Construction of optical shielding bio-based epoxy resin with participation of tetrathiol curing agent

Abstract

The invention discloses a method for constructing optical shielding bio-based epoxy resin with participation of a tetra-thiol curing agent, the bio-based epoxy resin curing agent (EUGSFH) is derived from bio-based substances eugenol and thioacetic acid, and the molar ratio of an epoxy group of an epoxy monomer to a thiol group in the bio-based curing agent EUGSFH is 1: (1.0-1.5). And a catalyst DMAP (1 / 1000) is added, so that the adhesive is cured under relatively mild conditions. Uniformly mixing at 50-70 DEG C, curing at 100-140 DEG C, and preparing a sample. The optical shielding performance of the resin provided by the invention is derived from the base material, and the resin has excellent heat resistance and good mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, specifically to the construction of an optically shielding bio-based epoxy resin involving a tetrathiol curing agent. Background Technology

[0002] Epoxy resins, with their excellent mechanical strength and good chemical stability, have been widely used in many fields such as aerospace, coatings, electronic components, construction engineering, and medical materials. However, the current market for epoxy resin products is still dominated by petroleum-based bisphenol A type, and long-term exposure to these resins can easily lead to a series of health risks. At the same time, research on the optical shielding properties of these bulk chemicals is relatively scarce, and their production is highly dependent on non-renewable petrochemical resources. Therefore, developing bio-based epoxy resin materials with optical shielding properties has significant theoretical and practical value for improving the stability, durability, and safety of these materials.

[0003] Ultraviolet (UV) radiation can cause varying degrees of damage to various applications, including building materials and precision instruments. Prolonged exposure to UV radiation can significantly reduce the corrosion resistance of precision instruments. Among different UV wavelengths, long-wave UVA (320–400 nm) has extremely strong penetrating power, accounting for approximately 95% of the total UV flux reaching the Earth's surface. This band of radiation can not only penetrate glass barriers into indoor environments but also penetrate deep into the dermis of human skin, causing pigmentation, aging, and wrinkles. Medium-wave UVB (280–320 nm) has a high energy density and, besides being a key factor in causing acute sunburn, also adversely affects the performance of various materials. The optical stability of epoxy resin is one of the core properties determining its application potential, which is closely related to its widespread use in outdoor applications. Under the long-term effects of natural environments such as sun exposure and rain, external factors such as ultraviolet radiation and temperature fluctuations can easily cause epoxy resins to age, exhibiting phenomena such as yellowing, cracking, and decreased gloss, severely limiting their service life and performance. Therefore, the practical application scenarios of epoxy resins in outdoor fields largely depend on their anti-aging properties. In view of this, developing epoxy resin materials with excellent optical shielding effects is of great significance for expanding the application boundaries of epoxy resins and enhancing their practical value.

[0004] The main objective of this invention is to provide a bio-based UV-resistant epoxy resin film and its preparation method. This resin film has good UV blocking ability, with a transmittance of 0% for short-wave ultraviolet (UVC) and medium-wave ultraviolet (UVB), a transmittance of less than 45% for long-wave ultraviolet (UVA), and a blue light blocking rate between 50% and 90%. Simultaneously, this resin film exhibits good heat resistance and mechanical properties. Summary of the Invention

[0005] Purpose of the invention: The technical problem to be solved by the present invention is to provide an optical shielding bio-based epoxy resin film with the participation of a tetrathiol curing agent, which addresses the shortcomings of the prior art.

[0006] Another technical problem to be solved by the present invention is to provide a method for constructing an optically shielding bio-based epoxy resin film involving the above-mentioned tetrathiol curing agent.

[0007] The technical problem that this invention also aims to solve is to provide the application advantages of optical shielding bio-based epoxy resin films involving the above-mentioned tetrathiol curing agent.

