As a tiny niche in the plastics world, rotational molders should stop worrying that resin companies ignore them, and focus on buying resin from specialty compounders that target rotomolding, industry officials said at a Society of Plastics Engineers conference.
Hedstrom Plastics is buying a lot of compounded material, said President Jim Braeunig. He gave the keynote speech for an April 12 session on materials during the SPE rotomolding event in Cleveland.
PE prices have climbed this year, thanks to low inventories and outages of ethylene feedstock. Braeunig said prices should come down over the summer months, and he believes more capacity is coming on stream in China and the Middle East. Even so, Braeunig said rotomolders should not get their hopes up that big resin makers will pay much attention to rotomolding.
With rotomolding resins only being 1 percent of global demand, will they ever make the grades that we're interested in? Probably not. They're going to be making injection and blow molding resin, so I'm not sure if the new capacities are going to help us that much, he said.
PE accounts for 95 percent of the rotomolding industry's demand, mostly for large tanks. Rotomolders need to diversify using compounded materials, to turn out new products with innovations such as molded-in graphics, granitelike finishes or those from conductive materials to dissipate electrostatic discharge, Braeunig said.
Urging molders to work with specialty material suppliers, Braeunig said: These are where the opportunities in rotomolding exist and I'm not certain that we've really harnessed out attention and efforts to capturing that.
A touch of creativity helps. Hedstrom Plastics, based in Ashland, Ohio, has won business with a line of protective boat fenders sporting NCAA college logos. While Hedstrom makes its basic line of fenders in China, these customized products are all made in Ashland, he said.
Another speaker, Stephen Copeland, president of compounder Jerico Plastic Industries Inc. of Wadsworth, Ohio, highlighted some challenges for rotomolders doing in-house recycling. Rotational molders began looking to use recycled material in the late 1980s, as PE prices went up, he said.
Copeland said recycling's not as easy as it seems.
Materials must be segregated and standards set for testing and productivity, according to Copeland.
Before the parts can be run through a granulator, workers have to carefully remove metal inserts, labels and steel-wool vent tubes, which can be labor intensive. If anything slips through it can ruin the granulator blades.
Most people have a whole range of parts and each one's going to have its own issues in getting ready to grind, Copeland said.
Many rotomolders choose to outsource the work to toll compounders, he said.
Cheryl Wilson of toll pulverizer Brunk Corp. said it's important to document, measure and analyze data about materials for density, color, softness, pellet counts and other factors.
If it moves, calibrate it. If it breaths, train it. Your data will tell you what you need to know, said Wilson, quality assurance and technical sales manager of Brunk in Goshen, Ind.
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