Perstorp has eyes on the environment

Caprolactone derivatives for themoplastic polyurethane elastomers bridge the gap between polyesters and polyethers, Jane Denny investigates 

“If you ever break your hand and need to go to hospital,” says Stephen Lewis, Perstorp’s vp of the caprolactones Capa business unit, “it’s likely you will have a Capa thermoplastic splint fitted to protect the injury from further damage and aid the re-alignment of the tissue.”

This particular use is just one of many application areas and demonstrates some of the properties that Capa Thermoplastics brings to their related polyols, said Stephen Lewis at Perstorp. The homopolymer melts at 60ºC, forms a rigid material at room temperatures.

Capa polyols are aliphatic polyesters made by a ring opening reaction, which Perstorp says give a controlled polydispersivity, very low acid values. There are two series of polyols in the Capa range

The Capa 2 series has a functionality of two and grades are available with molecular weights between 400 and 8000. Capa 3 series materials are tri-functional polyols with molecular weights from 300 to 3000.

Perstorp’s Warrington, UK plant

Perstorp’s entire capalactones capacity is produced at its plant in Warrington, UK – situated almost at the mid-point between Manchester and Liverpool in the north of England.

The plant is 50m high construction of six stories. It is operated by a handful of staff. Overall, around 90 staff work at Warrington site.

Perstorp bought Solvay’s caprolactones portfolio for EUR200m in 2008. At that time it had a turnover of EUR60m. Solvay – which still has its own facility located next door to Perstorp –supplies the raw materials over the fence to Perstorp in Warrington.

"We managed to reduce energy consumption by 30% and our water usage was cut by 55%."

Elin Sohlberg, Perstorp UK

In 2011, Perstorp doubled the site’s capacity.

Elin Sohlberg, md of Perstorp UK, said the firm debottlenecked polyols production shortly after doubling its monomer production capacity. Those moves ended a global shortage of caprolactone products which had lasted for several years.

She said: “The aim was to improve energy consumption. We managed to reduce that by 30% and our water usage was cut by 55%.”

New pilot reactor

The company has continued to invest and installed a pilot reactor at the site in 2014.

Before this, it could offer its customers up to 20kg of new grades of polyols created in its onsite laboratories.

“The next scale up we were able to offer was 5 tonnes, which understandably some of our potential customers considered to be a bit of a high a jump,” said Sohlberg.

She said the pilot reactor was installed to bridge the availability gap between lab-scale and full-plant reactor quantities. The pilot reactor can also be filled with specific customer-focused polymer grades.

“With the new pilot reactor we are able to produce batches up to 800kg. It’s a manual and flexible and almost all grades can be produced in it,” she added.

“Going forward, the pilot reactor is geared up for thermoplastics. We are not only providing manufacturing prototypes in that material but we also have a pilot plant innovation centre,” she added.

Renewable content

According to Sohlberg, Perstorp has well-developed capabilities to put renewable content into the Capa portfolio. The R&D is there and in place, she said. “Sustainability is very close to our hearts.”

One challenge, she noted, is that, “There are currently no incentives for product makers to go in the sustainability direction, it is more expensive and not the something that a business would necessarily choose.” Still, Perstorp has “high hopes” for the future of its bioplastics business, she said.

Lewis agreed, adding: “Bioplastics is growing all the time – that is one of our growth platforms.”

Capa profile

According to Lewis, “Each industry has its own requirements that’s where the specialisation comes in to formulate downstream.

Perstorp’s Capa business is part of the Specialties and Solutions portfolio. Lewis describes Capa as a “multitalented performance enhancer”. He said the company is able to “fine tune the product to make it do something specific”.

In key sectors such as elastomers, polyols made with caprolactones can produce polyurethanes with extreme resistance to wear and tear,” Lewis added.

Capa, Lewis said, provides an “integral strength that [other types of] polyesters and polyethers do not have. What this means is that in seals and gaskets, for example, Capa will keep its form where other materials fail.”

“The market for industrial coatings is an example where the continuing drive to reduce use of organic solvents has seen a wider adoption for our Capa based Polyols,” he said.

“We also sell Capa monomers on open market into resin modification and pigment dispersion applications. We take that monomer and turn it into polyol and thermoplastic production where we make specific solutions, to our formulations and to our customer’s requirements too.

“All of that is supported through our innovation centre and pilot plant,” added Lewis.

Diverse markets

Capa molecules are found in products as diverse as adhesives, automotive, resins, paints and footwear, as well as being a key material for polyurethane and thermoplastic polyurethane-based manufacturers. End uses include skateboard wheels, shoes soles and industrial rollers.

In addition to resin modification, caprolactones can be used for resin, waterborne PUD coatings, cast elastomers, hot-melt adhesives, in-shoe support material and orthopaedic brace supports are among the uses for caprolactones, said the firm.

User-friendly website

Finally, Lewis noted that Perstorp is making digital as well as brick-and-mortar investments. The company updated its website in 2015, a move that he says now allows users to drill down into its diverse product portfolios and find relevant information more quickly.

The site provides “step-by-step guidance into the right product, which is important when you are selling so many grades. Lewis said, “Generally company websites are all chemistry focused, but our system fast-tracks the selection process and avoids potential customers going through hundreds of data sheets.”