GB/T 35256-2017 PDF English
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Textiles -- Tests for colour fastness -- Artificial weathering -- Exposure to filtered xenon-arc radiation
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GB/T 35256-2017: PDF in English (GBT 35256-2017) GB/T 35256-2017
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.080.01
W 04
Textiles - Tests for colour fastness - Artificial weathering -
Exposure to filtered xenon-arc radiation
(ISO 105-B10:2011, MOD)
ISSUED ON: DECEMBER 29, 2017
IMPLEMENTED ON: JULY 01, 2018
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions... 6
4 Principle ... 7
5 Apparatus and materials ... 7
6 Test specimens ... 13
7 Exposure conditions ... 14
8 Procedure ... 15
9 Assessment ... 17
10 Test report ... 17
Appendix A (Informative) Typical applications and exposure durations ... 19
References ... 20
Textiles - Tests for colour fastness - Artificial weathering -
Exposure to filtered xenon-arc radiation
1 Scope
This Standard specifies a procedure for exposing textiles to artificial weathering in
filtered xenon-arc apparatus (including the action of liquid water and water vapour) in
order to determine the weather resistance of the colour of textiles. The filtered xenon-
arc light source in the test chamber simulates the solar spectral irradiance specified in
Table 4 of CIE 85:1989.
This Standard applies to the testing of textiles for either their weather fastness or aging
resistance; it also applies to white (bleached or optically brightened) textiles.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
GB/T 250, Textiles - Tests for colour fastness - Grey scale for assessing change in
colour (GB/T 250-2008, ISO 105-A02:1993, IDT)
GB/T 6151-2016, Textiles - Tests for colour fastness - General principle of testing
(ISO 105-A01:2010, MOD)
GB/T 6529, Textiles - Standard atmospheres for conditioning and testing (GB/T
6529-2008, ISO 139:2005, MOD)
GB/T 16422.1, Plastics - Methods of exposure to laboratory light sources - Part 1:
General guidance (GB/T 16422.1-2006, ISO 4892-1:1999, IDT)
GB/T 32616, Textiles - Tests for colour fastness - instrumental assessment of change
in color for determination of grey scale rating (GB/T 32616-2016, ISO 105-
A05:1996, MOD)
CIE 15, Colorimetry (Third edition)
CIE 51.2, A method for assessing the quality of daylight simulators for colorimetry
CIE 85:1989, Solar spectral irradiance
be comparable. Both two types of thermometers shall meet the requirements of GB/T
16422.1. Generally, BST and BPT do not give the same readings.
In weathering devices where specimens are positioned in a flat plane in front of a light
source, a black-standard thermometer shall be used.
Note 1: The BST differs from the BPT because the black plate of the BST is fixed on a
thermally insulated mounting. The temperatures measured therefore
correspond approximately to those measured on the exposed surface of the test
specimen with a black or dark-coloured coating on a substrate of low thermal
conductivity. The surface temperatures of light-coloured test panels will
usually be lower.
Note 2: The surface temperature of a test specimen depends on a number of factors,
including the amount of radiation absorbed, the amount of radiation emitted,
thermal-conduction effects with the test specimen and heat transfer between
the test specimen and the air, and between the test specimen and the specimen
holder, and cannot therefore be predicted with accuracy.
Note 3: In a typical exposure environment (no high irradiance), the BST temperature is
usually about 2 °C ~ 5 °C higher than the BPT temperature.
Note 4: The black-standard thermometer is also called insulated black-panel
thermometer. The black-panel thermometer is also called uninsulated black-
panel thermometer.
5.4.2.1 Black-standard thermometer (BST)
The black-standard thermometer for measuring the black-standard temperature in the
plane of the test specimens during the dry period shall consist of a plane stainless-steel
plate with a thickness of about 0.5 mm ~ 1.0 mm. The typical length and width is about
70 mm × 40 mm; the surface of the plate facing the light source shall be coated with a
black layer that has good resistance to ageing. The coated plate shall absorb at least 90%
of all incident flux up to 2 500 nm. A platinum resistance sensor shall be attached in
good thermal contact to the centre of the plate on the side opposite the radiation source.
