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GB 33372-2020 (GB33372-2020)

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GB 33372-2020: PDF in English

GB 33372-2020
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 83.180
G 39
Replacing GB/T 33372-2016
Limit of volatile organic compounds content in
adhesive
ISSUED ON: MARCH 04, 2020
IMPLEMENTED ON: DECEMBER 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and definitions ... 5 
4 Classification ... 5 
5 Limit of VOC content ... 5 
6 Test method ... 8 
7 Inspection rules ... 8 
8 Labels for packages ... 9 
Appendix A (Normative) Determination of VOC content in solvent-based
adhesive ... 10 
Appendix B (Normative) Determination of water content in adhesive ... 12 
Appendix C (Normative) Determination of acetone, methyl acetate and dimethyl
carbonate ... 17 
Appendix D (Normative) Determination of VOC content in water-based
adhesive ... 21 
Appendix E (Normative) Determination of VOC content in bulk adhesive ... 26 
Limit of volatile organic compounds content in
adhesive
1 Scope
This Standard specifies the limit requirements, test methods, inspection rules
and packaging marks of volatile organic compounds (hereinafter referred to as
VOC) content in adhesive under specified conditions.
This Standard applies to the limitation of volatile organic compounds content in
solvent-based, water-based and bulk adhesives.
This Standard does not apply to:
-- adhesives that are used as intermediates or as raw materials for
production without entering the circulation field;
-- adhesives for testing or evaluation in any research and development,
quality assurance or analytical laboratory;
-- urea formaldehyde, phenolic formaldehyde, melamine formaldehyde
adhesives;
-- special functional surface treatment agent that is applied when materials
are bonded.
2 Normative references
The following documents are indispensable for the application of this document.
For dated references, only the dated version applies to this document. For
undated references, the latest edition (including all amendments) applies to this
document.
GB/T 2793, The method for determination of nonvolatile content of adhesives
GB/T 2943, Terms of adhesive
GB/T 6682, Water for analytical laboratory use - Specification and test
methods
GB/T 13354, Test method for density of adhesives in fluid form - Method of
weight cup
GB 19340, Adhesives for footwear and case and bag
6 Test method
6.1 Sampling
Adhesive product sampling shall be carried out in accordance with GB/T 20740.
6.2 Determination of VOC content
6.2.1 The determination of VOC content in solvent-based adhesive shall be
performed according to Appendix A.
6.2.2 The VOC content in water-based adhesive shall be determined in
accordance with the provisions of Appendix D.
6.2.3 The VOC content in bulk adhesive shall be determined in accordance with
the provisions of Appendix E.
6.2.4 The VOC content of ethyl α-cyanoacrylate instantaneous adhesives shall
be determined according to the method that is specified in Appendix B of HG/T
2492-2018.
6.2.5 The VOC content can also be calculated according to the composition of
the adhesive. When the calculation is not possible or the calculation and
measurement results do not match, the measurement result shall prevail.
7 Inspection rules
7.1 Inspection items
7.1.1 All requirements that are listed in this Standard are type inspection items.
7.1.2 Under normal production conditions, type inspection shall be carried out
at least once a year.
7.1.3 Type inspection shall be carried out in any of the following cases:
-- when a new product is initially finalized;
-- when the product is produced off-site;
-- when there are major changes in production formulas, processes, and key
raw material sources;
-- when production is resumed after 3 months of suspension.
7.2 Product sampling
Appendix A 
(Normative) 
Determination of VOC content in solvent-based adhesive
A.1 Overview
Place an appropriate amount of the adhesive in a blast drying oven at a
constant temperature; measure the amount of the volatiles in the adhesive
within a prescribed time. Use the gas chromatography to determine the content
of low photochemical reaction compounds; use Karl Fischer method or gas
chromatography to determine the water content in the adhesive; subtract the
water content and the acetone, methyl acetate and dimethyl carbonate amount
from the amount of the volatiles in the adhesive, to obtain the VOC content in
the adhesive.
A.2 Test steps
A.2.1 General
Perform two parallel determinations for all tests.
A.2.2 Density
Prepare the mixed sample according to the matching requirements that are
expressed by the adhesive product; after stirring well, measure the density of
the sample according to the method that is specified in GB/T 13354, at a test
temperature of (23 ± 2) °C.
A.2.3 Volatile content of the sample
A.2.3.1 One-component sample
Determine the non-volatile content of the sample according to the method that
is specified in GB/T 2793.
A.2.3.2 Multi-component sample
According to the matching requirements that is expressed by the adhesive
product, take about 2 g of the mixed sample; stir it well quickly; then, measure
the non-volatile content of the sample within 5 minutes according to the method
that is specified in GB/T 2793.
A.2.3.3 Volatile content of the sample
Calculate the volatile content of the sample according to Formula (A.1):
B.3.1.4 Dropping bottle: 30 mL.
B.3.1.5 Magnetic stirrer.
B.3.1.6 Beaker: 100 mL.
B.3.1.7 Petri dish.
B.3.2 Reagent
B.3.2.1 Distilled water: in accordance with the requirements of grade-3 water in
GB/T 6682.
B.3.2.2 Karl Fischer reagent: use appropriate reagents (for samples that do not
contain aldehyde and ketone compounds, the main components of the reagents
are iodine, sulfur dioxide, methanol, and organic bases. For samples that
contain aldehyde and ketone compounds, use special reagents for aldehyde
and ketone, whose main components are iodine, imidazole, sulfur dioxide, 2-
methoxyethanol, 2-chloroethanol and trichloromethane.
