An end-capped polyurethane flexibilizer, an epoxy resin composition and a method for preparing the same

Abstract

The application relates to the field of epoxy resins, and more particularly to a capped polyurethane toughening agent, an epoxy resin composition and a preparation method thereof. The capped polyurethane toughening agent is prepared by reacting a hydroxyl-terminated polyester-imine polyol, a polyisocyanate, a chain extender and a blocking agent according to a feeding ratio of (66-83):(14-20):(0-2):(0.5-15). After the capped polyurethane toughening agent is applied to an epoxy resin system, the high-temperature resistance, toughness and strength of a chip packaging adhesive can be simultaneously solved, so that the corresponding epoxy resin system is applicable to the present stage of highly integrated circuit board packaging.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of epoxy resin, more particularly, it relates to an end-capped polyurethane toughening agent, an epoxy resin composition and a preparation method thereof. BACKGROUND

[0002] In the chip packaging application, the chip packaged by the epoxy glue has the functions of insulation, sealing, shock resistance and the like, and plays a protective role for the chip. However, with the development of high-frequency and high-speed integrated circuits towards integration and miniaturization, the traditional epoxy glue cannot be applied to the highly integrated chip packaging due to its poor temperature resistance, poor toughness, easy cracking and other defects.

[0003] On the highly integrated circuit board, a large amount of heat will be generated during the operation of the chip. With the long-term accumulation of heat, the chip packaging will crack and fail, that is, the packaging material will age, become brittle, warp and lose mechanical properties, and then the chip will be exposed and corroded. Therefore, chip packaging glue with temperature resistance has emerged in the market.

[0004] In the related art, the temperature resistance of the packaging glue is improved by using a multifunctional resin to increase the crosslinking density. However, it is known to those skilled in the art that the multifunctional resin will make the glue brittle and not tough. Insufficient toughness will also affect the packaging, and then cause the packaging to crack, the chip to be damaged or even to fail.

[0005] Therefore, some enterprises have replaced the multifunctional resin with an organic silicon modified resin at the present stage. However, the compatibility between the organic silicon and the epoxy resin is poor, and the interface separation or debonding problem easily occurs under extreme environment. The improvement of the toughness of the glue, especially the high-temperature toughness, is very limited, and the strength and modulus are greatly damaged.

[0006] If a conventional toughening technology is used, such as using a polyurethane, rubber, fatty acid or the like modified resin, the toughness can be effectively increased, but the heat resistance cannot be significantly improved or has a negative effect. For example, the method of using polytetramethylene ether glycol as a flexible chain and reacting with isocyanate monomer and then using a blocking agent for end-capping will reduce the high-temperature resistance of the epoxy resin material.

[0007] Therefore, how to solve the problem of the high-temperature toughness and strength of the chip packaging glue is a technical problem that needs to be solved by those skilled in the art. In summary, an end-capped polyurethane toughening agent, an epoxy resin composition and a preparation method thereof are provided, which can be applied to the packaging of the highly integrated circuit board at the present stage. SUMMARY

[0008] The application provides an end-capped polyurethane toughening agent, an epoxy resin composition and a preparation method thereof. The epoxy resin has excellent high strength and high-temperature toughness without damaging the modulus of the matrix, can ensure long-term reliability of packaging when used for chip packaging glue, enables the chip to work stably for a long time under different working environments and temperature conditions, and improves the service life of the chip.

[0009] In a first aspect, the application provides an end-capped polyurethane toughening agent, which is prepared by reacting a hydroxyl-terminated polyester-imine polyol, a polyisocyanate, a chain extender and a blocking agent in a feeding ratio of (66-83):(14-20):(0-2):(0.5-15).

[0010] The hydroxyl-terminated polyester-imine polyol has the following structural formula: Formula (I);

[0011] The R has the following structural formula: .

