Choosing Among Mineral-Filled PP Grades: Where T10, TD20 and TD30 Separate

A typical curve

As loading rises from zero to 40%: flexural modulus climbs nearly linearly; tensile strength peaks around 20-30% then falls back; notched impact declines steadily from TD10 and at TD40 often reaches less than half that of homopolymer PP.

TD20 became the workhorse grade because it balances stiffness gain against retained impact, not because it leads on any single property.

Selecting a tier

TD10: when low density with some stiffness gain matters, typically thick-walled interior parts carrying no impact load.

TD20: the best all-round balance, covering most automotive interiors and appliance structures.

TD30 / TD40: only where stiffness and heat resistance dominate and brittleness is acceptable, such as parts needing extreme dimensional stability. Expect worse surface finish, poorer paintability and difficult screw assembly.

Talc quality is overlooked

Mesh size, purity and surface treatment of the talc can matter more than loading. Fine grades above about 3000 mesh with stearic acid or silane treatment deliver better retained impact at equal loading.

That is one of the main reasons nominally identical grades differ noticeably between suppliers.