[0008] To address the first technical problem mentioned above, this invention discloses an optically shielding bio-based epoxy resin film involving a tetrathiol curing agent, wherein the polymerization of structural units A and B or A and C constitutes a novel binary polymer. The structural units A, B, and C are respectively:

[0009]

[0010] Wherein, the binary polymer composed of A and B has repeating structural units as shown in Formula I, and the binary polymer composed of A and C has repeating structural units as shown in Formula II:

[0011]

[0012]

[0013] Where m1, m2≥2, n≥2

[0014] To address the second technical problem mentioned above, this invention discloses a method for preparing the aforementioned bio-based UV-resistant resin film. Specifically, epoxy resin monomers are mixed with a bio-based curing agent EUGSFH, stirred and heated until homogeneous, then poured into a mold and heated to cure, yielding a bio-based epoxy resin.

[0015] The epoxy monomers mentioned herein include, but are limited to, the following structures.

[0016]

[0017] The molar ratio of the epoxy group of the epoxy monomer to the amino group of the bio-based diamine curing agent is 1:1.0 to 1.5, preferably 1:1.0 to 1.2, and more preferably 1:1.2.

[0018] The mixing temperature is 50-70℃, preferably 60℃; the curing temperature is 100-140℃, preferably 105-135℃.

[0019] The epoxy resin prepared by the method of the present invention has good optical shielding function, excellent heat resistance and good mechanical properties. Therefore, the present invention further proposes the application of the above-mentioned bio-based resin with tetrathiol curing agent in the preparation of resin film materials with optical shielding function.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0021] (1) The curing agent provided by the present invention is of biomass source, with high biological added value and high biological safety;

[0022] (2) The polymerization system described in this invention has a low polymerization temperature and a simple and mild preparation process.

[0023] (3) The polymer provided in this invention has good optical shielding function;

[0024] (4) The polymer provided in this invention has good heat resistance and mechanical properties. Attached Figure Description

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0026] Figure 1 The infrared test curves of the 3EP / EUGSFH and 2EP / EUGSFH polymers are shown, where a) is the IR curve of the 3EP / EUGSFH system and b) is the IR curve of the 2EP / EUGSFH system.

[0027] Figure 2 TG test curves for 3EP / EUGSFH and 2EP / EUGSFH polymers

[0028] Figure 3 UV-Vis transmittance test curves for 3EP / EUGSFH and 2EP / EUGSFH polymers; Detailed Implementation

[0029] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0030] Example 1: Preparation of 3EP / EUGSFH

[0031] Weigh 3EP (4.75 g, 12.0 mmol), curing agent EUGSFH (4.89 g, 9.0 mmol), and catalyst DMAP (1 / 1000, 9.64 mg) into a reaction flask. Mix thoroughly at 60 °C and then mill. Store at 105 °C for 2 h and 125 °C for 2 h. Allow to cool naturally to room temperature to obtain polymer 3EP / EUGSFH.

[0032] Example 2 Preparation of 2EP / EUGSFH

[0033] Weigh 2EP (5.44 g, 16.0 mmol), curing agent EUGSFH (4.32 g, 8.0 mmol), and catalyst DMAP (1 / 1000, 9.76 mg) into a reaction flask. Mix thoroughly at 60 °C and then mill. Store at 125 °C for 2 h and 135 °C for 2 h. Allow to cool naturally to room temperature to obtain polymer 2EP / EUGSFH.

[0034] Determined by infrared data, such as Figure 1 The 3EP / EUGSFH system shown has an infrared absorption peak of 860 cm⁻¹ for the epoxy group in 3EP. -1 and 910cm -1 ) and the infrared absorption peak (2570 cm⁻¹) of the thiol group in the curing agent EUGSFH. -1 The disappearance of the infrared absorption peak of the epoxy group in 2EP (860 cm⁻¹) indicates that the epoxy resin polymerization is complete; for the 2EP / EUGSFH system, the infrared absorption peak of the epoxy group in 2EP (860 cm⁻¹) indicates that the epoxy resin polymerization is complete; -1 and 910cm -1 ) and the infrared absorption peak (2570 cm⁻¹) of the thiol group in the curing agent EUGSFH. -1 The disappearance of ) indicates that the epoxy resin polymerization is complete.