[0012] Preferably, the end-capped polyurethane toughening agent is prepared by the following preparation process:

[0013] 1) In a reaction kettle, the hydroxyl-terminated polyester-imine polyol is dehydrated at 95-110°C under vacuum to a negative pressure of 0.09-0.1 MPa for 1-2 hours with minimum stirring;

[0014] 2) After cooling to 25-50°C, the polyisocyanate and the catalyst are added, and the reaction is carried out at 50-80°C with stirring under a nitrogen atmosphere for 2-4 hours to obtain an isocyanate-terminated polymer;

[0015] 3) When the NCO content of the polymer is 1.20-6.00%, the chain extender is added to the isocyanate-terminated polymer obtained in 2) under a nitrogen atmosphere, and the reaction is carried out at 50-80°C with stirring for 1-2 hours;

[0016] 4) When the NCO content of the polymer is 1.20-4.50%, the blocking agent and the catalyst are continuously added, and the reaction is carried out at 80-110°C with vigorous stirring for 2-12 hours, and the blocking agent is added and the reaction is continuously carried out for 1-4 hours to obtain the end-capped polyurethane toughening agent. To complete the blocking of the isocyanate, the final product is placed in an oven at 70°C overnight, and the NCO content is 0-0.10%.

[0017] Preferably, the hydroxyl-terminated polyester-imine polyol has a hydroxyl value of 20-120 mg / KOH.

[0018] Preferably, the chain extender is selected from one or more of 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, ethylene glycol, diethylene glycol, 1,3-propanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol / neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 1,8-octanediol, 2,4-diethyl-1,3-octanediol, trimethyl-1,6-hexanediol, 1,7-heptanediol, 4-propyl-1,8-octanediol, 1,9-nonanediol, hydroquinone dihydroxyethyl ether, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,4-diethyl-1,5-pentanediol, polypropylene oxide polyols having a molecular weight of 200-1000, trimethylolpropane, glycerol.

[0019] Preferably, the blocking agent is selected from one or more of phenol, cresol, dimethylphenol, p-tert-butylphenol, 3-pentadecenylphenol, pyridinol, 2-trifluoroethanol, triphenylthiol, hexanethiol, dodecyl mercaptan, acetanilide, caprolactam, 2-butanone oxime, 2,2'-diallyl bisphenol A, 4-vinylphenol, p-aminophenol, cardanol, p-acetylamino phenol, p-acetylphenol.

[0020] Preferably, the catalyst is selected from dibutyltin dilaurate (DBTL) or bismuth-III neodecanoate.

[0021] In a second aspect, the present application provides a high-strength, high-temperature-resistant toughened epoxy resin, comprising an epoxy resin and any of the above-mentioned capped polyurethane toughening agents.

[0022] Preferably, the high-strength, high-temperature-resistant toughened epoxy resin is composed of the following components by weight:

[0023] 5-60 parts of any of the above-mentioned capped polyurethane toughening agents;

[0024] 50-100 parts of an epoxy resin;

[0025] 5-20 parts of a curing agent;

[0026] 0.01-5.0 parts of an accelerator;

[0027] 0-10 parts of a functional auxiliary agent.

[0028] Preferably, the epoxy resin is one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated epoxy resin, glycidyl amine type epoxy resin, glycidyl ester type epoxy resin, silicone-modified epoxy resin, phosphoric acid-modified epoxy resin, polyurethane-modified epoxy resin, fatty acid-modified epoxy resin, rubber-modified epoxy resin.

[0029] Preferably, the curing agent is one or more of fatty amines, alicyclic amines, dicyanamide, polyamide, imidazole, epoxy resin modified modified amine, polyether amine, hydrazide, diaminodiphenyl sulfone, boron trifluoride amine complex, organic urea, acid anhydride and mercaptan.

[0030] Preferably, the accelerator is one or more of fatty amine accelerator, acid anhydride accelerator, polyether amine accelerator, urea accelerator, imidazole accelerator mixed in any ratio.

[0031] Preferably, the functional aid is one or more of fillers, stabilizers, diluents, defoamers, thixotropic agents, coupling agents, dispersants, etc.

