GB/T 16422.2-2022 Plastics - Methods of exposure to laboratory light sources -Part 2 : Xenon-arc lamps
1 Scope
This document specifies the methods for exposing specimens to the test equipment equipped with xenon arc lamp, heat and humidity. The test equipment simulates the actual end-use environments to daylight or to daylight filtered through window glass, so that the material will have a similar natural aging effect during exposure.
This document applies to the laboratory artificial accelerated climate aging test of plastic specimens exposed to filtered xenon arc lamps under controlled environmental conditions (temperature, humidity and/or wetting). Different types of xenon arc lamps and filters can be combined to meet different test requirements.
Specimen preparation and evaluation of the results are covered in other standards for specific materials.
General guidance of this document is given in ISO 4892-1.
Note: Xenon-arc exposures of paints and varnishes are described in GB/T 1865-2009.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 4582 Plastics - Determination of changes in colour and variations in properties after exposure to glass-filtered solar radiation, natural weathering or laboratory radiation sources
Note: GB/T 15596-2021 Plastics - Determination of changes in colour and variations in properties after exposure to glass-filtered solar radiation, natural weathering or laboratory radiation sources (ISO 4582 : 2017, IDT)
ISO 4892-1 Plastics - Methods of exposure to laboratory light sources - Part 1 : General guidance
Note: GB/T 16422.1-2019 Plastics-Methods of exposure to laboratory light sources - Part 1:General guidance (ISO 4892-1:2016, IDT)
ISO 9370 Plastics-Instrumental determination of radiant exposure in weathering tests - General guidance and basic test method
3 Terms and definitions
For the purpose of this document, the terms and definitions defined in ISO 4892-1 apply.
4 Principle
4.1 A xenon arc, fitted with filters, is used to simulate the spectral irradiance of daylight in the ultraviolet (UV) and visible regions of the spectrum.
4.2 Specimens are exposed to various levels of light, heat, relative humidity and water (see 4.4) under controlled environmental conditions.
4.3 The exposure conditions are varied by selection of
a) the light filter(s);
b) the irradiance level;
c) the temperature during exposure to light;
d) the relative humidity in the chamber during light and dark exposures when exposure conditions requiring control of humidity are used;
e) the way the test specimens are wetted (see 4.4);
f) the water temperature and wetting cycle;
g) the relative lengths of the light and dark periods.
4.4 Wetting is produced by spraying the test specimens with demineralized/deionized water, by immersion in water or by condensation of water vapour onto the surfaces of the specimens.
4.5 The procedure includes measurements of the UV irradiance and UV radiant exposure in the plane of the specimens.
4.6 It is recommended that a similar material of known performance (a control) be exposed simultaneously with the test specimens to provide a standard for comparative purposes.
4.7 Intercomparison of results obtained from specimens exposed in different apparatus should not be made unless an appropriate statistical relationship has been established between the apparatuses for the particular material exposed.
5 Apparatus
5.1 Laboratory light source
5.1.1 General
The light source shall comprise one or more quartz-jacketed xenon-arc lamps which emit radiation from below 270 nm in the ultraviolet through the visible spectrum and into the infrared. In order to simulate daylight, filters shall be used to remove short-wavelength UV radiation (method A, see Table 1). Filters to minimize irradiance at wavelengths shorter than 310 nm shall be used to simulate daylight through window glass (method B, see Table 2). In addition, filters to remove infrared radiation may be used to prevent unrealistic heating of the test specimens, which can cause thermal degradation not experienced during outdoor exposures.
Note: Solar spectral irradiance for a number of different atmospheric conditions is described in CIE 85. The benchmark daylight used in this document is that defined in Table 4 in CIE No.85:1989.
5.1.2 Spectral irradiance of xenon-arc lamps with daylight filters
Filters are used to filter xenon-arc emissions in order to simulate daylight (CIE 85:1989, Table 4). The minimum and maximum levels of the relative spectral irradiance in the UV wavelength range are given in Table 1 (see also Annex A).
Annex C distinguishes two different types of daylight filters: Type I and Type II. These two types meet the relative spectral irradiance requirements of xenon-arc lamps with daylight filters given in Table 1.
Foreword I Introduction III 1 Scope 2 Normative references 3 Terms and definitions 4 Principle 5 Apparatus 5.1 Laboratory light source 5.2 Test chamber 5.3 Radiometer 5.4 Black-standard/black-panel thermometer 5.5 Wetting and humidity-control equipment 5.6 Specimen holders 5.7 Apparatus to assess changes in properties 6 Test specimens 7 Exposure conditions 7.1 Radiation 7.2 Temperature 7.3 Relative humidity of chamber air 7.4 Spray cycle 7.5 Cycles with dark periods 7.6 Sets of exposure conditions 8 Procedure 8.1 General 8.2 Mounting the test specimens 8.3 Exposure 8.4 Measurement of radiant exposure 8.5 Determination of changes in properties after exposure 9 Exposure report Annex A (informative) Filtered xenon-arc radiation - Relative spectral irradiance Annex B (normative) Additional exposure cycles Annex C (informative) Classification of daylight filters Bibliography
