Econic’s Business Development Director, Richard French, claimed, ‘CO2 generated in petrochemical plants can be obtained with around 98% purity.’ This implies that if this technology were bolted on to existing processes, there would be little cleaning necessary before the CO2 could be used.
Econic has two catalyst systems, both homogeneous, and Econic anticipates that they will be able to recycle the catalysts, and reuse them.
‘The first technology, Econic’s Alternating Catalyst system, produces alternating polyols and inserts a carbonate group between each of the epoxide molecules, giving a polymer backbone with a very regular array,’ he said. This catalyst allows up to 50% of conventional petrochemical feedstock to be replaced with CO2.
He claimed that reactions using the catalyst systems proceed under very industry-appropriate pressures. ‘You don’t have to ramp up the pressure very high to drive the reaction. It can operate at pressures below 10 bar, giving the customer the opportunity to retrofit the system to their existing assets, and not have to buy a new set of reactors,’ he said.
The highly regular polyols produced give a fairly hard polymer, which can be advantageous in some applications. ‘This can be disadvantageous for other applications for example flex foam,’ he conceded
Understanding this, Econic has developed a Tuneable Catalyst System, where the amount of CO2 can be selected and controlled to fit the final PU property requirements.
French said this system will operate at 6 bar, well within the industrial range for polyol production.
Playing tunes with CO2
Econic believes other existing catalyst systems for incorporation of CO2 into polyols generally require much higher pressures to operate effectively, with some catalyst systems leading to the incorporation of low percentages of CO2 in polyols, while others can only incorporate high levels of carbon dioxide.
‘The Econic catalyst is an organic ligand with a metal centre,’ Sellens said. ‘Our systems are unique. We believe we have clear IP space, and we’ve been building into that space.’
‘If you can go from 0 to 100% CO2, then you can match any potential application. If you can only go low or high, then you are limited. That was always our drive around tuneability. Once you are working in the high CO2 area, polyols on their own are not going to meet all the application needs without blending [with other less viscous polymers]. Being able to dial-up [CO2 content] is really fantastic.’
She added that the viscosity of the polyol drops exponentially as the CO2 content is reduced. ‘If there is a product that can get into the middle-range of CO2 and viscosity, then opening up the range of CO2 containing materials opens up the application spectrum,’ she said.
When I visited the site in early November 2017, Econic was constructing a demonstrator plant at The Heath, a business and technical facility in nearby Runcorn.
‘Although we intend to be a catalyst technology provider, it’s very hard to sell a product if you can’t prove your claims,’ Sellens said. ‘The focus of our portfolio is on the catalysts, not on the work on polyols containing CO2. The demonstration unit is about the validity and credibility of this technology, and the ability to supply small samples of polyol in the 10-20 kg range. For us, the challenge is to find the right people who will move swiftly, and take this technology forward.’
Not as viscous as you think
French added: ‘With Econic Alternating and Tuneable catalyst systems, we believe we can cover the whole polyol market requirement.’
Currently, French said, the company is working on hot-melts. ‘These look good. Metal coatings, rigid foams and elastomers are all areas of interest too.’ The company is also investigating polyols for flexible foams.
Econic presented papers at the recent CPI meeting in New Orleans about both catalyst technologies, as well as work on water-borne polyurethane dispersions.
‘We analysed these dispersions, prepared using 2000 MW diols containing different CO2 contents. We took three industry control standards and used a variety of tests [to characterise the resulting dispersions],’ said French.
He added that some were aged in the dark and in the light for a week at room temperature then subjected to a range of US test methods. The viscosities and physical and chemical properties of the dispersions were well within the acceptable operating windows, with the exception of those containing the alternating polyol.
‘Sometimes, people have the impression that CO2-based polyols are going to be very viscous, and they can be if you go for high CO2 content, but if you can tune the CO2 content, then you can get what you need. Lower CO2 polyols would be applicable for flexible fabric coatings. The polyols were stable in terms of heat stability and yellowness. It is possible to tune the glass transition temperature of polyols by tuning the amount of CO2 present in them,’ he added.
‘We are in different stages of evaluation with a range of people in the industry and we’re quite well into process and product development with a couple of them,’ Sellens concluded. ‘We don’t have any exclusive arrangements. Time and pace can give people the edge.’