| 摘要 |
Multilayer structure based on thermoplastic polymers which is substantially devoid of vinyl chloride polymers and of plasticizers of low molecular mass and which comprises at least 3 layers:a first layer (A) comprising at least 60% by weight of at least one polyolefin of controllable crystallinity defined as comprising at least 90% of ethylene, of propylene or of butene and as having a softening temperature of less than 121° C., the thickness of the first layer being at least 20% of the total thickness of the structure and the first layer having a modulus of elasticity of less than 350 MPa;a second layer (B), positioned between the first layer (A) and the third layer (C), comprising at least 40% by weight of at least one polyolefin of controllable crystallinity, the second layer having an overall softening temperature of less than 121° C.;a third layer (C) comprising at least 50% by weight of at least one polyolefin of controllable crystallinity, the thickness of the third layer being from 5 to 30% of the total thickness of the structure and the third layer having a modulus of elasticity which is less than that of the first layer. |
