High-strength and high-toughness epoxy resin for aviation field and preparation method thereof

Abstract

The invention discloses high-strength and high-toughness epoxy resin for the aviation field. The high-strength and high-toughness epoxy resin comprises the following substances in percentage by mass: 25-35% of carbon fibers, 30-50% of epoxy resin, 0.2-5% of a coupling agent, 6-20% of a curing agent, 0.5-5% of a toughening agent and 0-5% of other auxiliary agents, the toughening agent is mullite whisker. The mullite whiskers and the carbon fibers are added, so that the formed composite material is light in weight and has high strength and high toughness; and the high-thermal-conductivity insulating substrate can be widely applied to secondary force-bearing components in various fields, light-weight components and the fields of electronics and electric appliances.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of epoxy resin, especially to a high-strength and high-toughness resin for aviation field and a preparation method thereof. BACKGROUND

[0002] The resin for aviation field is the matrix material of composite materials, which is widely used in daily life due to its lightweight, high performance and high reliability.

[0003] The resin for aviation field mainly includes epoxy resin EP, bismaleimide resin BMI, polyimide resin PI, cyanate ester resin CE, phenolic resin PF and polyether ether ketone resin PEEK. The epoxy resin EP has high strength, high modulus and excellent adhesion, and is resistant to heat and humidity. Its molding process is mature, but its high temperature resistance is limited. The bismaleimide resin BMI is resistant to high temperature, has high mechanical strength and stable size, and is especially excellent in aging resistance, but its toughness is poor and the curing temperature is high. The polyimide resin PI is resistant to high temperature and chemical corrosion, and has good insulation, but its molding is difficult, the production cost is high and it is relatively brittle. The cyanate ester resin CE has good resistance to heat and humidity, high dimensional accuracy and good anti-creep performance, but its curing time is long and the adhesion is general. The phenolic resin PF has good flame retardance and low cost, but it is brittle and has general heat resistance. The polyether ether ketone resin PEEK is resistant to high temperature and chemical corrosion, has good toughness and can be repeatedly processed, but its cost is extremely high.

[0004] As a widely used thermosetting resin, the epoxy resin is widely used in various fields based on its characteristics and low cost. After curing, the epoxy resin is relatively brittle and has poor toughness, so in use, a certain toughening agent needs to be added. For example, the patent number 202511192614.9, entitled "Preparation method of high-toughness epoxy resin sizing material", adds a modified toughening agent, which is obtained by grafting modification of diisocyanate and alcohol substances in turn, and the toughening agent includes at least one of carboxyl liquid nitrile rubber, hydroxyl liquid butadiene rubber or mercapto liquid nitrile rubber. The prepared high-toughness epoxy resin sizing material has an interpenetrating network structure, and the toughness is improved through the sliding or deformation of flexible segments. SUMMARY

[0005] Based on the above description, the present application aims to provide a high-strength and high-toughness epoxy resin for aviation field and a preparation method thereof. By adding mullite whiskers and carbon fibers, the composite material formed has light weight, high strength and high toughness.

[0006] To achieve the above object, the present application provides the following technical solutions: high-strength and high-toughness epoxy resin for aviation field, comprising the following mass percentage of substances: carbon fiber 25-35%, epoxy resin 30-50%, coupling agent 0.2-5%, curing agent 6-20%, toughening agent 0.5-5%, and other auxiliary agents 0-5%; the toughening agent is mullite whisker.

[0007] Preferably, the epoxy resin is one or more than one of bisphenol A / F modified epoxy resin and nitrogen / silicon-containing epoxy resin.

[0008] Preferably, the curing agent is aromatic amine or acid anhydride.

[0009] Preferably, the other auxiliary agent is one or more than one of release agent, defoaming agent, antioxidant or leveling agent.

[0010] Preferably, the coupling agent is epoxy-based coupling agent KH-560 or amine-based coupling agent KH-550.

