CN-122011336-A - Epoxy vinyl resin with high ultraviolet aging resistance, preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to epoxy vinyl resin (VER) with high ultraviolet aging resistance, a preparation method and application thereof. The preparation method comprises the following steps of (S1) reacting diisocyanate with 4-hydroxybenzophenone (4-HBP) to synthesize an isocyanate-terminated precursor, (S2) mixing the precursor with a VER matrix, adding a catalyst and a diisocyanate curing agent, and (S3) curing by adopting a step heating program to obtain a final product. The diisocyanate has the dual functions of reacting with 4-HBP to form the isocyanate-terminated precursor and reacting the isocyanate-terminated precursor into the VER network in a chemical bond mode, and reacting with hydroxyl in the VER to form a final and functional three-dimensional crosslinked network as a curing agent of the VER to realize full curing. The method effectively solves the problem that the micromolecular ultraviolet absorbent is easy to migrate and run off, and obviously improves the ultraviolet aging resistance and durability of the resin.

Inventors

• LIN YU
• WANG SHUTAO
• LING SIQI
• YUAN LIZHI

Assignees

• 华东理工大学

Dates

Publication Date

20260512

Application Date

20260311

Claims (10)

1. 1. The preparation method of the epoxy vinyl resin with high ultraviolet aging resistance is characterized by comprising the following steps of: (S1) synthesizing a terminal isocyanate group precursor by reacting a diisocyanate compound with 4-HBP; (S2) mixing the precursor obtained in the step (S1) with a VER matrix, and adding diisocyanate as a curing agent, wherein the diisocyanate is preferably isophorone diisocyanate (IPDI); And (S3) casting the mixture obtained in the step (S2), and curing by adopting a step heating program to obtain the VER with high ultraviolet aging resistance.
2. 2. The preparation method of claim 1, wherein the step (S1) is specifically characterized by dissolving 4-HBP in an anhydrous organic solvent, dropwise adding diisocyanate into the solution in the presence of an inert atmosphere and a catalyst, controlling the reaction temperature to be 50 ℃, reacting 6-16 h after the dropwise adding, removing the solvent after the reaction is finished to obtain the isocyanate-terminated precursor, wherein the feeding mole ratio of 4-HBP to IPDI is 1:1.
3. 3. The preparation method according to claim 2, wherein the anhydrous organic solvent is one of anhydrous tetrahydrofuran, anhydrous acetone or anhydrous N, N-dimethylformamide, and the catalyst is dibutyltin dilaurate.
4. 4. The method according to claim 1, wherein in the step (S2), the precursor is added in an amount of 5 to 40% by mass based on the total mass of the final cured resin.
5. 5. The method according to claim 1, wherein in the step (S2), the total amount of the diisocyanate compound curing agent is determined such that the ratio of the total number of moles of isocyanate groups (-NCO) to the total number of moles of all hydroxyl groups (-OH) in the VER and the precursor is (0.1 to 1.1): 1.
6. 6. The process according to claim 1, wherein the diisocyanate is one or more selected from the group consisting of 2, 4-toluene diisocyanate (2, 4-TDI), 2, 6-toluene diisocyanate (2, 6-TDI), diphenylmethane diisocyanate (MDI), hexamethylene Diisocyanate (HDI) and dicyclohexylmethane diisocyanate (HMDI).
7. 7. The method of claim 1, wherein in step (S3), the step-heating curing procedure is to cure at 30-60 ℃ for 6-16 h, preferably 50 ℃ for 10 h, then to heat up to 70-90 ℃ at a rate of 0.5-1.5 ℃ per min, and cure at this temperature for 2-4 h, preferably 80 ℃ for 2h, and finally to continue heating up to 90-120 ℃ for 3-6 h, preferably 100 ℃ for 4 h.
8. 8. A high uv ageing resistance VER, characterized in that it is obtainable by a process according to any one of claims 1 to 7.
9. 9. Use of a high uv ageing resistance VER prepared by the method of any one of claims 1 to 7 for the preparation of an outdoor composite article.
10. 10. The use of claim 8, wherein the outdoor composite article comprises a wind blade, an outdoor building component, or a vehicle housing.

