Medium-temperature curing high-toughness solid epoxy vinyl ester resin composition as well as preparation method and application thereof

Abstract

The invention discloses a medium-temperature curing high-toughness epoxy vinyl ester resin composition as well as a preparation method and application thereof. The epoxy vinyl ester resin composition is prepared from the following raw materials in parts by mass: 40 to 70 parts of bisphenol A type epoxy resin, 8 to 30 parts of polyether polyol glycidyl ether, 16 to 49.3 parts of unsaturated monocarboxylic acid, 0.05 to 0.5 part of a catalyst, 0.05 to 0.8 part of a polymerization inhibitor, 0.5 to 2 parts of a curing agent, 5 to 20 parts of a low-melting-point monomer and 8 to 15 parts of a toughening agent. According to the invention, a low-melting-point monomer is introduced into epoxy vinyl ester resin and is compounded with high-molecular-weight epoxy vinyl ester resin and polyether polyol glycidyl ether epoxy vinyl ester resin, and a medium-temperature curing agent is adopted, so that solid vinyl ester resin suitable for a medium-temperature hot melting process is prepared; meanwhile, a certain proportion of core-shell particle toughening agent is added, so that the heat resistance, the mechanical property and the toughness of the cured epoxy vinyl ester resin are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high polymer materials, and particularly relates to a medium-temperature curing high-toughness epoxy vinyl ester resin composition and a preparation method and application thereof. BACKGROUND

[0002] The epoxy vinyl ester resin is usually prepared by ring-opening polymerization of epoxy resin and acrylic acid or methacrylic acid, and has the advantages of both epoxy resin and unsaturated polyester, such as excellent mechanical properties, chemical and seawater corrosion resistance, and rapid curing, and its application has gradually expanded to the fields of transportation, oil fields, oceans and the like. In particular, in the field of marine vessels, the epoxy vinyl ester resin is combined with reinforcing materials such as carbon fiber or glass fiber, and has become one of the most commonly used resin matrix composites in the field of marine vessels.

[0003] The epoxy vinyl ester resin is usually prepared by ring-opening polymerization of epoxy resin and acrylic acid or methacrylic acid, and has the advantages of both epoxy resin and unsaturated polyester, such as excellent mechanical properties, chemical and seawater corrosion resistance, and rapid curing, and its application has gradually expanded to the fields of transportation, oil fields, oceans and the like. In particular, in the field of marine vessels, the epoxy vinyl ester resin is combined with reinforcing materials such as carbon fiber or glass fiber, and has become one of the most commonly used resin matrix composites in the field of marine vessels.

[0004] At the same time, the epoxy vinyl ester resin has a highly cross-linked chemical structure, and has the disadvantages of high brittleness and poor impact resistance, so it is necessary to toughen the epoxy vinyl ester resin and its composite material, and improve the use reliability of the epoxy vinyl ester resin and its composite material. SUMMARY

[0005] In view of the defects of the prior art, the present application provides a medium-temperature curing high-toughness solid epoxy vinyl ester resin composition and a preparation method and application thereof. By using a medium-temperature curing agent, the present application can reduce the curing temperature of the epoxy vinyl ester resin and improve the production efficiency in the production and processing process of the epoxy vinyl ester resin prepreg. Meanwhile, by introducing a low-melting-point monomer into the epoxy vinyl ester resin, compounding the low-melting-point monomer with a high-molecular-weight epoxy vinyl ester resin and a polyether polyol glycidyl ether epoxy vinyl ester resin, and adding a certain proportion of core-shell particle toughening agent, the process performance, heat resistance, mechanical properties and toughness of the epoxy vinyl ester resin cured product are improved.

[0006] To achieve the above-mentioned application purposes, the present application adopts the following technical solutions: In a first aspect, the present application provides a medium-temperature curing high-toughness solid epoxy vinyl ester resin composition.

[0007] The medium-temperature curing high-toughness solid epoxy vinyl ester resin composition comprises the following raw materials by mass: Bisphenol A type epoxy resin 40-70 parts Polyether polyol glycidyl ether 8-30 parts Unsaturated monocarboxylic acid 16-49.3 parts Catalyst 0.05-0.5 parts Polymerization inhibitor 0.05-0.8 parts Curing agent 0.5-2 parts Low-melting-point monomer 5-20 parts Core-shell particle toughening agent 8-15 parts.

