An epoxy resin composition, a method for preparing the same, and an application thereof

Abstract

This invention relates to an epoxy resin composition, its preparation method, and its applications. The epoxy resin composition comprises, by weight, the following components: 35-80 parts by weight of liquid epoxy resin, 30-70 parts by weight of solid resin, 20-50 parts by weight of phenolic curing agent, and 1-8 parts by weight of latent curing agent; the solid resin includes solid epoxy resin; and the phenolic curing agent has a softening point of 60-90°C. The epoxy resin composition provided by this invention, through the screening and compounding of its components, exhibits good flame retardant properties, excellent mechanical properties, and a long storage time.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to an epoxy resin composition, its preparation method, and its application. Background Technology

[0002] Currently, hot-melt flame-retardant epoxy resin prepregs are generally divided into two types: halogenated and halogen-free. Halogenated flame-retardant epoxy resin prepregs typically use bromine-containing epoxy resins, offering higher flame-retardant efficiency and better mechanical properties. However, these prepregs usually produce a large amount of smoke during combustion, making them unsuitable for applications with high smoke density requirements, such as the rail transportation sector. Their use is also restricted in products with halogen content requirements. Halogen-free flame-retardant epoxy resin prepregs generally require the addition of large amounts of inorganic or organic additive flame retardants to meet the requirements of EN45545, FAR25.853, and UL94V0. However, their mechanical properties deteriorate due to the addition of these additive flame retardants.

[0003] CN114302907A provides a resin composition comprising an epoxy resin, a curing agent, and an inorganic filler; the inorganic filler includes: silica-treated magnesium hydroxide, wherein the silica-treated magnesium hydroxide is magnesium hydroxide with a silica surface treated; and aluminum hydroxide. Although the resin composition achieves good flame retardant properties due to the addition of the inorganic filler, its mechanical properties cannot be guaranteed.

[0004] Epoxy resin prepregs have wide applications in the composite materials industry. Preparation methods include hot-melt and solvent methods, with the hot-melt method being the most common. Phenolic curing agents have good flame retardancy, but generally have high softening points. When preparing prepregs using the hot-melt method, the phenolic curing agent and epoxy resin are usually mixed at high temperatures, making them prone to reaction. This shortens the system's shelf life at room temperature, causing the prepreg to lose its tackiness within a short time. Therefore, ensuring a longer shelf life for the prepreg while still utilizing phenolic curing agents in prepregs is a pressing issue that needs to be addressed.

[0005] Since existing halogen-free flame-retardant epoxy resin prepregs generally suffer from poor mechanical properties due to the use of additive flame retardants, and the use of phenolic curing agents results in a shorter shelf life, it is imperative to design an epoxy resin composition containing phenolic curing agents that has good flame retardant properties, excellent mechanical properties, and a long shelf life. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention aims to provide an epoxy resin composition, its preparation method and application, wherein the epoxy resin composition, through the screening and compounding of its various components, has the characteristics of good flame retardancy, excellent mechanical properties and long storage time.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an epoxy resin composition, wherein the epoxy resin composition comprises, by weight, the following components:

[0009]

[0010] The solid resin includes solid epoxy resin; the softening point of the phenolic curing agent is 60-90℃.

[0011] The epoxy resin composition provided by this invention, through the compounding of various components, gives the epoxy resin composition good flame retardant properties and mechanical properties. In addition, by limiting the softening point of the phenolic curing agent, the epoxy resin composition has a long storage time.

[0012] The liquid epoxy resin in the epoxy resin composition is 35-80 parts by weight, for example, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight or 80 parts by weight, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0013] In this invention, the amount of liquid epoxy resin used needs to be controlled within a suitable range. If the amount is too small, the epoxy resin composition will be too dry at room temperature, which is not conducive to impregnation. Furthermore, the prepreg is required to be soft and viscous at room temperature. If the epoxy resin composition is too dry, it will not be conducive to operation at room temperature. If the amount of liquid epoxy resin used is too large, the viscosity of the epoxy resin composition will be too low, and the proportion of flame retardant components will decrease, which will worsen the flame retardant performance of the epoxy resin composition.

