Flame-retardant high-Tg fast-curing epoxy resin for PCM and preparation method thereof

Abstract

The invention relates to the field of epoxy resin, in particular to flame-retardant high-Tg fast-curing epoxy resin for PCM (pulse code modulation) and a preparation method of the flame-retardant high-Tg fast-curing epoxy resin. The raw materials comprise the following components in parts by weight: 100 parts of multifunctional epoxy resin; the polyfunctional epoxy resin is a mixture of p-aminophenol epoxy resin and 4, 4-diaminodiphenylmethane epoxy resin, the glass transition temperature of the polyfunctional epoxy resin is 240-250 DEG C, and the epoxy equivalent is 100-125; 5 to 10 parts of a PES toughening agent; 15 to 20 parts of a flame retardant; 0.3 to 0.5 part of fumed silica; 5.5 to 7 parts of a dicyandiamide curing agent; and 1.5-3 parts of a urea accelerator. The epoxy resin prepared by the preparation method disclosed by the invention not only has relatively high glass transition temperature, but also has good mechanical properties, toughness and flame retardance and is short in curing time; meanwhile, the preparation raw materials are easy to obtain, and the process is simple.

Description

Technical Field

[0001] This application relates to the field of epoxy resins. More specifically, it relates to an epoxy resin for rapidly curing PCM with flame retardancy and high Tg and its preparation method. Background Art

[0002] The PCM molding process is a molding process for composite semi-finished products in which resin is pre-impregnated in fiber-reinforced materials. It can significantly shorten the molding cycle, improve production efficiency, and easily achieve one-time molding of complex structural parts. Moreover, the fiber orientation in the product is good, so the strength and stiffness of the product are relatively high. It is widely used in fields such as sports goods, aircraft, and automobiles. With the development of industry, the performance requirements for roof crossbeams are getting higher and higher, including flame retardancy, glass transition temperature, mechanical properties, etc. However, although the current mainstream method of adding phosphorus-based / nitrogen-based flame retardants can reach UL94 V-0 level, it affects the glass transition temperature. Introducing multi-functional epoxy / rigid structures into the resin system can increase the glass transition temperature, but it will lead to an increase in viscosity and poor wettability to fiber-reinforced materials.

[0003] The Chinese patent with the patent number CN115433095B discloses a cyclohexylamine derivative and its preparation method, an epoxy resin composition and its preparation method and application. First, a cyclohexylamine derivative containing primary, secondary, and tertiary amine structures is synthesized by reacting acrylonitrile with cyclohexylamine, and then it is used in combination with a latent curing agent to provide an epoxy resin composition, the composition of which includes component A epoxy resin and component B epoxy curing agent; component A contains at least one epoxy resin; component B contains the above cyclohexylamine derivative, latent amine curing agent, alicyclic amine, polyether amine, and basic curing accelerator; its glass transition temperature is between 76-79°C, and the glass transition temperature is too low.

[0004] The Chinese patent with the patent number CN110128785B discloses a high-temperature resistant and high-toughness epoxy resin for composite prepregs. The preparation process is as follows: (1) Preheat triphenylmethane triglycidyl ether and triglycidyl p-aminophenol to good fluidity; (2) Mix the preheated triphenylmethane triglycidyl ether and triglycidyl p-aminophenol in step (1) according to the weight ratio and heat to 70-130°C; (3) Add o-cresol novolac epoxy resin to step (2), continue to heat up to 90-160°C, keep warm for 30-60 minutes and then let it stand and cool to 40-90°C; (4) Add a curing agent and a toughening agent to step (3), and mix and heat all the above materials under the state of high-speed stirring and dispersion to obtain a high-temperature resistant and high-toughness epoxy resin. The viscosity at 50-75°C is 16000-20000 mPa·S, and the glass transition temperature measured by TgDMA is greater than 330°C. However, this patent needs to be cured at 180-250°C for 4-16 hours, and the curing time is too long. Summary of the Invention

[0005] The present application provides an epoxy resin for a flame-retardant, high-Tg, and rapidly curable PCM and a preparation method thereof. The epoxy resin prepared in the present application not only has a relatively high glass transition temperature but also has good mechanical properties, toughness, and flame retardancy, and a short curing time. At the same time, the raw materials for the preparation in the present application are easily available and the process is simple.

