Halogen-free flame-retardant vinyl ester resin, preparation method thereof and composite resin

Abstract

This invention belongs to the field of organic polymer compounds, particularly to the C08G59 / 00 field, and more specifically to a halogen-free flame-retardant vinyl ester resin, its preparation method, and a composite resin. The raw materials for preparing the composite resin include, by mass percentage, at least: 30-45% halogen-free flame-retardant vinyl ester resin, 40-50% high-temperature resistant vinyl ester resin, 0.02-0.05% secondary polymerization inhibitor, 10-20% crosslinkable monomer, and 0-20% additive flame retardant; wherein the raw materials for preparing the halogen-free flame-retardant vinyl ester resin include, by mass percentage, at least: 40-60% epoxy resin, 13-18% unsaturated monocarboxylic acid, 0.05-0.1% polymerization inhibitor, 0.5-0.7% catalyst, 24-35% crosslinking monomer, and 0.3-0.7% coupling agent. The composite resin provided by this invention is not only high-temperature resistant and halogen-free, but also has excellent mechanical properties, and the preparation process is simple and environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of organic polymer compounds, particularly to the field of C08G59 / 00, and more specifically to a halogen-free flame-retardant vinyl ester resin, its preparation method, and a composite resin. Background Technology

[0002] Vinyl ester resin is a thermosetting resin that is produced by using epoxy resin and unsaturated monocarboxylic acid containing double bonds as starting materials. Under the combined action of catalysts and other additives, a ring-opening esterification reaction is carried out upon heating to obtain oligomers with unsaturated double bonds at the end or side groups. These oligomers are then dissolved in crosslinking monomers to obtain a free-radical curable resin. Vinyl ester resin combines the excellent corrosion resistance and mechanical properties of epoxy resin with the convenient processing properties of unsaturated polyester resin, making it a major matrix material for corrosion-resistant fiberglass products. Its applications are widespread, spanning various sectors of the national economy, including chemical, metallurgical, and construction industries. However, due to the low oxygen index of vinyl ester epoxy resin, typically only 19.8%, it is highly flammable, making it unsuitable for special applications such as rail transportation and shipping. Furthermore, combustion releases large amounts of toxic gases, posing serious safety hazards. Research has found that adding flame retardants to the resin matrix can significantly improve its flame retardancy. The current mainstream solutions are as follows: 1) Dispersing additive flame retardants in polymer materials through physical blending to exert their flame-retardant effect; additive flame retardants are widely used due to their large dosage and ease of operation. However, they typically have poor solubility with the matrix and are prone to phase separation during the curing process, making it difficult to achieve a balance between flame retardancy and mechanical properties. 2) Incorporating flame-retardant elements into the reacting raw materials through molecular structure design or chemical modification. These elements participate in the polymerization reaction, thus binding to the main chain or side chain of the polymer to exert a flame-retardant effect. Reactive flame retardants are characterized by good flame-retardant stability, resistance to disappearance, and minimal impact on materials, but their operation and processing are more complex. Currently, many reactive flame-retardant resins on the market contain halogens, which are incompatible with halogen-free environmentally friendly flame-retardant technologies. However, with increasing environmental awareness, many countries around the world have banned the use of halogenated flame retardants because they release large amounts of corrosive and harmful gases during combustion. Meanwhile, traditional vinyl ester resins have insufficient high-temperature resistance, failing to meet the requirements of high-temperature applications and limiting their use. Therefore, developing a high-temperature resistant, halogen-free flame-retardant vinyl ester resin with a simple preparation process and easy industrialization is of great significance.

[0003] Existing technology, patent CN107383337A, discloses a halogen-free flame-retardant vinyl ester resin. Its preparation raw materials include phosphorus-containing epoxy resin, unsaturated monobasic acid, catalyst, polymerization inhibitor, and crosslinkable monomer. This vinyl ester resin does not produce toxic halogen-containing gases during combustion, thus solving the defect of deteriorated physical properties of composite materials. Existing technology CN111454463B discloses a flame-retardant phosphorylated carbon nanotube-modified acrylic resin material. Its preparation raw materials include phosphorylated carbon nanotubes, epoxy resin, styrene, methyl methacrylate, methacrylic acid, etc. This acrylic resin material not only solves the problem of poor raw material compatibility but also has good flame-retardant properties. However, the above inventions cannot simultaneously achieve strong flame retardancy, excellent mechanical properties, and low production costs. Summary of the Invention

[0004] To address the aforementioned problems, the first aspect of this invention provides a halogen-free flame-retardant vinyl ester resin, wherein the raw materials for preparation include, by mass percentage, at least: 40-60% epoxy resin, 13-18% unsaturated monocarboxylic acid, 0.05-0.1% polymerization inhibitor, 0.5-0.7% catalyst, 24-35% crosslinking monomer, and 0.3-0.7% coupling agent.

[0005] Preferably, the epoxy resin includes at least one of halogen-free flame-retardant epoxy resin, phenol-biphenyl epoxy resin, phenol-aromatic epoxy resin, and dicyclopentadiene-phenol epoxy resin.

[0006] More preferably, the epoxy resin includes at least one of phenol-biphenyl epoxy resin, dicyclopentadiene-phenol epoxy resin, and halogen-free flame-retardant epoxy resin.

[0007] Preferably, the unsaturated monocarboxylic acid includes at least one of methacrylic acid, acrylic acid, and butenoic acid.

[0008] More preferably, the unsaturated monocarboxylic acid includes at least one of acrylic acid and methacrylic acid.

[0009] Preferably, the polymerization inhibitor includes at least one or more of tert-butylhydroquinone, 4-tert-butylcatechol, p-benzoquinone, hydroquinone, methyl hydroquinone, and p-hydroxyanisole.

[0010] More preferably, the polymerization inhibitor includes p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone.

[0011] More preferably, the mass ratio of p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone is (3-6):(0.1-3):(0.5-4).

[0012] As an feasible approach, the mass ratio of p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone may include 5.2:0.7:3.8, 5:0.7:3.7, 3.8:2.7:0.6, or 3.7:2.6:0.6.

[0013] Preferably, the catalyst comprises at least one or more of trimethylamine, methyl sulfide, diethylene glycol dimethyl ether, triphenylphosphine, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyldimethylamine, imidazole, 1-methylimidazolium, 2-ethyl-4-methylimidazolium, and 2-heptadecylimidazolium.

[0014] More preferably, the catalyst includes at least triphenylphosphine and benzyltrimethylammonium chloride.

[0015] More preferably, the mass ratio of the triphenylphosphine to benzyltrimethylammonium chloride is (1-3):(4-6).

[0016] As an implementable example, the mass ratio of triphenylphosphine to benzyltrimethylammonium chloride may include 2:5.9, 1.94:5.8, 1.5:4.4, or 1.5:4.3.

[0017] Preferably, the crosslinking monomer includes at least one or more of styrene, vinyltoluene, divinylbenzene, diallyl phthalate, TAIC, methyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and neopentyl glycol dimethacrylate.

[0018] More preferably, the crosslinking monomer includes at least styrene.

[0019] Preferably, the coupling agent comprises at least one or more of methyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, maleic anamidopropyltriethoxysilane, and aminoethylaminopropyltrimethoxysilane.

[0020] More preferably, the coupling agent includes at least γ-(methacryloyloxy)propyltrimethoxysilane.

