BS ISO 15038:1999

This standard BS ISO 15038:1999 Plastics. Organic-perester crosslinking agents for unsaturated-polyester thermosetting materials. Determination of active-oxygen content is classified in these ICS categories:

• 83.040.30 Auxiliary materials and additives for plastics

This International Standard specifies a method of determining the total active-oxygen content of organic peresters.

It applies to those peresters used to initiate crosslinking of unsaturated-polyester thermosets.

The peresters most widely used in the crosslinking of unsaturated-polyester resins are given in Table 1.

Table 1

Main types of organic perester

Perester	Molecular mass
tert-Butyl perbenzoate	194,2
tert-Butyl 2-ethylperhexanoate	216,3
iso-Propyl tert-butylperoxy carbonate	176,2
tert-Amyl 2-ethylperhexanoate	230,3
tert-Amyl perbenzoate	208,3
tert-Butyl 3,5,5-trimethylperhexanoate	230,4

Butyl peresters may contain traces of tert-butyl hydroperoxide (TBHP), the active oxygen in which can be determined separately from that in the perester itself (see annex A). The active-oxygen content of the perester alone can then be obtained by subtraction.