Application of polymer materials in the automotive field

With the increase of people's awareness of environmental protection and increasingly serious environmental problems, car lightweighting has become a growing concern of people. Along with the breakthrough of polymer synthesis and processing technology, more and more polymer materials appear in automotive production applications, such as polyvinyl chloride (PVC), polycarbonate (PC), polyethylene (PE), and poly. Polymer materials such as propylene PP, polyurethane (PUR), and polyamide (PA) have been widely used in the field of automobile manufacturing.

01

Polymer material performance characteristics

A, low density

One of the most prominent advantages of polymer materials is their light weight and high strength. The average density of various polymers is only 15-20% of ordinary steel. This advantage can greatly reduce the weight of the car. Improve vehicle acceleration and improve vehicle control stability, noise, and vibration. From the perspective of collision safety, the inertia is small during collision and the braking distance is reduced. In addition, for every 100 kilograms of vehicle weight loss, carbon dioxide emissions can be reduced by about 5 grams / km.

B, good processing performance

Polymer materials have very good processing properties. Through the combination of different polymer materials, as well as extrusion, injection molding, calendering, blow molding and other molding processing methods, the automotive polymer materials with various shapes, different properties, different colors and different functions are obtained.

C, excellent comprehensive performance

Polymer materials are versatile and can meet a variety of functional requirements. Through material structure adjustment and modification, the polymer material can have various functions such as heat resistance/cold resistance, rigidity, toughness, cold resistance, corrosion resistance, aging resistance, abrasion resistance and scrub resistance, and waterproofing. Sexual and self-lubricating, good bonding and bonding properties, so it is processed into a variety of automotive interior and exterior parts that are processed into a variety of requirements and functions.

02

Polymer materials are used in automotive lightweighting

The application of polymer materials in automotive lightweighting is mainly divided into three parts: exterior parts, interior parts, and structural parts. The main application of exterior parts: car insurance, roof seals, car finishes, tires, fenders, hoods, hubcaps, etc. The use of exterior parts can be seen in the following picture:

The bumper skins are made of PP/EPDM or PP/elastomer. In addition to modified PP, automotive bumpers are often used in PC/ABS alloys, PC/PBT alloys and SMC materials (a type of FRP made up of unsaturated polyester, fiberglass, etc.), PC/ Bumpers made of PBT are often used in high-end cars.

The lamp is used for lighting and signal, and the lamp material is required to have good light transmission, impact resistance and aging resistance. The lampshade is generally made of PC or plexiglass (PMMA) to ensure good transparency, and the lamp holder is generally made of ABS material.

The exterior mirrors are generally spray-coated, and the materials must have good paint adhesion, heat resistance, aging resistance, and ease of injection molding. The common material of the mirror housing and the base is acrylonitrile-styrene-acrylic rubber copolymer (ASA), which overcomes the shortcomings of long-term weather resistance of ABS resin and yellowing of the color due to sunlight. In addition, modified PP, heat-resistant ABS, PC/ABS can also be used as important materials for rearview mirrors.

Because the air intake grille is close to the engine compartment, it is often affected by high temperature. Generally, it is an electroplated part. The material is favorable for electroplating, good weather resistance, stability, and processing fluidity. PC/ABS, heat-resistant ABS or electroplated ABS is used. ASA, glass fiber reinforced nylon and other materials.

Specific applications for interior components: uprights, car seats, pedals, seat belts, airbag housings, control buttons, and more. The use of polymer materials as interior parts is not only beautiful, but also durable, and the comfort of use is greatly improved.

In addition to the supporting role, the column also acts as a door frame, while the column fascia serves as a decorative effect, plus protection of the internal metal. Materials such as PC/ABS, ASA, acrylonitrile -ethylene propylene diene-styrene (AES) are used.

The instrument panel is divided into a hard instrument panel and a soft instrument panel. The most commonly used material for rigid instrument panels is PP/EPDM/talc. The lower manufacturing cost is generally used in economical models. The soft instrument panel gives a better feel. It is used in medium and high-class cars, and more PCs are used. /ABS/elastomer.

The polymer material used in the seat is mainly used on the coating layer and the seat cushion, and the coating layer mainly includes fabric, artificial leather and leather. The cushion is generally a polyurethane (PU) foam material. In order to improve the comfort of the passenger when it is seated, the seat cushion can be made into a soft and hard composite double seat cushion.

Formed hard tops have gradually replaced soft tops and pasted ceilings. The forming hard top is generally combined with the three layers of the veneer, the foam layer and the base by hot press forming, the surface layer is mostly knitted fabric + foam material, and the base is mostly foamed PU/glass fiber.

The door handle can be PC, ABS, PC/ABS, PC/PBT, PA, etc. Audi, Volkswagen and other interior door handles use electroplated PC/ABS.

03

Development status of polymer materials for automobiles

In developed countries such as Japan, the United States and Europe, the average plastic used in each car has exceeded 260Kg, accounting for more than 17% of the total weight of the car. At present, Toyota, Honda and other auto companies are at the world's leading level in terms of weight reduction, so Japanese cars are the most fuel-efficient. The average plastic consumption per car in China is 150kg, which accounts for about 11% of the total weight. It has reached the level of foreign countries around 2008, so there is still much room for improvement.