GB/T 8802-2001 Determination of Vicat softening temperature of thermoplastic pipes and fittings
Some standard content:
GB/T 8802---2001
2-1988 "Method for Determining Vicat Softening Temperature of Rigid Polyvinyl Chloride (PVC-U) Pipe Fittings". This standard is a revision of GB/T8802-
This standard is equivalent to the international standard ISO2507:1995 "Thermoplastic Pipes and Fittings-Vicat Softening Temperature". The main revisions to this standard are:
1. The scope of application of the standard has been expanded. The revised standard is applicable to all low-crystalline or non-crystallized polymerized thermoplastic materials. 2. The load on the specimen is changed from 49.05N to (50±1)N. 3. A heating box with air circulation device is introduced, and it is stipulated that if there is no suitable heat transfer medium, a heating box with air circulation can also be used for testing.
This standard will replace GB/T8802-1988 from the date of implementation. Appendix A of this standard is the appendix of the standard.
This standard is proposed by China National Light Industry Federation. This standard is under the jurisdiction of the National Technical Committee for Standardization of Plastic Products. The drafting unit of this standard is Hebei Baoshuo Pipe Co., Ltd. The main drafters of this standard are Wang Yajiang, Gao Changquan and Sun Zhiwei. 87
GB/T 8802—2001
ISO Foreword
The International Organization for Standardization (ISO) is a worldwide federation composed of national standardization bodies (ISO member bodies). The work of formulating international standards is usually completed by ISO's technical committees. If each member body is interested in a project established by a technical committee, it has the right to participate in the work of the committee. International organizations (official or unofficial) that maintain contact with ISO may also participate in the relevant work. In the field of electrotechnical standardization, ISO maintains a close cooperative relationship with the International Electrotechnical Commission (IEC). The draft international standard (DIS) adopted by the technical committee is submitted to the member bodies for voting. It must obtain the consent of at least 75% of the member bodies participating in the voting before it can be officially published as an international standard. International Standard ISO 2507 was developed by ISO/TC138/SC5 (Technical Committee for Plastic Pipes, Fittings and Valves for Fluid Transportation - General Characteristics of Plastic Pipes, Fittings and Valves and Their Accessories - Test Methods and Basic Specifications). ISO 2507-1 and ISO 2507-2 replace the second edition of ISO 2507, ISO 2507: 1982 (due to technical revisions). Under the general title "Thermoplastic pipes and fittings - Vicat softening temperature", ISO 2507 contains the following parts: Part 1 General test methods Part 2: Test conditions for rigid polyvinyl chloride (PVC-U or chlorinated polyvinyl chloride (PVC-C) pipes and fittings and high-impact polyvinyl chloride (PVC-HI) pipes; Part 3: Test conditions for acrylonitrile-butadiene-styrene (ABS) and acrylonitrile-styrene-acrylic acid (ASA) pipes and fittings. 1 Scope National Standard of the People's Republic of China Thermoplastics pipes and fittings - Determination of vicat softening temperature This standard specifies the method for the determination of the Vicat softening temperature of thermoplastic pipes and fittings. GB/T 8802—2001 eqvIS0 2507:1995
Replaces GB/T8802---1988
This standard applies to thermoplastic materials whose temperature can be measured when the material begins to soften rapidly, and does not apply to crystalline or semi-crystalline polymeric materials.
2 Cited 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. GB/T2918-1998 Standard environment for conditioning and testing of plastic specimens (idtISO291:1997) GB/T8806--1988 Method for measuring dimensions of plastic pipes (eqvS03126:1974) 3 Principle
Place the sample in a liquid medium or a heating box and measure the temperature under constant temperature increase conditions. The standard indenter is pressed into the pipe under the action of a force of (50±1)N. The temperature when the specimen is cut from a material or pipe 1mm inside. The temperature when pressed into 1mm is the Vicat softening temperature (VST) of the specimen, unit: C. 4 Test apparatus
The test apparatus in this standard is shown in Figure 1. 4.1 Specimen support, load rod
The specimen support is used to place the specimen and can be easily immersed in the insulation bath. The support and the load rod for applying the load should be made of materials with a small thermal expansion coefficient (if the linear expansion coefficient of the load rod and the support part are different, their different deformation in length will cause reading deviation). Each instrument is calibrated with a rigid material with a low thermal expansion coefficient. The calibration should include the entire operating temperature range, and the calibration value for each temperature should be determined. If the calibration value is greater than or equal to 0.02mm, it should be marked and this calibration value should be considered in each subsequent test.