[0014] The solid resin is 30-70 parts by weight, for example, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight or 70 parts by weight, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0015] The phenolic curing agent is 20-50 parts by weight, for example, 20 parts by weight, 22 parts by weight, 25 parts by weight, 28 parts by weight, 30 parts by weight, 32 parts by weight, 35 parts by weight, 38 parts by weight, 40 parts by weight, 42 parts by weight, 45 parts by weight, 48 parts by weight or 50 parts by weight, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0016] The latent curing agent is 1-8 parts by weight, for example, it can be 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight, etc., and specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0017] The softening point of the phenolic curing agent is 60-90℃, for example, it can be 60℃, 62℃, 65℃, 68℃, 70℃, 75℃, 80℃, 85℃, 88℃ or 90℃, as well as specific point values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific point values ​​included in the range.

[0018] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0019] As a preferred technical solution, the viscosity of the epoxy resin composition at 70°C is 12000-24000 cPs, for example, it can be 13000 cPs, 14000 cPs, 15000 cPs, 16000 cPs, 17000 cPs, 18000 cPs, 19000 cPs, 20000 cPs, 21000 cPs, 22000 cPs, 23000 cPs, etc.

[0020] Preferably, the liquid epoxy resin includes liquid bisphenol A type epoxy resin and / or liquid bisphenol F type epoxy resin.

[0021] Preferably, the epoxy equivalent of the liquid epoxy resin is 150-210, for example, it can be 155, 160, 165, 170, 175, 180, 185, 190, 195, 200 or 205, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0022] Preferably, the solid epoxy resin includes any one or a combination of at least two of solid bisphenol A type epoxy resin, DOPO epoxy resin, or phenolic epoxy resin.

[0023] In this invention, the DOPO epoxy resin can be obtained through existing technology. For example, the DOPO epoxy resin can be selected from YEP-570 of Guangdong Guangshan New Material Co., Ltd.

[0024] Preferably, the epoxy equivalent of the solid epoxy resin is 250-2500, for example, it can be 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, etc.

[0025] Preferably, the solid resin further includes a thermoplastic resin.

[0026] Preferably, the thermoplastic resin includes any one or a combination of at least two of phenoxy resin, polysulfone, polyamide-imide, or polyetheretherketone.

[0027] Preferably, the weight-average molecular weight of the phenoxy resin is 50,000-80,000, for example, it can be 52,000, 54,000, 56,000, 58,000, 60,000, 62,000, 64,000, 66,000, 68,000, 70,000, 72,000, 74,000, 76,000, 78,000, etc.

[0028] Preferably, the mass percentage of thermoplastic resin in the solid resin is 1-6%, for example, it can be 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, etc.

[0029] Preferably, the phenolic curing agent includes any one or a combination of at least two of phenol-formaldehyde type phenolic resin, o-cresol phenolic resin, XYLOK phenolic resin, or trifunctional phenolic resin.

[0030] In this invention, the phenolic curing agent can be obtained through existing technology. For example, the phenol-formaldehyde type phenolic resin can be selected from PFNH9080L of Hunan Jiashengde Materials Technology Co., Ltd.; the o-cresol phenolic resin can be selected from PFNH9880L of Hunan Jiashengde Materials Technology Co., Ltd.; the XYLOK phenolic resin can be selected from PNH9780L of Hunan Jiashengde Materials Technology Co., Ltd.; and the trifunctional phenolic resin can be selected from TPNH9750L of Hunan Jiashengde Materials Technology Co., Ltd.

[0031] Preferably, the latent curing agent includes a dicyandiamide curing agent.

[0032] Preferably, the epoxy resin composition further includes 1-10 parts by weight of an accelerator, for example, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight or 10 parts by weight, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0033] Preferably, the accelerator includes modified urea accelerators, such as any one or a combination of at least two of dichlorophenyldimethylurea, phenyldimethylurea, toluene dimethylurea, p-chlorophenyldimethylurea, 1,1-dimethyl-3-(3-trifluoromethylphenyl)urea or methylene diphenyldimethylurea.

[0034] Preferably, the epoxy resin composition further includes 0.2-1 parts by weight of defoamer, for example, 0.25 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight, 0.7 parts by weight, 0.75 parts by weight, 0.8 parts by weight, 0.85 parts by weight, 0.9 parts by weight, 0.95 parts by weight, etc.

[0035] Preferably, the defoamer includes silicone-based defoamers and / or silicone-free defoamers.

[0036] In a second aspect, the present invention provides a method for preparing the epoxy resin composition as described in the first aspect, the method comprising:

[0037] The liquid epoxy resin, solid resin, phenolic curing agent, and latent curing agent are mixed evenly to obtain the epoxy resin composition.

[0038] Preferably, the mixed materials further include accelerators and / or defoamers.

