Why Use PU
Castable polyurethanes or PU are a general term that is used for a wide range of polymers. But they are specifically high molecular weight polymers which are based on Isocyanate chemistry. All Urethanes are produced with a reaction between 3 components:
- A Polyol (PPG, PTMEG and Polyester)
- An Isocyanate (TDI, MDI, NDI)
- A cross-linker / Chain extender (Diamine, Diol and Triols)
In general the Polyol and Isocyanate parts are pre-blended liquids called Pre-polymers. This is then hand or machine blended with the cross linker, poured into a mould and cured to produce the end component. There are many different families of polyurethanes, for example; Castable Elastomers, Rigid and Flexible foam, Adhesives, Sealants & Coatings.
Watts Urethane Products specialise in manufacturing castable polyurethane products, which are true engineering materials. Castable polyurethanes are true elastomers, the definition of which is a material that can be extended to at least twice its length and then return to its original form.
The major characteristic of these polyurethanes are their extraordinary physical properties and the variety of strengths that are available between the different families of urethanes. There are two main reasons for using polyurethanes; their physical performance and their cost effectiveness. Below is a chart detailing the advantages of using Urethanes over other materials.
Castable Polyurethane advantages over other materials
|Urethane Vs Metal||Urethane Vs Rubber||Urethane Vs Plastic|
|Abrasion Resistance||Abrasion resistance||Impact resistance|
|Impact resistance||Higher Load Bearing||Elastic Memory|
|Easily Mouldable||Greater range of hardness’s||Thick section moulding|
|Noise reduction||Clarity and colourability||Resilience|
|Resilience||Cut and Tear resistance||Abrasion resistance|
|Corrosion resistance||More tailor able characteristics||Lower cost tooling|
|Non-conductive||Pourable||Low temperature resistance|
|Cheaper Fabrication||Cheaper tooling and prototyping||Cheaper tooling and prototyping|
Some of the Polyurethanes materials that Watts Urethane Products use in the manufacture of components are:
- TDI Ether (PPG and PTMEG)
- TDI Ester
- NDI Ester (Vulkollan)
- MDI Ester
- MDI Poly-capralactone
It is always advisable to discuss your specific application with our sales and service team about the best material for your specific application.