[0035] Thermal stability analysis, such as Figure 2 The initial decomposition temperature of the 3EP / EUGSFH system is 352.8℃, the decomposition temperature corresponding to the decomposition of 30wt% is 384.0℃, the maximum decomposition temperature is 385.2℃, and the residual carbon at 800℃ is 20.9%. The initial decomposition temperature of the 2EP / EUGSFH system is 352.3℃, the decomposition temperature corresponding to the decomposition of 30wt% is 380.0℃, the maximum decomposition temperature is 384.33℃, and the residual carbon at 800℃ is 14.51%. Both systems have initial decomposition temperatures greater than 350℃, and both exhibit excellent heat resistance.

[0036] The UV-Vis transmittance of the prepared thin film is as follows: Figure 3As shown, the two systems provided by this invention have a transmittance of 0% for UVC and UVB; the 3EP / EUGSFH system has a UVA transmittance of less than 10.0%, a transmittance of 0.1% for 370nm wavelength ultraviolet light, a blue light blocking rate of 47.8%, and a blocking rate of 55.8% for 427nm wavelength ultraviolet light; the 2EP / EUGSFH system has a UVA transmittance of less than 41.3%, a transmittance of 370nm wavelength ultraviolet light of 33.6%, a blue light blocking rate of 52.5%, and a blocking rate of 67.3% for 427nm wavelength ultraviolet light.

[0037] Mechanical property tests, conducted using a universal testing machine, showed that the average tensile strength of 3EP / EUGSFH was 32.73±1.74 MPa, the average flexural strength was 59.83±0.40 MPa, and the average impact strength was 23.26±3.51 MPa; while the average tensile strength of 2EP / EUGSFH was 44.94±2.77 MPa, the average flexural strength was 71.60±1.01 MPa, and the average impact strength was 47.14±5.27 MPa.

[0038] This invention provides a method for constructing an optically shielding bio-based epoxy resin involving a tetrathiol curing agent. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A construction method for an optically shielding bio-based epoxy resin involving a tetrathiol curing agent, characterized in that... The curing agent used is a bio-based curing agent made from eugenol, and its structure is as follows: The epoxy monomers used have the following structures:

2. A novel binary polymer comprising a tetrathiol curing agent and an optically shielding bio-based epoxy resin, characterized in that structural units A and B or A and C constitute a novel binary polymer. Wherein structural units A, B, and C are respectively: in, The binary polymer composed of A and B has repeating structural units as shown in Formula I, and the binary polymer composed of A and C has repeating structural units as shown in Formula II. Where m1 and m2 ≥ 2, and n ≥ 2.

3. The construction of an optically shielding bio-based epoxy resin involving a tetrathiol curing agent according to claim 2, characterized in that... The bio-based curing agent EUGSFH was mixed with epoxy monomers 3EP and 2EP respectively and then injected into the mold for curing.

4. The construction of an optically shielding bio-based epoxy resin involving a tetrathiol curing agent according to claim 2, characterized in that... The epoxy monomers 3EP and 2EP are mixed with the bio-based curing agent EUGSFH in a molar ratio of epoxy groups to mercapto groups of 1:1.0 to 1.5; the mixing temperature is 50 to 70°C; and the curing temperature is 100 to 140°C.

5. The construction of an optically shielding bio-based epoxy resin involving a tetrathiol curing agent according to claim 2, characterized in that... The initial decomposition temperature is between 350℃ and 360℃, and the maximum decomposition temperature is between 380℃ and 390℃.

6. The construction of an optically shielding bio-based epoxy resin involving a tetrathiol curing agent according to claim 2, characterized in that... The prepared resin film with optical shielding function has a transmittance of 0% for short-wave ultraviolet (UVC) and medium-wave ultraviolet (UVB), a transmittance of less than 45% for long-wave ultraviolet (UVA), and a blue light blocking rate of 50-90%.

7. The construction of an optically shielding bio-based epoxy resin involving a tetrathiol curing agent according to claim 2, characterized in that... The prepared resin film with optical shielding function has good mechanical properties at room temperature, and the polymer composed of structure A and B or C has a tensile strength greater than 30 MPa. Its average bending strength is greater than 55 MPa; Its average impact strength is greater than 20 MPa.

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