Organic silicon resin toughening agent, single-component high-strength epoxy structural adhesive, and preparation methods for both

Abstract

An organic silicon resin toughening agent, a single-component high-strength epoxy structural adhesive, and preparation methods for both. The organic silicon resin toughening agent is prepared by reacting epoxy modified hydrogen-containing silicone oil and vinyl six-membered cyclic oligomeric silsesquioxane; and the epoxy modified hydrogen-containing silicone oil is prepared by reacting allyl alcohol glycidyl ether and hydrogen-containing silicone oil which contains hydrogen at both ends. Compared with toughening agents such as nitrile rubber and core-shell structured rubber, the synthesized organic silicon resin toughening agent having a cyclic mesh structure unit in the present invention has better high and low temperature resistance, and can significantly improve the high and low temperature resistance of the single-component high-strength epoxy structural adhesive while improving the toughness of the single-component high-strength epoxy structural adhesive.

Description

Silicone resin toughening agent, single-component high-strength epoxy structural adhesive and preparation method thereof

[0001] The present invention claims priority to the Chinese patent application filed with the Patent Office of China on August 21, 2023, with application number 2023110540471, entitled “A silicone resin toughening agent, a one-component high-strength epoxy structural adhesive and a preparation method thereof”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present invention relates to the field of adhesives, and in particular to a silicone resin toughening agent, a single-component high-strength epoxy structural adhesive and a preparation method thereof. Background Art

[0003] Epoxy structural adhesives offer advantages such as high bond strength and a wide range of applications. In the automotive industry, they are widely used to bond structural parts and components in vehicle bodies, improving vehicle strength while reducing overall vehicle weight. However, untoughened epoxy adhesives are brittle, exhibit poor impact resistance, and exhibit low peel strength. While toughening agents such as nitrile rubber and core-shell rubber can improve the toughness of epoxy structural adhesives, they also reduce their heat resistance.

[0004] Summary of the Invention

[0005] In order to overcome the above problems, the present invention synthesizes an organic silicone resin toughening agent with excellent high and low temperature resistance, which can be used for toughening modification of epoxy resin, thereby improving the toughness and high and low temperature resistance of epoxy resin.

[0006] The organosilicon resin toughening agent of the present invention includes the following technical solutions:

[0007] A silicone resin toughening agent, the structural formula of which is:

[0008] Among them, 50≤n≤300.

[0009] In some embodiments, 100≤n≤150.

[0010] A silicone resin toughening agent, prepared by reacting epoxy-modified hydrogenated silicone oil and vinyl six-membered cyclic oligomeric silsesquioxane; the epoxy-modified hydrogenated silicone oil is prepared by reacting allyl alcohol glycidyl ether and hydrogenated silicone oil containing hydrogen at both ends;

[0011] The structural formula of the vinyl hexacyclic oligomeric silsesquioxane is:

[0012] In some embodiments, the molar ratio of allyl alcohol glycidyl ether, hydrogen-containing silicone oil, and vinyl six-membered cyclic oligomeric silsesquioxane is 5-7:5-7:1.

[0013] In some embodiments, the molar ratio of allyl alcohol glycidyl ether, hydrogen-containing silicone oil, and vinyl six-membered cyclic oligomeric silsesquioxane is 6:6:1.

[0014] In some embodiments, the hydrogen-containing silicone oil is a hydrogen-containing silicone oil containing hydrogen at both ends and having a hydrogen content of 0.09 mmol / g-0.52 mmol / g.

[0015] In some embodiments, the hydrogen-containing silicone oil is a hydrogen-containing silicone oil containing hydrogen at both ends and having a hydrogen content of 0.15 mmol / g-0.25 mmol / g.

[0016] In some embodiments, the vinyl six-membered cyclic oligomeric silsesquioxane is obtained by reacting a potassium hexavinylcyclohexasilanol / copper salt complex with trimethylchlorosilane; and the potassium hexavinylcyclohexasilanol / copper salt complex is obtained by reacting vinyltrimethoxysilane with a base and then with copper chloride dihydrate.

[0017] In some embodiments, the mass ratio of the potassium hexavinylcyclohexasiliconate / copper salt complex to trimethylchlorosilane is 1:1-1.5.

[0018] In some embodiments, the mass ratio of the vinyltrimethoxysilane, the base and the cupric chloride dihydrate is 1:0.4-0.5:0.3-0.4.