The side of the stainless-steel panel on the side opposite the radiation source shall be
attached to a 5 mm thick base-plate, which is made of unfilled polyvinylidene difluoride
(PVDF). There is a small recess that is sufficient to hold the platinum resistance sensor
in the PVDF base-plate. The distance between the recess in the PVDF base-plate and
the sensor shall be about 1 mm. The length and the width of the PVDF plate shall be
sufficiently large to ensure that no metal-to-metal thermal contact exists between the
black-coated metal plate of the black-standard thermometer and the mounting holder
into which it is fitted. The metal mounts of the holder of the insulated black panel shall
be at least 4 mm from the edges of the metal plate. As long as the exposure equipment
can reach the set stable temperature and irradiance conditions, and the indicated
temperature of the selected thermometer of other structures is within ±1°C of the
not contaminate the water employed. In case of immersion, the BST or BPT sensor shall
also be completely immersed.
The conductivity of the spray water shall be less than 5 μS/cm; the insoluble content
shall be less than 1 μg/g; no visible stains or deposits shall be left on the surface of the
specimens. The silicon content shall be kept below 0.2 μg/g. A combination of
deionization and reverse osmosis can be used to produce water of the desired quality.
Note: Wetting of the samples by water spray or by immersion does not necessarily lead
to similar results.
5.6 Specimen holders
Specimen holders shall be made of inert materials that will not affect the test results.
The specimen holders are preferably made in the form of an open frame. If required, a
metal plate can be used to close the specimen holder from the rear.
Additional devices may be used to mount different types of specimens. An open inner
metal frame, which can take up thin textile specimens sewn to a ring, can be used inside
the main frame. Otherwise, inert materials, such as metal or specifically neutral plastic
sheets, can be used to mount specimens. White cardboard without an optical brightener
can be used when applying exposure conditions without water spray.
Opaque covers, made from inert materials (such as thin sheets of aluminum or plastic)
may be used to partly cover a portion of the specimens. White cardboard without an
optical brightener can be used when applying exposure conditions without water spray.
Places not used for specimens shall be filled with dummy specimens, such as neutral
plastic plates or stainless-steel plates, in order to obtain uniform exposure conditions.
Details on specimen holders and mounting of the specimens shall be included in the
test report.
5.7 Spectrophotometer
The spectrophotometer for colorimetric measurement of colour difference shall comply
with GB/T 32616.
5.8 Colour-matching lamp
The colour-matching lamp for assessing change in whiteness shall be in accordance
with CIE 15 or CIE 51.2.
5.9 Grey scale for assessing change in colour
The grey scale shall be in accordance with GB/T 250.
5.10 Reference materials
It is recommended to use appropriate reference materials (see 3.1) to check the exposure
apparatus and operating conditions by monitoring the know function of the reference
material in change of colour (or a different suitable property) depending on the radiant
exposure.
For sets of exposure conditions A and C, the use of Blue Wool References 1 ~ 8 or L2
~ L9 is not recommended, because they are not designed for exposure to wetting.
Note 1: In plastic and polymer coating industries, thin aluminum sheets coated with
orange paint can be used to check the exposure apparatus. This reference
material is mainly sensitive to irradiance, and to water spray intensity, if
applicable. Nevertheless, there are no data available yet on the use of this
material for application.
Note 2: The function of the change in colour or a different suitable property depending
on the radiant exposure or test duration, under specified exposure conditions,
can be provided by the manufacturers of reference materials.
5.11 Metal or clear plastic sheet (PMA)
Sheets made of solid inert material (metal or clear plastic), on which to mount the textile
specimens (see 6.1.3).
6 Test specimens
6.1 For artificial weathering with water spray
6.1.1 If multiple specimens are placed on the same specimen holder in the vertical
direction, the dye washed out from the upper specimens may stain the lower specimens.
The stained specimens shall be discarded and exposure shall be repeated.
6.1.2 Open loop method: A piece of textile is cut into approximately 40 mm × 100 mm,
sewn into a ring, and firmly embedded in a 40 mm wide frame made from a metal wire
of approximately 4 mm in diameter. If an open specimen holder is used, the rear of the
specimen should be closed with a metal plate to expose the entire front of the specimen.
