Thermoformable transparent packing made of polyester with a lower foil and an upper foil, process for production thereof and use thereof
AssigneeMitsubishi Polyester Film GmbH
InventorsHerbert Peiffer, Martin Jesberger, Stefan Bartsch, Tobias Rentzsch
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Abstract
The present invention relates to a transparent packaging for vacuum forming including a specific biaxially oriented thermoformable polyester foil as lower foil (A) and a specific biaxially oriented polyester foil as upper foil (B) that can be heat-sealed to the lower foil (A), and to a process for the production of such packing, and also use thereof.
Claims13
Transparent packaging for vacuum forming comprising a biaxially oriented thermoformable polyester foil as lower foil (A) and a biaxially oriented polyester foil as upper foil (B) which can be heat-sealed to the lower foil (A),
- wherein
- I. the lower foil (A) comprises at least 85% by weight of a copolyester having dicarboxylic acid components of which from 85 to 94 mol % are terephthalic-acid-derived units and from 6 to 15 mol % are isophthalic-acid-derived units, where the lower foil (A) has the following:
- a) area modulus of elasticity in the range from 4500 to 6400 N/mm2,
- b) total of strength values (σ5 value) in longitudinal direction and in transverse direction in the range from 170 to 220 MPa,
- c) density below 1390 kg/m3,
- d) haze below 2.0% and clarity at least 85% and
- e) thickness in the range from 50 to 300 μm;
- and
- II. the upper foil (B) comprises a base layer (B″) and a heat-sealable outer layer (B′) which can be heat-sealed with respect to lower foil (A), wherein:
- a) the heat-sealable outer layer (B′) comprises at least 90% by weight of a thermoplastic polyester comprised of
- i) from 85 to 97% by weight of amorphous polyester I and
- ii) from 3 to 15% by weight of semicrystalline polyester II,
- c) the heat-sealable outer layer (B′) comprises from 0.04 to 0.35% by weight of inorganic and/or organic particles with median diameter d50 from 1.5 to 5.0 μm, where the ratio of particle size d50 to layer thickness over the outer layer (B′) is greater than 1.0,
- d) the heat-sealable outer layer (B′) has a thickness of from 1.5 to 4.0 μm,
- e) the upper foil (B) has a haze of below 5.0% and a clarity of at least 85%,
- f) the upper foil (B) has a seal seam strength with respect to itself, which is thin sealing, and with respect to the lower foil (A) is in the range from 2 to 7 N/15 mm and
- g) the upper foil (B) has a thickness in the range from 20 to 125 μm.
Biaxially oriented thermoformable polyester foil as lower foil (A) for a transparent packaging comprising at least 85% by weight of a copolyester having dicarboxylic acid components of which from 85 to 94 mol % are terephthalic-acid-derived units and from 6 to 15 mol % are isophthalic-acid-derived units, where the lower foil has the following:
- a) area modulus of elasticity in the range from 4500 to 6400 N/mm2,
- b) total of strength values (σ5 value) in longitudinal direction and in transverse direction in the range from 170 to 220 MPa,
- c) density below 1390 kg/m3,
- d) haze below 2.0% and clarity at least 85% and
- e) thickness in the range from 50 to 300 μm.
Biaxially oriented thermoformable polyester as upper foil (B) for a transparent packaging comprising a base layer (B″) and a heat-sealable outer layer (B′), wherein
- a) the heat-sealable outer layer (B′) comprises at least 90% by weight of a thermoplastic polyester comprised of
- i) from 85 to 97% by weight of amorphous polyester I and
- ii) from 3 to 15% by weight of semicrystalline polyester II,
- c) the heat-sealable outer layer (B′) comprises from 0.04 to 0.35% by weight of inorganic and/or organic particles with median diameter d50 from 1.5 to 5.0 μm, where the ratio of particle size d50 to layer thickness over the outer layer (B′) is greater than 1.0,
- d) the thickness of the outer layer (B′) is from 1.5 to 4.0 μm,
- e) the upper foil (B) has a haze of below 5.0% and a clarity of at least 85%,
- f) the upper foil (B) has a seal seam strength with respect to itself, which is thin sealing, is in the range from 2 to 7 N/15 mm and
- g) the upper foil (B) has a thickness is in the range from 20 to 125 μm.
Dependencies are inferred from the claim text.