[0019] In some embodiments, the base is sodium hydroxide and / or potassium hydroxide.

[0020] In some embodiments, the method for preparing the vinyl hexacyclic oligomeric silsesquioxane comprises the following steps:

[0021] The first step is to dissolve the vinyltrimethoxysilane in methanol, then add a base, stir evenly, heat and reflux for 20 minutes to 30 minutes, add a methanol solution containing copper chloride dihydrate, reflux for 20 minutes to 30 minutes, filter out the potassium chloride salt after cooling, and refrigerate the mixture at 5°C to 10°C to obtain hexavinylcyclohexasiliconol potassium / copper salt complex crystals;

[0022] Step 2: adding potassium hexavinylcyclohexasilane / copper salt complex crystals and n-hexane solvent into a reaction vessel, adding n-hexane solution containing trimethylchlorosilane dropwise into the reaction vessel, stirring, reflux reaction for 8 hours to 16 hours, and post-treating to obtain the vinyl hexacyclic oligomeric silsesquioxane.

[0023] The present invention also provides a method for preparing the organosilicon resin toughening agent, which includes the following technical solutions.

[0024] A method for preparing a silicone resin toughening agent comprises the following steps:

[0025] The hydrogenated silicone oil and an appropriate amount of Pt catalyst are added to a reactor, stirred evenly, and the allyl alcohol glycidyl ether is added dropwise. After the addition is complete, the mixture is reacted at a temperature of 40° C. to 60° C. for 1 to 2 hours to obtain the epoxy-modified hydrogenated silicone oil.

[0026] The epoxy-modified hydrogenated silicone oil and the vinyl six-membered cyclic oligomeric silsesquioxane are reacted at 50° C. to 70° C. under the action of a Pt catalyst for 1 to 2 hours to prepare the silicone resin toughening agent.

[0027] The present invention also provides a one-component, high-strength epoxy structural adhesive for bonding automobile bodies and a method for preparing the same. The one-component, high-strength epoxy structural adhesive prepared by the present invention exhibits excellent toughness and high and low-temperature resistance, as well as excellent adhesion to metal materials such as steel and aluminum, making it particularly suitable for structural bonding applications in the automotive field.

[0028] The one-component high-strength epoxy structural adhesive of the present invention includes the following technical solutions.

[0029] A single-component high-strength epoxy structural adhesive is prepared from the following raw materials in parts by weight:

[0030] In some embodiments, the one-component high-strength epoxy structural adhesive is prepared from raw materials including the following components, in parts by weight:

[0031] In some embodiments, the one-component high-strength epoxy structural adhesive is prepared from raw materials including the following components, in parts by weight:

[0032] In some embodiments, the epoxy resin is selected from any one or more combinations of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, castor oil-modified epoxy resin, polyurethane-modified epoxy resin, silicone-modified epoxy resin, and acrylate-modified epoxy resin.

[0033] In some embodiments, the filler is selected from one or more combinations of nano calcium carbonate, heavy calcium carbonate, silica powder, fumed silica, alumina, aluminum hydroxide, talc, and bentonite.

[0034] In some embodiments, the filler is selected from a combination of fumed silica and nano-calcium carbonate in a ratio of 1:9-10.

[0035] In some embodiments, the curing agent is dicyandiamide or hydrazide.

[0036] In some embodiments, the accelerator is selected from any one or more combinations of substituted urea, imidazole, and imidazole derivatives.

[0037] The present invention also provides a method for preparing the single-component high-strength epoxy structural adhesive, which includes the following technical solutions.

[0038] A method for preparing a one-component high-strength epoxy structural adhesive comprises the following steps: mixing the epoxy resin, an organosilicon resin toughening agent, a filler, a curing agent and an accelerator, and stirring them uniformly to obtain the one-component high-strength epoxy structural adhesive.

[0039] The present invention synthesizes an organic silicone resin toughening agent containing epoxy groups and a ring-shaped network structure using allyl glycidyl ether, hydrogenated silicone oil, and vinyl hexacyclic oligomeric silsesquioxane as raw materials. This toughening agent is then used to prepare a one-component, high-strength epoxy structural adhesive. Compared to existing technologies, the organic silicone resin toughening agent and one-component, high-strength epoxy structural adhesive of the present invention exhibit the following beneficial effects:

[0040] The synthesized silicone resin toughening agent contains multiple reactive epoxy groups. When used in one-component, high-strength epoxy structural adhesives for vehicle bodies, the presence of these epoxy groups helps improve the compatibility between silicone and epoxy resin systems. Furthermore, from a microscopic perspective, during colloid curing, the siloxane and epoxy segments exhibit a certain degree of incompatibility, easily forming a microphase-separated sea-island structure, thereby effectively enhancing the strength and toughness of the epoxy structural adhesive.

