Cardanol-based vinyl resin modifier as well as preparation method and application thereof

Abstract

The invention relates to the technical field of coating resin, in particular to a cardanol-based vinyl resin modifier as well as a preparation method and application thereof, the cardanol-based vinyl resin modifier has a structural formula as shown in a formula I: # imgabs0 #, in the formula I, R is one of CH3CH2-or CH = CH2. The problem that the epoxy vinyl ester resin has high brittleness and is prone to brittle fracture under complex working conditions such as impact and vibration is effectively solved, the flexibility and elasticity of the resin composition are improved, the resin is not prone to fracture due to external force, the resin material is endowed with excellent flexibility and impact resistance, and the service life of the resin material is prolonged. Therefore, deformation can be adapted without damage, and the requirements of high-performance application scenes are met.

Description

Technical Field

[0001] The present application relates to the technical field of coating resins, and in particular to a cardanol-based vinyl resin modifier, a preparation method thereof, and applications thereof. Background Art

[0002] Epoxy vinyl ester resins, as an important class of thermosetting resins, are widely used in chemical corrosion protection, aerospace, automotive manufacturing, and other fields. Their excellent mechanical properties, heat resistance, and easy curing characteristics play a key role in chemical corrosion protection, significantly promoting the development of related industries.

[0003] Epoxy vinyl ester resin is a type of thermosetting resin developed from epoxy resin. It is prepared by a ring-opening addition reaction between epoxy resin and methacrylic acid. This unique synthesis method makes epoxy vinyl ester resin closely related to epoxy resin in chemical structure, thus inheriting many of the advantages of epoxy resin, such as excellent adhesion and chemical resistance. However, it also inherits the disadvantages of epoxy resin. Epoxy resin itself is relatively brittle, and this defect is also reflected in epoxy vinyl ester resin. Due to its low impact strength and low elongation at break, it is prone to brittle fracture when faced with complex working conditions such as impact and vibration, limiting its use in some applications with extremely stringent requirements on material toughness.

[0004] At present, in order to solve the brittleness problem of epoxy vinyl ester resin, methods including polyurethane, "soft monomer" acrylic, and silicone resin modification are adopted. However, the existing means can only enhance a single toughness or impact resistance, and it is difficult to strike a balance between hardness and elasticity. Especially in terms of improving toughness, the modified vinyl resin still cannot fully meet the needs of high-performance application scenarios, especially in special working conditions that require extremely high toughness and stability. Summary of the Invention

[0005] In order to effectively improve the brittleness of epoxy vinyl ester resin, which makes it prone to brittle fracture when facing complex working conditions such as impact and vibration, the present application provides a cardanol-based vinyl resin modifier, a preparation method and application thereof.

[0006] In the first aspect, the present application provides a structural formula as shown in Formula I: In formula I, R is one of CH3CH2- or CH=CH2.

[0007] The applicant has found that the modifier having the above structure has good performance in improving the brittle fracture of epoxy vinyl ester resin. This may be because the long-chain alkyl group contained in the cardanol-based vinyl resin modifier has good flexibility and rotatability, which can provide a large activity space between molecules. When the resin is subjected to external force, the long-chain alkyl group can buffer the stress through its own deformation, making the resin less likely to break due to external force, thereby giving the resin excellent flexibility; the cardanol-based vinyl resin modifier also has a unique cyclic unsaturated cycloolefin structure. Compared with straight chain and saturated cyclic structures, the molecular chain rotates and twists more easily, so that when the molecular chain is subjected to external force, it can more flexibly adapt to the external force through chain segment movement, rather than being easily broken like a rigid structure, thereby effectively improving the flexibility and elasticity of the vinyl resin. In addition, the oxygen atom in the ether bond has a certain lone pair of electrons, which gives the ether bond a certain degree of internal rotation freedom; this enables the molecular chain to move more flexibly and disperse stress through its own deformation, further enhancing the resin's anti-brittle fracture and anti-cracking properties. The presence of ester bonds also imparts a certain degree of flexibility and bendability to the molecular chain, making the resin less susceptible to breakage due to external forces. This gives the resin excellent flexibility and impact resistance, allowing the material to adapt to deformation without damage, thereby ensuring the resin's flexibility. Furthermore, the flexible structure in the cardanol-based vinyl resin modifier can penetrate deep into the molecular chains of the epoxy vinyl ester resin, increasing the mobility of the molecular chains, further improving the epoxy vinyl ester resin's flexibility, reducing the resin's brittleness after curing, and enhancing its impact resistance and cracking resistance. Furthermore, the presence of groups such as ester groups can improve the compatibility of the modifier with the epoxy vinyl ester resin. When blended or compounded, it can better interact and disperse with the epoxy vinyl ester resin, forming a uniform system, increasing adhesion to the substrate, and improving the overall performance of the composite flexible vinyl ester resin as a coating resin.