[0011] Preferably, the carbon fiber is short carbon fiber, 2-3mm long; the mullite whisker is 300-600μm long.

[0012] The preparation method of the high-strength and high-toughness epoxy resin for aviation field comprises the following steps: S1: surface modification treatment of mullite whisker and carbon fiber by coupling agent, to obtain modified mullite whisker and carbon fiber; S2: mixing of epoxy resin and curing agent, and stirring to disperse uniformly; S3: adding the modified mullite whisker and carbon fiber obtained in S1 into S2, stirring in a high-speed stirrer for 10-15 minutes, at a stirring speed of 2000-3000r / min, to obtain primary premix; ultrasonic dispersion of the primary premix, to obtain premix; S4: adding defoaming agent, antioxidant and release agent into the premix obtained in S3, and mixing uniformly, to obtain slurry; S5: auxiliary setting of the slurry in a required mold, constant temperature and pressure preservation, to obtain the high-strength and high-toughness epoxy resin for aviation field.

[0013] Preferably, the surface modification treatment of mullite whisker and carbon fiber in S1 comprises the following steps: drying of mullite whisker at 120-130℃ for 3 hours and drying of carbon fiber at 110-120℃ for 2 hours, respectively, mixing them in a mixer; dilution of coupling agent with ethanol, atomization and spraying into the mixer, rotation speed of the mixer 1200-1500r / min, stirring at room temperature for 40-50min; drying of the obtained mixture at 90-100℃ for 2-3 hours, to realize the surface modification of mullite whisker and carbon fiber.

[0014] The present application takes epoxy resin as a matrix, adds carbon fiber and mullite whisker, and improves the mechanical properties, heat resistance and wear resistance of the epoxy resin through a synergistic reinforcement mechanism, and the toughness of the epoxy resin is also greatly improved.

[0015] The epoxy resin provides good formability, adhesion and corrosion resistance, the addition of carbon fiber greatly improves the tensile strength, elastic modulus and fatigue resistance of the composite material, and reduces the density of the composite material; the mullite whisker as a secondary reinforcing phase has certain toughness, fills the gap between the carbon fibers, improves the toughness of the composite material, and realizes the heat resistance and wear resistance of the composite material. The surface of the carbon fiber is oxidized by the coupling agent to improve the bonding force with the epoxy resin, and the mullite whisker is coated by the coupling agent to avoid agglomeration and enhance the dispersibility.

[0016] The present application has simple process, and can be widely applied to secondary load-bearing components, lightweight components, high-thermal-conductivity insulating substrates in the field of electronics and electrical appliances. The present application can adjust the proportion of each substance according to actual needs; for example, to improve the mechanical strength, the content of carbon fiber can be increased, and the amount of epoxy resin can be reduced; similarly, to enhance the toughness or heat resistance, the amount of mullite whisker can be increased, and the epoxy resin can be replaced. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. If not particularly stated, the raw materials used are conventional commercial raw materials, and the percentages in the present application are mass percentages.

[0018] Example 1: High-strength and high-toughness epoxy resin for the field of aviation, including the following mass percentage of substances: carbon fiber 30%, epoxy resin 45%, coupling agent 1%, aromatic amine 15%, mullite whisker 5%, antioxidant 1%, defoaming agent 2% and release agent 1%; the epoxy resin is TSPZ-EP epoxy resin; The coupling agent is amine coupling agent KH-550, the carbon fiber is short carbon fiber with a length of 2-3 mm; the mullite whisker is 300-600 μm long; the aromatic amine can be aliphatic aromatic amine and aromatic heterocyclic aromatic amine; the defoaming agent is silicone defoaming agent; the release agent is silicone release agent, and the antioxidant is antioxidant 168.

