This standard specifies the determination method for concentrated natural rubber latex residue. This standard applies to concentrated natural rubber latex produced from Hevea brasiliensis latex. GB/T 8293-2001 Determination of concentrated natural rubber latex residue content GB/T8293-2001 Standard download decompression password: www.bzxz.net

GB/T8293--2001
This standard is equivalent to ISO2005:1992 "Determination of Residue Content of Concentrated Natural Rubber Latex". This standard is consistent with the previous version in terms of technical content, with only slight editorial changes. This standard replaces GB/T8293--1987 from the date of implementation. This standard is proposed by the Ministry of Agriculture of the People's Republic of China. This standard is under the jurisdiction of the Natural Rubber Sub-Technical Committee of the National Rubber and Rubber Standardization Technical Committee. The drafting units of this standard are: South China Tropical Agricultural Products Processing Design Institute, and Food Quality Supervision, Inspection and Testing Center of the Ministry of Agriculture (Zhanjiang). The main drafters of this standard are: Yu Heping and Huang Maofang. This standard is the second edition, and the first edition was first issued in July 1987. This standard is entrusted to the Natural Rubber Sub-Technical Committee of the National Rubber and Rubber Standardization Technical Committee for interpretation. 77
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GB/T8293—2001
ISO Foreword
ISO (International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of formulating international standards is usually carried out by ISO technical committees. Any member body interested in the project of an established technical committee has the right to participate in the technical committee. All governmental and non-governmental international organizations that have relations with ISO may also participate in this work. In all aspects of electrotechnical standardization, ISO and the International Electrotechnical Commission (IEC) work closely together. Draft international standards adopted by the technical committees are sent to member bodies for voting. To be published as an international standard, at least 75% of the voting member bodies must vote in favor.
International Standard ISO2005 was prepared by ISO/TC45 Rubber and Rubber Products Technical Committee SC3 Rubber Industry Raw Materials (including Latex) Subcommittee.
This third edition of the standard slightly revises the second edition (ISO2005:1985), abolishes and replaces the second edition. 78
1 Scope
National Standard of the People's Republic of China
Determination of sludge content
Concentrated natural rubber latex
Natural rubber latex concentrateDetermination of sludge content This standard specifies the determination method of sludge in concentrated natural rubber latex. This standard applies to concentrated natural rubber latex produced from Hevea brasiliensis latex. 2 Referenced standards
GB/T 8293—-2001
idt ISO 2005:1992wwW.bzxz.Net
Replaces GB/T8293—1987
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T8290—1987 Sampling of natural concentrated latex (neqISO123:1985) 3 Principle
The test sample is centrifuged, and the residue is repeatedly washed with ammonia-ethanol solution and then dried to constant weight. 4 Reagents
In the analysis, only confirmed analytical reagents can be used, and only distilled water or water of equivalent purity can be used. Ammonia-ethanol solution, composition is as follows:
--Ammonia solution.p0.90g/mL±0.02g/mL ethanol, content not less than 95% (V/V)
5 Instruments
Ordinary laboratory instruments and:
1000ml
a) Centrifuge, generating an average acceleration of about 12000m/s, equipped with two 50mL conical centrifuge tubes. b) Pipette, with appropriate capacity and a lower diameter of about 2mm. 6 Sampling
Sampling is carried out according to the method specified in GB/T8290.
7 Operating procedures
Carry out duplicate parallel determinations, using two centrifuge tubes (5.1) to balance each other. Weigh 40g to 45g of concentrated latex to each centrifuge tube, accurate to 0.1g. Treat each centrifuge tube as follows. Cover the mouth of the centrifuge tube to prevent the surface from forming a crust during centrifugation. Centrifuge for 20 minutes at a speed of about 10000 for 1 hour using a laboratory centrifuge. Use a spoon to remove most of the cream layer, and then use a pipette (5.2) to carefully suck out the upper layer of liquid about 10mm above the top of the slag. Fill the centrifuge tube with ammonia-ethanol solution (4.1), centrifuge for 25 min, and use a pipette to suck out the upper liquid about 10 mm above the top of the residue. Repeat this operation until the upper liquid is clear after centrifugation. Gently pour out the upper clear liquid to the 10 mm mark, add some ammonia-ethanol solution and transfer all the residues into a weighed heat-resistant beaker of about 200 mL. When a small amount of water is left after evaporation, dry it at 70℃±2℃ until the weight loss is less than 1 mg within 30 min. 8. Expression of results
The residue content is calculated according to formula (1) and expressed as mass fraction: mtx 100
Residue content (%) -
Mass of the sample, g,
Where m.
Mass of the residue after drying, g.
The difference between the results of parallel determinations is less than 0.002% (m/m). 9 Test report
The test report shall include the following:
a) This standard number;
b) All details required to identify the sample;
c) The measurement results and their units;
d) Any abnormal phenomena noticed during the measurement; e) Any operation that is not included in this standard but is considered to be applicable.
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