Polychlorinated ester materials are more and more widely used in the automobile industry, and have become one of the most widely used plastics in automobiles. The global automobile manufacturing industry uses more than 1 million tons of polyurethane every year. In 2006, the annual output of China's automobile industry will exceed 7.2 million vehicles, and the total consumption of polyurethane will reach more than 100000 tons. Polyurethane generally accounts for 15% of the plastic used in vehicles. The average usage of each vehicle is 15 kg, and most of them are MDI series products.

According to different automobile components, polyurethane foam Plastics, elastomers, adhesives and other different forms and properties to meet different requirements. For example, with the change of formula, polyurethane foam has the characteristics of light weight, heat insulation, good resilience, good comfort, good low-temperature performance, durability, safety and vibration absorption. Its advantages are unmatched by other materials.

The recycling of waste foamed plastics from automobiles and household appliances has attracted more and more attention. Recently, foreign automobile manufacturers have been able to recycle 30% of the waste foamed plastics. The production process is to clean, crush and dry the waste foamed plastics, and finally stick these waste foamed plastics together with adhesives, which can be used to produce carpet backing and other padding materials.

(1) Skin material

At present, automobile manufacturers are pursuing to further improve the comfort, safety and beauty of the interior space in terms of automobile interiors. It can be said that automobile interiors are increasingly developing towards advanced direction. This advancement is first reflected in the use of a variety of materials with different properties (fiber fabrics Leatherwear , wool planting), so as to make all surfaces in the car soft and beautiful (deep and thick patterns, wood grain, color matching). Soft decorative surface materials, internal sound absorption, vibration absorption materials and skeleton materials are combined to form the interior ceiling, luxury instrument panel, steering wheel, seat, etc. In fact, this development is in contradiction with material recycling and cost reduction. Therefore, the development of interior decoration can not only meet the requirements of advanced, soft and personalized interior decoration, but also meet the requirements of lightweight, low-cost and material recycling New materials It is a top priority.

BASF Company has developed a polyurethane elastomer skin material (TPU) Elastoskin for automobile interior decoration, which is used for the surface of instrument panel and door panel interior trim. Its performance is better than PVC and other skin materials currently used, and its cost is lower than PVC and other skin materials. It is an ideal substitute for PVC. The material has excellent mechanical properties, very good leather grain feel, flexibility and luxury, and can be used for two-color products; Its excellent durability (weather resistance, high and low temperature resistance, scratch resistance) makes it the first choice for high-quality C-class car interior trim skin materials. This material has been used in the instrument panel and door inner panel of Bujck Park Avenue, OIdsmobiie Aurora, Cadillac CTS and other cars, and will also be used in new models such as Cadillac Seville and Cadillac Deville. In short, the application of this material in automotive interior parts has just begun. The greater significance of using aromatic polyurethane spray molding skin is that it provides an effective way for the production of polyurethane integrated (polyurethane spray skin+low-density polyurethane buffer foam+polyurethane chopped fiber skeleton) recyclable dashboard.

In addition, Bayer's thermoplastic polyurethane adopts the blow molding process for automobile dashboard and door panel. It is said that this process can save 70% of the time than casting.

(2) Dashboard buffer

The outer surface of the instrument panel is vacuum formed, filled with semi-rigid polyurethane foam plastic in the middle, and fixed with the metal or plastic framework. Semi rigid polyurethane foam is characterized by high compression load and outstanding shock absorption performance, which is very suitable for manufacturing protective cushion materials for automobile dashboard, handrail, door pillar and other parts.

(3) Skeleton material

A polychloroester structural reaction molding (SRlM) technology has been widely used in Europe and the United States, which can effectively reduce the quality of parts. The process is as follows: first, preform the skin, put the glass fiber mat into the mold, and then inject the polychloride resin, and cure it (micro foaming). This process can be used to produce a variety of automotive trim parts, such as door trim panel, coat rack, instrument panel framework and ceiling framework. The advantage of SRIM is that it can flexibly design wall thickness, radian or stiffener according to different mechanical properties of parts. Compared with injection molding and other products, SRIM has a lower interior noise and can improve the physical properties of the product, such as lower density, higher elongation, less odor and mildew, which can create a comfortable interior environment.