[0039] Preferably, the mixing method includes the following steps:

[0040] (1) The solid resin is divided into two parts, and the liquid epoxy resin is divided into two parts; the first part of liquid epoxy resin and the first part of solid resin are mixed for the first time to obtain a first mixture; the first mixture is mixed with the second part of solid resin for the second time to obtain an epoxy resin intermediate.

[0041] The second liquid epoxy resin, the latent curing agent, the accelerator, and the defoamer are mixed in a third mixture to obtain a curing agent slurry;

[0042] (2) The epoxy resin intermediate and the phenolic curing agent are mixed in a fourth mixture to obtain a second mixture; the second mixture is mixed in a fifth mixture with the curing agent slurry to obtain the epoxy resin composition.

[0043] The method for preparing the epoxy resin composition provided by this invention belongs to the hot-melt method. The solid resin is divided into two parts, which can be done either by weight or by type (when there is more than one type of solid resin). For example, when divided by weight, the two parts are of the same type, and their masses may be the same or different; when divided by type, the two parts are of different types, and their masses may be the same or different.

[0044] The liquid epoxy resin is divided into two portions, either by weight or by type (when there is more than one type of liquid epoxy resin). For example, when divided by weight, the two portions will be of the same type, and their masses may be the same or different; when divided by type, the two portions will be of different types, and their masses may be the same or different.

[0045] Preferably, the mass ratio of the first part of solid resin to the second part of solid resin is 1:(4-50), for example, it can be 1:6, 1:8, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45 or 1:50, etc.

[0046] Preferably, the mass ratio of the first part of liquid epoxy resin to the second part of liquid epoxy resin is (2-10):1, for example, it can be 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, etc.

[0047] Preferably, the temperature of the first mixing is 120-160°C, for example, it can be 125°C, 130°C, 135°C, 140°C, 145°C, 150°C or 155°C, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0048] Preferably, the first mixing time is 1-4 hours, for example, it can be 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific point values ​​included in the range.

[0049] Preferably, the temperature of the second mixing is 110-140℃, for example, it can be 110℃, 112℃, 115℃, 120℃, 121℃, 122℃, 123℃, 124℃, 125℃, 126℃, 127℃, 128℃, 129℃, 130℃, 135℃ or 140℃, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0050] Preferably, the second mixing time is 1-4 hours, for example, it can be 1 hour, 1.2 hours, 1.5 hours, 1.8 hours, 2 hours, 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours or 4 hours, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0051] Preferably, the viscosity of the epoxy resin intermediate at 70°C is 4000-9000 cPs, for example, it can be 4500 cPs, 5000 cPs, 5500 cPs, 6000 cPs, 6500 cPs, 7000 cPs, 7500 cPs, 8000 cPs, 8500 cPs, etc.

[0052] Preferably, the temperature of the third mixing is 20-40℃, for example, it can be 22℃, 24℃, 26℃, 28℃, 30℃, 32℃, 34℃, 36℃, 38℃, etc.

[0053] Preferably, the viscosity of the curing agent slurry at 50°C is 1400-3500 cPs, for example, it can be 1500 cPs, 1600 cPs, 1800 cPs, 2000 cPs, 2200 cPs, 2400 cPs, 2600 cPs, 2800 cPs, 3000 cPs, 3200 cPs, 3400 cPs, etc.

[0054] Preferably, the temperature of the fourth mixing is 70-90℃, for example, it can be 70℃, 72℃, 74℃, 76℃, 78℃, 80℃, 82℃, 84℃, 86℃, 88℃ or 90℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0055] Preferably, the fourth mixing time is 1-2 hours, for example, it can be 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours or 2 hours, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0056] Preferably, the temperature of the fifth mixing is 50-80℃, for example, it can be 50℃, 52℃, 55℃, 58℃, 60℃, 62℃, 65℃, 68℃, 70℃, 72℃, 75℃ or 78℃, as well as specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0057] Preferably, the fifth mixing time is 5-20 min, for example, it can be 5 min, 6 min, 7 min, 8 min, 10 min, 12 min, 14 min, 16 min, 18 min or 20 min, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific point values ​​included in the range.

[0058] Thirdly, the present invention provides a prepreg comprising a reinforcing material and an epoxy resin composition as described in the first aspect, which is attached thereto after impregnation and drying.

[0059] Preferably, the reinforcing material includes any one of carbon fiber, glass fiber, aramid fiber, or basalt fiber.