[0021] This invention utilizes specific raw materials to prepare a halogen-free flame-retardant vinyl ester resin. The main polymer components include epoxy resin, unsaturated monocarboxylic acid, and crosslinking monomers. The epoxy resin and the unsaturated monocarboxylic acid containing double bonds are used as starting materials. Under the combined action of catalysts and other additives, a ring-opening esterification reaction is performed by heating to obtain oligomers with unsaturated double bonds at the end or side groups. These oligomers are then dissolved in the crosslinking monomers to obtain a free-radical curable thermosetting resin. This resin combines the excellent corrosion resistance and mechanical properties of epoxy resin with the convenient processing properties of unsaturated polyester resin. The crosslinking monomers include at least styrene. Styrene is relatively reactive and can polymerize at room temperature, so it is difficult to effectively inhibit polymerization using a single-component polymerization inhibitor. p-hydroxyanisole is a commonly used polymerization inhibitor for acrylic acid and its ester monomers. It can effectively capture free radicals and thus prevent free radical chain reactions. Its advantage is that monomers that have not had the polymerization inhibitor removed can still participate in polymerization, and the effect on the polymerization reaction is not significant. The polymerization inhibition effect of polyphenols is actually an antioxidant effect. They are easily oxidized to quinone-type phenols, such as hydroquinone, which has high reactivity with peroxide free radicals and high polymerization inhibition activity. Benzene rings with electron-donating groups, such as 4-tert-butylcatechol, have high reactivity with peroxide free radicals and strong polymerization inhibition activity. Tert-butylcatechol has a very poor polymerization inhibition effect at high temperatures, but at slightly lower temperatures, its polymerization inhibition effect is 25 times higher than that of hydroquinone. This invention selects polyphenolic polymerization inhibitors 4-tert-butylcatechol, hydroquinone, and p-hydroxyanisole in a compound. When the mass ratio of p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone is (3-6):(0.1-3):(0.5-4), it not only achieves better polymerization inhibition but also does not affect other reactions. It also has a polymerization inhibition effect at high temperatures. The polymerization inhibition effect of the compounded inhibitors is about 300 times that of the single inhibitor. By using this specific polymerization inhibitor, a halogen-free flame-retardant vinyl ester resin with a suitable molecular weight can be obtained. The oxygen index of this resin can reach more than 32%. When used as a raw material for the preparation of composite resins, it can provide excellent flame-retardant properties for composite resins.

[0022] A second aspect of this invention provides a method for preparing a halogen-free flame-retardant vinyl ester resin, comprising the following steps:

[0023] Epoxy resin is added to a reactor and kept at 80±2℃ with stirring until melted. Unsaturated monocarboxylic acid and polymerization inhibitor are then added, and the mixture is kept at 80±2℃ with stirring for 0.3-0.8 hours. After stirring, a catalyst is added, and cooling water is turned on. The reactor temperature is controlled at 18-22℃ / h, and the final reactor temperature reaches 115±2℃. When the temperature reaches 105-110℃, the epoxy value and acid value are tested every 0.3-0.8 hours. The reaction endpoint is reached when the epoxy value is less than 0.02mol / 100g and the acid value is less than 14mgKOH / g. The temperature is then lowered to 75-85℃, and polymerization inhibitor, crosslinking monomer, and coupling agent are added according to the mass ratio. Stirring continues for 0.5-1.0 hours to obtain halogen-free flame-retardant vinyl ester resin.

[0024] The third aspect of the present invention provides a composite resin, wherein the raw materials for preparing the composite resin include, by weight percentage, at least: 30-45% halogen-free flame-retardant vinyl ester resin, 40-50% high-temperature resistant vinyl ester resin, 0.02-0.05% second polymerization inhibitor, 10-20% crosslinkable monomer, and 0-20% additive flame retardant.

[0025] Preferably, the second polymerization inhibitor comprises at least one of hydroquinone, 4-tert-butylcatechol, 4-hydroxy-2,2,6,6-tetramethylpiperidine oxide, p-benzoquinone, p-hydroxyanisole, and o-methylhydroquinone.

[0026] More preferably, the second polymerization inhibitor includes at least o-methylhydroquinone.

[0027] Preferably, the crosslinkable monomer includes at least one of styrene, trimethylolpropane triacrylate, tri(methacrylate)trimethylolpropane, pentaerythritol triacrylate, and dipentaerythritol hexaacrylate.

[0028] More preferably, the crosslinkable monomers are pentaerythritol triacrylate and trimethylolpropane triacrylate.

[0029] Preferably, the additive flame retardant includes at least one of antimony trioxide, aluminum hydroxide, magnesium hydroxide, ammonium polyphosphate, dimethyl methyl phosphate, triphenyl phosphate, and DOPO.

[0030] As an example of implementation, the additive flame retardant may include aluminum hydroxide.

[0031] The method for preparing the composite resin includes mixing the raw materials evenly.

[0032] The composite resin prepared by this invention is obtained by crosslinking halogen-free flame-retardant vinyl ester resin and high-temperature resistant vinyl ester resin together. The halogen-free flame-retardant vinyl ester resin has an oxygen index of up to 32%. The resulting composite resin not only exhibits good flame retardancy with an oxygen index exceeding 28%, but also demonstrates high-temperature resistance, with a glass transition temperature (Tg) exceeding 190°C. Furthermore, the introduction of crosslinkable monomers further enhances the mechanical properties of the composite resin, resulting in a longer service life. The preparation method of the composite resin described in this invention is simple, requiring only uniform mixing of the raw materials, and avoids the use of organic solvents. This method not only achieves low-cost and high-efficiency preparation but is also environmentally friendly.

[0033] Beneficial effects

[0034] 1. The present invention synthesizes a halogen-free flame-retardant vinyl ester resin by following specific raw materials and their proportions. The oxygen index of the halogen-free flame-retardant vinyl ester resin can reach 32%. It can be blended with high-temperature resistant vinyl ester resin to prepare a composite resin. It not only has good flame retardant properties and an oxygen index of over 28%, but also has high temperature resistance, with a glass transition temperature (Tg) of over 190°C.

[0035] 2. The halogen-free flame-retardant vinyl ester resin prepared by the present invention has excellent flame-retardant effect, and its own oxygen index can reach 32%. Moreover, since it does not contain halogen elements, it will not produce toxic halogen-containing gases at high temperatures, and can be used in materials with high fire protection requirements.

[0036] 3. The composite resin prepared by this invention has a molecular formula that is completely free of halogens, making it more environmentally friendly than halogen-containing chemical flame-retardant vinyl ester resins on the market.

[0037] 4. The composite resin prepared by the present invention has excellent heat resistance and flame retardancy after compounding, while its mechanical properties and corrosion resistance do not decrease significantly.

[0038] 5. The composite resin prepared by this invention has a moderate viscosity and is suitable for composite material molding processes such as hand lay-up, vacuum induction, resin transfer molding (RTM), and pultrusion. It also has good wetting properties with carbon fiber or glass fiber.

[0039] 6. The composite resin production process described in this invention is simple and low-cost, easy to industrialize, and the preparation process is relatively green and environmentally friendly, avoiding the use of organic solvents, and has a good market promotion prospect. Attached Figure Description

[0040] Figure 1 The image shows the DSC curve of the halogen-free flame-retardant vinyl ester resin prepared in Example 1, where the oxygen index of the halogen-free flame-retardant vinyl ester resin alone is 32%.

[0041] Figure 2 The image shows the DSC curve of the composite resin prepared in Example 1.

[0042] Figure 3 The image shows the DSC curve of the composite resin prepared in Example 2.

[0043] Figure 4 The image shows the DSC curve of the composite resin prepared in Example 3.

[0044] Figure 5 The image shows the DSC curve of the composite resin prepared in Example 4.

[0045] Figure 6 The image shows the DSC curve of the composite resin prepared in Example 5.

[0046] Figure 7 The image shows the DSC curve of the composite resin prepared in Example 6.

[0047] Figure 8 The image shows the DSC curve of the composite resin prepared in Comparative Example 1.

[0048] Figure 9 The image shows the DSC curve of the composite resin prepared in Comparative Example 1. Detailed Implementation

[0049] Example 1

[0050] The first aspect of this embodiment provides a halogen-free flame-retardant vinyl ester resin, the raw materials of which, by mass percentage, are 56.8% epoxy resin, 16.9% unsaturated monocarboxylic acid, 0.086% polymerization inhibitor, 0.69% catalyst, 25% crosslinking monomer, and 0.524% coupling agent.

