HG/T 2903-1997 Fine-grained polytetrafluoroethylene resin for molding
Some standard content:
HG/T2903---1997
This standard adopts ASTMD1457:1992 "Standard Specification for Polytetrafluoroethylene Molding and Extrusion Materials" in a non-equivalent manner. The polytetrafluoroethylene resin specified in this standard is similar to the V-type resin in ASTM D 1457 of the United States, and the technical contents of the two are not exactly the same. The main technical differences between this standard and ASTMD1457 are: the particle size in this standard is less than 15% on the 65μm sieve, while the average particle size in ASTMD1457 is less than 100μm; the melting point temperature in this standard is 327℃±5℃C, while it is 327℃±10℃ in ASTMD1457; the test rate of the tensile test in this standard is 100mm/min, while it is 50mm/min in ASTMD1457. This standard adds two indicators, cleanliness and bulk density. The previous version of this standard is GB8329-87 "Polytetrafluoroethylene resin fine particle molding powder". The differences from the previous version are: the name of the standard is changed from "Polytetrafluoroethylene Resin Fine Particle Molding Powder" to "Polytetrafluoroethylene Resin Fine Particle Molding"; the "Scope" and "Citation Standards" chapters are added; the number of sampling units is changed from 50% to GB6678; the inspection categories are standardized in the inspection rules, and the quality objection handling method is added. From the date of implementation of this standard, the original national standard GB8329-87 "Polytetrafluoroethylene Resin Fine Particle Molding Powder" is abolished. This standard is 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 (TC15/SC4). The responsible drafting unit of this standard: Jinan Chemical Plant. The main drafters of this standard: Li Guanglie and Chen Hongchang. 929
1 Scope
Chemical Industry Standard of the People's Republic of China
Finely granular polytetrafluoroethylene resin used for molding
HG/T2903-1997
Replaces GB8329-87
This standard specifies the model, requirements, test methods, inspection rules, marking, packaging, storage and transportation of fine granular polytetrafluoroethylene resin used for molding.
This standard is applicable to white powdery polytetrafluoroethylene resin produced by suspension polymerization and crushed. 2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB1033—86Test method for density and relative density of plastics GB/T1040—92Test method for tensile properties of plastics (neqISO/R527:1966) GB1408—89Test method for power frequency electrical strength of solid insulating materials GB 2918—82(89) Prohibited
Standard environment for conditioning and testing of plastic specimens (eqvISO291:1977) General rules for sampling of chemical products
GB 6678—86
Nomenclature of polytetrafluoroethylene materials
HG/T 2899—1997
HG/T 2900—1997
HG/T 2901—1997
3 Model
Test method for bulk density of polytetrafluoroethylene resin Test method for particle size of polytetrafluoroethylene resin
According to HG/T According to GB/T 2899, the model of fine-particle polytetrafluoroethylene resin for molding is PTFE SM021, which is subdivided into electrical materials and fillers according to their uses, and their models are PTFE SM021 (E) and PTFE SM021 (F) respectively. 4 Requirements
The technical requirements of fine-particle polytetrafluoroethylene resin for molding shall comply with the provisions of Table 1. 5 Test methods
5.1 Sampling
Sampling shall be carried out in accordance with GB6678. The number of sampling units shall be in accordance with the provisions in Table 2 of GB6678--86, and the sampling unit shall be calculated in packaging barrels. Take the required samples in equal amounts from a certain number of packaging barrels, with a total amount of 1kg for full performance testing, mix them evenly, and put them in a clean and dry container. The samples should be kept clean and dry to prevent dust, water vapor and other impurities from mixing in. It is allowed to draw uniform and representative samples on the production line or packaging line. Indicate the manufacturer name, product name, model, batch number and sampling date on the sampling container. Approved by the Ministry of Chemical Industry of the People's Republic of China on May 23, 1997. 930
Implemented on October 1, 1997
Cleanliness
Tensile strength, MPa
Elongation at break.%
Bulk density, g/L
Particle size (retention number on 65um sieve).%
Water content, %
Melting point,
Standard relative density
Thermal instability index
Electrical strength.MV/m
5.2 Sample preparation
5.2.1 Picture sample
HG/T 2903—-1997
Table 1 Technical requirements
PTFE SM021(E)
First-class product
Qualified product
The board surface is white and the texture is uniform. No impurities are allowed
PTFE SM021(F)
·Qualified products
The plate surface has uniform texture, and the total number of impurities and spots does not exceed six, among which the impurities of 0.5mm~2mm do not exceed = pieces, and the spots of 2mm~3mm do not exceed one
300~450
327±5
2.13~2.19
Weigh 14.5g of resin and add it evenly into the clean mold cavity. After scraping and closing the mold, put it into the hydraulic press and slowly pressurize it. Maintain the pressure at 34.5MPa for 2min~5min, release the pressure, take out the preform with a diameter of 76mm from the mold cavity, smooth the burrs, wipe it clean, place the preform on a flat metal plate after numbering, and send it into a sintering furnace with forced hot air circulation and rotating working disk. Heat it freely to the starting temperature and sinter it according to the conditions of method A in Table 2.
5.2.2 Samples of standard relative density and thermal instability index Weigh 12.0g ± 0.1g of resin and pour it into the cavity of a round simple mold with an inner diameter of 28.6mm and a height of at least 76mm. Then put it in a hydraulic press and gradually pressurize it to a pressure of 34.5MPa. Keep the pressure for 2min, release the pressure, take out the preform from the cavity, smooth the burrs, wipe it clean, number it, and send it to a sintering furnace with forced hot air circulation and a rotating working disk, and heat it freely to the starting temperature. The standard relative density sample is sintered according to the conditions of method A in Table 2, and the generalized relative density sample in the thermal instability index is sintered according to the conditions of method C in Table 2. 5.2.3 Film Sample
Weigh 350g ± 50g of resin and add them evenly into the mold cavity with an outer diameter of 57mm and an inner diameter of 18mm under double-sided pressure. Scrape it flat, close the mold, put it into the hydraulic press and slowly pressurize it. The initial pressure is 3.45MPa, and the pressure is maintained for 1min~2min. Then, the pressure is steadily increased to 34.5MPa within 3min~5min. After maintaining the pressure for 2min~5min, the pressure is released, and the preform is taken out from the vertical direction of the mold cavity, the burrs are smoothed, and it is sent into a sintering furnace with forced hot air circulation and a rotating T-operating disk. The temperature is freely increased to the starting temperature and sintered according to the conditions of method B in Table 2. After sintering, the burrs are placed at room temperature for more than 24h, and then turned into a film with a thickness of 0.045mm±0.005mm. The sintering conditions of each sample are shown in Table 2.
