Modified epoxidized soybean oil, epoxy resin adhesive and preparation method thereof

Abstract

The invention discloses modified epoxidized soybean oil, epoxy resin glue and a preparation method thereof. The modified epoxidized soybean oil is obtained through a reaction of a cyclodextrin-epoxidized soybean oil inclusion compound and citric acid, and the cyclodextrin-epoxidized soybean oil inclusion compound is obtained through a reaction of cyclodextrin and epoxidized soybean oil. The epoxy resin adhesive is prepared from bisphenol A epoxy resin, modified epoxidized soybean oil, an anhydride curing agent and a curing accelerator. The modified epoxidized soybean oil is added into the epoxy resin adhesive, so that the epoxy resin adhesive has better tensile strength, elongation at break, impact strength and low-temperature impact strength, and the toughening effect is remarkable.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and more specifically, relates to modified epoxy soybean oil, epoxy resin glue and a preparation method thereof. Background Art

[0002] Epoxy resin adhesive is widely used in electronic device sealing, structural parts bonding, coatings, composite materials and other fields due to its excellent mechanical properties, electrical insulation, adhesion and chemical stability. However, after curing, epoxy resin adhesive has high cohesive strength and strong rigidity, but its body is hard and brittle, and its aging resistance, impact resistance, high and low temperature resistance and other properties are poor, which seriously affects its use environment and service life.

[0003] In order to solve the above problems of epoxy resin glue, it is often necessary to introduce toughening agents. In recent years, biomass raw materials represented by epoxidized soybean oil have attracted the attention of academia and industry. They have the characteristics of low cost, wide source, simple processing, environmental protection and pollution-free, high transparency, good chemical stability and thermal stability. At present, they have become important thermosetting resin toughening modifiers. When epoxidized soybean oil is introduced into epoxy resin, its flexible long side chains are grafted to epoxy resin glue through epoxy groups, which can improve the fracture toughness of rigid resin glue to a certain extent, but its toughening effect on epoxy resin glue is still not ideal. Summary of the invention

[0004] Based on this, the purpose of the present invention is to improve the toughness of epoxy resin glue and improve its impact resistance.

[0005] The specific technical solutions for achieving the above-mentioned invention objectives include the following.

[0006] In a first aspect, the present invention provides a modified epoxidized soybean oil, which is obtained by reacting a cyclodextrin-epoxidized soybean oil inclusion compound with citric acid, wherein the cyclodextrin-epoxidized soybean oil inclusion compound is obtained by reacting cyclodextrin with epoxidized soybean oil.

[0007] The second aspect of the present invention provides a method for preparing the modified epoxidized soybean oil, comprising the following steps:

[0008] (1) stirring cyclodextrin and epoxidized soybean oil at 65° C. to 75° C. for 0.5 h to 1.5 h to obtain a cyclodextrin-epoxidized soybean oil inclusion complex;

[0009] (2) reacting the cyclodextrin-epoxidized soybean oil inclusion complex and citric acid at 65° C. to 75° C. for 2 h to 4 h;

[0010] (3) Add N,N-dimethylbenzylamine (BDMA) and react at 75°C to 85°C for 0.5h to 1.5h under vacuum to obtain the product.

[0011] The third aspect of the present invention provides an epoxy resin adhesive, which is prepared from the following raw materials in parts by weight:

[0012]

[0013] The fourth aspect of the present invention provides a method for preparing the above-mentioned epoxy resin glue, comprising the following steps: mixing bisphenol A epoxy resin, modified epoxy soybean oil, anhydride curing agent, and curing accelerator, stirring at a dispersion rate of 200rpm to 300rpm at 25°C to 35°C for 5min to 20min under vacuum conditions, and curing at 95°C to 105°C for 2.5h to 3.5h.

[0014] The present invention firstly prepares a modified epoxy soybean oil by using cyclodextrin, citric acid and epoxy soybean oil as reaction raw materials in a certain molar ratio, and then prepares a high-toughness epoxy resin glue by adding the modified epoxy soybean oil into the epoxy resin system. On the one hand, the hydrophilicity of the outer end of cyclodextrin and the hydrophobicity of the inner part and the carboxyl group introduced by citric acid can significantly improve the compatibility of the epoxy soybean oil in the epoxy resin system, so that the flexible long branched chain in the modified epoxy soybean oil can effectively reduce the brittleness of the epoxy resin, enhance the fracture toughness of the epoxy resin, and make it have higher mechanical properties and ductility; on the other hand, cyclodextrin forms a polyrotaxane in the modified epoxy soybean oil, and the hydroxyl groups on the cyclodextrin can be grafted into the epoxy resin cross-linking network to form a sliding ring cross-linking network structure during the curing process, which can make the cyclodextrin molecules slide and rotate on the chain segments, and can drive the activity of the sliding ring polymer network through the sliding and rotating of the sliding ring when subjected to external stress, thereby achieving the effect of energy dissipation and further toughening the epoxy resin glue. Therefore, the modified epoxidized soybean oil obtained by the synergistic modification of epoxidized soybean oil with cyclodextrin and citric acid can significantly improve the toughness of epoxy resin glue. Compared with the epoxy resin glue prepared using unmodified epoxidized soybean oil, the elongation at break, impact strength and impact strength of the epoxy resin glue prepared using the modified epoxidized soybean oil of the present invention are significantly improved.