[0051] The epoxy resin mentioned is phenol-biphenyl epoxy resin SQXN-324 (purchased from Shandong Shengquan New Material Co., Ltd.).

[0052] The unsaturated monocarboxylic acid mentioned is methacrylic acid (CAS No.: 79-41-4).

[0053] The polymerization inhibitors are p-hydroxyanisole (CAS No.: 150-76-5), 4-tert-butylcatechol (CAS No.: 98-29-3), and hydroquinone (CAS No.: 123-31-9); the mass ratio of p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone is 5.2:0.7:3.8.

[0054] The catalyst is triphenylphosphine (CAS No.: 603-35-0) and benzyltrimethylammonium chloride (CAS No.: 56-93-9); the mass ratio of triphenylphosphine to benzyltrimethylammonium chloride is 2:5.9.

[0055] The crosslinking monomer is styrene (CAS No.: 100-42-5).

[0056] The coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane (CAS No.: 2530-85-0).

[0057] The second aspect of this embodiment provides a method for preparing a halogen-free flame-retardant vinyl ester resin, comprising the following steps:

[0058] Phenolic biphenyl epoxy resin was added to a reactor and heated to 80°C to melt it. Then, p-hydroxyanisole and 4-tert-butylcatechol were added, and the mixture was kept at 80°C and stirred for 10 minutes. Methacrylic acid was added, and after thorough stirring, triphenylphosphine and benzyltrimethylammonium chloride were added. Cooling water was turned on, and the reactor temperature was controlled at a rate of 20°C / h, until the final reactor temperature reached 115°C. Once the temperature reached 110°C, the epoxy value and acid value were tested every 0.5 hours. The reaction endpoint was reached when the epoxy value dropped to 0.021 eq / 100g and the acid value dropped to 14 mg KOH / g. The temperature was then lowered to 80°C, and hydroquinone, styrene, and γ-(methacryloyloxy)propyltrimethoxysilane were added. Stirring continued for 1.0 hour to obtain the halogen-free flame-retardant vinyl ester resin.

[0059] The third aspect of this embodiment provides a composite resin, the raw materials for preparing the composite resin being, by mass percentage: 34.99% halogen-free flame-retardant vinyl ester resin, 48.98% high-temperature resistant vinyl ester resin, 0.03% second polymerization inhibitor, and 16% crosslinkable monomer.

[0060] The second polymerization inhibitor is o-methylhydroquinone (CAS No.: 95-71-6).

[0061] The crosslinkable monomers are pentaerythritol triacrylate (CAS No.: 3524-68-3) and trimethylolpropane triacrylate (CAS No.: 15625-89-5), with a mass ratio of pentaerythritol triacrylate to trimethylolpropane triacrylate of 7.5:8.5.

[0062] The preparation method of the high-temperature resistant vinyl ester resin is as follows: 279.7 kg of phenolic epoxy resin SQPN-048 (purchased from Shandong Shengquan New Material Co., Ltd.) and 45.8 kg of multifunctional epoxy resin AG-80 (purchased from Shanghai Huayi Resin Co., Ltd.) are added to a reaction vessel, heated to 80℃ and melted, then 0.22 kg of p-hydroxyanisole (CAS No.: 150-76-5) is added, the temperature is maintained at 80±2℃, and stirred for 0.5 h, then 161.7 kg of methacrylic acid (CAS No.: 150-76-5) is added. 1.13 kg of triphenylphosphine (CAS No.: 603-35-0) and 4.14 kg of benzyltrimethylammonium chloride (CAS No.: 56-93-9) were added. The cooling water was turned on, and the heating rate of the reactor was controlled at 20℃ / h. The final reactor temperature reached 115℃. When the temperature reached 110℃, the epoxy value and acid value were tested every 0.5h. The reaction ended when the epoxy value dropped to 0.02eq / 100g and the acid value dropped to 14mgKOH / g, and the high-temperature resistant vinyl ester resin prepolymer was obtained. The mixture was cooled to 80℃, and 0.26 kg of 4-tert-butylcatechol (CAS No.: 98-29-3), 0.045 kg of hydroquinone (CAS No.: 123-31-9), 288.6 kg of styrene (CAS No.: 100-42-5), 150.9 kg of trimethylolpropane triacrylate (CAS No.: 15625-89-5), 47.4 kg of triallyl cyanurate (CAS No.: 101-37-1), and 5.0 kg of γ-(methacryloyloxy)propyltrimethoxysilane KH570 (CAS No.: 2530-85-0) were added. The mixture was stirred for 1.0 h to obtain a high-temperature resistant vinyl ester resin.

[0063] The composite resin is prepared by mixing the raw materials evenly.

[0064] The DSC curve of the halogen-free flame-retardant vinyl ester resin prepared in this embodiment is shown in the figure below. Figure 1 As shown, the oxygen index of the halogen-free flame-retardant vinyl ester resin alone is 32%.

[0065] The DSC curve of the composite resin prepared in this embodiment is shown in the figure below. Figure 2 As shown.

[0066] Example 2

[0067] The first aspect of this embodiment provides a halogen-free flame-retardant vinyl ester resin, the raw materials of which, by mass percentage, are 58.9% epoxy resin, 14.7% unsaturated monocarboxylic acid, 0.085% polymerization inhibitor, 0.70% catalyst, 25.16% crosslinking monomer, and 0.455% coupling agent.

[0068] The epoxy resin mentioned is phenol-biphenyl epoxy resin SQXN-324 (purchased from Shandong Shengquan New Material Co., Ltd.).

[0069] The unsaturated monocarboxylic acid mentioned is acrylic acid (CAS No.: 79-10-7).

[0070] The polymerization inhibitors are p-hydroxyanisole (CAS No.: 150-76-5), 4-tert-butylcatechol (CAS No.: 98-29-3), and hydroquinone (CAS No.: 123-31-9); the mass ratio of p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone is 5.0:0.7:3.7.

[0071] The catalyst is triphenylphosphine (CAS No.: 603-35-0) and benzyltrimethylammonium chloride (CAS No.: 56-93-9); the mass ratio of triphenylphosphine to benzyltrimethylammonium chloride is 1.94:5.8.

[0072] The crosslinking monomer is styrene (CAS No.: 100-42-5).

[0073] The coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane (CAS No.: 2530-85-0).

[0074] The second aspect of this embodiment provides a method for preparing a halogen-free flame-retardant vinyl ester resin, comprising the following steps:

[0075] Phenolic biphenyl epoxy resin was added to a reactor and heated to 80°C to melt it. Then, p-hydroxyanisole and 4-tert-butylcatechol were added, and the mixture was kept at 80°C and stirred for 10 minutes. Acrylic acid was added, and after thorough stirring, triphenylphosphine and benzyltrimethylammonium chloride were added. Cooling water was turned on, and the reactor temperature was controlled at a rate of 20°C / h, until the final reactor temperature reached 115°C. Starting at 110°C, the epoxy value and acid value were tested every 0.5 hours. The reaction endpoint was reached when the epoxy value dropped to 0.021 eq / 100g and the acid value dropped to 15 mg KOH / g. The temperature was then lowered to 80°C, and hydroquinone, styrene, and γ-(methacryloyloxy)propyltrimethoxysilane were added. Stirring continued for 1.0 hour to obtain the halogen-free flame-retardant vinyl ester resin.

[0076] The third aspect of this embodiment provides a composite resin, the raw materials for which are prepared as follows: 34.99% halogen-free flame-retardant vinyl ester resin, 48.98% high-temperature resistant vinyl ester resin, 0.03% second polymerization inhibitor, and 16% crosslinkable monomer.

[0077] The second polymerization inhibitor is o-methylhydroquinone (CAS No.: 95-71-6).

[0078] The crosslinkable monomers are pentaerythritol triacrylate (CAS No.: 3524-68-3), trimethylolpropane triacrylate (CAS No.: 15625-89-5), and pentaerythritol triacrylate in a mass ratio of 7.5:8.5.