[0008] In a second aspect, the present application further provides a method for preparing the cardanol-based vinyl resin modifier, comprising the following steps: (1) taking cardanol, adding catalyst 1 and a co-catalyst, heating to 200-270° C. under inert gas protection, and reacting for 3-8 h to obtain a crude cyclized dimer, which is then separated and purified by molecular distillation to obtain a cardanol dimer; (2) Add epichlorohydrin and catalyst 2 to the cardanol dimer at 70-100° C. for 3-6 h, then slowly add sodium hydroxide solution dropwise for 3-5 h while maintaining the temperature. After the addition is complete, continue the reaction for 0.5-2 h, cool to 50-60° C., add deionized water, stir, and allow to stand for stratification to obtain an epoxidized intermediate; (3) The epoxidation intermediate is added with acrylic acid, catalyst 3 and a polymerization inhibitor to carry out ring-opening esterification at 70-90° C. for 20-24 h, and post-processed to obtain a cardanol-based vinyl resin modifier.

[0009] Specifically, the catalyst 2 includes at least one of tetrabutylammonium bromide, triethylbenzylammonium chloride, and triphenylphosphine.

[0010] By adopting the above technical solution, a long-chain flexible functional group and a cycloolefin structure are constructed by forming a cardanol dimer, providing a basic flexible skeleton for the target product. The subsequent reaction retains this flexible long chain, and the reactive site is constructed by introducing a polar short-chain epoxy group. Then, by adding acrylic acid, the reaction conditions are controlled to cause a ring-opening esterification reaction, precisely introducing ester groups and ether bonds. The presence of ester groups and ether bonds not only further enhances the flexibility of the molecular chain, but also gives the product good adhesion and corrosion resistance. In addition, Catalyst 2 can significantly reduce the activation energy of the reaction by selecting a quaternary ammonium salt or phosphine catalyst, accelerating the process of the ring-opening etherification reaction, increasing the reaction rate, and shortening the reaction cycle.

[0011] The co-catalyst is one or more of CuCl2, KOH, FeCl3, and LiCl.

[0012] The mass ratio of the epoxidation intermediate to acrylic acid is (1.5-2):1.

[0013] The stoichiometric relationship within the mass ratio range of this application enables the cardanol-based vinyl resin modifier to form a well-structured, high-performance structure, with uniform distribution of ester and ether bonds within the molecular chain, ensuring the molecular chain has appropriate length and flexibility. Excessive epoxidation intermediates may lead to side reactions such as self-polymerization between epoxy groups, reducing the purity and yield of the target product. Furthermore, the presence of byproducts may reduce the flexibility of the cardanol-based vinyl resin modifier.

[0014] The catalyst 3 is at least one of N,N-dimethylbenzylamine and triphenylphosphine.

[0015] Preferably, the catalyst is N,N-dimethylbenzylamine.

[0016] By adopting the above technical solution, during the ring-opening esterification process, Catalyst 3 can direct the reaction toward the target product, effectively suppressing the occurrence of side reactions. This avoids other unnecessary reactions of the epoxy group and side reactions such as self-polymerization of acrylic compounds, resulting in higher product purity and ensuring the performance stability of the final product. The presence of the benzyl group and two methyl groups in N,N-dimethylbenzylamine makes its electron cloud distribution conducive to interaction with the reactant molecules, more effectively activating the epoxy and carboxyl groups, further accelerating the rate of the ring-opening esterification reaction, and making the formation of ester and ether bonds more regular. The arrangement of the molecular chains is more conducive to the flexible role of the long-chain alkyl groups, thereby greatly enhancing the flexibility of the resin and being environmentally friendly.

[0017] The polymerization inhibitor is one or both of p-hydroxyanisole and hydroquinone.

[0018] Preferably, the polymerization inhibitor comprises p-hydroxyanisole and hydroquinone, and the mass ratio of the p-hydroxyanisole to hydroquinone is (0.8-1):1.

[0019] By adopting the above technical solution, p-hydroxyanisole and hydroquinone can react rapidly with the free radicals generated in the reaction system to form stable compounds, prevent the vinyl group from self-polymerizing, and ensure that the reaction proceeds smoothly according to the designed molecular structure; excessive p-hydroxyanisole will lead to excessive inhibition, making the reaction rate too slow, affecting the tensile strength, flexural strength and other properties of the product; excessive hydroquinone can easily trigger by-product reactions, affecting purity and flexibility.