6.1.3 Alternatively, place a specimen not less than 30 mm × 45 mm on the backing plate
of the inert material (5.11). Exposing the whole surface without covering is preferred,
but if required, a thin aluminum plate or an opaque plastic plate can be used to cover
part of the specimen. The covers should be in close contact to the specimens, in order
to mark sharp lines between exposed and covered areas. The covers can be applied as
usual from left to right. However, if bigger specimens (e.g., 100 mm × 45 mm) are
available or more than one step exposure is required, using covers of increasing sizes
from step to step, covering from top down is recommended, in order to minimize water
retention inside the specimen holders.
(CIELab) value is compared with the known value of the reference material. If the value
does not lie within the specified tolerances, the exposure apparatus has to be readjusted.
Reasons for deviations can be:
-- differences in irradiance adjustment or measurement by the test apparatus;
-- differences in temperature;
-- differences in the position of the reference specimen within the test apparatus;
-- exposure apparatus not properly calibrated.
8.2 Mounting of the test specimens
Fix the specimen in the appropriate specimen holder; if necessary, cover part of the
specimen surface. Covering arrangements depend on the agreement of the parties
involved, the type of exposure conditions, and the preparation of test specimens as
specified in Chapter 6. Identify the specimens by suitable indelible markings.
In order to obtain consistent results in long-term exposure, the position of each
specimen can be changed periodically. However, this is not recommended for a short
time exposure.
8.3 Exposure
8.3.1 Exposure for a fixed duration or radiant exposure
Expose the specimen or a group of specimens to specified exposure conditions for the
desired duration or radiant exposure. If applicable, change covers according to the
positioning and timing protocol that has been agreed on by the parties involved. After
exposure, remove the specimens from the specimen holders, and store them in the dark
under normal ambient conditions under the standard conditions specified in GB/T 6529
for at least 5 h to allow acclimatization and relaxation.
8.3.2 Exposure to a control material
Expose the specimen or a group of specimens simultaneously, together with the control
specimen, under the specified exposure conditions. Regularly check the specimens in
comparison to the control specimens, until the color difference between the exposed
part of the control specimen and the original control specimen (weathering with wetting)
or the covered part of the control specimen (weathering without wetting) can be clearly
identified. Stepwise exposure, by covering parts of the exposed specimens and the
control specimen, can be applied.
Note: In general, when the colour change reaches level 4 of the grey scale rating, it is
considered that the color difference can be clearly identified.
After exposure, remove the specimens from the specimen holders, and store them in the
dark under normal ambient conditions under the standard conditions specified in GB/T
6529 f or at least 5 h to allow acclimatization and relaxation.
9 Assessment
9.1 Colour change
Assess the relevant colour changes under the illumination specified in Chapter 15 of
GB/T 6151-2016.
For tests with water spray (conditions A and C), the exposed portion of the specimen is
assessed against the original specimen.
For tests without water spray (conditions B and D), the exposed portion of the specimen
is assessed against the covered part of the specimen.
The assessment is done either by using the grey scale for colour change according to
GB/T 250, or by using spectrophotometric measurements, followed by calculation of
corresponding grey scale ratings according to GB/T 32616. Ratings are in the range of
5 (no visible colour change) ~ 1 (very strong colour change).
Results may also be obtained by measuring the color change value ΔE* (CIELab) or
other colorimetric systems, if agreed upon between interested parties.
It is also possible to compare the colour change of the specimen with the control
specimen agreed by the relevant parties according to the exposure method specified in
8.3.2. If the specimen under test has the same or lower colour difference than the control
specimen, the test result will be given as “satisfactory”. If the specimen under test has
a higher colour difference than the control specimen, the test result will be given as
“unsatisfactory”.
9.2 Ageing behavior
Assess the change in the selected property (ageing criterion) in accordance with the
appropriate test standard.
10 Test report
The test report shall include the following contents:
a) a reference to this Standard.
b) specimen description.
c) type of the exposure apparatus.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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