Fast curing epoxy resin system for large-tow carbon fiber prepreg and preparation method

Abstract

The invention discloses a fast curing epoxy resin system for large-tow carbon fiber prepreg and a preparation method. The fast curing epoxy resin system comprises a component A and a component B, the component A comprises bisphenol A type epoxy resin, bisphenol F type epoxy resin, alicyclic epoxy resin, polymethyl acrylate, a defoaming agent, a dispersing agent and an antioxidant; the component B comprises dicyandiamide, a UR500 accelerant, modified polyether amine and liquid epoxy resin. The epoxy resin system disclosed by the invention can be rapidly cured for 6-15 minutes at 120 DEG C, and meanwhile, the mechanical property of a workpiece is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly relates to a fast-curing epoxy resin system for large tow carbon fiber prepregs and a preparation method thereof. Background Art

[0002] Due to its excellent properties such as high specific strength, high specific modulus, and corrosion resistance, carbon fiber reinforced composites have been widely used in the fields of aerospace, automotive manufacturing, wind power generation, etc. At present, large tow carbon fibers (usually referring to carbon fibers of 24K and above) have gradually gained market favor due to their lower cost. However, when the existing epoxy resin systems are infiltrated with large tow carbon fibers, the following technical problems exist:

[0003] 1. Slow curing speed: The existing epoxy resin systems have a slow curing speed, which affects the production efficiency of subsequent parts.

[0004] 2. Insufficient permeability: The existing epoxy resin systems have a relatively high viscosity, making it difficult to effectively infiltrate large tow carbon fibers, resulting in poor interfacial bonding strength.

[0005] 3. Poor fluidity: The existing epoxy resin systems have poor fluidity at medium temperatures, which is not conducive to the uniform distribution and infiltration of large tow carbon fiber bundles, affecting the processing quality of prepregs.

[0006] 4. High curing temperature: Some of the existing epoxy resin systems have a high curing temperature, which increases the processing energy consumption and may affect the mechanical properties of the final composite material.

[0007] 5. Poor storage stability: Some of the existing epoxy resin systems are prone to chemical reactions or viscosity changes during storage, affecting their long-term use stability.

[0008] Therefore, developing a fast-curing epoxy resin system for large tow carbon fiber prepregs to improve its wettability, fluidity, curing performance, and storage stability has important technical value and application prospects. Summary of the Invention

[0009] Aiming at the deficiencies in the existing technology, the present invention provides a fast-curing epoxy resin system for large tow carbon fiber prepregs and a preparation method thereof, to improve its wettability, fluidity, curing performance, and storage stability, which has important technical value and application prospects.

[0010] The present invention discloses a fast-curing epoxy resin system for large tow carbon fiber prepregs, including: component A and component B;

[0011] Component A includes bisphenol A epoxy resin, bisphenol F epoxy resin, alicyclic epoxy resin, polymethyl acrylate, defoamer, dispersant, and antioxidant;

[0012] The component B includes dicyandiamide, accelerator UR500, modified polyetheramine and liquid epoxy resin.

[0013] As a further improvement of the present invention, the proportion of the component B to the component A is 5wt% - 15wt%, preferably 5wt% - 10wt%.

[0014] As a further improvement of the present invention, by weight, the component A includes:

[0015] 30 - 60 parts by weight of bisphenol A epoxy resin;

[0016] 30 - 60 parts by weight of bisphenol F epoxy resin;

[0017] 10 - 30 parts by weight of alicyclic epoxy resin;

[0018] 5 - 20 parts by weight of polymethyl acrylate;

[0019] 0.1 - 1 part by weight of defoamer;

[0020] 0.2 - 0.8 part by weight of dispersant;

[0021] 0.1 - 1 part by weight of antioxidant.

[0022] As a further improvement of the present invention, by weight, the component B includes:

[0023] 40 - 60 parts by weight of dicyandiamide;

[0024] 35 - 55 parts by weight of accelerator UR500;

[0025] 3 - 5 parts by weight of modified polyetheramine;

[0026] 1 - 5 parts by weight of liquid epoxy resin.