The load rod can move freely vertically. The support base is used to place the specimen, and the pressure needle is fixed at the end of the load rod (see Figure 1). 4.2 The material of the pressure needle
is preferably hard steel. The pressure needle is 3mm long and has a cross-sectional area of (1±0.015) mm2. It is installed at the bottom of the load rod. The end of the pressure needle should be flat and at right angles to the axis of the load rod. The pressure needle is not allowed to have defects such as burrs. 4.3 The micrometer (or other measuring instrument)
is used to measure the depth of the pressure needle pressing into the sample, and the accuracy should be less than or equal to 0.01mm. The pressure acting on the surface of the sample should be known (see the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, approved on October 24, 2001 and implemented on May 1, 2002
4.4 Load plate
GB/T 8802--2001
Installed on the load rod. The mass load should be at the center of the load plate so that the total pressure acting on the sample is controlled at (50 + 1) N. Since the downward pressure is a combined effect of the load rod, the pressure needle and the load plate, the elastic force of the dial gauge should not exceed 1 N. 1
1-dial gauge; 2-code; 3-load plate; 4-load rod; 5-liquid level: 6-pressure needle: 7-sample; 8-sample support Figure】Principle diagram of Vicat softening temperature determination
4.5 Magnetic code
The static load G-W+R+T=50N borne by the sample, the mass of the magnetic code to be added is calculated by formula (1): W=50-R||tt| |W is the mass of the magnetic code, N,
R is the mass of the pressure needle, load rod and load plate, N; T…the additional pressure of the micrometer or other measuring instrument, N. 4.6 Heating bath
Put a suitable liquid in the bath (see Notes 1 and 2) and immerse the test device in the liquid, with the specimen at least 35 mm below the surface of the medium. The bath should be equipped with an agitator and a heating device so that the liquid can be heated at a constant rate of (50 ± 5) °C per hour. During the test, the temperature change within each 6-minute interval should be within the range of (5 ± 0.5) °C. Note
Liquid paraffin, transformer oil, glycerin and silicone oil can be used as heat transfer media, and other media can also be used. But no matter which medium is selected For any material, it should be ensured that it is stable at the test temperature and that it does not affect the specimen during the test, such as softening, expansion or rupture. If there is no suitable heat transfer medium, a heating box with air circulation (4.8) can also be used. 2 The test results are related to the thermal conductivity of the heat transfer medium. Constant heating can be achieved by manual or automatic heating control, and the latter is recommended. Given the heating rate to be achieved starting from the initial test temperature, increase or decrease the heating power by adjusting a resistor or an adjustable transformer. In order to reduce the cooling time between two consecutive tests, it is recommended to install a cooling coil in the heating bath. Since the presence of coolant will affect its heating rate , therefore, the cooling coil should be removed or emptied before the next test. 4.7 Mercury thermometer
Local immersion mercury thermometer (or other suitable temperature measuring device), the graduation value is 0.5C. For the immersion depth of the mercury thermometer, see 7.3. 90
4.8 Heating box
GB/T8802—2001
The heating box must have an air circulation device and the temperature should be controlled within the range specified in the standard. 5 Test specimen
5.1 Sampling
5.1.1 Pipe
The test specimen should be an arc-shaped pipe section cut from the pipe along the axial direction, with the following dimensions: length about 50mm, width: 10mm~20mm. 5.1.2 Pipe fittings
The sample should be an arc segment cut from the socket, spigot or cylindrical surface of the pipe fitting. Its length is: for pipe fittings with a diameter less than or equal to 90mm, the sample length is equal to the socket length; for pipe fittings with a diameter greater than 90mm, the sample length is 50mm. The width is 10 mm to 20 mm.