[0032] In a third aspect, the application discloses a preparation method of high-strength and high-temperature-resistant toughened epoxy resin, comprising the following steps:

[0033] S1, first heat the epoxy resin and the capped polyurethane toughening agent to 60-80℃ and mix uniformly, cool to 30-40℃, then add the curing agent, accelerator and functional aid in turn, mix uniformly, then perform vacuum degassing after ultrasonic vibration treatment to obtain a prepolymer;

[0034] S2, pour the prepolymer obtained in S1 into a mold, raise the temperature to 100-120℃ and cure for 1-4h, continue to raise the temperature to 130-150℃ and cure for 2-5h, after curing, cool to room temperature with the furnace, demold, and high-strength and high-temperature-resistant toughened epoxy resin is obtained.

[0035] In summary, the application has the following beneficial effects:

[0036] 1. The capped polyurethane toughening agent in the application is synthesized by using a hydroxyl-terminated polyester imine polyol as a main raw material, and the chain length and intermolecular force of the capped polyurethane are regulated by the structure-activity relationship and the proportion relationship between the isocyanate group and the polyester imine polyol, so that a suitable phase separation structure is obtained, and then excellent high-temperature resistance and flexibility are obtained, which meets the application premise of the epoxy resin system;

[0037] 2. The capped polyurethane toughening agent obtained in the application can significantly realize high-temperature toughening effect when applied in the epoxy resin system, compared with other toughening agents, the toughening agent can improve the high-temperature resistance and strength of the epoxy resin under the premise of ensuring the modulus of the resin matrix, so that it meets the application conditions in the chip packaging glue;

[0038] 3、The preparation method of the high-strength and high-temperature-resistant toughened epoxy resin in the application is relatively simple, each operation and condition is easy to achieve, and stable and uniform products can be obtained, which is conducive to industrialized production. The obtained product can also be regulated by process method, and the mixing and curing process is controlled to achieve further toughening effect. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The infrared spectrum of the hydroxyl-terminated polyester-imine polyol obtained in Preparation Example 1 is shown in the following figure:

[0040] Figure 2 The infrared spectrum of the capped polyurethane toughening agent obtained in Preparation Example 2 is shown in the following figure. DETAILED DESCRIPTION

[0041] The application will be further described in detail below in combination with the accompanying Figures 1-2 , Preparation Examples and Examples.

[0042] The raw materials and / or equipment used in each of the preparation examples, examples and tests of the application are conventional raw materials and equipment available on the market, except for the special description in Table 1 below:

[0043] Table 1: List of raw materials and equipment

[0044]

[0045] Preparation Example 1

[0046] A hydroxyl-terminated polyester-imine polyol has the following structural formula: Formula (I);

[0047] The structural formula of R is: , and is prepared by the following preparation steps:

[0048] The polyol monomer, polybasic acid monomer, catalyst, TMA and MDA are added in a reaction kettle at room temperature, and the temperature is raised to 220℃ during the feeding process, and the column top temperature is controlled at 102℃ during the process;

[0049] The polyol monomer is polyoxypropylene glycol 400; the polybasic acid monomer is adipic acid; and the catalyst is butyl orthotitanate;

[0050] The feeding ratio of the polyol monomer, polybasic acid monomer, catalyst, TMA and MDA is 60.71:8.08:0.08:20.54:10.59;

[0051] Then vacuumize, and gradually increase the vacuum degree, distill the reaction by-products under reduced pressure, and keep warm for 2h to obtain the hydroxyl-terminated polyester-imine polyol.

[0052] The infrared spectrum thereof is as shown in the following figure:Figure 1 As shown in the figure, the characteristic absorption peaks of the hydroxyl-terminated polyester-imine polyol are found: 3471.34 cm -1 corresponding to the stretching vibration absorption peak of hydroxyl, 2970.04 cm -1 and 2868.05 cm -1 corresponding to the stretching vibration absorption peak of methyl, 1780.96 cm -1 and 1717.04 cm -1 corresponding to the asymmetric and symmetric stretching vibration peaks of imine ring structure -CO-N-CO-, respectively, 1692.37 cm -1 corresponding to the stretching vibration absorption peak of imide C=O, 1514.17 cm -1 corresponding to the stretching vibration absorption peak of benzene ring skeleton, 1365.02 cm -1 corresponding to the axial vibration peak of imide ring, 1216.00 cm -1 corresponding to the C-N stretching vibration absorption peak, 1093.45 cm -1 corresponding to the C-O-C stretching vibration absorption peak on the polyoxypropylene diol, 723.71 cm -1 corresponding to the C=O bending vibration absorption peak of imide.

