New generation nylon/ABS alloys target automobile interiors. (Close-Up).

* A family of highly compatibilized alloys of nylon 6 and ABS for injection molding has been launched by Rhodia Engineering Plastics. Technyl Alloy grades draw on both standard and new-generation nylon 6 resins as the continuous matrix phase with ABS as the modifier. The resulting balance of crystalline and amorphous properties reportedly makes the alloys suitable for automotive interior moldings (like consoles), consumer products, appliance housings, sporting goods, furniture, and toys.

"Intimacy between semi-crystalline nylon and amorphous ABS components is achieved by using a high-performance compatibilizer," states Chad Waldschmidt, Rhodia's North American automotive director. The synergistic outcome makes nylon/ABS alloys candidates for replacing PC/ABS, PC/PBT, and straight PC in certain applications.

Industry sources note that earlier efforts to create nylon 6/ABS alloys have met with limited success, but they claim recent advances in compatibilization techniques have brought better results. Reflecting the same trend, BASF Corp. at the NPE show last month introduced into North America the Terblend N nylon 6/ABS family that was launched in Europe last year. BASF claims that its nylon/ABS alloys are gaining ground in auto-interior parts, safety glasses, soap dispensers, and other uses.

Best of two worlds

Advantages of nylon 6/ABS versus competing materials include lower density. Rhodia pegs that advantage at 6% versus PC/ABS, 10% vs. PC, and 14% vs. PC/PBT. Another plus is the high spiral flow of nylon 6/ABS versus all competitive materials. A third advantage is superior acoustic (vibration damping) performance relative to PC/ABS, a favorable feature in auto interior systems.

The ABS component imparts outstanding appearance properties, including superior colorability and better replication of surface texture (such as a low matte finish), which opens potential to eliminate painting. Nylon 6 contributes excellent heat resistance, chemical resistance, and mechanical properties. For example, nylon 6/ABS has a Vicat softening point around 60 C (140 F), higher than that of any of the main competitive resins. The melting point of Rhodia's alloy is 220 C (428 F).

Rhodia's current slate includes unreinforced grades KC 216 and KC 226, the latter being an easy-flow, fast-cycling version of KC 216. Grades KC 241 and KC 256 are impact modified. Compounds with 10%, 15%, and 30% glass, as well as mineral-reinforced versions, have been developed to extend stiffness, strength, and dimensional stability (see table).

Rhodia already reports several successes for its alloys in automotive applications in Europe and Asia. In the center console of a European car, grade KC 246 replaced PC/ABS, offering 6% weight savings, superior energyabsorbing ability, and improved processability. Another success is an air-vent grille in which fast-cycling KC 226 grade replaced ABS by improving chemical and heat resistance and low-matte appearance. Additional automotive targets are instrument panels, air-vent and defroster grilles, and door assemblies. Potential non-automotive applications include motorcycle and scooter fairings.

RHODIA'S NYLON/ABS MOLDING GRADES (50% RH)

                              KC 216       KC 246   KC 216 V15
                        (Unmodified)  (Toughened)  (15% Glass)

Density, g/cc                   1.11         1.08         1.22
Ultimate Elongation, %           300          200            8
Flex Modulus, psi            185,600      159,500      464,000
Notched Izod Impact,
     ft-lb/in.                  10.5         42.8          8.6

NEED TO KNOW MORE?

BASF Corp., Plastic Materials, Mt. Olive, N.J.

[phone], www.basf.com

Rhodia Engineering Plastics, Mississauga, Ont.

[phone], www.rhodia.com