[0027] The present invention also discloses a preparation method of a fast - curing epoxy resin system for large - tow carbon fiber prepreg, including:

[0028] Step 1: Weigh and mix bisphenol A epoxy resin, bisphenol F epoxy resin and alicyclic epoxy resin in the component A, heat the mixture to 60 - 80°C, after fully mixing, add the weighed polymethyl acrylate, defoamer, dispersant and antioxidant, and stir evenly; stir at a stirring speed of 375 - 1000 rmp for 20 - 30 minutes to make them fully melt and mix. After sufficient reaction, reduce the rotation speed to 20 - 50 rpm and continue to stir for 5 - 15 minutes to obtain the mixture of the component A;

[0029] Step 2: After accurately weighing the UR500 accelerator, modified polyetheramine and dicyandiamide in component B, first grind the dicyandiamide into powder and sieve it so that its particle diameter is less than or equal to 10 microns; then use the UR500 accelerator as the main accelerator and the modified polyetheramine as the secondary accelerator, mix them with the dicyandiamide curing agent, add a certain amount of liquid epoxy resin to adjust the viscosity, and fully grind them using a grinder to obtain a mixture of component B;

[0030] Step 3: wait for component A to cool down to 60-80°C, add component B to component A, stir at a stirring speed of 1200-1600 rpm for 25-35 minutes to fully melt and mix, wait until it is fully reacted, reduce the speed to 30-50 rpm, continue stirring for 10-20 minutes to fully stir, take samples for testing, filter in a filtration device after passing the test, wait for it to cool to room temperature for packaging, and finally obtain the epoxy resin system.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. Rapid curing: The epoxy resin system of the present invention can achieve rapid curing of 6 to 15 minutes at 120°C, which greatly shortens the curing time and improves production efficiency compared to traditional epoxy resin systems.

[0033] 2. Excellent mechanical properties: The epoxy resin system of the present invention has excellent mechanical properties by optimizing the resin formula, making it more suitable for the field of high-strength composite materials.

[0034] 3. Improve resin wettability: The epoxy resin system of the present invention adopts a specific proportion of formulated resin to improve the resin wettability of large-tow carbon fibers, reduce dry fiber areas, and improve the stability of prepreg production.

[0035] 4. The preparation method provided by the present invention is simple and efficient, and can be applied to the stable batch production of prepreg. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention discloses a flow chart of a method for preparing a fast-curing epoxy resin system for large-tow carbon fiber prepreg. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The present invention will be further described in detail below with reference to the accompanying drawings:

[0039] The present invention discloses a fast-curing epoxy resin system for large tow carbon fiber prepregs, comprising: component A and component B, and the proportion of component B in component A is 5 wt% to 15 wt%, preferably 5 wt% to 10 wt%;

[0040] By weight, the component A includes:

[0041] 30 to 60 parts by weight of bisphenol A epoxy resin;

[0042] 30 to 60 parts by weight of bisphenol F epoxy resin;

[0043] 10 to 30 parts by weight of alicyclic epoxy resin;

[0044] 5 to 20 parts by weight of polymethyl acrylate;

[0045] 0.1 to 1 part by weight of defoamer;

[0046] 0.2 to 0.8 part by weight of dispersant;

[0047] 0.1 to 1 part by weight of antioxidant.

[0048] As a further improvement of the present invention, by weight, the component B includes:

[0049] 40 to 60 parts by weight of dicyandiamide;

[0050] 35 to 55 parts by weight of UR500 accelerator;

[0051] 3 to 5 parts by weight of modified polyetheramine;

[0052] 1 to 5 parts by weight of liquid epoxy resin.

[0053] As Figure 1 shown, the present invention provides a preparation method of a fast-curing epoxy resin system for large tow carbon fiber prepregs, comprising:

[0054] Step 1: Weigh the bisphenol A epoxy resin, bisphenol F epoxy resin and alicyclic epoxy resin in component A, mix and heat them to 60 to 80 °C. After fully mixing, add the weighed polymethyl acrylate, defoamer, dispersant and antioxidant, and stir evenly; stir at a stirring speed of 375 to 1000 rmp for 20 to 30 minutes to make them fully melt and mix. After sufficient reaction, reduce the rotation speed to 20 to 50 rpm and continue to stir for 5 to 15 minutes to obtain a mixture of component A;