[0015] In the modified epoxidized soybean oil formula involved in the technical solution of the present invention, cyclodextrin is added, which has the function of increasing the solubility of epoxidized soybean oil in high polarity systems by utilizing the hydrophilicity of the outer end and the hydrophobicity of the inner end of cyclodextrin, and on the other hand, in the cross-linking and curing process, the hydroxyl groups on the cyclodextrin can be grafted into the epoxy resin cross-linking network to form a sliding ring cross-linking network, thereby increasing the cross-linking degree and giving the cross-linking network a higher fracture toughness. Organic acids cross-link with epoxidized soybean oil, which can not only introduce carboxyl groups to increase the polarity of epoxidized soybean oil, but also thicken, further improving the compatibility of epoxidized soybean oil with epoxy resin. The high-toughness epoxy resin glue prepared by adding modified epoxidized soybean oil, the free carboxyl groups and hydroxyl groups in the modified epoxidized soybean oil promote the curing of epoxy resin, and cyclodextrin forms mechanical interlocking structures such as rotaxanes and catenanes inside the polymer network, thereby enhancing the gelation and mechanical strength of the body; in addition, the sliding and rotation of cyclodextrin molecules on the chain segments drive the activity of the sliding ring polymer network, giving it a unique stress absorption and release mechanism, thereby achieving the purpose of toughening.

[0016] In addition, the sliding ring cross-linking network formed by grafting the hydroxyl groups on cyclodextrin to the epoxy resin cross-linking network during the cross-linking and curing process can increase the cross-linking density of the epoxy resin, and the mechanical interlocking structures such as rotaxanes and catenanes formed by cyclodextrin inside the polymer network can also enhance the gelation of the epoxy resin glue body; the free carboxyl groups and hydroxyl groups introduced into the modified epoxidized soybean oil promote the curing of the epoxy resin. Under the synergistic cooperation of the above-mentioned various factors, the modified epoxidized soybean oil of the present invention can significantly improve the mechanical strength of the obtained epoxy resin glue, and compared with the epoxy resin glue prepared using the unmodified epoxidized soybean oil, the bulk tensile strength of the epoxy resin glue prepared using the modified epoxidized soybean oil of the present invention is also significantly improved.

[0017] The raw materials for preparing the modified epoxidized soybean oil of the present invention are all biomass materials, with low raw material cost, large yield, green and environmental protection, and simple operation, no pollution and high yield in the preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 These are the infrared absorption spectra (FTIR) graphs of epoxidized soybean oil, CD1-ESO10-CA30 prepared in Example 1, CD2-ESO10-CA30 prepared in Example 2, CD5-ESO10-CA30 prepared in Example 3, CD1-ESO10-CA60 prepared in Example 4, CD2-ESO10-CA60 prepared in Example 5, and CD5-ESO10-CA60 prepared in Example 6. DETAILED DESCRIPTION

[0019] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0020] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.

[0021] In some embodiments of the present invention, a modified epoxidized soybean oil is disclosed, which is obtained by reacting a cyclodextrin-epoxidized soybean oil inclusion compound with citric acid, wherein the cyclodextrin-epoxidized soybean oil inclusion compound is obtained by reacting cyclodextrin with epoxidized soybean oil.

[0022] In some embodiments, the cyclodextrin is β-cyclodextrin.

[0023] In some embodiments, the molar ratio of cyclodextrin, epoxidized soybean oil and citric acid is 0.1-0.5:1:3-9, preferably 0.1-0.5:1:3-6, and more preferably 0.2-0.5:1:3-6.

