SJ 20779-2000 Test methods for thermosetting insulating plastic laminates
Some standard content:
Military Standard of Electronic Industry of the People's Republic of China FL5999
SJ20779--2000
Test methods for insulation plastics sheet laminated thermosetting2000-10~20Published
2000-10-20Implementation
Approved by the Ministry of Information Industry of the People's Republic of China 1 Scope
2 Referenced documents
3 Definition
4. General ticket request
5 Detailed requirements
Method 1010
Method 2010
Method 2020
Method 2030
Method 2040
Method 3010
Method 4010
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People's Republic of China Electronic Industry Military Standard Test methods for insulation plastics sheet laminated thermosetting 1 Scope
1.1 Subject content
SJ20779—2000
This standard specifies the test methods for thickness, bonding strength, bending strength, long-term heat resistance, tracking resistance and flame resistance of thermosetting insulation plastic laminates. 1.2 Scope of application
This standard applies to thermosetting insulation plastic laminates. 1.3 Method Numbers
This standard numbers each test method for easy reference. The method number consists of the word "method" followed by four Arabic numerals, and the order of the method is arranged according to the type of test method starting from the second digit.
The revision number of a test method is after the method number and is represented by a letter, such as "Method 3010A" for the first revision, "3010B" for the second revision, and so on. 2 References
GB/T1234—1995 High resistance electric heating alloy GB/T2036—94 Printed circuit terminology
GB2900.5—83 Electrical terminology Electrical insulating materials GB6553--86 Test method for evaluating the resistance to tracking and erosion of electrical insulating materials for use in severe environmental conditions
GJB360A—96 Test methods for electronic and electrical components SJ20747--1999 General specification for thermosetting insulating plastic laminates 3 Definitions
In addition to the relevant terms in GB/T2036 and GB2900.5, the following definitions are also added to the terms used in this standard. If the definitions in this standard conflict with the provisions in the above standards, this standard shall prevail. 3.1 Flatwise test A test in which the impact direction is perpendicular to the layer direction.
3.2 Edgewise test
Test in which the impact direction is parallel to the layer direction
The Ministry of Information Industry of the People's Republic of China issued on October 20, 2000 and implemented on October 20, 2000
3.3 Thermal life thermal life
SJ20779-2000
For a specific material or a simple combination of materials, the time required to decay to a specified end point at a specified temperature.
3.4 Thermal life curve thermal Hife curve The thermal life curve represents a performance of a certain material or a simple combination of materials at a specified temperature. The performance value is measured at room temperature and is a function of time.
3.5 Temperature index temperature index The temperature value corresponding to the heat resistance diagram at a specified time (usually 20000h) within a certain temperature range. This value represents the temperature index and cannot be expressed in temperature units. 3.6 Thermal endurance graph A linear relationship graph between the logarithm of thermal life and the reciprocal of the thermodynamic temperature value of aging (1/K). 3.7 Tracking contamination Tracking contamination The surface conductivity increases due to contamination, resulting in spark-induced tracking. 3.8 Ignition time ignition tine || tt || Under the conditions specified in the test method, the time required for ignition to continue. 3.9 Burning time burning time || tt || Under the conditions specified in the test method, the time the sample continues to burn after the ignition heat source is removed. 4 General requirements || tt || During the test, the requirements of the relevant specifications for the test shall be met. When the requirements of this standard are inconsistent with those of the general specification or relevant detailed specifications, the general specification or detailed specification shall prevail. 4.1 Test conditions
4.1.1 Standard atmospheric conditions for normal test
Unless otherwise specified in this standard or relevant specifications, the test shall be carried out under the following atmospheric conditions specified in GIB360A: Temperature: 15°℃~35°℃
Relative humidity: 20%~80%
Air pressure: 86kPa-106kPa
4.1.2 Standard atmospheric conditions for arbitration test
If the test parameters depend on temperature, humidity and air pressure, the test shall be carried out under the following standard atmospheric conditions for arbitration test:
Temperature: 23°℃±1°℃
Relative humidity: 48%~～52%
Air pressure: 86kPa～106kPa
4.1.3 Conditioning
Unless otherwise specified in the relevant specifications, the treatment shall be in accordance with the provisions of this standard. 4.1.4 Recovery conditions
Unless otherwise specified in this standard or relevant specifications, recovery shall be carried out in accordance with 4.1.4 of GJB360A. 4.2 Temperature changes in environmental test chambers (rooms) When an environmental test chamber is used, the test specimens shall be placed in the working area specified below. -2 -
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4.2.1 Changes in temperature over time in the working area SJ 20779--2000
The change of the reference point in the working area with time shall not exceed +2C4.2.2 The change of temperature in the working area with space At any given time, the deviation of the temperature of any point in the working area from the reference point temperature shall not exceed ±2"C.4.3 Sampling
Unless otherwise specified, the specimen shall be cut from an area greater than 25mn from the edge of the board.4.4 Number of specimens and test results
Unless otherwise specified in the relevant specifications, the number of specimens and test results shall be in accordance with the provisions of this standard.5 Detailed requirements
5.1 Method classification
The various test methods specified in this standard are divided into four categories, and the corresponding relationship between the method number and classification is as follows: Method 1001~1999 Dimensional inspection method
Mechanical and thermal properties test methodwww.bzxz.net
Method 2001~2999
Electrical properties test method
Method 3001 ~3999
Method 4001～4999
Environmental test method
1 Purpose
SJ20779--2000
Method 1010
This method is used to measure the thickness of insulating laminates to express the specifications of laminates. 2 Instrument
A thickness gauge or a ruler with a measuring error not exceeding 0.002mm, and a measuring head diameter of (6.00±0. 03)mum, the pressure acting on the sample is 10kPa~20kPa3 Sample
Laminate of any shape.
