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Sofpur lightweight and aesthetic TPU

Sofpur ® (TPU)

Elastomer-modified TPU
Sofpur® is an innovative material which has been developed by SO.F.TER. for the footwear industry. It is an elastomer-modified Thermoplastic Polyurethane (TPU) which combines in one single product the excellent mechanical characteristics of Polyurethane - particularly an excellent abrasion resistance - with the processing ease typical of Thermoplastic Elastomers. Sofpur®, in fact, can be easily transformed with the same machines used for the injection-molding of TPR (Thermoplastic Rubber).

 

Sofpur® looks exactly like vulcanised rubber, but, unlike it, Sofpur® does not require any dedicated technology neither a long and expensive transforming process, and it is also fully recyclable. Thanks to its excellent aesthetical properties it is particularly suitable for high fashion and leisure shoes. Its weight, 10% lower than a TPU, and its high resistance to abrasion make it suitable for sports, technical and professional shoes.

 

RANGE

The Sofpur® range also includes the Light series, whose weight is 35% lower than standard Sofpur® and more than 40% lower than standard TPU. Sofpur® Light is recommended for the soles and insoles of trekking, sports and outdoor shoes, and it is also suitable for fashion footwear with thick soles.

 

WEIGHT

TPU - weight (gr/cm3) 1.18-1.20

Sofpur® - weight (gr/cm3) 1.07-1.09

Sofpur® Light - weight (gr/cm3) 0.65-0.70

 

CUSTOMIZATION SERVICE

SO.F.TER. provides its clients with a quick service of customization and development of new tailor-made materials, thus allowing them to satisfy any specific marketing need.
The Sofpur® range features the following characteristics:
  • Available in hardness that ranges from 60 ShA to 80 ShA
  • Lightness (10% less weight than standard TPU)
  • Excellent abrasion resistance
  • High elastic recovery at low temperatures
  • Compatible with bi-component Polyurethane
  • Possibility of direct injection-molding on leather and hide
  • Easily processable with traditional TPR machines
  • Excellent colourability, available in a wide range of classical and fashion colours
  • Excellent aesthetical properties; it enhances the matt/glossy contrast
Thanks to its aesthetical properties Sofpur® is particularly suitable for high fashion and leisure shoes.
Its lightness and excellent abrasion resistance make it suitable for sports, technical and professional shoes.
Sofpur® Light is recommended for soles and insoles of trekking, sports and outdoor shoes.
Sofpur® is normally transformed by injection-molding machines. The injection process can be carried out by simple screw type, controrotating screw type or transfer type machines.

PLASTICIZING SCREW: screws having L/D ratio ≥ 20 L/D are the most suitable
PLASTICIZING SPEED: medium
INJECTION SPEED: medium-high
INJECTION PRESSURE: medium
RUNNERS: it is advisable to use the shortest possible runners, with a circular section and a gradually decreasing flow-through diameter.
INJECTION POINTS: usually having a circular section and diameter >2 mm. For Sofpur Light a diameter of 6-8 mm. is recommended
AIR VENTS: appropriate air vents from the cavities should be taken into account (diameter 0,03 - 0,05 mm)
SHRINKAGE: having a TPU matrix, Sofpur can undergo some shrinkage which can vary from 0,4% to 1,2% depending on material hardness and type.
DRYING: usually not necessary

INDICATIVE MOULDING TEMPERATURES: the following moulding temperatures are purely indicative; they are to be adjusted according to equipment used.
SOFPUR®
Feeding zone 135-145°C | Average moulding temperature 140-150°C | Nozzle 15-20°C
SOFPUR L®
Feeding zone 165-175°C | Average moulding temperature 170-180°C | Nozzle 15-20°C
SOFPUR LE®
Feeding zone 165-175°C | Average moulding temperature 170-180°C | Nozzle 15-20°C
SOFPUR LIGHT®
Feeding zone 120-130°C | Average moulding temperature 130-140°C | Nozzle 15-20°C
SOFPUR S®
Feeding zone 145-155°C | Average moulding temperature 150-160°C | Nozzle 15-20°C
Sofpur® is a fully recyclable material and it can be reused after regrinding. The user shall always verify that the compound obtained by mixing virgin and reground material is suitable for the specific application and that its properties meet the requirements.
This product should be stored in a covered facility and kept away from moisture and heat.
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