Epoxy resin composition as well as preparation method and application thereof

Abstract

The invention discloses an epoxy resin composition as well as a preparation method and application thereof, and relates to the technical field of epoxy resin materials, the epoxy resin composition comprises an epoxy resin mixture A and a curing agent mixture B, and the mass ratio of the epoxy resin mixture A to the curing agent mixture B is 100: (85-115); wherein the epoxy resin mixture A comprises the following components in parts by mass: 50-90 parts of epoxy resin, 0-10 parts of a diluent, 5-20 parts of a toughening agent and 0.1-3 parts of an auxiliary agent; the curing agent mixture B comprises the following components in parts by mass: 50-90 parts of an anhydride curing agent, 10-30 parts of a toughening agent, 0.5-3 parts of an accelerant and 1-2 parts of a stripping-free auxiliary agent; the invention also provides a preparation method of the epoxy resin composition and application of the epoxy resin composition in pultrusion plates.

Description

Technical Field

[0001] The present invention relates to the technical field of epoxy resin materials, and particularly relates to an epoxy resin composition, a preparation method thereof, and an application thereof. Background Art

[0002] The pultrusion process is a technology widely used in the forming and processing of fiber-reinforced resin-based composites, and has important applications particularly in the fields of wind turbine blades, photovoltaic brackets, building window frames, etc. The pultrusion process can efficiently produce composite profiles with high strength and high fiber content through a continuous forming method. In recent years, with the rapid development of the wind power industry, the application of pultruded plates in the main beams of wind turbine blades has increased significantly. The pultrusion process can not only improve production efficiency, but also facilitate the replacement of a single pultruded plate when defects occur without having to process the entire main beam, thereby reducing production costs and maintenance difficulties.

[0003] However, traditional pultrusion processes usually require the use of release fabrics and internal release agents during the forming process to ensure demolding performance and the surface quality of the plates. The release fabric can improve the demolding performance of the pultruded resin system material and increase the surface energy of the plate through the unevenness of its surface, thereby enhancing the bonding performance with the subsequent casting resin. However, the use of release fabrics and internal release agents not only increases production costs, but also brings additional process complexity and quality defects. If the release fabric is not used, the surface of the formed plate will become very smooth, the surface energy will decrease, resulting in a significant drop in the bonding performance with the casting resin, and thus affecting the mechanical properties of the final product.

[0004] To solve this problem, some pultruded resin system materials without release fabrics and internal release agents have been proposed in the prior art. For example, in the patent document CN116535820B, a pultruded epoxy anhydride resin system material is disclosed, which improves the demolding performance and the surface quality of the plate through a specific toughener combination (such as polyol M and polyol N) to achieve the purpose of removing the release fabric and the internal release agent. By adjusting the proportion of the toughener, this technology can still maintain good demolding performance and bonding performance with the casting resin when the release fabric and the internal release agent are removed, thereby reducing production costs.

[0005] Nevertheless, the existing pultruded resin system materials without release fabrics and internal release agents still face some challenges during high-speed pultrusion forming. With the increase in pultrusion speed, the problems of resin infiltration and interfacial bonding with fibers become more prominent. The resin system material not only needs to be completely infiltrated with fibers in a short time, but also needs to be rapidly cured at high temperature and ensure strong interfacial bonding between fibers and resin. Therefore, developing an epoxy resin system material that can not only meet the requirements of high-speed pultrusion forming, but also maintain excellent performance under the conditions of without release fabric and internal release agent, is still an important research direction in the current technical field. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the present invention provides an epoxy resin composition, a preparation method thereof, and an application thereof, which solve the problem that the existing epoxy resin composition in the prior art cannot maintain good process performance and mechanical properties under high-speed pultrusion conditions.

[0007] An epoxy resin composition includes an epoxy resin mixture A and a curing agent mixture B, and the mass ratio of the epoxy resin mixture A to the curing agent mixture B is 100:85 to 115;

[0008] Among them, by mass, the epoxy resin mixture A includes: 50 to 90 parts of epoxy resin, 0 to 10 parts of diluent, 5 to 20 parts of toughening agent, and 0.1 to 3 parts of auxiliary agent;

[0009] By mass, the curing agent mixture B includes: 50 to 90 parts of acid anhydride curing agent, 10 to 30 parts of toughening agent, 0.5 to 3 parts of accelerator, and 1 to 2 parts of non-removal auxiliary agent.

