A two-step preparation method of a lightweight and high-strength fiber composite product using HSM thermal self-expanding prefabricated core material

Abstract

The invention discloses a two-step preparation method for a lightweight and high-strength fiber composite product using HSM heat self-expanding prefabricated core material. First put the plastic preformed thermal self-expanding high-energy glue into the core material mold of the product and tighten the mold, heat at 80-100°C for 3-30 minutes, and micro-expand, and the volume ratio before and after micro-expansion is 1.01-1.5, full of Core mold cavity, cooling and demoulding, then wrapping fiber prepreg cloth into the molding mold and tightening the mold, heating at 120-180°C for 10-60 minutes, the heat self-expanding high-energy adhesive that can be molded and preformed continues to be heated. Expansion force from the inside to the outside, the fiber prepreg is solidified at high temperature; cooled and demoulded to take the piece. The method of the present invention is suitable for wrappers of fiber prepregs that require three-dimensional support and complex-shaped products whose thickness exceeds 1 cm.

Description

technical field [0001] The invention relates to the field of fiber composite molding, in particular to a two-step preparation method for a light-weight and high-strength fiber composite product using HSM thermal self-expanding prefabricated core material. Background technique [0002] The traditional preparation methods of fiber composite products are as follows; [0003] First, the hand lay-up process has problems in an atmospheric pressure environment. Most of the hand-lay-up resins are solvent-based, which has a heavy smell and is not environmentally friendly, which is not conducive to the health of the operators. It requires a long room temperature curing production cycle and is basically in a phase-out state; [0004] Second, the core material molding process, the pressure of the product during molding comes from an external press, that is, the hard foam core material is used to outsource the cement layer and then the fiber prepreg is wrapped to preform. The hard foam m...

AI Technical Summary

Problems solved by technology

[0003] First, the hand lay-up process has problems in an atmospheric pressure environment. Most of the hand-lay-up resins are solvent-based, which has a heavy smell and is not environmentally friendly, which is not conducive to the health of the operators. It requires a long room temperature curing production cycle and is basically in a phase-out state;

[0004] Second, the core material molding process, the pressure of the product during molding comes from an external press, that is, the hard foam core material is used to outsource the cement layer and then the fiber prepreg is wrapped to preform. The hard foam materials used include PMI , PU, ​​PVC, balsa wood, etc. need to be cut into pre-shaped core materials by CNC, put into the mold cavity, heated and pressurized, and the resin is cured to form the product. The efficiency is high, and the existing problems: 1. The process is complicated and hard The foam core material needs to be cut by CNC in advance, which increases equipment investment. 2. An additional bonding layer must be added between the foam core material and the fiber prepreg, which increases the material cost. 3. Due to uneven force, it is difficult to obtain an excellent product appearance; 4. 1. There is no expansion force from the inside to the outside of the core material during the molding process, so the interlayer bonding force of the fiber is not good, the bonding is uneven, and it is easy to delaminate, resulting in a decrease in the overall strength of the product; 5. Large-sized workpieces require large tonnage high equipment investment, which is not conducive to popularization

[0007] 1. Sheet-like high-energy glue is only suitable for preparing products with 2D effects when preforming carbon cloth; 2. The dimensional accuracy of preformed products is not accurately controlled, and the defect rate is high; 3. The thickness of the product exceeds 1cm, carbon cloth The difference between the size of the preform and the size after molding is large, which will cause the fibers to be pulled by the expansion force during the expansion molding process, resulting in stress concentration, and the interlayer bonding force inside the product is inconsistent, especially the quality of complex and thick products is uncontrollable