A kind of preparation method of modified vinyl ester resin

Abstract

The present invention discloses a method for preparing a modified vinyl ester resin. The method comprises the following steps: (1) reacting an epoxy-terminated silicone oil with an organic carboxylic acid, and then reacting with a diisocyanate to obtain a modified silicone oil with an isocyanate terminal group; (2) reacting an epoxy resin with an unsaturated monobasic acid, and then adding a crosslinking agent; (3) reacting the product obtained in step (2) with the modified silicone oil in step (1) to obtain a modified vinyl ester resin. The present invention adopts a linear polydimethylsiloxane with an epoxy functional group as a toughening agent, which can be used as a modified reactive site, has good molecular chain flexibility, and has a good toughening effect. By synthesizing a modified silicone oil with an isocyanate terminal group and reacting it with a vinyl ester resin, the product quality is stable, the modified resin has good compatibility with the base resin, and the toughening modification effect is better.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a method for synthesizing a modified vinyl ester resin. Background Art

[0002] Vinyl ester resin is prepared by the ring-opening addition reaction of epoxy resin and monounsaturated carboxylic acid, and the product is dissolved in unsaturated polymerizable monomer. Under the initiation of organic peroxide, it can be cross-linked and cured. The cured product has high mechanical strength, excellent chemical resistance and hydrolysis stability, and is widely used in chemical industry, metallurgy, papermaking, aerospace and other fields. However, vinyl ester resin is a free radical cured thermosetting resin with a high cross-linking density, which leads to high brittleness of the resin and makes it difficult to meet the toughness requirements of the matrix resin for certain special products. Therefore, improving the brittleness of vinyl ester resin is of great significance for improving the performance of existing products and broadening the application field.

[0003] Patent CN103304749A discloses a method for modifying vinyl ester resin, using a long-chain saturated dibasic acid to partially replace an unsaturated monobasic acid to react with an epoxy resin, introducing a flexible dibasic acid molecule long chain into the molecular main chain, and improving the flexibility of the molecular chain. Patent CN1793196A discloses a method for modifying vinyl ester resin, using a carboxyl-terminated liquid nitrile rubber, reacting with an unsaturated monocarboxylic acid, a saturated dibasic fatty acid and an epoxy resin in the presence of a catalyst, and obtaining a vinyl ester resin modified with nitrile rubber. However, the unreacted nitrile rubber has poor miscibility with styrene solvents, which easily leads to stratification and affects the stability of the final product. Zhou Runpei (GRP / Composite Materials, 2000 (2): 21-22) et al. introduced a flexible isocyanate group into the molecular structure of the vinyl ester resin, so that the synthesized resin molecular chain contains a polyurethane group, but due to the use of isocyanate monomer modification, the improvement of the resin toughness is limited. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a modified vinyl ester resin to improve the toughness of the resin. The method has the advantages of simple operation, few side reactions, no by-product generation, high toughness and stable quality. The obtained product can meet the requirements of fan blades, sports equipment, petrochemical equipment and the like for the toughness of the base resin.

[0005] The present invention provides a method for preparing a modified vinyl ester resin, comprising the following steps:

[0006] (1) Adding catalyst A to epoxy-terminated silicone oil and organic carboxylic acid, reacting at 90-130°C, stopping the reaction when the acid value drops below 12 mgKOH / g, cooling to room temperature, adding diisocyanate and catalyst B, reacting at 70-90°C, and when the isocyanate content remains unchanged, the reaction is terminated to obtain a modified silicone oil with an isocyanate terminal group;

[0007] (2) reacting the epoxy resin and the unsaturated monobasic acid in the presence of catalyst A and a polymerization inhibitor at 90-130° C. until the acid value is reduced to below 12 mgKOH / g, which is the reaction end point, adding a crosslinking agent, and stirring and mixing uniformly;

[0008] (3) The product obtained in step (2) and the modified silicone oil in step (1) are reacted at 70-90° C. in the presence of catalyst B, and the isocyanate content is measured until it is 0 to obtain a modified vinyl ester resin.

[0009] The molecular weight of the epoxy-terminated silicone oil in step (1) of the present invention is 500-6000, for example, JF-852 series epoxy-terminated silicone oil-1000, epoxy-terminated silicone oil-2000, and epoxy-terminated silicone oil-3000 from Wuhan Huaxiang Kejie Biotechnology Co., Ltd.

[0010] The organic carboxylic acid described in the present invention is one or more of acetic acid, propionic acid or butyric acid.

[0011] The molar ratio of the epoxy-terminated silicone oil to the organic carboxylic acid is 1:2.

