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Special absorbers permit product differentiation

A powder dye absorbs infrared radiation to protect wearers of military and medical eyewear, welders'' face plates and ski goggles, as well as electric utility face shields. It prevents blindness resulting from direct contact with light emitted from lasers. Range finders and sighting weapons using Neodynium/YAG lasers emit light at 1064 nm. Grade 6131 absorbs these laser waves while providing good visible light transmission and thermal stability. The material is based on metal dithiolenes and can be injection molded with high-impact-strength polycarbonate (PC) grades, says Chester C. Swasey, VP sales at Adam, Gates & Co. LLC.

Competitive additives such as cyanines have small molecules, and do not provide the thermal stability necessary to use in molded PC, he says. Another additive, amonium salts, has larger molecules that are more thermally stable than cyanines, but their molding temperature is limited to 232C (480F), whereas metal dithiolenes have a processing temperature up to 271C (520F). However, if injection molded improperly, they can give off an unwanted sulfur odor. They also have a tendency to produce a green tint in applications, says Swasey.

Grade 1114 is for manufacturing injection molded welders'' eyewear. It has high thermal stability in low melt-flow PC providing good impact strength. Like grade 6131, it is soluble in organic solvents such as methanol and acetone, which allows it to absorb infrared energy in such applications as shielding window films and security inks. Adam Gates & Co. LLC, Flemington, NJ, USA; +1 908-237-0300; e-mail: [email protected]

RESINS/COMPOUNDS

Nanoclays reduce weight, provide greater strength

Pairing weight and material savings with the durability to withstand rigorous applications, a polyolefin-based compound uses nanoclay technology for thinwall applications and provides good dimensional strength. Maxxam LST compounds are an extension of the Nanoblend Concentrates. They are reportedly easier to process due to a better dispersion of the clays derived from innovations in exfoliation. PolyOne worked in tandem with Nanocor Inc., a nanoclay manufacturer and partner, to fine tune the process. Because of the greater flow, the material can be run in multicavity tools, and it processes at lower temperatures than glass-filled nylon or ABS counterparts.

Stronger and tougher at a lighter weight, Maxxam compounds also help processors reduce dependence on glass-fiber. They have better aesthetics, chemical resistance, and recyclability. In addition, they promote easy flow and fast cooling, which provide cycle-time reductions. Potential applications include vehicle trim; appliance and power tool housings; packaging liners; containers; closures; pipe fittings; and fascia. (PolyOne Corp., Avon Lake, OH, USA; +1 440-930-1000; www.polyone.com

Ink sticks to plastics better following surface modification

A plastics surface modification treatment, PrimeIT, provides a durable substrate on which to print. Conventional treatments (corona, solvents, plasma, flame) improve wettability but adhesion is not stable and surface modification can be uneven, leading to poor printing quality on plastics, says Hermann Angerer, global coating effects manager at Ciba Specialty Chemicals. A loss of surface tension occurs and stored materials will need to be "bumped up" [Aug. 2003 MP/MPI] before printing is possible. PrimeIT is different because once treated, plastics surfaces can be stored for an unlimited time (provided they are not exposed to UV light) and subsequently printed without further treatment. Surface tension typically remains 48 to 52 dyne/cm.

To obtain the PrimeIT effects, the polymer surface needs to be activated by either corona or plasma treatment to enhance polarity. A reactive photo-initiator is then applied by grafting onto the polymer surface. PrimeIT, a yellowish solution based on isopropyl alcohol and ethyl acetate, is then applied by a standard gravure or flexo roll in thickness of 1 g/sq m. It works best with UV inks, although adhesion of water-based inks is also possible.

PrimeIT is suitable for labels, flexible and rigid packaging, and smart cards. It improves adhesion on oriented polypropylene, PVC, PET, polyethylene, and nylon. Ciba Specialty Chemicals, Basel, Switzerland; +41 61 6364444; www.cibasc.com/primeit

ADDITIVES

Cristobalite helps film

Used in polyethylene or ethylene-vinyl acetate films, quartz-derived cristobalite acts as an anti-blocking agent and provides IR absorbing properties. It is chemically inert and has a neutral white color. Particle size runs from 3 to 60 µm. It can also be surface treated. SCR-Sibelco NV, Antwerp, Belgium; +32 3 2236611 www.sibelco.bc

SEMIFINISHED PRODUCTS

No glare, reflection

Sheet and film treatment specialist Autotype International worked with the Fraunhofer Institute for Solar Energy in Germany to developed Autoflex MARAG (Motheye Anti-Reflection and Anti-Glare) films for use in applications such as flat-panel displays, touch-screen interfaces, and electro-luminescent lamps and lenses for mobile phones and PDAs. They are also suitable for film insert molding. Reflection of visible light is less than 1%, regardless of viewing angle. Combining anti-glare and anti-reflective properties with a scratch-resistant surface, the films can replace multilayer films in these applications. They comprise a base film and flexible, chemically bonded, UV-cured moth-eye structure coating. Autotype International Ltd., Wantage, England; +44-1235-771111; www.autotype.com

REFERENCE MATErIAL

Free datasheets

An Internet-based service, Prospector X5, which provides polymer datasheets of more than 50,000 materials from 400 global suppliers, is available to injection molders free of charge. The service, intended to provide users with full-view datasheets, requires only three mouse-clicks to source.

Besides processing information, the service allows for connection with resin suppliers through a sourcing service to obtain pricing and availability. Processors can search for materials by product name, supplier, material family, and applications.

Data updates are posted every two weeks and the tool includes a molding troubleshooter and plastics glossary. Marketing manager Nathan Potter says that following the introduction of the system at the end of January 2004, the company has signed up 2500 registered users. IDES, Laramie, WY, USA; +1 307-742-9227; www.ides.com

RESINS/COMPOUNDS

Tie polymer binds layers for multilayer films

Orevac 18910, a coextrusion binder with good heat stability and adhesion properties, targets multilayer film and sheet applications for modified atmosphere packaging of foods.

This polyolefin-based material adheres equally to polystyrene, polyethylene, ethylene copolymers, and ethylene vinyl alcohol copolymer barrier layers. It has significantly better adhesion than standard tie layers. This is said to improve mechanical strength of multilayer structures. It has good thermal stability and will not delaminate during product filling at high temperatures. Atofina, Paris, France; +33 1 49007030; www.atofina.com

Downloadable file enables instant access

Operators can store recommended processing parameters for DuPont-made engineering polymers on personal computers with a downloadable MS-Excel file from the plastics.Dupont.com website. It contains key temperature, pressure, time, and other processing conditions for 500 polymer grades, giving process engineers 24/7 access to critical mechanical properties and process guidelines. DuPont Engineering Polymers, Wilmington, DE, USA; +1 248-583-8112; plastics.Dupont.com

ADDITIVES

High-contrast, intricate marking on plastics

A laser receptive pigment, Mark-it, helps provide indelible, fast marking of bar codes, manufacturing, or expiration dates, symbols, and company logos to protect against counterfeiting and provide product differentiation.

"The primary market [is for] non-aesthetic applications, but we are also seeing rapid market growth in aesthetic products," says Stephane Rochard, global marketing manager at Engelhard, the producer.

The pigment has FDA food contact approval with loadings up to .5% in polyolefins, although the company says loadings of only .1% provide high-quality markings.

Symbols can be made in dark letters on transparent and lightly-colored backgrounds, or by applying off-white on dark colors. Engelhard Corp., Iselin, NJ, USA.; +1 732-205-5000; www.engelhard.com

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