5.3 Cleanliness test
Take 4 samples prepared according to 5.2.1 and visually test the cleanliness of the samples under 20W~40W fluorescent lamp. The distance between the sample and the lamp is 10cm~15cm, and the grade is determined by the test result of the worst sample. 5.4 Determination of tensile strength and elongation at break 5.4.1 Sample
Starting temperature,
Heating rate, C/h
Housing temperature,
Housing time, min
Cooling rate, ℃/h
Second holding temperature, ℃
Second-holding time, min
Cooling time to room temperature,h
HG/T 2903 --- 1997
Table 2 Sintering conditions of specimens
76 Disc and standard relative density specimen
120±10
380±6
294±6
$57 Rod and film rough
60±10
371±6
240±15
238±6bZxz.net
General relative density specimen
120±10
380±6
360±15
294±6
Disc punched tensile specimen prepared in 5.2.1. The specimen dimensions are shown in Figure 1. The thickness deviation of the same specimen shall not exceed 0.1mm, and each group of specimens shall not be less than 5.
5.4.2 Specimen Conditioning
Figure 1 Dimensions of tensile specimens
According to GB2918, condition at 23℃±2℃ for at least 2h. 5.4.3 Operation steps
11.5±0.3
Measured by the method specified in GB/T1040, where the test temperature is 23℃±2℃ and the test rate is 100mm/min±10mm/min.
5.4.4 Result Expression
a) Tensile strength is calculated according to GB/T1040. b) Elongation at break is calculated according to formula (1):
Where: E, ——Elongation at break, %,
Ln Initial length of specimen, mm,
—Length of specimen at break, mm.
+..+.++o++++
(1)
c) The test results are expressed as the arithmetic mean of each group of samples. If the measured value of a sample is lower than the specified standard, the data shall be processed as follows: the deviation between the measured value of each sample and the average value shall not exceed 10%. If it exceeds ±10%, it shall be discarded. After discarding, the remaining samples shall not be less than 3.
5.5 Determination of bulk density
The determination shall be carried out according to the method specified in HG/T2900. 932
5.6 Determination of particle size
HG/T 2903-1997
The determination shall be carried out according to the method specified in Appendix A of HG/T2901--1997. 5.7 Determination of moisture content
5.7.1 Apparatus
a) Electric constant temperature vacuum drying oven, vacuum degree less than 95.8 kPa; a) Vacuum pump, ultimate pressure less than 1.3 Pa; c) Lead weighing blood, 10 mL syringe box;
d) Analytical balance, sensitivity 0.1 mg.
5.7.2 Operation steps
Weigh 35g~~40g of resin (accurate to 0.0001g) in a constant weight aluminum weighing blood III with a lid. Then put the aluminum weighing blood into the vacuum drying oven and dry it for 1.5h at an absolute pressure of 13.3 kPa and a temperature of 150℃±1℃. Take out the weighing dish from the drying oven, cover it, put it in a desiccator to cool for at least 30 minutes, and then weigh it again, and calculate the mass loss of the resin during the drying process. 5.7.3 Result expression
The moisture content is calculated according to formula (2).
mi-m3×100
Wherein: X---water content, %;
Mass of resin, weighing blood and cap before drying, g; mass of weighing blood and cap, g;
m3-mass of resin, weighing blood and cap after drying, g. The arithmetic mean of two parallel samples is taken as the test result, and the difference between the two is not greater than 0.003%. 5.8 Determination of melting point
5.8.1 Apparatus
Differential scanning calorimeter (DSC).
5.8.2 Procedure
(2)
Weigh about 8 mg of resin and seal it in an aluminum crucible. Use a blank aluminum crucible as a reference. Under the protection of nitrogen at a flow rate of 20 mL/min, heat it to 380°C at a heating rate of 10°C/min. Then, cool it to 240°C at a rate of 10°C/min. Then, heat it to complete melting of polytetrafluoroethylene at a heating rate of 10°C/min. The peak temperature of the second melting peak is the melting point of polytetrafluoroethylene resin. 5.9 Determination of standard relative density
Prepare two specimens according to 5.2.2 and measure them according to the provisions of Method A in GB1033-86. The results are taken as the average. 5.10 Determination of thermal instability index
The thermal instability index is a measure of the decrease in relative molecular mass of a resin after being heated for a certain period of time. 5.10.1 Determination of general relative density
Prepare two specimens according to 5.2.2 and measure them according to Method A in GB1033-86. Take the average value of the results. 5.10.2 Expression of results
The thermal instability index is calculated according to formula (3): T11=(ESG-SSG)X1 000°
Wherein: T11
The thermal instability index;
ESG general relative density,
-standard relative density.
5.11 Determination of electrical strength
(3)
This method is to apply a DC voltage to the specimen in a continuous and uniformly stepped-up manner until it breaks down, measure the breakdown voltage value, and calculate the electrical strength of the specimen.
5.11.1 Sample
HG/T 2903—1997
A film with a thickness of 0.045mm±0.005mm and a length of 1m prepared according to 5.2.3. 5.11.2 Apparatus
a) Automatic high-voltage breakdown device, with a current waveform distortion rate of less than 5%; b) The electrode is the electrode (a) in Figure 1 of GB1408-89; c) The thickness gauge has an accuracy of 0.001mm.