[0006] In a first aspect, the present application provides an epoxy resin for a flame-retardant, high-Tg, and rapidly curable PCM, adopting the following technical solution:

[0007] An epoxy resin for a flame-retardant, high-Tg, and rapidly curable PCM, the raw materials include the following components by weight:

[0008] 100 parts of a polyfunctional epoxy resin; the polyfunctional epoxy resin is a mixture of a p-aminophenol type epoxy resin and a 4,4-diaminodiphenylmethane type epoxy resin, the glass transition temperature of the polyfunctional epoxy resin is 240 - 250 °C, and the epoxy equivalent is 100 - 125;

[0009] 5 - 10 parts of a PES toughening agent; the particle size of the PES toughening agent is 5 - 10 μm;

[0010] 15 - 20 parts of a flame retardant;

[0011] 0.3 - 0.5 part of fumed silica; the specific surface area of the fumed silica is 90 - 100 m 2 / g;

[0012] 5.5 - 7 parts of a dicyandiamide curing agent;

[0013] 1.5 - 3 parts of a urea-based accelerator.

[0014] Further, the weight ratio of the p-aminophenol type epoxy resin to the 4,4-diaminodiphenylmethane type epoxy resin is (1 - 1.1):1.

[0015] Further, the relative density of the PES toughening agent is 1.3 - 1.5 g / cm 3 .

[0016] Further, the urea-based accelerator is an organic urea.

[0017] Further, the flame retardant is a mixture of a tetrabromobisphenol A type epoxy resin and antimony trioxide, and the weight ratio of the tetrabromobisphenol A type epoxy resin to antimony trioxide is (15 - 17):3.

[0018] In a second aspect, the present application provides an epoxy resin for a flame-retardant, high-Tg, and rapidly curable PCM and a preparation method thereof, adopting the following technical solution:

[0019] A preparation method of an epoxy resin for a flame-retardant, high-Tg and fast-curing PCM, comprising the following steps:

[0020] Heat the polyfunctional epoxy resin and the PES toughening agent to 170 ± 5 °C, with a rotation speed of 100 - 200 rad / min, and keep warm for 2.5 - 3.5 h;

[0021] Then lower the temperature to 100 ± 5 °C, adjust the rotation speed to 300 - 400 rad / min, add fumed silica and a flame retardant, and stir for 60 - 65 min;

[0022] Lower the temperature to 80 ± 5 °C, add a dicyandiamide curing agent, with a rotation speed of 300 - 500 r / min, and stir for 8 - 10 min;

[0023] After the stirring is completed, lower the temperature to 60 ± 5 °C, add a urea accelerator, with a rotation speed of 300 - 500 r / min, and stir for 5 - 8 min to obtain the epoxy resin.

[0024] Further, preheat the polyfunctional epoxy resin at 80 ± 5 °C for a preheating time of more than 2 h, and then heat it to 170 ± 5 °C.

[0025] Further, during the addition of the dicyandiamide curing agent, adjust the rotation speed to 25 ± 5 r / min.

[0026] Further, during the addition of the urea accelerator, adjust the rotation speed to 25 ± 5 r / min.

[0027] In summary, the present application has the following beneficial effects:

[0028] 1. The epoxy resin for PCM prepared in the present application has a Tg > 160 °C (DSC), a curing time of 5 min (150 °C), and a flame retardant grade of UL94 V-0. Compared with the traditional system, the Tg of the present application is increased, the curing time is shortened, the synergy of flame retardancy and high Tg / fast curing is achieved, and the performance is excellent, meeting the performance requirements of the PCM roof cross beam.

[0029] 2. The present application preferably uses a multi-functional epoxy resin with a high Tg, which can improve the glass transition temperature of the epoxy resin. However, the use of a multi-functional epoxy resin with a high Tg has a high viscosity on the one hand, and on the other hand, it will cause the mechanical properties of the product to deteriorate. Therefore, the present application adds a PES toughening agent. The specific PES toughening agent and the specific multi-functional epoxy resin are used in combination to improve the mechanical properties of the product while reducing the influence of the addition of the toughening agent on the resin viscosity and wettability. In addition, the present application adds fumed silica, which can improve the uniformity of the cured product. In addition, fumed silica and dicyandiamide curing agent produce a compounding effect. The dicyandiamide curing agent can improve the thixotropic effect of fumed silica and intensify the network structure of fumed silica, playing a thickening role.