[0053] The appearance of the above characteristic absorption peaks indicates the presence of imine ring structure in the structure, and it is determined that the hydroxyl-terminated polyester-imine polyol can be synthesized by the above process. The hydroxyl value of the above polyester-imine polyol is 56.8 mgKOH / g, [OH] / [COOH] is equal to 1.39, and the content of TMA and MDA is equal to 31.13%.

[0054] Preparation Example 2

[0055] A capped polyurethane toughener is prepared by the following preparation process:

[0056] 1) In a reaction kettle, 74.38 g of the hydroxyl-terminated polyester-imine polyol in Preparation Example 1 is dehydrated at 100°C under vacuum (negative pressure 0.1 MPa) with minimum stirring for 1 hour;

[0057] 2) After cooling to 40°C, 16.77 g of IPDI and 0.015 g of catalyst are added, and the reaction is carried out at 70°C under nitrogen atmosphere with stirring for 2 hours to obtain an isocyanate-terminated polymer;

[0058] 3) When the NCO content in the polymer is 3.47%, 1.36 g of chain extender is added to the isocyanate-terminated polymer obtained in 2) under nitrogen atmosphere, and the reaction is carried out at 70°C with moderate stirring for 1 hour;

[0059] 4) When the NCO content of the polymer is 2.05%, continue to add 6.80 g of blocking agent and 0.015 g of catalyst, react at 90°C with vigorous stirring for 3 hours, add 0.66 g of blocking agent, continue to react for 2 hours, obtain a blocked polymer, to complete the blocking of isocyanate, place the polymer in an oven at 70°C overnight, the final product has an NCO content of less than 0.1%;

[0060] The hydroxyl-terminated polyester-imine polyol in the above preparation step is prepared according to Preparation Example 1, the catalyst is DBTL, the chain extender is 1,4-butanediol, the blocking agent is p-t-butylphenol, and the hydroxyl-terminated polyester-imine polyol, the polyisocyanate, the chain extender, the blocking agent, and the catalyst are added in a ratio of 74.38:16.77:1.36:7.46:0.03.

[0061] The infrared spectrum thereof is shown in FIG. 1. Figure 2 From the figure, characteristic absorption peaks of the blocked polyurethane toughener are found: 3334.15 cm -1 nearby appear the stretching vibration absorption peaks of the amino group, 1675.00 cm -1 and 1631.00 cm -1 are the stretching vibration absorption peaks of the carboxyl group in the newly formed urethane (-NHCOO-), and 1252.44 cm -1 is the asymmetric stretching vibration absorption peak of the newly formed aryl ether bond (C-O-C). The appearance of the above characteristic absorption peaks indicates the presence of the urethane group in the structure, and it is determined that the blocked polyurethane toughener can be synthesized through the above process.

[0062] Preparation Examples 3-6

[0063] A blocked polyurethane toughener, which differs from Preparation Example 2 in that the ratios of the materials are different, as shown in Table 2:

[0064] Table 2: Comparison table of the ratios of the materials in Preparation Examples 3-6

[0065]

[0066] Preparation Examples 7-11

[0067] A blocked polyurethane toughener, which differs from Preparation Example 2 in that the specific selection of the materials is different, as shown in Table 3:

[0068] Table 3: Comparison table of the selection of the materials in Preparation Examples 7-11

[0069]

[0070] From the analysis of Table 2 and Table 3, it can be seen that by adjusting the types of chain extender, end-capping agent and catalyst, end-capped polyurethane toughening agents with different structures and different properties can be obtained. Those skilled in the art can select different chain extenders, end-capping agents and catalysts according to different application scenarios.