[0041] 2. The organic silicone resin toughening agent with annular network structure units synthesized by the present invention has better high and low temperature resistance than toughening agents such as nitrile rubber and core-shell structure rubber. While improving the toughness of single-component high-strength epoxy structural adhesive, it can significantly improve the high and low temperature resistance of single-component high-strength epoxy structural adhesive. DETAILED DESCRIPTION

[0042] The technical solutions of the present invention are further illustrated by specific examples below. Those skilled in the art should understand that the examples are only for helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0043] 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. 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.

[0044] The terms "comprise," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or device comprising a series of steps is not limited to the listed steps or modules but may optionally include steps not listed, or other steps inherent to the process, method, product, or device.

[0045] In this application, "plurality" refers to two or more. "And / or" describes the relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone. The character " / " generally indicates that the related objects are in an "or" relationship.

[0046] The preparation method of the organosilicon resin toughening agent of the present invention is as follows:

[0047] a. Weigh a certain amount of hydrogenated silicone oil (hydrogen content of 0.09mmol / g-0.52mmol / g, corresponding to 50≤n≤300) and an appropriate amount of Custer platinum catalyst, add them to the reactor and stir evenly. Slowly and uniformly add an equal molar amount of allyl alcohol glycidyl ether dropwise over 2-3 hours. After the addition is complete, react at 50°C for 1.5 hours to obtain epoxy-modified hydrogenated silicone oil. The reaction principle is as follows:

[0048] The epoxy modified hydrogenated silicone oil was analyzed by FT-IR spectrum, and the results showed that the -1 The characteristic stretching vibration peak of Si-O-Si appears at 915cm -1 The characteristic peak with higher intensity and sharper shape at 2160cm should be attributed to the stretching vibration peak of CO of epoxy group. -1 The characteristic peak of 1650cm belongs to the characteristic absorption peak of Si-H. -1 No C=C characteristic peak was found nearby, indicating that an addition reaction occurred between the hydrogenated silicone oil and allyl alcohol glycidyl ether.

[0049] b. Vinyl six-membered cyclic oligomeric silsesquioxane is prepared by two steps:

[0050] The first step is to dissolve 100g of vinyltrimethoxysilane in 600ml of methanol, then add 45g of potassium hydroxide, stir evenly, heat and reflux for 15-20 minutes, add 100ml of methanol solution containing 38g of copper chloride dihydrate, and reflux for 25-30 minutes. After cooling to room temperature (25°C), filter out the potassium chloride salt and refrigerate the mixture in a refrigerator (10°C). After 2 hours, blue crystals of hexavinylcyclohexasilane potassium / copper salt complex {K2[(ViSiO2)6K2CuO4(O2SiVi)6]}.5(CH3OH) are obtained. FT-IR spectral analysis shows that the hexavinylcyclohexasilane potassium / copper salt complex has a blue crystal structure at 3053cm -1 and 2951cm -1 The stretching vibration peak of vinyl CH appears at 990 cm -1 The characteristic peak at 3416 cm is the out-of-plane deformation vibration peak of vinyl CH. -1 The broad peak at 1100 cm-1 is the OH stretching peak caused by the intermolecular oxygen bond between water and alcohol molecules in the crystal. -1 (Si-O, CO) stretching vibration peaks at .

[0051] Step 2: Add 30g of potassium hexavinylcyclohexasilane / copper salt and 200g of n-hexane solvent to a three-necked flask at once. Dissolve 38.6g of trimethylchlorosilane in 100ml of n-hexane and add dropwise to the flask. Stir vigorously and reflux for 12 hours. Cool to room temperature and filter. Wash the filtrate with water until neutral, dry with anhydrous sodium sulfate, filter, and remove the solvent by rotary evaporation to obtain a colorless, transparent oily vinyl hexacyclic oligomeric silsesquioxane. FT-IR spectral analysis revealed that the 1103cm -1 The Si-O-Si characteristic stretching vibration peak appears at 1652m -1 The characteristic peak at 2962cm belongs to the characteristic absorption peak of C=C. -1 The characteristic peak at 1251 cm is the antisymmetric stretching vibration peak of the CH of the methyl group in -Si(CH3)3. -1 and 845cm -1 The characteristic peaks are the symmetrical deformation vibration peaks and in-plane rocking vibration peaks of Si-CH3 in -Si(CH3)3. The appearance of the -Si(CH3) vibration peak indicates that potassium hexavinylcyclohexasilane / copper salt reacted with trimethylchlorosilane, and the metal ions in the complex crystal were successfully stripped off.