[0060] Fourthly, the present invention provides a laminate comprising at least one prepreg as described in the third aspect.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] The epoxy resin composition provided by this invention, through the screening and compounding of its various components, possesses excellent flame retardant properties, superior mechanical properties, and a long shelf life. Prepregs prepared using the epoxy resin composition provided by this invention exhibit tensile strength of 66-78 MPa, tensile modulus of 3120-3300 MPa, elongation at break of 2.8-3.5%, flexural strength of 125-140 MPa, flexural modulus of 3000-3200 MPa, and impact strength of 20-30 kJ / m². 2 The epoxy resin composition provided by this invention has a storage time of 22-28 days at room temperature and a glass transition temperature of 115-126℃. Laminates prepared using the epoxy resin composition provided by this invention exhibit good flame retardancy. Detailed Implementation

[0063] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0064] The sources of some components in the examples and comparative examples are as follows:

[0065] (1) Liquid epoxy resin:

[0066] a. Liquid bisphenol A type epoxy resin: NPEL-128 purchased from Kunshan Nanya, with an epoxy equivalent of 186;

[0067] b. Liquid bisphenol F type epoxy resin: NPEF-170 purchased from Kunshan Nanya, with an epoxy equivalent of 170;

[0068] (2) Solid resin:

[0069] a. DOPO epoxy resin: YEP-570 purchased from Guangshan, Guangdong, with an epoxy equivalent of 310;

[0070] b. Solid bisphenol A type epoxy resin: Kunshan Nanya's NPES-601, with an epoxy equivalent of 455; Kunshan Nanya's NPES-609, with an epoxy equivalent of 2500;

[0071] c. Phenoxy resin: YP-50H purchased from Gabriel, USA, with a weight-average molecular weight of 52,000;

[0072] (3) Dicyandiamide curing agent: ECURE 20 purchased from Shanghai Moman Chemical Co., Ltd.;

[0073] (4) Accelerators: DYHARD UR200, DYHARD UR300 and DYHARD UR500 were purchased from Shanghai Moman Chemical Co., Ltd.

[0074] (5) o-cresol formaldehyde resin:

[0075] a. PFNH9880L, purchased from Hunan Jiashengde Materials Technology Co., Ltd., has a softening point of 75-85℃;

[0076] b. PFNH9880M, purchased from Hunan Jiashengde Materials Technology Co., Ltd., has a softening point of 95-105℃;

[0077] (6) XYLOK phenolic resin: PNH9780L purchased from Hunan Jiashengde Materials Technology Co., Ltd., with a softening point of 70-75℃;

[0078] (7) Phenolic resin of formaldehyde type: PFNH9080L purchased from Hunan Jiashengde Materials Technology Co., Ltd., with a softening point of 75-85℃.

[0079] (8) Defoamer: BYKA-530 purchased from BYK Chemicals;

[0080] (9) Carbon fiber woven fabric: purchased from Zhongfu Shenying 24K T300, with a thickness of about 0.4mm.

[0081] In the following examples and comparative examples, the viscosity and gel time of the corresponding substances in the examples and comparative examples were tested according to the following methods:

[0082] (1) Viscosity: Tested using a Bollerfeld CAP2000+ cone-plate viscometer;

[0083] (2) Gel time: The gel time is measured by using the CT-2 gelation time tester produced by Lin'an Fengyuan.

[0084] Example 1

[0085] An epoxy resin composition comprising, by weight, the following components:

[0086]

[0087]

[0088] The preparation method of the epoxy resin composition includes the following steps:

[0089] (1) Take 50 parts by weight of liquid bisphenol A type epoxy resin NPEL-128 and phenoxy resin YP-50H and mix them. Stir at 140℃ for 1.5h. After the phenoxy resin YP-50H is completely dissolved, the first mixture is obtained.

[0090] The first mixture, DOPO epoxy resin YEP-570, and solid bisphenol A epoxy resin NPES-601 were stirred at 120°C for 1 hour until completely dissolved, filtered, and placed in a container to obtain an epoxy resin intermediate; the viscosity of the epoxy resin intermediate at 70°C was 6300 cPs.

[0091] At room temperature, the remaining liquid bisphenol A epoxy resin NPEL-128, dicyandiamide curing agent ECURE 20, accelerator DYHARD UR200 and defoamer BYKA-530 are stirred evenly in a planetary mixer and then passed through a three-roll mill to prepare a curing agent slurry for later use. The viscosity of the curing agent slurry at 50°C is 2200 cPs.

[0092] (2) Heat the epoxy resin intermediate to 78°C, add o-cresol resin PFNH9880L, and stir in a planetary mixer for 1.5 h until the o-cresol resin PFNH9880L is completely dissolved to obtain a second mixture.

