ltd., and the SiO2 was purchased from Hubei Xinhongli Chemical Co., Ltd. Both are nano-sized powders.

[0023] Examples and comparative examples are shown below.

[0024] Example 1 An optical film includes a substrate and a high heat-resistant and high-toughness epoxy resin layer, the high heat-resistant and high-toughness epoxy resin layer comprising the following components in parts by weight: 42 parts of bisphenol A type epoxy resin, 20 parts of alicyclic epoxy resin, 5 parts of nitrogen-sulfur heterocyclic propane, 2 parts of core-shell particle toughening agent, 10 parts of hydroxyl-terminated polysiloxane-polyurethane prepolymer, 10 parts of diamine curing agent, 3 parts of inorganic filler, and 1 part of silane coupling agent.

[0025] The inorganic filler is an Al2O3-SiO2 composite powder, with a mass ratio of Al2O3 to SiO2 of 1:1.

[0026] Example 2 An optical film includes a substrate and a high heat-resistant and high-toughness epoxy resin layer, the high heat-resistant and high-toughness epoxy resin layer comprising the following components in parts by weight: 42 parts of bisphenol A type epoxy resin, 20 parts of alicyclic epoxy resin, 10 parts of nitrogen-sulfur heterocyclic propane, 2 parts of core-shell particle toughening agent, 10 parts of hydroxyl-terminated polysiloxane-polyurethane prepolymer, 10 parts of diamine curing agent, 3 parts of inorganic filler, and 1 part of silane coupling agent.

[0027] The inorganic filler is an Al2O3-SiO2 composite powder, with a mass ratio of Al2O3 to SiO2 of 1:1.

[0028] Example 3 An optical film includes a substrate and a high heat-resistant and high-toughness epoxy resin layer, the high heat-resistant and high-toughness epoxy resin layer comprising the following components in parts by weight: 42 parts of bisphenol A type epoxy resin, 20 parts of alicyclic epoxy resin, 5 parts of nitrogen-sulfur heterocyclic propane, 2 parts of core-shell particle toughening agent, 10 parts of hydroxyl-terminated polysiloxane-polyurethane prepolymer, 10 parts of diamine curing agent, 3 parts of inorganic filler, and 1 part of silane coupling agent.

[0029] The inorganic filler is an Al2O3-SiO2 composite powder, with a mass ratio of Al2O3 to SiO2 of 1:3.

[0030] Example 4 An optical film includes a substrate and a high heat-resistant and high-toughness epoxy resin layer, the high heat-resistant and high-toughness epoxy resin layer comprising the following components in parts by weight: 42 parts of bisphenol A type epoxy resin, 20 parts of alicyclic epoxy resin, 5 parts of nitrogen-sulfur heterocyclic propane, 5 parts of core-shell particle toughening agent, 10 parts of hydroxyl-terminated polysiloxane-polyurethane prepolymer, 10 parts of diamine curing agent, 3 parts of inorganic filler, and 1 part of silane coupling agent.

[0031] The inorganic filler is an Al2O3-SiO2 composite powder, with a mass ratio of Al2O3 to SiO2 of 1:1.

[0032] In the above embodiments, the preparation steps are as follows: S1: The substrate is ultrasonically cleaned and then dried for later use; S2: Nitrogen-sulfur heterocyclic propane and alicyclic epoxy resin are stirred in a vacuum environment of 55-65℃ for 30 minutes to pre-dope the nitrogen-sulfur heterocyclic propane and prevent premature ring opening, thus obtaining a pre-doped material. S3: In a planetary mixer, add bisphenol A type epoxy resin, pre-doped material, core-shell particle toughening agent, hydroxyl-terminated polysiloxane-polyurethane prepolymer, inorganic filler, silane coupling agent and diamine curing agent in sequence, mix evenly, sonicate at room temperature for 10 minutes, and degas under vacuum to obtain coating adhesive. S4: Apply the coating adhesive to the substrate using coating equipment to obtain the final product.

[0033] The coating equipment is a three-roll calender. The control parameters of the coating equipment are: wet film thickness 10μm, infrared preheating at 100℃-120℃ for 30s, first-stage hot pressing curing at 150-170℃ for 18min, and second-stage hot pressing curing at 180-190℃ for 10min.

