GB 31604.7-2023 PDF English
US$140.00 · In stock · Download in 9 secondsGB 31604.7-2023: National food safety standard - Food contact materials and products - Decolorization test Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedureStatus: Valid GB 31604.7: Evolution and historical versions
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivery | Name of Chinese Standard | Status |
| GB 31604.7-2023 | English | 140 |
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National food safety standard - Food contact materials and products - Decolorization test
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| GB 31604.7-2016 | English | 70 |
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Food safety national standard -- Food contact materials and products -- Decolorization test
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GB 31604.7-2023: National food safety standard - Food contact materials and products - Decolorization test
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GB31604.7-2023
GB
NATIONAL STANDARD OF THE
PEOPLE'S REPUBLIC OF CHINA
National food safety standard - Food contact materials and
products - Decolorization test
Issued on. SEPTEMBER 6, 2023
Implemented on. MARCH 6, 2024
Issued by. National Health Commission of the People's Republic of China;
State Administration for Market Regulation.
Table of Contents
Foreword... 3
1 Scope... 4
2 Principle... 4
3 Reagents and materials... 4
4 Instruments and equipment... 5
5 Analysis steps... 5
6 Result presentation... 8
Appendix A Examples of typical grey scale and 9-step chromatic transference
scale for assessing staining... 10
Foreword
This standard replaces GB 31604.7-2016 National food safety standard - Food contact
materials and products - Decolorization test.
Compared with GB 31604.7-2016, the main changes in this standard are as follows.
-- The scope is modified;
-- The principle is modified;
-- Reagents and materials are added;
-- Instruments and equipment are added;
-- Analysis steps are modified;
-- The result presentation is modified.
National food safety standard - Food contact materials and
products - Decolorization test
1 Scope
This standard specifies the test methods for discoloration of plastic materials and
products used in food contact.
This standard is applicable to the determination of soak solution coloring and wipe
decolorization of food-contact plastic materials and products with colorants.
2 Principle
The decolorization test is divided into two parts. soak solution coloring and wipe
decolorization. The soak solution coloring uses food simulants or chemical alternative
solvents obtained from the migration test. The grey scale or 9-step chromatic
transference scale for assessing staining is used to evaluate the grade of soak solution
coloring. For wipe decolorization, absorbent cotton moistened and saturated with food
simulants is used to wipe the food contact surface of the sample, and the coloring grade
of the absorbent cotton after wipe is evaluated by using the grey scale or 9-step
chromatic transference scale for assessing staining.
3 Reagents and materials
Unless otherwise stated, the reagents used in this method are of analytical grade and the
water is second-grade water specified in GB/T 6682.
3.1 Reagents
3.1.1 Glacial acetic acid (C2H4O2).
3.1.2 Absolute ethanol (C2H6O).
3.1.3 Isooctane (C8H18).
3.1.4 95% ethanol.
3.1.5 Vegetable oil (olive oil, corn oil). It shall comply with the requirements of GB
5009.156.
3.1.6 Coconut oil (CAS number. 8001-31-8). chemically pure.
3.2 Reagent preparation
Food simulants. They shall be prepared in accordance with the regulations of GB
5009.156.
3.3 Materials
3.3.1 Absorbent cotton. white.
3.3.2 Grey scale for assessing staining. a grey scale for assessing staining that meets
the requirements of GB/T 251 (see Figure A.1 in Appendix A).
3.3.3 9-step chromatic transference scale. a 9-step chromatic transference scale that
meets the standard requirements of the American Association of Textile Chemists and
Colorists (AATCC) (see Figure A.2 in Appendix A).
3.3.4 Colorimetric tube with stopper. 50 mL, colorless, only full and half volume
colorless scale marks.
4 Instruments and equipment
4.1 Electronic balance. The sensitivity is 0.1 g (maximum weighing capacity is >2.0
kg).
4.2 Analytical balance. The sensitivity is 0.1 mg.
4.3 Color assessment booth. It meets the requirements of GB/T 32387, and the light
source is standard illuminator D65.
5 Analysis steps
5.1 Soak solution coloring
5.1.1 Soak solution preparation
The sample shall undergo a migration test in accordance with the corresponding product
standards, GB 31604.1, and GB 5009.156, the food simulants and migration test
conditions shall be selected in accordance with the requirements of the corresponding
product standards and GB 31604.1, and the area/volume ratio used for the migration
test shall be consistent with the area/volume ratio required by the result presentation.