[0093] The second mixture is mixed with the curing agent slurry at room temperature, and stirred at 70°C for 10 min to obtain the epoxy resin composition. The mixture is then poured out and stored in a -18°C cold storage. The epoxy resin composition has a viscosity of 14500 cPs at 70°C and a gel time of 580 s at 120°C.

[0094] A prepreg and laminate comprising the epoxy resin composition, wherein the preparation method is as follows:

[0095] The epoxy resin composition was impregnated with Zhongfu Shenying 24K T300 carbon fiber woven fabric at 65°C, and the resin content was controlled to be 38% to obtain the prepreg.

[0096] Five sheets of the prepreg are stacked together with a layer thickness of about 1.9 mm, and cured at 140°C for 1 hour using a hot press to obtain the laminate.

[0097] Example 2

[0098] An epoxy resin composition comprising, by weight, the following components:

[0099]

[0100] The preparation method of the epoxy resin composition includes the following steps:

[0101] (1) Take 45 parts by weight of liquid bisphenol F type epoxy resin NPEF-170 and phenoxy resin YP-50H and stir at 140℃ for 1.5h. After the phenoxy resin YP-50H is completely dissolved, add solid bisphenol A type epoxy resin NPES-609 and stir for 1h until completely dissolved to obtain the first mixture.

[0102] The first mixture, DOPO epoxy resin YEP-570, and solid bisphenol A type epoxy resin NPES-601 were mixed and stirred at 120°C for 1 hour until completely dissolved. The mixture was then filtered and placed into a container to obtain an epoxy resin intermediate. The viscosity of the epoxy resin intermediate at 70°C was 6850 cPs.

[0103] At room temperature, the remaining liquid bisphenol F epoxy resin NPEF-170, dicyandiamide curing agent ECURE20, accelerator DYHARD UR300 and defoamer BYKA-530 are mixed evenly in a planetary mixer and then passed through a three-roll mill to prepare a curing agent slurry for later use. The viscosity of the curing agent slurry at 50°C is 2050 cPs.

[0104] (2) Heat the epoxy resin intermediate to 75°C, add phenol-formaldehyde type phenolic resin PFNH9080L, and stir in a planetary mixer for 1.5 hours until the phenol-formaldehyde type phenolic resin PFNH9080L is completely dissolved to obtain a second mixture.

[0105] The second mixture was mixed with the curing agent slurry at room temperature, and stirred at 72°C for 10 min to obtain the epoxy resin composition. The mixture was then poured out and stored in a -18°C cold storage. The epoxy resin composition had a viscosity of 14900 cPs at 70°C and a gel time of 625 s at 120°C.

[0106] A prepreg and laminate comprising the epoxy resin composition, wherein the preparation method is as follows:

[0107] The epoxy resin composition was impregnated with Zhongfu Shenying 24K T300 carbon fiber woven fabric at 65°C, and the resin content was controlled to be 40% to obtain the prepreg.

[0108] Five sheets of the prepreg are stacked together, with a layer thickness of about 2.2 mm, and cured at 140°C for 1 hour using a hot press to obtain the laminate.

[0109] Example 3

[0110] An epoxy resin composition comprising, by weight, the following components:

[0111]

[0112]

[0113] The preparation method of the epoxy resin composition includes the following steps:

[0114] (1) Take 40 parts by weight of liquid bisphenol A type epoxy resin NPEL-128 and phenoxy resin YP-50H and stir at 140℃ for 1.5h. After the phenoxy resin YP-50H is completely dissolved, add solid bisphenol A type epoxy resin NPES-609 and continue stirring for 2.5h to obtain the first mixture.

[0115] The first mixture, DOPO epoxy resin YEP-570 and solid bisphenol A type epoxy resin NPES-601 were mixed and stirred at 120°C for 1 hour until completely dissolved. The mixture was then filtered and placed in a container to prepare an epoxy resin intermediate. The viscosity of the epoxy resin intermediate at 70°C was 7300 cPs.

[0116] At room temperature, the remaining liquid bisphenol A epoxy resin NPEL-128, dicyandiamide curing agent ECURE 20, accelerator DYHARD UR500 and defoamer BYKA-530 are stirred evenly in a planetary mixer and then passed through a three-roll mill to prepare a curing agent slurry for later use. The viscosity of the curing agent slurry at 50°C is 1450 cPs.

[0117] (2) At 79°C, the epoxy resin intermediate is mixed with XYLOK phenolic resin PNH9780L and stirred in a planetary mixer for 1.5 h until XYLOK phenolic resin PNH9780L is completely dissolved to obtain a second mixture.