The sample should be cut from a location without a parting line or injection point. 5.2 Sample preparation
5.2.1 If the wall thickness of the pipe or pipe fitting is greater than 6mm, the outer surface of the pipe or pipe fitting shall be processed by appropriate methods to reduce the wall thickness to 4mm. If the socket of the pipe fitting is threaded, the threaded part shall be machined off to make its surface smooth. 5.2.2 Samples with a wall thickness ranging from 2.4mm to 6mm (including 6mm) can be tested directly. 5.2.3 If the wall thickness of the pipe or pipe fitting is less than 2.4mm, two arc segments can be superimposed together to make the total thickness not less than 2.4mm. The lower pipe section sample used as the cushion layer should be flattened first. To this end, the sample can be heated to 140°C and kept for 15 minutes, and then placed between two smooth flat plates to flatten. The upper arc section should remain unchanged. 5.3 Number of samples
Two samples are used for each test, but when cutting the samples, several more samples should be provided to prepare for supplementary tests when the test results are too different.
6 Pretreatment
6.1 Pretreat the sample at a temperature 50°C below the expected Vicat softening temperature (VST) for at least 5 minutes. 6.2 For acrylonitrile-butadiene-styrene (ABS) and acrylonitrile-styrene-acrylic (ASA) samples, they should be dried in an oven at (90±2)°C for 2 hours, and then cooled at (23±2)°C and (50±5)% relative humidity for (15±1) minutes. Then treat according to 6.1.
7 Test Procedure
7.1 Adjust the temperature of the heating bath to about 50°C below the softening temperature of the specimen and maintain a constant temperature. 7.2 Place the specimen with the concave surface facing upward and horizontally under the indenter of the unloaded metal rod. The contact surface between the specimen and the base of the instrument should be flat. For specimens with a wall thickness of less than 2.4 mm, the end of the indenter should be placed on the concave surface of the unflattened specimen, and the flattened specimen should be placed below. The end of the indenter should be no less than 3 mm away from the edge of the specimen. 7.3 Place the test apparatus in the heating bath. The mercury ball of the thermometer or the sensor of the temperature measuring device should be at the same level as the specimen and as close to the specimen as possible.
7.4 After the indenter has been positioned for 5 minutes, add the required mass to the load plate so that the total axial pressure on the specimen is (50 ± 1) N. Record the reading of the tachometer (or other measuring instrument) or adjust it to zero. 7.5 Increase the temperature of the bath at a constant rate of (50 ± 5) °C per hour. The agitator should be turned on during the entire test. 7.6 When the pressure needle is pressed into the sample (1 ± 0.01) mm, quickly record the temperature at this time, which is the Vicat softening temperature (VST) of the sample.
Result expression
GB/T8802--2001
The arithmetic mean of the Vicat softening temperatures of the two samples is the Vicat softening temperature (VST) of the tested pipe or fitting, and the unit is (. If the difference between the results of the two samples is greater than 2C, no less than two samples should be taken for retesting. Test report
The test report should include the following contents:
a) This standard number;bzxz.net
b) Sample name, specification c) the preparation method, size and pretreatment conditions of the specimens, and whether the specimens are stacked; d) the heat transfer medium used in the heating tank; e) the starting temperature, heating rate, and applied load; f) the Vicat softening temperature of each specimen and the arithmetic mean of the Vicat softening temperatures of the two specimens, in C; g) any special changes in the appearance of the specimens during or after the test; h) any operating details that may affect the results and are not included in this standard; i) the tester and date.
GB/T8802--2001
Appendix A
(Appendix to the standard)
Basic provisions for Vicat softening temperature of different thermoplastic materials A1 Basic provisions for rigid polyvinyl chloride (PVC-U) pipes and fittings When tested in accordance with this standard, the Vicat softening temperature should be: PVC-U pipes not less than 79°C;
PVC-U injection molded fittings not less than 74°C;
For rigid polyvinyl chloride (PVC-U) pipes or fittings with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it should be explained in the relevant product standards. A2 Basic provisions for chlorinated polyvinyl chloride (PVC-C) pipes and fittings When tested in accordance with this standard, the Vicat softening temperature shall be: PVC-C non-pressure pipes shall not be less than 90'C:
PVC-C pressure pipes shall not be less than 110C;
PVC-C fittings shall not be less than 103C.