[0079] The additive flame retardant is aluminum hydroxide (CAS No.: 21645-51-2).

[0080] The preparation method of the high-temperature resistant vinyl ester resin is as follows: 279.7 kg of phenolic epoxy resin SQPN-048 (purchased from Shandong Shengquan New Material Co., Ltd.) and 45.8 kg of multifunctional epoxy resin AG-80 (purchased from Shanghai Huayi Resin Co., Ltd.) are added to a reaction vessel, heated to 80℃ and melted, then 0.22 kg of p-hydroxyanisole (CAS No.: 150-76-5) is added, the temperature is maintained at 80±2℃, and stirred for 0.5 h, then 161.7 kg of methacrylic acid (CAS No.) is added. The reaction mixture consisted of 79-41-4), 1.13 kg of triphenylphosphine (CAS No.: 603-35-0), and 4.14 kg of benzyltrimethylammonium chloride (CAS No.: 56-93-9). Cooling water was turned on, and the heating rate of the reactor was controlled at 20℃ / h. The final reactor temperature reached 115℃. Starting from 110℃, the epoxy value and acid value were tested every 0.5h. The reaction endpoint was reached when the epoxy value dropped to 0.02eq / 100g and the acid value dropped to 14mgKOH / g, yielding a high-temperature resistant vinyl ester resin prepolymer. The mixture was cooled to 80℃, and 0.26 kg of 4-tert-butylcatechol (CAS No.: 98-29-3), 0.045 kg of hydroquinone (CAS No.: 123-31-9), 288.6 kg of styrene (CAS No.: 100-42-5), 150.9 kg of trimethylolpropane triacrylate (CAS No.: 15625-89-5), 47.4 kg of triallyl cyanurate (CAS No.: 101-37-1), and 5.0 kg of γ-(methacryloyloxy)propyltrimethoxysilane KH570 (CAS No.: 2530-85-0) were added. The mixture was stirred for 1.0 h to obtain a high-temperature resistant vinyl ester resin.

[0081] The composite resin is prepared by mixing the raw materials evenly.

[0082] The DSC curve of the composite resin prepared in this embodiment is shown in the figure below. Figure 3 As shown.

[0083] Example 3

[0084] The first aspect of this embodiment provides a halogen-free flame-retardant vinyl ester resin, the raw materials of which, by mass percentage, are 56.84% epoxy resin, 16.91% unsaturated monocarboxylic acid, 0.085% polymerization inhibitor, 0.69% catalyst, 24.98% crosslinking monomer, and 0.495% coupling agent.

[0085] The epoxy resin mentioned is phenol-biphenyl epoxy resin SQXN-324 (purchased from Shandong Shengquan New Material Co., Ltd.).

[0086] The unsaturated monocarboxylic acid mentioned is methacrylic acid (CAS No.: 79-41-4).

[0087] The polymerization inhibitors are p-hydroxyanisole (CAS No.: 150-76-5), 4-tert-butylcatechol (CAS No.: 98-29-3), and hydroquinone (CAS No.: 123-31-9); the mass ratio of p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone is 5.2:0.7:3.8.

[0088] The catalyst is triphenylphosphine (CAS No.: 603-35-0) and benzyltrimethylammonium chloride (CAS No.: 56-93-9); the mass ratio of triphenylphosphine to benzyltrimethylammonium chloride is 2:5.9.

[0089] The crosslinking monomer is styrene (CAS No.: 100-42-5).

[0090] The coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane (CAS No.: 2530-85-0).

[0091] The second aspect of this embodiment provides a method for preparing a halogen-free flame-retardant vinyl ester resin, comprising the following steps:

[0092] Phenolic biphenyl epoxy resin was added to a reactor and heated to 80°C to melt it. Then, p-hydroxyanisole and 4-tert-butylcatechol were added, and the mixture was kept at 80°C and stirred for 10 minutes. Methacrylic acid was added, and after thorough stirring, triphenylphosphine and benzyltrimethylammonium chloride were added. Cooling water was turned on, and the reactor temperature was controlled at a rate of 20°C / h, until the final reactor temperature reached 115°C. Once the temperature reached 110°C, the epoxy value and acid value were tested every 0.5 hours. The reaction endpoint was reached when the epoxy value dropped to 0.021 eq / 100g and the acid value dropped to 14 mg KOH / g. The temperature was then lowered to 80°C, and hydroquinone, styrene, and γ-(methacryloyloxy)propyltrimethoxysilane were added. Stirring continued for 1.0 hour to obtain the halogen-free flame-retardant vinyl ester resin.

[0093] The third aspect of this embodiment provides a composite resin, the raw materials for which are prepared as follows: 30% halogen-free flame-retardant vinyl ester resin, 44.97% high-temperature resistant vinyl ester resin, 0.03% second polymerization inhibitor, 15% crosslinkable monomer, and 10% additive flame retardant.

[0094] The second polymerization inhibitor is o-methylhydroquinone (CAS No.: 95-71-6).

[0095] The crosslinkable monomers are pentaerythritol triacrylate (CAS No.: 3524-68-3), trimethylolpropane triacrylate (CAS No.: 15625-89-5), and pentaerythritol triacrylate in a mass ratio of 7:8.

[0096] The additive flame retardant is aluminum hydroxide (model: ON-908) (CAS No.: 21645-51-2).

[0097] The preparation method of the high-temperature resistant vinyl ester resin is as follows: 279.7 kg of phenolic epoxy resin SQPN-048 (purchased from Shandong Shengquan New Material Co., Ltd.) and 45.8 kg of multifunctional epoxy resin AG-80 (purchased from Shanghai Huayi Resin Co., Ltd.) are added to a reaction vessel, heated to 80℃ and melted, then 0.22 kg of p-hydroxyanisole (CAS No.: 150-76-5) is added, the temperature is maintained at 80±2℃, and stirred for 0.5 h, then 161.7 kg of methacrylic acid (CAS No.) is added. The reaction mixture consisted of 79-41-4), 1.13 kg of triphenylphosphine (CAS No.: 603-35-0), and 4.14 kg of benzyltrimethylammonium chloride (CAS No.: 56-93-9). Cooling water was turned on, and the heating rate of the reactor was controlled at 20℃ / h. The final reactor temperature reached 115℃. Starting from 110℃, the epoxy value and acid value were tested every 0.5h. The reaction endpoint was reached when the epoxy value dropped to 0.02eq / 100g and the acid value dropped to 14mgKOH / g, yielding a high-temperature resistant vinyl ester resin prepolymer. The mixture was cooled to 80℃, and 0.26 kg of 4-tert-butylcatechol (CAS No.: 98-29-3), 0.045 kg of hydroquinone (CAS No.: 123-31-9), 288.6 kg of styrene (CAS No.: 100-42-5), 150.9 kg of trimethylolpropane triacrylate (CAS No.: 15625-89-5), 47.4 kg of triallyl cyanurate (CAS No.: 101-37-1), and 5.0 kg of γ-(methacryloyloxy)propyltrimethoxysilane KH570 (CAS No.: 2530-85-0) were added. The mixture was stirred for 1.0 h to obtain a high-temperature resistant vinyl ester resin.

[0098] The composite resin is prepared by mixing the raw materials evenly.

[0099] The DSC curve of the composite resin prepared in this embodiment is shown in the figure below. Figure 4 As shown.

[0100] Example 4

[0101] The first aspect of this embodiment provides a halogen-free flame-retardant vinyl ester resin, the raw materials of which, by mass percentage, are 49.91% epoxy resin, 15.68% unsaturated monocarboxylic acid, 0.082% polymerization inhibitor, 0.68% catalyst, 33.11% crosslinking monomer, and 0.538% coupling agent.

[0102] The epoxy resin is a dicyclopentadiene phenol epoxy resin and a halogen-free flame-retardant epoxy resin; the mass ratio of the dicyclopentadiene phenol epoxy resin and the halogen-free flame-retardant epoxy resin is 26:16.96.