[0010] Preferably, the mass ratio of the diluent to the toughening agent in the epoxy resin mixture A is 0 to 10:5 to 20.

[0011] Preferably, the epoxy resin is at least one of bisphenol A type epoxy resin and bisphenol F type epoxy resin;

[0012] The diluent is one or more of polyethylene glycol diglycidyl ether, glycerol triglycidyl ether, and phenyl glycidyl ether;

[0013] The toughening agent in the epoxy resin mixture A is a sea-island structure toughening agent;

[0014] The auxiliary agent is one or more of a coupling agent, an antifoaming agent, and a wetting agent.

[0015] Preferably, the acid anhydride curing agent is at least one of methyltetrahydrophthalic anhydride and methylhexahydrophthalic anhydride;

[0016] The toughening agent in the curing agent mixture B is composed of polyether polyol and polyetheramine in a mass ratio of 3 to 11:7 to 17;

[0017] The accelerator is one or more of quaternary ammonium salts, imidazoles, and imidazole salts.

[0018] Preferably, the epoxy resin is one or more of E-51, E-54, and F-51.

[0019] Preferably, the mass ratio of the polyether polyol to the polyetheramine is 5 to 10:8 to 15.

[0020] Preferably, the polyether polyol is polytetrahydrofuran ether diol, and the polyetheramine is one of D2000 and T5000.

[0021] Preferably, the main structural formula of the non-removal aid is:

[0022] The present invention also provides a preparation method of an epoxy resin composition, comprising the following steps:

[0023] S1. Take epoxy resin, diluent, toughening agent and auxiliary agent, mix them evenly to obtain epoxy resin mixture A;

[0024] S2. Take acid anhydride curing agent, toughening agent, accelerator and non-removal aid, mix them evenly to obtain curing agent mixture B;

[0025] S3. Mix and cure the epoxy resin mixture A prepared in S1 and the curing agent mixture B prepared in S2 according to a mass ratio of 100:85-115 to obtain the epoxy resin composition.

[0026] The present invention also provides an application of the epoxy resin composition in pultruded plates.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The epoxy resin mixture A in the epoxy resin composition prepared by the present invention contains a sea-island structure toughening agent, which can form a stable toughness structure during the curing process. Under the stress condition, the sea-island particles in the sea-island structure act as stress concentrators, absorb energy to generate crazes, and at the same time, under the action of the stress field, the sea-island particles interfere with each other and can reduce the energy diffusion at the craze tip, delaying the development of the craze to a crack, so that the cast body of the epoxy resin composition has good toughness and impact resistance.

[0029] 2. The curing agent mixture B in the epoxy resin composition prepared by the present invention mainly uses a macromolecular toughening agent composed of a polypropylene oxide compound capped with a primary amino group. This polyetheramine substance has a long-chain structure, and the end of the molecular chain has a highly active primary amino group. During the pultrusion process, it can react with both the epoxy resin in the epoxy resin mixture A and the active groups on the fiber surface, and form a strong interfacial bond through chemical reactions at the interface between the fiber and the resin. At the same time, the polyetheramine with a long-chain structure and the polyether polyol have a synergistic promoting effect on the toughening agent in the epoxy resin mixture A during the curing process, making the network structure with a higher crosslinking degree formed during the curing process, further delaying the development of the craze to a crack during the stress process, improving the toughness and impact resistance of the cast body of the epoxy resin composition, so that the pultruded profiles using glass fiber to reinforce the epoxy resin composition have excellent mechanical properties and fatigue resistance.

[0030] 3. The accelerator contained in the epoxy resin composition prepared by the present invention is difficult to form an active center at low temperature, but can quickly form an active center at high temperature to initiate the reaction between the epoxy resin mixture A and the curing agent mixture B. This enables the epoxy resin composition to be used for a long time at low temperature, but can quickly undergo a curing reaction when entering the mold, meeting the requirements of pultrusion forming of profiles with complex cross-sections.