For chlorinated polyvinyl chloride (PVC-C) pipes or fittings with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it shall be stated in the relevant product standards. A3 Basic provisions for high-impact polyvinyl chloride (PVC-HI) pipes When tested in accordance with this standard, the Vicat softening temperature of high-impact polyvinyl chloride (PVC-HI) pipes shall not be less than 76C. For high-impact polyvinyl chloride (PVC-HI) pipes with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it shall be stated in the relevant product standards. A4 Basic provisions for acrylonitrile-butadiene-styrene (ABS) pipes and fittings When tested in accordance with this standard, the Vicat softening temperature of acrylonitrile-butadiene-styrene (ABS) pipes and fittings shall not be less than 90°C. For acrylonitrile-butadiene-styrene (ABS) pipes and fittings with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it shall be stated in the relevant product standards. A5 Basic provisions for propylene-styrene-acrylic acid (ASA) pipes and fittings When tested in accordance with this standard, the Vicat softening temperature of acrylonitrile-styrene-acrylic acid (ASA) pipes and fittings shall not be less than 90°C. For acrylonitrile-styrene-acrylic acid (ASA) pipes and fittings with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it shall be stated in the relevant product standards. Note: This appendix is only used as a reference for standard formulation and revision work. The Vicat softening temperature shall be determined based on the provisions of the corresponding product standards. 934 After the pressure needle is positioned for 5 minutes, add the required mass to the load plate so that the total axial pressure on the sample is (50 ± 1) N. Record the reading of the 1000 ppm (or other measuring instrument) or adjust it to zero. 7.5 Increase the temperature of the bath at a constant rate of (50 ± 5) °C per hour. The agitator should be turned on during the entire test. 7.6 When the pressure needle is pressed into the sample by (1 ± 0.01) mm, quickly record the temperature at this time. This temperature is the Vicat softening temperature (VST) of the sample.
Results
GB/T8802--2001
The arithmetic mean of the Vicat softening temperatures of the two samples is the Vicat softening temperature (VST) of the tested pipe or fitting, expressed in (. If the difference between the results of the two samples is greater than 2C, no less than two samples should be taken for retesting. Test report
The test report should include the following:
a) This standard number;
b) Sample name, specification c) the preparation method, size and pretreatment conditions of the specimens, and whether the specimens are stacked; d) the heat transfer medium used in the heating tank; e) the starting temperature, heating rate, and applied load; f) the Vicat softening temperature of each specimen and the arithmetic mean of the Vicat softening temperatures of the two specimens, in C; g) any special changes in the appearance of the specimens during or after the test; h) any operating details that may affect the results and are not included in this standard; i) the tester and date.
GB/T8802--2001
Appendix A
(Appendix to the standard)
Basic provisions for Vicat softening temperature of different thermoplastic materials A1 Basic provisions for rigid polyvinyl chloride (PVC-U) pipes and fittings When tested in accordance with this standard, the Vicat softening temperature should be: PVC-U pipes not less than 79°C;
PVC-U injection molded fittings not less than 74°C;
For rigid polyvinyl chloride (PVC-U) pipes or fittings with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it should be explained in the relevant product standards. A2 Basic provisions for chlorinated polyvinyl chloride (PVC-C) pipes and fittings When tested in accordance with this standard, the Vicat softening temperature shall be: PVC-C non-pressure pipes shall not be less than 90'C:
PVC-C pressure pipes shall not be less than 110C;
PVC-C fittings shall not be less than 103C.