Description

Epoxy vinyl resin with high ultraviolet aging resistance, preparation method and application thereof Technical Field The invention relates to the technical field of high polymer materials, in particular to epoxy vinyl resin with high ultraviolet aging resistance, a preparation method and application thereof, and especially relates to a modification method for grafting a 4-hydroxybenzophenone (4-HBP) ultraviolet absorption unit into a VER cross-linked network in a chemical bond mode through specific diisocyanate, so that the resin is endowed with long-acting and stable ultraviolet aging resistance, and a material obtained by the modification method. Background Epoxy vinyl resin (VINYL ESTER RESIN, VER) is a high-performance thermosetting resin prepared by the reaction of epoxy resin and unsaturated monoacid (such as methacrylic acid), has excellent mechanical property, adhesiveness and chemical resistance of the epoxy resin and good processing manufacturability of unsaturated polyester, and is widely applied to the fields of composite materials, anti-corrosion engineering, electronic and electric and the like. However, VER molecular structure contains unsaturated double bond and aromatic ring, and photooxidation reaction easily occurs under long-term ultraviolet irradiation, so that yellowing, surface chalking, loss of gloss and rapid reduction of mechanical properties of the material are caused. This problem severely limits the application of VERs in long-term outdoor exposure scenarios such as wind blades, outdoor building materials, vehicle housings, and the like. Therefore, the ultraviolet aging resistance of the VER is improved, and the VER is an important research direction for expanding the application prospect of the VER. At present, the common method for improving the ultraviolet aging resistance of the high polymer material mainly comprises the addition of an ultraviolet absorber, an ultraviolet shielding agent or an antioxidant and the like. Wherein, adding small molecular ultraviolet absorbent (such as benzophenone and benzotriazole compounds) is the most simple and economical ultraviolet-resistant modification means in industry. However, the small molecular ultraviolet absorber is easy to migrate, volatilize or precipitate in the use process of the material, so that the ultraviolet resistance is obviously reduced along with the prolonged use time, and the precipitated auxiliary agent can also cause environmental pollution. To solve the problem of small molecule adjuvant migration, researchers have tried a variety of chemical modification methods. CN 121471684a discloses a cable polymer composite material for wind power blades, which consists of a polymer base material, a reinforcing material, a polymer modified material, a functional additive and the like, wherein the functional additive consists of an ultraviolet resistant agent, an antioxidant, a silane coupling agent and nano titanium dioxide (TiO 2), and all components are uniformly dispersed in a matrix through a physical blending mode. However, the anti-ultraviolet agent in the system is still dispersed in a small molecular form, and the risk of migration, volatilization or precipitation exists in the long-term outdoor use process, so that the anti-ultraviolet performance is attenuated along with the extension of the service time. CN121182324a discloses an epoxy resin insulating paint with high toughness and high ultraviolet ageing resistance and a preparation method thereof, the paint is composed of a TiO 2 @PDA@BTA nano material, epoxy resin and a curing agent, a polydopamine layer and a benzotriazole layer are sequentially constructed on the surface of nano TiO 2, and full-band coverage is realized by utilizing the absorption capability of TiO 2 and BTA on ultraviolet light of different wave bands. However, the system depends on the design and synthesis of complex multilayer core-shell structure nano particles, the preparation process involves the procedures of multi-step reaction, ultrasonic dispersion, centrifugal washing, drying and the like, the process is complex, and the cost is high. CN121045871a discloses a broad spectrum ultraviolet absorbent of sandwich structure, its preparation method and application, the absorbent uses aminated graphene oxide as "face", uses benzotriazole ultraviolet absorbent as "discrete point", and self-assembles through hydrogen bond and pi-pi bond action to form "discrete point/face/discrete point" sandwich structure. However, this system relies on non-covalent interactions between graphene oxide and the uv absorber, which physical adsorption may be desorbed during long-term use due to solvent attack, temperature changes, or mechanical stress, resulting in gradual shedding of the uv absorber. CN 120590896a discloses a high temperature resistant and weather resistant epoxy resin adhesive and a preparation method thereof, and the adhesive realizes the synergic promotion of high temperature resistance, ul