[0012] The catalyst A described in the present invention refers to an amine organic base catalyst such as tributylamine, triethanolamine, triethylamine, etc. or a reduced salt catalyst such as a quaternary ammonium salt, such as one or more of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, dodecyltrimethylammonium chloride, tetrabutylammonium bromide, benzyltriethylammonium bromide, etc.

[0013] In step (1) of the present invention, the amount of catalyst A used is 0.1-2 wt %, based on the sum of the weights of the epoxy-terminated silicone oil and the organic carboxylic acid.

[0014] The diisocyanate described in the present invention is one or more of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate.

[0015] The catalyst B described in the present invention is dibutyltin dilaurate and / or stannous octoate.

[0016] In step (1) of the present invention, the amount of catalyst B used is 0.01-0.5 wt %, based on the sum of the weights of the epoxy-terminated silicone oil and the organic carboxylic acid.

[0017] In step (1) of the present invention, the molar ratio of the amount of diisocyanate to the amount of terminal epoxy silicone oil is 2:1.

[0018] The epoxy resin in step (2) of the present invention is one of bisphenol A epoxy resin E-44, E-51 or E-54.

[0019] The unsaturated monocarboxylic acid described in the present invention is one or more of acrylic acid, methacrylic acid or trans-2-butenoic acid.

[0020] The polymerization inhibitor of the present invention is one or more of hydroquinone, p-tert-butylcatechol, p-benzoquinone, alkyl p-benzoquinone, catechol, tetrachlorobenzoquinone and the like.

[0021] In step (2) of the present invention, based on the sum of the weights of the epoxy resin, the unsaturated monoacid and the crosslinking agent, the amount of the epoxy resin is 35-48%, the amount of the unsaturated monoacid is 10-28%, and the amount of the crosslinking agent is 35-45%.

[0022] In step (2) of the present invention, the amount of catalyst A is 0.1-2%, and the amount of inhibitor is 0.01-0.3%, based on the total weight of epoxy resin, unsaturated monobasic acid and crosslinking agent.

[0023] The crosslinking agent of the present invention is one or more of styrene, p-methylstyrene, α-methylstyrene, methyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, diallyl isophthalate and diallyl terephthalate.

[0024] In step (3) of the present invention, based on the weight of the epoxy resin, the unsaturated monobasic acid, the crosslinking agent and the modified silicone oil, the amount of the modified silicone oil in step (1) is 5-20%.

[0025] In step (3) of the present invention, based on the weight of the epoxy resin, the unsaturated monobasic acid, the crosslinking agent and the modified silicone oil, the amount of catalyst B used is 0.01-0.5%.

[0026] The method of the present invention is simple to operate, has no by-products, meets the requirements of certain materials for the toughness of the matrix resin, and has the following advantages:

[0027] ①Use linear polydimethylsiloxane with epoxy functional group as toughening agent. Since the end group is active epoxy group, it can be used as the reactive site of modification. Since the bond angle of Si-O-Si is larger than CC bond and the bond length is larger, the internal rotation steric hindrance is smaller, the molecular chain has good flexibility and toughening effect.

[0028] ② By synthesizing modified silicone oil with isocyanate terminal groups and reacting with vinyl ester resin, the product quality is stable, the modified resin has good compatibility with the base resin, and the toughening modification effect is better. DETAILED DESCRIPTION

[0029] The invention is described in detail below in conjunction with specific implementation examples. In the specific implementation examples, all components are measured in mass percentage unless otherwise specified.

[0030] Embodiment 1:

[0031] (1) Add 500 g of epoxy-terminated silicone oil with a molecular weight of 1000, 60 g of acetic acid, and 3.36 g of benzyltriethylammonium chloride into a three-necked flask, start stirring, heat to 100°C, keep warm for reaction, measure the acid value every 1 hour, and when the acid value drops to 12 mgKOH / g, the reaction ends. Cool the reaction product to room temperature, add 174.2 g of toluene diisocyanate and 0.17 g of dibutyltin dilaurate, heat to 75°C, keep warm for reaction, measure the isocyanate content every 30 minutes, and when the isocyanate content remains unchanged, the reaction ends, and a modified silicone oil with an isocyanate terminal group is obtained.

[0032] (2) In another three-necked flask, add 460 g of epoxy resin E-44, 182.98 g of methacrylic acid, 5.36 g of tetraethylammonium chloride, and 0.43 g of p-benzoquinone. Start stirring, raise the temperature to 110° C., and keep the temperature to react. Measure the acid value every hour. When the acid value is lower than 12 mgKOH / g, the reaction ends. Add 428.7 g of styrene and stir to mix evenly.