[0024] In other embodiments of the present invention, a method for preparing the modified epoxidized soybean oil is disclosed, comprising the following steps:

[0025] (1) reacting cyclodextrin and epoxidized soybean oil at 65° C. to 75° C. for 0.5 h to 1.5 h to obtain a cyclodextrin-epoxidized soybean oil inclusion complex;

[0026] (2) reacting the cyclodextrin-epoxidized soybean oil inclusion complex and citric acid at 65° C. to 75° C. for 2 h to 4 h;

[0027] (3) Add N,N-dimethylbenzylamine (BDMA) and react at 75°C to 85°C for 0.5h to 1.5h under vacuum to obtain the product.

[0028] In some embodiments, the reactions in steps (1) and (2) are carried out in the presence of water.

[0029] In some embodiments, the ratio of water to cyclodextrin in step (1) is 1 mL: 2 g to 12 g.

[0030] In some of the embodiments, the ratio of water to cyclodextrin in step (1) is 1 mL: 2.26 g to 11.3 g.

[0031] In some embodiments, the ratio of water to citric acid in step (2) is 1 mL: 3 g to 8 g.

[0032] In some embodiments, the ratio of water to citric acid in step (2) is 1 mL: 3.84 g to 7.68.

[0033] In some embodiments, the preparation method of the modified epoxidized soybean oil comprises the following steps:

[0034] (1) Cyclodextrin and water are stirred uniformly at 65° C. to 75° C., and then epoxidized soybean oil is added, reacted at 65° C. to 75° C. for 0.5 h to 1.5 h, and water is removed to obtain a cyclodextrin-epoxidized soybean oil inclusion complex;

[0035] (2) reacting the cyclodextrin-epoxidized soybean oil inclusion complex, water and citric acid at 65° C. to 75° C. for 2 h to 4 h to remove water;

[0036] (3) Add N,N-dimethylbenzylamine and react at 75°C to 85°C for 0.5h to 1.5h under vacuum to obtain the product.

[0037] In some embodiments, the reaction temperature in step (1) is 68°C to 72°C, more preferably 69°C to 71°C; and / or the reaction time is 0.8h to 1.2h, more preferably 0.9h to 1.1h.

[0038] In some embodiments, the reaction temperature in step (2) is 68°C to 72°C, more preferably 69°C to 71°C; and / or the reaction time is 2.5h to 3.5h, more preferably 2.8h to 3.2h.

[0039] In some embodiments, the reaction temperature in step (3) is 78°C to 82°C, more preferably 79°C to 81°C.

[0040] In some embodiments, the reaction time in step (3) is 0.8 h to 1.2 h.

[0041] In some embodiments, the reaction time in step (3) is 0.9 h to 1.1 h;

[0042] In some embodiments, the vacuum degree of the vacuum in step (3) is -0.08 MPa to -0.10 MPa.

[0043] In some of the embodiments, the vacuum degree of the vacuum in step (3) is -0.085 MPa to -0.095 MPa.

[0044] In other embodiments of the present invention, the use of the modified epoxidized soybean oil as a toughening agent in the preparation of epoxy resin adhesive is disclosed.

[0045] In some other embodiments of the present invention, an epoxy resin adhesive is disclosed, which is prepared from the following raw materials in parts by weight:

[0046]

[0047] In some embodiments, the epoxy resin adhesive is prepared from the following raw materials in parts by weight:

[0048]

[0049]

[0050] In some embodiments, the epoxy resin adhesive is prepared from the following raw materials in parts by weight:

[0051]

[0052] In some embodiments, the bisphenol A epoxy resin is one or more of E51, E54, and E44, preferably E51.

[0053] In some embodiments, the anhydride curing agent is one or more of methyltetrahydrophthalic anhydride, maleic anhydride, and phthalic anhydride, preferably methyltetrahydrophthalic anhydride.

[0054] In some embodiments, the curing accelerator is one or more of dimethylbenzylamine, dodecylammonium bromide, and DMP-30, preferably DMP-30.

[0055] In other embodiments of the present invention, a method for preparing the above-mentioned epoxy resin glue is disclosed, comprising the following steps: mixing bisphenol A epoxy resin, modified epoxy soybean oil, anhydride curing agent, and curing accelerator, stirring at a dispersion rate of 200rpm to 300rpm at 25°C to 35°C for 5min to 20min under vacuum conditions, and then curing at 95°C to 105°C for 2.5h to 3.5h.

[0056] In some embodiments, the vacuum degree is -0.08 MPa to -0.10 MPa, and more preferably -0.085 MPa to -0.095 MPa.