[0055] Step 2: After accurately weighing the UR500 accelerator, modified polyetheramine and dicyandiamide in component B, first grind the dicyandiamide into powder and sieve it so that its particle diameter is less than or equal to 10 microns; then use the UR500 accelerator as the main accelerator and the modified polyetheramine as the secondary accelerator, mix them with the dicyandiamide curing agent, add a certain amount of liquid epoxy resin to adjust the viscosity, and fully grind them using a grinder to obtain a mixture of component B;

[0056] Step 3: wait for component A to cool down to 60-80°C, add component B to component A, stir at a stirring speed of 1200-1600 rpm for 25-35 minutes to fully melt and mix, wait until it is fully reacted, reduce the speed to 30-50 rpm, continue stirring for 10-20 minutes to fully stir, take samples for testing, filter in a filtration device after passing the test, wait for it to cool to room temperature for packaging, and finally obtain the epoxy resin system.

[0057] Example 1

[0058] A fast curing epoxy resin system for large tow carbon fiber prepreg is prepared by combining two components A and B, wherein the proportion of component B to component A is 5wt%; wherein:

[0059] Component A includes the following ingredients in parts by weight:

[0060] 40 parts by weight of bisphenol A epoxy resin;

[0061] 40 parts by weight of bisphenol F epoxy resin;

[0062] 12 parts by weight of alicyclic epoxy resin;

[0063] 6 parts by weight of polymethyl acrylate;

[0064] 1 part by weight of defoamer;

[0065] Dispersant 0.8 parts by weight;

[0066] 0.2 parts by weight of antioxidant;

[0067] Component B includes the following ingredients in parts by weight:

[0068] 60 parts by weight of dicyandiamide;

[0069] UR500 accelerator 35 parts by weight;

[0070] 4 parts by weight of modified polyetheramine;

[0071] 1 part by weight of liquid epoxy resin;

[0072] The method for preparing the above-mentioned fast curing epoxy resin system for large tow carbon fiber prepreg comprises the following steps:

[0073] S11. Weigh the bisphenol A epoxy resin, bisphenol F epoxy resin, and alicyclic epoxy resin in component A, mix and heat them to 80 °C. After thorough mixing, add the weighed polymethyl acrylate, defoaming agent, dispersant, and antioxidant, and stir evenly to make them fully melt and mix. Stir at a stirring speed of 1000 rmp for 30 minutes to make them fully melt and mix. After sufficient reaction, reduce the speed to 50 rpm and continue stirring for 15 minutes to obtain the mixture of component A.

[0074] S12. Accurately weigh the UR500 accelerator, modified polyetheramine, and dicyandiamide in component B. First, grind the dicyandiamide into powder and sieve it so that its particle diameter is less than or equal to 10 microns. Then, use the UR500 accelerator as the main accelerator, the modified polyetheramine as the secondary accelerator, mix them with the dicyandiamide curing agent, and add a certain amount of liquid epoxy resin to adjust the viscosity. Grind them thoroughly with a grinder to obtain the mixture of component B.

[0075] S13. Wait for A to cool down to 60 °C, add B to A, and stir at a stirring speed of 1600 rmp for 35 minutes to make them fully melt and mix. After sufficient reaction, reduce the speed to 50 rpm and continue stirring for 20 minutes to stir evenly. Take samples for testing. After passing the test, filter them in a filtering device, wait for them to cool down to room temperature for encapsulation, and finally obtain the epoxy resin system.

[0076] Example 2

[0077] A fast-curing epoxy resin system for large tow carbon fiber prepreg is prepared from two components A and B, and the proportion of component B in component A is 6 wt%. Among them,

[0078] Component A includes the following components in parts by weight:

[0079] 40 parts by weight of bisphenol A epoxy resin;

[0080] 30 parts by weight of bisphenol F epoxy resin;

[0081] 22 parts by weight of alicyclic epoxy resin;

[0082] 6 parts by weight of polymethyl acrylate;

[0083] 1 part by weight of defoaming agent;

[0084] 0.3 part by weight of dispersant;

[0085] 0.7 part by weight of antioxidant;

[0086] Component B includes the following components in parts by weight:

[0087] 60 parts by weight of dicyandiamide;

[0088] 35 parts by weight of accelerator UR500;

[0089] 4 parts by weight of modified polyetheramine;

