GB/T 32685-2016 English PDF (GBT32685-2016)

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GB/T 32685-2016: Purified terephthalic acid (PTA) for industrial use
GB/T 32685-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.080.40
G 16
Purified terephthalic acid (PTA) for industrial use
ISSUED ON: JUNE 14, 2016
IMPLEMENTED ON: JANUARY 01, 2017
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Technical requirements ... 5
4 Test methods ... 6
5 Inspection rules ... 7
6 Marking, packaging, transportation and storage ... 8
7 Safety ... 9
Foreword
This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This Standard was put forward by Sinopec Group.
This Standard shall be under the jurisdiction of National Standardization Technical
Committee of Chemical (SAC/TC 63).
Drafting organizations of this Standard: Sinopec Yangzi Petrochemical Company
Limited, Petrochina Liaoning Petrochemical Company.
Chief drafting staffs of this Standard: Ding Daxi, Dai Yudi, Jia Gui, Li Fengsheng.
Purified terephthalic acid (PTA) for industrial use
Warning: If the appropriate precautions are not followed, the products under this
Standard may be dangerous during the process of production, storage,
transportation, and use. This Standard does not intend to make recommendations
for all safety issues related to this product. It is the user’s responsibility to establish
appropriate safety and precautionary measures and determine the applicability of
relevant regulatory limitations before applying this Standard.
1 Scope
This Standard specifies the technical requirements, test methods, inspection rules,
packaging, marking, transportation, storage and safety requirements for purified
terephthalic acid (PTA) for industrial use.
This Standard applies to purified terephthalic acid (PTA) for industrial use, which is
obtained from petroleum p-xylene through oxidation and refining. This product is
mainly used as a raw material for the production of polyester chips, long and short
polyester fibers and chemical products.
Molecular formula: C8H6O4
Structural formula:
Relative molecular mass: 166.13 (according to the international relative atomic mass in
2011)
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies to this document. For
undated references, the latest edition (including any amendment) applies to this
document.
GB/T 3143, Color determination method of liquid chemicals (Hazen unit - Platinum-
cobalt scale)
GB/T 3723, Sampling of chemical products for industrial use - Safety in sampling
GB/T 6678, General principles for sampling chemical products
Carry out in accordance with method A, method B or method C in GB/T 30921.2. When
determined in accordance with method A, the titanium content shall also be determined
in accordance with GB/T 30291.4. Method C in GB/T 30921.2 shall be used as the
arbitration method.
4.6 Moisture
Carry out according to the provisions of GB/T 30921.3; use the Karl Fischer volume
method as the arbitration method.
4.7 DMF color (5 g/100 mL)
Use dimethylformamide (DMF) that meets the requirements for analytical reagents in
GB/T 17521; prepare the test specimen into a 5 g/100 mL dimethylformamide (DMF)
solution; filter it; take the filtrate for determination according to the provisions of GB/T
3143.
4.8 b*value
Carry out according to the provisions of GB/T 30921.7.
4.9 Particle size distribution
Carry out according to the provisions of GB/T 30921.6. If reported by volume fraction,
carry out according to the laser diffraction method; if reported by mass fraction, carry
out according to the air jet sieving method.
5 Inspection rules
5.1 Inspection classification
5.1.1 The product inspection is divided into type inspection and ex-factory inspection.
5.1.2 The type inspection items are all the items specified in Table 1. The type
inspection shall be carried out in any of the following cases:
a) every month during normal production;
b) when the key production process is updated or the main equipment is changed;
c) when there are changes – which affect product quality – in main raw materials;
d) resumed production after suspension;
e) when the exit-factory inspection result is significantly different from the previous
type inspection;
5.1.3 Appearance, 4-carboxybenzaldehyde, p-toluic acid, ignition residue, total heavy
metals, iron, moisture, b* value, and particle size distribution in Table 1 of this Standard
are the ex-factory inspection items.
5.2 Batching
Uniform products of the same quality are a batch. Batches can be grouped according to
production cycle, production shift or product stock bin.
5.3 Sampling
Carry out sampling according to the technical requirements stipulated in GB/T 3723,
GB/T 6678 and GB/T 6679. Take 1 kg ~ 2 kg of test specimen from each batch of
products for inspection and as reserved samples.
5.4 Determination rules
The product shall be inspected by the quality inspection department in accordance with
the methods specified in Chapter 4, and the judgment of the inspection results shall be
carried out according to the full numerical comparison method specified in GB/T 8170.
The manufacturer shall ensure that the quality of all ex-factory products meets the
requirements of this Standard.
5.5 Re-inspection rules
If the inspection results do not meet the requirements of this Standard, double-quantity
samples shall be taken for re-inspection according to the provisions of GB/T 6678 and
GB/T 6679. If the re-inspection results still do not meet the requirements in this
Standard, judge the batch of products to be unqualified.
5.6 Quality certificate
Each batch of ex-factory products shall be accompanied by a quality certificate, which
includes: the name of the manufacturer, product name, production date or batch number
and the number of this Standard, etc.
6 Marking, packaging, transportation and storage
6.1 Marking
There shall be obvious marking on the outer packaging bag of PTA products, the content
of which may include: trademark, manufacturer name, factory address, standard number,
product name, production date or batch number, grade and net content.
6.2 Packaging