scope:

The material defined by this specification is a thermoplastic heat stabilized molding compound based on Polypropylene also known as PP. All PP materials shall contain heat stabilization, but may also include toughening agents, UV stabilization, mineral fill, or glass fill. For purposes of this specification, impact modification and material toughening may be used interchangeably to refer to the material additive that increases impact performance. This specification is created for fastener use only and to address long-term stability of Engineering Drawings for fastener parts. Polypropylene parts shall not contain PCR/PIR resin, but regrind is permitted (See Section 3.3, WRS-M99P42-A1).