4 Test procedure
Use a thickness gauge or micrometer to measure 10 points evenly in an area greater than 6mm from the edge of the board. Be careful when measuring to avoid any impact, vibration and parallax.
5 Test results
The actual measured values at 10 points are the measurement results, accurate to 0.01mm. - 4 -
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SJ 20779-—2000
Method 2010
Adhesion strength
Adhesion strength is a measure of the adhesion between the layers of laminate material and is used for production control or acceptance testing. It can also be used to determine the degree of curing of laminates.
2 Specimens
2.1 The adhesion strength is related to the specimen thickness, so only specimens of the same thickness can be compared. 2.2 The standard specimen thickness is (12.70 ± 0.13) mm, the size is a 25 mm square, the two parallel sides should be smooth, and the side length deviation is 0.025 mm. Specimens thicker than 12.70 mm are machined symmetrically from both sides to 12.70 mm. 2.3 Test four specimens.
3 Apparatus
3.1 A universal material testing machine with an indication error not exceeding 1% of the minimum load. The indenter is equipped with a steel ball with a diameter of 10 mm.
4 Procedure
4.1 Fix the smooth side of the specimen to the workbench of the test equipment or a flat steel plate on the test bench with a clamp so that the steel ball is accurately aligned with the center of the specimen.
4.2 Use a test speed not exceeding 1.3 mm/min to load the specimen with the steel ball until the specimen layers crack. Record the maximum sustained load before failure. 4,3 The maximum force obtained is recorded as the bond strength. 5 Result
The minimum value of the four specimens is taken as the result. 6 Report
6.1 Material thickness
6.2 Specimen rupture load expressed in Newtons (N). 6.3 Report a single value.
1 Purpose
SJ 20779-2000
Method 2020
Impact Strength
This method uses notched specimens to determine the impact resistance of laminate materials by the vertical cantilever beam method. 2 Equipment
2.1 The cantilever beam impact tester is shown in Figure 1. The tester has a solid base with a specimen fixture mounted on it. A number of pendulums (or a base pendulum with external weight attached) are connected to it through a rigid frame and anti-friction bearings. There is also a pendulum clamping and releasing device, and a dial with a pointer, the indication error of which is not more than 1%. Impact point
Figure 1 Schematic diagram of cantilever beam impact tester
2.2 The tester should have a basic pendulum that transmits (2.710±0.135)" energy. This pendulum is suitable for all specimens that only need less than 85% of this energy. The pendulum may be independent and replaceable, or it may be attached to two faces of the impact center of a basic pendulum. For pendulums with the same calibrated weight, the additional weight shall not change the position of the impact center or the free hanging static point of the pendulum. Use pendulums with energies ranging from 2.710J to 21.680. For a series of pendulums, each pendulum shall be twice the next smaller energy. Each pendulum shall not exceed 0.5% of its standard energy. 2.3 The effective length of the pendulum is between 325mm and 406mm. When the pendulum is raised to an angle of 30° to 60° above the horizontal plane, the position of the pendulum clamping and release makes the vertical height of the impact end fall to (6102)mm, and the impact speed is about 3.46m/s-6-
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SJ20779—2000
2.4 The fixture, specimen and jaw assembly for the cantilever beam impact test are shown in Figure 2. The fixture holds the specimen firmly in place, with the long axis of the specimen vertical and at a true angle to the top face of the fixture, which bisects the notch angle, with an allowable deviation of ±0.12 mm. The radius of the upper edge of the jaws of the fixture is (0.25 ± 0.12) mm. For specimens with a thickness close to the lower limit of 3.2 mm, the lower half should be prevented from moving during clamping or testing. The impact end of the pendulum is a cylindrical surface with a radius of (0.79 + 0.12) mm, the axis is a horizontal plane and perpendicular to the plane of the pendulum's swing amplitude. The contact line of the impact end should be located at the impact center of the pendulum, not exceeding +2.54 mm. The rest of the adjacent pendulum's supporting impact edge should be recessed or tilted at a suitable angle so that only the cylindrical surface has a chance to contact the specimen during the specimen folding process. When the pendulum falls, it should be tangent to the specimen at (22 ± 0.05) mm above the jaws. Note: Testing machine out! A chart or other convenient correction method for wind resistance and energy loss due to falling shall be available. Specimen
