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CN-122013501-A - Dipping and airing method of carbon fiber soft felt

CN122013501ACN 122013501 ACN122013501 ACN 122013501ACN-122013501-A

Abstract

The invention discloses an impregnation and air-drying method of a carbon fiber soft felt, which comprises the steps of firstly pretreating the carbon fiber soft felt by a nitric acid solution with specific concentration, and then preparing an impregnant containing components such as epoxy resin, a curing agent and the like, wherein microcapsule wall materials are of a gelatin-polyurea multilayer structure and contain a repairing agent. Intermittent stirring, pressure and vacuum assist are adopted during the impregnation operation, so that the impregnating agent is ensured to fully permeate. The impregnant is solidified by controlling the temperature, the humidity and the turn-over time during the airing. The preparation of the microcapsule involves the steps of inner gelatin, outer polyurea coating, urea formaldehyde resin polymerization and the like, and gamma-aminopropyl triethoxysilane is added for treatment when the microcapsule is formed. The method can solve the problems of uneven impregnation, insufficient penetration depth, unstable microcapsule performance and the like in the traditional impregnation method, realize that the impregnant uniformly and fully permeates into the carbon fiber soft felt, and improve the performance and stability of the microcapsule, thereby improving the comprehensive performance of the carbon fiber soft felt composite material.

Inventors

  • WANG YONGCHENG
  • JIANG KELI
  • PENG XIYU
  • SUN GONGJUN
  • Yin Houming

Assignees

  • 江苏华炘新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260312

Claims (10)

