In-situ formation of low density thermoplastic polyurethane flexible foams
AssigneeHuntsman International LLC
InventorsJan Vandenbroeck, Steve Andre Woutters, Rajesh Kumar Gajendran, Martino Dossi, Rene Alexander Klein, Mark Joseph Brennan
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Abstract
A reactive mixture and method for making a thermoplastic polyurethane (TPU) flexible foam having a predominantly open-cell structure (open-cell content of ≥50% by volume calculated on the total volume of the foam and measured according to ASTM D6226-10) and an apparent density below 200 kg/m3.
Claims16
An in-situ method for making a thermoplastic polyurethane (TPU) flexible foam having (i) an open-cell content of ≥50% by volume calculated on the total volume of the foam and measured according to ASTM D6226-10, (ii) a density below 200 kg/m3, measured according to ISO 845, (iii) a hardblock content in the range 15 up to 65%, and (iv) a trousers tear strength>100 N/m measured according to DIN 53356, said method comprising combining at an isocyanate index between 90 and 110 in situ at least following ingredients to form a reactive mixture:
- a) a polyisocyanate composition comprising at least 90% by weight difunctional isocyanate compounds calculated on the total weight of all isocyanate compounds in the polyisocyanate composition,
- b) an isocyanate reactive composition comprising at least 90 wt % difunctional isocyanate reactive compounds calculated on the total weight of all isocyanate reactive compounds in the isocyanate reactive composition and wherein said difunctional isocyanate reactive compounds are selected from at least one linear high molecular weight difunctional polyol having a molecular weight in the range 500-20000 g/mol and at least one low molecular weight difunctional chain extender having a molecular weight<500 g/mol,
- c) at least one polyurethane forming catalysts,
- d) a blowing agent composition wherein at least 90 wt % of the blowing agents are selected from physical blowing agents and/or non-reactive chemical blowing agents having no isocyanate reactive groups, wherein the amount of blowing agents is from 5 to 60 parts by weight per hundred weight parts isocyanate reactive compounds,
- e) at least one compound acting as a surfactant, and
- f) optionally further additives
- and wherein the reactive mixture contains less than 0.1 wt % water calculated on the total weight of the reactive mixture and wherein said in-situ method is selected from a moulding process, a free-rise spray process or a free-rise slabstock process.
Dependencies are inferred from the claim text.