Chemicals & additives.

Chemicals & Additives

In the field of additives, NPE '91 was alive with color as several suppliers introduced new pigments and concentrates. Seen among these and other products introduced at the show, including stabilizers, flame retardants and processing aids, was a move away from general-purpose, multipolymer additives toward those tailored specifically to one resin family.

PROBLEM-FREE COLORING

Milliken Chemical Co., Spartanburg, S.C., unveiled a non-pigment colorant system that reportedly can overcome some of the problems experienced when pigmented colorants are used with opaque polyolefins. Especially suited for injection molded PE and PP parts, the pelletized Advantage colorants eliminate warpage caused by nucleation, Milliken says, giving the molder greater control over dimensions and performance specifications.

Another colorant designed for use in applications where maintenance of the host polymer's physical properties is critical was shown by Plasticolors Inc., Ashtabula, Ohio. Tests show new Plastisperse provides strong colors without influencing physical properties, making it ideal for thermoplastic elastomers. Plastisperse, a granular, dustless colorant, reportedly provides equal pigmentation at lower usage levels than pelletized concentrates (e.g., applications requiring high levels of [TiO.sub.2] can be colored with about 8% Plastisperse compared to almost 13% of traditional pelletized concentrates).

New fluorescent colorants were introduced by the Day-Glo Color Corp., Cleveland. Five new VC pigments--aurora pink, rocket red, Saturn yellow, signal green and horizon blue--are aimed at use in both rigid and plasticized PVC. They are designed for maximum transparency and can be made opaque by adding one part [TiO.sub.2] for every three parts of pigment. Reportedly, these pigments do not cause buildup on calendering or two-roll mill equipment and have a low degree of plateout. Day-Glo also unveiled 10 new ZQ pigments for coloring injection molded plastics. These pigments--a pink, two reds, two oranges, a pair of yellows, a green, a blue and a magenta--have very good heat stability, the company says, with a maximum recommended processing temperature of 575 F.

Akzo Engineering Plastics, Inc., Neshanic Station, N.J., introduced 12 new PBT-based colors formulated specifically for the fiber optics industry. At a 50:1 usage ratio, the new color line reportedly meets the Electronics Industry Association RS359 Munsell Color Standard. Akzo also used NPE '91 to introduce a line of 10 halogen-free color concentrates for non-halogenated flame-retardant thermoplastics. The colorants are available in black, brown, blue, green, gray, orange, purple, red, yellow and white. Recommended letdowns are 2% except for black, which is 1%. Specific gravities of the concentrates range from 1.31 for red to 1.85 for orange.

With the controversy surrounding reported health risks of heavy-metal colorants (see PT, July '91, p. 56), many suppliers didn't wait for NPE to announce alternatives. But a few siezed the opportunity to add to their metal-free lines.

BASF Corp., Parsippany, N.J., unveiled new cadmium- and lead-free pigments at NPE. Paliogen red pigment is designed for coloring nylon fibers. It reportedly has good thermal stability, excellent color strength and lightfastness, and strong resistance to weathering. BASF says it is targeting the colorant for use in automotive carpeting. The company also announced the culmination of a two-year research effort that has resulted in organic and inorganic cadmium-free colors for all of its acetal, PBT thermoplastic polyesters, nylons, styrenics and high-temperature resins.

The Color Div. of Ferro Corp., Cleveland, added a yellow pigment to its line of nickel and chrome titanates for rigid PVC siding, profiles and engineering plastics. Designated V-9415, the new pigment reportedly provides a strong, bright color with good weather-ability, chemical resistance, process-ability and lot-to-lot consistency. Ferro says that when combined with selected organic pigments, V-9415 can be used to replace many lead and cadmium-based colorants.

The Harshaw Color Div. of Engelhard Corp., Beachwood, Ohio, added a dozen new colors to its Meteor Plus line. The pigments, many of which replace earlier products, are all based on mixed metals and range in color from bright gold to jet black.

FLAME RETARDANTS

A slew of new brominated flame retardants were shown by Ameribrom Inc., N.Y.C. (part of the Dead Sea Bromine Group, Beer Sheva, Israel). Three highly reactive flame retardants that can easily be introduced during compounding were added to the company's Actimer FR line. The thermal stability of these products allows reactive extrusion processing at temperatures above 482 F. Reportedly, the flame retardants' properties are maintained during the extended residence times required by this method. Ameribrom says the flame retardants can be copolymerized or crosslinked, and once they become chemically bonded to the polymer backbone they will not bloom or plate out from the final product.

The new additions to this line are Actimer FR-1025M for processing PBT, PET, nylons and other engineering resins by both reactive and additive routes; Actimer FR-803 for thermal grafting, crosslinking and copolymerization of styrenic and thermoset systems; and Actimer FR-1033, a reactive flame retardant that can also be processed via the additive route. Reportedly, 1033 improves heat-distortion temperature while introducing flame retardancy to the compounded resin. It can reportedly be used as a crosslinking agent in polyolefins for wire and cable applications and can be copolymerized in various styrenic systems, including HIPS, ABS and SMA.