R0.25±0.12
Fixed pin
RO.79±0.12
Movable clamp
C, D Parallelism of half faces within 0.025 mm Figure 2 Assembly of fixture, specimen and jaws
3 Specimen
3.1 Unless otherwise specified, five specimens shall be taken from the longitudinal and transverse directions of the plate. For plates with a thickness between 3.17 mm and 12.7 mm, the specimen width shall be the plate thickness: Plates with a thickness greater than 12.7 mm shall be mechanically tightened to 12.7 mm. The specimen dimensions are shown in Figure 3, and the cross section shall be a 12.7 mm square. To ensure the correct shape of the notch and the specified conditions, all specimens shall be notched according to Chapter 4.
$J 20779—2000
22. 5 ±0. 5*
410.16±0.05:
B 31.50~32.00:
C60.36~-63.50:DR0.25±0.05;
E12.70±0.15;
TSpecimen thickness
Figure 3 Specimen dimensions
3.2 The test is divided into forward impact and lateral impact. When conducting a forward test, the notch should be added on the processing surface of the single-sided machine-cut plate. If the specimen is cut from a thick plate, it should be noted whether the specimen is taken from the surface or center of the thick plate. 3.3 For plates between 3.17 mm and 12.7 mm, if several specimens are required to be stacked for testing, the specimens shall be stacked to a total width of 6.35 mm to 12.7 mm. Each piece shall be precisely aligned and connected by clamping, bolting or gluing, and machined to the appropriate size and then notched. Composite specimens shall only be tested in the lateral direction. The use of composite specimens shall be recorded in the test result report. Note: Special attention shall be paid to the selection of solvents or adhesives, which shall not affect the impact strength of the material. If solvents or solvent-containing adhesives are used, a conditioning process shall be specified to ensure that the solvent is completely evaporated before testing. 3.4 Each specimen shall be free of distortion, each pair of parallel surfaces shall be perpendicular to each other, and there shall be no scratches, pits or indentations. According to these requirements, visually inspect the straight edges, right angles and plate surfaces of the specimens and measure them with a vernier caliper. If visual inspection or picking test finds that one or more of the above requirements are not met, the specimen shall be discarded or mechanically increased to the appropriate size and shape before testing.
4 Processing of specimen notches
4.1 Use a milling machine or other suitable machine to increase the notch to an accuracy of 0.025mm. The feed rate and cutting speed should be kept constant throughout the opening process. Since single-tooth milling cutters are easy to grind out the required shape and the specimen is smoother after cutting, they are more commonly used. The tool should be carefully ground to ensure its sharpness and avoid adding roughness. A tool with no rake angle and a back angle of [5°~20° can obtain satisfactory processing conditions. 4.2 The specimen notch processing can be carried out individually or in groups. Unnotched spare materials or standard samples should be placed behind the processed specimens to Avoid deformation or breakage of the milling cutter when it exits the last specimen. 4.3 The profile of the cutter teeth should be consistent with the notch shape and depth of the test specimen in Figure 3. The angle of the notch is 45°1°, the radius of curvature of the point is (0.25±0.05) mm, and the notch angle bisector plane should be basically perpendicular to the specimen surface: the error shall not be less than 2°
4.4 During the notch processing, the thickness remaining in the specimen should be (10.16±0.05) mm. This dimension is checked by randomly measuring at least 20% of a group of specimens processed simultaneously. The micrometer used for measurement has a measuring head profile of 42°±2°, and the top The point radius of curvature is (0.13±0.07) mm. Each specimen must be tested during arbitration. 4.5 The selection of cutting speed and feed speed should be suitable for the material being tested. If the conditions are not selected properly, the quality of the notch will be adversely affected by the thermal deformation and thermal stress generated during the cutting process. Usually, a higher cutting speed and a low feed rate can avoid overheating during processing. Good milling conditions for different materials can be determined through experiments.
