【RTM】Can Changing the Reinforcement Material Make the Resin Flow Better?

 

RTM (Resin Transfer Molding) process is the abbreviation of resin transfer molding process. Its working principle is: the reinforcement material is laid in the mold cavity formed by the upper and lower molds in advance, and the resin glue is injected into the mold cavity with a special pressure equipment after the mold is closed. After the reinforcement material is infiltrated, it is solidified and demolded to form the product.

In this process, how to effectively let the resin infiltrate the reinforcement material is the most critical step. If the infiltration is poor in the middle, the product will be scrapped. In addition to considering factors such as viscosity and gel time when selecting resin, how to improve the flow diversion effect of the reinforcement material has also become a research direction, and closed mold mat was born for this purpose.

Closed Mold Mat, as the name suggests, is the glass fiber mat used in the closed mold process. We know that there are many closed mold processes, including common vacuum infusion, RTM, molding, etc. But the closed mold process here generally refers to the RTM process.

Usually, the closed mold mat has three layers. The upper and lower surface layers are made of glass fiber chopped yarn, and the middle layer is PP guide mat, which are tied together by polyester thread to form a sandwich structure. Therefore, the closed mold mat is also called PP sandwich mat. Among them, the chopped yarn is used as a reinforcing material to provide strength; the PP mat plays a role in rapid guide during the resin introduction process.

 

The use of closed mold mat in the RTM process has the following advantages:

①Easy to lay and can adapt to products of different shapes;

②The product is combined by binding wire, which does not contain chemical adhesives, has good compatibility with resin, is resistant to erosion, and is not easy to wrinkle;

③The fiber content is stable, which can ensure the stability of the product;

④Due to the PP guide layer, the flow and permeability of the resin are better;

⑤According to the different thickness of the product, there are multiple combinations to reduce the number of layers.

Although closed mold mat has many advantages, its surface is all chopped yarn, non-continuous fiber, and the middle PP layer does not provide strength. Therefore, if used alone, the strength is poor. Generally, it will be used together with axial cloth or composite mat according to the requirements of the product.

In order to solve the problem of weak strength, there are actually other combinations, such as replacing the upper and lower chopped yarns with axial cloth or Woven Roving Mat. With continuous fibers, its strength will be significantly improved. At present, there are also some manufacturers on the market that can provide this customized version of the product.

In general, closed mold mat improves the flow and wetting effect of resin from the perspective of reinforcing materials, thereby improving the qualified rate of products. Technology and materials are always complementary, and good technology also requires good materials.

The above is the reinforcing material commonly used in RTM process introduced by Dymriton – Closed Mold Mat. If you have any questions during use, or want to purchase this material, you can leave a message below the article, or add me: +86 13813545782, and communicate together. Remember to forward the article to your circle of friends so that more people can gain something.