[0020] On the other hand, the present application also provides a flexible vinyl ester resin composition, which includes a cardanol-based vinyl resin modifier, modified silicon nanoparticles and epoxy vinyl ester resin.

[0021] The mass ratio of the cardanol-based vinyl resin modifier, the modified silicon nanoparticles and the epoxy vinyl ester resin is (0.1-0.3): (0.01-0.1):1.

[0022] Preparation of modified silicon nanoparticles: Add ethyl orthosilicate to an ethanol aqueous solution containing ammonia water, react at 25°C for 1-3 hours, heat to 55-65°C, stir for 2-4 hours, and then centrifuge for 10-20 minutes after the product gradually aggregates. Discard the supernatant, wash three times with anhydrous ethanol, and vacuum dry to obtain silicon nanoparticles. Take the silicon nanoparticles obtained above and add an ethanol aqueous solution containing KH-570, and react at 75-85°C for 1-3 hours to obtain modified silicon nanoparticles.

[0023] By adopting the above technical solution, the cardanol-based vinyl resin modifier has a flexible structure such as chain alkyl, ether bond, and ester group. When it is mixed with epoxy vinyl ester resin, the long-chain alkyl group can be inserted between the molecular chains of the epoxy vinyl ester resin, and the ether bond and ester bond further enhance the internal rotational freedom of the epoxy vinyl ester resin, increasing the flexibility and bendability of the molecular chain. By dispersing stress through its own deformation, the combined effect improves the anti-brittle fracture performance and crack resistance, making the flexible vinyl ester resin have excellent flexibility and impact resistance. The addition of lower modulus modified nano-silicon particles allows the modified nano-silicon particles to deform and move relatively easily in the vinyl ester resin. The ester bond in the modified molecule also has high flexibility. The modification improves its dispersibility and fully disperses in the resin matrix to enhance flexibility. In addition, the KH570-modified nano-silicon particles and the modifier have similar groups, high adaptability, and good compatibility with the resin, which facilitates the combined effect of the nano-silicon particles and the modifier to achieve unexpected high flexibility. When the vinyl ester resin is impacted by an external force, the nano silicon particles can absorb and dissipate energy through their own deformation and the movement of the molecular chain, thereby coordinating the effect of multiple flexible groups of the modifier to further improve the toughness and impact resistance of the resin. The suitable mass ratio of the present application can make the cardanol-based vinyl resin modifier, modified silicon nanoparticles and epoxy vinyl ester resin interact with each other to form a uniform, dense and quite elastic cross-linked network structure, which can not only ensure the mechanical properties of the composite flexible vinyl ester resin, but also provide good flexibility. Excessive modifiers can cause the flexibility of the resin to increase excessively, while properties such as strength, hardness and heat resistance can be reduced. Excessive modified silicon nanoparticles can also reduce flexibility.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. The present invention has a modifier with the above structure that has good performance in improving the brittle fracture of epoxy vinyl ester resin. This may be due to the long-chain alkyl contained in the cardanol-based vinyl resin modifier, which has good flexibility and rotatability, giving the resin excellent flexibility. The cardanol-based vinyl resin modifier also has a unique cyclic unsaturated cycloolefin structure. Compared with the straight chain and saturated cyclic structure, the rotation and twisting of the molecular chain are easier, which effectively improves the flexibility and elasticity of the cardanol-based vinyl resin modifier. In addition, the ether bond has a certain degree of internal rotation freedom; the molecular chain can move more flexibly, and the presence of the ester bond also gives the molecular chain a certain flexibility and bendability, thereby ensuring the flexibility of the resin. In addition, the flexible structure in the cardanol-based vinyl resin modifier can penetrate into the molecular chains of the epoxy vinyl ester resin, increase the mobility of the molecular chain, improve the flexibility of the epoxy vinyl ester resin, reduce the brittleness of the resin after curing, and improve its impact resistance and crack resistance; improve the comprehensive performance of the flexible vinyl ester resin composition as a coating resin.

[0025] 2. The stoichiometric relationship within the mass ratio range of this application results in a cardanol-based vinyl resin modifier with a well-organized structure and excellent performance, with ester and ether bonds evenly distributed throughout the molecular chain, ensuring the molecular chain has appropriate length and flexibility. Excessive epoxidation intermediates may lead to side reactions such as self-polymerization between epoxy groups, reducing the purity and yield of the target product. Furthermore, the presence of byproducts may reduce the flexibility of the cardanol-based vinyl resin modifier.