[0052] c. The epoxy-modified hydrogenated silicone oil obtained in step a and the vinyl hexacyclic oligomeric silsesquioxane obtained in step b were added to the reactor in a molar ratio of 6:1, an appropriate amount of Custer platinum catalyst was added, stirred evenly, and reacted at 60°C for 1.5h to obtain a silicone resin toughening agent.

[0053] The reaction principle is as follows:

[0054] The obtained silicone resin toughening agent was subjected to FT-IR spectrum analysis and it was found that -1 The characteristic stretching vibration peak of Si-O-Si appears at 2962cm -1 The characteristic peak at 1251 cm is the antisymmetric stretching vibration peak of the CH of the methyl group in -Si(CH3)3. -1 and 845cm -1 The characteristic peaks at 910 cm are the symmetrical deformation vibration peak and in-plane rocking vibration peak of Si-CH3 in -Si(CH3)3. -1 The high intensity and sharp peak at 2160 cm-1 should be attributed to the stretching vibration peak of CO of the epoxy group. -1 The characteristic absorption peaks of Si-H at 1652 cm -1 The C=C characteristic peak at the position disappears, indicating that the silicone resin toughening agent with the above structure is obtained.

[0055] Example 1

[0056] The single-component high-strength epoxy structural adhesive provided in this embodiment is prepared from the following components in parts by weight:

[0057] In the preparation process of the organic silicone resin toughening agent, hydrogen-containing silicone oil (ie, n is 133) with a hydrogen content of 0.2 mmol / g and hydrogen at both ends is used.

[0058] The preparation method is as follows: the bisphenol A diglycidyl ether epoxy resin, silicone resin toughening agent, nano calcium carbonate, fumed silica, dicyandiamide curing agent, and substituted urea accelerator are mixed and stirred evenly, and the material is discharged to obtain the single-component high-strength epoxy structural adhesive.

[0059] Example 2

[0060] The single-component high-strength epoxy structural adhesive provided in this embodiment is prepared from the following components in parts by weight:

[0061] The silicone resin toughening agent is prepared using a hydrogen-containing silicone oil (i.e., n is 52) with a hydrogen content of 0.5 mmol / g and hydrogen at both ends.

[0062] The preparation method is as follows: the bisphenol A diglycidyl ether epoxy resin, silicone resin toughening agent, nano calcium carbonate, dicyandiamide curing agent, and substituted urea accelerator are mixed and stirred evenly, and the material is discharged to obtain the single-component high-strength epoxy structural adhesive.

[0063] Example 3

[0064] The single-component high-strength epoxy structural adhesive provided in this embodiment is prepared from the following components in parts by weight:

[0065] The silicone resin toughening agent was prepared using a hydrogenated silicone oil (n = 133) with a hydrogen content of 0.2 mmol / g at both ends. Dow DER791 polyurethane-modified epoxy resin has an epoxy equivalent weight of 235-270 and a viscosity of 35,000-45,000 cps at 25°C.

[0066] The preparation method is as follows: the polyurethane modified epoxy resin, silicone resin toughening agent, nano calcium carbonate, dicyandiamide curing agent and substituted urea accelerator are mixed and stirred evenly, and the material is discharged to obtain the single-component high-strength epoxy structural adhesive.

[0067] Example 4

[0068] The single-component high-strength epoxy structural adhesive provided in this embodiment is prepared from the following components in parts by weight:

[0069] In the preparation process of the organic silicone resin toughening agent, hydrogen-containing silicone oil (ie, n is 268) with a hydrogen content of 0.1 mmol / g and hydrogen at both ends is used.

[0070] The preparation method is as follows: the bisphenol F diglycidyl ether, silicone resin toughening agent, silicon powder, dicyandiamide curing agent, and substituted urea accelerator are mixed and stirred evenly, and the material is discharged to obtain the single-component high-strength epoxy structural adhesive.

