Page 232 - Engineering Plastics Handbook

Polyphenylene Ether (PPE) Blends and Alloys 199

■ Low thermal conductivity
■ Excellent energy and shock absorption capability
■ High strength-to-weight ratio
■ Excellent dimensional stability
■ Resistance to moisture
■ CFC and HCFC free
■ Recyclability

This versatility offers opportunities in automotive interior applications
(door padding and panels, knee bolsters, head restraint systems, sun visors,
instrument panels, rear parcel shelves), exterior applications (bumpers,
body support), and cavity filling (car trunks, floor systems).
Noryl EF expandable beads, an interpolymer of PPE and expandable
polystyrene EPS, are available in 100, 200, and 300 series. FR grades use
a nonbrominated, nonchlorinated flame retardant. The grades are listed
below along with an indication of their thermal stability, i.e., temperature
at which there is no significant deformation after 1-h exposure (ISO 2796-
1980). These grades and key features include

Noryl EF 150 and EF170: Medium heat resistance, 219°F (104°C)
Noryl EF 150FR and EF170FR: Flame retardant; medium heat
resistance, 219°F (104°C)
Noryl EF 250 and EF270: Higher heat resistance, 230°F (110°C)
Noryl EF 350 and EF370: Highest heat resistance, 244°F (118°C)

Blow-molding grades. These take advantage of the excellent melt strength
of modified PPE required for extrusion of the hollow parison of molten
resin into various lengths without significant sagging during the process.
In the blowing process, the molten parison is stretched outward to con-
form to the shape of the mold. Modified PPE provides opportunities for
improved extrusion productivity. Blow-molding grades are formulated
with and without a nonbrominated, nonchlorinated flame retardant.
Applications include automotive exterior spoilers, office and hospital fur-
niture, and business equipment enclosures. Representative properties of
blow-molding PPE/PS grades appear in Table 9.8. Blow-molding resins
and key features are

Noryl BN30: 180°F (82°C) HDT at 264 psi (1.82 MPa); UL-94 V-1/
V-2/5VA ratings
Noryl BN31: 180°F (82°C) HDT at 264 psi (1.82 MPa); UL-94 V-0/5VA
ratings