For chlorinated polyvinyl chloride (PVC-C) pipes or fittings with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it shall be stated in the relevant product standards. A3 Basic provisions for high-impact polyvinyl chloride (PVC-HI) pipes When tested in accordance with this standard, the Vicat softening temperature of high-impact polyvinyl chloride (PVC-HI) pipes shall not be less than 76C. For high-impact polyvinyl chloride (PVC-HI) pipes with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it shall be stated in the relevant product standards. A4 Basic provisions for acrylonitrile-butadiene-styrene (ABS) pipes and fittings When tested in accordance with this standard, the Vicat softening temperature of acrylonitrile-butadiene-styrene (ABS) pipes and fittings shall not be less than 90°C. For acrylonitrile-butadiene-styrene (ABS) pipes and fittings with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it shall be stated in the relevant product standards. A5 Basic provisions for propylene-styrene-acrylic acid (ASA) pipes and fittings When tested in accordance with this standard, the Vicat softening temperature of acrylonitrile-styrene-acrylic acid (ASA) pipes and fittings shall not be less than 90°C. For acrylonitrile-styrene-acrylic acid (ASA) pipes and fittings with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it shall be stated in the relevant product standards. Note: This appendix is only used as a reference for standard formulation and revision work. The Vicat softening temperature shall be determined based on the provisions of the corresponding product standards. 934 After the pressure needle is positioned for 5 minutes, add the required mass to the load plate so that the total axial pressure on the sample is (50 ± 1) N. Record the reading of the 1000 ppm (or other measuring instrument) or adjust it to zero. 7.5 Increase the temperature of the bath at a constant rate of (50 ± 5) °C per hour. The agitator should be turned on during the entire test. 7.6 When the pressure needle is pressed into the sample by (1 ± 0.01) mm, quickly record the temperature at this time. This temperature is the Vicat softening temperature (VST) of the sample.
Results
GB/T8802--2001
The arithmetic mean of the Vicat softening temperatures of the two samples is the Vicat softening temperature (VST) of the tested pipe or fitting, expressed in (. If the difference between the results of the two samples is greater than 2C, no less than two samples should be taken for retesting. Test report
The test report should include the following:
a) This standard number;
b) Sample name, specification c) the preparation method, size and pretreatment conditions of the specimens, and whether the specimens are stacked; d) the heat transfer medium used in the heating tank; e) the starting temperature, heating rate, and applied load; f) the Vicat softening temperature of each specimen and the arithmetic mean of the Vicat softening temperatures of the two specimens, in C; g) any special changes in the appearance of the specimens during or after the test; h) any operating details that may affect the results and are not included in this standard; i) the tester and date.
GB/T8802--2001
Appendix A
(Appendix to the standard)
Basic provisions for Vicat softening temperature of different thermoplastic materials A1 Basic provisions for rigid polyvinyl chloride (PVC-U) pipes and fittings When tested in accordance with this standard, the Vicat softening temperature should be: PVC-U pipes not less than 79°C;
PVC-U injection molded fittings not less than 74°C;
For rigid polyvinyl chloride (PVC-U) pipes or fittings with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it should be explained in the relevant product standards. A2 Basic provisions for chlorinated polyvinyl chloride (PVC-C) pipes and fittings When tested in accordance with this standard, the Vicat softening temperature shall be: PVC-C non-pressure pipes shall not be less than 90'C:
PVC-C pressure pipes shall not be less than 110C;
PVC-C fittings shall not be less than 103C.
For chlorinated polyvinyl chloride (PVC-C) pipes or fittings with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it shall be stated in the relevant product standards. A3 Basic provisions for high-impact polyvinyl chloride (PVC-HI) pipes When tested in accordance with this standard, the Vicat softening temperature of high-impact polyvinyl chloride (PVC-HI) pipes shall not be less than 76C. For high-impact polyvinyl chloride (PVC-HI) pipes with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it shall be stated in the relevant product standards. A4 Basic provisions for acrylonitrile-butadiene-styrene (ABS) pipes and fittings When tested in accordance with this standard, the Vicat softening temperature of acrylonitrile-butadiene-styrene (ABS) pipes and fittings shall not be less than 90°C. For acrylonitrile-butadiene-styrene (ABS) pipes and fittings with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it shall be stated in the relevant product standards. A5 Basic provisions for propylene-styrene-acrylic acid (ASA) pipes and fittings When tested in accordance with this standard, the Vicat softening temperature of acrylonitrile-styrene-acrylic acid (ASA) pipes and fittings shall not be less than 90°C. For acrylonitrile-styrene-acrylic acid (ASA) pipes and fittings with stricter requirements for special purposes, when the specified minimum value is greater than the above given value, it shall be stated in the relevant product standards. Note: This appendix is only used as a reference for standard formulation and revision work. The Vicat softening temperature shall be determined based on the provisions of the corresponding product standards. 93
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