[0057] Unless otherwise specified, the examples are all based on conventional experimental conditions or the conditions recommended by the manufacturer's instructions. The sources of the epoxidized soybean oil, β-cyclodextrin, citric acid, N,N-dimethylbenzylamine, bisphenol A epoxy resin, curing agent, and curing accelerator described in the present invention are not particularly limited, and commercially available products known to those skilled in the art can be used. The raw materials used in the following examples of the present invention are all commercially available products.

[0058] In the following examples, modified epoxidized soybean oil was prepared using epoxidized soybean oil, β-cyclodextrin and citric acid as reaction raw materials, and the reaction process and principle are as follows:

[0059]

[0060] First, epoxidized soybean oil and β-cyclodextrin react to form an inclusion complex of epoxidized soybean oil encapsulated by β-cyclodextrin, and then the inclusion complex is reacted with citric acid in steps, wherein the carboxyl group in the citric acid first undergoes a ring-opening cross-linking reaction with the epoxy group in the epoxidized soybean oil molecule to form a cross-linked network, and then under the action of N,N-dimethylbenzylamine, the carboxyl group in the citric acid can further undergo an esterification reaction with the hydroxyl group on β-cyclodextrin, thereby grafting more citric acid on the inclusion complex, so that it contains more carboxyl groups. A structural diagram of the resulting modified epoxidized soybean oil is as follows:

[0061]

[0062] Among them, R1 represents a group containing epoxy soybean oil residues and citric acid residues formed by cross-linking an epoxy soybean oil molecule with another epoxy soybean oil molecule through citric acid, and R2 represents a group grafted onto cyclodextrin by esterification reaction of citric acid.

[0063] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] Example 1 Preparation of modified epoxidized soybean oil and epoxy resin glue

[0065] 1. Synthesis of cyclodextrin-epoxidized soybean oil inclusion complex

[0066] Weigh 11.3g (10mmol) of β-cyclodextrin into a 250mL round-bottom flask, add 5mL of deionized water, stir at 70℃ for 15min, add 100g (100mmol) of epoxidized soybean oil, stir at 70℃ for 1h to obtain a white emulsion. Remove water by vacuum distillation and dry in vacuo to obtain cyclodextrin-epoxidized soybean oil inclusion complex CD1-ESO10.

[0067] 2. Preparation of modified epoxidized soybean oil

[0068] Weigh 57.6g (300mmol) of citric acid in a 250mL round-bottom flask, add 15mL of deionized water and 111.3g of cyclodextrin-epoxidized soybean oil CD1-ESO10, and react at 70℃ for 3h. Remove water by vacuum distillation. Add 0.675g (5mmol) of N,N-dimethylbenzylamine (BDMA), and react at 80℃ for 1h under vacuum degree -0.09MPa. After the reaction, wash away the excess citric acid with water, and vacuum dry at 40℃ for 24h to obtain modified epoxidized soybean oil CD1-ESO10-CA30.

[0069] Adding the prepared modified epoxidized soybean oil into the epoxy resin system to prepare the epoxy resin glue comprises the following steps:

[0070] 40g of bisphenol A epoxy resin E51, 10g of modified epoxy soybean oil CD1-ESO10-CA30, 49.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 were mixed in a sample jar, and stirred in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, it was applied to a polytetrafluoroethylene mold and cured at 100°C for 3h to obtain the obtained product.

[0071] Example 2 Preparation of modified epoxidized soybean oil and epoxy resin glue

[0072] 1. Synthesis of cyclodextrin-epoxidized soybean oil inclusion complex

[0073] Weigh 22.6g (20mmol) of β-cyclodextrin into a 250mL round-bottom flask, add 5mL of deionized water, stir at 70℃ for 15min, add 100g (100mmol) of epoxidized soybean oil, stir at 70℃ for 1h to obtain a white emulsion. Remove water by vacuum distillation and dry in vacuum to obtain cyclodextrin-epoxidized soybean oil inclusion complex CD2-ESO10.

[0074] 2. Preparation of modified epoxidized soybean oil

[0075] Weigh 57.6g (300mmol) of citric acid into a 250mL round-bottom flask, add 15mL of deionized water and 122.6g of cyclodextrin-epoxidized soybean oil CD2-ESO10, and react at 70℃ for 3h. Remove water by vacuum distillation. Add 0.675g (5mmol) of N,N-dimethylbenzylamine (BDMA), vacuum degree -0.09MPa, and react at 80℃ for 1h. After the reaction, wash away the excess citric acid with water, and vacuum dry at 40℃ for 24h to obtain modified epoxidized soybean oil CD2-ESO10-CA30.

