ADDING PROCESS FLEXIBILITY TO RIGID PLASTIC

The world first polymer-specific masterbatch for rigid PVC is aiming to change the European coloured PVC compound market.

An innovative material believed to be the world's first polymer specific colour masterbatch for rigid PVC could be poised to change the PVC compound market in Europe.

Vynacol is based on patented PVC colouring technology that is used to make it as easy to colour PVC as any other plastic material. The masterbatch has the potential to turn the PVC processing market inside out by allowing processors to cash-in on the benefits of lower polymer costs, reduced stock holding and production flexibility.

Universal and polymer specific masterbatches for flexible PVC have been available for many years but they have never work reliably in rigid PVC. There are many reasons for this: PVC is a complex material that is highly sensitive to the introduction of additives. For example, a universal masterbatch may be unsuitable in rigid PVC because the carrier lubricates the compound. Processors of the material have always had to find just the right grade for their particular plant and application. Consequently these are literally thousands of PVC formulations on the market with varying amounts of additives and different levels of compounding; all developed to meet the specific performance and processing requirements, or both. In these circumstances is it expecting too much for a universal to work effectively in every grade?

Conversely, polymer specific masterbatches for flexible PVC contain plasticisers. Although this does not present compatibility problems when used in rigid PVC, you are, in effect, adding plasticisers to a polymer chosen specifically for its unplasticised characteristics. This in turn can lead to application failures due to plasticiser migration and changes in physical properties in the final product.

What makes Vynacol different is that it works well both in rigid and flexible grades without any of these inherent compatibility and homogenization problems. The free-flowing granular product overcomes all the traditional difficulties associated with adding colour to rigid PVC via the masterbatch route."

Additionally, grades can be tailored to suit individual manufacturing processes. This is important because PVC has never been the easiest of materials to work with, a formulation that runs well on one machine may present processing difficulties on another, even identical, manufacturing plant.

SECRET FORMULA

Perhaps not surprisingly the formulation and manufacturing techniques used to produce this new masterbatch are closely guarded secrets, but the company does say they are based on existing polymer technology and involve specially modified manufacturing plant.

Ingredients have been selected for good weatherability and excellent colour aging characteristics. Further enhancements to outdoor performance are possible by adding UV stabilizers and absorbers while suitable approved pigments allow the masterbatch to meet all European food contact, packaging and EN71 (toy) criteria.

Generally dispersed at recommended dosage of 1-2% and can be used in filled as well as unfilled grades. Depending on thickness and opacity required, dosing in excess of 8% is possible with no effects on processing or physical properties. In fact the product can improve and enhance the characteristics of the base PVC; these are cited as ease of processing, improved weld strength, increased ductility, increased strength (especially at low temperatures), and high gloss finish.

SLOW START

Following its UK launch in July 2000 initial market response to Vynacol was tentative, but over the past year sales have risen dramatically and now account for over 600 tonnes per annum for the Welsh manufacturer.

There were several reasons for the guarded reactions at first shown by UK PVC processors. After 30 years of managing without a 100% reliable masterbatch for rigid PVC the market had, understandably, been predisposed towards precoloured compounds. So when we came up with a product that worked in both PVCu and PVCp the first reaction was one of skepticism. However, once a few processors trailed it word got around that Vynacol worked effectively and orders started to roll in.

Given that PVC is one of the most versatile and adaptable plastics used worldwide - the British Plastics Federation estimated consumption in the UK of 728,000 tonnes in 2001 - the market potential for colouring PVC with Vynacol polymer specific masterbatch is huge.

"These are exciting times, as the full potential for Vynacol is begun to be realised in Europe"