The existing production technology of door panels in China is to put glass fiber into the mold in advance, then inject the composite material, and mold the required automotive dashboard, door panel, air conditioning cover and other interior trim parts after mold closing. Another technology is short cut glass fiber spray molding.

The polyurethane products formed by RIM and RRIM technology are mainly used for steering wheel, bumper body Wall panel engine Cover, trunk lid, radiator grille, mudguard, spoiler, etc. The quality of RRIM products is only 55% of steel, but the surface quality and dimensional stability of parts need to be further improved, and the amount of RRIM products is not very large.

The seat cushion, backrest and headrest are the parts where polyurethane foam plastic is widely used in automobiles, and are also the most sensitive places for people's riding comfort. Therefore, the performance requirements for products are also very strict. At present, most of the polyurethane foam seat cushions used in domestic automobiles are cold cured products with uniform density. The new automobile seat cushion developed in recent years uses dual hardness or multi hardness foam. The production of this dual hardness seat cushion can be realized by using polyether polyol and isocyanate through double head or multi head mixing head injection mold, or full MDI cold molding process. The hardness of different parts of the seat cushion can be accurately controlled by changing the isocyanate index - the middle of the seat cushion is soft Both sides are hard. Soft foam gives people comfort. The hard parts on both sides provide support. When the car runs at high speed or turns, it helps to maintain the stability of the driver and passengers and improve the safety of riding. FAW Group Fu'ao Company has produced dual hardness and multi hardness foams with 3-component mixing technology, which is in a leading position in China.

The structure of the handrail is that there is a steel framework in the middle and the door panel is fixed, and the outer layer is covered with self skinning semi-rigid polyurethane foam. The surface has decorative patterns, which makes people feel comfortable and safe when riding. There are also hand rests on the left and right door inner guards of the car, which are made of self skinning semi-rigid polyurethane foam, and plastic lining skin filled with foam plastic structure. The material used in this part shall be sweat resistant, odorless, hardness index, high and low temperature performance, etc.

The steering wheels of passenger cars in China are basically made of semi-rigid self skinning polyurethane foam as the outer covering layer, and the inner part is welded from the steel skeleton, which has gradually turned to aluminum magnesium alloy Integral die casting. The hardness of the coating is generally Shore A60-80 。

(1) Car roof, door inner panel

The interior ceiling is a product formed by composite processing of various materials, which requires multiple functions such as heat insulation, sound absorption, sound insulation, vibration absorption, etc. The soft ceiling is made of polyurethane foam plastic composite fiber fabric, non-woven fabric, artificial leather and other materials, while the hard ceiling is made of fabric fiber, glass fiber, cardboard and polyurethane foam through laminated pressing.

There are also many places where polyurethane foam plastic sheets are used in cars, such as seats Fabric At present, textile+PU+knitting synthetic fiber is widely used. After the top interior is compounded with PVC film and PU, small holes are punched on its surface, and then pasted in the cab roof with adhesive.

PP and PPO are often used as the materials of door column trim panel. Considering the material cost, PP materials with high fluidity, high rigidity and good impact resistance will have certain advantages in the future. The surface color of the door pillar trim panel must match the overall color of the car, and it is required to be anti-static, scratch resistant and beautiful. Therefore, the development of the production technology of integrated vacuum forming or hot pressing of propylene sheet and surface decoration materials can meet the needs of car production with small batch.

(2) Polyurethane foam for sealing

There are some rectangular soft polyurethane foam sealing blocks in the heating and air conditioning system, instrument panel assembly, electrical parts or other parts of the car. Cavity foam casting of A and B pillars of the car body, some of which use damping expansion film to reduce the vibration and noise of the car body.

Microporous polyurethane foam is expected to replace rubber materials in most car bodies as shock absorbers for underbody. North American automobile manufacturers are working hard to make cars more quiet and comfortable. The damping pad is installed on the chassis of the vehicle to isolate the vehicle body from the frame, so as to improve the riding and driving quality. Microporous polyurethane is a unique innovative material for sound insulation and vibration attenuation (NVH).

As a substitute for rubber car body assembly, microporous polychloroester has competitive price. It can effectively improve the damping performance, extend the material performance retention time, reduce the mass, and improve the assembly process. Another advantage of using microporous polyurethane is that by changing the material density, it is easy to optimize the anti vibration rubber pad of the car body chassis, rather than having to adjust it by changing the material production formula or product geometry as in the traditional process. The latter requires prototyping, which is costly and time-consuming.