[0071] Example 5

[0072] The single-component high-strength epoxy structural adhesive provided in this embodiment is prepared from the following components in parts by weight:

[0073] In the preparation process of the organic silicone resin toughening agent, hydrogen-containing silicone oil (ie, n is 88) with a hydrogen content of 0.3 mmol / g and hydrogen at both ends is used.

[0074] The preparation method is as follows: the bisphenol F diglycidyl ether, silicone resin toughening agent, nano calcium carbonate, fumed silica, dicyandiamide curing agent, and substituted urea accelerator are mixed and stirred evenly, and the material is discharged to obtain the single-component high-strength epoxy structural adhesive.

[0075] Comparative Example 1

[0076] The single-component high-strength epoxy structural adhesive provided in this comparative example is prepared from the following components in parts by weight:

[0077] The preparation method is as follows: the bisphenol A diglycidyl ether, nano calcium carbonate, fumed silica, dicyandiamide curing agent and substituted urea accelerator are mixed and stirred evenly, and the material is discharged to obtain the single-component high-strength epoxy structural adhesive.

[0078] Comparative Example 2

[0079] The single-component high-strength epoxy structural adhesive provided in this comparative example is prepared from the following components in parts by weight:

[0080] The preparation method is as follows: the bisphenol A diglycidyl ether, CTBN toughening agent, nano calcium carbonate, fumed silica, dicyandiamide curing agent, and substituted urea accelerator are mixed and stirred evenly, and the material is discharged to obtain the single-component high-strength epoxy structural adhesive.

[0081] Comparative Example 3

[0082] The single-component high-strength epoxy structural adhesive provided in this comparative example is prepared from the following components in parts by weight:

[0083] The preparation method is as follows: the bisphenol F diglycidyl ether, CTBN toughening agent, nano calcium carbonate, dicyandiamide curing agent, and substituted urea accelerator are mixed and stirred evenly, and the material is discharged to obtain the single-component high-strength epoxy structural adhesive.

[0084] Comparative Example 4

[0085] The single-component high-strength epoxy structural adhesive provided in this comparative example is prepared from the following components in parts by weight:

[0086] The toughening agent is the epoxy-modified hydrogenated silicone oil prepared in the aforementioned step a. The hydrogenated silicone oil containing hydrogen at both ends and having a hydrogen content of 0.2 mmol / g is used in the preparation process.

[0087] The preparation method is as follows: the bisphenol A diglycidyl ether epoxy resin, toughening agent, nano calcium carbonate, fumed silica, dicyandiamide curing agent, and substituted urea accelerator are mixed and stirred evenly, and the material is discharged to obtain the single-component high-strength epoxy structural adhesive.

[0088] Comparative Example 5

[0089] The single-component high-strength epoxy structural adhesive provided in this comparative example is prepared from the following components in parts by weight:

[0090] Wherein, the preparation method of the toughening agent is as follows:

[0091] A hydrogen-containing silicone oil with hydrogen at both ends and a hydrogen content of 0.2 mmol / g and the vinyl six-membered cyclic oligomeric silsesquioxane obtained in the above step b were added to the reactor in a molar ratio of 6:1, and an appropriate amount of Custer platinum catalyst was added. The mixture was stirred evenly and reacted at 60°C to obtain a toughening agent.

[0092] The preparation method of the one-component high-strength epoxy structural adhesive is as follows: the bisphenol A diglycidyl ether epoxy resin, toughening agent, nano calcium carbonate, fumed silica, dicyandiamide curing agent, and substituted urea accelerator are mixed and stirred evenly, and the material is discharged to obtain the one-component high-strength epoxy structural adhesive.

[0093] The following performance tests were performed on the epoxy structural adhesives prepared in Examples 1-5 and Comparative Examples 1-5:

[0094] The test substrate is cold rolled steel.

[0095] Shear strength: tested according to GB / T7124 method.

[0096] T-peel strength: tested according to GB / T2791 method.

[0097] -40℃ low temperature impact peel strength: tested according to GB / T36877 method, set temperature -40℃.

[0098] 80℃ impact peel strength: tested according to GB / T36877 method, set temperature 80℃.

[0099] Heat aging shear strength: Shear strength test specimens were prepared according to GB / T7124 and cured by baking at (170±2)°C for 20 minutes. The specimens were then removed and allowed to stand for 24 hours under standard conditions. The specimens were placed in a 130°C environmental chamber for 168 hours, then removed and allowed to stand at room temperature for 24 hours. The shear strength was then measured according to GB / T7124.

