Archive

CASE polyurethanes can be found in a multitude of end-uses: from breathable fabrics to coatings for undersea pipelines; non-slip surfaces to moulded furniture; high tech training shoes to advanced racing car components.

The key to this growth is their versatility - CASE polyurethanes can be soft as skin or hard as bone, light and flexible, or strong and rigid. They can outperform steels and rubbers for abrasion resistance but can also be engineered precisely to produce the finest detail. They can be moulded, sprayed or cast to form any desired size, shape and thickness.

A CASE polyurethane formulation typically comprises a polyol, di-isocyanate, catalyst and other additives, although the polyol is by far the largest single component. Different grades of polyol, varying in molecular weight and levels of cross-linking, can be selected to meet specific end-use requirements.

Modified properties

The physical properties of the formulation can be modified to produce strong adhesives, tough and durable coatings, sealants and elastomers, and even non-setting gels that display high levels of flexibility and resilience.

The CARADOL* range of polyols includes 12 CASE grades. The production process for these grades is different to that used for conventional polyols, as John Johnston, CASE Product Manager, explains: "Our manufacturing process is geared specifically to meet the stability demands of pre-polymer and elastomer manufacturers.

"Most CASE polyurethane systems are applied in liquid form, often in-situ, and formulators need to know that the product won't solidify prematurely," he says.

Sales of CASE grades have doubled in less than five years due to growth in the market. "We have expanded production in recent years but equally important is the emphasis we put on reliability of supply and consistency in product quality," says Johnston. "We concentrate purely on supplying polyols - not systems - and so are not competing with our customers.

"We have also developed a prediction programme, CASE Formulator, believed to be unique in the industry, which is used to evaluate potential formulations and production improvements in a fraction of the time that wet analysis would have taken," he says.

Traditional markets

"Without Formulator, it would not have been possible to implement the batch time reduction programme which allowed the larger tonnage from the plants required to satisfy the ever increasing demand."

Traditional markets including polyurethane binders for making rubber-based playground safety surfaces, wet-pour for running tracks and non-slip car park surfaces continue to be large CASE polyol consumers, and applications are always emerging across a range of other industry sectors.

One of the fastest growing outlets is in the automotive sector where polyurethane sealants are now used in the seams of metal car panels. The sealant prevents the ingress of moisture and air into the seam and has been instrumental in allowing car manufacturers to offer greater warranties against corrosion.

This technique has been universally adopted while polyurethane systems are increasingly being used as a PVC replacement in automotive components, as well as in structural bonding.

Solid elastomers

In solid elastomer form, polyurethane systems are being used as a tyre-fill material for off-road construction plant, access platforms and military vehicles to prevent costly or inconvenient downtime caused by punctures. The polyurethane is pumped into the tyre void to replace the air, eliminating the possibility of deflations from punctures to the tread or sidewall.

Rubber crumb from re-cycled car tyres bound together with polyurethane to form an elastomer is also being used to replace wooden blocks at railway crossings.

In addition to its very long life compared to traditional materials, the attractiveness of polyurethane is due to its hardwearing qualities and dimensional stability in all climates, whilst being easy to install and remove for track maintenance.

High performance polyurethane elastomers help protect and insulate undersea oil pipelines. These syntactic foams typically incorporate a matrix of microspheres to help them withstand the hydrostatic pressures experienced in deep-water environments.

Insulating effect

As well as withstanding pressure and the physical effects of the sea, the insulating effect of the polyurethane helps to maintain the viscosity of the oil over long distances and to promote its free flow. This is of particular importance in the recovery of oil at ever increasing depths of sea water where ambient temperatures are often close to zero Celsius.

The future potential for CASE is well illustrated by the growth of polyurethane adhesives now used across a number of industry sectors, largely resulting from substitution of less environmentally acceptable materials, such as the trend for polyurethane adhesives to replace PVA in timber jointing.

CASE polyols web section

Other articles in this issue

Top ranking ambition
Water works
Capacity to deliver efficiency
Spirit of preservation
Order to cash - made easy
Island of integration
Strengths in adversity
Filter tips
Time-saving software