[0103] The unsaturated monocarboxylic acid mentioned is methacrylic acid (CAS No.: 79-41-4).

[0104] The polymerization inhibitors are p-hydroxyanisole (CAS No.: 150-76-5), 4-tert-butylcatechol (CAS No.: 98-29-3), and hydroquinone (CAS No.: 123-31-9); the mass ratio of p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone is 3.8:2.7:0.6.

[0105] The catalyst is triphenylphosphine (CAS No.: 603-35-0) and benzyltrimethylammonium chloride (CAS No.: 56-93-9); the mass ratio of triphenylphosphine to benzyltrimethylammonium chloride is 1.5:4.4.

[0106] The crosslinking monomer is styrene (CAS No.: 100-42-5).

[0107] The coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane (CAS No.: 2530-85-0).

[0108] The second aspect of this embodiment provides a method for preparing a halogen-free flame-retardant vinyl ester resin, comprising the following steps:

[0109] Dicyclopentadiene phenol epoxy resin and halogen-free flame-retardant epoxy resin were added to a reactor and heated to 80°C to melt them. Then, p-hydroxyanisole and 4-tert-butylcatechol were added, and the mixture was kept at 80°C and stirred for 10 minutes. Methacrylic acid was added, and after thorough stirring, triphenylphosphine and benzyltrimethylammonium chloride were added. Cooling water was turned on, and the reactor temperature was controlled at a rate of 20°C / h, until the final reactor temperature reached 115°C. Starting at 110°C, the epoxy value and acid value were tested every 0.5 hours. The reaction endpoint was reached when the epoxy value dropped to 0.02 eq / 100g and the acid value dropped to 15 mg KOH / g. The temperature was then lowered to 80°C, and hydroquinone, styrene, and γ-(methacryloyloxy)propyltrimethoxysilane were added. Stirring continued for 1.0 hour to obtain the halogen-free flame-retardant vinyl ester resin.

[0110] The third aspect of this embodiment provides a composite resin, the raw materials for which are prepared by mass percentage as follows: 35.99% halogen-free flame-retardant vinyl ester resin, 47.48% high-temperature resistant vinyl ester resin, 0.03% second polymerization inhibitor, and 16.5% crosslinkable monomer.

[0111] The second polymerization inhibitor is o-methylhydroquinone (CAS No.: 95-71-6).

[0112] The crosslinkable monomers are pentaerythritol triacrylate (CAS No.: 3524-68-3) and trimethylolpropane triacrylate (CAS No.: 15625-89-5), with a mass ratio of pentaerythritol triacrylate to trimethylolpropane triacrylate of 8.0:8.5.

[0113] The preparation method of the high-temperature resistant vinyl ester resin is as follows: 279.7 kg of phenolic epoxy resin SQPN-048 (purchased from Shandong Shengquan New Material Co., Ltd.) and 45.8 kg of multifunctional epoxy resin AG-80 (purchased from Shanghai Huayi Resin Co., Ltd.) are added to a reaction vessel, heated to 80℃ and melted, then 0.22 kg of p-hydroxyanisole (CAS No.: 150-76-5) is added, the temperature is maintained at 80±2℃, and stirred for 0.5 h, then 161.7 kg of methacrylic acid (CAS No.) is added. The reaction mixture consisted of 79-41-4), 1.13 kg of triphenylphosphine (CAS No.: 603-35-0), and 4.14 kg of benzyltrimethylammonium chloride (CAS No.: 56-93-9). Cooling water was turned on, and the heating rate of the reactor was controlled at 20℃ / h. The final reactor temperature reached 115℃. Starting from 110℃, the epoxy value and acid value were tested every 0.5h. The reaction endpoint was reached when the epoxy value dropped to 0.02eq / 100g and the acid value dropped to 14mgKOH / g, yielding a high-temperature resistant vinyl ester resin prepolymer. The mixture was cooled to 80℃, and 0.26 kg of 4-tert-butylcatechol (CAS No.: 98-29-3), 0.045 kg of hydroquinone (CAS No.: 123-31-9), 288.6 kg of styrene (CAS No.: 100-42-5), 150.9 kg of trimethylolpropane triacrylate (CAS No.: 15625-89-5), 47.4 kg of triallyl cyanurate (CAS No.: 101-37-1), and 5.0 kg of γ-(methacryloyloxy)propyltrimethoxysilane KH570 (CAS No.: 2530-85-0) were added. The mixture was stirred for 1.0 h to obtain a high-temperature resistant vinyl ester resin.

[0114] The composite resin is prepared by mixing the raw materials evenly.

[0115] The DSC curve of the composite resin prepared in this embodiment is shown in the figure below. Figure 5 As shown.

[0116] Example 5

[0117] The first aspect of this embodiment provides a halogen-free flame-retardant vinyl ester resin, the raw materials of which, by mass percentage, are 51.91% epoxy resin, 13.66% unsaturated monocarboxylic acid, 0.083% polymerization inhibitor, 0.7% catalyst, 33.11% crosslinking monomer, and 0.537% coupling agent.

[0118] The epoxy resin is a dicyclopentadiene phenol epoxy resin and a halogen-free flame-retardant epoxy resin; the mass ratio of the dicyclopentadiene phenol epoxy resin and the halogen-free flame-retardant epoxy resin is 26:16.96.

[0119] The unsaturated monocarboxylic acid mentioned is acrylic acid (CAS No.: 79-10-7).

[0120] The polymerization inhibitors are p-hydroxyanisole (CAS No.: 150-76-5), 4-tert-butylcatechol (CAS No.: 98-29-3), and hydroquinone (CAS No.: 123-31-9); the mass ratio of p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone is 3.7:2.6:0.6.

[0121] The catalyst is triphenylphosphine (CAS No.: 603-35-0) and benzyltrimethylammonium chloride (CAS No.: 56-93-9); the mass ratio of triphenylphosphine to benzyltrimethylammonium chloride is 1.5:4.3.

[0122] The crosslinking monomer is styrene (CAS No.: 100-42-5).

[0123] The coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane (CAS No.: 2530-85-0).

[0124] The second aspect of this embodiment provides a method for preparing a halogen-free flame-retardant vinyl ester resin, comprising the following steps:

[0125] Dicyclopentadiene phenol epoxy resin and halogen-free flame-retardant epoxy resin were added to a reactor and heated to 80°C to melt them. Then, p-hydroxyanisole and 4-tert-butylcatechol were added, and the mixture was kept at 80°C and stirred for 10 minutes. Acrylic acid was added, and after thorough stirring, triphenylphosphine and benzyltrimethylammonium chloride were added. Cooling water was turned on, and the reactor temperature was controlled at a rate of 20°C / h, until the final reactor temperature reached 115°C. Starting at 110°C, the epoxy value and acid value were tested every 0.5 hours. The reaction endpoint was reached when the epoxy value dropped to 0.02 eq / 100g and the acid value dropped to 15 mg KOH / g. The temperature was then lowered to 80°C, and hydroquinone, styrene, and γ-(methacryloyloxy)propyltrimethoxysilane were added. Stirring continued for 1.0 hour to obtain the halogen-free flame-retardant vinyl ester resin.

[0126] The third aspect of this embodiment provides a composite resin, the raw materials for which are prepared by mass percentage as follows: 35.99% halogen-free flame-retardant vinyl ester resin, 47.48% high-temperature resistant vinyl ester resin, 0.03% second polymerization inhibitor, and 16.5% crosslinkable monomer.

[0127] The second polymerization inhibitor is o-methylhydroquinone (CAS No.: 95-71-6).

[0128] The crosslinkable monomers are pentaerythritol triacrylate (CAS No.: 3524-68-3) and trimethylolpropane triacrylate (CAS No.: 15625-89-5), with a mass ratio of pentaerythritol triacrylate to trimethylolpropane triacrylate of 8.0:8.5.

