Rising to the Challenge

Eco-friendly flame retardants

Responding to environmental concerns, Great Lakes Chemical Corp. is phasing out production of two widely-used flame retardant chemicals, penta-and octa-polybrominated diphenyl ether, by the end of 2004. Great Lakes is replacing penta-PBDE with a new product, Firemaster 550. On the basis of preliminary studies, the U.S. Environmental Protection Agency (EPA) has determined Firemaster 550 is not persistent in the environment, bioaccumulative in organisms or eco-toxic.

Firemaster 550 allows customers to make foam that meets both UL-94 standards, as well as the California Technical Bulletin 117 standards, making it suitable for fire protection in foam products commonly found in furniture. Additionally, it can also be used as a fire retardant in insulation foam, packaging foam and accoustical foam; as well as for flame lamination in products such as automobile headliners.

Great Lakes is offering customers Great Lakes FF-880 as a replacement for octa-PBDE. FF-880 is most frequently used in computer, printer, copier and other business machine housings.

Techmer PM, LLC has introduced a new polyester, non-halogenated flame retardant, Techsperse PBM12635, for fibre and film applications. Designed to be used in let-down ratios as low as 10%, Techsperse meets UL-94 V-0 and can be safely processed at temperatures up to 545F.

Bayer Chemicals’ phosphorus-based Disflamoll products perform a dual role as flame retardants with plasticizing properties and can be used with PVC and phenolic resins. Disflamoll TP is used in flame-resistant thermoplastics for office equipment housings. Disflamoll DPK and other products in the line can be used with a wide variety of polymers.

Clariant Corp.’s Exolit OP 1311 is a non-halogen flame retardant. The metal phosphinate combines the high effectiveness of organophosphorus compounds with properties of mineral-based flame retardants. Exolit is ideal for making flame-resistant, glass-fibre- reinforced polyamides, according to Clariant.

Tough guys: modifiers

Axel Plastics Research Laboratories will be introducing a process aid additive package for increasing the melt flow of HDPE in sheet applications. According to company president Frank Axel, the product is undergoing final testing and should be ready for the market no later than the end of the first quarter of 2004.

“Many of our customers are interested in increasing the speed of their operations,” says Axel.

He reports that health and safety issues related to VOC emissions is another concern for processors. Axel Plastics produces a full line of internal mold release compounds designated by the name MoldWiz INT. Axel says the compounds eliminate the VOCs, and the costs, associated with the use of external mold release agents. MoldWiz INT-38HM, for instance, is formulated for use with glass-reinforced, high-temperature nylon. In addition to providing automatic mold ejection, the product is blended with other additives to improve dispersion of the polymer/glass matrix and eliminate flow lines.

For improved toughness at both room and low temperature, Kraton D1102 and G1652 polymers are both compatible with polypropylene. Table 1 shows low additions of Kraton D1102 to PP homopolymer improves impact strength with only a slight loss in stiffness.

Table 1 Binary blends of Kraton D1102 polymer with PP

Rohm and Hass has introduced EXL-2314, an acrylic impact modifier designed to strengthen and toughen nylons, polyesters and blends. The product’s reactive functionality permits the modifier to chemically bond with the resin matrix, enhancing its ability to improve impact performance. EXL-2314 comes as a free-flowing white acrylic polymer powder.

Protecting films and bottles

Kenrich Petrochemical’s non-silane, neoalkoxy and zirconate titanate coupling agents react with all fillers, pigments and fibres that are silane non-reactive such as CaCO3, boron nitride, carbon black, organic pigments and fibres such as graphite, polyester and aramid. The agents couple to most substrates in situ in water, solvent, liquid polymer or thermoplastic polymer melt without need of condensation water, drying or pretreatment. The products eliminate air voids and moisture to create a true continuous filler/polymer phase thus improving adhesion, strength and resistance to degradation.

ClearShield is Milliken Chemical’s newly-developed UV absorbing polymeric additive for PET containers. A homogeneous liquid polymer, ClearShield blocks all UV rays in wavelengths up to 390 nanometres, providing the highest UV protection available in the industry without package discoloration, according to Milliken.

“Our research has shown that any level of exposure to UV rays can impact the color, flavor, aroma and nutritional value of beverages, and the only way to be certain of eliminating this product quality concern is by blocking all UV rays with 390 protection,” says Mike Purcell, Milliken market manager.

Accurel Systems has added Accurel XP900 to its product line-up. Accurel XP900 is a microporous polyester carrier targeted for PET applications such as blow-molded bottles and extruded film. Pellets can be loaded with up to 50% by weight of liquid, thermally sensitive or viscous additives that cannot be processed by conventional extrusion compounding techniques.

Colorants: not just a pretty face

Arctic Infrared reflecting pigment technology, from Shepherd Color Co., imparts functional as well as aesthetic performance features to a design. Because Arctic pigments have infrared reflecting properties, the end product does not absorb as much heat and remains cooler. Heat build-up within a plastic product can cause warping and twisting. A lower heat build-up also means less thermal degradation of polymers. Arctic Infrared pigment technology allows the use darker colors in exterior applications, such as siding, window, decking, as well as automotive, where previously only white or lighter colors were available.

Shepherd Color’s StarLight line uses glass particles uniformly coated with metallic silver to achieve outstanding brilliance and sparkling effect at low pigment levels. StarLight pigments are compatible with most polymers, blends and alloys and can be processed at high temperatures without concern.

