Long-chain branched polypropylene for film application

Patent metadata

Field	Value
Publication number	US-10457766-B2
Application number	US-201515522622-A
Country	US
Kind code	B2
Filing date	Nov 4, 2015
Priority date	Nov 5, 2014
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

The invention relates to a propylene homopolymer or copolymer having a comonomer in the copolymer selected from ethylene, C4-C20-alpha olefin, said propylene homopolymer or copolymer being free of phthalic compound. It further relates to a long-chain branched propylene homopolymer or copolymer (b-PP) having a comonomer in the copolymer selected from ethylene, C4-C20-alpha olefins, said long-chain branched propylene homopolymer or copolymer (b-PP) being free of phthalic compound. As well as their production processes and uses.

First claim

The invention claimed is:

1. A process for producing a long-chain branched propylene homopolymer or copolymer (b-PP), wherein the process comprises:
producing a propylene homopolymer or copolymer having a comonomer content in the copolymer selected from ethylene, C 4 -C 20 -alpha olefin and any combination thereof, with a comonomer content in the range of 0.1 to 7.0 wt %, in a polymerization process in the presence of a catalyst system comprising:
(a) a Ziegler-Natta based catalyst with a transition metal of Group 4 to 6 (TM), the catalyst containing an internal donor,
(b) optionally a co-catalyst (Co),
(c) optionally an external donor (ED) and wherein if present, the co-catalyst (Co) to external donor (ED) molar ratio [Co/ED] is in the range of 3.0 to 45.0 mol/mol and wherein the co-catalyst (Co) to transition metal of Group 4 to 6 (TM) molar ratio [Co/TM] is in the range of 40.0 to 500 mol/mol;

wherein the resulting propylene homopolymer or copolymer powder has:
(a) a porosity of more than 8.0%,
(b) a median particle size d50 in the range of 150 to 1500 μm, and
(c) a top-cut particle size d95 in the range of 500 to 400 μm,

wherein the internal donor comprised in the Ziegler-Natta catalyst (a) is a non-phthalic compound; and
mixing said propylene homopolymer or copolymer with a thermally decomposing free radical-forming agent and optionally with at least one functionally unsaturated compound at a temperature of 20 to 100° C. for at least 2 minutes to form a pre-mixed material and melt mixing the premixed material in a melt mixing device at a barrel temperature in the range of 180 to 300° C. to obtain said long-chain branched propylene homopolymer or copolymer (b-PP), wherein the long-chain branched propylene homopolymer or copolymer (b-PP) has:
(a) a comonomer in the copolymer selected from ethylene, C 4 -C 20 -alpha olefin and any combination thereof and a comonomer content in the range of 0.1 to 7.0 wt %,
(b) the melt flow rate MFR 2 (230° C.) of the b-PP is in the range of 6.5 to 25.0 g/10 min as measured according to ISO 1133,
(c) the F30 melt strength of the b-PP is in the range of 5.0 to 12.0 cN wherein the F30 melt strength of the b-PP is measured according to ISO 16790:2005,
(d) the xylene hot insoluble (XHU) fraction of the b-PP is less than 0.08 wt % as measured according to EN 579, and
(e) the b-PP is free of phthalic compound.

2. Process according to claim 1 , wherein the long-chain branched propylene homopolymer or copolymer (b-PP) has a v30-A melt extensibility of equal to or more than 200 mm/s wherein the v30 melt extensibility is measured according to ISO 16790:2005.

3. Process according to claim 1 , wherein the non-phthalic compound is selected from (di)esters of non-phthalic carboxylic (di)acids wherein the (di)ester belongs to the group comprising malonates, maleates, succinates, citraconates, glutarates, cyclohexene-1,2-dicarboxylates and benzoates and derivatives of any of them and/or mixtures of any of them.

4. The process according to claim 1 , further comprising the step:
mixing the long chain-chain branched propylene homopolymer or copolymer (b-PP) with at least one or more compounds chosen from:
(a) additives,
(b) polymers,
(c) fillers,
(d) reinforcement agents, and
(e) any combination of (a), (b), (c), and (d),

for producing a long-chain branch polypropylene composition (b-PP-c).

5. The process according to claim 4 , wherein the long-chain branch polypropylene composition (b-PP-c) has:
(a) a melt flow rate MFR 2 (230°C.) in the range of 6.5 to 25.0 g/10min as measured according to ISO 1133,
(b) an F30 melt strength in the range of 5.0 to 12.0 cN, wherein the F30 melt strength is measured according to ISO 16790:2005,
(c) a xylene hot insoluble (XHU) of less than 0.08 wt % as measured according to EN 579,
(d) an OCS value of less than 2000, and measured according to the method described herein, and
(e) the long-chain branched polypropylene composition (b-PP-C) is free of phthalic compound.

Assignees

• Borealis Ag

Inventors

• Braun Hermann
• Wang Jingbo
• Gahleitner Markus
• Prokschi Hermann
• Lilja Johanna

Classifications

• C08F255/04

  on to ethylene-propylene copolymers {(C08F255/023 takes precedence)} · CPC title

• C08L23/10

  Homopolymers or copolymers of propene · CPC title

• C08F4/651

  Pretreating with non-metals or metal-free compounds · CPC title

• C08F4/6546

  organo-magnesium compounds · CPC title

• C08F4/6492

  containing aliphatic unsaturation · CPC title