[0033] (3) The reaction product was cooled to room temperature, 56.4 g of the product of step (1) was added, 1.13 g of dibutyltin dilaurate was added, the temperature was raised to about 70° C., and the isocyanate content was measured every 30 minutes. When the isocyanate content was zero, the reaction endpoint was reached to obtain a modified vinyl ester resin.

[0034] Embodiment 2:

[0035] (1) Add 600 g of epoxy-terminated silicone oil with a molecular weight of 2000, 44.5 g of propionic acid, and 3.87 g of tetrabutylammonium bromide into a three-necked flask, start stirring, heat to about 105°C, keep warm for reaction, measure the acid value every hour, stop the reaction when the acid value drops to 12 mgKOH / g, cool the reaction product to room temperature, add 150.2 g of diphenylmethane diisocyanate and 0.32 g of stannous octoate, heat to about 70°C, measure the isocyanate content every 30 minutes, and reach the end point of the reaction when the isocyanate content remains unchanged to obtain a modified silicone oil with an isocyanate terminal group.

[0036] (2) In another three-necked flask, add 400 g of epoxy resin E-51, 154.3 g of acrylic acid, 4.62 g of benzyltriethylammonium bromide, and 0.46 g of catechol. Start stirring and raise the temperature to about 115° C. to keep the temperature for reaction. Measure the acid value every hour. When the acid value is lower than 12 mgKOH / g, the reaction ends. Add 300 g of methyl styrene and 69.5 g of methyl acrylate and stir to mix well.

[0037] (3) Cooling the reaction product to room temperature, adding 102.65 g of the product of step (1), adding 2.05 g of stannous octoate, raising the temperature to about 75° C., measuring the isocyanate content every 30 minutes, and reaching the reaction endpoint when the isocyanate content is zero to obtain a modified vinyl ester resin.

[0038] Embodiment 3:

[0039] (1) Add 1000 g of epoxy-terminated silicone oil with a molecular weight of 3000, 58.7 g of butyric acid, and 5.29 g of triethanolamine into a three-necked flask, start stirring, heat to about 110° C., keep warm for reaction, measure the acid value every hour, stop the reaction when the acid value drops to 12 mgKOH / g, cool the reaction product to room temperature, add 116.1 g of toluene diisocyanate and 0.21 g of dibutyltin dilaurate, heat to 75° C., measure the isocyanate content every 30 minutes, and reach the end point of the reaction when the isocyanate content remains unchanged to obtain a modified silicone oil with an isocyanate terminal group.

[0040] (2) In another three-necked flask, add 700 g of epoxy resin E-54, 361.2 g of methacrylic acid, 8.84 g of triethanolamine, and 1.06 g of tetrachlorobenzoquinone, start stirring, raise the temperature to 115° C., and keep the temperature for reaction. Measure the acid value every hour. When the acid value is lower than 12 mgKOH / g, the reaction ends and the reaction is stopped. Add 400 g of p-methylstyrene and 307.5 g of methyl methacrylate, and stir to mix well.

[0041] (3) Cooling the reaction product to room temperature, adding 312.12 g of the product of step (1), adding 4.16 g of dibutyltin dilaurate, starting stirring, raising the temperature to about 70° C., measuring the isocyanate content every 30 minutes, and reaching the reaction endpoint when the isocyanate content is zero to obtain a modified vinyl ester resin.

[0042] Embodiment 4:

[0043] (1) Add 700 g of epoxy-terminated silicone oil with a molecular weight of 1000, 103.7 g of propionic acid, and 5.63 g of benzyltriethylammonium chloride into a three-necked flask, start stirring, raise the temperature to about 115° C., keep the temperature for reaction, measure the acid value every hour, stop the reaction when the acid value drops to 12 mgKOH / g, cool the reaction product to room temperature, add 243.8 g of toluene diisocyanate, add 0.56 g of dibutyltin dilaurate, start stirring, raise the temperature to 75° C., measure the isocyanate content every 30 minutes, and reach the end point of the reaction when the isocyanate content remains unchanged to obtain a modified silicone oil with an isocyanate terminal group.

[0044] (2) In another three-necked flask, add 800 g of epoxy resin E-51, 308.57 g of acrylic acid, 11.09 g of benzyltriethylammonium chloride, and 1.48 g of hydroquinone, start stirring, and raise the temperature to 115° C. Keep the temperature for reaction, and measure the acid value every hour. When the acid value drops to 12 mgKOH / g, the reaction reaches the end point, and add 500 g of p-methylstyrene and 239 g of methyl acrylate, and stir evenly.

