This standard specifies the acceptance requirements and methods for unsintered tape (i.e. raw tape) made of polytetrafluoroethylene dispersion resin by pressing and calendering without any additives. This standard is applicable to polytetrafluoroethylene raw tape used in sealing of crimped joints and in contact with strong oxidants and chemical explosives. QB/T 3628-1999 Polytetrafluoroethylene raw tape for thread sealing QB/T3628-1999 Standard download decompression password: www.bzxz.net

Professional Standard of the People's Republic of China
Polytetrafluoroethylene raw tape for thread sealing
Subject content and scope of application
ZB G33 005-89
This standard specifies the acceptance requirements and methods for unsintered tape (i.e. raw tape) made of polytetrafluoroethylene dispersed resin by pressing and calendering without any additives.
This standard is applicable to polytetrafluoroethylene raw tape used in threaded joint sealing and contact with strong oxidants and chemical flammable and explosive sealing.
2 Reference standards
GB1040
GB2918
GB6672
Plastic tensile test method
Standard environment for conditioning and testing plastic specimens Determination of thickness of plastic films and sheets Mechanical measurement method GB6673
Determination of length and width of plastic films and sheets 3 Product classification
3.1 Brand
3.2 Specifications
See Table 1.
Unstretched tape
Stretched tape (not specified in this standard)
Note: Other specifications can be negotiated and produced.
4 Technical requirements
4.1 Appearance
0.10±0.03
5+0.5 No more than 1 broken head
10+0.5 No more than 2 broken heads, 15+0.5 No more than 3 broken heads3±0.5;26±0.5,52±0.5
White, uniform texture, smooth surface, no cracks, damage or peeling. 4.2 Performance indicators
See Table 2.
Approved by the Ministry of Light Industry of the People's Republic of China on February 24, 1989 and implemented on July 1, 1989
Apparent density
Tensile strength
Elongation
Volatilization loss
5 Test method
5.1 Appearance
ZB G33 005--89
Observe with the naked eye at a vertical distance of 30 cm under natural light. 5.2 Dimensions
5.2.1 Instruments and measuring tools
The thickness gauge used shall comply with the provisions of GB6672, and the steel tape measure and steel plate ruler shall comply with the provisions of GB6673. 5.2.2 Measurement method
5.2.2.1 The thickness shall be measured in accordance with the method specified in Article 3.5 of GB6672. 5.2.2.2 The length shall be measured in accordance with the method specified in Chapter 2 of GB6673. 5.2.2.3 The width shall be determined in accordance with the method specified in Chapter 4 of GB6673. 5.3 State adjustment
According to the normal deviation range specified in Chapter 3 of GB2918, the sample shall be adjusted for more than 1 hour. 5.4 Apparent density
5.4.1 Sampling method
Spread the raw tape on a flat table and cut a 1m long test piece at right angles along the length of the sample. 5.4.2 Instruments and measuring tools
Use the same instruments and measuring tools as those in 5.2.1 and a balance with a sensitivity of 0.01g. 5.4.3 Measurement method
Measure the length, width and thickness of the test piece according to the measurement method in 5.2.2, and then weigh it on a balance to an accuracy of 0.1g. 5.4.4 Calculation method
The apparent density is calculated according to formula (1):
Wherein: P,-
apparent density, g/cm2;
test piece mass, g;
L—test piece length, cm;
b——test piece width, cm;
d—test piece thickness, cm.
5.5 Tensile strength and elongation
5.5.1 Dimensions of test pieces
(1)
When the width of the raw tape is less than 25 mm, the N-type test piece in GB1040 shall be used. When the width is greater than or equal to 25 mm, the test piece shown in Figure 1 shall be used. Each group of test pieces shall not be less than 5. 340
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5.5.2 Testing instrument
ZB G33 005-89
120±1
5.5.2.1 The tensile testing machine shall comply with the provisions of Chapter 10 of GB1040. 5.5.2.2 The moving speed of the testing machine fixture is (200±20) mm/min. 5.5.3 Testing method
It shall be carried out in accordance with Chapters 12 to 15 of GB1040. 5.5.4 Calculation method
5.5.4.1 The tensile strength shall be calculated according to formula (2): F
Where: T-
Tensile strength, MPa;
Maximum load, N;wwW.bzxz.Net
Specimen width, mm;
Specimen thickness, mm.