[0026] 3. The selection of the polymerization inhibitor in the present application enables p-hydroxyanisole and hydroquinone to react rapidly with the free radicals generated in the reaction system to form a stable compound, thereby preventing vinyl self-polymerization and ensuring the smooth progress of the reaction; among them, excessive p-hydroxyanisole will lead to excessive inhibition, slowing the reaction rate, and insufficient cross-linking, affecting the tensile and bending properties of the product; excessive hydroquinone is likely to induce by-product reactions, affecting purity and flexibility. DETAILED DESCRIPTION

[0027] In this application, epichlorohydrin was purchased from Shandong Haideng New Materials Co., Ltd.; tetraethylammonium bromide was purchased from Maclean; cardanol was purchased from Changshu Naisu Biomaterials Technology Co., Ltd.; catalyst 1 was activated clay purchased from Jinan Huisheng Chemical Co., Ltd.; sodium hydroxide solution was a 10% by mass sodium hydroxide solution; hydrochloric acid was a 5% by mass hydrochloric acid; acrylic acid was purchased from Shandong Shengbang International Trade Co., Ltd.; epoxy vinyl ester resin model: Derakane 411. All other raw materials were commercially available.

[0028] Preparation Example 1 Preparation of modified silicon nanoparticles: 1 mol of ethyl orthosilicate was slowly added dropwise to a 2 L ethanol-water solution containing 3 mol of ammonia. After the reaction was completed at 25°C with magnetic stirring for 2 hours, the reaction system was transferred to a thermostatic water bath, heated to 60°C, stirred for 3 hours, and centrifuged at 8000 / min for 15 minutes. The supernatant was discarded, washed three times with anhydrous ethanol, and dried under vacuum at 60°C for 12 hours to obtain silicon nanoparticles. The silicon nanoparticles obtained above were added to an ethanol-water solution containing 10% by mass of KH-570. The reaction was continued at 80°C for 2 hours. The modified silicon nanoparticles were then filtered, washed, and dried.

[0029] Preparation Example 2 Preparation of modified silicon nanoparticles: 1 mol of ethyl orthosilicate was slowly added dropwise to a 2 L ethanol-water solution containing 3 mol of ammonia. After the reaction was completed at 25°C with magnetic stirring for 2 hours, the reaction system was transferred to a thermostatic water bath, heated to 60°C, stirred for 3 hours, and centrifuged at 8000 / min for 15 minutes. The supernatant was discarded, washed three times with anhydrous ethanol, and dried under vacuum at 60°C for 12 hours to obtain silicon nanoparticles. The silicon nanoparticles obtained above were added to an ethanol-water solution containing 10% by mass of KH-550. The reaction was continued at 80°C for 2 hours. The modified silicon nanoparticles were then filtered, washed, and dried.

[0030] Example 1 The preparation method of a cardanol-based vinyl resin modifier comprises the following steps: adding 300 g of cardanol, 30 g of activated clay, and 0.3 g of copper chloride to a four-necked reaction flask, stirring for 10 minutes, heating to 200° C. and reacting for 7 hours, cooling to 70° C., adding 200 g of anhydrous ethanol, stirring for 1 hour, adding hydrochloric acid for neutralization, filtering, heating the material to 80° C., vacuuming and discharging, and then distilling out the unreacted cardanol monomer at a temperature of 195° C. and a vacuum degree of 10 Pa to obtain a cardanol dimer; Take 150g of cardanol dimer, add 350g of epichlorohydrin and 0.75g of tetrabutylammonium bromide, react at 80°C for 3h, maintain the temperature, slowly add sodium hydroxide solution dropwise for 3h, continue to react for 1h after the addition is complete, cool to 50°C, add 100g of deionized water, stir for 15min, let stand for 1h, separate the water layer, and obtain the epoxidation intermediate; Take 200g of the epoxidation intermediate, add 110g of acrylic acid, 2g of dimethylbenzylamine, 0.5g of p-hydroxyanisole and 0.5g of hydroquinone, react at 90°C for 24h, cool to 35°C, add potassium carbonate, stir for 2h, then add 100g of water and 200g of dichloromethane, stir for 30min, let stand for 1h to separate the water layer, and concentrate in vacuo at 30°C to obtain the final product, cardanol-based vinyl resin modifier.

