From the domestic and international applications, the amount of glass chopped strand mat at home and abroad is completely different. This article will discuss whether it is necessary to apply chopped strand mat from the perspective of shipbuilding. The details are as follows.
Compactness
The chopped strand mat has the advantages of large void ratio and high resin content, so that the prepared glass fiber reinforced plastic has a small gap ratio and good impermeability. However, from the perspective of the process of FRP production, the leakage does not depend entirely on the variety of reinforcing materials, but more on the operation of the constructor. Because the glass hull was formed using glass fiber cloth before the development of the chopped strand mat, the boat did not leak after paying attention to the gingham fabric and controlling the operation quality. In the early 1980s, when foreigners visited the Changzhou FRP Shipyard, they all saw glass fiber cloth when they formed the boat. They issued a sigh of “material waste”, but did not raise the problem of leakage.
Interlayer bonding performance
The use of a felt-pull layer structure can improve the bonding performance between the layers, which has a certain effect when the hull construction uses multiple molding methods. The customary practice of foreign companies is to complete the hull thickness in multiple times. Each time a blanket is applied, the surface quality is checked after curing and polished, and then the next layer is formed. This method is beneficial to ensure the quality of the hull. In the past, local Chinese companies were accustomed to forming small and medium-sized boats in a single time. Even large-scale boats were only completed in 2 to 3 times. The thickness of each operation was less than 5 mm, and no thin layer of felt was used. Molding method. However, as long as the operator is skilled and the process is properly arranged, the adhesion between the layers is increased by the use of sanding, etc., and the chopped felt is not affected.
Product surface quality
FRP products can improve the surface of the product when the surface felt and chopped strand mat are used near the surface layer. At present, when the surface of the FRP boat is required to have a high finish, in addition to processing the surface of the ship mold to a high degree of finish, it is also necessary to use a surface felt of 30 to 50 m after the gel coat layer, and then use a short ≯350 g/m. By cutting the felt, a higher surface finish can be obtained (but the high-gloss surface quality is achieved by a rigorous and efficient manufacturing process and does not depend entirely on the materials used).
Operational efficiency
FRP made of chopped strand mat is made of glass fiber cloth with similar specifications than chopped strand mat, and the thickness of FRP is increased by about 60% to 70%. This thickening effect can reduce the number of working layers when using glass fiber cloth completely. This can improve operational efficiency. But this is not very attractive for SMEs in China, because this advantage is negligible compared to the increase in material costs.
In summary, although the use of chopped strand mat has certain advantages, it is still a cost factor because of the decisive effect, so far, the chopped strand mat has not been widely used. At present, only some shipbuilding companies use a smaller number of chopped strand mats for the purpose of improving surface quality. Only after the price of chopped strand felt is lower than the price of fiberglass cloth will it be used in a wider range of applications on FRP boats.