Full Description

Note: Nothing in this standard supercedes applicable laws and regulations.

Note: In the event of conflict between the English and domestic language, the English language shall take precedence.

Purpose/Material Description.

This specification describes material types of Polycarbonate (PC) that offer exterior weather resistance without the aid of a protective coating. Materials approved to this specification shall meet the requirements of GMW14650 Class 1. This specification is based on GMW3013 per ISO 21305-1/2 recommendations.

Types. There are multiple types within this specification intended for different applications, distinguished by suffix and type number; properties are described in Table 1 and Table 2 and in the following. Suffix generally denotes differences in the polymer chemistry, while Type number generally denotes varying melt flow index. =

• Several types from the aromatic PC copolymer family of resins may be specified:

1. Low Flow Rate, High Molecular Weight Resin, Type 2, suffix CO-T2.

2. Medium Flow Rate, Medium Molecular Weight, Type 3, suffix CO-T3.

3. High Flow Rate, Low Molecular Weight, Type 4, suffix CO-T4.

• Several types from the aromatic PC homopolymer family of resins may be specified:

1. Medium Flow Rate, Medium Molecular Weight Resin, Type 3, suffix HP-T3.

2. High Flow Rate, Low Molecular Weight Resin, Type 4, suffix HP-T4.

3. Higher Flow Rate, Lower Molecular Weight Resin, Type 5, suffix HP-T5.

• One (1) type from the aliphatic isosorbide PC homopolymer family of resins may be specified:

1. Low Flow Rate, High Molecular Weight Resin, suffix AI-T2.

Legacy Types. Type suffixes T1 and LMW-T1 are legacy types and should not be specified. New callouts apply for materials previously approved to these legacy types.

Default Type.

If no type designation is defined, suffix CO-T3 (formerly legacy type LMW-T1) applies as the default standard.

Paintability.

Plastics used for painted applications are required to meet paint performance requirements for new plastic materials per GMW16172. Additionally, painted plastic parts are required to meet painted plastic parts performance requirements per GMW14797.

Symbols.

The material abbreviation according to ISO 11469 is PC.

Applicability.

Typical applications include exterior applications that are exposed to sunlight without an Ultraviolet (UV) protective coating. Consult GM Materials engineer if scratch resistance is important for the intended part application. Not intended for use in optical lens applications for regulated exterior lighting, refer to GMW16729. Not intended for UV-stabilized interior applications, refer to GMW16728.

Remarks.

None.