  1. 1. The dipping and airing method of the carbon fiber soft felt is characterized by comprising the following steps of: (1) Pretreatment of carbon fiber soft felt Soaking the carbon fiber soft felt in 30-40% nitric acid solution for 3-6h; (2) Preparation of impregnant The impregnant comprises, by weight, 6-7 parts of epoxy resin, 1-2 parts of fatty amine curing agent, 0.5-0.8 part of n-butyl alcohol, 0.8-1.2 parts of rubber elastomer toughening agent and 0.5-0.8 part of microcapsule, and stirring the components in a stirring container at a rotating speed of 300-500r/min for 15-30min to uniformly mix the components; The wall material of the microcapsule is of a multi-layer structure, the inner layer is gelatin with flexibility, the outer layer is polyurea, melamine is added into the wall material in the synthesis process to serve as a cross-linking agent, the microcapsule contains a repairing agent, and the repairing agent is a combination of epoxy resin and a curing agent; (3) Dipping operation Pouring the impregnant prepared in the step (2) into an impregnating tank, intermittently stirring at a stirring speed of 200-300r/min by adopting a paddle stirrer, stopping stirring for 2min each time, and controlling the impregnating temperature at 40-60 ℃ to ensure that the impregnant is uniformly distributed and keeps good fluidity; Immersing the carbon fiber soft felt into an immersing tank for 15-30min, placing the immersing tank into a sealed container, filling nitrogen into the sealed container, lifting the air pressure in the container, and accurately controlling the pressure by using a pressure sensor and an air pressure regulating valve to maintain the pressure within the range of 0.1-0.3MPa, so as to ensure that the impregnant fully permeates into the carbon fiber soft felt; vacuum assist is used in the impregnation process, the carbon fiber soft felt and the impregnant are placed in a vacuum environment with the vacuum degree of 0.05-0.1MPa for 5-10min and then restored to normal pressure or micro positive pressure, and the micro positive pressure range is 0.01-0.03MPa, so that the impregnation effect is further improved; (4) Air drying treatment Taking out the impregnated carbon fiber soft felt from the impregnation tank, dripping excessive impregnant for 5-10min, spreading the carbon fiber soft felt on a drying rack in a drying chamber, turning over the carbon fiber soft felt every 2-3h at the temperature of 20-30 ℃ and the relative humidity of not more than 60%, and drying for 24-72h until the impregnant is completely solidified.
  2. 2. The method for impregnating and airing the carbon fiber soft felt according to claim 1, which is characterized in that: in the step (1), the concentration of the nitric acid solution is 35%, and the carbon fiber soft felt is soaked in the nitric acid solution for 4 hours.
  3. 3. The method for impregnating and airing the carbon fiber soft felt according to claim 1, which is characterized in that: In the step (2), 6.5 parts of epoxy resin, 1.5 parts of fatty amine curing agent, 0.6 part of n-butyl alcohol, 1 part of rubber elastomer toughening agent and 0.6 part of microcapsule are adopted in the impregnant, and the stirring speed is 400r/min and the stirring time is 20min.
  4. 4. The method for impregnating and airing the carbon fiber soft felt according to claim 1, which is characterized in that: in the step (3), the stirring speed of the paddle stirrer is 250r/min, the soaking temperature is 50 ℃, the soaking time is 20min, the applied pressure is 0.2MPa, the vacuum environment treatment time is 8min, and the micro positive pressure after recovery is 0.02MPa.
  5. 5. The method for impregnating and airing the carbon fiber soft felt according to claim 1, which is characterized in that: in the step (4), the temperature of the drying chamber is 25 ℃, the relative humidity is 50%, the turnover interval time is 2.5h, and the drying time is 48h.
  6. 6. The method for impregnating and airing the carbon fiber soft felt according to claim 1, which is characterized in that: the preparation of the microcapsule comprises the following steps: s1, preparation of inner wall material Weighing gelatin and deionized water according to a mass ratio of 1:10, adding the gelatin into the deionized water, heating and stirring in a water bath at 55 ℃ to completely dissolve the gelatin and form gelatin solution with a certain concentration; S2, preparation of repairing agent Mixing epoxy resin and fatty amine curing agent according to the ratio of 10:1, and adding proper amount of acetone or butanone as diluent to prepare repairing liquid, wherein the addition amount of the diluent is 10% -20% of the total mass of the repairing agent; s3, coating the gelatin inner layer Dispersing the repairing liquid prepared in the step S2 in the gelatin solution prepared in the step S3, stirring at a speed of 1000-1500r/min by using a high-speed stirrer to form tiny liquid drops of the repairing liquid, and wrapping the tiny liquid drops by the gelatin solution to form a primary structure of wrapping the repairing liquid by taking gelatin as an inner wall material; S4, preparation of outer wall material The synthesis of polyurea, namely weighing toluene diisocyanate TDI and ethylenediamine according to the mass ratio of 1:1, adding the toluene diisocyanate TDI and the ethylenediamine into acetone, wherein the dosage of the acetone is 3-5 times of the total mass of the toluene diisocyanate TDI and the ethylenediamine, and reacting for 3 hours at 60 ℃ to form polyurea so as to completely dissolve the toluene diisocyanate TDI and the ethylenediamine; S5, coating the polyurea outer layer Slowly adding the gelatin-coated repairing liquid drop dispersion system formed in the step S3 into the polyurea solution prepared in the step S4, and simultaneously keeping stirring, wherein polyurea can be gradually deposited on the surface of the gelatin-coated liquid drop in the stirring process to form an outer layer coating; S6, packaging Dispersing the repairing liquid coated by the polyurea outer layer in an aqueous medium, and forming water-in-oil emulsion by using sodium dodecyl sulfate as an emulsifier, wherein the amount of the emulsifier is 1% -3% of the mass of the repairing liquid; s7, synthesis of urea resin prepolymer Weighing 10 parts of urea, 20 parts of formaldehyde, 0.5 part of ammonium chloride and 1 part of melamine, firstly adding urea and formaldehyde into a reaction container, performing polycondensation reaction at a pH value of 4 and a temperature of 70 ℃, then adding ammonium chloride as a catalyst, reacting for 3 hours to form urea-formaldehyde resin prepolymer, and adding melamine as a cross-linking agent in the synthesis process of the urea-formaldehyde resin; s8, microcapsule formation Dropping urea-formaldehyde resin prepolymer into emulsion, polymerizing urea-formaldehyde resin on the surface of repairing liquid drop to form microcapsule at 50 deg.C, stirring speed of 800r/min and pH value of 8, filtering and washing to obtain microcapsule with particle size of 10-100 μm.
  7. 7. The method for impregnating and airing the carbon fiber soft felt according to claim 6, wherein the method comprises the following steps of: in step S2, the addition amount of the diluent in the preparation of the repairing agent is 15%; in the step S3, when the gelatin wrapping core is formed, the stirring speed of the high-speed stirrer is 1200r/min; in step S6, the amount of emulsifier used in the formation of the water-in-oil emulsion was 2%.
  8. 8. The method for impregnating and airing the carbon fiber soft felt according to claim 7, wherein the method comprises the following steps of: in step S8, when the urea-formaldehyde resin prepolymer is dripped into the water-in-oil emulsion to form the microcapsule, gamma-aminopropyl triethoxysilane is added according to 3% of the total weight of the wall material, firstly, the gamma-aminopropyl triethoxysilane is dissolved in ethanol to prepare a solution with the concentration of 30%, and then the solution is slowly dripped or added into a reaction system forming the microcapsule.
  9. 9. The method for impregnating and airing the carbon fiber soft felt according to claim 8, wherein the method comprises the following steps of: in step S8, the concentration of the gamma-aminopropyl triethoxysilane solution is 5-15%, and the solution is slowly dripped or added into a reaction system forming the microcapsule and then reacted for 1.5h at 40 ℃.
  10. 10. The method for impregnating and airing the carbon fiber soft felt according to claim 9, wherein the method comprises the following steps of: the concentration of the gamma-aminopropyl triethoxysilane solution is 10%.