[0008] In some embodiments of the present application, the epoxy equivalent weight of the bisphenol A type epoxy resin is 185-1000, and the molecular weight is 370-2000. In a specific embodiment of the present application, the bisphenol A epoxy resin is selected from one or more of E51 type epoxy resin, E44 type epoxy resin, E20 type epoxy resin and E12 type epoxy resin.

[0009] In some embodiments of the present application, the epoxy equivalent weight of the polyether polyol glycidyl ether is 115-320, and the molecular weight is 230-640. In a specific embodiment of the present application, the polyether polyol glycidyl ether is selected from one or more of polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether and 1,6-hexanediol diglycidyl ether.

[0010] In some embodiments of the present invention, the catalyst is one or more of tetrabutylammonium bromide, benzyltrimethylammonium chloride, and benzyltriethylammonium chloride.

[0011] In some embodiments of the present invention, the unsaturated monocarboxylic acid is one or more of methacrylic acid and acrylic acid.

[0012] In some embodiments of the present invention, the polymerization inhibitor is selected from one or more of hydroquinone, p-benzoquinone, tert-butylcatechol, tert-butylhydroquinone, and p-hydroxyanisole.

[0013] In some embodiments of the present invention, the curing agent is selected from benzoyl peroxide or tert-butyl peroxide-2-ethylhexanoate.

[0014] In some embodiments of the present invention, the low-melting-point monomer is selected from one or more of maleimide containing an indmann structure, 4,4'-bis(3-N-maleimide-phenoxy)diphenyl sulfone, and 4-allyloxyphenylmaleimide.

[0015] The maleimide containing the indane structure has the structural formula shown in Formula 1:

[0016] The 4,4'-bis(3-N-maleimide-phenoxy)diphenyl sulfone has the structural formula shown in Formula 2:

[0017] The 4-allyloxyphenylmaleimide has the structural formula shown in Formula 3:

[0018] In some embodiments of the present invention, the core-shell particle toughening agent is a core-shell styrene-butadiene rubber particle; in one specific embodiment of the present invention, the core-shell particle toughening agent is an epoxy resin toughening agent of Kaneka Corporation of Japan, brand name MX125.

[0019] In a second aspect, the present invention provides a method for preparing the medium-temperature curing high-toughness solid epoxy vinyl ester resin composition described in the first aspect.

[0020] The preparation method includes the following steps: (1) Mix bisphenol A type epoxy resin, polyether polyol glycidyl ether and core-shell particle toughening agent evenly, heat to 100-110℃ and stir for 20-30 min, add unsaturated monocarboxylic acid to the above reaction system, control the temperature of the reaction system to 80-85℃, and stir for 10-20 min. (2) Add the polymerization inhibitor to the above reaction system, stir for 10-20 min, add the catalyst, and react at 110-120℃ for 5.0-6.0 hours. During the heat preservation reaction, control the acid value of the reaction system to be no more than 6 mg KOH / g to obtain a uniform reaction product. (3) Cool the reaction product obtained in step (2) to 78-85℃, add a low melting point monomer, and keep the reaction at 78-85℃ for 1-2 hours to obtain a dark brown-yellow reaction product. (4) Cool the reaction product obtained in step (3) to 55-58℃, add curing agent, stir evenly, and obtain a medium-temperature curing high-toughness solid epoxy vinyl ester resin composition.

[0021] According to some embodiments of the present invention, in step (4), the stirring time may be 10-15 min.

[0022] Thirdly, the present invention provides a curing method for the medium-temperature curing high-toughness solid epoxy vinyl ester resin composition described in the first aspect.

[0023] The curing method provided by the present invention includes the following steps: curing the epoxy vinyl ester resin composition at 80-95°C.

[0024] According to one specific embodiment of the present invention, curing is carried out according to the procedure of 80℃ / 2h, 95℃ / 2h.

[0025] Fourthly, the present invention provides the application of the medium-temperature curing high-toughness solid epoxy vinyl ester resin composition described in the first aspect in the preparation of resin-based composite materials.