[0031] Example 2 The preparation method of a cardanol-based vinyl resin modifier comprises the following steps: adding 300 g of cardanol, 30 g of activated clay, and 0.3 g of FeCl3 into a four-necked reaction flask, stirring for 10 min, heating to 200° C. and reacting for 7 h, cooling to 70° C., adding 200 g of anhydrous ethanol, stirring for 1 h, adding hydrochloric acid for neutralization, filtering, heating the material to 80° C., vacuuming and discharging, and then distilling out the unreacted cardanol monomer at a temperature of 195° C. and a vacuum degree of 10 Pa to obtain a cardanol dimer; Take 150g of cardanol dimer, add 350g of epichlorohydrin and 0.75g of tetrabutylammonium bromide, react at 80°C for 3h, maintain the temperature, slowly add sodium hydroxide solution dropwise for 3h, continue to react for 1h after the addition is complete, cool to 50°C, add 100g of deionized water, stir for 15min, let stand for 1h, separate the water layer, and obtain the epoxidation intermediate; Take 186g of the epoxidized intermediate, add 124g of acrylic acid, 2g of dimethylbenzylamine, 0.5g of p-hydroxyanisole and 0.5g of hydroquinone, react at 90°C for 24h, cool to 35°C, add potassium carbonate, stir for 2h, then add 100g of water and 200g of dichloromethane, stir for 30min, let stand for 1h to remove the water layer, and concentrate in vacuo at 30°C to obtain the final product, cardanol-based vinyl resin modifier.

[0032] Example 3 The preparation method of a cardanol-based vinyl resin modifier comprises the following steps: adding 300 g of cardanol, 30 g of activated clay, and 0.3 g of KOH into a four-necked reaction flask, stirring for 10 minutes, heating to 200° C. and reacting for 7 hours, cooling to 70° C., adding 200 g of anhydrous ethanol, stirring for 1 hour, adding hydrochloric acid for neutralization, filtering, heating the material to 80° C., vacuuming and discharging, and then distilling out the unreacted cardanol monomer at a temperature of 195° C. and a vacuum degree of 10 Pa to obtain a cardanol dimer; Take 150g of cardanol dimer, add 350g of epichlorohydrin and 0.75g of triethylbenzylammonium chloride, react at 80°C for 3h, maintain the temperature, slowly add sodium hydroxide solution dropwise for 3h, continue to react for 1h after the addition is complete, cool to 50°C, add 100g of deionized water, stir for 15min, let stand for 1h, separate the water layer, and obtain the epoxidation intermediate; Take 200g of the epoxidation intermediate, add 110g of acrylic acid, 2g of dimethylbenzylamine, 0.5g of p-hydroxyanisole and 0.5g of hydroquinone, react at 90°C for 24h, cool to 35°C, add potassium carbonate, stir for 2h, then add 100g of water and 200g of dichloromethane, stir for 30min, let stand for 1h to separate the water layer, and concentrate in vacuo at 30°C to obtain the final product, cardanol-based vinyl resin modifier.

[0033] Example 4 The preparation method of a cardanol-based vinyl resin modifier comprises the following steps: adding 300 g of cardanol, 30 g of activated clay, and 0.3 g of KOH into a four-necked reaction flask, stirring for 10 minutes, heating to 200° C. and reacting for 7 hours, cooling to 70° C., adding 200 g of anhydrous ethanol, stirring for 1 hour, adding hydrochloric acid for neutralization, filtering, heating the material to 80° C., vacuuming and discharging, and then distilling out the unreacted cardanol monomer at a temperature of 195° C. and a vacuum degree of 10 Pa to obtain a cardanol dimer; Take 150g of cardanol dimer, add 350g of epichlorohydrin and 0.75g of triphenylphosphine, react at 80°C for 3h, maintain the temperature, slowly add sodium hydroxide solution dropwise for 3h, continue to react for 1h after the addition is complete, cool to 50°C, add 100g of deionized water, stir for 15min, let stand for 1h, separate the water layer, and obtain the epoxidized intermediate; Take 200g of the epoxidation intermediate, add 110g of acrylic acid, 2g of dimethylbenzylamine, 0.5g of p-hydroxyanisole and 0.5g of hydroquinone, react at 90°C for 24h, cool to 35°C, add potassium carbonate, stir for 2h, then add 100g of water and 200g of dichloromethane, stir for 30min, let stand for 1h to separate the water layer, and concentrate in vacuo at 30°C to obtain the final product, cardanol-based vinyl resin modifier.