[0118] The second mixture was mixed with the curing agent slurry at room temperature, and stirred at 70°C for 10 min to obtain the epoxy resin composition. The mixture was then poured out and stored in a -18°C cold storage. The epoxy resin composition had a viscosity of 15200 cPs at 70°C and a gel time of 646 s at 120°C.

[0119] A prepreg and laminate comprising the epoxy resin composition, wherein the preparation method is as follows:

[0120] The epoxy resin composition was impregnated with Zhongfu Shenying 24K T300 carbon fiber woven fabric at 65°C, and the resin content was controlled to be 42% to obtain the prepreg.

[0121] Five sheets of the prepreg are stacked together with a layer thickness of about 2.0 mm, and cured at 130°C for 2 hours using a hot press to obtain the laminate.

[0122] Example 4

[0123] An epoxy resin composition comprising, by weight, the following components:

[0124]

[0125] The preparation method of the epoxy resin composition includes the following steps:

[0126] (1) Take 37 parts by weight of liquid bisphenol A type epoxy resin NPEL-128 and solid bisphenol A type epoxy resin NPES-609 and stir at 140℃ for 1 hour. After the solid bisphenol A type epoxy resin NPES-609 is completely dissolved, the first mixture is obtained.

[0127] The first mixture was mixed with DOPO epoxy resin YEP-570 and stirred at 120°C for 1 hour until completely dissolved. The mixture was then filtered and placed into a container to prepare an epoxy resin intermediate. The viscosity of the epoxy resin intermediate at 70°C was 8900 cPs.

[0128] At room temperature, the remaining liquid bisphenol A epoxy resin NPEL-128, dicyandiamide curing agent ECURE 20, accelerator DYHARD UR500 and defoamer BYKA-530 are mixed evenly in a planetary mixer and then passed through a three-roll mill to prepare a curing agent slurry for later use. The viscosity of the curing agent slurry at 50°C is 3450 cPs.

[0129] (2) At 77°C, the epoxy resin intermediate is mixed with XYLOK phenolic resin PNH9780L and stirred in a planetary mixer for 1.5 h until XYLOK phenolic resin PNH9780L is completely dissolved to obtain a second mixture.

[0130] The second mixture and the curing agent slurry are mixed and stirred at 72°C for 10 min to obtain the epoxy resin composition. The mixture is then poured out and stored in a -18°C cold storage. The epoxy resin composition has a viscosity of 15800 cPs at 70°C and a gel time of 670 s at 120°C.

[0131] A prepreg and laminate comprising the epoxy resin composition, wherein the preparation method is as follows:

[0132] The epoxy resin composition was impregnated with Zhongfu Shenying 24K T300 carbon fiber woven fabric at 65°C, and the resin content was controlled to be 40% to obtain the prepreg.

[0133] Five sheets of the prepreg are stacked together with a layer thickness of about 1.9 mm, and cured at 135°C for 1.5 h using a hot press to obtain the laminate.

[0134] Comparative Example 1

[0135] An epoxy resin composition and its preparation method are disclosed, differing from Example 1 in that an equal mass of o-cresol formaldehyde resin PFNH9880L is replaced with o-cresol formaldehyde resin PFNH9880M, and the preparation method of the epoxy resin composition is as follows:

[0136] (1) Take 50 parts by weight of liquid bisphenol A type epoxy resin NPEL-128 and phenoxy resin YP-50H and stir at 140℃ for 1.5h. After the phenoxy resin YP-50H is completely dissolved, cool down to 120℃, add DOPO epoxy resin YEP-570 and solid bisphenol A type epoxy resin NPES-601, stir for 1h until completely dissolved, add o-cresol formaldehyde resin PFNH9880M, stir at 120℃ in a planetary mixer for 1.5h until the o-cresol formaldehyde resin PFNH9880M is completely dissolved, filter and put into a container to make an epoxy resin intermediate with a viscosity of 23300cPs at 70℃.

[0137] At room temperature, the remaining liquid bisphenol A epoxy resin NPEL-128, dicyandiamide curing agent ECURE 20, accelerator DYHARD UR200 and defoamer BYKA-530 are mixed evenly in a planetary mixer and then passed through a three-roll mill to make a curing agent slurry for later use. Its viscosity at 50°C is 2200 cPs.

