Significance and Use

Polymerization time provides a measure of time during which shellac retains its plasticity and flow properties at the specified temperature before gelling or polymerizing to the tough rubbery insoluble form. This test is important in determining the quality of different lots, useful shelf-life, batch uniformity, and processing characteristics of shellac.

1. Scope

1.1 These test methods cover tests for shellac in the dry button or powder form to be used for electrical insulating purposes. Typically, shellac is used as a bonding agent for mica splittings and reconstituted mica paper products, or as a coating or adhesive for other material.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Note 1There is no similar or equivalent IEC standard.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D29 Test Methods for Sampling and Testing Lac Resins

D1711 Terminology Relating to Electrical Insulation

D5032 Practice for Maintaining Constant Relative Humidity by Means of Aqueous Glycerin Solutions

D6054 Practice for Conditioning Electrical Insulating Materials for Testing

E104 Practice for Maintaining Constant Relative Humidity by Means of Aqueous Solutions

Keywords

bonded mica; electrical insulation; flow; polymerization time; shellac; Bonded mica; Electrical insulating materials; Electrical insulating shellac; Electrical insulating solids; Flow and flow rate--insulations; Polymerization time; Polymers (electrical insulation applications);

ICS Code

ICS Number Code 29.035.60 (Varnished fabrics)

DOI: 10.1520/D0411-08

ASTM International is a member of CrossRef.

ASTM D411