1 Scope
This part of GB/T 3682 specifies two procedures for the determination of the melt mass-flow rate (MFR) and the melt volume-flow rate (MVR) of thermoplastic materials under specified conditions of temperature and load. Procedure A is a mass-measurement method. Procedure B is a displacement-measurement method. Normally, the test conditions for measurement of melt flow rate are specified in the material standard with a reference to this part. The test conditions normally used for thermoplastics are listed in Annex A.
The MVR is particularly useful when comparing materials of different filler content and when comparing filled with unfilled thermoplastics. The MFR can be determined from MVR measurements, or vice versa, provided the melt density at the test temperature is known.
This part is also possibly applicable to thermoplastics for which the rheological behavior is affected during the measurement by phenomena such as hydrolysis (chain scission), condensation and cross- linking, but only if the effect is limited in extent and only if the repeatability and reproducibility are within an acceptable range.
For materials which show significantly affected rheological behavior during testing, this Part is not appropriate. In such cases, GB/T 3682.2 applies.
Note: The rates of shear in these methods are much smaller than those used under normal conditions of processing, and therefore it is possible that data obtained by these methods for various thermoplastics will not always correlate with their behavior during processing. Methods A and B are used primarily in quality control.
2 Normative references
The following referenced documents are indispensable for the application of this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced documents (including any amendments) applies.
GB/T 3505-2009 Geometrical product specifications (GPS) — Surface texture: Profile method — Terms definitions and surface texture parameters (ISO 4287:1997, IDT)
GB/T 3682.2-2018 Plastics — Determination of the melt mass flow rate (MFR) and melt volume-flow rate (MVR) of thermoplastics — Part 2: Method for materials sensitive to time-temperature history and/or moisture (ISO 1133-2:2011, MOD)
GB/T 4340.1-2009 Metallic materials — Vickers hardness test — Part 1: Test method (ISO 6507-1, MOD)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
melt mass-flow rate
MFR
rate of extrusion of a molten resin through a die of specified length and diameter under prescribed conditions of temperature, load and piston position; the rate being determined as the mass extruded over a specified time, and expressed in units of grams per 10 min (g/10 min)
Note: Alternative units accepted by SD are decigrams per minute, where 1 g/10 min is equivalent to 1 dg/min.
3.2
melt volume-flow rate
MVR
rate of extrusion of a molten resin through a die of specified length and diameter under prescribed conditions of temperature, load and piston position; the rate being determined as the mass extruded over a specified time, and expressed in units of cubic centimeters per 10min (cm3/10min)
3.3
load
combined mass of the mass of the piston and the added weight, or weights, as specified by the conditions of the test, in kilogram
3.4
preformed compacted charge
test sample prepared as a compressed charge of polymer sample
Note: In order to introduce samples quickly into the bore of the cylinder and to ensure void-free extrudate, it may be necessary to preform samples originally in the form of, for example, powders or flakes into a compacted charge.
Foreword i
Introduction iv
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Apparatus
6 Test sample
7 Temperature verification, cleaning and maintenance of the apparatus
8 Procedure A: mass-measurement method
9 Procedure B: displacement-measurement method
10 Flow rate ratio
11 Precision
12 Test report
Annex A (Normative) Test conditions for MFR and MVR determinations
Annex B (Informative) Conditions for the determination of the melt flow rate specified in relevant thermoplastics materials standards
Annex C (Informative) Device and procedure for preforming a compacted charge of material by compression
Annex D (Informative) Precision data for polypropylene obtained from an intercomparison of MFR and MVR testing in ISO 1133-1:2011
Bibliography
