Testing methods of fiber grade polyester (PET) chip
WARNING — Phenol, tetrachloroethane, dichlorobenzene, o-cresol, methanol and other similar solvents used in the tests are toxic, so measures shall be taken to prevent them from contacting the skin or being inhaled; sulfuric acid, hydrochloric acid, hydrogen peroxide and other similar reagents are highly corrosive, so measures shall be taken to prevent them from contacting the skin. The operator shall take proper safety and protection measures. During operation of gas chromatography, the detector does not ignite; it is strictly forbidden to start hydrogen needle valve in case of explosion due to leakage of hydrogen.
1 Scope
This standard specifies the testing methods for the analysis items of fiber grade polyester chip (PET).
This standard is applicable to the PET chips made of terephthalic acid and ethylene glycol; other functional polyester may make reference to this standard.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 601 Chemical reagent - Preparations of reference titration solutions
GB/T 603 Chemical reagent - Preparations of reagent solutions for use in test methods
GB/T 4146 (all parts) Textiles - Man-made fibers
GB/T 6283 Chemical products - Determination of water Karl Fischer method (general method)
GB/T 6678 General principles for sampling chemical products
GB/T 6682 Water for analytical laboratory use - Specification and test methods
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
ISO 3105 Glass capillary kinematic viscometers - Specifications and operating instructions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 4146 (all parts) and the following apply.
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3.1
bright polyester (PET) chip
polyester chip (PET) not subject to matting treatment
3.2
semi-dull polyester (PET) chip
polyester (PET) chip with titanium dioxide content greater than 0.20% and less than or equal to 0.50% (mass fraction)
3.3
full dull polyester (PET) chip
polyester (PET) chip with titanium dioxide content greater than or equal to 1.50% (mass fraction)
3.4
agglomerate particle
particle greater than or equal to 10 μm in PET chip
3.5
irregular chip
polyester chips (PET) with length longer than or equal to four times that of normal chip; with thickness, width or diameter greater than or equal to twice that of normal chip; with size less than 1/4 of conventional particle (or specified size); and of irregular shape
4 General principles for testing
4.1 Sampling
Laboratory sample in the batch sample is implemented according to GB/T 6678 and the specimen mass shall not be less than 0.5 kg.
4.2 General requirements
For the purpose of this standard, unless otherwise specified, all the reagents and water used refer to analytical reagents and Grade 3 water specified in GB/T 6682.
Unless otherwise specified, the standard volumetric solutions, preparations and products required for this standard shall be prepared according to the requirements of GB/T 601 and GB/T 603.
5 Testing methods
5.1 Testing method of intrinsic viscosity
5.1.1 Method A (capillary viscometer method)
5.1.1.1 Method principle
Determine flow time of 25°C solvent and PET solution at a concentration of 0.005 g/mL, and calculate its intrinsic viscosity according to measured flow time and solution concentration of the specimen. 1B may be selected for capillary viscometer until the kinetic energy correction item of viscometer is not taken into consideration.
5.1.1.2 Apparatus and equipment
5.1.1.2.1 Thermostatic bath: the test temperature is controlled at (25.00±0.05)°C.
5.1.1.2.2 Ubbelohde viscometer: the suspended level Ubbelohde viscometer as specified in ISO 3105 (see Figure 1); model: 1B. It is also allowed to use other types of viscometers stated in ISO 3105 that shall have equal determination results with the above-said Ubbelohde viscometer. Ubbelohde viscometer shall be adopted in dispute.
5.1.1.2.3 Conical flask with stopper: 100 mL.
5.1.1.2.4 Pipette or liquid fillers: 25 mL.
5.1.1.2.5 Balance: with precision of 0.1 mg.
5.1.1.2.6 Filter: 70 μm ~ 120 μm stainless steel cloth or corresponding sand core funnel.
5.1.1.2.7 Timer: with precision of 0.01 s.
5.1.1.2.8 Heating unit: the temperature is controlled with an accuracy of 2°C.
5.1.1.2.9 Vacuum drying oven: the pressure is less than 133.3 Pa and the temperature is controlled at (105±5)°C, .
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 General principles for testing
4.1 Sampling
4.2 General requirements
5 Testing methods
5.1 Testing method of intrinsic viscosity
5.2 Testing method of diethylene glycol
5.3 Testing method of melting point
5.4 Testing method of terminal carboxyl group
5.5 Testing method of chroma
5.6 Testing method of agglomerate particle
5.7 Testing method of moisture
5.8 Testing method of powder dust and irregular chip
5.9 Testing method of titanium dioxide content
5.10 Testing method of ash
5.11 Testing method of iron content
5.12 Test report
Annex A (Informative) Numerical relationship between two test methods for the intrinsic viscosity of solvents with different ratios
Annex B (Information Appendix) Recommended specification for diethylene glycol test reaction tube