The food simulant or chemical alternative solvent obtained from the migration test is
the soak solution. The migration test shall be carried out in at least 2 parallel tests.
5.1.2 Blank test
Process food simulants or chemical alternative solvents that are not in contact with the
sample to be tested according to 5.1.1, and the soak solution obtained is the blank soak
solution.
5.1.3 Coloring grade assessment
Experimenters shall have no color vision impairment. If laboratory personnel wear
corrective glasses, their lenses must have uniform spectral transmittance throughout the
visible spectrum. If an experimenter performs continuous colorimetry, the person shall
rest for a few minutes at certain intervals to ensure the quality of visual colorimetry.
Take colorimetric tubes with stoppers, add 50 mL of the soak solution that has been
cooled to room temperature and the blank soak solution respectively, and place them
on the colorimetric tube rack in the color assessment booth. Place the colorimetric tube
rack and grey scale or 9-step chromatic transference scale for assessing staining on the
same plane in the color assessment booth, and the experimenter shall observe it in the
horizontal direction. Visually evaluate the grey scale or 9-step chromatic transference
scale grade to which the color difference between the soaking solution and the blank
soaking solution belongs. The corresponding number is the coloring grade of the soak
solution.
5.2 Wipe decolorization
5.2.1 Sample preparation
The samples shall be pretreated in accordance with GB 5009.156, and 2 wipe
decolorization samples shall be prepared for each food simulant. Experimenters are
required to wear disposable nitrile gloves for the wipe test, and ensure that the nitrile
gloves worn do not discolor during the entire test process.
5.2.2 Preparation of food simulants for moistening absorbent cotton
The food simulant used for moistening absorbent cotton is selected according to the
total migration test provisions in the corresponding product standards, GB 31604.1, and
GB 5009.156.
5.2.3 Preparation of absorbent cotton
Take absorbent cotton, cut it into a size of 2 cm×2 cm in an area of uniform thickness,
with a mass of 0.25 g~0.30 g, and completely wet it with the food simulant selected in
5.2.2.
5.2.4 Experimenter's practice and confirmation of wiping force value
Take a plate or sheet of the same material as the sample to be tested, and place it on an
electronic balance (or other equivalent device that can display the wiping force value);
the experimenter presses the moistened absorbent cotton with the pulp of two fingers
(index finger and middle finger) to wipe back and forth 100 times in an area of about 4
cm×2 cm at a speed of about 1 time/s (wipe the absorbent cotton back and forth for one
round in the direction of the sample test, counting as 1 time). When wiping, apply force
evenly along the test surface, and observe the mass display on the electronic balance
throughout the process to ensure that the mass display during the entire wiping process
is stable within the range of 1.0 kg±0.2 kg.
5.2.5 Wipe decolorization test
Within an area of approximately 4 cm×2 cm on the food contact surface of the sample,
press the moistened absorbent cotton with the pulp of two fingers (index finger and
middle finger), and apply a wiping force that meets the requirements of 5.2.4 along the
sample surface to wipe back and forth 100 times at a speed of 1 time/s, to obtain
absorbent cotton after wiping. If an experimenter performs a continuous wipe
decolorization test, the person shall rest for a few minutes at certain intervals to ensure
the stability of the wiping force value.
5.2.6 Blank test
Use the sample of the same material that was confirmed not to be decolorized by wipe
decolorization test as the blank sample, and prepare blank absorbent cotton according
to 5.2.1~5.2.5.
5.2.7 Coloring grade assessment [Translator's note. here should be Wipe
decolorization grade assessment]
Place the wiping absorbent cotton, blank absorbent cotton, and grey scale or 9-step
chromatic transference scale for assessing staining on the same plane of the color
assessment booth. The incident light is at an angle of about 45° to the surface of the
absorbent cotton, and the observation direction is roughly perpendicular to the surface
of the absorbent cotton. Visually evaluate the grey scale or 9-step chromatic
transference scale grade to which the color difference between the absorbent cotton
after wiping and the blank absorbent cotton belongs. The corresponding number is the
wipe decolorization grade.
6 Result presentation
When the assessed grade of the soak solution coloring test result is grade 5, 4-5, or 4.5,
the soak solution coloring test result is represented as negative; when the assessed grade
of the soak solution coloring test result is grade 1~4, the soak solution coloring test
result is represented as positive.
Appendix A
Examples of typical grey scale and 9-step chromatic transference
scale for assessing staining
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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