[0026] The epoxy vinyl ester resin composition of this invention simultaneously incorporates low-melting-point monomers and toughening agents, and employs a medium-temperature curing agent. Research has shown that by introducing low-melting-point monomers into the epoxy vinyl ester resin and compounding it with high-molecular-weight epoxy vinyl ester resin and polyether polyol glycidyl ether epoxy vinyl ester resin, a solid vinyl ester resin suitable for hot-melt processes can be prepared. Utilizing the characteristic that low-melting-point monomers are solid at room temperature but melt and flow at lower temperatures, a solid vinyl ester resin with good flow properties at medium temperatures is prepared by compounding it with a medium-temperature curing agent. The resin exhibits good wetting of carbon fibers at medium temperatures, making it suitable for preparing high-performance resin-based composite materials. Furthermore, this invention incorporates a certain proportion of core-shell particle toughening agents, which simultaneously improves the heat resistance, mechanical properties, and toughness of the cured epoxy vinyl ester resin.

[0027] Compared with the prior art, the present invention has the following beneficial effects: (1) The epoxy vinyl ester resin composition of the present invention incorporates a low-melting-point monomer. Utilizing the characteristic that the low-melting-point monomer is solid at room temperature but melts and flows at a relatively low temperature, it is compounded with a high molecular weight epoxy vinyl ester resin and a polyether polyol glycidyl ether epoxy vinyl ester resin to prepare a solid vinyl ester resin suitable for hot-melt processes. Simultaneously, a medium-temperature curing agent is used to prepare a solid vinyl ester resin with good flow properties at medium temperatures. The resin exhibits good wetting with carbon fibers at medium temperatures, enabling the preparation of high-performance resin-based composite materials. This process has a low curing temperature, does not rely on large heating devices, and features energy-saving and high production efficiency.

[0028] (2) The present invention adds a core-shell particle toughening agent to epoxy vinyl ester resin. The core-shell particle toughening agent is liquid, has good dispersibility in the resin, is not easy to agglomerate, and its addition significantly improves the toughness of vinyl ester resin without reducing its heat resistance. Attached Figure Description

[0029] Figure 1 Transmission electron microscope (TEM) image of the vinyl resin cured product prepared in Example 1.

[0030] Figure 2 shows the glass transition temperature of the vinyl ester resin cured product prepared in Example 1. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0032] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0033] In the quantitative experiments in the following examples, three replicate experiments were set up, and the average value of the results was taken.

[0034] The preparation method of the vinyl ester resin cured product, the viscosity of the vinyl ester resin, the flexural properties of the cured product, the impact strength, and the glass transition temperature test method are as follows in the following examples: Preparation of cured resin: The epoxy vinyl ester resin composition was cured according to the procedure of 80℃ / 2h, 95℃ / 2h.

[0035] The resin viscosity was tested according to GB / T7193-2008 using a rotational viscometer.

[0036] Bending strength was tested according to GB / T 2567-2021 using an Instron universal testing machine.

[0037] The flexural strength retention rate after boiling was tested according to GB / T 2573-2008.

[0038] Impact strength was tested according to standard GB2567-2021 using a Chengde JC-25 simply supported beam impact testing machine.

[0039] The glass transition temperature of the cured resin was tested using a TA Q-200 thermometer at a heating rate of 10°C / min.

[0040] The low-melting-point monomers used in the following embodiments were synthesized in-house, and the specific preparation method is as follows: (1) Maleimide containing an indane structure (structural formula shown in Formula 1): Add maleic anhydride (19.61 g, 0.1 mol), 110 g of DMAc, and 20 g of toluene to a 500 mL three-necked flask in sequence. After the maleic anhydride is completely dissolved, add dropwise a solution prepared by dissolving 26.63 g of indanediamine in 100 g of DMAc. Keep the solution at room temperature for 3 h. Add 0.2 g of p-toluenesulfonic acid to the above system, heat to 110-115 °C, maintain the temperature for 5 h, then add boiling water containing saturated NaHCO3 for extraction, wash until neutral, remove the solvent by rotary evaporation, and dry to obtain 39.2 g of light yellow maleimide containing an indane structure, with a yield of 92%. 1 H NMR (CDCl3, 400MHz): δ=1.03, 1.34, 1.67 (9H,3Me); δ=2.23~2.26, 2.44~2.47(2H, CH2); δ=7.12~7.16 (4H, MI); 7.19~7.31(7H, PhH).