[0030] 3. In the present application, the flame retardant system uses a specified amount of tetrabromobisphenol A epoxy resin and antimony trioxide, which not only has a good flame retardant effect, but also can be well dispersed in the resin matrix in the formula system of the present application and will not overly affect the Tg. In addition, the curing agent and accelerator adopted in the present application can be well applied to the multi-functional epoxy resin system with a high Tg, and can achieve rapid curing without the problem of explosive polymerization.

[0031] 4. The raw materials of the present application are easily available, the process is simple, and the cost is low, which is suitable for process promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is the viscosity-temperature curve of the rapidly cured PCM epoxy resin in Example 3;

[0033] Figure 2 is the DSC curve of the rapidly cured PCM epoxy resin in Example 3. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The following further describes the present application in detail with reference to the drawings and embodiments.

[0035] The embodiments of the present application first provide a flame retardant, high-Tg, rapidly cured epoxy resin for PCM, and the raw materials include the following components by weight:

[0036] 100 parts of multi-functional epoxy resin; the multi-functional epoxy resin is a mixture of p-aminophenol type epoxy resin and 4,4-diaminodiphenylmethane type epoxy resin. The glass transition temperature of the multi-functional epoxy resin is 240-250 °C (using DDS as the curing agent), and the epoxy equivalent is 100-125; among them, the p-aminophenol type epoxy resin and 4,4-diaminodiphenylmethane type epoxy resin can be purchased from Hubei Zhenzhengfeng New Materials Co., Ltd., and the resin models are MF-4101 and MF-3101 respectively.

[0037] 5 - 10 parts of PES toughening agent; the particle size of the PES toughening agent is 5 - 10 μm, and preferably the relative density of the PES toughening agent is 1.3 - 1.5 g / cm 3 ;

[0038] 15 - 20 parts of flame retardant;

[0039] 0.3 - 0.5 part of fumed silica; the specific surface area of the fumed silica is 90 - 100 m 2 / g;

[0040] 5.5 - 7 parts of dicyandiamide curing agent;

[0041] 1.5 - 3 parts of urea accelerator.

[0042] Furthermore, the weight ratio of p - aminophenol - type epoxy resin and 4,4 - diaminodiphenylmethane - type epoxy resin in this embodiment is (1 - 1.1):1.

[0043] Furthermore, the urea accelerator is organic urea. Specifically, the organic urea accelerator (UR500) is used in this embodiment.

[0044] Furthermore, the flame retardant is a mixture of tetrabromobisphenol A - type epoxy resin and antimony trioxide, and the weight ratio of tetrabromobisphenol A - type epoxy resin and antimony trioxide in this embodiment is (15 - 17):3.

[0045] The embodiment of the present application also provides a preparation method of a flame - retardant, high - Tg and fast - curing epoxy resin for PCM, including the following steps:

[0046] Preheat the polyfunctional epoxy resin and the PES toughening agent at 80 ± 5 °C for more than 2 h, and then raise the temperature to 170 ± 5 °C; raise the temperature of the polyfunctional epoxy resin and the PES toughening agent to 170 ± 5 °C, with a rotation speed of 100 - 200 rad / min, and keep the temperature for 2.5 - 3.5 h;

[0047] Then lower the temperature to 100 ± 5 °C, adjust the rotation speed to 300 - 400 rad / min, add fumed silica and the flame retardant, and stir for 60 - 65 min;

[0048] Lower the temperature to 80 ± 5 °C, add the dicyandiamide curing agent, and during the addition of the dicyandiamide curing agent, adjust the rotation speed to 25 ± 5 r / min; then adjust the rotation speed to 300 - 500 r / min and stir for 8 - 10 min;

[0049] After stirring is completed, lower the temperature to 60 ± 5 °C, add the urea-based accelerator. During the addition of the urea-based accelerator, adjust the rotation speed to 25 ± 5 revolutions per minute; then adjust the rotation speed to 300 - 500 revolutions per minute and stir for 5 - 8 minutes to obtain the epoxy resin.