[0138] (2) The epoxy resin intermediate is heated to 70°C, and then the curing agent slurry at room temperature is added. After stirring for 10 minutes, the epoxy resin composition is obtained, poured out and stored in a -18°C cold storage. The epoxy resin composition has a viscosity of 15400 cPs at 70°C and a gel time of 620s at 120°C.

[0139] A prepreg and laminate comprising the epoxy resin composition, prepared in the same manner as in Example 1.

[0140] Comparative Example 2

[0141] An epoxy resin composition comprising, by weight, the following components:

[0142]

[0143] (1) Take 40 parts by weight of liquid bisphenol A type epoxy resin NPEL-128 and phenoxy resin YP-50H and stir at 140℃ for 1.5h. After the phenoxy resin YP-50H is completely dissolved, the first mixture is obtained.

[0144] The first mixture was mixed with solid bisphenol A type epoxy resin NPES-601 and stirred at 120°C for 1 hour until completely dissolved. Then, DOPO epoxy resin YEP-570 was added and stirred for 1 hour until completely dissolved. Aluminum hydroxide and magnesium hydroxide were added, stirred evenly, filtered, and placed in a container to prepare an epoxy resin intermediate with a viscosity of 42200 cPs at 70°C.

[0145] At room temperature, the remaining liquid bisphenol A epoxy resin NPEL-128, dicyandiamide curing agent ECURE 20, accelerator DYHARD UR200 and defoamer BYKA-530 are mixed evenly in a planetary mixer and then passed through a three-roll mill to make a curing agent slurry for later use. The viscosity at 50°C is 2050 cPs.

[0146] (2) Heat the epoxy resin intermediate to 85°C, then add the curing agent slurry at room temperature, stir for 10 minutes to obtain the epoxy resin composition, pour it out and store it in a -18°C cold storage; the epoxy resin composition has a viscosity of 25760 cPs at 70°C and a gel time of 826s at 120°C.

[0147] A prepreg and laminate comprising the epoxy resin composition, prepared in the same manner as in Example 1.

[0148] Performance testing

[0149] (1) Tensile strength: Tested in accordance with GB / T 2567;

[0150] (2) Tensile modulus: Tested in accordance with GB / T 2567;

[0151] (3) Elongation at break: Tested according to GB / T 2567;

[0152] (4) Bending strength: Tested in accordance with GB / T 2567;

[0153] (5) Flexural modulus: Tested in accordance with GB / T 2567;

[0154] (6) Impact strength: Tested in accordance with GB / T 2567;

[0155] (7) Storage time: Store at room temperature (25℃). Use a Bollerfei CAP2000+ cone-plate viscometer to test the viscosity. The time it takes for the viscosity to double is the storage time.

[0156] (8) Tg: Tested according to ASTM E1640;

[0157] (9) Flame retardancy test: Tested in accordance with UL94, EN45545-2, and FAR25.853;

[0158] The prepregs provided in Examples 1-4 and Comparative Examples 1-2 were tested according to (1)-(6) above. The epoxy resin compositions provided in Examples 1-4 and Comparative Examples 1-2 were tested according to (7)-(8) above. The test results are shown in Table 1. The laminates provided in Examples 1-4 and Comparative Examples 1-2 were tested according to (9). The test results are shown in Table 2.

[0159] Table 1

[0160]

[0161]

[0162] As can be seen from the data in Table 1, the epoxy resin compositions provided in Examples 1-4 have a long storage time, and the prepregs prepared using the epoxy resin compositions provided in Examples 1-4 have good mechanical properties.

[0163] Comparative Example 1 used a phenolic curing agent with a high softening point, resulting in excessively high process temperatures during production. This led to a greater reaction between the phenolic curing agent and the epoxy resin, significantly shortening the storage time of the epoxy resin composition. Comparative Example 2 used a large amount of inorganic fillers, which deteriorated the mechanical properties of the prepreg, significantly reducing its strength and impact toughness.

[0164] Table 2

[0165]

[0166] As can be seen from the data in Table 2, the laminate made using the epoxy resin composition provided by the present invention has good flame retardancy.