[0100] High-low temperature alternating shear strength: Prepare shear strength test specimens according to GB / T7124. After curing at (170±2)°C for 20 minutes, remove the specimens and allow them to stand under standard conditions for 24 hours. Perform four cycles under the following conditions. After removal, allow them to stand under standard conditions for 24 hours, and then measure the shear strength according to GB / T7124.

[0101] room temperature→high temperature→room temperature→low temperature

[0102] (23±2)℃×0.5h→(90±2)℃×4h→(23±2)℃×0.5h→(-40±2)℃×4h

[0103] The test results are shown in Table 1.

[0104] Table 1. Performance parameters of single-component high-strength epoxy structural adhesive

[0105] From the experimental results in Table 1, it can be seen that the single-component high-strength epoxy structural adhesives of Examples 1-5 prepared using the organic silicone resin toughening agent synthesized by the present invention all have relatively good shear strength and peel strength, and their 80°C impact peel strength, heat aging shear strength, and high and low temperature alternating shear strength are all better than those of Comparative Examples 1-5. Comparative Example 1 does not add any toughening agent, and its shear strength and peel strength are relatively low. This is mainly because the epoxy resin is relatively brittle and prone to brittle fracture, unable to withstand large stresses, and ultimately exhibits low mechanical properties. Comparative Examples 2 and Comparative Examples 3 use CTBN-terminated carboxyl liquid nitrile rubber for toughening and modification. Their mechanical properties are significantly improved relative to Comparative Example 1, but compared to the epoxy structural adhesive modified with the organic silicone resin toughening agent of the present invention, their 80°C impact peel strength and heat aging shear strength are relatively low. The mechanical properties of Examples 4-5 are lower than those of Examples 1-3, mainly because the epoxy resin content is reduced while too much toughening agent is added, resulting in insufficient rigidity and low strength of the prepared epoxy structural adhesive. Comparative Example 3 is compared with Example 4, and mechanical properties are lower, and particularly heat resistance is not as good as the organosilicon resin toughener of the present invention, mainly because the toughening effect and heat resistance of CTBN terminal carboxyl liquid acrylonitrile rubber are not as good as the organosilicon resin toughener of the present invention. Comparative Example 4 adopts the epoxy-modified hydrogenated silicone oil prepared in step a of the present invention as toughening agent, has certain toughening effect, but because the cohesive strength of the epoxy-modified hydrogenated silicone oil itself lacking annular network structure skeleton is not high, the mechanical properties of the epoxy structural adhesive finally prepared are also not large. The main difference between the toughening agent adopted by Comparative Example 5 and the organosilicon resin toughening agent adopted in Example 1 is that its end lacks a reactive epoxy group, and its compatibility with epoxy resin is relatively poor, and its enhanced toughening effect is far less than the organosilicon resin toughening agent containing six reactive epoxy groups of the present invention.

[0106] In summary, the organosilicon resin toughening agent synthesized by the present invention can effectively improve the strength, toughness and high and low temperature resistance of the one-component high-strength epoxy structural adhesive, and can better improve the durability of the epoxy structural adhesive. When used in automobile bodies, it can better ensure the structural safety of the automobile.

[0107] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0108] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A silicone resin toughening agent, characterized in that: Its structural formula is: Among them, 50≤n≤300.

2. The organosilicon resin toughening agent according to claim 1, characterized in that: 100≤n≤150。 3. A silicone resin toughening agent, characterized in that: The epoxy-modified hydrogen-containing silicone oil is prepared by reacting epoxy-modified hydrogen-containing silicone oil with vinyl six-membered cyclic oligomeric silsesquioxane; the epoxy-modified hydrogen-containing silicone oil is prepared by reacting allyl alcohol glycidyl ether with hydrogen-containing silicone oil at both ends; The structural formula of the vinyl hexacyclic oligomeric silsesquioxane is:

4. The organosilicon resin toughening agent according to claim 3, characterized in that: The molar ratio of allyl alcohol glycidyl ether, hydrogen-containing silicone oil and vinyl six-membered ring-polymerized silsesquioxane is 5-7:5-7:

1.

5. The organosilicon resin toughening agent according to claim 4, characterized in that: The molar ratio of allyl alcohol glycidyl ether, hydrogen-containing silicone oil and vinyl six-membered cyclic oligomeric silsesquioxane is 6:6:

1.

