Articles with improved optical properties

Patent metadata

Field	Value
Publication number	US-11098141-B2
Application number	US-201616063572-A
Country	US
Kind code	B2
Filing date	Dec 19, 2016
Priority date	Dec 21, 2015
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

Moulded 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.

First claim

The invention claimed is:

1. 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 0.40-0.90 wt % of ethylene and/or a C4-C10 α-olefin determined according to 13 C-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) has a haze of ≤42% (ASTM 1003-D) when measured on 1 mm plaques,
wherein the Ziegler-Natta catalyst is self-supported by being free of any external support material and comprises:
a) compounds of a transition metal of Group 4 to 6 of IUPAC,
b) a Group 2 metal compound,
c) an internal donor, wherein said internal donor is a citraconate,
d) a co-catalyst, and
e) optionally, an external donor.

2. Moulded article according to claim 1 , wherein the at least one α-nucleating agent is either a polymeric nucleating agent and/or a soluble nucleating agent selected from sorbitol derivatives, nonitol derivatives, and benzene-trisamides.

3. Moulded article according to claim 1 , wherein the polypropylene homopolymer:
has a Heat Distortion Temperature (ISO 75B) of at least 90° C.

4. Moulded article according to claim 1 , wherein the polypropylene homopolymer:
has a haze of ≤35% when measured on 1 mm plaques.

5. Moulded article according to claim 1 , wherein the polypropylene homopolymer:
has top load of 360 N or more.

6. Moulded article according to claim 1 , wherein the moulded article is an injection moulded article.

7. Moulded article according to claim 1 , wherein the moulded article has a wall thickness of 2 mm or below.

8. Moulded article according to claim 1 , wherein the moulded article is a container.

Assignees

• Borealis Ag

Inventors

• Wang Jingbo
• Gahleitner Markus
• Klimke Katja
• Braun Juliane
• Leskinen Pauli

Classifications

• C08L2203/10

  used for bottles · CPC title

• C08L2308/00

  Chemical blending or stepwise polymerisation process with the same catalyst · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• C08F2/001

  Multistage polymerisation processes characterised by a change in reactor conditions without deactivating the intermediate polymer (C08F295/00, C08F297/00 take precedence) · CPC title

• C08F2500/12

  Melt flow index or melt flow ratio · CPC title