[0050] Example 1

[0051] This example provides an epoxy resin for a flame-retardant, high-Tg fast-curing PCM. The raw materials include the following components by weight:

[0052] 100 parts of polyfunctional epoxy resin;

[0053] 5 parts of PES toughening agent;

[0054] 15 parts of flame retardant;

[0055] 0.3 part of fumed silica;

[0056] 5.5 parts of dicyandiamide curing agent;

[0057] 1.5 parts of urea-based accelerator.

[0058] Among them, the weight ratio of p-aminophenol type epoxy resin to 4,4-diaminodiphenylmethane type epoxy resin is 1:1; the weight ratio of tetrabromobisphenol A type epoxy resin to antimony trioxide in this example is 17:3.

[0059] This example also provides a preparation method of an epoxy resin for a flame-retardant, high-Tg fast-curing PCM, including the following steps:

[0060] Preheat the polyfunctional epoxy resin and the PES toughening agent at 80 ± 5 °C for 2.5 hours, and then raise the temperature to 170 ± 5 °C; raise the temperature of the polyfunctional epoxy resin and the PES toughening agent to 170 ± 5 °C, with a rotation speed of 200 rad / min, and keep the temperature for 3.5 hours;

[0061] Then lower the temperature to 100 ± 5 °C, adjust the rotation speed to 400 rad / min, and add fumed silica and the flame retardant and stir for 65 minutes;

[0062] Lower the temperature to 80 ± 5 °C, add the dicyandiamide curing agent. During the addition of the dicyandiamide curing agent, adjust the rotation speed to 25 revolutions per minute; then adjust the rotation speed to 500 revolutions per minute and stir for 10 minutes;

[0063] After stirring is completed, lower the temperature to 60 ± 5 °C, add the urea-based accelerator. During the addition of the urea-based accelerator, adjust the rotation speed to 25 revolutions per minute; then adjust the rotation speed to 500 revolutions per minute and stir for 8 minutes to obtain the epoxy resin.

[0064] Example 2

[0065] This example provides a flame-retardant, high-Tg, fast-curing epoxy resin for PCM, and the raw materials include the following components by weight parts:

[0066] 100 parts of polyfunctional epoxy resin;

[0067] 10 parts of PES toughening agent;

[0068] 15 parts of flame retardant;

[0069] 0.3 part of fumed silica;

[0070] 5.5 parts of dicyandiamide curing agent;

[0071] 1.5 parts of urea accelerator.

[0072] Among them, the weight part ratio of p-aminophenol type epoxy resin to 4,4-diaminodiphenylmethane type epoxy resin is 1:1; the weight part ratio of tetrabromobisphenol A type epoxy resin to antimony trioxide in this example is 17:3.

[0073] This example also provides a preparation method of a flame-retardant, high-Tg, fast-curing epoxy resin for PCM, including the following steps:

[0074] Preheat the polyfunctional epoxy resin and PES toughening agent at 80±5°C for 2.5 h, and then raise the temperature to 170±5°C; raise the temperature of the polyfunctional epoxy resin and PES toughening agent to 170±5°C, with a rotation speed of 200 rad / min, and keep the temperature for 3.5 h;

[0075] Then lower the temperature to 100±5°C, adjust the rotation speed to 400 rad / min, add fumed silica and flame retardant, and stir for 65 min;

[0076] Lower the temperature to 80±5°C, add dicyandiamide curing agent, and adjust the rotation speed to 25 r / min during the addition of dicyandiamide curing agent; then adjust the rotation speed to 500 r / min and stir for 10 min;

[0077] After stirring is completed, lower the temperature to 60±5°C, add urea accelerator, and adjust the rotation speed to 25 r / min during the addition of urea accelerator; then adjust the rotation speed to 500 r / min and stir for 8 min to obtain the epoxy resin.

[0078] Example 3

[0079] This example provides a flame-retardant, high-Tg, fast-curing epoxy resin for PCM, and the raw materials include the following components by weight parts:

[0080] 100 parts of polyfunctional epoxy resin;

[0081] 7 parts of PES toughening agent;

[0082] 15 parts of flame retardant;

[0083] 0.3 part of fumed silica;

[0084] 5.5 parts of dicyandiamide curing agent;

[0085] 1.5 parts of urea accelerator.