5.5.4.2 Calculation of elongation
Elongation is calculated according to formula (3):
Where: E—elongation,%;
× 100
L, effective distance between markings when the sample begins to break after being stretched, mm; L, original distance between markings of the sample, mm.
Note: The elongation is recorded at the beginning of the break of the sample. 5.6 Determination of volatile loss
5.6.1 Volatilization loss refers to the percentage of mass lost by the sample under specified conditions. 5.6.2 Measuring tools and equipment
Unit: mm
(2)
25mL or 30mL porcelain crucible, electric blast drying oven, muffle furnace, sintering furnace, analytical balance with a sensitivity of 0.1mg, dryer and material clamps.
5.6.3 Test steps
5.6.3.1 Treatment of porcelain crucible
Wash a 25mL or 30mL porcelain crucible and place it in a muffle furnace at (500±5)℃ and burn it for 1h (for new porcelain crucibles, soak it in 6N hydrochloric acid first, wash it and then place it in the muffle furnace). Take out the crucible and cool it in the air for 1~3min, move it into a desiccator, and cool it for 45min. The crucible treatment is considered complete. Place it in a desiccator for long-term storage. When doing this test again, just put the porcelain crucible into an electric heating blast drying oven at a temperature of (150±5)℃ for 2h and use it. If it is not properly stored, re-treat it according to the above method. 5.6.3.2 Weighing samples
Weigh three samples with a mass of about 1.0g. 5.6.3.3 Drying treatment of samples
ZBG33005—89
Put the weighed samples into porcelain crucibles and transfer them into an electric blast drying oven at a temperature of (150±5)°C. After 2 hours, take them out and place them in a desiccator to cool to room temperature. Take out the samples and weigh them accurately to 0.1mg to obtain a mass m1. 5.6.3.4 Sintering treatment of samples
Put the weighed samples after drying treatment into crucibles and load them into a sintering furnace together and maintain the furnace temperature at (370±5)°C. After 2 hours, naturally cool down to about 150°C and transfer them into a desiccator to cool to room temperature. Take out the samples and weigh them accurately to 0.1mg to obtain a mass m2. 5.6.4 Calculation of volatile loss
The volatile loss is calculated according to formula (4):
W= m2 ×100
Where: W——volatilization loss, %;
The mass of the test piece after drying at 150℃ for 2h, g; m
m2——The mass of the test piece after sintering at 370℃ for 2h, g. 6 Inspection rules
6.1 Raw tapes of the same brand, process and specification are batches. 6.2 Factory inspection items shall include appearance specifications and shall be inspected by 5% sampling. 6.3 Type inspection
(4)
Should include the test items specified in Chapter 4. Except for the volatilization loss which is tested once every quarter, the other items shall be measured once per batch. When the measured results do not meet the performance indicators, double samples shall be taken for retesting. If they are still unqualified, they shall be treated as unqualified. 7
Marking, packaging, transportation, storage
7.1 Marking
The product marking shall include the manufacturer's name, product name, product specifications, manufacturing date or production batch number. 7.2 Packaging
Packaging: Single roll packaging. Since the raw tape is prone to static electricity and easy to absorb dust and dirt, it is stipulated that for each single roll without pollution, damage, deformation and other defects, it is packaged in a small plastic bag, and then packaged in a large plastic bag and carton. 7.3 Transportation
Prevent heavy pressure, sun exposure and rain during transportation. 7.4 Storage
The raw tape should be stored in a clean warehouse in a packaged state, away from fire sources. Additional remarks:
This standard is under the jurisdiction of the Plastics Research Institute of the Ministry of Light Industry. This standard was jointly drafted by Tianjin Plastics Factory No. 9, Chenguang Chemical Research Institute No. 3, Beijing Plastics Research Institute and other units. This standard adopts Japanese Industrial Standard JISK-6885-1979 "Polytetrafluoroethylene unsintered tape for thread sealing".
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