[0071] Performance detection test

[0072] The epoxy resin compositions prepared in the examples and comparative examples were taken as detection objects, and then the tensile strength, elongation at break and impact toughness of the epoxy resin cured products before and after high temperature treatment at 200℃ were tested. The specific detection steps and conditions are as follows:

[0073] Tensile strength and elongation at break test method: sample preparation was carried out according to the method described in GB / T 2567-2008, tensile test was carried out at room temperature 23±2℃, and the load applied on the sample and the elongation of the sample were measured respectively, and then the tensile strength and elongation at break of the sample were calculated.

[0074] Impact toughness test method: sample preparation was carried out according to the method described in GB / T 2567-2008, and a simply supported beam impact tester was used to carry out impact test at room temperature 23±2℃, and the impact strength of the sample was measured respectively to characterize the toughness and strength of the composition. The above tests were carried out for 3 parallel tests for each group, and the average value was taken as the final measured value.

[0075] Examples 1-5

[0076] A high-strength, high-temperature-resistant toughened epoxy resin, the weight (g) of each component of which is shown in Table 4, and is prepared by the following preparation process:

[0077] S1, first mix and heat the epoxy resin and the end-capped polyurethane toughening agent to 80℃, cool it to 40℃, then add the curing agent, the accelerator and the functional additive in turn, mix uniformly, then treat by ultrasonic vibration, and then vacuum degassing to obtain a prepolymer;

[0078] The epoxy resin is epoxy resin BE188EL, the end-capped polyurethane toughening agent is prepared by Preparation Example 2, the curing agent is ultra-fine dicyandiamide curing agent 100S (Germany Wincell), the accelerator is UR500 (CVC Corpation), and the functional additive is fumed silica;

[0079] S2, pour the prepolymer obtained in S1 into a mold, raise the temperature to 120℃ and cure for 2h, continue to raise the temperature to 150℃ and cure for 3h, and then cool to room temperature with the furnace after curing is completed, demold, and then a high-strength, high-temperature-resistant toughened epoxy resin is obtained.

[0080] Table 4: Components and their weights (g) of high-strength, high-temperature-resistant toughened epoxy resin in Examples 1-5

[0081]

[0082] Comparative Example 1

[0083] A toughened epoxy resin, which is different from Example 1 in that the components and amounts are shown in Table 5, and the end-capped polyurethane toughening agent is prepared by reacting polytetramethylene ether glycol as a flexible chain with isocyanate monomers and then end-capping with a blocking agent, corresponding to the background technology.

[0084] Table 5: Components of the toughened epoxy resin in Comparative Example 1 and their weights (g)

[0085]

[0086] The epoxy resin compositions in the above Examples 1-5 and Comparative Example 1 were extracted, and their tensile strength, elongation at break and impact toughness before and after high temperature treatment at 200°C were tested, with 3 parallel tests for each group, and the test results were averaged and recorded in Table 6.

[0087] Table 6: Performance comparison table in Examples 1-5 and Comparative Example 1

[0088]

[0089] As can be seen from Table 6, the epoxy resin compositions obtained in Examples 1-5 all have excellent high temperature toughness, which can meet the application in chip packaging, and their tensile strength before high temperature aging is 80.0-85.6 MPa, elongation at break is 5.6%-12.3%, and impact toughness is 30.8-44.1 KJ / m 2 ;

[0090] The tensile strength after high temperature aging is 64.8-77.0 MPa, which is only decreased by 9.51%-19.00% compared with before high temperature aging, the elongation at break is 4.0%-8.9%, which is decreased by 12.74%-30.89% compared with before high temperature aging, and the impact toughness is 21.7-33.3 KJ / m 2 , which is only decreased by 18.18%-31.29% compared with before high temperature aging;

[0091] Within a certain range, as the amount of end-capped polyurethane toughening agent increases, the tensile strength, elongation at break, toughness and high temperature resistance of the high-strength, high-temperature-resistant toughened epoxy resin also increase, but when the amount of end-capped polyurethane toughening agent exceeds 36%, the tensile strength, elongation at break and toughness have a decreasing trend;

[0092] Therefore, the preferred weight fractions of the components in the high-strength, high-temperature-resistant toughened epoxy resin are:

[0093] Any of the above capped polyurethane toughening agent 5-60 parts, epoxy resin 50-100 parts, curing agent 5-20 parts, accelerator 0.01-5.0 parts, the range can obtain stable performance uniform product.