5.11.3 Test conditions
According to the normal temperature and humidity conditions in GB2918.
5.11.4 Sample state adjustment
Adjust according to the normal temperature and humidity specified in GB2918. 5.11.5 Operation steps
Put the two-layer film sample between the two electrodes, increase the voltage uniformly at a speed of 1kV/s until breakdown, and record the instantaneous breakdown voltage value. Take 10 points at random for the same measurement, measure the thickness near each breakdown point of the sample, measure each point 3 times and take the average value. The thickness measurement accuracy is not greater than ±0.001mm.
5.11.6 Explanation of results
Perform in accordance with GB1408. The test results are expressed as the arithmetic mean of 10 points and are integers. 6 Inspection rules
6.1 The inspection is carried out in batches, and each batch of resin produced is a batch. 6.2 Each batch of products must be inspected by the quality inspection department of the manufacturer, and the manufacturer shall ensure that all products leaving the factory meet the requirements of this standard. Each batch of products shall be accompanied by a quality inspection report. 6.3 Inspection is divided into factory inspection and type inspection. The items (1) cleanliness, (2) tensile strength, (3) elongation at break, and (10) electrical strength specified in Table 1 of this standard are mandatory inspection items for each batch, and the rest are random inspection items. Among them, (4) bulk density, (5) particle size, (6) moisture content, (8) standard relative density, and (9) thermal instability index are randomly inspected once every 50 batches; (7) melting point is randomly inspected once a year. Type inspection shall be carried out in accordance with the provisions of Article 6.6.1 of GB/T1.3-87.
6.4 If the user unit needs to inspect the received products, it shall be carried out in accordance with the provisions of this standard. Acceptance inspection shall be carried out within one month of receiving the products.
6.5 If any of the inspection results does not meet the requirements specified in this standard, samples of the same number of sampling units shall be taken from the batch of products again, and the unqualified items shall be re-inspected, and the grade shall be determined based on the re-inspection results. 6.6 When the supply and demand parties have objections to the product quality, they can resolve the dispute through negotiation or ask the statutory quality inspection department to arbitrate. 7 Marking, packaging, storage and transportation
7.1 Marking
The packaging barrel of this product should have firm and clear markings, indicating the manufacturer, product name, product model, net content, batch number or production date and this standard number.
7.2 Packaging
This product should be sealed in a double-layer plastic bag inner packaging, and the outer packaging should be a hard barrel. The net content of each barrel is 25kg. Each packaging barrel should be accompanied by a product certificate issued by the quality inspection department. 7.3 Storage and transportation
This product is transported as non-dangerous goods. It should be protected from moisture and severe vibration during transportation. This product should be stored in a clean, cool and dry place to prevent rain, sunlight, moisture, dust and other impurities. 9342 Conditioning of the specimen
Figure 1 Dimensions of tensile specimen
According to GB2918, condition at 23℃±2℃ for at least 2h. 5.4.3 Operating steps
11.5±0.3
Measured by the method specified in GB/T1040, where the test temperature is 23℃±2℃ and the test rate is 100mm/min±10mm/min.
5.4.4 Result expression
a) Tensile strength is calculated according to GB/T1040. b) Elongation at break is calculated according to formula (1):
Where: E, ——Elongation at break, %,
Ln Initial length of specimen, mm,
—Length of specimen at break, mm.
+..+.++o++++
(1)
c) The test results are expressed as the arithmetic mean of each group of samples. If the measured value of a sample is lower than the specified standard, the data shall be processed as follows: the deviation between the measured value of each sample and the average value shall not exceed 10%. If it exceeds ±10%, it shall be discarded. After discarding, the remaining samples shall not be less than 3.
5.5 Determination of bulk density
Determine according to the method specified in HG/T2900. 932
5.6 Determination of particle size
HG/T 2903-1997
Determine according to the method specified in Appendix A of HG/T2901--1997. 5.7 Determination of moisture content
5.7.1 Apparatus
a) Electric constant temperature vacuum drying oven, vacuum degree less than 95.8 kPa; a) Vacuum pump, ultimate pressure less than 1.3 Pa; c) Lead weighing blood, 10 mL syringe box;
d) Analytical balance, sensitivity 0.1 mg.
5.7.2 Operation steps
Weigh 35g~~40g of resin (accurate to 0.0001g) in a constant weight aluminum weighing blood with a lid. Then put the aluminum weighing blood into the vacuum drying oven and dry it for 1.5h at an absolute pressure of 13.3 kPa and a temperature of 150℃±1℃. Take out the weighing dish from the drying oven, cover it, put it into a desiccator to cool for at least 30 minutes, and then weigh it again, and calculate the mass loss of the resin during the drying process. 5.7.3 Result expression
The moisture content is calculated according to formula (2).
mi-m3×100
Wherein: X---water content, %;
Mass of resin, weighing blood and cap before drying, g; mass of weighing blood and cap, g;
m3-mass of resin, weighing blood and cap after drying, g. The arithmetic mean of two parallel samples is taken as the test result, and the difference between the two is not greater than 0.003%. 5.8 Determination of melting point
5.8.1 Apparatus
Differential scanning calorimeter (DSC).
5.8.2 Procedure
(2)
Weigh about 8 mg of resin and seal it in an aluminum crucible. Use a blank aluminum crucible as a reference. Under the protection of nitrogen at a flow rate of 20 mL/min, heat it to 380°C at a heating rate of 10°C/min. Then, cool it to 240°C at a rate of 10°C/min. Then, heat it to complete melting of polytetrafluoroethylene at a heating rate of 10°C/min. The peak temperature of the second melting peak is the melting point of polytetrafluoroethylene resin. 5.9 Determination of standard relative density
Prepare two specimens according to 5.2.2 and measure them according to the provisions of Method A in GB1033-86. The results are taken as the average. 5.10 Determination of thermal instability index
The thermal instability index is a measure of the decrease in relative molecular mass of a resin after being heated for a certain period of time. 5.10.1 Determination of general relative density
Prepare two specimens according to 5.2.2 and measure them according to Method A in GB1033-86. The results are averaged. 5.10.2 Expression of results
The thermal instability index is calculated according to formula (3): T11 = (ESG-SSG) X1 000 °
Wherein: T11
The thermal instability index;
ESG general relative density,
-standard relative density.
