Previously, I told my friends about "what are the heating methods of SMC FRP mold" in the FRP molding process. Due to the particularity and superiority of FRP, today I'd like to briefly talk about the requirements of SMC FRP molding process for glass fiber with friends. The details are as follows:

As we all know, SMC FRP molding process is mainly used for the shell, chassis, bumper, spoiler, high-voltage switch cabinet and building water tank plate in the automotive industry. The glass fiber content of glass fiber can reach 30% in the glass fiber reinforced plastic products of SMC molding process. The performance requirements of SMC for glass fiber are as follows:

1. Excellent clustering and very low solubility. Proper permeability. It is required that the yarn has excellent bunching ability and low solubility. In this way, it can ensure that the resin paste with high viscosity can vertically penetrate the thick short cut glass fiber stacking layer in the production process of SMC sheet. If the yarn is not well bunched and its solubility in styrene is high, and the resin paste is opened when it meets the resin paste, the resin paste is difficult to penetrate, resulting in a white silk layer in the middle. No resin impregnation. At the same time, when the yarn is opened early in the resin paste, the fiber can not flow with the resin during molding, resulting in uneven distribution of fiber, more in the middle and almost no glass fiber at the edge. This requires that the insoluble content of the main film-forming agent of the sizing agent should be more than 90%, and the yarn has no tendency of monofilament and is easy to be formed.

2. High stiffness, preferably greater than 160 mm, some foreign SMC yarn stiffness to 180 mm. This requires high hardness and strength of sizing film, and high solid content of sizing agent, sometimes up to 13%, to ensure oil content of yarn (Lou is more than 1.5%).

3. Excellent cutting performance, good yarn rigidity and less static electricity. On the premise of ensuring the uniform force of each yarn, each yarn can be dispersed and arranged in parallel. This ensures easy dispersion on the unit and even dispersion after settlement. If we want to further improve the cutting and clustering properties of the yarn, we can also add 0.2-1% polyglutamic acid emulsion into the formula. The main film forming agent in the formulation is cross-linked PVAc emulsion. Crosslinking monomer is added to the emulsion synthesis, and crosslinking agent can also be added at the outer side of the sizing agent. When the film is formed, the macromolecular network structure is formed due to the action of crosslinking agent, which improves the rigidity and strength of the membrane, and makes it insoluble in styrene. The composite coupling agent is also used to improve the stiffness of the yarn. In order to ensure the crosslinking reaction of film forming agent, the drying temperature of SMC yarn precursor cylinder should be high, generally up to 135 ` C, and the time should be more than 10 hours.

Summary: the above is Ningguang mold small editing and finishing of the "simple talk: SMC glass fiber reinforced plastic molding process for glass fiber performance requirements" all the content, I hope to help friends in the industry. If you want to know more about SMC mold, BMC mold and so on, please collect our website and pay attention to the update of our website in time.