Compounders are looking at thermoplastic olefins made with metallocene resins as likely base polymers and additives that will help them to produce new tricks in doggedly old products. While they still are unsure of specific applications, executives for several leading compounding companies said metallocene catalyst technology is offering their companies advantages and opportunities to make new products.
Compounders are looking at metallocene resins from several perspectives:
As distinct base polymers for new products.
As additives for impact modification to replace styrene butadiene rubbers and styrene butadiene styrene block terpolymers.
And, as copolymers to form new alloys.
Compounders are seeing the same benefits that Scott C. Smith, chief operating officer of Sentinel Products Corp., a maker of cross-linked foam and rubber products based in Hyannis, Mass., noted.
``Metallocene polyolefins exhibit a high state of physical properties at lower densities ... [and] provide the look and feel of cellular rubber,'' he said.
In a recent interview, Smith further noted that metallocene polyolefins can be thermoformed, heat laminated and embossed, and can be manufactured in a variety of colors. Also, he said, they do not require additional plasticizers to achieve flexibility, and they do not contain corrosive, toxic or costly chemicals or fillers.
In fact, the fillers, additives and colorants used in metallocene-based polyolefins are the same as those used in standard polyolefins and, if anything, a smaller quantity is needed because metallocenes are engineered more accurately within reactors.
``These are exciting new materials for a compounder to work with,'' Phil Morin, industry manager for general-purpose compounds for Teknor Apex Co. of Pawtucket, R.I., said in a recent interview.
Teknor Apex, like Cleveland-based M.A. Hanna Co. and other compounders, is working on developing custom products using metallocene resins as a base, Morin said.
``They are not drastically different from other polyolefins. They have some different physical parameters, but they handle just like other polyolefins,'' Morin said.
His company is looking at metallocene resins both as impact modifiers and as blended products, alloyed with other resins.
Teknor Apex expects to introduce a family of thermoplastic elastomers and thermoplastic olefins based on metallocene resins by the end of the year, Morin said.
Lloyd Heller, president of H. Heller & Co. of White Plains, N.Y., said he considers metallocene resins today as being at the same stage of linear low density polyethylene resins were in the late 1970s.
Heller said he sees distinct advantages in the resins, but added that he does not believe they will sweep the industry.
``These resins will come along, but it won't be overnight,'' Heller said.
``They are stronger and tougher than other resins, so you don't have to use as much of them. But they process differently and everyone has to be educated how to use them,'' he added.
Meanwhile, Heller said he believes that metallocene resins and compounds will face competition from other resins, especially from PVC resins and compounds that are well-established at prices far below the current prices for metallocene resins.
As impact modifiers, compounders said metallocene resins provide a huge benefit over rubbers: they are in pellet form, and easily are extruded.
While M.A. Hanna also is looking at metallocene resins to replace rubber as impact modifiers, Rick Shafer, strategic marketing manager for Hanna's Engineered Materials Group in Dyersburg, Tenn., said his company is looking at using metallocene resins in blended and alloyed compounds.
However, he noted that Hanna only is experimenting with such alloys now.
``I have no idea of what applications they would be suitable for, but they are almost like polycarbonate and PET alloys, with good chemical resistance and formability. The possibilities for applications are very broad,'' Shafer said.