[0076] 3. Preparation of epoxy resin glue

[0077] 40g of bisphenol A epoxy resin E51, 10g of modified epoxy soybean oil CD2-ESO10-CA30, 49.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 were mixed in a sample tank, and stirred in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, it was applied to a polytetrafluoroethylene mold and cured at 100°C for 3h to obtain the obtained product.

[0078] Example 3 Preparation of modified epoxidized soybean oil and epoxy resin glue

[0079] 1. Synthesis of cyclodextrin-epoxidized soybean oil inclusion complex

[0080] Weigh 56.5g (50mmol) of β-cyclodextrin into a 250mL round-bottom flask, add 5mL of deionized water, stir at 70℃ for 15min, add 100g (100mmol) of epoxidized soybean oil, stir at 70℃ for 1h to obtain a white emulsion. Remove water by vacuum distillation and dry in vacuo to obtain cyclodextrin-epoxidized soybean oil inclusion complex CD5-ESO10.

[0081] 2. Preparation of modified epoxidized soybean oil

[0082] Weigh 57.6g (300mmol) of citric acid into a 250mL round-bottom flask, add 15mL of deionized water and 156.5g of cyclodextrin-epoxidized soybean oil CD5-ESO10, and react at 70℃ for 3h. Remove water by vacuum distillation. Add 0.675g (5mmol) of N,N-dimethylbenzylamine (BDMA), vacuum degree -0.09MPa, and react at 80℃ for 1h. After the reaction, wash away the excess citric acid with water, and vacuum dry at 40℃ for 24h to obtain modified epoxidized soybean oil CD5-ESO10-CA30.

[0083] 3. Preparation of epoxy resin glue

[0084] 40g of bisphenol A epoxy resin E51, 10g of modified epoxy soybean oil CD5-ESO10-CA30, 49.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 were mixed in a sample tank, and stirred in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, it was applied to a polytetrafluoroethylene mold and cured at 100°C for 3h to obtain the obtained product.

[0085] Example 4 Preparation of modified epoxidized soybean oil and epoxy resin glue

[0086] 1. Synthesis of cyclodextrin-epoxidized soybean oil inclusion complex

[0087] Weigh 11.3g (10mmol) of β-cyclodextrin into a 250mL round-bottom flask, add 5mL of deionized water, stir at 70℃ for 15min, add 100g (100mmol) of epoxidized soybean oil, stir at 70℃ for 1h to obtain a white emulsion. Remove water by vacuum distillation and dry in vacuo to obtain cyclodextrin-epoxidized soybean oil inclusion complex CD1-ESO10.

[0088] 2. Preparation of modified epoxidized soybean oil

[0089] Weigh 115.2g (600mmol) of citric acid into a 250mL round-bottom flask, add 15mL of deionized water and 111.3g of cyclodextrin-epoxidized soybean oil CD1-ESO10, and react at 70℃ for 3h. Remove water by vacuum distillation. Add 0.675g (5mmol) of N,N-dimethylbenzylamine (BDMA), vacuum degree -0.09MPa, and react at 80℃ for 1h. After the reaction, wash away the excess citric acid with water, and vacuum dry at 40℃ for 24h to obtain modified epoxidized soybean oil CD1-ESO10-CA60.

[0090] 3. Preparation of epoxy resin glue

[0091] 40g of bisphenol A epoxy resin E51, 10g of modified epoxy soybean oil CD1-ESO10-CA60, 49.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 were mixed in a sample tank, and stirred in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, it was applied to a polytetrafluoroethylene mold and cured at 100°C for 3h to obtain the obtained product.

[0092] Example 5 Preparation of modified epoxidized soybean oil and epoxy resin glue

[0093] 1. Synthesis of cyclodextrin-epoxidized soybean oil inclusion complex

[0094] Weigh 22.6g (20mmol) of β-cyclodextrin into a 250mL round-bottom flask, add 5mL of deionized water, stir at 70℃ for 15min, add 100g (100mmol) of epoxidized soybean oil, stir at 70℃ for 1h to obtain a white emulsion. Remove water by vacuum distillation and dry in vacuum to obtain cyclodextrin-epoxidized soybean oil inclusion complex CD2-ESO10.

[0095] 2. Preparation of modified epoxidized soybean oil

[0096] Weigh 115.2g (600mmol) of citric acid in a 250mL round-bottom flask, add 15mL of deionized water and 122.6g of cyclodextrin-epoxidized soybean oil CD2-ESO10, and react at 70℃ for 3h. Remove water by vacuum distillation. Add 0.675g (5mmol) of N,N-dimethylbenzylamine (BDMA), vacuum degree -0.09MPa, and react at 80℃ for 1h. After the reaction, wash away the excess citric acid with water, and vacuum dry at 40℃ for 24h to obtain modified epoxidized soybean oil CD2-ESO10-CA60.

