On July 31, the National Development and Reform Commission and the Ministry of Commerce revised the "Catalogue of Industries Encouraging Foreign Investment" and formed the "Catalogue of Industries Encouraging Foreign Investment (2020 Edition) (Draft for Solicitation of Comments)" and solicited public opinions.
Among them, in the catalog of advantageous industries for foreign investment in the central and western regions, Inner Mongolia Autonomous Region, Liaoning Province, Jilin Province, Heilongjiang Province, Anhui Province, Jiangxi Province, Henan Province, Hubei Province, Hunan Province, Guangxi Zhuang Autonomous Region, Chongqing City, Sichuan Province, Guizhou Province and Gansu Province both mentioned: the application of lightweight materials in the manufacture of auto parts (high-strength steel, aluminum-magnesium alloys, composite plastics, powder metallurgy, high-strength composite fibers, etc.). It can be seen that with the further rapid development of the automotive industry in recent years, automotive plastics are gradually becoming the new favorite of the plastics industry.
What are the advantages of replacing steel with plastic?
First of all, a very important difference between plastics and other materials is that it is easy to process and shape at one time, and the processing cost is low, the time is short, and the accuracy is guaranteed. With the permission of the experiment and the customer's permission, it can even be recycled for secondary molding. From the perspective of economic benefits, plastics undoubtedly have its advantages. In addition, by adding different fillers, plasticizers, hardeners and elastomers, it can also be made into modified materials to meet the needs and requirements of different parts of the car.
Secondly, we are more inclined to choose materials with higher than light intensity in the selection of automotive materials. The specific strength refers to the ratio of the material's tensile strength to the apparent density of the material. The higher the specific strength, the higher the quality of the material used to achieve the corresponding strength. The lighter. Structural materials with higher specific strength can meet the strength requirements with a smaller cross section as much as possible, and at the same time, the self-weight of the structure can be greatly reduced. Compared with metal materials, modified plastics and composite materials have lower density and higher specific strength.
Finally, because the plastic product itself is lighter and has good elastic deformation, it can absorb a large amount of collision energy, and the cushioning effect on strong impact is significantly better than other materials, which will better protect the vehicle and occupants. ; Plastic also has the function of absorbing and attenuating vibration and noise, which can improve the comfort of riding; strong corrosion resistance, local damage will not easily corrode.
Which modified plastics will benefit from lightweight design?
At present, the common modified plastics and composite materials mainly include modified PP, modified PVC, modified PE, fiber composite materials, metal matrix composite materials, and thermoplastic resin composite materials.
The role and status of modified plastics in the automotive industry are becoming more and more obvious. Polypropylene (PP), acrylonitrile-butadiene-styrene copolymer (ABS), polyamide (PA), polycarbonate (PC) , Polyoxymethylene (POM), polybutylene terephthalate (PBT), reinforced polyurethane (PRT) and polyvinyl chloride (PVC) and other plastics have been widely used in automobiles.
As an important part of automobile lightweight, the materials used in bumpers and other parts must reduce the body quality and manufacturing cost as much as possible while ensuring the strength and safety of the body. The bumper can absorb the energy generated in the collision of the vehicle and reduce the damage to the body parts and passengers. It needs to have good impact resistance, weather resistance, paint adhesion and other properties, PP, PC/ABS, PC/PBT , PP foam materials, TPO, glass fiber reinforced PP materials are more common in plastic bumpers.
Due to the long-term influence of factors such as the sun, rain and other weather and driving bumps, the rearview mirror material needs to have a certain degree of weather resistance. Taking into account the requirements of temperature, humidity, strength, impact and bending performance, and the materials are not easy to age, corrosion resistance, injection performance and painting performance, etc., materials generally can be heat-resistant ABS, PC, ASA, PBT%2BGF etc.
To ensure that the luggage rack is not damaged under various complex conditions of use, the material is required to have sufficient fatigue strength to ensure that the luggage rack does not cause serious fatigue damage when the car is driving fast and emergency braking. Generally, PC/PBT can be used , PC/ASA, PC/ABS, ASA and other materials. Glass fiber reinforced unsaturated polyester sheet molding compound (SMC) can be selected for the luggage compartment cover. This material can be used for exterior trims such as engine hood, roof cover, front fender and tail panel.
Car lights play an important role in the safe driving of vehicles. The materials used to make car lights need to have good impact resistance, light transmittance, weather resistance, and easy processing. The lampshade generally uses PC or PMMA materials. The seat is generally made of ABS material.
In terms of automotive interiors, parts such as inner door panels and instrument panels can be made of micro-foamed PP material, which is a kind of polypropylene material as the matrix, and the middle layer of the product is sealed from ten to tens of micrometers through the injection process. Microporous and dense skin structure on both sides, low density and high elasticity, are potential stocks in lightweight materials. The seat, floor and footrest can be made of glass fiber mat reinforced thermoplastic composite material (GMT).
The PA/PPO plastic has the advantages of high fluidity, high toughness, and electrostatic sprayability, which can replace metal in automotive exterior trim such as fenders. In addition, because of its high temperature resistance, it can also be used in some parts of automobile engines, fuel tanks or battery shell parts after being modified by different processes or mixed with other materials.