[0045] (3) The reaction product was cooled to room temperature, 461.9 g of the product of step (1) and 6.93 g of dibutyltin dilaurate were added, the temperature was raised to 70° C., and the isocyanate content was measured every 30 minutes. When the isocyanate content was zero, the reaction endpoint was reached to obtain a modified resin.

[0046] Comparative Example 5:

[0047] Add 460g bisphenol A epoxy resin, 182.98g methacrylic acid, 56.4g sebacic acid, 5.36g tetraethylammonium chloride, and 0.43g p-benzoquinone into a three-necked flask, start stirring, gradually increase the temperature, control the reaction temperature to react at 110°C, measure the acid value every hour until the acid value drops below 12mgKOH / g. Cool the reaction product to about 100 degrees Celsius, add 428.7g styrene, and stir evenly to obtain a modified resin.

[0048] Comparative Example 6:

[0049] Add 460g of epoxy resin E-44, 182.98g of methacrylic acid, 5.36g of tetraethylammonium chloride, and 0.43g of p-benzoquinone into a three-necked flask, start stirring, heat to 110°C, keep warm for reaction, measure the acid value every hour, and the reaction end point is when the acid value is lower than 12mgKOH / g. Add 56.4g of terminal epoxy silicone oil with a molecular weight of 1000, add 428.7g of styrene, stir and mix evenly to obtain a modified resin.

[0050] The performance of the products of the embodiments and comparative examples are shown in Table 1.

[0051] Table 1 Performance of Examples and Comparative Examples

[0052]

[0053] The modified resin has a tensile strength of 65-75MPa, a tensile modulus of 2500-3500MPa, a flexural strength of 100-120MPa, an elongation at break of 15-25%, and an impact strength of 30-45kJ / m 2 Compared with the unmodified resin, the toughness of the resin is significantly improved, meeting the requirements of wind power equipment, sports equipment, petrochemical equipment and other materials for the toughness of the matrix resin.

Claims

1. A method for preparing a modified vinyl ester resin, comprising the following steps: (1) Adding catalyst A to epoxy-terminated silicone oil and organic carboxylic acid, reacting at 90-130°C, stopping the reaction when the acid value drops below 12 mgKOH / g, cooling to room temperature, adding diisocyanate and catalyst B, reacting at 70-90°C, and when the isocyanate content remains unchanged, the reaction is terminated to obtain a modified silicone oil with an isocyanate terminal group; (2) reacting the epoxy resin and the unsaturated monobasic acid in the presence of catalyst A and a polymerization inhibitor at 90-130° C. until the acid value is reduced to below 12 mgKOH / g, which is the reaction end point, adding a crosslinking agent, and stirring and mixing uniformly; (3) The product obtained in step (2) and the modified silicone oil in step (1) are reacted at 70-90° C. in the presence of catalyst B, and the isocyanate content is measured until it is 0 to obtain a modified vinyl ester resin.

2. The method according to claim 1, characterized in that The molecular weight of the epoxy-terminated silicone oil in step (1) is 500-6000.

3. The method according to claim 1, characterized in that The organic carboxylic acid is one or more of acetic acid, propionic acid and butyric acid.

4. The method according to claim 1, characterized in that: The molar ratio of the epoxy-terminated silicone oil to the organic carboxylic acid is 1:

2.

5. The method according to claim 1, characterized in that The diisocyanate is one or more of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate.

6. The method according to claim 1, characterized in that The epoxy resin in step (2) is one of bisphenol A epoxy resin E-44, E-51 or E-54.

7. The method according to claim 1, characterized in that The unsaturated monocarboxylic acid is one or more of acrylic acid, methacrylic acid or trans-2-butenoic acid.

8. The method according to claim 1, characterized in that In the step (2), based on the sum of the weights of the epoxy resin, the unsaturated monoacid and the crosslinking agent, the amount of the epoxy resin is 35-48%, the amount of the unsaturated monoacid is 10-28%, and the amount of the crosslinking agent is 35-45%.

9. The method according to claim 1, characterized in that: In the step (3), based on the weight of the epoxy resin, the unsaturated monobasic acid, the crosslinking agent and the modified silicone oil, the amount of the modified silicone oil in the step (1) is 5-20%.

10. The method according to claim 1, characterized in that The crosslinking agent is one or more of styrene, p-methylstyrene, α-methylstyrene, methyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, diallyl isophthalate, and diallyl terephthalate.

Images