GB/T 3682-2000 Determination of mass flow rate and melt volume flow rate of thermoplastic melts
Some standard content:
GB/T 3682—2000
Foreword
This standard is equivalent to the international standard IS01133:1997 "Plastics-Determination of melt mass flow rate and melt volume flow rate of thermoplastics". This standard is completely consistent with ISO1133:1997 in terms of technical content, and has the following differences in editing: This standard has fewer references than ISO1133:1997, but the contents not listed in this standard do not affect the implementation of this standard.
A small amount of editorial changes have been made in accordance with relevant regulations of my country. The previous version of this standard is the national standard GB/T3682--1983 "Test method for melt flow rate of thermoplastics". Compared with the previous version, there are the following main differences:
- The name of the standard has been changed;
"referenced standards" have been added;
The test conditions have been taken as "suggestive appendixes", and some additions and deletions have been made;
The automatic test of the mass flow rate of thermoplastic melts and the determination of the melt volume flow rate have been added. This standard will replace GB/T3682-1983 from the date of implementation. Appendix A of this standard is the appendix of the standard, and Appendix B is the suggestive appendix. This standard is proposed by the State Bureau of Petroleum and Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Plastic Resin Products Branch of the National Technical Committee for Plastic Standardization (TC15/SC4). The responsible drafting units of this standard are: Shanghai Import and Export Commodity Inspection Bureau, Shanghai Plastics Research Institute. Participating drafting units of this standard are: Shengguang Chemical Research Institute, Beijing Yanshan Resin Application Research Institute, Shanghai Petrochemical Co., Ltd. Plastic Factory, Jilin University Science and Education Instrument Factory, Chengde Testing Machine Co., Ltd. The main drafters of this standard are: Li Jianghai, Shen Hong, Shu Xingdao, Luo Taiwei, Jiang Haining, Tai Yuxing, Zhao Lingyun. This standard was first published in 1983.
GB/T3682—2000
ISO Foreword
The International Organization for Standardization (ISO) is a worldwide federation of national standardization bodies (ISO member bodies). The work of formulating international standards is usually carried out by ISO technical committees. Any member body interested in a project established by a technical committee has the right to send representatives to the technical committee, and governmental or non-governmental international organizations associated with ISO may also participate in its work. ISO works closely with the International Electrotechnical Commission (IEC) on all subjects of electrotechnical standardization. Draft international standards adopted by the technical committee are distributed to member bodies for voting before being accepted as international standards by the ISO Council. According to the ISO Constitution, at least 75% of the member bodies must vote in favor for the vote to be valid. International Standard ISO1133 was formulated by ISO/TC61 Plastics Technical Committee, SC5 Physical and Chemical Properties Technical Committee. This third edition is a technical revision that cancels and replaces the second edition (ISO1133:1991): the flow rate ratio (FRR) is added to make the provisions further clear.
Appendix A is a standard appendix, and Appendix B is an informative appendix. 1 Scope
National Standard of the People's Republic of China
Determination of the melt mass-flow rate (MFR)and the melt volume-flow rate (MVR) of thermoplasticsGB/T3682—2000
idtISo1133:1997
Replaces GB/T3682-1983
1.1 This standard specifies the method for determining the melt mass-flow rate (MFR) and the melt volume-flow rate (MVR) of thermoplastics under specified temperature and load conditions. Generally, the test conditions for determining the melt flow rate are specified by the material standards referenced in this standard. General test conditions for thermoplastics are listed in Annex A and Annex B. The melt volume flow rate is very useful when comparing filled and unfilled thermoplastics. If the melt density at the test temperature is known, the melt flow rate can be determined using an automatic measuring device. This method is not applicable to thermoplastics whose rheological behavior is affected by hydrolysis, polycondensation or crosslinking. 1.2 The melt mass flow rate and melt volume flow rate of thermoplastics are related to the shear rate. The shear rate in this test is much smaller than the shear rate during actual processing. Therefore, the data of various thermoplastics obtained by this method are not necessarily related to their performance in actual use. Both methods are useful in quality control. 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. When this standard was published, the versions shown were valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T1031-1995 Surface roughness parameters and their values (neqISO468:1982) 3 Instruments