[0041] (2) 4,4'-bis(3-N-maleimide-phenoxy)diphenyl sulfone (structural formula shown in Formula 2): Add maleic anhydride (19.61 g, 0.1 mol), DMAc 180 g, and toluene 20 g to a 500 mL three-necked flask in sequence. After the maleic anhydride is completely dissolved, add 43.25 g of a solution prepared by dissolving 4,4'-bis(3-aminophenoxy)diphenyl sulfone in 106 g of DMAc dropwise. Keep the solution at room temperature for 3 h. Add 0.2 g of p-toluenesulfonic acid to the above system, heat to 110-115 °C, maintain the temperature for 6 h, then add boiling water containing saturated NaHCO3 for extraction, wash until neutral, remove the solvent by rotary evaporation, and dry to obtain 55.0 g of light yellow 4,4'-bis(3-N-maleimide-phenoxy)diphenyl sulfone, with a yield of 93%. 1 H NMR (CDCl3, 400MHz): δ=7.10~7.15 (4H, MI); 7.08~8.16 (8H, PhH).

[0042] (3) 4-Allyloxyphenylmaleimide (CAS 107249-76-3, structural formula as shown in Formula 3): 8.2 g (0.084 mol) of maleic anhydride was added to a flask equipped with a thermometer and stirrer and dissolved in 159 g of toluene and 1 g of DMF. While maintaining the temperature below 10°C in an ice bath, 11.3 g (0.076 mol) of 4-allyloxyaniline dissolved in 15 g of DMF was added dropwise, and the mixture was reacted at 25°C for 2 hours. Subsequently, 1 g of 95% sulfuric acid was added, and the mixture was reacted at 110°C for 5 hours, followed by distillation of toluene under reduced pressure. 120 g of ethyl acetate was added and the mixture was separated three times, then separated twice with a 2% aqueous sodium bicarbonate solution. The organic layer was dehydrated with sodium sulfate, and ethyl acetate was distilled off under reduced pressure using a rotary evaporator to give 15 g (0.066 mol, 87% yield) of N-allyloxyphenylmaleimide. 1 H NMR (CDCl3, 400MHz): δ= 5.31~5.16 (2H), 5.9 (1H), 7.06~6.92 (4H, PhH), 7.11~7.15 (2H, MI).

[0043] Example 1 (1) 20g of bisphenol A type epoxy resin (E-51), 20g of bisphenol A type epoxy resin (E-12), 10g of polypropylene glycol diglycidyl ether (molecular weight 380) and 8g of core-shell particle toughening agent (Kanefuchi Chemical, Japan, brand name MX125) were added to a 250ml three-necked flask equipped with a mechanical stirrer. The temperature was raised to 100℃ and stirred for 25min. 16.00g of methacrylic acid was added to the above reactants. The temperature of the reaction system was controlled at 85℃ and stirred for 20min. (2) Add 0.05 g of hydroquinone to the above reaction system, stir for 15 min, add 0.05 g of tetrabutylammonium bromide, react at 120 °C for 6.0 h, control the acid value of the reaction system to 6 mg KOH / g during the reaction, stop the reaction, and obtain a uniform reaction product. (3) Cool the above reaction product to 85°C, add 10g of maleimide containing indane structure, and keep the reaction at 78°C for 1h to obtain a dark brown-yellow reaction product. (4) Cool the reaction product to 55°C, add 1g of benzoyl peroxide, stir for 10min, and obtain a medium-temperature curing high-toughness solid epoxy vinyl ester resin composition.

[0044] The epoxy vinyl ester resin composition obtained above was cured according to the procedure of 80℃ / 2h, 95℃ / 2h to obtain the epoxy vinyl ester resin cured product.

[0045] Transmission electron microscopy (TEM) was performed on the cured epoxy vinyl ester resin, and the results are as follows: Figure 1 As shown. From Figure 1 It can be seen that the core-shell toughening agent is uniformly dispersed in the resin matrix.

[0046] Example 2 (1) Add 50g of bisphenol A type epoxy resin (E-44), 20g of bisphenol A type epoxy resin (E-20), 30g of polypropylene glycol diglycidyl ether (molecular weight 500) and 15g of core-shell particle toughening agent (Kanefuchi Chemical, Japan, brand name MX125) to a 250ml three-necked flask equipped with a mechanical stirrer, heat to 100℃ and stir for 30min, add 27.38g of acrylic acid to the above reactants, control the temperature of the reaction system to 80℃, and stir for 10min; (2) Add 0.5g of p-benzoquinone to the above reaction system, stir for 20min, add 0.2g of benzyltrimethylammonium chloride, react at 115℃ for 5.0 hours, control the acid value of the reaction system to 4mg KOH / g during the reaction, stop the reaction, and obtain a uniform reaction product; (3) Cool the above reaction product to 85°C, add 20g of 4,4'-bis(3-N-maleimide-phenoxy)diphenyl sulfone, and keep the reaction at 85°C for 2h to obtain a dark brown-yellow reaction product. (4) Cool the reaction product to 58°C, add 2g of tert-butyl peroxide-2-ethylhexanoate, stir for 15min to obtain a medium-temperature curing high-toughness solid epoxy vinyl ester resin composition.