The composite structure of low foamed PVC material+PU foamed material+porous material is mostly used in light buses. The low foamed PVC material is shaped by vacuum suction, filled with foamed PU material locally, and pasted with porous material locally on the back. The structure is both elastic and solid, and has good foot sensibility, sound insulation and heat insulation performance.

In order to effectively ensure the sound insulation and heat insulation effect of the interior of the body, in addition to the use of rigid polyurethane foam for the thermal insulation layer in the middle of the refrigerator car, the van van also uses on-site foam spraying to expand the application of rigid polyurethane foam - spraying rigid polyurethane foam on the top and inside of both sides of the body The outer skin is bonded into an organic whole. So as to effectively improve the heat insulation, heat preservation and sealing performance of the car body, prevent the corrosion of the car body, reduce the vibration of the car body, and reduce the noise inside the car. The estimated consumption of each vehicle is about 20 kg.

The engine heat shield made of rigid polyurethane foam plastic is made of polyurethane foam, glass fiber felt, nylon fabric layer or aluminum film, which is characterized by light weight and good heat insulation.

The application of glass fiber reinforced polyurethane foam plastic in automobile parts is also gradually expanding, for example, the parts used in the automobile integral roof interior decoration are made of textile and glass fiber reinforced PU. For another example, the wheel cover mudguard, oil pan mudguard and other products are light and thin, with complex shapes, which require high process requirements, as well as stone splash resistance, impact resistance and high and low temperature performance.

Recently, many automotive interior trim parts have shown the development trend of replacing polyurethane (PUR) materials with polyolefin (PO) foam plastics. Several polyolefin foam plastics are constantly challenging the application of polyurethane foam plastics in many aspects, including the surface layer of automotive interior trim parts, foam, coated fiber, fabric and sound insulation system. The driving force behind the replacement of polyurethane foam with foamed polyolefin lies in the product cost, the recyclability of the product, and whether it can reduce the emission of toxic gas, because toxic gas will be generated in the process of PUR foam heating the laminated fabric.

The automobile dashboard has many functions, many parts and complex structure recycling The dashboard should be considered first. The current dashboard is mostly composed of PVC skin+semi hard foamed PU+skeleton, so it is very difficult to recycle the materials. The development trend of the dashboard is that it is easy to disassemble and assemble in design, meet the design requirements in material selection, and consider the possibility of recycling, so as to be beautiful and low-cost. This is likely to promote the development of thermoplastic instrument panels and single variety plastic instrument panels, but it should meet the requirements of safety and aesthetics.

The interior ceiling of a car is generally formed by glass fiber+foamed polychlorinated ester+surface decorative fabric, and the truck is generally made of foam sheet with artificial leather or fiber fabric on the surface. Considering the function and recycling requirements, the future development trend is that the skeleton, sound absorption, heat insulation and skin materials should be the same material as far as possible, or the reinforcement that can be directly recycled without separation should be used compound material 。

PU leather gradually replaces PVC artificial leather. As the first generation of artificial leather products, PVC artificial leather has developed to a large scale since the 1970s with its characteristics of similar natural leather, bright appearance, soft texture, abrasion resistance, folding resistance, acid and alkali resistance. However, due to poor air permeability and moisture absorption, the development in recent years has been limited. At present, PU can be a substitute for PVC wherever it is used. PU not only has excellent strength and toughness, but also is aging resistant, breathable, moisture permeable, water impermeable and oil resistant. It is a mature environmental protection material.

FAW Group Fu'ao Johnson Co., Ltd. is the backbone factory in the automotive interior products industry. Every year, more than 10000 tons of polyurethane raw materials are used for softening products such as seats and instrument panels, and 4000 tons are used in Changchun alone. There are more than 100 kinds of softened products such as seats and instrument panels for Jetta, Audi, Mazda and Jiefang Auto, and more than 3000 tons of polyurethane raw materials are consumed every year.

The technical problems existing in the polyurethane foam and products mainly include: the storage stability of MDI, TDI and additive mixture, the damp heat aging resistance of the product, the product cavitation, cracking and other defects due to the unstable foaming process.

The development needs of polyurethane foam and products mainly include: lightweight, multi hardness, low odor, low haze, aging resistance, storage stability, environmental protection, such as the replacement of foaming agent.