Description

Dipping and airing method of carbon fiber soft felt Technical Field The invention relates to the technical field of carbon fiber composite material processing, in particular to a dipping and airing method of a carbon fiber soft felt. Background The carbon fiber soft felt has the excellent characteristics of light weight, high strength, high modulus and the like, and is widely applied to various fields of aerospace, automobile industry, sports equipment and the like. However, in practical application of the carbon fiber soft felt, in order to enhance the performance and the functionality of the carbon fiber soft felt, the carbon fiber soft felt is often required to be subjected to impregnation treatment, so that the impregnant fully permeates into the fiber, and the comprehensive performance of the composite material is further improved. The traditional impregnation method has some defects, such as uneven impregnation, easy occurrence of partial insufficient impregnation or excessive impregnation, which can affect the performance stability of the composite material, limited penetration depth of the impregnant, inability of fully filling pores and fiber gaps in the carbon fiber soft felt, difficulty in achieving the ideal state of the strength and toughness of the composite material, imperfect preparation and application technology of the microcapsule, poor performance and stability of the microcapsule, and incapability of effectively playing the functions of repairing and the like. Therefore, the impregnating and airing method for the carbon fiber soft felt can enable the impregnating agent to uniformly and fully permeate into the carbon fiber soft felt, and has important significance in improving the performance and stability of the microcapsule. Disclosure of Invention The invention aims to provide an impregnation and air-drying method for a carbon fiber soft felt, which is used for solving the problems of uneven impregnation, insufficient penetration depth, unstable microcapsule performance and the like in the traditional impregnation method, realizing that an impregnant uniformly and fully permeates into the carbon fiber soft felt, improving the performance and stability of the microcapsule, improving the comprehensive performance of a carbon fiber soft felt composite material and meeting the requirements of different fields on a high-performance carbon fiber soft felt. In order to achieve the aim, the invention provides the following technical scheme that the dipping and airing method of the carbon fiber soft felt comprises the following steps: (1) Pretreatment of carbon fiber soft felt Soaking the carbon fiber soft felt in 30-40% nitric acid solution for 3-6h; (2) Preparation of impregnant The impregnant comprises, by weight, 6-7 parts of epoxy resin, 1-2 parts of fatty amine curing agent, 0.5-0.8 part of n-butyl alcohol, 0.8-1.2 parts of rubber elastomer toughening agent and 0.5-0.8 part of microcapsule, and stirring the components in a stirring container at a rotating speed of 300-500r/min for 15-30min to uniformly mix the components; The wall material of the microcapsule is of a multi-layer structure, the inner layer is gelatin with flexibility, the outer layer is polyurea, melamine is added into the wall material in the synthesis process to serve as a cross-linking agent, the microcapsule contains a repairing agent, and the repairing agent is a combination of epoxy resin and a curing agent; (3) Dipping operation Pouring the impregnant prepared in the step (2) into an impregnating tank, intermittently stirring at a stirring speed of 200-300r/min by adopting a paddle stirrer, stopping stirring for 2min each time, and controlling the impregnating temperature at 40-60 ℃ to ensure that the impregnant is uniformly distributed and keeps good fluidity; Immersing the carbon fiber soft felt into an immersing tank for 15-30min, placing the immersing tank into a sealed container, filling nitrogen into the sealed container, lifting the air pressure in the container, and accurately controlling the pressure by using a pressure sensor and an air pressure regulating valve to maintain the pressure within the range of 0.1-0.3MPa, so as to ensure that the impregnant fully permeates into the carbon fiber soft felt; vacuum assist is used in the impregnation process, the carbon fiber soft felt and the impregnant are placed in a vacuum environment with the vacuum degree of 0.05-0.1MPa for 5-10min and then restored to normal pressure or micro positive pressure, and the micro positive pressure range is 0.01-0.03MPa, so that the impregnation effect is further improved; (4) Air drying treatment Taking out the impregnated carbon fiber soft felt from the impregnation tank, dripping excessive impregnant for 5-10min, spreading the carbon fiber soft felt on a drying rack in a drying chamber, turning over the carbon fiber soft felt every 2-3h at the temperature of 20-30 ℃ and the relative humidity of not more than 60%, and drying f