[0086] Among them, the weight ratio of p-aminophenol type epoxy resin to 4,4-diaminodiphenylmethane type epoxy resin is 1:1; the weight ratio of tetrabromobisphenol A type epoxy resin to antimony trioxide in this example is 17:3.

[0087] This example also provides a preparation method of epoxy resin for flame-retardant, high-Tg and rapid-curing PCM, including the following steps:

[0088] Preheat the polyfunctional epoxy resin and PES toughening agent at 80±5°C for 2.5 h, and then raise the temperature to 170±5°C; raise the temperature of the polyfunctional epoxy resin and PES toughening agent to 170±5°C, with a rotation speed of 200 rad / min, and keep the temperature for 3.5 h;

[0089] Then lower the temperature to 100±5°C, adjust the rotation speed to 400 rad / min, and add fumed silica and flame retardant and stir for 65 min;

[0090] Lower the temperature to 80±5°C, add dicyandiamide curing agent, and adjust the rotation speed to 25 r / min during the addition of dicyandiamide curing agent; then adjust the rotation speed to 500 r / min and stir for 10 min;

[0091] After stirring is completed, lower the temperature to 60±5°C, add urea accelerator, and adjust the rotation speed to 25 r / min during the addition of urea accelerator; then adjust the rotation speed to 500 r / min and stir for 8 min to obtain epoxy resin.

[0092] Example 4

[0093] This example provides an epoxy resin for flame-retardant, high-Tg and rapid-curing PCM, and the raw materials include the following components by weight:

[0094] 100 parts of polyfunctional epoxy resin;

[0095] 5 parts of PES toughening agent;

[0096] 20 parts of flame retardant;

[0097] 0.3 part of fumed silica;

[0098] 5.5 parts of dicyandiamide curing agent;

[0099] 1.5 parts of urea accelerator.

[0100] Among them, the weight ratio of p-aminophenol type epoxy resin to 4,4-diaminodiphenylmethane type epoxy resin is 1:1; the weight ratio of tetrabromobisphenol A type epoxy resin to antimony trioxide in this example is 17:3.

[0101] This example also provides a preparation method of a flame-retardant, high-Tg and fast-curing epoxy resin for PCM, including the following steps:

[0102] Preheat the polyfunctional epoxy resin and PES toughening agent at 80±5°C for 2.5 h, and then raise the temperature to 170±5°C; raise the temperature of the polyfunctional epoxy resin and PES toughening agent to 170±5°C, with a rotation speed of 200 rad / min, and keep the temperature for 3.5 h;

[0103] Then lower the temperature to 100±5°C, adjust the rotation speed to 400 rad / min, and add fumed silica and flame retardant and stir for 65 min;

[0104] Lower the temperature to 80±5°C, add dicyandiamide curing agent, and adjust the rotation speed to 25 r / min during the addition of dicyandiamide curing agent; then adjust the rotation speed to 500 r / min and stir for 10 min;

[0105] After stirring is completed, lower the temperature to 60±5°C, add urea accelerator, and adjust the rotation speed to 25 r / min during the addition of urea accelerator; then adjust the rotation speed to 500 r / min and stir for 8 min to obtain the epoxy resin.

[0106] Example 5

[0107] This example provides a flame-retardant, high-Tg and fast-curing epoxy resin for PCM, and the raw materials include the following components by weight:

[0108] 100 parts of polyfunctional epoxy resin;

[0109] 7 parts of PES toughening agent;

[0110] 15 parts of flame retardant;

[0111] 0.3 part of fumed silica;

[0112] 6.5 parts of dicyandiamide curing agent;

[0113] 1.5 parts of urea accelerator.

[0114] Among them, the weight ratio of p-aminophenol type epoxy resin to 4,4-diaminodiphenylmethane type epoxy resin is 1:1; the weight ratio of tetrabromobisphenol A type epoxy resin to antimony trioxide in this example is 17:3.