[0034] Comparative Example 1 Unlike Example 1, Comparative Example 1 does not contain nitrogen-thiocyclopropane; the other materials and preparation methods are the same as in Example 1.

[0035] Comparative Example 2 Unlike Example 1, Comparative Example 2 does not contain a core-shell particle toughening agent; the other materials and preparation methods are the same as in Example 1.

[0036] Comparative Example 3 Unlike Example 1, Comparative Example 3 does not contain inorganic fillers; however, the materials and preparation methods are the same as in Example 1.

[0037] Performance testing 1. The test methods are shown in Table 1 below: Table 1

[0038] 2. The test results are shown in Table 2 below: Table 2

[0039] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A high heat-resistant and high-toughness epoxy resin optical film, characterized in that, The product includes a substrate and a high-heat-resistant, high-toughness epoxy resin layer coated on one side of the substrate. The high-heat-resistant, high-toughness epoxy resin layer comprises the following components in parts by weight: 40-60 parts of bisphenol A type epoxy resin, 20-30 parts of alicyclic epoxy resin, 5-10 parts of nitrogen-sulfur heterocyclic propane, 1-5 parts of core-shell particle toughening agent, 5-12 parts of hydroxyl-terminated polysiloxane-polyurethane prepolymer, 10-15 parts of diamine curing agent, 1-10 parts of inorganic filler, and 0.5-2 parts of silane coupling agent.

2. The high heat-resistant and high-toughness epoxy resin optical film according to claim 1, characterized in that, The nitrothionyl propane is one or more of 2-methyl-N-p-toluenesulfonyl nitrothionyl propane, 2-ethyl-N-p-toluenesulfonyl nitrothionyl propane, and 2-butyl-N-p-toluenesulfonyl nitrothionyl propane.

3. The high heat-resistant and high-toughness epoxy resin optical film according to claim 1, characterized in that, The bisphenol A type epoxy resin is E-51, with an epoxy value of 0.51-0.54 and a viscosity of 11000-14000 mPa·s at 25 ℃.

4. The high heat-resistant and high-toughness epoxy resin optical film according to claim 1, characterized in that, The alicyclic epoxy resin is 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarbamate and / or vinyl cyclohexene dioxide.

5. The high heat-resistant and high-toughness epoxy resin optical film according to claim 4, characterized in that, The 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate has an epoxy value of 131-143 and a viscosity of 400–600 mPa·s at 25 °C, while the vinyl cyclohexene dioxide has an epoxy value of 131 and a viscosity of 350 mPa·s at 25 °C.

6. The high heat-resistant and high-toughness epoxy resin optical film according to claim 1, characterized in that, The core-shell particle toughening agent is one or more of EXL-2691, CSP-PP, and MX125.

7. The high heat-resistant and high-toughness epoxy resin optical film according to claim 6, characterized in that, The core-shell toughening agent has a particle size of 80-150 nm.

8. The high heat-resistant and high-toughness epoxy resin optical film according to claim 1, characterized in that, The diamine curing agent is one or more of 4,4′-DDS and 4,4′-MDA.

9. The high heat-resistant and high-toughness epoxy resin optical film according to claim 1, characterized in that, The inorganic filler is an Al2O3-SiO2 composite powder, with a mass ratio of Al2O3 to SiO2 of 1:(1-3).

10. A method for preparing a high heat-resistant and high-toughness epoxy resin optical film as described in any one of claims 1-9, characterized in that, The preparation steps include the following: S1: The substrate is ultrasonically cleaned and then dried for later use; S2: Stir nitrogen-sulfur heterocyclic propane and alicyclic epoxy resin under vacuum at 55-65℃ for 20-40 minutes to pre-dope nitrogen-sulfur heterocyclic propane and prevent premature ring opening, thus obtaining a pre-doped material. S3: In a planetary mixer, add bisphenol A type epoxy resin, pre-doped material, core-shell particle toughening agent, hydroxyl-terminated polysiloxane-polyurethane prepolymer, inorganic filler, silane coupling agent and diamine curing agent in sequence, mix evenly, sonicate at room temperature for 10-15 minutes, and degas under vacuum to obtain coating adhesive. S4: Apply the coating adhesive to the substrate using coating equipment to obtain the final product.

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