[0129] The preparation method of the high-temperature resistant vinyl ester resin is as follows: 279.7 kg of phenolic epoxy resin SQPN-048 (purchased from Shandong Shengquan New Material Co., Ltd.) and 45.8 kg of multifunctional epoxy resin AG-80 (purchased from Shanghai Huayi Resin Co., Ltd.) are added to a reaction vessel, heated to 80℃ and melted, then 0.22 kg of p-hydroxyanisole (CAS No.: 150-76-5) is added, the temperature is maintained at 80±2℃, and stirred for 0.5 h, then 161.7 kg of methacrylic acid (CAS No.) is added. The reaction mixture consisted of 79-41-4), 1.13 kg of triphenylphosphine (CAS No.: 603-35-0), and 4.14 kg of benzyltrimethylammonium chloride (CAS No.: 56-93-9). Cooling water was turned on, and the heating rate of the reactor was controlled at 20℃ / h. The final reactor temperature reached 115℃. Starting from 110℃, the epoxy value and acid value were tested every 0.5h. The reaction endpoint was reached when the epoxy value dropped to 0.02eq / 100g and the acid value dropped to 14mgKOH / g, yielding a high-temperature resistant vinyl ester resin prepolymer. The mixture was cooled to 80℃, and 0.26 kg of 4-tert-butylcatechol (CAS No.: 98-29-3), 0.045 kg of hydroquinone (CAS No.: 123-31-9), 288.6 kg of styrene (CAS No.: 100-42-5), 150.9 kg of trimethylolpropane triacrylate (CAS No.: 15625-89-5), 47.4 kg of triallyl cyanurate (CAS No.: 101-37-1), and 5.0 kg of γ-(methacryloyloxy)propyltrimethoxysilane KH570 (CAS No.: 2530-85-0) were added. The mixture was stirred for 1.0 h to obtain a high-temperature resistant vinyl ester resin.

[0130] The composite resin is prepared by mixing the raw materials evenly.

[0131] The DSC curve of the composite resin prepared in this embodiment is shown in the figure below. Figure 6 As shown.

[0132] Example 6

[0133] The first aspect of this embodiment provides a halogen-free flame-retardant vinyl ester resin, the raw materials of which, by mass percentage, are 49.91% epoxy resin, 15.68% unsaturated monocarboxylic acid, 0.082% polymerization inhibitor, 0.68% catalyst, 33.11% crosslinking monomer, and 0.538% coupling agent.

[0134] The epoxy resin is a dicyclopentadiene phenol epoxy resin and a halogen-free flame-retardant epoxy resin; the mass ratio of the dicyclopentadiene phenol epoxy resin and the halogen-free flame-retardant epoxy resin is 26:16.96.

[0135] The unsaturated monocarboxylic acid mentioned is methacrylic acid (CAS No.: 79-41-4).

[0136] The polymerization inhibitors are p-hydroxyanisole (CAS No.: 150-76-5), 4-tert-butylcatechol (CAS No.: 98-29-3), and hydroquinone (CAS No.: 123-31-9); the mass ratio of p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone is 3.8:2.7:0.6.

[0137] The catalyst is triphenylphosphine (CAS No.: 603-35-0) and benzyltrimethylammonium chloride (CAS No.: 56-93-9); the mass ratio of triphenylphosphine to benzyltrimethylammonium chloride is 1.5:4.4.

[0138] The crosslinking monomer is styrene (CAS No.: 100-42-5).

[0139] The coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane (CAS No.: 2530-85-0).

[0140] The second aspect of this embodiment provides a method for preparing a halogen-free flame-retardant vinyl ester resin, comprising the following steps:

[0141] Dicyclopentadiene phenol epoxy resin and halogen-free flame-retardant epoxy resin were added to a reactor and heated to 80°C to melt them. Then, p-hydroxyanisole and 4-tert-butylcatechol were added, and the mixture was kept at 80°C and stirred for 10 minutes. Methacrylic acid was added, and after thorough stirring, triphenylphosphine and benzyltrimethylammonium chloride were added. Cooling water was turned on, and the reactor temperature was controlled at a rate of 20°C / h, until the final reactor temperature reached 115°C. Starting at 110°C, the epoxy value and acid value were tested every 0.5 hours. The reaction endpoint was reached when the epoxy value dropped to 0.021 eq / 100g and the acid value dropped to 14 mg KOH / g. The temperature was then lowered to 80°C, and hydroquinone, styrene, and γ-(methacryloyloxy)propyltrimethoxysilane were added. Stirring continued for 1.0 hour to obtain the halogen-free flame-retardant vinyl ester resin.

[0142] The third aspect of this embodiment provides a composite resin, the raw materials for preparing the composite resin being: 30% halogen-free flame-retardant vinyl ester resin, 44.985% high-temperature resistant vinyl ester resin, 0.015% second polymerization inhibitor, 15% crosslinkable monomer, and 10% additive flame retardant.

[0143] The second polymerization inhibitor is o-methylhydroquinone (CAS No.: 95-71-6).

[0144] The crosslinkable monomers are pentaerythritol triacrylate (CAS No.: 3524-68-3) and trimethylolpropane triacrylate (CAS No.: 15625-89-5), with a mass ratio of pentaerythritol triacrylate to trimethylolpropane triacrylate of 7:8.

[0145] The additive flame retardant is aluminum hydroxide (model: ON-908) (CAS No.: 21645-51-2).

[0146] The preparation method of the high-temperature resistant vinyl ester resin is as follows: 279.7 kg of phenolic epoxy resin SQPN-048 (purchased from Shandong Shengquan New Material Co., Ltd.) and 45.8 kg of multifunctional epoxy resin AG-80 (purchased from Shanghai Huayi Resin Co., Ltd.) are added to a reaction vessel, heated to 80℃ and melted, then 0.22 kg of p-hydroxyanisole (CAS No.: 150-76-5) is added, the temperature is maintained at 80±2℃, and stirred for 0.5 h, then 161.7 kg of methacrylic acid (CAS No.) is added. The reaction mixture consisted of 79-41-4), 1.13 kg of triphenylphosphine (CAS No.: 603-35-0), and 4.14 kg of benzyltrimethylammonium chloride (CAS No.: 56-93-9). Cooling water was turned on, and the heating rate of the reactor was controlled at 20℃ / h. The final reactor temperature reached 115℃. Starting from 110℃, the epoxy value and acid value were tested every 0.5h. The reaction endpoint was reached when the epoxy value dropped to 0.02eq / 100g and the acid value dropped to 14mgKOH / g, yielding a high-temperature resistant vinyl ester resin prepolymer. The mixture was cooled to 80℃, and 0.26 kg of 4-tert-butylcatechol (CAS No.: 98-29-3), 0.045 kg of hydroquinone (CAS No.: 123-31-9), 288.6 kg of styrene (CAS No.: 100-42-5), 150.9 kg of trimethylolpropane triacrylate (CAS No.: 15625-89-5), 47.4 kg of triallyl cyanurate (CAS No.: 101-37-1), and 5.0 kg of γ-(methacryloyloxy)propyltrimethoxysilane KH570 (CAS No.: 2530-85-0) were added. The mixture was stirred for 1.0 h to obtain a high-temperature resistant vinyl ester resin.

[0147] The composite resin is prepared by mixing the raw materials evenly.

[0148] The DSC curve of the composite resin prepared in this embodiment is shown in the figure below. Figure 7 As shown.

[0149] Comparative Example 1

[0150] The first aspect of this comparative example provides a halogen-free flame-retardant vinyl ester resin, the raw materials of which, by mass percentage, are 54.01% epoxy resin, 18.27% unsaturated monocarboxylic acid, 0.09% polymerization inhibitor, 0.75% catalyst, 26.37% crosslinking monomer, and 0.51% coupling agent.