5.11 Determination of electrical strength
(3)
This method is to apply a DC voltage to the specimen in a continuous and uniformly stepped-up manner until it breaks down, measure the breakdown voltage value, and calculate the electrical strength of the specimen.
5.11.1 Sample
HG/T 2903—1997
A film with a thickness of 0.045mm±0.005mm and a length of 1m prepared according to 5.2.3. 5.11.2 Apparatus
a) Automatic high-voltage breakdown device, with a current waveform distortion rate of less than 5%; b) The electrode is the electrode (a) in Figure 1 of GB1408-89; c) The thickness gauge has an accuracy of 0.001mm.
5.11.3 Test conditions
According to the normal temperature and humidity conditions in GB2918.
5.11.4 Sample state adjustment
Adjust according to the normal temperature and humidity specified in GB2918. 5.11.5 Operation steps
Put the two-layer film sample between the two electrodes, increase the voltage uniformly at a speed of 1kV/s until breakdown, and record the instantaneous breakdown voltage value. Take 10 points at random for the same measurement, measure the thickness near each breakdown point of the sample, measure each point 3 times and take the average value. The thickness measurement accuracy is not greater than ±0.001mm.
5.11.6 Explanation of results
Perform in accordance with GB1408. The test results are expressed as the arithmetic mean of 10 points and are integers. 6 Inspection rules
6.1 The inspection is carried out in batches, and each batch of resin produced is a batch. 6.2 Each batch of products must be inspected by the quality inspection department of the manufacturer, and the manufacturer shall ensure that all products leaving the factory meet the requirements of this standard. Each batch of products shall be accompanied by a quality inspection report. 6.3 Inspection is divided into factory inspection and type inspection. The items (1) cleanliness, (2) tensile strength, (3) elongation at break, and (10) electrical strength specified in Table 1 of this standard are mandatory inspection items for each batch, and the rest are random inspection items. Among them, (4) bulk density, (5) particle size, (6) moisture content, (8) standard relative density, and (9) thermal instability index are randomly inspected once every 50 batches; (7) melting point is randomly inspected once a year. Type inspection shall be carried out in accordance with the provisions of Article 6.6.1 of GB/T1.3-87.
6.4 If the user unit needs to inspect the received products, it shall be carried out in accordance with the provisions of this standard. Acceptance inspection shall be carried out within one month of receiving the products.
6.5 If any of the inspection results does not meet the requirements specified in this standard, samples of the same number of sampling units shall be taken from the batch of products again, and the unqualified items shall be re-inspected, and the grade shall be determined based on the re-inspection results. 6.6 When the supply and demand parties have objections to the product quality, they can resolve the dispute through negotiation or ask the statutory quality inspection department to arbitrate. 7 Marking, packaging, storage and transportation
7.1 Marking
The packaging barrel of this product should have firm and clear markings, indicating the manufacturer, product name, product model, net content, batch number or production date and this standard number.
7.2 Packaging
This product should be sealed in a double-layer plastic bag inner packaging, and the outer packaging should be a hard barrel. The net content of each barrel is 25kg. Each packaging barrel should be accompanied by a product certificate issued by the quality inspection department. 7.3 Storage and transportation
This product is transported as non-dangerous goods. It should be protected from moisture and severe vibration during transportation. This product should be stored in a clean, cool and dry place to prevent rain, sunlight, moisture, dust and other impurities. 9342 Conditioning of the specimen
Figure 1 Dimensions of tensile specimen
According to GB2918, condition at 23℃±2℃ for at least 2h. 5.4.3 Operating steps
11.5±0.3
Measured by the method specified in GB/T1040, where the test temperature is 23℃±2℃ and the test rate is 100mm/min±10mm/min.
5.4.4 Result expression
a) Tensile strength is calculated according to GB/T1040. b) Elongation at break is calculated according to formula (1):
Where: E, ——Elongation at break, %,
Ln Initial length of specimen, mm,
—Length of specimen at break, mm.
+..+.++o++++
(1)
c) The test results are expressed as the arithmetic mean of each group of samples. If the measured value of a sample is lower than the specified standard, the data shall be processed as follows: the deviation between the measured value of each sample and the average value shall not exceed 10%. If it exceeds ±10%, it shall be discarded. After discarding, the remaining samples shall not be less than 3.
5.5 Determination of bulk density
The determination shall be carried out according to the method specified in HG/T2900. 932
5.6 Determination of particle size
HG/T 2903-1997
The determination shall be carried out according to the method specified in Appendix A of HG/T2901--1997. 5.7 Determination of moisture content
5.7.1 Apparatus
a) Electric constant temperature vacuum drying oven, vacuum degree less than 95.8 kPa; a) Vacuum pump, ultimate pressure less than 1.3 Pa; c) Lead weighing blood, 10 mL syringe box;
d) Analytical balance, sensitivity 0.1 mg.
5.7.2 Operation steps
Weigh 35g~~40g of resin (accurate to 0.0001g) in a constant weight aluminum weighing blood III with a lid. Then put the aluminum weighing blood into the vacuum drying oven and dry it for 1.5h at an absolute pressure of 13.3 kPa and a temperature of 150℃±1℃. Take out the weighing dish from the drying oven, cover it, put it in a desiccator to cool for at least 30 minutes, and then weigh it again, and calculate the mass loss of the resin during the drying process. 5.7.3 Result expression
The moisture content is calculated according to formula (2).
mi-m3×100
Wherein: X---water content, %;
Mass of resin, weighing blood and cap before drying, g; mass of weighing blood and cap, g;
m3-mass of resin, weighing blood and cap after drying, g. The arithmetic mean of two parallel samples is taken as the test result, and the difference between the two is not greater than 0.003%. 5.8 Determination of melting point
5.8.1 Apparatus
Differential scanning calorimeter (DSC).
