Biaxially oriented polypropylene film having more than one layer, its use, and process for its production
AssigneeMitsubishi Polyester Film GmbH
InventorsHerbert Peiffer, Gottfried Hilkert
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Abstract
The invention relates to a biaxially oriented polypropylene film which has very good optical properties and good processing performance and which, after it has been metallized or has been coated with oxidic materials, has a high oxygen barrier value, and whose structure has at least one base layer B and at least one layer A applied to this base layer, where this layer A has a specified number of elevations of specified height and specified diameter. The invention further relates to the use of the film and to a process for its production.
Claims21
A biaxially oriented, coextruded polypropylene film comprising:
- (A) a base layer B, at least 80% by weight of which is composed of thermoplastic polypropylene;
- and
- (B) one or more additional layers,
- wherein at least one outward-facing layer A has a number of elevations/protrusions N per mm2 of film surface area which is related to their respective heights h and diameters d by the following equations
- log N/mm2<Ah−Bh*log h/μm, 0.05 μm<h<1.0 μm (1)
- Ah=1.4;
- Bh=2.5
- log N/mm2<Ad−Bd*log d/μm, 0.2 μm<d<10 μm (2)
- Ad=3.4;
- Bd=2.4
Dependencies are inferred from the claim text.