Why Carbon Fiber Filling Is Rarely Used in PP Color Film Modification for Automotive Interiors

PP color film is widely used in automotive interiors—for covering parts like dashboard trims, door panels, or center console surfaces—because it is cheap, flexible, and easy to color. However, when modifying this PP color film to improve its performance, carbon fiber filling is rarely chosen. There are four key reasons for this, all closely tied to the special needs of automotive interior materials.​

1. High Cost Makes It Unfit for Mass-Produced Car Interiors​

Carbon fiber is much more expensive than common fillers (like talc or calcium carbonate) used in PP film modification. Its production process—from making carbon fiber strands to processing them into fine fillers—involves complex steps and high energy consumption, which pushes up its price. Automotive interiors require large amounts of PP color film, and using carbon fiber would significantly increase the overall cost of car production. For most mass-produced cars (not luxury or high-performance models), cost control is critical. Choosing cheaper fillers can meet basic performance needs (like stiffness or wear resistance) without raising prices, making carbon fiber an uneconomical choice.​

2. Poor Compatibility and Difficult Processing​

Carbon fiber has poor compatibility with PP resin—the base material of PP color film. To mix them well, manufacturers need to use special surface treatments (like coating the carbon fiber with chemicals) to help it bond with PP molecules. This extra step adds time and cost to the production process. Worse, carbon fiber is rigid and has a rough surface. When mixed into PP resin, it can reduce the resin’s flowability—the ability to melt and spread evenly during film-making. This makes it harder to produce thin, smooth PP color films. For automotive interiors, where film surfaces need to be soft and even (to avoid scratching hands or looking uneven), this processing difficulty is a big problem.​

3. It Hurts the “Touch and Feel” Required for Car Interiors​

Automotive interiors have strict requirements for “tactile comfort”—how the material feels when touched. Pure PP color film is soft and slightly flexible, which matches the cozy, user-friendly feel needed for parts like door handles or dashboard trims. But carbon fiber is stiff and brittle. When added as a filler, it makes the PP film harder and less flexible. Touching a carbon fiber-filled PP film would feel rough or rigid, which goes against the comfortable experience car makers want to provide. For example, if a door panel uses this modified film, passengers might feel uncomfortable when leaning against it. This “bad touch” alone makes carbon fiber a poor choice for interior PP films.​

4. It Risks Fading and Surface Damage​

Car interiors are exposed to sunlight (through windows) and daily friction (like hands brushing against trims) for a long time. Carbon fiber has poor weather resistance—it can fade or lose strength when exposed to UV rays from the sun. Over time, a carbon fiber-filled PP color film on the dashboard might turn dull or even crack. What’s more, carbon fiber’s rough texture can make the film’s surface more prone to scratches. For automotive interiors, which need to stay looking new for years, this lack of durability (against sun and scratches) is a major downside. Cheaper fillers like talc, by contrast, don’t affect the film’s weather resistance or surface smoothness as much.​

In short, carbon fiber filling fails to meet the key needs of automotive interior PP color films: low cost, easy processing, comfortable touch, and long-term durability. For car makers, choosing other fillers (like talc or glass fiber) is a more practical way to modify PP color films—they improve performance without sacrificing the qualities that matter most for interior use.​