Blog: BASF Polyurethanes expert, Sergio Franyutti, talks hot-cast elastomers
At BASF, we aim to provide a full suite of products and services to make things convenient for our customers. Recently, in the polyurethanes division, we have focused our attention on building up our hot-cast elastomer offerings—an area that was lacking breadth, until last year.
To commemorate our efforts and to bring our customers in on what we’ve been doing, our blog team interviewed Sergio Franyutti, Technical Service Manager/Polyurethane Systems at BASF, to talk about hot-cast elastomers and how they can be used to improve applications in virtually any industry—from mining to medical.
What are hot-cast elastomers?
SF: In the simplest, most basic form, hot-cast elastomers are the product of mixing a liquid prepolymer and a liquid curative together, and then pouring the mix into a heated mold, where the components react to form a solid elastomeric piece. Most often, though, specialty additives are combined into the mixture, which impart any number of characteristics to the finished product.
What makes them so interesting?
SF: In short, their range of properties and use in diverse applications.
Hot-cast elastomers display excellent elasticity, wear resistance, durability, high modulus, high resilience, low-compression set, and dimensional stability over a wide temperature range.
They can be as hard as bowling balls and as soft as gel. And they can be cast into virtually any shape and size. There’s not much you can’t do with this material.
With so many properties, how does BASF choose which polyurethane elastomer to use?
SF: Good question. It is both a science and an art, so there is a lot of testing involved, but here is how we approach each customer’s solution:
- We determine the properties of most importance, and select the polymer/curative system based on that
- Consider the right engineering design principles
- Consult other experts for supplementary information and recommendations, if needed
- Run preliminary tests
- Prototype a few units of the system
- Run a field test, and make comparisons
- Get approval from our customer
- Gear up for production
In what applications are hot-cast elastomers used most often?
SF: Due to high-strength, abrasion- and wear-resistant properties, hot-cast elastomers are found mostly in mining, industrial mechanical, automotive and other demanding applications. Cast polyurethanes are also oil and chemical resistant, so they find their niche in these areas.
You’ll commonly see hot-cast elastomers used for forklift truck tires, coated conveyor belts, gears, mining screens, pipeline pigs and industrial rollers.
What are some of the lesser-known applications they’re suited for?
SF: Because of their reputation for toughness, some people are surprised to learn that cast polyurethanes are used in delicate medical applications, such as implants or filtration membranes of dialysis filters. They’re also used in hydrogels for wound dressings and surgical adhesives.
Polyurethanes make great medical materials in general because they are biocompatible and blood compatible. They’re also hydrophilic and resistant to microbials.
Left with an unanswered question?
Ask Sergio, or one of our other polyurethanes experts, here: http://polyurethanes.basf.us/public/experts/generalinfo/form/true