B.3.3 Test steps
B.3.3.1 Concentration calibration of Karl Fischer titrant
Add fresh Karl Fischer solvent into the titration cup of the titrator until the liquid
surface covers the electrode tip; use Karl Fischer titrant to titrate to the end
point (drift value < 10 μg/min). Use a micro-syringe to inject 10 μL of distilled
water into the titration cup; use the weight reduction method to obtain the mass
of the water (accurate to 0.1 mg); enter the mass into the titrator; use Karl
Fischer titrant to titrate to the end point; record the instrument displayed
calibration results.
Repeat the calibration until the difference between the two adjacent calibration
values is less than 0.01 mg/mL; find the average value of the two calibrations;
enter the calibration results into the titrator.
When the relative humidity of the test environment is less than 70%, it shall be
calibrated once a week; when the relative humidity is greater than 70%, it shall
be calibrated twice a week; if necessary, calibrate at any time.
B.3.3.2 Sample processing
If the viscosity of the to-be-tested sample is large and cannot be dispersed well
in Karl Fischer solvent, perform an appropriate dilution for the sample. In the
beaker, weigh 20 g (accurate to 1 mg) of well-stirred sample; then, add about
20% of distilled water to the beaker; accurately record the sample amount and
water addition. Cover a petri dish on the beaker; stir on a magnetic stirrer for
10 min ~ 15 min. Pour the diluted sample into a dropping bottle for later use.
Appendix C 
(Normative) 
Determination of acetone, methyl acetate and dimethyl carbonate
C.1 Principle
Directly inject the sample into the gas chromatograph after dilution; use
chromatographic column to separate it; then, use a hydrogen flame ionization
detector to detect; use the internal standard method to quantify.
C.2 Materials and reagents
C.2.1 Carrier gas: nitrogen, purity ≥ 99.995%.
C.2.2 Fuel gas: hydrogen, purity ≥ 99.995%.
C.2.3 Combustion-supporting gas: air.
C.2.4 Auxiliary gas (separate purge and makeup gas): nitrogen that has the
same properties as the carrier gas.
C.2.5 Internal standard: a compound that does not exist in the sample; the
compound can be completely separated from other components on the
chromatogram; the purity is at least 99% or known. Such as: n-heptane, n-
pentane and so on.
C.2.6 Calibration compounds: acetone, methyl acetate, dimethyl carbonate,
whose purity is at least 99% or known.
C.2.7 Dilution solvent: the organic solvent that is used to dilute the sample (it
does not contain any substance that interferes with the test); the purity is at
least 99% or known. Such as: ethyl acetate, n-hexane, etc.
C.3 Instruments and apparatuses
C.3.1 Gas chromatograph, which has the following configuration:
-- inlet of the split device; the lining of the vaporization chamber can be
replaced;
-- programmed heating controller;
-- detector, flame ionization detector;
f) injection volume: 1.0 μL.
D.5.2 Chromatographic condition 2:
a) chromatographic column (confirmation column): polyethylene glycol
capillary column, 30 m × 0.25 mm × 0.25 μm;
b) temperature of the sample injector: 240 °C;
c) detector: FID, temperature of 250 °C;
d) column temperature: programmed heating; keep the initial temperature of
60 °C for 1 min; then, increase to 240 °C at 20 °C /min; keep it for 20 min;
e) split ratio: split injection, split ratio can be adjusted;
f) injection volume: 1.0 μL.
D.6 Test steps
D.6.1 General
Perform two parallel determinations for all tests. Multi-component samples are
the same as A.2.3.2.
D.6.2 Density determination
Perform according to the method that is specified in GB/T 13354.
D.6.3 Optimization of chromatographic parameters
According to the gas chromatography conditions, a known calibration
compound shall be used to optimize the instrument each time, so as to make
the instrument's sensitivity, stability and separation effect at the best state.
D.6.4 Qualitative analysis
Qualitatively identify the presence of calibration compounds in D.3.6.
Preferentially select GC-MS or GC- (FT-IR); perform the determination
according to the given gas chromatography test conditions. The column that is
specified by GC-FID and D.4d) can also be used. Respectively record the
chromatogram of calibration compounds on the two chromatographic columns
(the polarity of the two selected columns shall be as large as possible, such as
6% cyanopropylphenyl and 94% polydimethylsiloxane capillary column,
polyethylene glycol capillary) according to the given gas chromatography test
conditions. Under the same chromatography test conditions, after making the
chromatogram of the test sample, compare and characterize it.
Appendix E 
(Normative) 
Determination of VOC content in bulk adhesive
E.1 Overview
This appendix specifies the determination of the VOC content in bulk adhesives
by the oven method.
E.2 Principle
E.2.1 Place an appropriate amount of the adhesive in a blast drying oven at a
constant temperature; measure the amount of the volatiles of the adhesive
within a prescribed time.
E.2.2 For reactive bulk adhesives (such as acrylates, etc.), give the specified
reaction time (provided by the product supplier); then, measure the VOC
content of the adhesive as E.2.1, so as not to count the reactive monomer into
the VOC content.
E.2.3 For thermoplastic (or thermosetting) bulk adhesive, weight the sample;
operate according to the actual sizing (or vulcanization) conditions that are
provided by the product supplier; then, measure the VOC content in the
adhesive as E.2.1.
E.3 Test steps
E.3.1 General
Perform two parallel determinations for all tests.
E.3.2 Volatile content of the sample
E.3.2.1 Volatile content in general bulk adhesive
same as A.2.3.
E.3.2.2 Volatile content in reactive bulk adhesive
E.3.2.2.1 For reactive bulk adhesive product, take about 2 g of the sample; after
curing according to the curing conditions of the product, determine the
nonvolatile content of the sample according to the method that is specified in
GB/T 2793; calculate the volatile content same as A.2.3.3.
......
(Above excerpt was released on 2020-04-04, modified on 2022-02-20, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/GB33372-2020