Method for improving interlaminar shear strength of medium/low-temperature cured prepreg by using polyurethane prepolymer

A polyurethane prepolymer and prepreg technology, applied in the field of composite materials, can solve problems such as low bonding performance, and achieve the effects of high peel strength, excellent lap shear strength, and good impact resistance.

Active Publication Date: 2013-05-22
中威北化科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of low interfacial bonding performance of medium and low temperature curing prepreg, through a polyurethane prepolymer to improve the preparation method of interlayer shear str

Method used

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  • Method for improving interlaminar shear strength of medium/low-temperature cured prepreg by using polyurethane prepolymer

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Add isophorone diisocyanate (IPDI) and polypropylene oxide into the reactor according to the molar ratio of 4:3, and react at 70°C for 6 hours to obtain an isocyanate-terminated polyurethane prepolymer with a molecular weight of 2500. Add 15 parts (mass The number of parts is calculated based on the final amount of epoxy resin used as 100 parts, the same below) The isocyanate-terminated polyurethane prepolymer and bisphenol A glycidyl ether epoxy resin are reacted in a stirred tank at 60°C for 8 hours, and then bisphenol A is added Stir glycidyl ether epoxy resin and glycidyl amine epoxy resin evenly to obtain a modified epoxy resin matrix, then add 10 parts of dicyandiamide curing agent and 5 parts of urea derivative accelerator, mix evenly and vacuum remove Bubble, epoxy resin system for prepreg preparation. The above resin system is coated with a film machine, and then compounded with reinforcing fibers through a compound machine to prepare a unidirectional carbon fi...

Embodiment 2

[0019] Add diphenylmethane diisocyanate (MDI) and polyethylene glycol into the reactor at a molar ratio of 5:3, and react at 70°C for 5 hours to obtain an isocyanate-terminated polyurethane prepolymer with a molecular weight of 1800. 10 parts of isocyanate-terminated React polyurethane prepolymer with bisphenol F glycidyl ether epoxy resin in a stirred tank at 80°C for 7 hours, then add bisphenol A glycidyl ether epoxy resin and novolac epoxy resin and stir evenly to obtain a modified epoxy resin Then add 6 parts of modified dicyandiamide curing agent and 3 parts of urea derivative accelerator, mix evenly and vacuum defoam to prepare epoxy resin system for prepreg. The above resin system is coated with a film machine, and then compounded with a reinforced fiber fabric through a compound machine to prepare a carbon fiber fabric prepreg. The cut prepreg is placed in a mold, and it is pressurized and cured at 100°C for 3 hours to obtain a composite. Material plate, the test inter...

Embodiment 3

[0021] Add toluene diisocyanate (TDI) and polyethylene glycol into the reactor at a molar ratio of 2:1, and react at 70°C for 4 hours to obtain an isocyanate-terminated polyurethane prepolymer with a molecular weight of 1000, and 5 parts of isocyanate-terminated polyurethane React the prepolymer with bisphenol A glycidyl ether epoxy resin in a stirred tank at 100°C for 5 hours, then add bisphenol A glycidyl ether epoxy resin and novolac epoxy resin and stir evenly to obtain a modified epoxy resin matrix , and then add 5 parts of dicyandiamide curing agent and 1 part of urea derivative accelerator, mix evenly and vacuum defoam to prepare the epoxy resin system for prepreg. The above resin system is coated with a film machine, and then compounded with reinforcing fibers through a compound machine to prepare a unidirectional carbon fiber prepreg. The cut prepreg is placed in a mold, and it is pressurized and cured at 120°C for 1.5 hours to obtain a composite Material plate, the t...

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Abstract

The invention provides a method for improving interlaminar shear strength of medium/low-temperature cured prepreg by using polyurethane prepolymer. The method comprises the following steps: firstly, reacting isocyanate with polyether polyol according to a controllable ratio to obtain a terminal isocyanate polyurethane prepolymer; grafting the terminal isocyanate polyurethane prepolymer to a bisphenol type epoxy resin, and adding a mixed epoxy resin to obtain a modified epoxy resin matrix; uniformly mixing the modified epoxy resin matrix with a curing agent and an accelerant to obtain a resin system for prepreg; and finally, preparing the resin system into a rubber film, compounding the rubber film with reinforced fibers or fabrics so as to prepare the medium/low-temperature cured prepreg with excellent adhesiveness. The prepreg preparation process is reasonable, the bonding strength of the resin system and fiber is high, the interlaminar shear strength of the composite material is obvious improved, and the method is particularly suitable for low-temperature cured prepreg.

Description

technical field [0001] The invention relates to the field of composite materials, in particular to a preparation method for polyurethane prepolymers to improve interlayer shear strength of medium and low temperature curing prepregs. Background technique [0002] With the maturity of prepreg technology, prepreg is more and more widely used in the manufacture of large composite components, such as wind power blades, automotive composite components, etc. Due to the unique advantages of medium and low temperature curing prepregs in raw materials, technology, production technology, applicability, etc., especially it can save the cost of molds for large components and prolong the service life of molds, so medium and low temperature curing prepregs are becoming more and more popular. Favored. [0003] Due to the different thermal expansion coefficients of fibers, resins, and mold materials, the composite material shrinks severely after curing at high temperature, and internal stre...

Claims

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Application Information

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IPC IPC(8): C08J5/24C08J5/04C08L75/04C08K7/06C08K3/04C08G18/58C08G59/50
Inventor 李刚杨小平李旭苏清福刘大伟
Owner 中威北化科技有限公司
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