5.8.2 Procedure
(2)
Weigh about 8 mg of resin and seal it in an aluminum crucible. Use a blank aluminum crucible as a reference. Under the protection of nitrogen at a flow rate of 20 mL/min, heat it to 380°C at a heating rate of 10°C/min. Then, cool it to 240°C at a rate of 10°C/min. Then, heat it to complete melting of polytetrafluoroethylene at a heating rate of 10°C/min. The peak temperature of the second melting peak is the melting point of polytetrafluoroethylene resin. 5.9 Determination of standard relative density
Prepare two specimens according to 5.2.2 and measure them according to the provisions of Method A in GB1033-86. The results are taken as the average. 5.10 Determination of thermal instability index
The thermal instability index is a measure of the decrease in relative molecular mass of a resin after being heated for a certain period of time. 5.10.1 Determination of general relative density
Prepare two specimens according to 5.2.2 and measure them according to Method A in GB1033-86. Take the average value of the results. 5.10.2 Expression of results
The thermal instability index is calculated according to formula (3): T11=(ESG-SSG)X1 000°
Wherein: T11
The thermal instability index;
ESG general relative density,
-standard relative density.
5.11 Determination of electrical strength
(3)
This method is to apply a DC voltage to the specimen in a continuous and uniformly stepped-up manner until it breaks down, measure the breakdown voltage value, and calculate the electrical strength of the specimen.
5.11.1 Sample
HG/T 2903—1997
A film with a thickness of 0.045mm±0.005mm and a length of 1m prepared according to 5.2.3. 5.11.2 Apparatus
a) Automatic high-voltage breakdown device, with a current waveform distortion rate of less than 5%; b) The electrode is the electrode (a) in Figure 1 of GB1408-89; c) The thickness gauge has an accuracy of 0.001mm.
5.11.3 Test conditions
According to the normal temperature and humidity conditions in GB2918.
5.11.4 Sample state adjustment
Adjust according to the normal temperature and humidity specified in GB2918. 5.11.5 Operation steps
Put the two-layer film sample between the two electrodes, increase the voltage uniformly at a speed of 1kV/s until breakdown, and record the instantaneous breakdown voltage value. Take 10 points at random for the same measurement, measure the thickness near each breakdown point of the sample, measure each point 3 times and take the average value. The thickness measurement accuracy is not greater than ±0.001mm.
5.11.6 Explanation of results
Perform in accordance with GB1408. The test results are expressed as the arithmetic mean of 10 points and are integers. 6 Inspection rules
6.1 The inspection is carried out in batches, and each batch of resin produced is a batch. 6.2 Each batch of products must be inspected by the quality inspection department of the manufacturer, and the manufacturer shall ensure that all products leaving the factory meet the requirements of this standard. Each batch of products shall be accompanied by a quality inspection report. 6.3 Inspection is divided into factory inspection and type inspection. The items (1) cleanliness, (2) tensile strength, (3) elongation at break, and (10) electrical strength specified in Table 1 of this standard are mandatory inspection items for each batch, and the rest are random inspection items. Among them, (4) bulk density, (5) particle size, (6) moisture content, (8) standard relative density, and (9) thermal instability index are randomly inspected once every 50 batches; (7) melting point is randomly inspected once a year. Type inspection shall be carried out in accordance with the provisions of Article 6.6.1 of GB/T1.3-87.
6.4 If the user unit needs to inspect the received products, it shall be carried out in accordance with the provisions of this standard. Acceptance inspection shall be carried out within one month of receiving the products.
6.5 If any of the inspection results does not meet the requirements specified in this standard, samples of the same number of sampling units shall be taken from the batch of products again, and the unqualified items shall be re-inspected, and the grade shall be determined based on the re-inspection results. 6.6 When the supply and demand parties have objections to the product quality, they can resolve the dispute through negotiation or ask the statutory quality inspection department to arbitrate. 7 Marking, packaging, storage and transportation
7.1 Marking
The packaging barrel of this product should have firm and clear markings, indicating the manufacturer, product name, product model, net content, batch number or production date and this standard number.
7.2 Packaging
This product should be sealed in a double-layer plastic bag inner packaging, and the outer packaging should be a hard barrel. The net content of each barrel is 25kg. Each packaging barrel should be accompanied by a product certificate issued by the quality inspection department. 7.3 Storage and transportation
This product is transported as non-dangerous goods. It should be protected from moisture and severe vibration during transportation. This product should be stored in a clean, cool and dry place to prevent rain, sunlight, moisture, dust and other impurities. 9346 Determination of particle size
HG/T 2903-1997
The determination shall be carried out according to the method specified in Appendix A of HG/T2901--1997. 5.7 Determination of moisture content
5.7.1 Apparatus
a) Electric constant temperature vacuum drying oven, vacuum degree less than 95.8 kPa a) Vacuum pump, ultimate pressure less than 1.3 Pa; c) Lead weighing blood, 10 mL syringe box;
d) Analytical balance, sensitivity 0.1 mg.
5.7.2 Operation steps
Weigh 35g~~40g of resin (accurate to 0.0001g) in a constant weight aluminum weighing blood with a lid. Then put the aluminum weighing blood into a vacuum drying oven and dry it for 1.5 hours at an absolute pressure of 13.3 kPa and a temperature of 150℃±1℃. Take out the weighing dish from the drying oven, cover it, put it in the dryer to cool for at least 30 minutes, then weigh it again and calculate the mass loss of the resin during the drying process. 5.7.3 Result expression
The moisture content is calculated according to formula (2).
mi-m3×100
Wherein: X---moisture content, %;
The mass of the resin, weighing blood and cover before drying, g; the mass of weighing blood and cover, g;
m3-the mass of the resin, weighing blood and cover after drying, g. The arithmetic mean of the two parallel samples is taken as the test result, and the difference between the two is not greater than 0.003%. 5.8 Determination of melting point
5.8.1 Apparatus
Differential scanning calorimeter (DSC).