6. The organosilicon resin toughening agent according to claim 3, characterized in that: The hydrogen-containing silicone oil is a hydrogen-containing silicone oil containing hydrogen at both ends and having a hydrogen content of 0.09 mmol / g to 0.52 mmol / g.

7. The organosilicon resin toughening agent according to claim 6, characterized in that: The hydrogen-containing silicone oil is a hydrogen-containing silicone oil containing hydrogen at both ends and having a hydrogen content of 0.15 mmol / g to 0.25 mmol / g.

8. The organosilicon resin toughening agent according to any one of claims 2 to 7, characterized in that: The vinyl hexacyclic oligomeric silsesquioxane is obtained by reacting a hexavinylcyclohexasilanol potassium / copper salt complex with a mass ratio of 1:1-1.5 with trimethylchlorosilane; the hexavinylcyclohexasilanol potassium / copper salt complex is obtained by reacting vinyltrimethoxysilane with a base and then with cupric chloride dihydrate.

9. The organosilicon resin toughening agent according to claim 8, characterized in that: The alkali is sodium hydroxide and / or potassium hydroxide; and / or, The mass ratio of the vinyltrimethoxysilane, the alkali and the cupric chloride dihydrate is 1:0.4-0.5:0.3-0.

4.

10. The organosilicon resin toughening agent according to claim 8, characterized in that: The preparation method of the vinyl hexacyclic oligomeric silsesquioxane comprises the following steps: The first step: dissolving the vinyltrimethoxysilane in methanol, then adding alkali, stirring evenly, heating and reflux for 20 minutes to 30 minutes, adding a methanol solution containing copper chloride dihydrate, reflux for 20 minutes to 30 minutes, filtering out potassium chloride salt after cooling, and refrigerating the mixed solution at 5°C to 10°C to obtain hexavinylcyclohexasilane potassium / copper salt complex crystals; Step 2: adding potassium hexavinylcyclohexasilane / copper salt complex crystals and n-hexane solvent into a reaction container, dropping n-hexane solution containing trimethylsilyl chloride into the reaction container, stirring, reflux reaction for 8 hours to 16 hours, and post-treating to obtain the vinyl hexacyclic oligomeric silsesquioxane.

11. A method for preparing the organosilicon resin toughening agent according to any one of claims 1 to 10, characterized in that: The steps include: Add the hydrogen-containing silicone oil and an appropriate amount of Pt catalyst into a reactor, stir evenly, dropwise add the allyl alcohol glycidyl ether, and react at a temperature of 40° C. to 60° C. for 1 to 2 hours after the dropwise addition to obtain the epoxy-modified hydrogen-containing silicone oil; The epoxy-modified hydrogenated silicone oil and the vinyl six-membered cyclic oligomeric silsesquioxane are reacted at 50° C. to 70° C. under the action of a Pt catalyst for 1 to 2 hours to obtain the silicone resin toughening agent.

12. A one-component high-strength epoxy structural adhesive, characterized in that: The composition is prepared from the following raw materials in parts by weight: The organic silicone resin toughening agent is the organic silicone resin toughening agent according to any one of claims 1 to 10.

13. A one-component high-strength epoxy structural adhesive according to claim 12, characterized in that: The one-component high-strength epoxy structural adhesive is prepared from raw materials including the following components in parts by weight:

14. The one-component high-strength epoxy structural adhesive according to claim 13, characterized in that: The one-component high-strength epoxy structural adhesive is prepared from raw materials including the following components in parts by weight:

15. The one-component high-strength epoxy structural adhesive according to claim 12, characterized in that: The epoxy resin is selected from any one or more combinations of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, castor oil modified epoxy resin, polyurethane modified epoxy resin, silicone modified epoxy resin, and acrylate modified epoxy resin; and / or, The filler is selected from one or more combinations of nano calcium carbonate, heavy calcium carbonate, silicon powder, fumed silica, alumina, aluminum hydroxide, talc, and bentonite; and / or, The curing agent is dicyandiamide or hydrazide; and / or, The accelerator is selected from any one or more combinations of substituted urea, imidazole, and imidazole derivatives.

16. A method for preparing the one-component high-strength epoxy structural adhesive according to any one of claims 12 to 15, characterized in that: The method comprises the following steps: mixing the epoxy resin, the organosilicon resin toughening agent, the filler, the curing agent and the accelerator, and stirring them evenly to obtain the single-component high-strength epoxy structural adhesive.

Images