[0031] 4. The non-release aid contained in the epoxy resin composition prepared by the present invention is a polymer aid developed according to the requirements of non-release cloth and non-internal release agent. This aid contains a large number of ether bonds and has hydroxyl groups at the ends, with good oleophobic and hydrophilic properties. Its surface tension is close to that of traditional internal release agents and can be evenly dispersed in the epoxy resin composition. During the pultrusion process, a part of the active groups at the ends of the non-release aid reacts with the epoxy resin mixture A to form a stable cross-linked structure, and a part of the groups overflow the surface of the plate, which can help the plate have good demolding properties under high-speed pultrusion conditions. At the same time, this part of the overflowing active groups can be effectively combined with the casting resin during secondary casting, and the addition of the non-release aid does not affect the curing reaction of the epoxy resin mixture.

[0032] Other advantages, objectives, and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. Detailed Embodiments

[0033] In order to make the technical means, creative features, achieved objectives, and functions of the present invention clearer and easier to understand, the present invention will be further described below in conjunction with specific embodiments:

[0034] Example 1

[0035] S1. At 60°C, 30 g of E-51 and 60 g of F-51 were stirred at a rotation speed of 50 rpm until the viscosity was lower than 1000 mPa·s. Then, 10 g of sea-island structure toughening agent, 0.3 g of coupling agent, and 0.3 g of defoaming agent were added, and stirring was continued for 1 h to obtain the epoxy resin mixture A;

[0036] S2. At 25°C, 90 g of methyltetrahydrophthalic anhydride was stirred at 30 rpm, then 5 g of polytetrahydrofuran ether diol and 8 g of D2000 were added. After stirring for 15 min, 1.8 g of imidazole accelerator was slowly added. After stirring for 0.5 h, 2 g of non-release aid was added, and stirring was continued for 0.5 h to obtain the curing agent mixture B;

[0037] S3. Mix the epoxy resin mixture A prepared in S1 and the curing agent mixture B prepared in S2 at a mass ratio of 100:85, stir evenly, and then remove the bubbles by vacuum degassing to obtain an epoxy resin composition.

[0038] Example 2

[0039] S1. At 60 °C, stir 50 g of E-54 at a speed of 50 rpm until the viscosity is lower than 1000 mPa·s, then add 2 g of polyethylene glycol diglycidyl ether, 3 g of glycerol triglycidyl ether, 20 g of sea-island structure toughening agent, 1 g of coupling agent, 1 g of defoaming agent and 1 g of wetting agent, and continue to stir for 1 h to obtain epoxy resin mixture A;

[0040] S2. At 50 °C, stir 50 g of methylhexahydrophthalic anhydride at 30 rpm, then add 7 g of polytetrahydrofuran ether glycol and 12 g of T5000, stir for 15 min, slowly add 3 g of quaternary ammonium salt accelerator, add 1 g of non-removal aid after stirring for 0.5 h, and continue to stir for 0.5 h to obtain curing agent mixture B;

[0041] S3. Mix the epoxy resin mixture A prepared in S1 and the curing agent mixture B prepared in S2 at a mass ratio of 100:93, stir evenly, and then remove the bubbles by vacuum degassing to obtain an epoxy resin composition.

[0042] Example 3

[0043] S1. At 60 °C, stir 35 g of E-54 and 40 g of E-51 at a speed of 50 rpm until the viscosity is lower than 1000 mPa·s, then add 10 g of phenyl glycidyl ether, 5 g of sea-island structure toughening agent, 0.1 g of wetting agent, and continue to stir for 1 h to obtain epoxy resin mixture A;

[0044] S2. At 100 °C, stir 40 g of methyltetrahydrophthalic anhydride and 40 g of methylhexahydrophthalic anhydride at 30 rpm, then add 10 g of polytetrahydrofuran ether glycol, 5 g of D2000 and 10 g of T5000, stir for 15 min, slowly add 0.5 g of imidazole salt accelerator, add 1.5 g of non-removal aid after stirring for 0.5 h, and continue to stir for 0.5 h to obtain curing agent mixture B;

[0045] S3. Mix the epoxy resin mixture A prepared in S1 and the curing agent mixture B prepared in S2 at a mass ratio of 100:105, stir evenly, and then remove the bubbles by vacuum degassing to obtain an epoxy resin composition.