[0094] From the data of Comparative Example 1 and the blank group, it can be seen that the tensile strength after high temperature aging is decreased by 32.82% and 20.86% respectively, the elongation at break is decreased by 55.92% and 33.33% respectively, and the impact toughness is decreased by 67.28% and 39.91% respectively compared with before high temperature aging. It can be seen that the attenuation of tensile strength, elongation at break and impact toughness in Examples 1-5 is far less than that of Comparative Example 1 and the blank group. Combined with the above data, the theoretical basis and reasons are as follows:

[0095] The epoxy resin system toughened by the capped polyurethane toughening agent in the present application benefits from the structure-activity relationship and the proportion relationship between isocyanate group and polyester imine polyol, which significantly improves the chain length of the capped polyurethane. Therefore, when applied to the epoxy resin system, it can impart excellent high strength and high temperature toughness to the epoxy resin matrix without compromising the modulus of the epoxy resin matrix, thereby meeting the application conditions.

[0096] Examples 6-9

[0097] A high-strength, high-temperature-resistant toughened epoxy resin, which differs from Example 1 in the use of capped polyurethane toughening agent, as shown in Table 7 below:

[0098] Table 7: Comparison table of capped polyurethane toughening agent use in Examples 6-9

[0099]

[0100] The epoxy resin compositions in Examples 6-9 above were extracted and tested for tensile strength, elongation at break and impact toughness before and after 200℃ high temperature treatment. Each group was tested in triplicate, and the average value was recorded in Table 8.

[0101] Table 8: Performance comparison table of Examples 6-9

[0102]

[0103] As can be seen from Table 8, the epoxy resin compositions obtained in Examples 6-9 all have excellent high temperature toughness, which can meet the application in chip packaging. The tensile strength before high temperature aging is 79.5-84.6 MPa, the elongation at break is 8.0-10.6%, and the impact toughness is 33.8-39.8 KJ / m 2 ;

[0104] The tensile strength after high temperature aging is 66.8-74.4 MPa, which only decreases by 9.16%-15.97% compared with before high temperature aging, the elongation at break is 6.4%-8.0%, which decreases by 19.78%-24.53% compared with before high temperature aging, and the impact toughness is 25.2-29.7 KJ / m 2 , which only decreases by 21.93%-26.57% compared with before high temperature aging;

[0105] It can be seen from the above Table 8 that by adjusting the amount of hydroxyl-terminated polyester-imine polyol, polyisocyanate, chain extender and blocking agent, a blocked polyurethane toughening agent with different molecular weight and distribution can be obtained. In order to obtain a blocked polyurethane toughening agent, the proportion of hydroxyl-terminated polyester-imine polyol and polyisocyanate is preferably such that the [NCO] groups are present in stoichiometric excess compared to [OH], i.e. the molar ratio of [NCO] to [OH] is greater than 1. The use of chain extender can control the hard segment structure and microphase separation degree of polyurethane, and the proportion of chain extender in the present application is in the range of 0-4. The preferred proportion of blocking agent is such that the active hydrogen groups [H] in the blocking agent are present in excess relative to the residual [NCO], i.e. the molar ratio of active hydrogen [H] to residual [NCO] is greater than 1, and the proportion of blocking agent in the present application is in the range of 0-30.

[0106] It can be seen that by appropriately increasing the amount of hydroxyl-terminated polyester-imine polyol, polyisocyanate, chain extender and blocking agent, the tensile strength, elongation at break, toughness and heat resistance of the obtained toughened epoxy resin are improved, but too much amount is not conducive.

[0107] Examples 10-14

[0108] A high-strength, high-temperature-resistant toughened epoxy resin, which differs from Example 1 in the use of blocked polyurethane toughening agent, as shown in Table 9:

[0109] Table 9: Comparison table of use of blocked polyurethane toughening agent in Examples 10-14

[0110]

[0111] The epoxy resin compositions in the above Examples 10-14 were extracted, and the tensile strength, elongation at break and impact toughness before and after 200℃ high temperature treatment were tested, 3 parallel tests were performed for each group, and the test results were averaged and recorded in Table 10.