[0034] Example 5 The preparation method of a cardanol-based vinyl resin modifier comprises the following steps: adding 300 g of cardanol, 30 g of activated clay, and 0.3 g of KOH into a four-necked reaction flask, stirring for 10 minutes, heating to 200° C. and reacting for 7 hours, cooling to 70° C., adding 200 g of anhydrous ethanol, stirring for 1 hour, adding hydrochloric acid for neutralization, filtering, heating the material to 80° C., vacuuming and discharging, and then distilling out the unreacted cardanol monomer at a temperature of 195° C. and a vacuum degree of 10 Pa to obtain a cardanol dimer; Take 150g of cardanol dimer, add 350g of epichlorohydrin and 0.75g of triethylbenzylammonium chloride, react at 80°C for 3h, maintain the temperature, slowly add sodium hydroxide solution dropwise for 3h, continue to react for 1h after the addition is complete, cool to 50°C, add 100g of deionized water, stir for 15min, let stand for 1h, separate the water layer, and obtain the epoxidation intermediate; Take 200g of the epoxidation intermediate, add 110g of acrylic acid, 2g of dimethylbenzylamine, 0.3g of p-hydroxyanisole and 0.7g of hydroquinone, react at 90°C for 24h, cool to 35°C, add potassium carbonate, stir for 2h, then add 100g of water and 200g of dichloromethane, stir for 30min, let stand for 1h to separate the water layer, and concentrate in vacuo at 30°C to obtain the final product, cardanol-based vinyl resin modifier.

[0035] Example 6 The preparation method of a cardanol-based vinyl resin modifier comprises the following steps: adding 300 g of cardanol, 30 g of activated clay, and 0.3 g of KOH into a four-necked reaction flask, stirring for 10 minutes, heating to 200° C. and reacting for 7 hours, cooling to 70° C., adding 200 g of anhydrous ethanol, stirring for 1 hour, adding hydrochloric acid for neutralization, filtering, heating the material to 80° C., vacuuming and discharging, and then distilling out the unreacted cardanol monomer at a temperature of 195° C. and a vacuum degree of 10 Pa to obtain a cardanol dimer; Take 150g of cardanol dimer, add 350g of epichlorohydrin and 0.75g of triethylbenzylammonium chloride, react at 80°C for 3h, maintain the temperature, slowly add sodium hydroxide solution dropwise for 3h, continue to react for 1h after the addition is complete, cool to 50°C, add 100g of deionized water, stir for 15min, let stand for 1h, separate the water layer, and obtain the epoxidation intermediate; Take 200g of the epoxidation intermediate, add 110g of acrylic acid, 2g of dimethylbenzylamine, and 1g of p-hydroxyanisole, react at 90°C for 24h, cool to 35°C, add potassium carbonate, stir for 2h, then add 100g of water and 200g of dichloromethane, stir for 30min, let stand for 1h to separate the water layer, and concentrate in vacuo at 30°C to obtain the final product, cardanol-based vinyl resin modifier.

[0036] Example 7 The preparation method of a cardanol-based vinyl resin modifier comprises the following steps: adding 300 g of cardanol, 30 g of activated clay, and 0.3 g of KOH into a four-necked reaction flask, stirring for 10 minutes, heating to 200° C. and reacting for 7 hours, cooling to 70° C., adding 200 g of anhydrous ethanol, stirring for 1 hour, adding hydrochloric acid for neutralization, filtering, heating the material to 80° C., vacuuming and discharging, and then distilling out the unreacted cardanol monomer at a temperature of 195° C. and a vacuum degree of 10 Pa to obtain a cardanol dimer; Take 150g of cardanol dimer, add 350g of epichlorohydrin and 0.75g of triethylbenzylammonium chloride, react at 80°C for 3h, maintain the temperature, slowly add sodium hydroxide solution dropwise for 3h, continue to react for 1h after the addition is complete, cool to 50°C, add 100g of deionized water, stir for 15min, let stand for 1h, separate the water layer, and obtain the epoxidation intermediate; Take 200g of the epoxidation intermediate, add 110g of acrylic acid, 2g of dimethylbenzylamine, and 1g of hydroquinone, react at 90°C for 24h, cool to 35°C, add potassium carbonate, stir for 2h, then add 100g of water and 200g of dichloromethane, stir for 30min, let stand for 1h to separate the water layer, and concentrate in vacuo at 30°C to obtain the final product, cardanol-based vinyl resin modifier.