[0090] 1 part by weight of liquid epoxy resin;

[0091] The preparation method of the fast-curing epoxy resin system for the above large tow carbon fiber prepreg includes the following steps:

[0092] S21. Weigh bisphenol A epoxy resin, bisphenol F epoxy resin, and alicyclic epoxy resin in component A, mix and heat them to 80 °C. After thorough mixing, add the weighed polymethyl acrylate, defoamer, dispersant, and antioxidant, and stir evenly to make them fully melt and mix. Stir at a stirring speed of 375 rmp for 20 minutes to make them fully melt and mix. After the reaction is complete, reduce the speed to 20 rpm and continue stirring for 5 minutes to obtain the mixture of component A.

[0093] S22. Accurately weigh the accelerator UR500, modified polyetheramine, and dicyandiamide in component B. First, grind dicyandiamide into powder and sieve it so that the particle diameter is less than or equal to 10 microns. Then, use accelerator UR500 as the main accelerator, modified polyetheramine as the secondary accelerator, mix with the dicyandiamide curing agent, and add a certain amount of liquid epoxy resin to adjust the viscosity. Use a grinder to grind thoroughly to obtain the mixture of component B.

[0094] S23. Wait for A to cool down to 80 °C, add B to A, and stir at a stirring speed of 1200 rmp for 25 minutes to make them fully melt and mix. After the reaction is complete, reduce the speed to 30 rpm and continue stirring for 10 minutes to stir evenly. Take a sample for testing. After passing the test, filter it in a filtering device, wait for it to cool to room temperature for encapsulation, and finally obtain the epoxy resin system.

[0095] Example 3

[0096] A fast-curing epoxy resin system for large tow carbon fiber prepreg is prepared from components A and B together, and the proportion of component B in component A is 5 wt%; among them,

[0097] Component A includes the following components in parts by weight:

[0098] 40 parts by weight of bisphenol A epoxy resin;

[0099] 30 parts by weight of bisphenol F epoxy resin;

[0100] 20 parts by weight of alicyclic epoxy resin;

[0101] 8 parts by weight of polymethyl acrylate;

[0102] 1 part by weight of defoamer;

[0103] 0.8 part by weight of dispersant;

[0104] 0.2 part by weight of antioxidant;

[0105] Component B includes the following components by weight:

[0106] 60 parts by weight of dicyandiamide;

[0107] 35 parts by weight of UR500 accelerator;

[0108] 4 parts by weight of modified polyetheramine;

[0109] 1 part by weight of liquid epoxy resin.

[0110] The preparation method of the above-mentioned fast-curing epoxy resin system for large tow carbon fiber prepreg includes the following steps:

[0111] S31. Weigh bisphenol A epoxy resin, bisphenol F epoxy resin, and alicyclic epoxy resin in component A, mix and heat them to 80 °C. After fully mixing, add the weighed polymethyl acrylate, defoamer, dispersant, and antioxidant, stir evenly to make them fully melt and mix, stir at a stirring speed of 685 rmp for 25 minutes to make them fully melt and mix. After the full reaction, reduce the speed to 35 rpm and continue to stir for 10 minutes to obtain the mixture of component A.

[0112] S32. Accurately weigh UR500 accelerator, modified polyetheramine, and dicyandiamide in component B. First, grind dicyandiamide into powder and sieve it to make its particle diameter less than or equal to 10 microns. Then, use UR500 accelerator as the main accelerator and modified polyetheramine as the auxiliary accelerator, mix with dicyandiamide curing agent, and add a certain amount of liquid epoxy resin to adjust the viscosity, and use a grinder to fully grind to obtain the mixture of component B.

[0113] S33. Wait for A to cool down to 80 °C, add B to A, stir at a stirring speed of 1400 rmp for 30 minutes to make them fully melt and mix. After the full reaction, reduce the speed to 40 rpm and continue to stir for 15 minutes to stir evenly. Take samples for testing. After passing the test, filter in a filtering device, wait for it to cool to room temperature and then package it to finally obtain the epoxy resin system.

[0114] Comparative Example 1

[0115] Medium-temperature fast-curing epoxy resin 1 purchased from the market.

[0116] Comparative Example 2

[0117] Medium-temperature fast-curing epoxy resin 2 purchased from the market.

