By Bob Lebeaux, President, The Plastics Group of America
November 11, 2009 in Polypropylene
If you have mixed color unfilled polypropylene scrap and would like to reuse it for another application but need to increase its physical properties, specifically its strength and stability, we can help. Applications like this are right up our alley. We can compound your scrap with a mineral filler to give you the properties you seek. The type and percentage of mineral would be determined by what properties you are looking for. The only limitations you may run into would be color and the final Melt Index of the compounded material. The Melt Index may go lower when we add the mineral filler, but this can be adjusted. The color you can get will be determined by the feed stock polypropylene (for instance, it is difficult to get a light color from a dark feed stock).
You can check our web site and see varying physical properties for the types and percentages of mineral reinforcing agents. When you find the specification you need, The Plastics Group can recompound your scrap polypropylene feedstock with the mineral you choose and provide it back to you in pellet form for reuse. This is the beauty of polypropylene - instead of throwing it away, it can be easily and successfully recycled.
By Bob Lebeaux, President, The Plastics Group of America
October 13, 2009 in Polypropylene
Myth: Using glass-filled materials will rapidly wear out molds and molding machines.
Fact: Once the resin is melted, the wear is not much higher than for mineral-filled materials. However, wear will be higher in material handling systems where pellets abrade the lines and hoppers. Thicker transfer lines and gentle radii on all bends will minimize this issue.
By Bob Lebeaux, President, The Plastics Group of America
October 7, 2009 in Polypropylene
Olefins, like polypropylene and polyethylene do not adhere to metals particularly well because of the non-polar nature of their base molecules. To significantly improve their ability to bond to metals, simply add polar copolymers. This can be done either in the reactor or by compounding with polymers with polar side-groups like acid copolymers such as EVA, EMA, and EMAA.
Polypropylene is available in maleated acid copolymer which has several percent maleic anhydride bonded onto the polymer chain.High temperatures and fast injection help to measurably enhance the bond. For other processes, such as coextrusion/lamination, the use of film-grade polar copolymers is well-established; they are often used to integrate a metallic component, such as aluminum foil barrier layers, into a multi-layer film structure.
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