[0037] Example 8 The preparation method of a cardanol-based vinyl resin modifier comprises the following steps: adding 300 g of cardanol, 30 g of activated clay, and 0.3 g of KOH into a four-necked reaction flask, stirring for 10 minutes, heating to 200° C. and reacting for 7 hours, cooling to 70° C., adding 200 g of anhydrous ethanol, stirring for 1 hour, adding hydrochloric acid for neutralization, filtering, heating the material to 80° C., vacuuming and discharging, and then distilling out the unreacted cardanol monomer at a temperature of 195° C. and a vacuum degree of 10 Pa to obtain a cardanol dimer; Take 150g of cardanol dimer, add 350g of epichlorohydrin and 0.75g of triethylbenzylammonium chloride, react at 80°C for 3h, maintain the temperature, slowly add sodium hydroxide solution dropwise for 3h, continue to react for 1h after the addition is complete, cool to 50°C, add 100g of deionized water, stir for 15min, let stand for 1h, separate the water layer, and obtain the epoxidation intermediate; Take 218g of the epoxidation intermediate, add 92g of acrylic acid, 2g of dimethylbenzylamine, 0.5g of p-hydroxyanisole and 0.5g of hydroquinone, react at 90°C for 24h, cool to 35°C, add potassium carbonate, stir for 2h, then add 100g of water and 200g of dichloromethane, stir for 30min, let stand for 1h to separate the water layer, and concentrate in vacuo at 30°C to obtain the final product, cardanol-based vinyl resin modifier.

[0038] Example 9 The cardanol-based vinyl resin modifier prepared in Example 3 was added to 100 g of epoxy vinyl ester resin, and the modified silicon nanoparticles prepared in Preparation Example 1 were added so that the mass ratio of epoxy vinyl ester resin, cardanol-based vinyl resin modifier and modified silicon nanoparticles was 1:0.2:0.05. The mixture was stirred at 200 r / min for 20 min, then heated to 60°C, stirred at 500 r / min for 60 min, vacuum degassed at -0.08 MPa, cooled and discharged to obtain a flexible epoxy vinyl ester resin composition.

[0039] Example 10 The cardanol-based vinyl resin modifier prepared in Example 3 was added to 100 g of epoxy vinyl ester resin, and the modified silicon nanoparticles prepared in Preparation Example 1 were added so that the mass ratio of epoxy vinyl ester resin, cardanol-based vinyl resin modifier and modified silicon nanoparticles was 1:0.24:0.01. The mixture was stirred at 200 r / min for 20 min, then heated to 60°C, stirred at 500 r / min for 60 min, vacuum degassed at -0.08 MPa, cooled and discharged to obtain a flexible epoxy vinyl ester resin composition.

[0040] Example 11 The cardanol-based vinyl resin modifier prepared in Example 3 was added to 100 g of epoxy vinyl ester resin, and the modified silicon nanoparticles prepared in Preparation Example 1 were added so that the mass ratio of epoxy vinyl ester resin, cardanol-based vinyl resin modifier and modified silicon nanoparticles was 1:0.05:0.2. The mixture was stirred at 200 r / min for 20 min, then heated to 60° C., stirred at 500 r / min for 60 min, vacuum degassed at -0.08 MPa, cooled and discharged to obtain a flexible epoxy vinyl ester resin composition.

[0041] Example 12 The cardanol-based vinyl resin modifier prepared in Example 3 was added to 100 g of epoxy vinyl ester resin, and the modified silicon nanoparticles prepared in Preparation Example 2 were added so that the mass ratio of epoxy vinyl ester resin, cardanol-based vinyl resin modifier and modified silicon nanoparticles was 1:0.05:0.2. The mixture was stirred at 200 r / min for 20 min, then heated to 60°C, stirred at 500 r / min for 60 min, vacuum degassed at -0.08 MPa, cooled and discharged to obtain a flexible epoxy vinyl ester resin composition.

[0042] Example 13 To 100 g of epoxy vinyl ester resin, the modified silicon nanoparticles prepared in Preparation Example 1 were added so that the mass ratio of epoxy vinyl ester resin to modified silicon nanoparticles was 1:0.25. The mixture was stirred at 200 rpm for 20 min, then heated to 60° C., stirred at 500 rpm for 60 min, vacuum degassed at -0.08 MPa, and cooled to obtain a flexible epoxy vinyl ester resin composition.