Silberline’s Silvet E1 aluminum pellets are available in an unmatched palette of pigment grades ranging from standard milled flakes, custom engineered lenticular automotive grades and spherical pigments for flow line reduction. Silvet E1 pellets are easy to handle and disperse and can be used to enhance the appearance of plastics in a variety of ways.

Ampacet’s Film Business unit has introduced Optimizing Process and Package Performance, a new program aimed at offering customers innovative and customized masterbatches that ensure package integrity and improved operational efficiency. The program is targeted to help manufacturers of multi-layer blown and cast film, extrusion coating and BOPP, among others. Some of the additives packages that can be formulated include masterbatches to improve water absorption, anti-static and anti-fog properties or prevent film discoloration.

High output, color stable PVC

Crompton Corp.’s Mark 2289 heat stabilizer is designed for vinyl siding, window and door frames being used in extreme heat conditions; especially in the southwest area of the U.S. The stabilizer provides enhanced protecti
on against UV light and dry heat, preventing yellowing and cracking.

“For vinyl, hot, dry conditions are much different and more extreme than hot humid conditions,” says Perry Reed, Crompton manager, rigid PVC additives, technical service. “One of the major issues for PVC in the southwest U.S. is weathering of white PVC.”

Reed says PVC profiles installed in this climate frequently show a delta B color shift of six to eight units in less than a year of exposure. Weathering tests done by Crompton show Mark 2289 reduces color shift to as little as one to two units in two years of exposure. Mark 2289 is a non-sulfur based heat stabilizer which also contains a lubricant package.

Atofina Chemicals Inc. introduced a new processing aid at Vinyltec 2003. Plastistrength 770 is an acrylic lubricating processing aid designed to improve on the metal release performance of traditional lubricating process aids. The product allows PVC extruders to process sensitive formulations more successfully, increase throughput, and reduce downtime. Processors may also find that the 770 process aid reduces the required level of anti-tack processing aid.

“Plastistrength 770 process aid represents a step-change in the performance of metal-release process aids,” says Peggy Shipper, business manager for Atofina, plastics additives. Shipper reports that the additive can be dropped into PVC formulations in place of existing lubricating process aids.

Atofina has also brought out two new heat stabilizers. Thermolite 140 is a butylin mercaptide heat stabilizer specifically designed for co-extruded siding, profile and fence substrates in which good color hold and stability are needed. Thermolite 179, also a butylmercaptide heat stabilizer, is designed for high output extrusion of rigid PVC applications requiring good stabilization, exceptional weathering and excellent color hold.

Crompton’s Mark 2910 is a liquid stabilizer/lubricant package designed for potable water pipe applications. According to Crompton’s Reed, 2910 allows processors to eliminate paraffin wax from resin formulations resulting in much less plate-out on dies and calibrator. This in turn reduces maintenance and enhances the product’s surface finish.

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NANOCOMPOSITES ENTER TRUE COMMERCIAL PHASE

After a decade-long period of intense research and development, plastic nanocomposites are finally turning the corner in terms of commercial applications and prospects of profitability for suppliers and processors who have invested in the technology. Nanocomposites offer the promise of higher performance, for example increased modulus, at lower fill levels than traditional additives.

“2003 is the year nanocomposites went into a real commercial phase,” says Peter Maul, president of Nanocor Inc.

One large push in that direction was provided early last year by the formation of a strategic alliance between resin distribution giant PolyOne and Nanocor, the Arlington Heights, IL-based supplier of nanoclays. Maul describes the alliance as one of close cooperation between the two companies on all technical and sales matters relating to the commercialization of nanocomposite-based polyolefins.

Nanocor sells its montmorillonite nanoclay, called Nanomer, to PolyOne. Using the nanoclay as its base material, PolyOne launched its first commercial line of nanocomposite additives, Nanoblend concentrates, in June 2003. Nanoblend concentrates contain up to 40% nanoclay and are designed to replace traditional mineral or glass reinforcements and flame retardant additives in a variety of olefin-based materials.

Nanocor also has exclusive agreements to sell Nanomer clay to compounders Gitto Global Corp. (Lunenburg, MA.) and Noble Polymers, LLC (Grand Rapids, MI). Gitto Global is selling fully commercial grades of nanocomposite-based, flame retardant plastic compounds. Noble Polymers has just announced the commercial launch of a proprietary polypropylene nanocomposite designed to be a replacement for glass-filled PP in applications such as automotive seating, furniture and appliance components. One additional strategic alliance, this one between Nanocor and Mitsubishi Gas Chemical Company, has resulted in the commercialization of a high barrier nanocomposite nylon for film and bottle applications, Imperm. The resin is currently manufactured in Japan, but Mitsubishi Gas is building a facility to manufacture Imperm in Richmond, VA. The plant is scheduled to come on line in early 2005.

Another supplier of nanoclay, Georgia Industrial Materials, uses a proprietary grinding technology to reduce the size of mica flakes from 100 to 200 microns in length to flakes less than 1.5 microns in length and 0.1 micron thick. President David Avant says the particles produced by the process, when examined under a microscope, are smoother than other types of nanoclay particles used in nanocomposite applications.

“Flat particles are better than rounded or cornflake-shaped particles because they allow you to achieve the maximum surface area enhancement effect in a nanocomposite,” says Avant.

Nanocor’s Maul says his company has developed specific grades of nanoclays for specific applications. “A nanoclay that makes a good barrier application will probably make a bad coatings applications. With a barrier application you want the clay to have a high aspect ratio, and with coatings, not so high.”