Original standard number GB 7138-86 HG/T 2900-1997 Test method for bulk density of polytetrafluoroethylene resin HG/T2900-1997 Standard download decompression password: www.bzxz.net

HG/T2900-1997
This standard is equivalent to 13.2 of ASTMD1457-92 "Standard Specification for Polytetrafluoroethylene Molding and Extrusion Materials". The main differences between this standard and ASTMD1457 are: (1) This standard appropriately increases the number of times the resin is screened and prolongs the time for the resin to pass through the feeder mesh screen; (2) Since this standard has processed the feeder and the funnel into an assembled type, the two become a whole when used. Therefore, this standard changes "adjusting the distance from the feeder outlet to the top edge of the measuring cup" to "adjusting the distance from the funnel outlet to the top edge of the measuring cup". The previous version of this standard is GB/T7138-86 "Test Method for Apparent Density of Polytetrafluoroethylene Resin". Compared with the previous version, the foreword and scope are added, and the distance from the funnel outlet to the top edge of the measuring cup is corrected from *32mm+3mm to 38.1±3.2 mm\
White From the date of implementation of this standard, the original national standard GB/T7138--85 "Test method for apparent density of polytetrafluoroethylene resin" was proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Plastic Resin Product Sub-Technical Committee of the National Plastic Standardization Technical Committee (SC4). The responsible drafting unit of this standard is Shanghai San Ai Fu New Materials Co., Ltd. The main drafters of this standard are Ma Yujin and Zhou Aibao. ICS83. 080. 20
Registration No. 420--1997
Chemical Industry Standard of the People's Republic of China
Test method for bulk density of polytetrafluarocthylene resin1 Scope
This standard specifies the test method for bulk density of polytetrafluoroethylene resin, HG/T 2900 -- 1997
This standard is applicable to the determination of the bulk density of fluoroethylene resin produced by the separation method or the floating method. 2 Principle of the method
Measure the mass of 1L of resin under test conditions. 3 Instruments and devices
3.1 Electric vibrator
Motor power: 40W;
Motor speed: 2750r/min.
3.2 Feeder
3.2.1 Material: 0.5mm thick stainless steel plate; 3.2.2 Requirements: The outlet is smooth and equipped with a stainless steel mesh screen with a mesh diameter of 2.26mm 1. The mesh screen is located at the top 2/3 of the material. As shown in Figure 1,
Instructions:
1). ASTMD1457 stipulates that the US No. B mesh screen, that is, the diameter is 2.36mm. The Ministry of Chemical Industry of the People's Republic of China approved it on May 23, 1997 and implemented it on October 1, 1997.
HG/ T 2900 --1997
Stainless steel screen
Figure Feeder
3.3.1 Material: 0.5mm thick stainless steel plate, 3
3.3.2 Requirements: The funnel with baffle is fixedly assembled at the outlet of the feeder, as shown in [2. 12
3 Material: Stainless steel pot
G7T 290-185?
Figure 2 Tide bucket
3.4.2 Volume: 250mI±C.5mL, size as shown in 3. 13
3.5 Cup holder 2)
3.5.1 Material: brass or other metal materials. 3.5.2 Size: as shown in Figure 4.
Instructions for use:
HG/ T 2900 —1997
@61. 90±0.02
Φ57. 15± 0. 02
9g°±15
Figure 3 Fortress cup
Φ61. 96±0. 01
90° ±15
Figure 4 Cup holder
2] ASTMD1457 medium cup holder, no vents and overflow grids, 14
3.6 Scraper scale
Support 1 Material: stainless steel.
/T2900—1997
6.2 Requirements: The scraper should be fixed on the work stand. The scraper has a tooth pitch of 6 teeth and a 25mm pitch. The tooth depth is 1.6mm, and the thickness is 2.5mm. The tooth tip of the scraper is 0.8mm±0.1mm away from the end of the cup, as shown in Figure 5. 210
Q4×19 screw
Hexagonal screw
Figure 5 ScraperwwW.bzxz.Net
3.7 Working surface
In order to prevent the measuring cup and the leveler from vibrating, the feeder must be fixed on a workbench or wall shelf away from the neighboring area. 3.8 Balance
Weight: 0.1g
3.9 Stopwatch
4 Test conditions 3)
23r ±5t.
5 Operation steps
5.1 Place the sample under the test conditions for 2h
3.2 Weigh the mass of the cup on the balance (m,) with an accuracy of 0.1g.5.3 Start the vibrator with a feeder and sieve about 500mL of resin on the feeder mesh screen, repeat three times to break the agglomerates.
Note: The resin obtained by dispersion coagulation does not need to be sieved. 5.4 Adjust the distance between the full bucket outlet and the top edge of the pan cup to 38.1mm±3.2mm, and continuously add the sieved resin to the pan cup. Note:
3FASTMD1457 stipulates that the test conditions are 23C±2℃43ASTMD1457 stipulates that the test shrinkage is twice
5ASTM14ST stipulates the distance between the pre-cooling feeder outlet and the top edge of the pan cup.13
HG / T 2900 —1997
The feeder passes through the two sieves and controls the resin to fill the measuring cup within 20s~0s, so that the resin is piled up in the measuring cup in the shape of a small hill. After standing still for 15s, gently pull the cup holder over the scraper to avoid moving the resin and the cup before scraping. 5.5 Measure the mass of the measuring cup filled with resin (m2) on the balance, accurate to 0.1g. 6 Result expression
The volume density of polytetrafluoroethylene resin is calculated according to formula (1): p
Where: D--volume density, g/L;
m2--mass of the measuring cup filled with resin, g;
m,---mass of the measuring cup, gi||t t||V-volume of measuring cup, Q250L.
Test results are expressed as the arithmetic mean of 3 measurements, and the integer is taken for precision
The relative standard deviation of the volume density of tetrafluoroethylene resin is ±6g/L (95% confidence level).8 Test report
The test report should include the following contents:
Sample number and batch number;
Sampling date;
Test environment temperature;
Single measured value and arithmetic mean of volume density;
Test date and test personnel;
Adopting period:
6) ASTMI[457 stipulates that it is 20s~30s.
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