[0046] Example 4

[0047] S1. At 60 °C, 20 g of E-51, 20 g of E-54 and 20 g of F-51 were stirred at a speed of 50 rpm until the viscosity was lower than 1000 mPa·s. Then, 2 g of polyethylene glycol diglycidyl ether, 2 g of glycerol triglycidyl ether, 2 g of phenyl glycidyl ether, 12 g of sea-island structure toughening agent, and 1.5 g of coupling agent were added, and stirring was continued for 1 h to obtain epoxy resin mixture A;

[0048] S2. At 80 °C, 60 g of methyltetrahydrophthalic anhydride was stirred at 30 rpm. Then, 8 g of polytetrahydrofuran ether diol and 10 g of T5000 were added. After stirring for 15 min, 0.5 g of quaternary ammonium salt, 0.5 g of imidazole, and 0.5 g of imidazole salt accelerator were slowly added. After stirring for 0.5 h, 1.2 g of non-removal aid was added, and stirring was continued for 0.5 h to obtain curing agent mixture B;

[0049] S3. The epoxy resin mixture A prepared in S1 and the curing agent mixture B prepared in S2 were mixed at a mass ratio of 100:115 and stirred evenly. Then, air bubbles were removed by vacuum degassing to obtain an epoxy resin composition.

[0050] Example 5

[0051] S1. At 60 °C, 80 g of F-51 was stirred at a speed of 50 rpm until the viscosity was lower than 1000 mPa·s. Then, 2 g of polyethylene glycol diglycidyl ether, 8 g of sea-island structure toughening agent, 1 g of defoaming agent, and 1 g of wetting agent were added, and stirring was continued for 1 h to obtain epoxy resin mixture A;

[0052] S2. At 80 °C, 70 g of methylhexahydrophthalic anhydride was stirred at 30 rpm. Then, 5 g of polytetrahydrofuran ether diol and 9 g of D2000 were added. After stirring for 15 min, 1 g of quaternary ammonium salt and 1.5 g of imidazole accelerator were slowly added. After stirring for 0.5 h, 1.8 g of non-removal aid was added, and stirring was continued for 0.5 h to obtain curing agent mixture B;

[0053] S3. The epoxy resin mixture A prepared in S1 and the curing agent mixture B prepared in S2 were mixed at a mass ratio of 100:100 and stirred evenly. Then, air bubbles were removed by vacuum degassing to obtain an epoxy resin composition.

[0054] Comparative Example 1

[0055] Compared with Example 1, 10 g of nitrile rubber was used in step S1, and the remaining steps were the same.

[0056] Comparative Example 2

[0057] Compared with Example 1, the non-stripping aid in Step S2 was replaced with an internal demolding agent, and the remaining steps were the same.

[0058] The epoxy resin compositions prepared in Examples 1-5 and Comparative Examples 1-2 were poured into a spline mold for curing to obtain cast body splines, and then the tensile properties and impact properties were tested according to ISO527-2.2019 and ISO 179-1 respectively. The test results are shown in Table 1.

[0059]

[0060]

[0061] Table 1 Test Results of the Performance of Cast Body Splines

[0062] As can be seen from Table 1, since the only difference between Comparative Example 1 and Example 1 lies in the toughening agent in the epoxy resin mixture A, it is shown that using a sea-island structure toughening agent in Example 1 can enable the cast body spline to have good and balanced toughness and impact resistance, while Comparative Example 1 can only improve the impact resistance of the cast body spline, but is lacking in toughness compared to Example 1.

[0063] For Comparative Example 2, the only difference from Example 1 is that the non-stripping aid is replaced with an internal demolding agent, but the internal demolding agent has no effect on the performance of the cast body spline. Therefore, there will be no significant difference in the performance between Example 1 and Comparative Example 2.

[0064] Applications of Example 1 and Comparative Example 2 in pultruded plates:

[0065] 1. Example 1 was combined with TMⅡ fiber, and pultruded plates were made at pultrusion speeds of 60, 70, and 80 cm / min respectively.

[0066] 2. Example 1 was combined with TMⅢ fiber, and a pultruded plate was made at a pultrusion speed of 80 cm / min.

[0067] 3. Comparative Example 2 was combined with TMⅡ fiber, and a pultruded plate was made at a pultrusion speed of 80 cm / min.

[0068] The pultruded plates prepared above were subjected to performance testing according to the testing methods shown in Table 2, and the measured performance results are shown in Table 3.