[0043] Performance testing In Examples 1-8, 100g of a resin mixture was prepared using a 1:0.25 ratio of epoxy vinyl ester resin (Derakane 411): modifier. 3.5g of cumene hydroperoxide was added to 100g of the resin mixture from Examples 9-13, respectively. The mixture was poured into a mold, placed in a vacuum oven for vacuum degassing, and then baked at 150°C for 1 hour. The molded bars were then demolded to produce the following dimensions: length L = 80 ± 2mm, width b = 10.0 ± 0.2mm, thickness h = 4.0 ± 0.2mm. Testing was performed for tensile strength, tensile modulus, and elongation according to GB / T 1040; and for flexural strength and flexural modulus according to GB9341. Comparative test results are as follows: Table 1 Performance test results As shown in Table 1, the flexible epoxy vinyl ester resin composition of the present application has certain flexibility and bendability, comprehensive properties such as anti-brittle fracture performance and anti-cracking performance, is conducive to the high-performance application of vinyl resin, and can achieve excellent comprehensive effect. Wherein embodiment 3 and embodiment 5-7 can be seen that the polymerization inhibitor is p-hydroxyanisole and hydroquinone composite, which enhances the strength and flexibility of the cardanol-based vinyl resin modifier, can react rapidly with the free radicals produced in the reaction system to form a stable compound, prevent vinyl from self-polymerization, and ensure that the reaction proceeds smoothly; an excessive amount of p-hydroxyanisole can cause the inhibition to be too strong, make the reaction rate too slow, make the cross-linking degree insufficient, and affect the performance such as product stretching and bending; an excessive amount of hydroquinone easily causes by-product reaction, affecting purity and flexibility.

[0044] As can be seen from Examples 3 and 8, by using a specific mass ratio of epoxidation intermediates to acrylic acid, the present application enables the cardanol-based vinyl resin modifier to form a resin modifier with a regular structure and excellent performance, uniformly distributing ester and ether bonds in the molecular chain, and ensuring that the molecular chain has appropriate length and flexibility. Excessive epoxidation intermediates may cause side reactions such as self-polymerization between epoxy groups. The presence of byproducts may reduce the flexibility of the cardanol-based vinyl resin modifier, thereby reducing the flexibility of the flexible vinyl ester resin composition.

[0045] It can be seen from Examples 3 and 9 to 13 that the flexible vinyl ester resin prepared by mixing the cardanol-based vinyl resin modifier, modified silicon nanoparticles and epoxy vinyl ester resin of the present application takes into account both mechanical properties and elastic properties, effectively improving the problem of brittle fracture of vinyl epoxy resin.

[0046] As can be seen from Example 3 and Comparative Example 1, the flexible vinyl ester resin composition modified with the cardanol-based vinyl resin modifier has better flexibility than Derakane 411, can better balance the hardness and elasticity, has the comprehensive performance of strengthening and toughening, and is suitable for high-performance applications of vinyl ester resin.

[0047] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A cardanol-based vinyl resin modifier, characterized in that: Its structural formula is as shown in Formula I: In formula I, R is one of CH3CH2- or -CH=CH2.

2. A method for preparing the cardanol-based vinyl resin modifier according to claim 1, characterized in that: The steps include: (1) taking cardanol, adding catalyst 1 and a co-catalyst, heating to 200-270° C. under inert gas protection, and reacting for 3-8 h to obtain a crude cyclized dimer, which is then separated and purified by molecular distillation to obtain a cardanol dimer; (2) Add epichlorohydrin and catalyst 2 to the cardanol dimer at 70-100° C. for 3-6 h, then slowly add sodium hydroxide solution dropwise for 3-5 h while maintaining the temperature. After the addition is complete, continue the reaction for 0.5-2 h, cool to 50-60° C., add deionized water, stir, and allow to stand for stratification to obtain an epoxidized intermediate; (3) The epoxidation intermediate is added with acrylic acid, catalyst 3 and a polymerization inhibitor to carry out ring-opening esterification at 70-90° C. for 20-24 h, and post-processed to obtain a cardanol-based vinyl resin modifier.

3. The method for preparing the cardanol-based vinyl resin modifier according to claim 2, wherein: The catalyst 2 includes at least one of tetrabutylammonium bromide, triethylbenzylammonium chloride, and triphenylphosphine.

4. The method for preparing the cardanol-based vinyl resin modifier according to claim 2, wherein: The mass ratio of the epoxidation intermediate to acrylic acid in (3) is (1.5-2):

1.

5. The method for preparing the cardanol-based vinyl resin modifier according to claim 2, wherein: The catalyst 3 includes at least one of N,N-dimethylbenzylamine and triphenylphosphine.

6. The method for preparing the cardanol-based vinyl resin modifier according to claim 2, wherein: The polymerization inhibitor is one or both of p-hydroxyanisole and hydroquinone.

7. A flexible vinyl ester resin composition, characterized in that The flexible vinyl ester resin comprises the cardanol-based vinyl resin modifier according to claim 1, modified silicon nanoparticles and epoxy vinyl ester resin.

8. The flexible vinyl ester resin composition according to claim 7, wherein: The mass ratio of the cardanol-based vinyl resin modifier, the modified silicon nanoparticles and the epoxy vinyl ester resin is (0.1-0.3): (0.01-0.1):1.

Images