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|Product Name:||Melt Flow Index Tester||Test Result:||MFR MVR|
|Maximum Weight:||21600g||Standard:||ASTM D3346|
Melt Flow Index Tester Flow Rates for Poly(Vinyl Chloride) with Molecular Structural Implications ASTM D3346 MFI452
The melt mass-flow rate (MFR) and the melt volume-flow rate (MVR) are determined by extruding molten
material from the barrel of a plastometer under preset conditions of temperature and load. For melt mass-flow rate, timed segments of the extrudate are weighed and the extrudate rate is calculated in g/10 min and
recorded. For melt volume-flow rate, the distance that the piston moves in a specified time or the time required for the piston to move a specified distance is measured to generate data in cm3/10 min. Melt volume-flow rate may be converted to melt mass-flow rate, or vice-versa, if the density of the material is known under the conditions of the test.
Standard: ASTM D3346
Standard Test Method for Flow Rates for Poly(Vinyl Chloride) with Molecular Structural Implications
This test method is an extension of Test Method D 1238 specific to the measurement of flow rates of poly(vinylchloride) (PVC) compounds while detecting and controlling various polymer instabilities associated with the flow rate.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
NOTE —There is no similar or equivalent ISO standard.
D 883 Terminology Relating to Plastics
D 1238 Test Method for Flow Rates of Thermoplastics by Extrusion Plastometer
D 3835 Test Method for Rheological Properties of Thermoplastics with a Capillary Rheometer
E 177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
Summary of Test Method
In order to test a wide variation of flow rates covering semirigid as well as nonrigid PVC compounds, the following standard conditions are used:
Temperature 175°C (347°F)
Total load on piston 20 000 g
Approximate pressure 2758 kPa (400 psi)
Charge 2.15±0.05 g
Plugged orifice with 120° entrance angle
The lower temperature (relative to 190°C) is chosen to minimize thermal decomposition, maximize sensitivity of the flow rate to structural changes in the PVC compound, and to allow a wide latitude of useful conditions associated with the load on the piston.
Modern extrusion plastometers have been redesigned to accomodate much higher loads. Current research for multiweight testing has reached levels of 50 kg and these are particularly good for rigid PVC. Previously, flow rates for rigid PVC were limited to 190°C. Recent research has shown that rigid PVC can be run at 150°C and 50 kg loads. This weight is effective for all semirigid PVC and even some nonrigid
compounds. For flow rates in excess of 10 g/10 min (1000mg/min), lower weights are used, for example, color concentrates sed in PVC extrusion may have flow rates in excess of 00 g/10 min (10 000 mg/min) and will require a 5-kg load on the piston.
When the flow rates become very small as in the case of the stiffest semirigid containing 25 parts of plasticizer (flow rates below 15 mg/min), it may be desirable to use the die (flat entry 8 mm (0.315 in.) long) in Test Method D 1238. The flow s so slow that little rheological instability exists. By changing he die, approximately a tenfold increase in flow is achieved.
The charge size is important. Many PVC compounds are elastic in nature, causing a severe loss in pressure from the bottom of the piston through the material to the orifice of the die. Evidence indicates that the force to extrude may be reduced by as much as 67 % using a 9-g charge and 4.14 MPa (600 psi) on the piston.
The plugged orifice should be used in all PVC compound work since the amount of charge is limited and since the plugging for various times has been observed to give significant variations in the flow rate.
Plastometer—The apparatus is identical to that used in Test Method D 1238 except for the die. An alternative thermoregulator is suggested for improved temperature control.
Die:The die is approximately three times as long as the one used in Test Method D 1238, a major factor in controlling any rheological instability in the polymer. If instability still occurs, particularly at high flow rates, dies 2 in. or longer can be used to improve the L/D ratio. The dimensions of the regular die are shown in Fig. 1.
Thermoregulator—Although a thermoregulator identical to that used in Test Method D 1238 may be used (provided it regulates to 175 6 0.1°C), a unit5 coupled with a 90° angle thermometer, divided into 0.1°C is suggested for improved reproducibility. Most regulators designed for Test Method D 1238 cannot control better than 60.2°C. The sensitivity of this test method is illustrated by the fact that a 19 % change in
flow rate is observed on a typical PVC compound with a 1°C change in temperatures.
Thermometer, measuring the standard temperature,should rest on the top of the orifice to conform with conditions in accordance with Test Method D 1238 (1⁄2 in. above the shorter orifice).
Report the following information:
PVC flow rate, stating the date, any process information,sample identification, weight on the piston, and die,
Percent PVC instability,
PVC swelling instability, and
Any change in color, referenced to the time at which it occurred.
This type of melt flow indexer is a high precise melt testing instrument for the measurement of melt flow rate (MFR)/(MI) or melt volume rate (MVR) in quality control and research applications. The testing result can distinguish the viscous flow performance of thermoplastic material by the model MFI452 showing its advantage in the following industries: factories, products quality testing station, scientific and research institutes, and concerned industries.
Test standard: Comply with ISO1133, ASTM D1238, ASTM D3364, BS2782, DIN53735, JIS K7210
• Two digital display control panels with membrane covered buttons, comfortable touching, intuitive operating and real-time data displaying.
• Test method (MFR/MVR) can be pre-selected by the control panel, and test can be conducted automatically as preset program. And there is a friendly prompt by hum to alarm the coming end of each test step in the whole test process.
• The OMRON E5AZ temperature control system is configured with two groups of platinum resistor temperature transducers and one group of the two is used as spare part which makes a high reliability. And the PID algorithm is used to adjust the temperature and compensate the influence of temperature caused by the environment or undulation of power to ensure a good stability.
• Automatic cut-off device, driven by motor, small size, good flexibility. It can carry out the automatic timing cut-off, jog cut-off and manual cut-off as the need of the customers.
• Built-in micro-printer. When the Test is completed, the results will be printed on scrip clearly only by pressing on the “Print” button.
• The displacement of the piston rod is exactly measured by the infrared sensor.
• The piston rod and the filling canister are all made of nitriding steel with high rigidity and strong corrosion resistance.
• A set of elaborately designed accessories to provide a convenient operation and maintenance.
|Temperature variation in 4 hours||℃||≤0.5|
|Temperature variation with distance at between
10 mm and 50 mm above the die surface
|Interval of temperature recovering after changing testing samples||minute||≤4|
|Resolution of timing||second||0.1~1|
|Inner diameter of die||mm||Φ2.095±0.005|
|Inner diameter of filling canister||mm||Φ9.550±0.025|
|Possible Combination of the Standard Weights||g||325, 1200, 2160, 3800, 5000|
|Power Supply||220V±10%, AC, 50HZ, 3A|
|Cut-off device||Automatic/Jog/Manual cut-off|
|Main machine (with built-in control panel, micro-printer, cylinder heater, cutting knife)||1 set|
|Piston Rod (with a stud, a piston guide)||1 set|
|Standard die of Φ2.095±0.005mm||1 set|
|T-Shape Weights tray||1 set|
|5000g load Weights of 875g, 960g, 1200g, 1640g||1 set for each|
|Die clean rod, cylinder Clean Rod, packing rod, filling funnel, feeder, wooden handle knife, cut-off blade for spare use||1 set for each|
|Load (g)||Combination of dead weight (g)|
|325||T-shape weight tray and the weight of piston|