[0069]

[0070]

[0071] Table 2 Testing Methods for the Performance of Pultruded Plates

[0072]

[0073]

[0074] Table 3 Performance test results of each pultruded plate

[0075] As can be seen from Table 3, in Example 1 with TMⅡ fibers, at different pultrusion speeds of 60, 70, and 80 cm / min, the properties of the pultruded plates prepared are maintained well and can meet the performance indicators of the industry, indicating that the use of the internal release aid in the present invention can ensure that the pultruded plates still have good properties under the conditions of removing the internal release cloth, removing the internal release agent, and high-speed pultrusion; while in Example 1 with TMⅢ fibers, since the mechanical properties and modulus of TMⅢ fibers are significantly improved compared with TMⅡ fibers, therefore, also at a pultrusion speed of 80 cm / min, the properties of the pultruded plates prepared are also significantly improved.

[0076] For the pultruded plate prepared in Comparative Example 2, although its properties can also meet the performance standards of the industry, due to the internal release agent added, it is necessary to use an internal release cloth during pultrusion, which not only increases the production cost but also brings additional process complexity, and at a pultrusion speed of 80 cm / min, smoke is generated when the pultruded plate exits the mold.

[0077] In summary, the epoxy resin composition prepared by the present invention can balance good process performance and mechanical properties under high-speed pultrusion conditions, and can not only be used to prepare pultruded plates, but also can be used to prepare various pultruded profiles, having a wide range of application prospects.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. An epoxy resin composition, characterized in that It comprises an epoxy resin mixture A and a curing agent mixture B, wherein the mass ratio of the epoxy resin mixture A to the curing agent mixture B is 100:85-115; Wherein, the epoxy resin mixture A comprises, by weight: 50 to 90 parts of epoxy resin, 0 to 10 parts of diluent, 5 to 20 parts of toughening agent and 0.1 to 3 parts of auxiliary agent; Calculated by weight, the curing agent mixture B includes: 50-90 parts of anhydride curing agent, 10-30 parts of a toughening agent, 0.5-3 parts of an accelerator, and 1-2 parts of a stripping-free aid.

2. An epoxy resin composition according to claim 1, characterized in that: The mass ratio of the diluent to the toughening agent in the epoxy resin mixture A is 0-10:5-20.

3. An epoxy resin composition according to claim 1, characterized in that: The epoxy resin is at least one of bisphenol A epoxy resin and bisphenol F epoxy resin; The diluent is one or more of polyethylene glycol glycidyl ether, glycerol triglycidyl ether and phenyl glycidyl ether; The toughening agent in the epoxy resin mixture A is an island structure toughening agent; The auxiliary agent is one or more of a coupling agent, a defoaming agent and a wetting agent.

4. An epoxy resin composition according to claim 1, characterized in that: The acid anhydride curing agent is at least one of methyltetrahydrophthalic anhydride and methylhexahydrophthalic anhydride; The toughening agent in the curing agent mixture B is composed of polyether polyol and polyether amine in a mass ratio of 3-11:7-17; The accelerator is one or more of quaternary ammonium salts, imidazoles and imidazole salts.

5. An epoxy resin composition according to claim 3, characterized in that: The epoxy resin is one or more of E-51, E-54 and F-51.

6. An epoxy resin composition according to claim 4, characterized in that: The mass ratio of the polyether polyol to the polyether amine is 5-10:8-15.

7. An epoxy resin composition according to claim 4, characterized in that: The polyether polyol is polytetramethylene ether diol, and the polyether amine is one of D2000 and T5000.

8. An epoxy resin composition according to claim 1, characterized in that: The main structural formula of the free-removal aid is:

9. The method for preparing an epoxy resin composition according to claim 1, characterized in that: The following steps are involved: S1. Take epoxy resin, diluent, toughening agent and additives, mix well to obtain epoxy resin mixture A; S2. Take anhydride curing agent, toughening agent, accelerator and free-release agent, mix well to obtain curing agent mixture B; S3. The epoxy resin mixture A prepared in S1 and the curing agent mixture B prepared in S2 are mixed and cured in a mass ratio of 100:85 to 115 to obtain an epoxy resin composition.

10. Use of the epoxy resin composition according to any one of claims 1 to 8 in pultruded boards.

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