[0047] Example 3 (1) 30g of bisphenol A epoxy resin (E-51), 10g of bisphenol A epoxy resin (E-20), 20g of bisphenol A epoxy resin (E-12), 20g of polyethylene glycol diglycidyl ether (molecular weight 500) and 10g of core-shell particle toughening agent (Kanefuchi Chemical, Japan, brand name MX125) were added to a 250ml three-necked flask equipped with a mechanical stirrer. The temperature was raised to 110℃ and stirred for 20min. 49.32g of methacrylic acid was added to the above reactants. The temperature of the reaction system was controlled at 82℃ and stirred for 15min. (2) Add 0.1 g of tert-butylcatechol and 0.7 g of p-hydroxyanisole to the above reaction system, stir for 20 min, add 0.5 g of benzyltriethylammonium chloride, react at 110 °C for 5.0 h, control the acid value of the reaction system to 5 mg KOH / g during the reaction, stop the reaction, and obtain a uniform reaction product. (3) Cool the above reaction product to 80°C, add 5g of 4-allyloxyphenylmaleimide, and keep the reaction at 85°C for 2h to obtain a dark brown-yellow reaction product. (4) Cool the reaction product to 58°C, add 0.5g of tert-butyl peroxide-2-ethylhexanoate, stir for 15min to obtain a medium-temperature curing high-toughness solid epoxy vinyl ester resin composition.

[0048] Example 4 (1) Add 40g of bisphenol A type epoxy resin (E-44), 30g of polyethylene glycol diglycidyl ether (molecular weight 500) and 15g of core-shell particle toughening agent (Kanefuchi Chemical, Japan, brand name MX125) to a 250ml three-necked flask equipped with a mechanical stirrer, heat to 100℃ and stir for 20min, add 27.86g of methacrylic acid to the above reactants, control the temperature of the reaction system at 80℃, and stir for 20min; (2) Add 0.05g hydroquinone and 0.7g p-hydroxyanisole to the above reaction system, stir for 15min, add 0.35g benzyltrimethylammonium chloride, react at 115℃ for 5.5 hours, control the acid value of the reaction system to 5.3mg KOH / g during the reaction, stop the reaction, and obtain a uniform reaction product; (3) Cool the above reaction product to 78°C, add 20g of 4-allyloxyphenylmaleimide, and keep the reaction at 80°C for 1h to obtain a dark brown-yellow reaction product. (4) Cool the reaction product to 55°C, add 0.5g of benzoyl peroxide, stir for 10min to obtain a medium-temperature curing high-toughness solid epoxy vinyl ester resin composition.

[0049] Example 5 (1) 30g of bisphenol A type epoxy resin (E-51), 20g of bisphenol A type epoxy resin (E-20), 30g of 1,6-hexanediol diglycidyl ether (molecular weight 230) and 12g of core-shell particle toughening agent (Kanefuchi Chemical, Japan, brand name MX125) were added to a 250ml three-necked flask equipped with a mechanical stirrer. The temperature was raised to 100℃ and stirred for 25min. 39.04g of methacrylic acid was added to the above reactants. The temperature of the reaction system was controlled at 82℃ and stirred for 18min. (2) Add 0.1 g of p-benzoquinone and 0.6 g of tert-butylcatechol to the above reaction system, stir for 10 min, add 0.5 g of tetrabutylammonium bromide, react at 115 °C for 5.5 h, and control the acid value of the reaction system to 5.3 mg KOH / g during the reaction. Stop the reaction to obtain a uniform reaction product. (3) Cool the above reaction product to 78°C, add 20g of maleimide containing indane structure, and keep the reaction at 80°C for 1h to obtain a dark brown-yellow reaction product. (4) Cool the reaction product to 58°C, add 0.6g of tert-butyl peroxide-2-ethylhexanoate, stir for 15min to obtain a medium-temperature curing high-toughness solid epoxy vinyl ester resin composition.