[0097] 3. Preparation of epoxy resin glue

[0098] 40g of bisphenol A epoxy resin E51, 10g of modified epoxy soybean oil CD2-ESO10-CA60, 49.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 were mixed in a sample tank, and stirred in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, it was applied to a polytetrafluoroethylene mold and cured at 100°C for 3h to obtain the obtained product.

[0099] Example 6 Preparation of modified epoxidized soybean oil and epoxy resin glue

[0100] 1. Synthesis of cyclodextrin-epoxidized soybean oil inclusion complex

[0101] Weigh 56.5g (50mmol) of β-cyclodextrin into a 250mL round-bottom flask, add 5mL of deionized water, stir at 70℃ for 15min, add 100g (100mmol) of epoxidized soybean oil, stir at 70℃ for 1h to obtain a white emulsion. Remove water by vacuum distillation and dry in vacuo to obtain cyclodextrin-epoxidized soybean oil inclusion complex CD5-ESO10.

[0102] 2. Preparation of modified epoxidized soybean oil

[0103] Weigh 115.2g (600mmol) of citric acid in a 250mL round-bottom flask, add 15mL of deionized water and 156.5g of cyclodextrin-epoxidized soybean oil CD5-ESO10, and react at 70℃ for 3h. Remove water by vacuum distillation. Add 0.675g (5mmol) of N,N-dimethylbenzylamine (BDMA), vacuum degree -0.09MPa, and react at 80℃ for 1h. After the reaction, wash away the excess citric acid with water, and vacuum dry at 40℃ for 24h to obtain modified epoxidized soybean oil CD5-ESO10-CA60.

[0104] 3. Preparation of epoxy resin glue

[0105] 40g of bisphenol A epoxy resin E51, 10g of modified epoxy soybean oil CD5-ESO10-CA60, 49.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 were mixed in a sample tank, and stirred in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, it was applied to a polytetrafluoroethylene mold and cured at 100°C for 3h to obtain the obtained product.

[0106] Example 7 Preparation of modified epoxidized soybean oil and epoxy resin glue

[0107] 1. Synthesis of cyclodextrin-epoxidized soybean oil inclusion complex

[0108] Same as Example 1.

[0109] 2. Preparation of modified epoxidized soybean oil

[0110] Same as Example 1.

[0111] 3. Preparation of epoxy resin glue

[0112] 35g of bisphenol A epoxy resin E51, 15g of modified epoxy soybean oil CD1-ESO10-CA30, 49.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 were mixed in a sample tank, and stirred in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, it was applied to a polytetrafluoroethylene mold and cured at 100°C for 3h to obtain the obtained product.

[0113] Example 8 Preparation of modified epoxidized soybean oil and epoxy resin glue

[0114] 1. Synthesis of cyclodextrin-epoxidized soybean oil inclusion complex

[0115] Same as Example 1.

[0116] 2. Preparation of modified epoxidized soybean oil

[0117] Same as Example 1.

[0118] 3. Preparation of epoxy resin glue

[0119] 40g of bisphenol A epoxy resin E51, 15g of modified epoxy soybean oil CD1-ESO10-CA30, 44.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 were mixed in a sample tank, and stirred in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, it was applied to a polytetrafluoroethylene mold and cured at 100°C for 3h to obtain the obtained product.

[0120] Comparative Example 1 Preparation of epoxy resin glue

[0121] Mix 50g of bisphenol A epoxy resin E51, 49.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 in a sample jar, and stir in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, apply it to a polytetrafluoroethylene mold and cure it at 100°C for 3h to obtain the product.

[0122] Comparative Example 2 Preparation of epoxy resin glue

[0123] Mix 55g of bisphenol A epoxy resin E51, 44.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 in a sample jar, and stir in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, apply it to a polytetrafluoroethylene mold and cure it at 100°C for 3h to obtain the product.

[0124] Comparative Example 3 Preparation of epoxy resin glue

[0125] 40g of bisphenol A epoxy resin E51, 10g of epoxy soybean oil, 49.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 were mixed in a sample jar, and stirred in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, it was applied to a polytetrafluoroethylene mold and cured at 100°C for 3h to obtain the product.

[0126] Comparative Example 4 Preparation of epoxy resin glue

[0127] Mix 45g of bisphenol A epoxy resin E51, 10g of epoxy soybean oil, 44.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 in a sample jar, and stir in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, apply it to a polytetrafluoroethylene mold and cure it at 100°C for 3h to obtain the product.