3.1 Main instruments
3.1.1 This instrument is basically an extrusion plastic tester operated under set temperature conditions. The basic structure is shown in Figure 1. The thermoplastic material is placed in a vertical barrel and extruded through a standard die under the action of a loaded piston. The instrument consists of the following necessary components: 3.1.2 Slug: Fixed in a vertical position, made of a material that can resist wear and corrosion at the highest temperature reached by the heating system, and does not react with the sample being tested. For some special materials, the test temperature is required to reach 450°C. The barrel length is 115~180mm, and the inner diameter is 9.550mm±0.025mm. The bottom insulation should make the metal exposed area less than 4cm2. It is recommended to use aluminum oxide ceramic fiber or other suitable materials as the bottom insulation material to avoid adhesion of the extrudate. The hardness of the inner bore of the cylinder should be not less than 500 (HV5HV100) Vickers hardness; the surface roughness Ra (arithmetic mean) should be less than 0.25um (GB/T1031-1995); if necessary, a piston guide sleeve can be installed to reduce the friction caused by piston misalignment, so that the error between the actual load and the nominal load is not more than ±0.5%. 3.1.3 Steel piston: Its working length should not be shorter than the length of the cylinder, and it should have a piston head with a length of 6.35mm ±0.10mm. The diameter of the piston head should be 0.075mm ±0.010mm smaller than the inner diameter of the cylinder, the upper edge should be smooth, and the piston rod diameter above the piston head should be reduced to about 9mm. A columnar bolt can be added to the top of the piston to support the removable load magnetic code, but the piston needs to be insulated from the load. Two thin circular reference lines 30 mm apart should be engraved on the piston rod. When the bottom of the piston head is 20 mm away from the upper part of the die, the upper line is flush with the mouth of the material cylinder. These two lines are used as reference points for measurement (see 6.3 and 7.4). In order to ensure the good operation of the instrument, the material cylinder and the piston should be made of materials with different hardness. For the convenience of maintenance and replacement, the material cylinder should be made of harder material than the piston. The piston can be hollow or solid. When using a small load test, the piston should be hollow, otherwise the specified minimum load may not be reached. When using a larger load test, a hollow piston is not suitable because the larger load may cause it to deform. A solid piston or a hollow piston with a piston guide should be used. If the latter is used, since this piston rod is longer than the usual piston rod, it should be ensured that the heat loss along the piston does not change the test temperature of the material. 2
1 Unloadable load: 2-insulation; 3-upper reference mark; 4-insulation; 5-lower reference mark,
6-steel cylinder; 7-die, 8-insulation plate, 9-die baffle; 10-control thermometer Figure 1 Typical device for determining melt flow rate 3.1.4 Temperature control system
For any set cylinder temperature, the temperature in the entire range from the die mouth to the allowable feeding height should be effectively controlled during the test, and the difference in temperature measured at the cylinder wall should not exceed the range specified in Table 1. Note: The cylinder wall temperature can be measured by a platinum thermocouple thermometer installed in the wall. If the instrument is not equipped with such a device, it can be measured in the melt at a certain distance from the cylinder wall, depending on the type of thermometer used.
The temperature control system should allow the test temperature to be set in intervals of 1°C or less. Table 1 Maximum tolerance of temperature variation with distance and time Test temperature 6, ℃
200300
With distance
Temperature tolerance, ℃
With time
3.1.5 Mouth die, made of tungsten carbide or high hardness steel; length 8.000mm ± 0.025mm; inner hole should be round and straight, inner diameter is 2.095mm and evenly hooked, and the tolerance at any position should be within ± 0.005mm. The inner hole hardness should not be less than Vickers hardness 500 (HV5~HV100), and the surface roughness. Ra (arithmetic mean) should be less than 0.25μm (GB/T1031-1995). The die cannot protrude from the bottom of the barrel (see Figure 1), and its inner hole must be installed coaxially with the inner hole of the barrel. 3.1.6 Method for installing and keeping the barrel perfectly vertical A two-way bubble level and adjustable instrument feet placed perpendicular to the axis of the barrel are suitable for keeping the barrel vertical. Note: This can prevent the piston from being subjected to excessive friction or bending under heavy loads. A simulated piston with a level on the upper end can be used to check whether the barrel is completely vertical.
