ISO 1133 Plastics - Determination of Melt Mass Flow Rate (MFR) and Melt Volume Flow Rate (MVR) of Thermoplastics

Material Testing

ISO 1133 Plastics - Determination of Melt Mass Flow Rate (MFR) and Melt Volume Flow Rate (MVR) of Thermoplastics

The ISO 1133 standard, developed by the International Standards Organization (ISO), specifies two procedures for determining the melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastic materials under certain temperature and load conditions. Procedure A is a mass measurement method. Procedure B is a displacement measurement method.

ISO 1133 Plastics - Determination of Melt Mass Flow Rate (MFR) and Melt Volume Flow Rate (MVR) of Thermoplastics

Normally, test conditions for melt flow rate measurement are specified in the material standard with reference to this International Standard. The test conditions normally used for thermoplastics are listed separately.

The MVR will be particularly useful when comparing materials with different filler content and when comparing filled versus unfilled thermoplastics. MFR can be determined from MVR measurements provided the melt density at test temperature and pressure is known.

These methods are in principle also applicable to thermoplastics if the rheological behavior during measurement is affected by events such as hydrolysis, condensation or crosslinking, but if the extent of the effect is limited and only if the repeatability and reproducibility are within an acceptable range.

These methods are not suitable for materials that exhibit significantly affected rheological behavior during testing. In such cases, it is recommended to use the viscosity number in the dilute solution determined according to the relevant part of ISO 1628 for characterization purposes.

The shear rates in these methods are much smaller than those used under normal processing conditions, and therefore the data obtained by these methods for various thermoplastics may not always correlate with their behavior during processing. Both methods are primarily used in quality control.

The melt mass flow rate (MFR) and melt volume flow rate (MVR) are determined by extruding the molten material from the barrel of a plastometer under preset temperature and load conditions. For the melt mass flow rate, the timed extrudate
portions are weighed and the extrudate rate is calculated and recorded in g/10 min. For the melt volume-flow rate, the distance the piston moves in a given time, or the time it takes for the piston to move a specified distance, is measured to produce data in cm3/10 min. If the density of the material is known under the test conditions, the melt volume flow rate can be converted to the melt mass flow rate and vice versa.

Extrusion Plastometer

The basic apparatus includes an extrusion plastometer operating at a constant temperature. Thermoplastic material in a vertical cylinder is extruded from a die by a piston loaded with a known weight. The device consists of the following basic parts.

The roller is fixed in the vertical position (see 5.1.5). The cylinder shall be made of a material resistant to wear and corrosion up to the maximum temperature of the heating system, and the finish of the surface, properties and dimensions of the tested material.
will not be affected. For certain materials it may be necessary to measure at temperatures up to 450 °C. The length of the cylinder will be between 115 mm and 180 mm and the inner diameter will be 9,550 mm ± 0,025 mm. The bottom of the roller will be thermally insulated with the exposed metal area less than 4 cm2, and it is recommended to use an insulating material such as Al2O3, ceramic fiber or other suitable material to prevent sticking.

The hole must be hardened to a Vickers hardness of at least 500 (HV 5 to HV 100) and produced with a technique that produces a surface roughness of Ra (arithmetic mean deviation) = lower. 0,25 µm. If necessary, a piston guide will be provided to keep friction caused by piston misalignment to a minimum.

Piston with working length at least as long as the cylinder. The piston shall be made of a material resistant to wear and corrosion up to the maximum temperature of the heating system, and its properties and dimensions shall not be affected by the material tested. The piston shall have a head length of 6,35 mm ± 0,10 mm. The diameter of the head should be 0,075 mm ± 0,010 mm less than the inside diameter of the cylinder. The sharp edge of the upper edge will be removed. Above the head, the piston will be loosened up to 9 mm in diameter. A stud can be added to the top of the piston to support a removable weight, but the piston must be thermally insulated from the weight. Two thin circular reference marks along the piston rod
It shall be drawn at intervals of 30 mm and positioned so that it is flush with the upper part of the upper cylinder when the distance between the lower edge of the piston head and the upper part of the die is 20.

These circular marks on the piston are used as reference points during measurements. To ensure satisfactory operation of the device, the cylinder and piston head must be made of materials of different hardness. Making the cylinder from a harder material is suitable for ease of maintenance and renewal.

The piston can be hollow or solid. In tests with very low loads, the piston may need to be hollow, otherwise it may not be possible to achieve the lowest prescribed load. When the test is carried out with higher loads, a guided solid piston or a hollow piston should be used.

EUROLAB, with its more than 25 years of experience, state-of-the-art accredited laboratories and expert team, helps you get precise and fast results. Among the services provided by our organization within the framework of material testing services, there are also ISO 1133 standard tests.

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