[0115] This example also provides a preparation method of an epoxy resin for flame-retardant and high-Tg fast-curing PCM, including the following steps:

[0116] Preheat the polyfunctional epoxy resin and PES toughening agent at 80 ± 5 °C for 2.5 h, and then raise the temperature to 170 ± 5 °C; raise the temperature of the polyfunctional epoxy resin and PES toughening agent to 170 ± 5 °C, with a rotation speed of 200 rad / min, and keep the temperature for 3.5 h;

[0117] Then lower the temperature to 100 ± 5 °C, adjust the rotation speed to 400 rad / min, and add fumed silica and flame retardant and stir for 65 min;

[0118] Lower the temperature to 80 ± 5 °C, add dicyandiamide curing agent, and adjust the rotation speed to 25 r / min during the addition of dicyandiamide curing agent; then adjust the rotation speed to 500 r / min and stir for 10 min;

[0119] After stirring is completed, lower the temperature to 60 ± 5 °C, add urea accelerator, and adjust the rotation speed to 25 r / min during the addition of urea accelerator; then adjust the rotation speed to 500 r / min and stir for 8 min to obtain the epoxy resin.

[0120] Example 6

[0121] This example provides an epoxy resin for flame-retardant and high-Tg fast-curing PCM, and the raw materials include the following components by weight:

[0122] 100 parts of polyfunctional epoxy resin;

[0123] 7 parts of PES toughening agent;

[0124] 15 parts of flame retardant;

[0125] 0.3 part of fumed silica;

[0126] 7 parts of dicyandiamide curing agent;

[0127] 1.5 parts of urea accelerator.

[0128] Among them, the weight ratio of p-aminophenol type epoxy resin to 4,4-diaminodiphenylmethane type epoxy resin is 1:1; the weight ratio of tetrabromobisphenol A type epoxy resin to antimony trioxide in this example is 17:3.

[0129] This embodiment also provides a preparation method of an epoxy resin for flame-retardant and high-Tg fast-curing PCM, comprising the following steps:

[0130] Preheat the polyfunctional epoxy resin and the PES toughening agent at 80 ± 5 °C for 2.5 h, and then raise the temperature to 170 ± 5 °C; Raise the temperature of the polyfunctional epoxy resin and the PES toughening agent to 170 ± 5 °C, with a rotation speed of 200 rad / min, and keep the temperature for 3.5 h;

[0131] Then lower the temperature to 100 ± 5 °C, adjust the rotation speed to 400 rad / min, add fumed silica and a flame retardant, and stir for 65 min;

[0132] Lower the temperature to 80 ± 5 °C, add dicyandiamide curing agent, and adjust the rotation speed to 25 r / min during the addition of the dicyandiamide curing agent; Then adjust the rotation speed to 500 r / min and stir for 10 min;

[0133] After stirring is completed, lower the temperature to 60 ± 5 °C, add a urea-based accelerator, and adjust the rotation speed to 25 r / min during the addition of the urea-based accelerator; Then adjust the rotation speed to 500 r / min and stir for 8 min to obtain the epoxy resin.

[0134] Example 7

[0135] This embodiment provides an epoxy resin for flame-retardant and high-Tg fast-curing PCM, and the raw materials include the following components in parts by weight:

[0136] 100 parts of polyfunctional epoxy resin;

[0137] 7 parts of PES toughening agent;

[0138] 15 parts of flame retardant;

[0139] 0.5 part of fumed silica;

[0140] 7 parts of dicyandiamide curing agent;

[0141] 3 parts of urea-based accelerator.

[0142] Among them, the weight part ratio of p-aminophenol type epoxy resin and 4,4-diaminodiphenylmethane type epoxy resin is 1.1:1; The weight part ratio of tetrabromobisphenol A type epoxy resin and antimony trioxide in this embodiment is 15:3.