GB/T 3682-2000
3.1.7 The removable load is located on the top of the piston and consists of a set of adjustable weights. The mass of these weights combined with the piston can be adjusted to the selected nominal load with an accuracy of 0.5%. For larger loads, a mechanical loading load device can be selected. 3.2 Accessories
3.2.1 General accessories
3.2.1.1 Device for loading the sample into the barrel, a loading rod made of non-abrasive material. 3.2.1.2 Cleaning device.
3.2.1.3 Mercury-in-glass thermometer (calibration thermometer) or other temperature measuring device, which can accurately calibrate the temperature to ±0.5°C when the temperature control system is calibrated according to the temperature and immersion conditions specified in 5.1. 3.2.2 Accessories used in method A
3.2.2.1 Cutting tool, used to cut the extruded sample, a sharp-edged scraper can be used. 3.2.2.2 Stopwatch, accurate to ±0.1 s.
3.2.2.3 Balance, accurate to ±0.5 mg. 3.2.3 Accessories used in method B
Measuring device: can automatically measure the distance and time of piston movement. 4 Test specimens
4.1 The test specimens may be of any shape, such as powders, granules or film fragments, as long as they can be placed in the barrel. Note: Some powdered materials will not be able to be tested in small strips without bubbles if they are not pre-pressed. 4.2 Before testing, the material should be conditioned in accordance with the material specification and stabilized if necessary. 5 Temperature calibration, cleaning and maintenance of the instrument
5.1 Calibration of the temperature control system
5.1.1 The accuracy of the temperature control system (3.1.4) should be calibrated regularly. To do this, first adjust the temperature control system so that the barrel temperature indicated by the control thermometer is constant at the required temperature. Preheat the calibration thermometer (3.2.1.3) to the same temperature, and then add some of the test material or alternative material (see 5.1.2) into the barrel in the same manner as in the test (see 6.2). After the material is fully loaded, wait for 4 minutes, insert the calibration thermometer into the sample and immerse it in the material until the top of the mercury ball is 10mm away from the upper surface of the die. After another 4 to 10 minutes, use the difference between the calibration thermometer and the control thermometer reading to correct the temperature displayed by the control thermometer. The temperature of multiple points should also be calibrated along the material line, and the sample temperature should be measured at intervals of 10mm until the point 60mm away from the upper surface of the die. The maximum deviation of the two extreme values should comply with the provisions of Table 1. 5.1.2 The material selected for temperature calibration must be able to flow fully so that the ball of the mercury thermometer will not be damaged by excessive force when inserted. When calibrating the temperature, the material with a melt flow rate (MFR) greater than 45g/10min (2.16kg load) is suitable. If a material is used to replace the more viscous test material during temperature calibration, the thermal conductivity of the replacement material should be consistent with the test material so that they have similar thermal behavior. The material added during temperature calibration should be able to allow the calibration thermometer rod to have enough length to be inserted into it so that the measurement is accurate. This can be determined by removing the calibrated thermometer and checking the height of the material adhered to the thermometer stem. 5.2 Cleaning of the apparatus
After each test, the apparatus should be thoroughly cleaned. The barrel can be cleaned with a cloth, the piston should be cleaned with a cloth while hot, and the die can be cleaned with a tight-fitting brass reamer or wooden dowel. It can also be cleaned by thermal cracking in a nitrogen atmosphere at about 550 °C. However, abrasives and similar materials that may damage the barrel, piston and die surfaces should not be used. It must be noted that the cleaning procedure used does not affect the die size and surface roughness. If solvents are used to clean the barrel, care should be taken that the effect on the next test is negligible. Note: It is recommended that the insulation board and die baffle installed as shown in Figure 1 be removed at short intervals for commonly used instruments, for example once a week, and the barrel can be thoroughly cleaned.