[0050] Comparative Example 1 (1) 20g of bisphenol A type epoxy resin (E-51), 20g of bisphenol A type epoxy resin (E-12), 10g of polypropylene glycol diglycidyl ether (molecular weight 380) and 8g of core-shell particle toughening agent (Kanefuchi Chemical, Japan, brand name MX125) were added to a 250ml three-necked flask equipped with a mechanical stirrer. The temperature was raised to 100℃ and stirred for 25min. 16.00g of methacrylic acid was added to the above reactants. The temperature of the reaction system was controlled at 85℃ and stirred for 20min. (2) Add 0.05 g of hydroquinone to the above reaction system, stir for 15 min, add 0.05 g of tetrabutylammonium bromide, react at 120 °C for 6.0 h, control the acid value of the reaction system to 6 mg KOH / g during the reaction, stop the reaction, and obtain a uniform reaction product. (3) Cool the reaction product to 55°C, add 1g of benzoyl peroxide, stir for 10min, and obtain a medium-temperature curing high-toughness solid epoxy vinyl ester resin composition.

[0051] The difference between Comparative Example 1 and Example 1 is that maleimide containing an indane structure is not added.

[0052] Comparative Example 2 (1) Add 20g of bisphenol A type epoxy resin (E-51), 20g of bisphenol A type epoxy resin (E-12) and 10g of polypropylene glycol diglycidyl ether (molecular weight 380) to a 250ml three-necked flask equipped with a mechanical stirrer, heat to 100℃ and stir for 25min, add 16.00g of methacrylic acid to the above reactants, control the temperature of the reaction system at 85℃, and stir for 20min; (2) Add 0.05 g of hydroquinone to the above reaction system, stir for 15 min, add 0.05 g of tetrabutylammonium bromide, react at 120 °C for 6.0 h, control the acid value of the reaction system to 6 mg KOH / g during the reaction, stop the reaction, and obtain a uniform reaction product. (3) Cool the above reaction product to 85°C, add 10g of maleimide containing indane structure, and keep the reaction at 78°C for 1h to obtain a dark brown-yellow reaction product. (4) Cool the reaction product to 55°C, add 1g of benzoyl peroxide, stir for 10min, and obtain a medium-temperature curing high-toughness solid epoxy vinyl ester resin composition.

[0053] The difference between Comparative Example 2 and Example 1 is that no core-shell particle toughening agent was added.

[0054] The performance (viscosity of vinyl ester resin, flexural properties of cured products, impact strength and glass transition temperature) test results of Examples 1-5 and Comparative Examples 1-2 are shown in Table 1.

[0055] Table 1 summarizes the performance test results of Examples 1-5 and Comparative Examples 1-2.

[0056] As can be seen from Table 1, 1. Compared with Comparative Example 1, Examples 1-5 added low-melting-point monomers. Utilizing the characteristic that low-melting-point monomers are solid at room temperature but melt and flow at lower temperatures, they were compounded with high molecular weight epoxy vinyl ester resin and polyether polyol glycidyl ether epoxy vinyl ester resin to prepare solid vinyl ester resins suitable for hot-melt processes. The resin composition exhibits good processability at medium temperatures. After curing using a medium-temperature program of 80℃ / 2h, 95℃ / 2h, the flexural strength of the prepared castings ranged from 118 to 132 MPa, the flexural strength retention rate after boiling water was between 90.5% and 91.8%, the glass transition temperature was between 103 and 109℃, and the impact strength was between 35.6 and 52.0 kJ / m. 2 Between these, it exhibits excellent overall performance. Comparative Example 1, which did not contain low-melting-point monomers, had too high viscosity at medium temperature, making it impossible to prepare specimens and unsuitable for medium-temperature hot-melt processes.

[0057] 2. Compared with Comparative Example 2, Examples 1-5 incorporated core-shell particle toughening agents, which significantly improved the impact toughness of the cured resin, with an impact toughness ranging from 35.6 to 52.0 kJ / m. 2 The glass transition temperature is between 103 and 109 °C, and the impact strength is 20.5 kJ / m² compared to Comparative Example 2 without core-shell particles. 2 There is a significant improvement, and the heat resistance is not reduced. (The glass transition temperatures of Examples 1-5 are all slightly higher than the glass transition temperature of the Comparative Example 2 sample).