[0019] The preparation method of the high-strength and high-toughness epoxy resin for the field of aviation, and the preparation steps are as follows: S1: The amine coupling agent KH-550 is used for surface modification treatment of the mullite whisker and the carbon fiber to obtain modified mullite whisker and carbon fiber; S2: The epoxy resin and the aliphatic aromatic amine are mixed and stirred to disperse uniformly; S3: The modified mullite whiskers and carbon fibers are added to S2 and stirred in a high-speed mixer for 10 minutes at a stirring speed of 2000 r / min to obtain a primary premix; the primary premix is dispersed by ultrasonic to obtain a premix; S4: The defoaming agent, antioxidant and release agent are added to the premix obtained in S3 and uniformly mixed to obtain a slurry; S5: The slurry is placed in a required mold, and constant temperature and pressure are maintained to obtain the high-strength and high-toughness epoxy resin for the aviation field. The high-strength and high-toughness epoxy resin for the aviation field obtained has a tensile strength of 458.1 MPa, an elastic modulus of 40.2 GPa and an elongation at break of 1.6%.

[0020] In the process, the mullite whiskers and carbon fibers are subjected to surface modification treatment, and the steps are as follows: the mullite whiskers are dried at 120°C for 3 hours, and the carbon fibers are dried at 110°C for 2 hours, and then they are mixed and placed in a mixer; the coupling agent is diluted with ethanol, and then sprayed into the mixer after atomization; the rotating speed of the mixer is 1200 r / min, and the mixture is stirred at room temperature for 50 minutes; and the obtained mixture is dried at 100°C for 3 hours to realize the surface modification of the mullite whiskers and carbon fibers.

[0021] The high-strength and high-toughness epoxy resin for the aviation field of the embodiment 2 comprises the following substances with mass percentage contents: carbon fibers 25%, epoxy resin 50%, coupling agent 1%, aromatic amine 18%, mullite whiskers 3%, defoaming agent 2% and release agent 1%; the epoxy resin is TSPZ-EP epoxy resin; The coupling agent is amine coupling agent KH-550, the carbon fibers are short carbon fibers with a length of 2-3 mm, the mullite whiskers have a length of 300-600 μm, the aromatic amine can be aliphatic aromatic amine and aromatic heterocyclic aromatic amine, the defoaming agent is silicone defoaming agent, and the release agent is silicone release agent.

[0022] The preparation method of the high-strength and high-toughness epoxy resin for the aviation field comprises the following steps: S1: The mullite whiskers and carbon fibers are subjected to surface modification treatment by amine coupling agent KH-550 to obtain modified mullite whiskers and carbon fibers; S2: The epoxy resin and aliphatic aromatic amine are mixed and uniformly stirred and dispersed; S3: The modified mullite whiskers and carbon fibers of S1 are added to S2 and stirred in a high-speed mixer for 10 minutes at a stirring speed of 2000 r / min to obtain a primary premix; the primary premix is dispersed by ultrasonic to obtain a premix; S4: The defoaming agent and release agent are added to the premix obtained in S3 and uniformly mixed to obtain a slurry; S5: The slurry is placed in a required mold, and constant temperature and pressure are maintained, thereby obtaining the high-strength and high-toughness epoxy resin for the aviation field.

[0023] The mullite whiskers and the carbon fibers are subjected to surface modification treatment, and the steps are as follows: the mullite whiskers are dried at 120 DEG C for 3 hours, and the carbon fibers are dried at 110 DEG C for 2 hours, and then they are mixed and placed in a mixing machine; the coupling agent is diluted with ethanol, and is sprayed into the mixing machine after atomization, the rotating speed of the mixing machine is 1200 r / min, and the mixture is stirred at room temperature for 50 min; the obtained mixture is dried at 100 DEG C for 2-3 hours, thereby realizing the surface modification of the mullite whiskers and the carbon fibers.