6 Method A
6.1 Cleaning the apparatus (see 5.2). Before starting a set of tests, ensure that the barrel (3.1.2) is kept at the selected temperature for not less than 15 min. 7
GB/T3682--2000
6.2 According to the estimated flow rate, load 3~~8g of sample into the feed tube (see Table 2). When loading, use the hand-held loading rod (3.2.1.1) to compact the sample. For materials sensitive to oxidative degradation, avoid contact with air as much as possible during loading, and complete the loading process within 1 minute. According to the flow rate of the material, place the loaded or unloaded piston into the feed tube. If the melt flow rate of the material is higher than 10g/10min, the loss of sample during the preheating process cannot be ignored. In this case, use an unloaded or lightly loaded piston during preheating until the end of the 4min preheating period and then change the load to the required load. When the melt flow rate is very high, a die plug is required. Table 2
Melt flow rate\, g/10min
Sample mass in the material sheet\, g
Extrudate cut-off time interval, s
1) If the value measured in this test is less than 0.1 g/10min or greater than 100 g/10min, it is recommended not to measure the melt flow rate. 2) When the material density is greater than 1.0 g/cm2, it may be necessary to increase the sample mass. 3) When determining materials with an MFR greater than 25 g/10min, in order to obtain sufficient reproducibility, it may be necessary to automatically control and measure the cut-off time interval of less than 0.1 s or use method B6.3. 4 minutes after the filling is completed, the temperature should be restored to the selected temperature. If there was no load or insufficient load, the selected load should be added to the piston at this time. Let the piston descend under the action of gravity until a thin strip without bubbles is extruded. Depending on the actual viscosity of the material, this phenomenon may occur before or after the load is added. This operation time should not exceed 1 minute. Cut the extrudate with the cutting tool (3.2.2.1) and discard it. Then let the loaded piston continue to descend under the action of gravity. When the lower mark reaches the top of the cylinder, start timing with the stopwatch (3.2.2.2), and at the same time cut the extrudate with the cutting tool and discard it. Then, collect the extrudate segments at a certain time interval to determine the extrusion rate. The time interval for cutting depends on the melt flow rate. The length of each segment should not be less than 10 mm, preferably 10-20 mm. The standard time interval is exempted from Table 2. For materials with small MFR (and MVR) and (or) high die swell, it may be difficult to obtain a segment length of not less than 10 mm within the maximum segment interval of 240 s. In this case, method A can only be used if the mass of each segment obtained within 240 s reaches more than 0.04, otherwise method B should be used. Stop cutting when the upper mark of the piston rod reaches the top of the cylinder. Discard the segments with visible bubbles. After cooling, weigh the remaining cut pieces (at least 3) one by one to an accuracy of 1 mg and calculate their average mass. If the difference between the maximum and minimum values in the individual weighing values exceeds 15% of the average value, discard the data set and repeat the test with new samples. The time from charging to cutting the last sample should not exceed 25 min. 6.4 Calculate the melt mass flow rate (MFR) value in g/10 min using formula (1): MFR(3,mnom) =
tref · mwwW.bzxz.Net
Where: test temperature, °C;
-nominal load, kg;
m-average mass of the cut pieces, 8,
tref -reference time (10 min), s (600 s); -time interval between cuts, s.
Represent the result with two significant figures and record the test conditions used (e.g. 190/2.16). 8
７ Method B
7.1 Principle
GB/T3682-2000
The melt mass flow rate (MFR) and melt volume flow rate (MVR) are determined using one of the following two principles: a) Determine the distance the piston moves within a specified time; b) Determine the time taken by the piston to move a specified distance. 7.2 Optimum measurement accuracy
In order to make the determination of MFR between 0.1 and 50 g/10 min or MVR between 0.1 and 50 cm2/10 min reproducible, the piston displacement measurement should be accurate to ±0.1 mm, the time measurement should be accurate to 0.1 s. 7.3 Operation preparation
Perform according to the provisions of 6.1 to 6.3 (to the end of the paragraph) in Method A. 7.4. Measurement
7.4.1 When the lower mark reaches the top surface of the barrel, start automatic measurement. 7.4.2 Perform measurement as follows:
a) If the principle of 7.1a) is adopted, measure the distance the piston moves within a predetermined time; b) If the principle of 7.1b) is adopted, measure the time required for the piston to move a specified distance. Stop the measurement when the mark on the piston rod reaches the top surface of the barrel. 7.4.3 The time from the start of material addition to the last data measurement shall not exceed 25 minutes. 7.5 Expression of results
7.5.1 Calculate the melt volume flow rate (MVR) in cm/10 min using formula (2): A·trer ·l-
MVR(0,mnom)-
where: ---test temperature, °C;
nominal load, kg;
A--average cross-sectional area of piston and cylinder (equal to 0.711 cm2), cm2; tref
reference time (10 min), s (600 s); 427
predetermined measuring time (see 7.4.2a) or the average value of individual measuring times (see 7.4.2b), s; --predetermined measuring distance traveled by the piston (see 7.4.2b) or the average value of individual measuring distances (see 7.4.2a), cm.