4.6 Usually, after a milling cutter adds 300 or more notches, the roughness, angle and top radius of the notch should be checked with a 60x magnifying glass. If it does not meet the requirements, a new tool should be replaced. 5 Conditioning
5.1 Unless otherwise specified, the specimen should be at 23°C before testing. ±2\C, relative humidity (50+5)% for not less than 40ha
5.2 The test is carried out under the same conditions as above. If there is any objection, the temperature tolerance is ±1°C and the relative humidity tolerance is ±2%.
6 Test steps
6.1 Check whether the specimen meets the requirements of Chapter 3 and Chapter 4. Measure the size of the notch of each specimen to an accuracy of 0.025mm and record the width and thickness of the specimen. 6.2 Test at least five pieces of each sample according to the treatment conditions of Chapter 5. The nominal width of each group of specimens is the same. 6.3 Clamp the specimen accurately and firmly in the specimen clamp (see 2.4) so that the energy consumption of the breaking specimen is within the range of 15%~85% of the scale, and record the specimen fracture impact energy and appearance. 6.4 Calculate the average impact strength of each group of specimens. The impact strength is expressed as the impact energy divided by the specimen width, and the unit is J/m. Only specimens with the same width and the same fracture type can be averaged. The values of unbroken specimens are not averaged.
7 Report
7.1 Complete identification mark of the material to be tested: including the source of the sample, manufacturer, etc. 7.2 Preparation of the sample, test conditions, sample handling time after notching, sample cutting direction and test direction. Number of test drops for each sample test.
7.3 Pendulum energy (J).
7.4 Average impact strength of each group of samples (J/m). 7.5 Standard width of the sample is marked in brackets after the average impact strength. -9-
1 Self-
SJ 20779--2000
Method 2030
Bending strength
This method is used to determine the bending strength of rigid insulating laminates when a specific load is applied to a sample of a specific size and shape. For quality control and identification.
2 Samples
2.1 Take 4 samples in the longitudinal and transverse directions of the plate, and the edges of the samples in the length direction should be processed smooth. 2.2 The size of the sample shall be as specified in Table 1 according to the thickness. For paper and cotton base laminates with a nominal thickness greater than 25 mm, the two surfaces of the specimen shall be symmetrically machined to a thickness of 25 mm. For glass fiber and nylon fiber base laminates with a nominal thickness greater than 13 mm, the two surfaces of the specimen shall be symmetrically machined to a thickness of 13 mm. 3 Equipment
3.1 Universal material testing machine
With appropriate scale, its crosshead can run at a constant speed as shown in Table 1. The error of the load in the measuring system shall not exceed ±1% of the maximum measured load. A set of error measurement devices shall be available. 3.2 Load head and support
The load head and support shall be cylindrical surfaces. To avoid excessive indentation or failure due to stress concentration under the load head, the radius of the load head and support shall be at least 3 mm for all specimens. For specimens of 3 mm and above thickness, the support radius may be up to 1.5 times the specimen thickness. If obvious indentation or pressure loss occurs, the arc of the load head in contact with the specimen shall be large enough to prevent the specimen from contacting the side wall of the load head. 4 Conditioning
4.1 Before testing, the specimens shall be conditioned for not less than 40 h at 23°C ± 2°C and relative humidity (50 ± 5)%. In case of dispute, the temperature deviation shall be ±1°C and the relative humidity deviation shall be ±2%. 4.2 Test Conditions
The test shall be conducted at 23°C ± 2°C and relative humidity (50 ± 5)%. In case of dispute, the temperature deviation shall be ±1°C and the relative humidity deviation shall be ±2%.
5 Procedure
5.1 Measure the specimen length to the nearest 1 mm and the width and thickness of the untested specimen at the middle of the support spacing to the nearest 0.01 mm. For specimens with a thickness of less than 2.5 mm, the measured value shall be accurate to 0.001 mm. 5.2 Measure the support spacing, the deviation shall be within ±1% of the specified spacing. 5.3 Adjust the testing machine at the vertical speed of the crosshead as required in Table 1. 5.4 Adjust the load head and the support so that the axes of the cylindrical surfaces are parallel to each other and the load head is located in the middle of the two supports. Parallelism can be checked with a flat plate with parallel grooves. The middle of the specimen is on the two supports and the long axis of the specimen is perpendicular to the load head and the support. 5.5 Apply the load at the crosshead speed specified in Table 1 until the specimen breaks. - 10 -
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