[0143] This embodiment also provides a preparation method of an epoxy resin for flame-retardant and high-Tg fast-curing PCM, comprising the following steps:

[0144] Preheat the multi-functional group epoxy resin and the PES toughening agent at 80 ± 5°C for 3 hours, and then raise the temperature to 170 ± 5°C; Raise the temperature of the multi-functional group epoxy resin and the PES toughening agent to 170 ± 5°C, with a rotation speed of 100 rad / min, and keep the temperature for 2.5 hours;

[0145] Then lower the temperature to 100 ± 5°C, adjust the rotation speed to 300 rad / min, add fumed silica and a flame retardant, and stir for 60 minutes;

[0146] Lower the temperature to 80 ± 5°C, add dicyandiamide curing agent, and during the addition of the dicyandiamide curing agent, adjust the rotation speed to 25 revolutions / min; Then adjust the rotation speed to 300 revolutions / min and stir for 8 minutes;

[0147] After stirring is completed, lower the temperature to 60 ± 5°C, add a urea-based accelerator, and during the addition of the urea-based accelerator, adjust the rotation speed to 25 revolutions / min; Then adjust the rotation speed to 300 revolutions / min and stir for 5 minutes to obtain the epoxy resin.

[0148] Comparative Example

[0149] The difference between Comparative Example 1 and Example 1 is that no PES toughening agent is added.

[0150] The difference between Comparative Example 2 and Example 1 is that DDS is used as the curing agent

[0151] The difference between Comparative Example 3 and Example 1 is that the dosage of the flame retardant is 25 parts.

[0152] The difference between Comparative Example 4 and Example 1 is that no urea-based accelerator is added.

[0153] The difference between Comparative Example 5 and Example 1 is that core-shell rubber is used as the toughening agent, specifically MX-150 from Kaneka of Japan.

[0154] The difference between Comparative Example 6 and Example 1 is that the multi-functional epoxy resin is all p-aminophenol type epoxy resin.

[0155] The difference between Comparative Example 7 and Example 1 is that the multi-functional epoxy resin is all 4,4'-diaminodiphenylmethane type epoxy resin.

[0156] The difference between Comparative Example 8 and Example 1 is that the particle size of the PES toughening agent is 15 - 20 μm.

[0157] Performance Detection

[0158] Detect the resin performance of the examples and comparative examples according to the following method.

[0159] Vitrification temperature detection method: GB / T 19466.2.

[0160] Viscosity at 70 °C: GB / T 265;

[0161] Flame retardancy: ul94 flame retardancy standard;

[0162] Mechanical properties of the casting body: GB / T 2567.

[0163] The curing time of the prepreg is tested by hot pressing at 150 °C: Use 3k carbon fiber fabric (surface weight 300 g / m 2 ) as the reinforcing material to prepare a prepreg with a resin content of (40 ± 5)%, and conduct a small-scale test through a hot pressing test. Hot pressing test: Judge the curing condition every 1 minute within 10 minutes, and judge the curing time every 10 minutes after 10 minutes.

[0164] The test results are shown in Table 1.

[0165] Table 1 Performance test results of examples and comparative examples

[0166]

[0167] According to the performance tests of Examples 1-7, the epoxy resin for PCM prepared in this application has a Tg > 160 °C (DSC), a curing time of 5 min (150 °C), and a flame retardancy rating of UL94 V-0. Compared with the traditional system, the Tg of this application is increased and the curing time is shortened, achieving the synergy of flame retardancy and high Tg / rapid curing, with excellent performance and meeting the performance requirements of the PCM roof crossbeam. In addition, the raw materials of this application are easily available, the process is simple, and the cost is low, making it suitable for process promotion.

[0168] Combined with the performance results of Comparative Example 1, it was found that no toughening agent was added in Comparative Example 1, and its flexural strength decreased significantly, indicating that the toughening agent has a direct toughening effect. In addition, from the viscosity comparison between Comparative Example 1 and the Examples, it can be found that after adding the specific toughening agent of the present application to the resin system, it can not only achieve the toughening effect, but also be used in combination with a specific multi-functional epoxy resin to play a role in viscosity adjustment, which is beneficial to subsequent infiltration. Further analysis of the performance of Examples 1-3 shows that as the dosage of the toughening agent increases, although the flexural strength of the resin increases, the viscosity will also be affected and increase. Therefore, the use of an appropriate amount of toughening agent is very important. Combining with the findings of Comparative Example 5, for the use of toughening agents, not all toughening agents can act well on the resin system of the present application. Although the toughening agent used in Comparative Example 5 can also achieve the toughening effect, it will affect the glass transition temperature of the resin system and also cause the viscosity of the resin system to be too small, which is not conducive to the infiltration of the resin. In addition, combining with the performance findings of Comparative Example 8, for the PES toughening agent used in the present application, the appropriate particle size also has a great impact on the performance of the resin. When the particle size is 5-10 μm, the resin performance is the most excellent.