7.5.2 Calculate the melt mass flow rate (MFR) in g/10 min using formula (3): MFR(0,mnom):
where: ,mnom, A,tre,l and t are the same as in 7.5.1; 0
A· tref ·lp- 427l.p
The density of the melt at the test temperature is calculated using formula (4) in g/cm2; m
where m is the mass of the sample extruded when the piston moves 1 cm. 7.5.3 Express the result with two significant figures and record the test conditions used (e.g. 190/2.16). 8 Flow rate ratio (FRR)
The relationship between two MFR (or MVR) values is called the flow rate ratio, as shown in formula (5): FRR=
MFR(190/21.6)
MFR(190/2.16)
It is generally used to characterize the effect of the molecular weight distribution of a material on its rheological behavior. .(2)
（４）
GB/T 3682—2000
Note: The conditions used to determine the flow rate ratio are listed in the corresponding material standards. 9 Precision
When using this method to measure specific materials, factors that may reduce repeatability should be considered. These factors include: a) Changes in melt flow rate due to thermal degradation or cross-linking of the material during preheating or testing (powdered materials that require long preheating times are more sensitive to this effect. In some cases, stabilizers need to be added to reduce this change). b) For filled or reinforced materials, the distribution or orientation of the filler may affect the melt flow rate. The precision of this method cannot be determined because interlaboratory test data are not available. Because of the large number of materials involved, a single precision is not appropriate, but a coefficient of variation of ±10% can be expected. 10 Test report
The test report shall include the following parts: a) Reference to this standard;
b) A detailed description of the test specimen, including its physical shape when loaded into the cylinder; c) A detailed description of the conditioning;
d) A detailed description of the stabilization treatment (see 4.2); e) The temperature and load used in the test;
f) For method A, the cut mass and the cut time interval; for method B, the predetermined time or piston travel distance and the corresponding measured value of the piston travel distance or time taken; g) The melt mass flow rate, g/10 min; or the melt volume flow rate, cm/10 min. The result shall be expressed with two significant figures (when multiple values are obtained, all individual values shall be reported); h) report the flow rate ratio (FRR) when necessary; i) report any abnormal conditions of the test specimen, such as discoloration, stickiness, extrudate distortion or abnormal changes in melt flow rate; j) test date.
GB/T 3682--2000
Appendix A
(Standard Appendix)
Test conditions for determining melt flow rate
The test conditions used shall be specified by the corresponding material name or specification standard. Table A1 lists the test conditions that have been proven to be applicable. Table A1
Conditions (letter code)
Test temperature 6,℃
Nominal load (combination) maom, kg
Note: If test conditions not listed in this table are to be used in the future, for example, for new thermoplastic materials, only the loads and temperatures used in this table can be selected
Appendix B
(Suggestive Appendix)
Test conditions for thermoplastic materials
Table B1 lists the test conditions specified in the relevant standards. If necessary, other test conditions not listed can be used for certain special materials.
Conditions (letter code)
Test temperature 6, °C
Nominal load (combination) mnom, kg
ASA, ACS, AES
GB/T 3682—2000
Table B1 (end)
Conditions (letter code)
Test temperature 8, °C
Nominal load (combination) mnom, kg(2)
（４）
GB/T 3682—2000
Note: The conditions for determining the flow rate ratio are listed in the corresponding material standard. 9 Precision
When using this method to measure specific materials, factors that may reduce repeatability should be considered. These factors include: a) Changes in melt flow rate due to thermal degradation or cross-linking of the material during preheating or testing (powdered materials that require long preheating times are more sensitive to this effect. In some cases, stabilizers need to be added to reduce this change). b) For filled or reinforced materials, the distribution or orientation of the filler can affect the melt flow rate. Because inter-laboratory test data have not yet been obtained, the precision of this method cannot be determined. Because there are many materials involved, it is not appropriate to describe it with a single precision, but a coefficient of variation of ±10% can be expected. 10 Test report
The test report shall include the following parts: a) Reference to this standard;
b) Detailed description of the test specimen, including its physical shape when loaded into the cylinder; c) Detailed description of the conditioning;
d) Detailed description of the stabilization treatment (see 4.2); e) Temperature and load used in the test;
f) For method A, the cut mass and the time interval between cuts; for method B, the predetermined time or piston travel distance and the corresponding measured value of the piston travel distance or time taken; g) Melt mass flow rate, g/10 min; or melt volume flow rate, cm/10 min. The results shall be expressed to two significant figures (when multiple measurements are obtained, all individual measurements shall be reported); h) Flow rate ratio (FRR), if necessary; i) Report any abnormality of the test specimen, such as discoloration, stickiness, extrudate distortion, or abnormal changes in melt flow rate; j) Date of test.
