GB/T 34675-2017 English PDF (GBT34675-2017)

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GB/T 34675-2017: Determination of volatile organic compound (VOC) content in radiation curable coatings
GB/T 34675-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 87.040
G 50
Determination of volatile organic compound (VOC)
content in radiation curable coatings
ISSUED ON: NOVEMBER 01, 2017
IMPLEMENTED ON: NOVEMBER 01, 2018
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and definitions ... 5 
4 Principle ... 5 
5 Equipment ... 6 
6 Samples ... 7 
7 Test procedure ... 7 
8 Test data processing ... 9 
Determination of volatile organic compound (VOC)
content in radiation curable coatings
1 Scope
This standard specifies the terms and definitions, principles, equipment,
samples, experimental procedures, test data processing for determining the
content of volatile organic compounds (VOC) in radiation curable coatings.
This standard applies to the determination of volatile organic compound (VOC)
content in coatings cured by radiation curing methods such as ultraviolet light
(UV) and electron beam (EB). UV curing and electron beam curing inks and
adhesives can also refer to this standard.
2 Normative references
The following documents are essential to the application of this document. For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) is applicable to this standard.
GB/T 3186 Paints varnishes and raw materials for paints and varnishes -
Sampling
GB/T 5206-2015 Paints and varnishes - Terms and definitions
GB/T 6750 Paints and varnishes - Determination of density - Pycnometer
method
GB/T 6753.4-1998 Paints and varnishes - Determination of flow time by use
of flow cups
GB 18582-2008 Indoor decorating and refurbishing materials - Limit of
harmful substances of interior architectural coatings
GB/T 20777 Paints and varnishes - Examination and preparation of samples
for testing
GB/T 21862.2 Paints and varnishes - Determination of density - Part 2:
Immersed body (plummet) method
5 Equipment
5.1 Metal flat-bottom dish
The diameter is (75 ± 5) mm and the edge height is 5 mm or it can ensure that
the specimen does not overflow. It is also possible to use dishes of different
diameters. At this time, use formula (1) to calculate the mass m of the specimen
used for the test, unit in gram (g):
Where:
mstandard - The value of the specimen mass when the dish is the standard
diameter, in grams (g);
d - The value of the diameter of the bottom of the dish, in millimeters (mm);
75 - The value of the standard diameter of the dish, in millimeters (mm).
Note: The viscous paint can also be made of aluminum foil with a thickness
of about 0.1 mm, which can be cut into a rectangle with a size of (100 ± 10)
mm × (300 ± 10) mm that can be folded in half, so that the viscous liquid can
completely spread.
5.2 Syringe
Disposable syringe with a capacity of 1 mL.
5.3 Oven
Warning - In order to prevent explosion or fire, samples containing volatile
substances shall be handled with care and shall be implemented in
accordance with relevant national regulations.
In order to ensure the safety of the test, a forced convection oven shall be
selected, which can be kept within ± 2 °C of the specified or agreed temperature,
meanwhile is equipped with horizontally placed partitions. A natural convection
oven equipped with perforated metal partitions at 1/3 of the height of the
working chamber can also be used.
5.4 Dryer
Packed with a suitable desiccant, such as dry silica gel impregnated with cobalt
chloride.
mstandard x
a bottle with stopper or into a weighable pipette or a 1 mL syringe without needle (see
5.2). Use the reduction method to weigh (0.5 ± 0.1) g of the specimen to be tested
(accurate to 0.1 mg) into the dish (see 5.1), (at this time, m1 is the sum of m0 and the
mass of the specimen). Spread flatly on the bottom of the dish.
Note 2: If the specimen to be tested is not completely flat on the bottom of the dish
(see 5.1), the incomplete curing due to the partial paint film may make the test result
of volatile content too large.
7.1.5 Immediately after the weighing, immediately transfer the metal flat-
bottomed dish (see 5.1) containing the specimen into oven (see 5.3); heat it at
(50 ± 2) °C for 30 min.
Note 1: This step is to simulate the step of removing inert solvents during industrial
production. If the specimen contains a large amount of inert solvent, direct radiation
curing will result in a big deviation between the test result and the actual result.
Note 2: If the inert volatile content in the known specimen is less than 3%, the step
7.1.5 can also be omitted, and radiation curing can be carried out directly.
Note 3: If the known specimen contains 50 °C volatile reactive diluent (such as styrene,
isobornyl acrylate, etc.), regardless of the volatile content, do not proceed to step 7.1.5.
7.1.6 After the heating time is over, take out the dish. According to the curing
requirements specified for the specimen to be tested, put the specimen into the
curing equipment (see 5.6) for radiation curing.
7.1.7 After radiation curing, transfer the dish into an oven (see 5.3) at (110 ±
2) °C and heat it for 60 minutes. After the heating time is over, place the dish in
a desiccator (see 5.4) to cool and weigh the mass m2 of the specimen residue
and the dish, accurate to 0.1 mg.
Note: For coatings that react with water in the air during curing (such as cationic curing
epoxy UV-curable coatings, etc.), if the specimen is weighed after baking at (110 ±
2) °C for 60 minutes, the mass may increase. If this happens, re-sampling is performed
after the steps of 7.1.1 to 7.1.6; the specimen is then placed in a desiccator at room
temperature for 48 h; then the step 7.1.7 is performed.
7.1.8 The non-volatile content w (NV) (mass fraction) is calculated according to
formula (2):
Where:
m2 - The value of the mass of the specimen residue and the dish, in grams