Another brominated flame retardant was introduced by Ferro Corp., Cleveland. New Pyro-Chek LM is designed especially for use with high-impact polystyrene. It reportedly does not produce detectable levels of polybrominated dibenzodioxins or dibenzofurans by itself or when compounded into HIPS resin. It is polymeric and meltblendable, containing 66% bromine. Glass-transition temperature is between 266 and 284 F. Ferro says the benefits of Pyro-Chek LM include higher heat-deflection temperature, improved molded part appearance, and increased melt flow.

JUST FOR VINYL

Many suppliers at NPE stressed stabilizers and other new products aimed at the vinyl market. A new acrylic-based processing aid designed for use with blow molded vinyl bottles or calendered vinyl sheet and film was introduced by Rohm and Haas Co., Philadelphia. Tests show new Paraloid K-130 provides strong optical properties with low haze. For instance, with a 0.025-in. bottle wall thickness, haze was 2.1% [at] 1.4 phr. Rohm and Haas says the additive is very efficient; rheology evaluations of the processing aid reveal fast times to fusion that can improve the speed of calendering without sacrificing clarity. K-130 has a process heat stability up to 575 F.

Rohm and Haas also showed Paraloid HT-510, an HDT modifier it has been promising to unveil since late 1989. The modifier reportedly enables PVC bottles and containers to withstand hot-fill temperatures as high as 195 F. Rohm and Haas says when 20 phr loadings of HT-510, an imide copolymer, were used in hot-filled containers, there was no evidence of migration. The modifier, which the company says complies with FDA regulations for food packaging, is totally miscible in vinyl and does not affect the glass-like clarity of PVC bottles.

The Bedford Chemical Div. of Ferro Corp., Bedford, Ohio, unveiled several new non-cadmium heat stabilizers for automotive and general applications. Among the new high-performance products are Therm-Chek 196, a zinc-based combination powder booster/amine scavenger that reportedly increases process heat stability and delays amine staining. It can be used with vinyl, ABS and nitrile sheet used in auto interiors. Cost is $4.38/lb. Therm-Chek 1180 is a liquid stabilizer containing 90% of Ferro's PS 380 stabilizer along with a uv additive. Reportedly, Therm-Chek 1180 provides good early color hold and prevents color loss due to UV exposure. Therm-Chek 1124 is a liquid heat stabilizer for formulations containing fluorescent pigments such as those found in slush-molded vinyl auto instrument panels and arm rests.

Also new and intended for automotive interior applications are Therm-Chek 1129, a concentrated barium liquid for long-term process heat stability, costing $1.68/lb; Therm-Chek 923, an organic powder that provides long-term heat stability at moderate temperatures for $2.59/lb; and Therm-Chek 195, an amine scavenger, costing $5.98/lb.

Ferro also introduced non-cadmium liquid stabilizers for general applications. The new offerings include Therm-Chek 134, a liquid stabilizer for clear flexible and semi-rigid sheet, which costs $1.50/lb; Therm-Chek 126, a general-purpose, low volatility stabilizer that delivers good optical clarity and balanced heat stability at 2.5-3 phr, costing $1.51; Therm-Chek 139, a liquid with strong color hold and good process heat stability in filled systems that costs $1.45/lb; and Therm-Chek 148, a liquid stabilizer with very good heat stability in clear and filled systems at process temperatures at or above 400 F. It also costs $1.45/lb.

Atochem North America, Philadelphia, introduced two new liquid stabilizers, Thermolite 139 and Thermolite 380. Both are organotin mercaptides with high tin contents. The new stabilizers, which also provide lubricating characteristics, are aimed at use in vinyl siding and window profiles.

OTHER ADDITIVES

Henley Chemicals, Montvale, N.J., exhibited a pelletized masterbatch of Boehringer Ingelheim's Hydrocerol LC endothermic blowing agent. Previously only available in liquid form, the new agent can reportedly be used to foam polycarbonate and other high-temperature resins. Henley says it improves cycle times by as much as 30% and can lead to surface quality on molded parts almost as smooth as the surface achieved by gas counter-pressure molding. Lower required doses and processing temperatures from 518 F to 590 F are other advantages, the company says.

A second generation of Cyasorb hindered-amine light stabilizers that reportedly provide strong compatibility, low color contribution, and very effective light stabilization in a variety of polymers was introduced by American Cyanamid Co., Wayne, N.J. The three products in the new line--Cyasorb UV3581, Cyasorb UV3604 and Cyasorb UV3668--vary in their basicity, making them chemically compatible with a larger variety of plastics.

The new stabilizers are all 100% active liquid HALS and offer thermal antioxidant protection to parts under high-temperature service conditions. Some typical uses are in ABS, polypropylene, and weatherable alloys, Cyanamid says.

PHOTO : Several additive suppliers introduced new concentrates and pigments to fill the developing need for heavy-metal-free colorants. (Photo: Reed Plastics)