[0169] Analysis of the performance of Comparative Examples 2-3 shows that as functional resins, the types or dosages of the curing agent, flame retardant and accelerator have different degrees of influence on the performance of the resin. For the resin system of the present application, the specified reagent dosages and types can not only play the functional roles of the reagents themselves, but also are beneficial to the improvement of the comprehensive performance of the resin.

[0170] For the composite epoxy resin, its matrix resin also has a crucial impact on its final performance. In particular, the base resin of the present application is a mixture of p-aminophenol type epoxy resin and 4,4-diaminodiphenylmethane type epoxy resin. Combining the performance of Comparative Example 6 and Comparative Example 7, it can be seen that it is preferable to use the high-Tg multi-functional epoxy resin of the present application, which is beneficial to the comprehensive improvement of the resin performance.

[0171] This specific embodiment is only an interpretation of the present application and does not limit the present application. Those skilled in the art can make modifications without creative contributions to this embodiment after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A flame retardant, high Tg, fast curing epoxy resin for PCM, characterized in that: The raw materials include the following components by weight: 100 parts of a multifunctional epoxy resin; the multifunctional epoxy resin is a mixture of a p-aminophenol epoxy resin and a 4,4-diaminodiphenylmethane epoxy resin, the glass transition temperature of the multifunctional epoxy resin is 240-250° C., and the epoxy equivalent is 100-125; 5-10 parts of PES toughening agent; the particle size of the PES toughening agent is 5-10 μm; Flame retardant 15-20 parts; 0.3-0.5 parts of fumed silica; the specific surface area of ​​the fumed silica is 90-100m 2 / g; 5.5-7 parts of dicyandiamide curing agent; 1.5-3 parts of urea accelerator.

2. A flame retardant, high Tg, fast curing epoxy resin for PCM according to claim 1, characterized in that: The weight ratio of the p-aminophenol type epoxy resin to the 4,4-diaminodiphenylmethane type epoxy resin is (1-1.1):

1.

3. The flame retardant, high Tg, fast curing epoxy resin for PCM according to claim 1, characterized in that: The relative density of the PES toughening agent is 1.3-1.5 g / cm 3 .

4. The flame retardant, high Tg, fast curing epoxy resin for PCM according to claim 1, characterized in that: The urea accelerator is organic urea.

5. The flame retardant, high Tg, fast curing epoxy resin for PCM according to claim 1, characterized in that: The flame retardant is a mixture of tetrabromobisphenol A epoxy resin and antimony trioxide, and the weight ratio of the tetrabromobisphenol A epoxy resin to antimony trioxide is (15-17):

3.

6. A method for preparing a flame retardant, high Tg, fast curing epoxy resin for PCM according to any one of claims 1 to 5, characterized in that: The following steps are involved: Raise the temperature of the multifunctional epoxy resin and PES toughening agent to 170±5°C, rotate at 100-200 rad / min, and keep warm for 2.5-3.5 hours; Then lower the temperature to 100±5℃, adjust the speed to 300-400rad / min, add fumed silica and flame retardant and stir for 60-65min; Lower the temperature to 80±5℃, add dicyandiamide curing agent, rotate at 300-500 rpm, and stir for 8-10 minutes; After the stirring is completed, the temperature is lowered to 60±5° C., a urea accelerator is added, the rotation speed is 300-500 rpm, and the stirring is performed for 5-8 minutes to obtain the epoxy resin.

7. The method for preparing a flame retardant, high Tg, fast curing epoxy resin for PCM according to claim 6, characterized in that: The following steps are involved: Preheat the multifunctional epoxy resin at 80±5°C for more than 2 hours, and then raise the temperature to 170±5°C.

8. The method for preparing a flame retardant, high Tg, fast curing epoxy resin for PCM according to claim 6, characterized in that: During the addition of dicyandiamide curing agent, the rotation speed was adjusted to 25±5 rpm.

9. The method for preparing a flame retardant, high Tg, fast curing epoxy resin for PCM according to claim 6, characterized in that: During the addition of the urea accelerator, the rotation speed was adjusted to 25±5 rpm.

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