[0112] Table 10: Performance comparison table of Examples 10-14

[0113]

[0114] As can be seen from Table 10, the epoxy resin compositions obtained in Examples 10-14 all have excellent high-temperature toughness, and can meet the application requirements in chip packaging, with the tensile strength before high-temperature aging of 78.8-91.6 MPa, the elongation at break of 6.6%-11.6%, and the impact toughness of 30.1-44.7 KJ / m 2 .

[0115] The tensile strength after high-temperature aging is 62.8-85.3 MPa, which is only decreased by 5.64%-20.30% compared with that before high-temperature aging, the elongation at break is 5.0%-9.6%, which is decreased by 7.35%-26.72% compared with that before high-temperature aging, and the impact toughness is 22.5-36.4 KJ / m 2 , which is only decreased by 9.00%-27.07% compared with that before high-temperature aging.

[0116] It can be seen that the chain extender with longer molecular chain can improve the elongation at break and toughness of the toughened epoxy resin composition, the chain extender containing benzene ring structure, i.e. hydroxyethyl ether of hydroquinone, can improve the tensile strength and heat resistance of the toughened epoxy resin composition; the strength, elongation at break and toughness of the toughened epoxy resin composition after high-temperature aging are all decreased to a smaller extent when the end-capping agent is different from that in Comparative Example 1, but the strength, elongation at break and toughness of the cured product are greatly affected by the deblocking temperature when the end-capping agent is different; the catalyst used in the synthesis of the end-capped polyurethane toughening agent also has a certain influence on the properties of the toughened epoxy resin composition, DBTL is more beneficial to the tensile strength, while bismuth neodecanoate is more beneficial to the elongation at break, toughness and heat resistance.

[0117] It should be particularly pointed out that the curing agent and curing accelerator in the present application can be routinely replaced by those skilled in the art according to actual needs, considering that the addition effect can be expected by those skilled in the art on the premise that the reaction principle does not change, and the present application is better for controlling a single variable, so no one-by-one test is performed, and it should not be regarded as a limitation on the protection scope of the present application.

[0118] The present specific preparation example is only an explanation of the present application, and is not a limitation on the present application, and those skilled in the art can make modifications to the present preparation example without creative contribution according to needs after reading the present specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A high temperature resistant end-capped polyurethane flexibilizer, characterized in that, The hydroxyl-terminated polyester-imine polyol is prepared by reacting a hydroxyl-terminated polyester-imine polyol, a polyisocyanate, a chain extender, and a blocking agent in a feeding ratio of (66-83):(14-20):(0-2):(0.5-15); The hydroxyl-terminated polyester-imine polyol has the following structural formula: Formula (I); The structural formula of R is ; The hydroxyl-terminated polyester-imine polyol is prepared by the following preparation steps: The polyol monomer, the polyacid monomer, the catalyst, TMA, and MDA are added into a reaction kettle at room temperature, and the temperature is increased to 220°C during the feeding process, and the column top temperature is controlled at 102°C during the process; The polyol monomer is polyoxypropylene glycol 400; The polyacid monomer is adipic acid; The catalyst is butyl orthotitanate; The feeding ratio of the polyol monomer, the polyacid monomer, the catalyst, TMA, and MDA is 60.71:8.08:0.08:20.54:10.59; Then, vacuum is drawn, and the vacuum degree is gradually increased, the reaction by-products are distilled out under reduced pressure, and the hydroxyl-terminated polyester-imine polyol is obtained after 2h of heat preservation; The capped high-temperature-resistant polyurethane toughening agent is prepared by the following preparation process: 1) In a reaction kettle, the hydroxyl-terminated polyester-imine polyol is dehydrated at 95-110°C under vacuum to a negative pressure of 0.09-0.1 MPa for 1-2 hours with minimum stirring; 2) After cooling to 25-50°C, the polyisocyanate and the catalyst are added, and the reaction is carried out at 50-80°C under a nitrogen atmosphere with stirring for 2-4 hours to obtain an isocyanate-terminated polymer; 3) When the NCO content in the polymer is 1.20-6.00%, the chain extender is added to the isocyanate-terminated polymer obtained in 2) under a nitrogen atmosphere, and the reaction is carried out at 50-80°C with stirring for 1-2 hours; 4) When the NCO content in the polymer is 1.20-4.50%, the blocking agent and the catalyst are continuously added, and the reaction is carried out at 80-110°C with vigorous stirring for 2-12 hours, the blocking agent is additionally added, and the reaction is continuously carried out for 1-4h to obtain the capped high-temperature-resistant polyurethane toughening agent, and the NCO content of the final product is 0-0.10% after being placed in a 70°C oven overnight to complete the blocking of the isocyanate.

