Canadian Plastics

Coloring Process Solves Problems of Laser Welding Black TPE

A unique method of coloring thermoplastic elastomers (TPE) has opened up new assembly possibilities for a Canadian automotive parts supplier. The automotive molder was having problems with laser weldi...

September 1, 2003   Canadian Plastics



A unique method of coloring thermoplastic elastomers (TPE) has opened up new assembly possibilities for a Canadian automotive parts supplier. The automotive molder was having problems with laser welding a black component molded of Advanced Elastomer Systems’ Santoprene to a black polypropylene substrate. Apparently, the carbon black inhibited the laser welding, explains Craig Grant of E-Z Color Corp. E-Z Color and an advanced materials firm called Five Star Technologies solved the problem using a process called particle management technology. This process produced smaller carbon particles which were then spin bonded onto the Santoprene resin, resulting in a black colored part that could be laser welded.

“This coloring process gives molders another assembly option for bonding TPE to a substrate, rather than overmolding or co-injection,” explains Dan Collins of Advanced Elastomer Systems (AES). As well, laser welding allows the molder to use a general purpose TPE rather than a specialty grade for overmolding.

The spin bond process “kind of wraps the color around the virgin resin pellets,” explains Grant. It is suitable for a variety of pigments, not just carbon black. As well, there’s no heat history added, and physical properties such as durometer and adhesion are not affected.

It’s also a very cost-effective process compared with buying pre-colored resin, especially for low volumes.

The coloring technique should work on most resins, says Grant, but “the benefits are particularly strong for elastomers because the demand for colored elastomers is typically for low volumes.”

Recognizing the potential for particle management technology and spin bonding, E-Z Color and Five Star Technologies have formed a new partnership called Chemdyne. Chemdyne will pursue micro- and nano- dispersion of particles for applications that require electrical conductivity and the ability to be laser welded.

Chemdyne’s particle management technology (PMT) reduces particles to smaller sizes while maintaining the aspect ratio, so as not to damage the material’s properties. Materials produced using PMT contain loosely held agglomerates, and thus are more easily dispersed during compounding. Because of this, a smaller quantity of conductive material can be used to achieve the same results.

Chemdyne LLC 419-332-8000


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