GB/T 3682--2000
Appendix A
(Standard Appendix)
Test conditions for determining melt flow rate
The test conditions used shall be specified by the corresponding material naming or specification standards. Table A1 lists the test conditions that have been proven to be applicable. Table A1
Conditions (letter code)
Test temperature 6, ℃
Nominal load (combination) maom, kg
Note: If test conditions not listed in this table are to be used in the future, for example, for new thermoplastic materials, only the loads and temperatures used in this table can be selected
Appendix B
(Suggestive Appendix)
Test conditions for thermoplastic materials
Table B1 lists the test conditions specified in the relevant standards. If necessary, other test conditions not listed can be used for some special materials.
Conditions (letter code)
Test temperature 6, °C
Nominal load (combination) mnom, kg
ASA, ACS, AES
GB/T 3682—2000
Table B1 (end)
Conditions (letter code)
Test temperature 8, °C
Nominal load (combination) mnom, kg(2)
（４）
GB/T 3682—2000
Note: The conditions for determining the flow rate ratio are listed in the corresponding material standard. 9 Precision
When using this method to measure specific materials, factors that may reduce repeatability should be considered. These factors include: a) Changes in melt flow rate due to thermal degradation or cross-linking of the material during preheating or testing (powdered materials that require long preheating times are more sensitive to this effect. In some cases, stabilizers need to be added to reduce this change). b) For filled or reinforced materials, the distribution or orientation of the filler can affect the melt flow rate. Because inter-laboratory test data have not yet been obtained, the precision of this method cannot be determined. Because there are many materials involved, it is not appropriate to describe it with a single precision, but a coefficient of variation of ±10% can be expected. 10 Test report
The test report shall include the following parts: a) Reference to this standard;
b) Detailed description of the test specimen, including its physical shape when loaded into the cylinder; c) Detailed description of the conditioning;
d) Detailed description of the stabilization treatment (see 4.2); e) Temperature and load used in the test;
f) For method A, the cut mass and the time interval between cuts; for method B, the predetermined time or piston travel distance and the corresponding measured value of the piston travel distance or time taken; g) Melt mass flow rate, g/10 min; or melt volume flow rate, cm/10 min. The results shall be expressed to two significant figures (when multiple measurements are obtained, all individual measurements shall be reported); h) Flow rate ratio (FRR), if necessary; i) Report any abnormality of the test specimen, such as discoloration, stickiness, extrudate distortion, or abnormal changes in melt flow rate; j) Date of test.
GB/T 3682--2000
Appendix A
(Standard Appendix)
Test conditions for determining melt flow rate
The test conditions used shall be specified by the corresponding material naming or specification standards. Table A1 lists the test conditions that have been proven to be applicable. Table A1
Conditions (letter code)
Test temperature 6, ℃
Nominal load (combination) maom, kg
Note: If test conditions not listed in this table are to be used in the future, for example, for new thermoplastic materials, only the loads and temperatures used in this table can be selected
Appendix B
(Suggestive Appendix)
Test conditions for thermoplastic materials
Table B1 lists the test conditions specified in the relevant standards. If necessary, other test conditions not listed can be used for some special materials.
Conditions (letter code)
Test temperature 6, °C
Nominal load (combination) mnom, kg
ASA, ACS, AES
GB/T 3682—2000
Table B1 (end)
Conditions (letter code)
Test temperature 8, °C
Nominal load (combination) mnom, kg
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