[0151] The epoxy resin mentioned is a phosphorus-containing epoxy resin (DOPO-HQ type modified phenolic epoxy);

[0152] The unsaturated monocarboxylic acid mentioned is methacrylic acid (CAS No.: 79-41-4).

[0153] The polymerization inhibitors are p-hydroxyanisole (CAS No.: 150-76-5), 4-tert-butylcatechol (CAS No.: 98-29-3), and hydroquinone (CAS No.: 123-31-9); the mass ratio of p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone is 4.4:3.6:0.6.

[0154] The catalyst is triphenylphosphine (CAS No.: 603-35-0) and benzyltrimethylammonium chloride (CAS No.: 56-93-9); the mass ratio of triphenylphosphine to benzyltrimethylammonium chloride is 1.9:5.6.

[0155] The crosslinking monomer is styrene (CAS No.: 100-42-5).

[0156] The coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane (CAS No.: 2530-85-0).

[0157] The second aspect of this comparative example provides a method for preparing a halogen-free flame-retardant vinyl ester resin, comprising the following steps:

[0158] Phosphorus-containing epoxy resin was added to a reactor according to the specified ratio. The mixture was heated to 80°C and stirred for a period of time until the temperature stabilized. Then, p-hydroxyanisole and 4-tert-butylcatechol were added, and the mixture was kept at 80°C and stirred for 10 minutes. Methacrylic acid was added, and after stirring evenly, triphenylphosphine and benzyltrimethylammonium chloride were added. Cooling water was turned on, and the heating rate of the reactor was controlled at 20°C / h. The final reactor temperature reached 115°C. Starting from 110°C, the epoxy value and acid value were tested every 0.5 hours. The reaction endpoint was reached when the epoxy value dropped to 0.025 eq / 100g and the acid value dropped to 14 mgKOH / g. Then, the temperature was lowered to 80°C, and hydroquinone, styrene, and γ-(methacryloyloxy)propyltrimethoxysilane were added. Stirring was continued for 1.0 hour to obtain halogen-free flame-retardant vinyl ester resin.

[0159] The third aspect of this comparative example provides a composite resin, the raw materials for which are prepared by mass percentage as follows: 34.99% halogen-free flame-retardant vinyl ester resin, 48.98% high-temperature resistant vinyl ester resin, 0.03% second polymerization inhibitor, and 16% crosslinkable monomer.

[0160] The second polymerization inhibitor is o-methylhydroquinone (CAS No.: 95-71-6).

[0161] The crosslinkable monomers are pentaerythritol triacrylate (CAS No.: 3524-68-3) and trimethylolpropane triacrylate (CAS No.: 15625-89-5), with a mass ratio of pentaerythritol triacrylate to trimethylolpropane triacrylate of 7.5:8.5.

[0162] The preparation method of the high-temperature resistant vinyl ester resin is as follows: 279.7 kg of phenolic epoxy resin SQPN-048 (purchased from Shandong Shengquan New Material Co., Ltd.) and 45.8 kg of multifunctional epoxy resin AG-80 (purchased from Shanghai Huayi Resin Co., Ltd.) are added to a reaction vessel, heated to 80℃ and melted, then 0.22 kg of p-hydroxyanisole (CAS No.: 150-76-5) is added, the temperature is maintained at 80±2℃, and stirred for 0.5 h, then 161.7 kg of methacrylic acid (CAS No.) is added. The reaction mixture consisted of 79-41-4), 1.13 kg of triphenylphosphine (CAS No.: 603-35-0), and 4.14 kg of benzyltrimethylammonium chloride (CAS No.: 56-93-9). Cooling water was turned on, and the heating rate of the reactor was controlled at 20℃ / h. The final reactor temperature reached 115℃. Starting from 110℃, the epoxy value and acid value were tested every 0.5h. The reaction endpoint was reached when the epoxy value dropped to 0.02eq / 100g and the acid value dropped to 14mgKOH / g, yielding a high-temperature resistant vinyl ester resin prepolymer. The mixture was cooled to 80℃, and 0.26 kg of 4-tert-butylcatechol (CAS No.: 98-29-3), 0.045 kg of hydroquinone (CAS No.: 123-31-9), 288.6 kg of styrene (CAS No.: 100-42-5), 150.9 kg of trimethylolpropane triacrylate (CAS No.: 15625-89-5), 47.4 kg of triallyl cyanurate (CAS No.: 101-37-1), and 5.0 kg of γ-(methacryloyloxy)propyltrimethoxysilane KH570 (CAS No.: 2530-85-0) were added. The mixture was stirred for 1.0 h to obtain a high-temperature resistant vinyl ester resin.

[0163] The composite resin is prepared by mixing the raw materials evenly.

[0164] The DSC curve of the composite resin prepared in this comparative example is shown in the figure below. Figure 8 As shown.

[0165] Comparative Example 2

[0166] The first aspect of this comparative example provides a halogen-free flame-retardant vinyl ester resin, the raw materials of which, by mass percentage, are 54.01% epoxy resin, 18.27% unsaturated monocarboxylic acid, 0.09% polymerization inhibitor, 0.75% catalyst, 26.37% crosslinking monomer, and 0.51% coupling agent.

[0167] The epoxy resin mentioned is a phosphorus-containing epoxy resin (DOPO-HQ type modified phenolic epoxy);

[0168] The unsaturated monocarboxylic acid mentioned is methacrylic acid (CAS No.: 79-41-4).

[0169] The polymerization inhibitors are p-hydroxyanisole (CAS No.: 150-76-5), 4-tert-butylcatechol (CAS No.: 98-29-3), and hydroquinone (CAS No.: 123-31-9); the mass ratio of p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone is 4.4:3.6:0.6.

[0170] The catalyst is triphenylphosphine (CAS No.: 603-35-0) and benzyltrimethylammonium chloride (CAS No.: 56-93-9); the mass ratio of triphenylphosphine to benzyltrimethylammonium chloride is 1.9:5.6.

[0171] The crosslinking monomer is styrene (CAS No.: 100-42-5).

[0172] The coupling agent is γ-(methacryloyloxy)propyltrimethoxysilane (CAS No.: 2530-85-0).

[0173] The second aspect of this comparative example provides a method for preparing a halogen-free flame-retardant vinyl ester resin, comprising the following steps:

[0174] Phosphorus-containing epoxy resin was added to a reactor according to the specified ratio. The mixture was heated to 80°C and stirred for a period of time until the temperature stabilized. Then, p-hydroxyanisole and 4-tert-butylcatechol were added, and the mixture was kept at 80°C and stirred for 10 minutes. Methacrylic acid was added, and after stirring evenly, triphenylphosphine and benzyltrimethylammonium chloride were added. Cooling water was turned on, and the heating rate of the reactor was controlled at 20°C / h. The final reactor temperature reached 115°C. Starting from 110°C, the epoxy value and acid value were tested every 0.5 hours. The reaction endpoint was reached when the epoxy value dropped to 0.025 eq / 100g and the acid value dropped to 14 mgKOH / g. Then, the temperature was lowered to 80°C, and hydroquinone, styrene, and γ-(methacryloyloxy)propyltrimethoxysilane were added. Stirring was continued for 1.0 hour to obtain halogen-free flame-retardant vinyl ester resin.

[0175] The third aspect of this comparative example provides a composite resin, the raw materials for which are prepared by mass percentage as follows: 30% halogen-free flame-retardant vinyl ester resin, 44.985% high-temperature resistant vinyl ester resin, 0.015% second polymerization inhibitor, 15% crosslinkable monomer, and 10% additive flame retardant.

[0176] The second polymerization inhibitor is o-methylhydroquinone (CAS No.: 95-71-6).

[0177] The additive flame retardant is aluminum hydroxide (ON-908) (CAS No.: 21645-51-2).

[0178] The crosslinkable monomers are pentaerythritol triacrylate (CAS No.: 3524-68-3) and trimethylolpropane triacrylate (CAS No.: 15625-89-5), with a mass ratio of pentaerythritol triacrylate to trimethylolpropane triacrylate of 7:8.