5.8.2 Procedure
(2)
Weigh about 8 mg of resin and seal it in an aluminum crucible. Use a blank aluminum crucible as a reference. Under the protection of nitrogen at a flow rate of 20 mL/min, heat it to 380°C at a heating rate of 10°C/min. Then, cool it to 240°C at a rate of 10°C/min. Then, heat it to complete melting of polytetrafluoroethylene at a heating rate of 10°C/min. The peak temperature of the second melting peak is the melting point of polytetrafluoroethylene resin. 5.9 Determination of standard relative density
Prepare two specimens according to 5.2.2 and measure them according to the provisions of Method A in GB1033-86. The results are taken as the average. 5.10 Determination of thermal instability index
The thermal instability index is a measure of the decrease in relative molecular mass of a resin after being heated for a certain period of time. 5.10.1 Determination of general relative density
Prepare two specimens according to 5.2.2 and measure them according to Method A in GB1033-86. Take the average value of the results. 5.10.2 Expression of results
The thermal instability index is calculated according to formula (3): T11=(ESG-SSG)X1 000°
Wherein: T11
The thermal instability index;
ESG general relative density,
-standard relative density.
5.11 Determination of electrical strength
(3)
This method is to apply a DC voltage to the specimen in a continuous and uniformly stepped-up manner until it breaks down, measure the breakdown voltage value, and calculate the electrical strength of the specimen.
5.11.1 Sample
HG/T 2903—1997
A film with a thickness of 0.045mm±0.005mm and a length of 1m prepared according to 5.2.3. 5.11.2 Apparatus
a) Automatic high-voltage breakdown device, with a current waveform distortion rate of less than 5%; b) The electrode is the electrode (a) in Figure 1 of GB1408-89; c) The thickness gauge has an accuracy of 0.001mm.
5.11.3 Test conditions
According to the normal temperature and humidity conditions in GB2918.
5.11.4 Sample state adjustment
Adjust according to the normal temperature and humidity specified in GB2918. 5.11.5 Operation steps
Put the two-layer film sample between the two electrodes, increase the voltage uniformly at a speed of 1kV/s until breakdown, and record the instantaneous breakdown voltage value. Take 10 points at random for the same measurement, measure the thickness near each breakdown point of the sample, measure each point 3 times and take the average value. The thickness measurement accuracy is not greater than ±0.001mm.
5.11.6 Explanation of results
Perform in accordance with GB1408. The test results are expressed as the arithmetic mean of 10 points and are integers. 6 Inspection rules
6.1 The inspection is carried out in batches, and each batch of resin produced is a batch. 6.2 Each batch of products must be inspected by the quality inspection department of the manufacturer, and the manufacturer shall ensure that all products leaving the factory meet the requirements of this standard. Each batch of products shall be accompanied by a quality inspection report. 6.3 Inspection is divided into factory inspection and type inspection. The items (1) cleanliness, (2) tensile strength, (3) elongation at break, and (10) electrical strength specified in Table 1 of this standard are mandatory inspection items for each batch, and the rest are random inspection items. Among them, (4) bulk density, (5) particle size, (6) moisture content, (8) standard relative density, and (9) thermal instability index are randomly inspected once every 50 batches; (7) melting point is randomly inspected once a year. Type inspection shall be carried out in accordance with the provisions of Article 6.6.1 of GB/T1.3-87.
6.4 If the user unit needs to inspect the received products, it shall be carried out in accordance with the provisions of this standard. Acceptance inspection shall be carried out within one month of receiving the products.
6.5 If any of the inspection results does not meet the requirements specified in this standard, samples of the same number of sampling units shall be taken from the batch of products again, and the unqualified items shall be re-inspected, and the grade shall be determined based on the re-inspection results. 6.6 When the supply and demand parties have objections to the product quality, they can resolve the dispute through negotiation or ask the statutory quality inspection department to arbitrate. 7 Marking, packaging, storage and transportation
7.1 Marking
The packaging barrel of this product should have firm and clear markings, indicating the manufacturer, product name, product model, net content, batch number or production date and this standard number.
7.2 Packaging
This product should be sealed in a double-layer plastic bag inner packaging, and the outer packaging should be a hard barrel. The net content of each barrel is 25kg. Each packaging barrel should be accompanied by a product certificate issued by the quality inspection department. 7.3 Storage and transportation
This product is transported as non-dangerous goods. It should be protected from moisture and severe vibration during transportation. This product should be stored in a clean, cool and dry place to prevent rain, sunlight, moisture, dust and other impurities. 9346 Determination of particle size
HG/T 2903-1997
The determination shall be carried out according to the method specified in Appendix A of HG/T2901--1997. 5.7 Determination of moisture content
5.7.1 Apparatus
a) Electric constant temperature vacuum drying oven, vacuum degree less than 95.8 kPa a) Vacuum pump, ultimate pressure less than 1.3 Pa; c) Lead weighing blood, 10 mL syringe box;
d) Analytical balance, sensitivity 0.1 mg.
5.7.2 Operation steps
Weigh 35g~~40g of resin (accurate to 0.0001g) in a constant weight aluminum weighing blood with a lid. Then put the aluminum weighing blood into a vacuum drying oven and dry it for 1.5 hours at an absolute pressure of 13.3 kPa and a temperature of 150℃±1℃. Take out the weighing dish from the drying oven, cover it, put it in the dryer to cool for at least 30 minutes, then weigh it again and calculate the mass loss of the resin during the drying process. 5.7.3 Result expression
The moisture content is calculated according to formula (2).
mi-m3×100
Wherein: X---moisture content, %;
The mass of the resin, weighing blood and cover before drying, g; the mass of weighing blood and cover, g;
m3-the mass of the resin, weighing blood and cover after drying, g. The arithmetic mean of the two parallel samples is taken as the test result, and the difference between the two is not greater than 0.003%. 5.8 Determination of melting point
5.8.1 Apparatus
Differential scanning calorimeter (DSC).