[0118] The performance of the products provided in Examples 1 to 3 and Comparative Examples 1 to 2 was tested, specifically including:

[0119] Curing speed test: Gel meter, 120 ± 5 °C, comparing the gel time and the curing time; the one with a shorter time is better, Table 1;

[0120] Table 1 Gel time

[0121]

[0122] Prepreg performance test: Prepared with 48K (Shanghai Petrochemical) carbon fiber, resin content 33%, fiber areal density 600 g / m 2 , the composite material performance is shown in Table 2

[0123] Table 2 Mechanical properties of composite materials

[0124] Test item Experimental example 1 Experimental example 2 Experimental example 3 Comparative example 1 Comparative example 2 Flexural strength at 0 degrees 1455 1355 1402 1342 1223 Flexural modulus at 0 degrees 132 131 131 128 131 Interlaminar strength at 0 degrees 88 89 85 71 70

[0125] It can be seen from Table 1 and Table 2 that compared with Comparative Examples 1 to 2, Examples 1 to 3 have a faster curing speed, a shorter time, and higher mechanical properties of the composite material.

[0126] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A fast-curing epoxy resin system for large tow carbon fiber prepregs, characterized in that, Comprising: Component A and Component B; Component A includes bisphenol A epoxy resin, bisphenol F epoxy resin, alicyclic epoxy resin, polymethyl acrylate, defoamer, dispersant and antioxidant; Component B includes dicyandiamide, UR500 accelerator, modified polyetheramine and liquid epoxy resin.

2. The fast-curing epoxy resin system for large tow carbon fiber prepregs according to claim 1, wherein The proportion of Component B in Component A is 5wt% - 15wt%.

3. The fast-curing epoxy resin system for large tow carbon fiber prepregs according to claim 1 or 2, characterized in that, By weight, Component A includes: 30 - 60 parts by weight of bisphenol A epoxy resin; 30 - 60 parts by weight of bisphenol F epoxy resin; 10 - 30 parts by weight of alicyclic epoxy resin; 5 - 20 parts by weight of polymethyl acrylate; 0.1 - 1 part by weight of defoamer; 0.2 - 0.8 part by weight of dispersant; 0.1 - 1 part by weight of antioxidant.

4. The fast-curing epoxy resin system for large tow carbon fiber prepreg according to claim 1 or 2, characterized in that, By weight, Component B includes: 40 - 60 parts by weight of dicyandiamide; 35 - 55 parts by weight of UR500 accelerator; 3 - 5 parts by weight of modified polyetheramine; 1 - 5 parts by weight of liquid epoxy resin.

5. A preparation method of a fast-curing epoxy resin system for large tow carbon fiber prepreg as described in any one of claims 1 to 4, characterized in that, Comprising: Step 1: Weigh the bisphenol A epoxy resin, bisphenol F epoxy resin and alicyclic epoxy resin in Component A, mix and heat them to 60 - 80 °C. After fully mixing, add the weighed polymethyl acrylate, defoamer, dispersant and antioxidant, and stir evenly. Stir at a stirring speed of 375 - 1000 rmp for 20 - 30 minutes to make them fully melt and mix. After sufficient reaction, reduce the speed to 20 - 50 rpm and continue to stir for 5 - 15 minutes to obtain the mixture of Component A; Step 2: Accurately weigh the UR500 accelerator, modified polyetheramine and dicyandiamide in Component B. First, grind the dicyandiamide into powder and sieve it so that the particle diameter is less than or equal to 10 microns. Then, use the UR500 accelerator as the main accelerator and the modified polyetheramine as the secondary accelerator, mix them with the dicyandiamide curing agent, and add a certain amount of liquid epoxy resin to adjust the viscosity. Use a grinder to fully grind to obtain the mixture of Component B; Step 3: Wait for Component A to cool down to 60 - 80 °C, add Component B to Component A, stir at a stirring speed of 1200 - 1600 rmp for 25 - 35 minutes to make them fully melt and mix. After sufficient reaction, reduce the speed to 30 - 50 rpm and continue to stir for 10 - 20 minutes to stir evenly. Take samples for testing. After passing the test, filter in a filtering device, wait for it to cool to room temperature for encapsulation, and finally obtain the epoxy resin system.

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