[0179] The preparation method of the high-temperature resistant vinyl ester resin is as follows: 279.7 kg of phenolic epoxy resin SQPN-048 (purchased from Shandong Shengquan New Material Co., Ltd.) and 45.8 kg of multifunctional epoxy resin AG-80 (purchased from Shanghai Huayi Resin Co., Ltd.) are added to a reaction vessel, heated to 80℃ and melted, then 0.22 kg of p-hydroxyanisole (CAS No.: 150-76-5) is added, the temperature is maintained at 80±2℃, and stirred for 0.5 h, then 161.7 kg of methacrylic acid (CAS No.: 150-76-5) is added. 1.13 kg of triphenylphosphine (CAS No.: 603-35-0) and 4.14 kg of benzyltrimethylammonium chloride (CAS No.: 56-93-9) were added. The cooling water was turned on, and the heating rate of the reactor was controlled at 20℃ / h. The final reactor temperature reached 115℃. When the temperature reached 110℃, the epoxy value and acid value were tested every 0.5h. The reaction ended when the epoxy value dropped to 0.02eq / 100g and the acid value dropped to 14mgKOH / g, and the high-temperature resistant vinyl ester resin prepolymer was obtained. The mixture was cooled to 80℃, and 0.26 kg of 4-tert-butylcatechol (CAS No.: 98-29-3), 0.045 kg of hydroquinone (CAS No.: 123-31-9), 288.6 kg of styrene (CAS No.: 100-42-5), 150.9 kg of trimethylolpropane triacrylate (CAS No.: 15625-89-5), 47.4 kg of triallyl cyanurate (CAS No.: 101-37-1), and 5.0 kg of γ-(methacryloyloxy)propyltrimethoxysilane KH570 (CAS No.: 2530-85-0) were added. The mixture was stirred for 1.0 h to obtain a high-temperature resistant vinyl ester resin.

[0180] The composite resin is prepared by mixing the raw materials evenly.

[0181] The DSC curve of the composite resin prepared in this comparative example is shown in the figure below. Figure 9 As shown.

[0182] Performance testing

[0183] 1. Glass transition temperature (Tg) test

[0184] Test subjects: Composite resins prepared in Examples 1-6 and Comparative Examples 1-2

[0185] Test standard: GB / T 19466.2-2004; performed according to Plastics—Differential Scanning Calorimetry (DSC) Part 2—Determination of Glass Transition Temperature, and the results are recorded in Table 1.

[0186] 2. Limiting Oxygen Index Test

[0187] Test subjects: Composite resins prepared in Examples 1-6 and Comparative Examples 1-2

[0188] Test standard: GB / T2406.2-2009; The test shall be performed according to the procedure for determining the flammability of plastics by oxygen index method – Part 2 – Room temperature test, and the results shall be recorded in Table 1.

[0189] Table 1

[0190]

[0191] 3. Mechanical property testing

[0192] Test subjects: Composite resins prepared in Examples 1-6 and Comparative Examples 1-2

[0193] The test methods and test results are shown in Table 2. Six parallel samples of the heat-resistant vinyl ester resin for each example and comparative example were prepared, and the average value was taken.

[0194] Table 2

[0195]

[0196] The data above shows that the high-temperature resistant, halogen-free flame-retardant vinyl ester resin has good flame-retardant properties, meeting the requirements for flame retardancy, while having almost no impact on the mechanical properties of the product. It can be used normally in flame-retardant vinyl ester resin fiberglass products.

Claims

1. A composite resin, characterized by, The raw materials for preparing the composite resin include, by mass percentage, at least: 30-45% halogen-free flame-retardant vinyl ester resin, 40-50% high-temperature resistant vinyl ester resin, 0.02-0.05% secondary polymerization inhibitor, 10-20% crosslinkable monomer, and 0-20% additive flame retardant. The crosslinkable monomers include at least one or more of styrene, trimethylolpropane triacrylate, tri(methacrylate)trimethylolpropane, pentaerythritol triacrylate, and dipentaerythritol hexaacrylate; The raw materials for preparing the halogen-free flame-retardant vinyl ester resin include, by mass percentage, at least: 40-60% epoxy resin, 13-18% unsaturated monocarboxylic acid, 0.05-0.1% polymerization inhibitor, 0.5-0.7% catalyst, 24-35% crosslinking monomer, and 0.3-0.7% coupling agent; The epoxy resin mentioned above includes at least one or more of the following: halogen-free flame-retardant epoxy resin, phenol-biphenyl epoxy resin, phenol-aromatic epoxy resin, and dicyclopentadiene-phenol epoxy resin. The polymerization inhibitors include p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone; the mass ratio of p-hydroxyanisole, 4-tert-butylcatechol, and hydroquinone is (3-6):(0.1-3):(0.5-4). The crosslinking monomers include at least one or more of divinylbenzene, diallyl phthalate, TAIC, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and neopentyl glycol dimethacrylate; The preparation method of the halogen-free flame-retardant vinyl ester resin includes the following steps: epoxy resin is added to a reaction vessel, kept at 80±2℃ and stirred until melted, then unsaturated monocarboxylic acid and polymerization inhibitors p-hydroxyanisole and 4-tert-butylcatechol are added, kept at 80±2℃ and stirred for 0.3-0.8h, then a catalyst is added, cooling water is turned on, and the heating rate of the reaction vessel is controlled at 18-22℃ / h. The final temperature of the reaction vessel reaches 115±2℃. When the temperature reaches 105-110℃, the epoxy value and acid value are tested every 0.3-0.8h. The reaction endpoint is when the epoxy value is less than 0.02mol / 100g and the acid value is less than 14mgKOH / g. Then the temperature is lowered to 75-85℃, and polymerization inhibitors hydroquinone, crosslinking monomers, and coupling agents are added. Stirring is continued for 0.5-1.0h to obtain the halogen-free flame-retardant vinyl ester resin. The preparation method of the high-temperature resistant vinyl ester resin is as follows: 279.7 kg of phenolic epoxy resin SQPN-048 and 45.8 kg of multifunctional epoxy resin AG-80 are added to a reactor and heated to 80°C to melt them. Then, 0.22 kg of p-hydroxyanisole is added, and the mixture is kept at 80±2°C and stirred for 0.5 h. 161.7 kg of methacrylic acid, 1.13 kg of triphenylphosphine, and 4.14 kg of benzyltrimethylammonium chloride are added. The cooling water is turned on, and the heating rate of the reactor is controlled at 20°C / h. The final reactor temperature reaches 115°C, and the temperature reaches 110°C. Initially, the epoxy value and acid value were tested every 0.5 hours. The reaction endpoint was reached when the epoxy value dropped to 0.02 eq / 100g and the acid value dropped to 14 mg KOH / g, yielding a high-temperature resistant vinyl ester resin prepolymer. The temperature was then lowered to 80℃, and 0.26 kg of 4-tert-butylcatechol, 0.045 kg of hydroquinone, 288.6 kg of styrene, 150.9 kg of trimethylolpropane triacrylate, 47.4 kg of triallyl cyanurate, and 5.0 kg of γ-(methacryloyloxy)propyltrimethoxysilane were added. The mixture was stirred for another 1.0 h to obtain the high-temperature resistant vinyl ester resin.

2. The composite resin according to claim 1, characterized by The catalyst comprises at least one or more of the following: trimethylamine, methyl sulfide, diethylene glycol dimethyl ether, triphenylphosphine, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyldimethylamine, imidazole, 1-methylimidazolium, 2-ethyl-4-methylimidazolium, and 2-heptadecylimidazolium.

3. The composite resin according to claim 1, characterized by The second polymerization inhibitor comprises at least one of hydroquinone, 4-tert-butylcatechol, 4-hydroxy-2,2,6,6-tetramethylpiperidine oxide, p-benzoquinone, p-hydroxyanisole, and o-methylhydroquinone.

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