5.8.2 Procedure
(2)
Weigh about 8 mg of resin and seal it in an aluminum crucible. Use a blank aluminum crucible as a reference. Under the protection of nitrogen at a flow rate of 20 mL/min, heat it to 380°C at a heating rate of 10°C/min. Then, cool it to 240°C at a rate of 10°C/min. Then, heat it to complete melting of polytetrafluoroethylene at a heating rate of 10°C/min. The peak temperature of the second melting peak is the melting point of polytetrafluoroethylene resin. 5.9 Determination of standard relative density
Prepare two specimens according to 5.2.2 and measure them according to the provisions of Method A in GB1033-86. The results are taken as the average. 5.10 Determination of thermal instability index
The thermal instability index is a measure of the decrease in relative molecular mass of a resin after being heated for a certain period of time. 5.10.1 Determination of general relative density
Prepare two specimens according to 5.2.2 and measure them according to Method A in GB1033-86. The results are averaged. 5.10.2 Expression of results
The thermal instability index is calculated according to formula (3): T11 = (ESG-SSG) X1 000 °
Wherein: T11
The thermal instability index;
ESG general relative density,
-standard relative density.
5.11 Determination of electrical strength
(3)
This method is to apply a DC voltage to the specimen in a continuous and uniformly stepped-up manner until it breaks down, measure the breakdown voltage value, and calculate the electrical strength of the specimen.
5.11.1 Sample
HG/T 2903—1997
A film with a thickness of 0.045mm±0.005mm and a length of 1m prepared according to 5.2.3. 5.11.2 Apparatus
a) Automatic high-voltage breakdown device, with a current waveform distortion rate of less than 5%; b) The electrode is the electrode (a) in Figure 1 of GB1408-89; c) The thickness gauge has an accuracy of 0.001mm.
5.11.3 Test conditions
According to the normal temperature and humidity conditions in GB2918.
5.11.4 Sample state adjustment
Adjust according to the normal temperature and humidity specified in GB2918. 5.11.5 Operation steps
Put the two-layer film sample between the two electrodes, increase the voltage uniformly at a speed of 1kV/s until breakdown, and record the instantaneous breakdown voltage value. Take 10 points at random for the same measurement, measure the thickness near each breakdown point of the sample, measure each point 3 times and take the average value. The thickness measurement accuracy is not greater than ±0.001mm.
5.11.6 Explanation of results
Perform in accordance with GB1408. The test results are expressed as the arithmetic mean of 10 points and are integers. 6 Inspection rules
6.1 The inspection is carried out in batches, and each batch of resin produced is a batch. 6.2 Each batch of products must be inspected by the quality inspection department of the manufacturer, and the manufacturer shall ensure that all products leaving the factory meet the requirements of this standard. Each batch of products shall be accompanied by a quality inspection report. 6.3 Inspection is divided into factory inspection and type inspection. The items (1) cleanliness, (2) tensile strength, (3) elongation at break, and (10) electrical strength specified in Table 1 of this standard are mandatory inspection items for each batch, and the rest are random inspection items. Among them, (4) bulk density, (5) particle size, (6) moisture content, (8) standard relative density, and (9) thermal instability index are randomly inspected once every 50 batches; (7) melting point is randomly inspected once a year. Type inspection shall be carried out in accordance with the provisions of Article 6.6.1 of GB/T1.3-87.
6.4 If the user unit needs to inspect the received products, it shall be carried out in accordance with the provisions of this standard. Acceptance inspection shall be carried out within one month of receiving the products.
6.5 If any of the inspection results does not meet the requirements specified in this standard, samples of the same number of sampling units shall be taken from the batch of products again, and the unqualified items shall be re-inspected, and the grade shall be determined based on the re-inspection results. 6.6 When the supply and demand parties have objections to the product quality, they can resolve the dispute through negotiation or ask the statutory quality inspection department to arbitrate. 7 Marking, packaging, storage and transportation
7.1 Marking
The packaging barrel of this product should have firm and clear markings, indicating the manufacturer, product name, product model, net content, batch number or production date and this standard number.
7.2 Packaging
This product should be sealed in a double-layer plastic bag inner packaging, and the outer packaging should be a hard barrel. The net content of each barrel is 25kg. Each packaging barrel should be accompanied by a product certificate issued by the quality inspection department. 7.3 Storage and transportation
This product is transported as non-dangerous goods. It should be protected from moisture and severe vibration during transportation. This product should be stored in a clean, cool and dry place to prevent rain, sunlight, moisture, dust and other impurities. 9342 Result expression
The thermal instability index is calculated according to formula (3): T11=(ESG-SSG)X1 000 °
Wherein: T11
The thermal instability index;
ESG generalized relative density,
-standard relative density.
5.11 Determination of electrical strength
(3)
This method is to apply a DC voltage to the sample in a continuous and uniform voltage-boosting manner until it breaks down, measure the breakdown voltage value, and calculate the electrical strength of the sample.
5.11.1 Sample
HG/T 2903—1997
A film with a thickness of 0.045 mm ± 0.005 mm and a length of 1 m prepared according to 5.2.3. 5.11.2 Apparatus
a) Automatic high-voltage breakdown device, current waveform distortion rate is less than 5%; b) The electrode is the electrode (a) in Figure 1 of GB1408-89; c) The thickness gauge accuracy is 0.001mm.
5.11.3 Test conditions
According to the normal temperature and humidity conditions in GB2918.