[0128] Comparative Example 5

[0129] 40g of bisphenol A epoxy resin E51, 10g of cyclodextrin-epoxidized soybean oil inclusion compound (prepared by the same method as in Example 1), 49.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 were mixed in a sample jar, and stirred in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, the mixture was applied to a polytetrafluoroethylene mold and cured at 100°C for 3h to obtain the obtained product.

[0130] Comparative Example 6

[0131] 1. Preparation of modified epoxidized soybean oil

[0132] Weigh 57.6g (300mmol) of citric acid in a 250mL round-bottom flask, add 15mL of deionized water and 100g (100mmol) of epoxidized soybean oil, and react at 70℃ for 3h. Remove water by vacuum distillation. Add 0.675g (5mmol) of N,N-dimethylbenzylamine (BDMA), and react at 80℃ for 1h under vacuum degree -0.09MPa. After the reaction, wash away the excess citric acid with water, and vacuum dry at 40℃ for 24h to obtain modified epoxidized soybean oil ESO10-CA30.

[0133] 2. Preparation of epoxy resin glue

[0134] 40g of bisphenol A epoxy resin E51, 15g of modified epoxy soybean oil ESO10-CA30, 44.5g of methyltetrahydrophthalic anhydride, and 0.5g of DMP-30 were mixed in a sample jar, and stirred in a high-speed disperser at a vacuum degree of -0.09MPa, 30°C, and a dispersion rate of 200rpm for 15min. After mixing evenly, it was applied to a polytetrafluoroethylene mold and cured at 100°C for 3h to obtain the obtained product.

[0135] Figure 1 The infrared absorption spectra (FTIR) of unmodified epoxidized soybean oil, CD1-ESO10-CA30 prepared in Example 1, CD2-ESO10-CA30 prepared in Example 2, CD5-ESO10-CA30 prepared in Example 3, CD1-ESO10-CA60 prepared in Example 4, CD2-ESO10-CA60 prepared in Example 5, and CD5-ESO10-CA60 prepared in Example 6 are shown in FIG. Figure 1 It can be seen that with the increase of citric acid content in modified epoxidized soybean oil, the -1 The ester peak at 1460 cm-1 gradually broadens to a shoulder peak. -1 The CH bending vibration peak at 1025cm also gradually changes from a sharp peak to a flat peak, indicating that the epoxy groups in the epoxidized soybean oil are ring-opened under the action of citric acid and the degree of polymerization of the system is increased. -1 The intensity of the peak gradually increases, which is due to the hydroxyl groups generated by the ring opening of epoxidized soybean oil and the hydroxyl groups of cyclodextrin.

[0136] Table 1 shows the component selection and proportion of the embodiments and comparative examples. The following performance tests were conducted on the epoxy resin adhesives of the embodiments and comparative examples (curing conditions: 80°C, 6h):

[0137] 1. Tensile strength and elongation at break: GB / T 528-2009, Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber.

[0138] 2. Impact strength: GB / T 2567-2008, Test method for properties of resin castings.

[0139] The test results are shown in Table 2.

[0140] Table 1

[0141]

[0142] Note: The amount of each component in Table 1 is by weight. a in Comparative Example 5 represents cyclodextrin-epoxidized soybean oil inclusion compound (CD1-ESO10), and b in Comparative Example 6 represents citric acid modified epoxy soybean oil (ESO10-CA30).

[0143] Table 2

[0144]

[0145]

[0146] From the results in Table 2, it can be seen that compared with the epoxy resin glue prepared without epoxy soybean oil (Comparative Examples 1-2), the epoxy resin glue prepared by adding epoxy soybean oil to the epoxy resin system (Comparative Examples 3-4) has improved tensile strength, elongation at break, and normal and low temperature impact strength. Compared with the epoxy resin glue prepared by unmodified epoxy soybean oil (Comparative Examples 3-4), the mechanical properties of the epoxy resin glue prepared by cyclodextrin-modified epoxy soybean oil (Comparative Example 5) have no obvious improvement, while the mechanical properties and tensile properties of the epoxy resin glue prepared by citric acid-modified epoxy soybean oil (Comparative Example 6) are improved. The epoxy resin glue prepared by adding the modified epoxy soybean oil prepared by the present invention has significantly better tensile strength, elongation at break, impact strength and low temperature impact strength (Examples 1-8), indicating that the epoxy soybean oil modified by cyclodextrin and citric acid has a significant toughening effect on the epoxy resin glue, and can significantly improve the mechanical properties and tensile properties of the epoxy resin glue.

