HMS PP foam sheet with good compressive strength and recoverability
AssigneeBorealis AG
InventorsAntti Tynys, Norbert Reichelt, Yi An Lin
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Abstract
The present invention relates to a foamed sheet consisting of a polypropylene composition comprising at least 85 wt. %, e.g. from 85 to 99.5 wt.-%, of a high melt strength polypropylene (HMS-PP) and 0.5 to 15 wt. % of a nucleating agent (NA), wherein the foamed sheet has a thickness of below 0.5 mm or a thickness of 2.0 mm or more. The present invention further relates to a foamed material consisting of a polypropylene composition as well as the use of a polypropylene composition comprising at least 85 wt. %, e.g. from 85 to 99.5 wt.-%, of a high melt strength polypropylene (HMS-PP) and 0.5 to 15 wt. % of a nucleating agent (NA) for producing foamed material.
Claims9
A foamed sheet consisting of a polypropylene composition comprising 85 to 95 wt. %, of a high melt strength polypropylene (HMS-PP) and 5.0 to 15 wt. % of a nucleating agent (NA), the foamed sheet having a thickness of 2.0 to 7.0 and a density from 75 to 325 kg/m3.
A foamed material consisting of a polypropylene composition, wherein the polypropylene composition comprises 85 to 95% wt. % of a high melt strength polypropylene (HMS-PP) and 5.0 to 15.0 wt. % of a nucleating agent (NA), wherein the foamed material is in the form of a foamed sheet having a thickness of 2.0 to 7.0 mm and a density from 75 to 325 kg/m3 and the foamed material fulfills the following relationships (I) and (II):
- Compressive strength at 25% compression/(foam density)2>0.018 kPa/(kg/m3)2 (I)
- wherein,
- compressive strength at 25% is the compressive strength determined according to IS03386-1 at 25% without pre-compression cycles [0], in kPa
- foam density is the density of the foam determined according to ISO 845, in kg/m3;
- Compressive strength at 40%/(foam density)2>0.020 kPa/(kg/m3)2 (II)
- wherein,
- compressive strength at 40% is the compressive strength determined according to IS03386-1 at 40% without pre-compression cycles [0], in kPa
- foam density is the density of the foam determined according to ISO 845, in kg/m3,
- and further having a recoverability determined according to the method specified in the examples herein of at least 85%.
Dependencies are inferred from the claim text.