2. The end-capped high temperature resistant polyurethane flexibilizer according to claim 1, wherein, The hydroxyl-terminated polyester-imine polyol has a hydroxyl value of 28-224 mg / KOH.

3. The end-capped high temperature resistant polyurethane flexibilizer according to claim 1, wherein, The chain extender is selected from one or more of 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, ethylene glycol, diethylene glycol, 1,3-propanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 1,8-octanediol, 2,4-diethyl-1,3-octanediol, trimethyl-1,6-hexanediol, 1,7-heptanediol, 4-propyl-1,8-octanediol, 1,9-nonanediol, hydroquinone dihydroxyethyl ether, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,4-diethyl-1,5-pentanediol, polyoxypropylene polyols with a molecular weight of 200-1000, trimethylolpropane, glycerol.

4. The end-capped high temperature resistant polyurethane flexibilizer according to claim 1, wherein, The blocking agent is selected from one or more of phenol, cresol, dimethylphenol, p-tert-butylphenol, 3-pentadecenylphenol, pyridinol, 2-trifluoroethanol, thiophenol, hexanethiol, dodecyl mercaptan, acetanilide, caprolactam, dibutyl ketoxime, 2,2'-diallyl bisphenol A, 4-vinylphenol, p-aminophenol, cardanol, p-acetylamino phenol, p-acetylphenol.

5. The end-capped high temperature resistant polyurethane flexibilizer according to claim 1, wherein, The catalyst is selected from dibutyltin dilaurate-DBTL or bismuth neodecanoate-III.

6. A high-strength, high-temperature resistant, toughened epoxy resin composition, characterized by, The epoxy resin and the capped high-temperature-resistant polyurethane toughening agent of any one of claims 1-5 are included.

7. A high-strength, high-temperature resistant, toughened epoxy resin composition, characterized by, The components are included in the following weight parts: 5-60 parts of the capped high-temperature-resistant polyurethane toughening agent of any one of claims 1-5; 50-100 parts of the epoxy resin; 5-20 parts of the curing agent; 0.01-5.0 parts of the accelerator.

8. The high-strength, high-temperature-resistant, toughened epoxy resin composition according to claim 7, characterized in that, 0-10 parts of a functional aid, which is one or more of a filler, a stabilizer, a diluent, an antifoaming agent, a thixotropic agent, a coupling agent, a dispersant, and is not zero.

9. The method of making a high-strength, high-temperature resistant, toughened epoxy resin composition according to any one of claims 7-8, characterized in that, The following steps are included: S1, first mix the epoxy resin and the capped high-temperature-resistant polyurethane toughening agent and heat to 60-80 ℃, then cool to 30-40 ℃, then sequentially add the curing agent, the accelerator, and the optional functional aid, mix uniformly, then perform ultrasonic vibration treatment, and then perform vacuum degassing to obtain a prepolymer; S2, cast the prepolymer obtained in S1 in a mold, raise the temperature to 100-120 ℃, cure for 1-4 h, continue to raise the temperature to 130-150 ℃, cure for 2-5 h, after curing is completed, cool to room temperature with the furnace, demold, and the high-strength, high-temperature-resistant toughened epoxy resin is obtained.

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