[0167] The applicant declares that the epoxy resin composition, its preparation method, and its application are illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A prepreg, characterized in that, The prepreg includes a reinforcing material and an epoxy resin composition that is attached thereto after impregnation and drying; The epoxy resin composition comprises the following components in parts by weight: 35-80 parts by weight of liquid epoxy resin 30-70 parts by weight of solid resin 20-50 parts by weight of phenolic curing agent Latent curing agent, 1-8 parts by weight; The solid resin includes solid epoxy resin; the softening point of the phenolic curing agent is 60-90℃; The viscosity of the epoxy resin composition at 70°C is 12000-24000 cPs. The latent curing agent is a dicyandiamide curing agent; The epoxy resin composition is prepared by the following method, the method comprising: The liquid epoxy resin, solid resin, phenolic curing agent and latent curing agent are mixed evenly to obtain the epoxy resin composition. The mixing method includes the following steps: (1) Divide the solid resin into two parts and the liquid epoxy resin into two parts; mix the first part of liquid epoxy resin and the first part of solid resin to obtain a first mixture; The first mixture is mixed with the second part of solid resin to obtain an epoxy resin intermediate. The second liquid epoxy resin, the latent curing agent, an optional accelerator, and an optional defoamer are mixed in a third mixture to obtain a curing agent slurry; (2) The epoxy resin intermediate and the phenolic curing agent are mixed for a fourth time to obtain a second mixture; The second mixture is mixed with the curing agent slurry in a fifth mixing process to obtain the epoxy resin composition; The viscosity of the epoxy resin intermediate at 70°C is 4000-9000 cPs. The viscosity of the curing agent slurry at 50°C is 1400-3500 cPs.

2. The prepreg according to claim 1, characterized in that, The liquid epoxy resin includes liquid bisphenol A type epoxy resin and / or liquid bisphenol F type epoxy resin.

3. The prepreg according to claim 1, characterized in that, The epoxy equivalent of the liquid epoxy resin is 150-210.

4. The prepreg according to claim 1, characterized in that, The solid epoxy resin includes any one or a combination of at least two of solid bisphenol A type epoxy resin, DOPO epoxy resin, or phenolic epoxy resin.

5. The prepreg according to claim 1, characterized in that, The epoxy equivalent of the solid epoxy resin is 250-2500.

6. The prepreg according to claim 1, characterized in that, The solid resin also includes thermoplastic resin.

7. The prepreg according to claim 6, characterized in that, The thermoplastic resin includes any one or a combination of at least two of phenoxy resin, polysulfone, polyamide-imide, or polyetheretherketone.

8. The prepreg according to claim 6, characterized in that, The mass percentage of thermoplastic resin in the solid resin is 1-6%.

9. The prepreg according to claim 1, characterized in that, The phenolic curing agent includes any one or a combination of at least two of the following: phenol-formaldehyde type phenolic resin, o-cresol phenolic resin, XYLOK phenolic resin, or trifunctional phenolic resin.

10. The prepreg according to claim 1, characterized in that, The epoxy resin composition further includes 1-10 parts by weight of an accelerator.

11. The prepreg according to claim 10, characterized in that, The accelerator includes any one or a combination of at least two of dichlorophenyldimethylurea, phenyldimethylurea, toluene dimethylurea, p-chlorophenyldimethylurea, 1,1-dimethyl-3-(3-trifluoromethylphenyl)urea or methylene diphenyldimethylurea.

12. The prepreg according to claim 1, characterized in that, The epoxy resin composition further includes 0.2-1 parts by weight of defoamer.

13. The prepreg according to claim 12, characterized in that, The defoamer includes silicone-based defoamers and / or silicone-free defoamers.

14. The prepreg according to claim 1, characterized in that, The mixed materials also include accelerators and / or defoamers.

15. The prepreg according to claim 1, characterized in that, The mass ratio of the first part of solid resin to the second part of solid resin is 1:(4-50).

16. The prepreg according to claim 1, characterized in that, The mass ratio of the first part of liquid epoxy resin to the second part of liquid epoxy resin is (2-10):

1.

17. The prepreg according to claim 1, characterized in that, The temperature of the first mixture is 120-160℃.

18. The prepreg according to claim 1, characterized in that, The first mixing time is 1-4 hours.

19. The prepreg according to claim 1, characterized in that, The temperature of the second mixture is 110-140℃.

20. The prepreg according to claim 1, characterized in that, The second mixing time is 1-4 hours.

21. The prepreg according to claim 1, characterized in that, The temperature of the third mixture is 20-40℃.

22. The prepreg according to claim 1, characterized in that, The temperature of the fourth mixture is 70-90℃.

23. The prepreg according to claim 1, characterized in that, The fourth mixing time is 1-2 hours.

24. The prepreg according to claim 1, characterized in that, The temperature of the fifth mixture is 50-80℃.

25. The prepreg according to claim 1, characterized in that, The fifth mixing time is 5-20 minutes.

26. A laminate, characterized in that, The laminate comprises at least one prepreg as described in any one of claims 1-25.

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