5.11.4 Sample state adjustment
Adjust according to the normal temperature and humidity specified in GB2918. 5.11.5 Operation steps
Put the two-layer film sample between the two electrodes, increase the voltage uniformly at a speed of 1kV/s until breakdown, and record the instantaneous breakdown voltage value. Take any 10 points for the same measurement, measure the thickness near each breakdown point of the sample, measure each point 3 times and take the average value. The thickness measurement accuracy is not greater than ±0.001mm.
5.11.6 Explanation of results
Perform in accordance with GB1408. The test results are expressed as the arithmetic mean of 10 points and are rounded to an integer. 6 Inspection rules
6.1 The inspection is carried out in batches, with each batch of resin produced as a batch. 6.2 Each batch of products must be inspected by the quality inspection department of the manufacturer, and the manufacturer must ensure that all products leaving the factory meet the requirements of this standard. Each batch of products should be accompanied by a quality inspection report. 6.3 Inspection is divided into factory inspection and type inspection. The items (1) cleanliness, (2) tensile strength, (3) elongation at break, and (10) electrical strength specified in Table 1 of this standard are mandatory inspection items for each batch, and the rest are random inspection items. Among them, (4) bulk density, (5) particle size, (6) moisture content, (8) standard relative density, and (9) thermal instability index are inspected once every 50 batches; (7) melting point is inspected once a year. Type inspection shall be carried out in accordance with the provisions of Article 6.6.1 of GB/T1.3-87.
6.4 If the user unit needs to inspect the received products, it shall be carried out in accordance with the provisions of this standard. Acceptance inspection shall be carried out within one month of receiving the products.
6.5 If any of the inspection results do not meet the requirements of this standard, samples of double sampling units shall be taken from the batch of products, and the unqualified items shall be re-inspected, and the grade shall be determined based on the re-inspection results. 6.6 When the supply and demand parties have objections to the product quality, they can negotiate to resolve the dispute or ask the statutory quality inspection department to arbitrate. 7 Marking, packaging, storage and transportation
7.1 Marking
The packaging barrel of this product should have a firm and clear mark indicating the manufacturer, product name, product model, net content, batch number or production date and this standard number.
7.2 Packaging
This product should be sealed in a double-layer plastic bag, and the outer packaging should be a hard barrel. The net content of each barrel is 25kg. Each packaging barrel should be accompanied by a product certificate from the quality inspection department. 7.3 Storage and transportation
This product is transported as non-dangerous goods. It should be protected from moisture and severe vibration during transportation. This product should be stored in a clean, cool and dry place, and protected from rain, sunlight, moisture, dust and other impurities. 9342 Result expression
The thermal instability index is calculated according to formula (3): T11=(ESG-SSG)X1 000 °
Wherein: T11
The thermal instability index;
ESG generalized relative density,
-standard relative density.
5.11 Determination of electrical strength
(3)
This method is to apply a DC voltage to the sample in a continuous and uniformly stepped-up manner until it breaks down, measure the breakdown voltage value, and calculate the electrical strength of the sample.
5.11.1 Sample
HG/T 2903—1997
A film with a thickness of 0.045 mm ± 0.005 mm and a length of 1 m prepared according to 5.2.3. 5.11.2 Apparatus
a) Automatic high-voltage breakdown device, current waveform distortion rate is less than 5%; b) The electrode is the electrode (a) in Figure 1 of GB1408-89; c) The thickness gauge accuracy is 0.001mm.
5.11.3 Test conditions
According to the normal temperature and humidity conditions in GB2918.
5.11.4 Sample state adjustment
Adjust according to the normal temperature and humidity specified in GB2918. 5.11.5 Operation steps
Put the two-layer film sample between the two electrodes, increase the voltage uniformly at a speed of 1kV/s until breakdown, and record the instantaneous breakdown voltage value. Take any 10 points for the same measurement, measure the thickness near each breakdown point of the sample, measure each point 3 times and take the average value. The thickness measurement accuracy is not greater than ±0.001mm.
5.11.6 Explanation of results
Perform in accordance with GB1408. The test results are expressed as the arithmetic mean of 10 points and are rounded to an integer. 6 Inspection rules
6.1 The inspection is carried out in batches, with each batch of resin produced as a batch. 6.2 Each batch of products must be inspected by the quality inspection department of the manufacturer, and the manufacturer must ensure that all products leaving the factory meet the requirements of this standard. Each batch of products must be accompanied by a quality inspection report. 6.3 Inspection is divided into factory inspection and type inspection. The items (1) cleanliness, (2) tensile strength, (3) elongation at break, and (10) electrical strength specified in Table 1 of this standard are mandatory inspection items for each batch, and the rest are random inspection items. Among them, (4) bulk density, (5) particle size, (6) moisture content, (8) standard relative density, and (9) thermal instability index are inspected once every 50 batches; (7) melting point is inspected once a year. Type inspection shall be carried out in accordance with the provisions of Article 6.6.1 of GB/T1.3-87.
6.4 If the user unit needs to inspect the received products, it shall be carried out in accordance with the provisions of this standard. Acceptance inspection shall be carried out within one month of receiving the products.
6.5 If any of the inspection results do not meet the requirements of this standard, samples of double sampling units shall be taken from the batch of products, and the unqualified items shall be re-inspected, and the grade shall be determined based on the re-inspection results. 6.6 When the supply and demand parties have objections to the product quality, they can negotiate to resolve the dispute or ask the statutory quality inspection department to arbitrate. 7 Marking, packaging, storage and transportation
7.1 Marking
The packaging barrel of this product should have a firm and clear mark indicating the manufacturer, product name, product model, net content, batch number or production date and this standard number.
7.2 Packaging
This product should be sealed in a double-layer plastic bag, and the outer packaging should be a hard barrel. The net content of each barrel is 25kg. Each barrel should be accompanied by a product certificate from the quality inspection department. 7.3 Storage and Transportation
This product is transported as a non-dangerous product. It should be protected from moisture and severe vibration during transportation. This product should be stored in a clean, cool and dry place, and protected from rain, sunlight, moisture, dust and other impurities. 934
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