[0058] The present invention has been described in detail above. For those skilled in the art, the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. Although specific embodiments have been given, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein. Some of the essential features can be applied within the scope of the following appended claims.

Claims

1. A medium temperature curing high toughness solid epoxy vinyl ester resin composition comprising the following ingredients in parts by mass: bisphenol A type epoxy resin 40-70 parts polyether polyol glycidyl ether 8-30 parts unsaturated monocarboxylic acid 16-49.3 parts catalyst 0.05-0.5 parts polymerization inhibitor 0.05-0.8 parts curing agent 0.5-2 parts low melting point monomer 5-20 parts core-shell particle toughening agent 8-15 parts.

2. The medium temperature vulcanizable high toughness solid epoxy vinyl ester resin composition according to claim 1, characterized in that: The bisphenol A type epoxy resin has an epoxy equivalent weight of 185-1000 and a molecular weight of 370-2000; further, the bisphenol A epoxy resin is selected from one or more of E51 type epoxy resin, E44 type epoxy resin, E20 type epoxy resin, and E12 type epoxy resin.

3. The medium temperature vulcanizable high toughness solid epoxy vinyl ester resin composition according to claim 1 or 2, characterized in that: The polyether polyol glycidyl ether has an epoxy equivalent weight of 115-320 and a molecular weight of 230-640; further, the polyether polyol glycidyl ether is selected from one or more of polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and 1,6-hexanediol diglycidyl ether. The curing agent is selected from one of benzoyl peroxide or tert-butyl peroxy-2-ethylhexanoate.

4. The medium temperature vulcanizable high toughness solid epoxy vinyl ester resin composition according to any one of claims 1-3, characterized in that: The low melting point monomer is selected from one or more of maleimide containing an indane structure, 4,4'-bis(3-N-maleimide-phenoxy)diphenyl sulfone, and 4-allyloxyphenyl maleimide.

5. The medium temperature vulcanizable high toughness solid epoxy vinyl ester resin composition according to any one of claims 1-4, characterized in that: The catalyst is one or more of tetrabutylammonium bromide, benzyltrimethylammonium chloride, and benzyltriethylammonium chloride.

6. The medium temperature vulcanizable high toughness solid epoxy vinyl ester resin composition according to any one of claims 1-5, characterized in that: The unsaturated monocarboxylic acid is methacrylic acid or acrylic acid. The polymerization inhibitor is selected from one or more of hydroquinone, p-benzoquinone, tert-butyl catechol, tert-butyl hydroquinone, and p-hydroxyanisole. The core-shell particle toughening agent is core-shell styrene-butadiene rubber particles.

7. The medium temperature vulcanizable high toughness solid epoxy vinyl ester resin composition according to any one of claims 1 to 6, characterized in that:

8. A method for preparing the medium temperature curing high toughness solid epoxy vinyl ester resin composition of any one of claims 1-7, comprising the following steps: (1) uniformly mixing the bisphenol A type epoxy resin, the polyether polyol glycidyl ether, and the core-shell particle toughening agent, heating to 100-110°C, and stirring for 20-30 min, adding the unsaturated monocarboxylic acid to the above reaction system, controlling the reaction system temperature to be 80-85°C, and stirring for 10-20 min; (2) adding the polymerization inhibitor to the above reaction system, stirring for 10-20 min, then adding the catalyst, and reacting at 110-120°C for 5.0-6.0 hours, while controlling the acid value of the reaction system to be no more than 6 mg KOH / g, to obtain a uniform reaction product; (3) cooling the reaction product obtained in step (2) to 78-85°C, adding the low melting point monomer, and reacting at 78-85°C for 1-2 h to obtain a dark brownish yellow reaction product; (4) cooling the reaction product obtained in step (3) to 55-58°C, adding the curing agent, and stirring uniformly to obtain the medium temperature curing high toughness solid epoxy vinyl ester resin composition.

9. Use of the medium temperature curing high toughness solid epoxy vinyl ester resin composition of any one of claims 1-7 in the preparation of resin matrix composites. ​ 10. A curing method of the high-toughness solid-state epoxy vinyl ester resin composition of any one of claims 1 to 7, comprising the step of curing the epoxy vinyl ester resin composition of any one of claims 1 to 7 at 80 to 95°C. Further, the curing is performed according to a procedure of 80°C / 2h, 95°C / 2h.

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