SH/T 0404-2008 English PDF (SHT0404-2008)

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SH/T 0404-2008: Test method for light stability of paraffin wax
SH/T 0404-2008
PETROCHEMICAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 75.140
E 42
Replacing SH/T 0404-1996
Test method for light stability of paraffin wax
ISSUED ON: APRIL 23, 2008
IMPLEMENTED ON: OCTOBER 01, 2008
Issued by: National Development and Reform Commission of the People's
Republic of China
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Method summary ... 4 
4 Instruments and materials ... 4 
5 Preparation ... 5 
6 Test steps ... 5 
7 Report ... 6 
8 Precision ... 6 
Test method for light stability of paraffin wax
1 Scope
1.1 This Standard specifies the method to determine the light stability of paraffin wax.
It is applicable to paraffin wax, fully refined paraffin wax and semi-refined paraffin
wax for food use.
1.2 This Standard may address certain hazardous materials, equipment and operations.
However, it is not intended to advise on all safety issues related thereto. Therefore,
before using this Standard, it is the user's responsibility to establish appropriate safety
and protection measures, and to develop an applicable management system.
2 Normative references
The provisions in following documents become the provisions of this Standard through
reference in this Standard. For dated references, the subsequent amendments (excluding
corrigendum) or revisions do not apply to this Standard, however, parties who reach an
agreement based on this Standard are encouraged to study if the latest versions of these
documents are applicable. For undated references, the latest edition of the referenced
document applies.
SH/T 0403, Determination method for paraffin wax colour
3 Method summary
Place the specimen dish filled with molten wax into the constant-temperature chamber.
Irradiate for 45min under the condition of ultraviolet illuminance of
12.0mW/cm2±0.3mW/cm2 and temperature of 90.0°C±1.0°C. Then measure the color
of the specimen. Use color number to indicate the light stability of the paraffin wax.
4 Instruments and materials
4.1 Paraffin light stability tester: temperature-illuminance control unit with digital
display, ultraviolet light irradiation heating unit and constant-temperature lighting room.
The ultraviolet illumination control range is 12.0mW/cm2 ± 0.3mW/cm2. The
temperature control range is 90.0°C±1.0°C. The irradiation time is 45min. The
instrument constant-temperature chamber is made of cast aluminum material. The
internal is fillet. Air convection is good and easy for temperature control. The upper
light-receiving surface is made of transparent quartz glass plate. The absorption of
ultraviolet light at the wavelength of 365nm is small. There is a viewing window at the
front of the instrument, which is convenient for observing the irradiation of the
specimen.
4.2 Ultraviolet high pressure mercury lamp: Power is 375W. UV wavelength is 365nm.
The lamp effective arc length is 140mm.
NOTE: When the illuminance of the instrument fails to meet the requirements, the lamp tube shall
be replaced in time.
4.3 UV light meter: It is used to regularly check whether the illuminance of the light
stability tester is within the specified range. It is Type UV-A, with UV-365 probe.
Wavelength range is 320nm-400nm. Peak wavelength is 365nm.
4.4 Quartz glass sheet: The diameter is 55mm±2mm. The thickness is 2.5mm ± 0.5mm.
4.5 Specimen dish: It is made of ordinary glass. The inner diameter is 40mm. The height
is 21mm.
4.6 Beaker: 100mL.
4.7 Oven (or water bath): Can be heated to 85°C and kept constant-temperature.
4.8 AC stabilized power supply: The working voltage is 220V. The power is not less
than 1kW. It is used when the voltage is unstable.
4.9 Instruments and equipment specified in SH/T 0403.
5 Preparation
5.1 Preheat the clean cuvettes, specimen dishes, and quartz glass sheets to 85°C±2°C
in an oven (or water bath).
5.2 Put the specimen in the beaker. Heat and melt in an oven (or water bath) at
85°C±2°C. Use qualitative filter paper to filter.
5.3 Open the lamp chamber of the light stability tester. Wipe off fingerprints and dust
on the surface of the lamp with absorbent cotton dipped in alcohol. Wipe off the dust
on the surface of the quartz glass plate.
5.4 Prepare according to SH/T 0403.
6 Test steps
6.1 Power on the instrument. Press the lighting trigger button. The high-pressure light
is on. Monitor the illumination and temperature.