[0024] Comparative Example 1: An epoxy resin, comprising the following mass percentage of substances: epoxy resin 80%, coupling agent 1%, aromatic amine 15%, antioxidant 1%, defoaming agent 2% and release agent 1%; the epoxy resin is TSPZ-EP epoxy resin; The coupling agent is amine coupling agent KH-550, the aromatic amine can be aliphatic aromatic amine and aromatic heterocyclic aromatic amine; the defoaming agent is silicone defoaming agent; and the release agent is silicone release agent.

[0025] The preparation method comprises the following steps: The coupling agent, the aliphatic aromatic amine, the antioxidant, the defoaming agent and the release agent are added into the epoxy resin, and are uniformly mixed, thereby obtaining a slurry; the slurry is placed in a required mold, and constant temperature and pressure are maintained, thereby obtaining an epoxy resin. The prepared epoxy resin has a tensile strength of 78.2 MPa, an elastic modulus of 3.1 GPa and a breaking elongation of 2.1%.

[0026] The tensile properties in the examples are tested according to GB / T3356-2014, and the indexes include tensile strength, elastic modulus and breaking elongation, which reflect the tensile load resistance of the composite material.

Claims

1. A high-strength and high-toughness epoxy resin for use in the aerospace field, characterized in that... The substance comprises the following components by weight percentage: 25-35% carbon fiber, 30-50% epoxy resin, 0.2-5% coupling agent, 6-20% curing agent, 0.5-5% toughening agent, and 0-5% other auxiliary agents; the toughening agent is mullite whiskers.

2. The high-strength and high-toughness epoxy resin for the aerospace field according to claim 1, characterized in that... The epoxy resin is one or more of bisphenol A / F modified epoxy resin and nitrogen-containing / silicon epoxy resin.

3. The high-strength and high-toughness epoxy resin for the aerospace field according to claim 1, characterized in that... The curing agent is an aromatic amine or an anhydride.

4. The high-strength and high-toughness epoxy resin for the aerospace field according to claim 1, characterized in that... The other auxiliary agents mentioned are one or more of the following: release agent, defoamer, antioxidant, or leveling agent.

5. The high-strength and high-toughness epoxy resin for the aerospace field according to claim 1, characterized in that... The coupling agent is an epoxy-based coupling agent KH-560 or an amino-based coupling agent KH-550.

6. The high-strength and high-toughness epoxy resin for the aerospace field according to claim 1, characterized in that... The carbon fiber is short-cut carbon fiber, 2-3 mm in length; the mullite whiskers are 300-600 μm in length.

7. The method for preparing a high-strength and high-toughness epoxy resin for the aerospace field as described in any one of claims 1-6, characterized in that... The preparation steps are as follows: S1: The coupling agent is used to modify the surface of mullite whiskers and carbon fibers to obtain modified mullite whiskers and carbon fibers. S2: Mix the epoxy resin and curing agent, and stir to disperse evenly; S3: Add the modified mullite whiskers and carbon fibers obtained in S1 to S2, and stir in a high-speed mixer for 10-15 minutes at a stirring speed of 2000-3000 r / min to obtain a primary premix; disperse the primary premix by ultrasonication to obtain a premix. S4: Add defoamer, antioxidant and release agent to the premix obtained in S3, mix evenly to obtain slurry; S5: The slurry is applied to the required mold, and kept at a constant temperature and pressure to obtain a high-strength and high-toughness epoxy resin for the aerospace industry.

8. The method for preparing high-strength and high-toughness epoxy resin for the aerospace field according to claim 7, characterized in that... The surface modification treatment of mullite whiskers and carbon fibers in S1 is carried out in the following steps: the mullite whiskers are dried at 120-130℃ for 3 hours and the carbon fibers are dried at 110-120℃ for 2 hours, and then they are mixed and placed in a mixer; the coupling agent is diluted with ethanol, atomized and sprayed into the mixer, the mixer speed is 1200-1500 r / min, and the mixture is stirred at room temperature for 40-50 min; the resulting mixture is dried at 90-100℃ for 2-3 hours, thus achieving the surface modification of mullite whiskers and carbon fibers.