[0147] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0148] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A modified epoxidized soybean oil, characterized in that: The cyclodextrin-epoxidized soybean oil inclusion compound is obtained by reacting cyclodextrin and epoxidized soybean oil. The cyclodextrin-epoxidized soybean oil inclusion compound is obtained by reacting cyclodextrin and epoxidized soybean oil.

2. The modified epoxidized soybean oil according to claim 1, characterized in that The cyclodextrin is β-cyclodextrin; and / or the molar ratio of the cyclodextrin, epoxidized soybean oil and citric acid is 0.1-0.5:1:3-9, preferably 0.1-0.5:1:3-6, and more preferably 0.2-0.5:1:3-6.

3. A method for preparing the modified epoxidized soybean oil according to claim 1 or 2, characterized in that: The following steps are involved: (1) reacting cyclodextrin and epoxidized soybean oil at 65° C. to 75° C. for 0.5 h to 1.5 h to obtain a cyclodextrin-epoxidized soybean oil inclusion complex; (2) reacting the cyclodextrin-epoxidized soybean oil inclusion complex and citric acid at 65° C. to 75° C. for 2 h to 4 h; (3) Add N,N-dimethylbenzylamine and react at 75°C to 85°C for 0.5h to 1.5h under vacuum to obtain the product.

4. The method for preparing modified epoxidized soybean oil according to claim 3, characterized in that: The reactions in steps (1) and (2) are carried out in the presence of water; the ratio of water to cyclodextrin in step (1) is 1 mL: 2 g to 12 g, preferably 1 mL: 2.26 g to 11.3 g; the ratio of water to citric acid in step (2) is 1 mL: 3 g to 8 g, preferably 1 mL: 3.84 g to 7.68 g; Preferably, the method for preparing the modified epoxidized soybean oil comprises the following steps: (1) Cyclodextrin and water are stirred uniformly at 65° C. to 75° C., and then epoxidized soybean oil is added, reacted at 65° C. to 75° C. for 0.5 h to 1.5 h, and water is removed to obtain a cyclodextrin-epoxidized soybean oil inclusion complex; (2) reacting the cyclodextrin-epoxidized soybean oil inclusion complex, water and citric acid at 65° C. to 75° C. for 2 h to 4 h to remove water; (3) Add N,N-dimethylbenzylamine and react at 75°C to 85°C for 0.5h to 1.5h under vacuum to obtain the product.

5. The method for preparing modified epoxidized soybean oil according to claim 3 or 4, characterized in that: The reaction temperature in step (1) is 68°C to 72°C, more preferably 69°C to 71°C; the reaction time is 0.8h to 1.2h, more preferably 0.9h to 1.1h; And / or, the reaction temperature in step (2) is 68°C to 72°C, more preferably 69°C to 71°C; the reaction time is 2.5h to 3.5h, more preferably 2.8h to 3.2h; And / or, the reaction temperature in step (3) is 78°C to 82°C, more preferably 79°C to 81°C; the reaction time is 0.8h to 1.2h, more preferably 0.9h to 1.1h; And / or, the vacuum degree of the vacuum in step (3) is -0.08 MPa to -0.10 MPa, preferably -0.085 MPa to -0.095 MPa.

6. Use of the modified epoxidized soybean oil according to claim 1 or 2 as a toughening agent in the preparation of epoxy resin adhesive.

7. An epoxy resin adhesive, characterized in that: It is prepared from the following raw materials in parts by weight:

8. The epoxy resin adhesive according to claim 7, characterized in that: It is prepared from the following raw materials in parts by weight: Preferably, it is prepared from the following raw materials in parts by weight:

9. The epoxy resin adhesive according to claim 7 or 8, characterized in that: The bisphenol A epoxy resin is one or more of E51, E54, and E44, preferably E51; And / or, the acid anhydride curing agent is one or more of methyltetrahydrophthalic anhydride, maleic anhydride, and phthalic anhydride, preferably methyltetrahydrophthalic anhydride; And / or, the curing accelerator is one or more of dimethylbenzylamine, dodecylammonium bromide, and DMP-30, preferably DMP-30.

10. A method for preparing the epoxy resin adhesive according to any one of claims 7 to 9, characterized in that: The following steps are involved: Mix bisphenol A epoxy resin, modified epoxy soybean oil, anhydride curing agent and curing accelerator, stir at 25°C to 35°C at a dispersion rate of 200rpm to 300rpm for 5min to 20min under vacuum, and then cure at 95°C to 105°C for 2.5h to 3.5h to obtain the product.

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