Articles with improved optical properties
AssigneeBorealis AG
InventorsJingbo Wang, Markus Gahleitner, Katja Klimke, Juliane Braun, Pauli Leskinen
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Abstract
Molded articles comprising a polypropylene homopolymer with rather high melt flow rate, high stiffness, improved optical properties and an advantageous balance between stiffness and optical properties.
Claims13
Moulded article comprising a polypropylene homopolymer, wherein the polypropylene homopolymer is polymerised in the presence of a Ziegler-Natta catalyst and wherein the polypropylene homopolymer:
- a) comprises 0-1.0 wt % of ethylene and/or a C4-C10 α-olefin determined according to 13C-NMR,
- b) comprises at least one α-nucleating agent,
- c) is free of phthalic acid esters as well as their respective decomposition products,
- d) has a MFR230/2.16 determined according to ISO1133 in the range of 20-200 g/10 min, and
- e) a haze of ≤45% (ASTM 1003-D) when measured on 1 mm plaques.
Method for producing moulded articles with improved Heat Distortion Temperature and/or optical properties comprising the steps of:
- a) polymerising propylene and optionally ethylene in the presence of a Ziegler-Natta catalyst, wherein the Ziegler-Natta-catalyst comprises:
- i. compounds of a transition metal of Group 4 to 6 of IUPAC,
- ii. a Group 2 metal compound (MC), and
- iii. an internal donor (ID), wherein said internal donor (ID) is a non-phthalic compound,
- iv. a co-catalyst (Co), and
- v. optionally an external donor (ED)
- b) optionally incorporating at least one α-nucleating agent
- c) moulding articles comprising said polymer obtained in step a to b).
Method according to any claim 12, wherein the α-nucleating agent incorporating in step b) is a polymeric nucleating agent and/or a soluble nucleating agent.
(canceled)
Dependencies are inferred from the claim text.