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Expanded Polypropylene (EPP) is a high-crystalline polypropylene/CO2 gas composite material with excellent performance, which is a pure hydrocarbon prepared by using high melt strength polypropylene as a plastic matrix and CO2 gas as foaming agent under high temperature and high pressure conditions. EPP products have excellent anti-vibration energy absorption performance, high recovery rate after deformation, good heat resistance, good chemical resistance and light weight, can be 100% recyclable, belong to green and environmentally friendly materials, and can be recycled and reused. It can be widely used in fields that require lightweight, environmental protection, and energy absorption. Therefore, since the advent of EPP, it has been widely used in the field of automobile manufacturing, and the application of EPP in commercial vehicles has gradually increased.
As one of the parts with the largest surface area in the car, the top cover trim panel has a unique decorative effect, and can meet the requirements of heat insulation, sound absorption, sound insulation, and protect the head of personnel. Interior panels are laminated by a decorative layer and a base material by hot pressing. There are two commonly used substrates: Glass Mat reinforced Thermoplastics (GMT) and Polyurethane-fiber board(PU glass fiber board), the substrate plays a supporting role, and it is also the key layer to realize the shape and performance of the ceiling. It is also important to study the choice of substrate for headliner interior panels.
Taking the roof cover interior panel of commercial vehicle light truck as an example, the application of EPP material in the roof cover interior panel was studied, and the differences in formability and performance of EPP material, GMT plate and PU fiberglass panel on the roof cover interior panel of commercial vehicle were compared. Through the comparison of weight reduction rate, molding cycle, sound absorption, environmental protection, and thermal insulation performance, the conclusion is as follows.
a.EPP top cover interior panel has obvious lightweight advantages, and the weight reduction rate can reach 32%.
b. From the perspective of the complexity of the production process and process, the EPP substrate is made of granules, and the molding process and process are more complex than the dry molding roof, and the complexity of the EPP top cover > PU top cover = GMT top cover, and the EPP needs to consider the preforming mold.
c. EPP material does not have the loose porous structure of the middle layer after GMT and PU material molding, and is inferior to the top cover interior panel of these two materials in terms of sound insulation and noise reduction.
d. The deflection of EPP top cover can meet the needs of the product, but it is worse than GMT and PU materials.
e. EPP top cover is better than GMT material and PU glass fiber board material in terms of thermal insulation performance, odor and atomization performance.
