With the rapid advancement of technology, the automotive industry is entering a period of significant transformation. As consumers' demands for interior space continue to rise, the comfort, safety, and high-quality performance of automotive interiors are gaining significant attention. Automotive interior plastic products primarily include instrument panels, seats, headliners, door panels, center consoles, armrests, carpets, trunk linings, engine hood linings, and various felt mats for sound absorption and noise reduction. The following introduces several representative automotive interior plastic products and the materials used to make them.
●Instrument Panels
Currently, automotive instrument panels can be categorized as rigid and flexible. Rigid instrument panels are typically used in light and small trucks and are injection molded in a single step. These panels are large and unclad, requiring extremely high surface quality, high-temperature resistance, and rigidity. Materials available include modified resins, PPO, ABS, and filled PP.
Flexible instrument panels consist of a surface covering, a frame, and cushioning material. General-end sedans, such as the FAW Jetta and Shanghai Santana, use PVC/ABS sheet vacuum-formed instrument panel skins; mid-range and high-end sedans, such as the FAW Audi and Hongqi, use powdered PVC slush-molded instrument panel skins.
To facilitate recycling, instrument panels constructed from thermoplastic polyolefin (TPO) skins, modified polypropylene frames, and polypropylene foam are being developed. Furthermore, with the introduction of airbags, soft-trim instrument panels have lost their safety benefits. Therefore, as long as the appearance quality is maintained, a low-cost, rigid instrument panel is entirely feasible.
●Seats
Currently, seat cushioning is primarily made of soft, highly resilient polyurethane foam, with metal frames. Overseas, all-plastic seats are being developed that, in addition to the cushioning, also use long glass fiber-reinforced polypropylene or 30% glass fiber-reinforced PA6 for the seat frames, reducing weight by over 40% and cost by approximately 15%.
●Door Inner Panels
The door inner panel's structure is similar to that of the instrument panel, consisting of a frame, foam, and skin. Door inner panels are typically made from hardboard or PP wood powder plastic sheets, then laminated or compounded with a polyurethane lining and PVC film or non-woven fabric. Modified PP or ABS can also be used to create the door inner panel frame, which is then compounded with soft trim materials to create a single door inner panel.
For example, in the Red Flag and Audi sedans, the door inner panel frame is injection-molded from ABS, and a knitted polyester skin lined with PU foam is vacuum-formed onto the frame to create a single piece. Furthermore, some trucks even use door inner panels with a layer of PVC artificial leather applied directly to them.
●Ceilings
Ceilings are a composite laminate product with the most diverse material combinations among vehicle interior components. Besides its primary decorative function, they also provide various special functions, such as thermal insulation, sound insulation, and sound absorption. Roofing types can be categorized as formed (formed roofs secured by inlay bonding), adhesive-bonded (foam pads with a cover are directly bonded to the interior of the vehicle roof), and suspended roofs. Formed roofs account for over 70% of all roofing types, with adhesive-bonded roofs often used for truck cabs and vans.
Formed roofing consists of a base material and a cover. The base material requires lightweight, high rigidity, dimensional stability, and ease of forming. Therefore, thermoplastic PU foam sheet, PP foam sheet, fiberglass, corrugated paper, honeycomb plastic tape, and other materials are commonly used. The cover material can be fabric, non-woven fabric, or PVC. In my country, passenger car roofs are typically laminated using thermoplastic PU foam sheet, fiberglass, and non-woven polyester fabric.
●Carpets
Carpet materials must be crisp, soundproof, and comfortable, avoiding sagging and wrinkling. Therefore, rubber-based synthetic fiber needle-punched felt or PVC low-foam is commonly used.
●Others
Door pillar covers, glove boxes, hoppers, air conditioning housings, various ducts, and air grilles are primarily made of ABS and polyolefin plastics.