IMPORTANT LEGAL NOTICE - The information on this site is subject to a disclaimer and a copyright notice
Banner Research
English
 
  European Commission   > Research > Growth
 
 
Homepage Competitive and Sustainable Growth - Making the European Research Area a Reality
Graphic element
Graphic element
Graphic element
Graphic element Research > Growth > Research projects > Materials & technologies projects > Sticky-back plastic: a new meaning
Graphic element Sticky-back plastic: a new meaning
    04-02-2002
 

A three-year BRITE-EURAM project to improve plastics and paint technologies for automotive, plane and other components linked universities and industry in Austria, France, Germany, Italy and Spain. The partners developed lighter, more economical plastics, plus solvent-free waterborne paints for coating them. The process overcame several technical hurdles and resulted in a cheaper, more productive and more environmentally friendly approach.

Moulded plastics components for cars, planes and other contemporary items such as mobile phones have complex shapes with precise needs for mechanical strength. Until now, extensive use has been made of ABS/PC (acrylonitrile butadiene styrene/ polycarbonate) or for outdoors use, polypropylene (PP), with an outer protective and decorative coating of solvent-borne paint.

However these systems have some major disadvantages:

  • High finishing costs because of the need for pre-treatment of some plastic surfaces - particularly PP - to make the paint stick;
  • High wastage; and
  • Environmental impact of organic solvents.
Stronger and lighter plastics
 
Image
Graphic element

Manufacturers were also keen to obtain lighter plastics with no loss of strength. Advances in moulding and finishing technologies can give a crucial competitive edge in today's highly competitive markets, particularly in the automotive sector.

The consortium set out to develop a lighter plastic by creating a new TPO (thermoplastic olefin) that allowed a reduction in the content of talc - used for structural strength - from 10 to 2%. "This lowers the weight of the plastics components such as bumpers and fascias," says project co-ordinator Franco Ferrarese of Plastal ZCP in Italy. "It also cuts wastage during the moulding phase, because the plastic is easier to work with and fewer parts fail to meet quality standards."

 
Solving one problem creates another
 

While reducing the talc content cuts the weight, it also diminishes the adhesion between the plastic and the paint. There are two ways round the problem of making the paint stick. "The traditional way with PP is to use flame treatment to oxidise the surface, destroying any surface oil or dirt and improving paint adhesion, " explains Mr Ferrarese.

"The other, which is quicker and easier, is to use paints specially formulated for adhesion to PP. However, suitable water-based pigmented primer-surfaces were not available and needed to be developed."

 
Water colours
 
Image
Graphic element

Work at Austrian partner Borealis led to trials with a waterborne paint system. This is applied to the surface of the plastic moulding, and is followed by a final clear coat, which protects the colour layer from the environment and from physical knocks. Reformulating and using waterborne paint for all three layers can avoid the need for flame treatment, making the painting process faster.

Although the paint itself is no less expensive than solvent-based systems, the overall process costs less because it cuts the time and labour involved. Using waterborne paint also avoids the environmental impact of organic solvents, such as ketones or esters, which are much more hazardous and unpleasant to apply, and can carry toxic impurities including dioxins.

 
Multiple approaches
 

The project partners tackled many aspects of the whole system from moulding to quality control. The French Institut Textil et Chimique de Lyon (ITECH) worked on developing the new TPO as well as paint characterisation and adhesion promoter formulation. The University of Barcelona studied the rheological behaviour of the paint - its properties as a semi-solid material under stress - and developed new tests. The University of Padua developed a quality control system for the combination of new-formulation polypropylene and waterborne paint, towards ISO 9001 and ISO 14000 standards targets. The other partners developed a new machinery system for application of the waterborne paints.

According to Mr Ferrarese, the outcome is a very high-quality plastics component to meet the requirements of increasingly demanding manufacturers and consumers.

 
Stronger and lighter plastics
Solving one problem creates another
Water colours
Multiple approaches
   

Key data

Improving the efficiency and cost effectiveness of industrial processes is an important element of the New materials and production technologies key action. This BRITE-EURAM project developed refinements in plastics used for car and plane parts together with suitable new paint technologies.

Projects

Development of innovative systems for waterborne coated plastic surfaces to minimise the environmental impact and to increase product quality (BRPR980674)

     

Homepage Graphic element Top of the page