GB/T 15023-1994 Test methods for solvent-free polymerizable resin compounds for electrical insulation
Some standard content:
National Standard of the People's Republic of China
Test methods for solventless polymerisable resinous compounds used for electrical insulation
Test methods for solventless polymerisable resinous compounds used for electrical insulation GB/T15023—94
This standard refers to and adopts the International Electrotechnical Commission (IEC) Publication 455-2 (Edition: -1974) Specification for solventless polymerisable resinous compounds for electrical insulation Part 2: Test methods". 1 Subject content and applicable scope
This standard specifies the test methods for solventless polymerisable resinous compounds for electrical insulation other than coating powders. This standard applies to bath-free polymerisable resinous compounds for electrical insulation other than coating powders (hereinafter referred to as compounds). 2 Reference standards
GB528-82 Determination of tensile properties of vulcanized rubber Test method for density and relative density of plastics
GB 1033-86
Determination method for linear expansion coefficient of plastics
GB 1036-89
GB1037-87 Test method for water vapor permeability of plastic film and sheet (cup method) GB1043-79 (confirmed in 1989) Test method for impact of simply supported beam of plastics GB 1408--89
GB 140988
Test method for power frequency electrical strength of solid insulating materials Test method for relative dielectric band number and dielectric loss factor of solid insulating materials at power frequency, audio frequency and high frequency (including meter wavelength)
Test method for volume resistivity and surface resistivity of solid insulating materials GB 1410--89
GB1634-79 (confirmed in 1989) Test method for heat deformation temperature of plastic bending load (abbreviated as heat deformation temperature) Determination of ash content in paints
GR1747-79 (confirmed in 1985)
Determination of chemical resistance of paint films
GB1763-79 (confirmed in 1985)
GB1981-89 Test method for solvent-containing insulating varnishes GB2411-80 (confirmed in 1989) Test method for plastics' hardness GB2423.16-90 Basic environmental testing procedures for electrical and electronic products Test J: Long test method GB2895-82 (confirmed in 1989) Determination of acid value of unsaturated polyester resin GB339982 (confirmed in 1989) Test method for thermal conductivity of plastics Hot plate method 4 Determination method for comparative condensation tracking index and leakage tracking index of solid insulating materials under humid conditions GB 4207—84
GB 4612—84
GB 513085
GB 6031—85
GB 6553—86
GB 7139-
Determination of epoxy equivalent of epoxy compounds
Test methods for electrical insulating laminates
Determination of international hardness of vulcanized rubber (30～85IRHD) Routine test method Test method for evaluating the resistance to tracking and erosion of electrical insulating materials used under severe environmental conditions Determination of the content of gas in homopolymers and copolymers of vinyl chloride Approved by the State Administration of Technical Supervision on April 12, 1994, 12-01-01
GB 7193. 2--87
GB/T GB 15023-94 Determination of hydroxyl value of unsaturated ester resin GB7193.4-87 Determination of reactivity of unsaturated ester resin at 80℃ GB 9341-: 88 Test method for flexural properties of plastics GB 9342-88 Test method for Rockwell hardness of plastics Determination of hardness of low hardness vulcanized rubber (10~35IRHD) GB986688 Test method for electrolytic corrosion caused by insulating materials Test method for determining the burning properties of solid electrical insulating materials after exposure to an ignition source 9 Guidelines for determining the heat resistance of electrical insulating materials General description of the development of aging test methods and evaluation of test results GB 11026. 1--89
GB11207-89 Determination of hardness of high hardness (85100IRHD) vulcanized rubber JB3282-83 Test method for relative surface discharge breakdown resistance of solid insulating materials 3 Test description
3.1 Unless otherwise specified in the product standard, all tests should be carried out under environmental conditions of 23+2℃ and relative humidity of 50%±5%: 3.2 The test items should be clearly specified in the product standard, whether to test individual components or the prepared mixture, otherwise, it should be regarded as a test of the prepared mixture. When testing the prepared mixture, it should be noted that the use period of such mixture may be short. It should be kept at a suitable temperature and the test should be completed as soon as possible. 3.3 Test report
The test report should include the following contents:
4 Appearance
Name of the standard code:
Name, model, batch number, source of the tested material or name and model of the instrument and equipment used by the manufacturer; Test result value:
Differences from the provisions of this standard;
Abnormal phenomena or other contents that need to be explained; Name or code of the test personnel:
Test date.
Part 1 Test of composite materials in delivery status
4.1 Test tube method
Pour the composite materials into a clean, dry, colorless and transparent glass test tube with an inner diameter of about 15mm and let it stand until the bubbles disappear. Under diffuse light from the day. Observe the color of the sample against the light to see if it is transparent, whether there are mechanical impurities, impurity particles and other phenomena. 4.2 Curing test piece method
Take the cast test piece that meets the requirements for the determination of electrical strength performance, and observe with your eyes whether the color of the cast test piece is uniform and transparent, whether it is shiny, whether there are wrinkles and other phenomena.
5 Density
The density can be measured by placing the sample in a wide-mouthed pycnometer with a volume of not less than 25mL at 23±2℃. First, calibrate the volume of the pycnometer with distilled water or ionized water of the same purity, then put the sample in and weigh it, and calculate the density of the sample. The density can also be measured with a hydrometer. In case of dispute, the pycnometer method should be used. The median of the three measured values is used as the result, expressed in denominium/cm, taking one significant figure, and reporting the other two measured values at the same time. ..comThe method used shall be in accordance with the product standard.
6 Viscosity
GB/T 15023—94
According to Article 2.2 of GB1981-89. The adopted method is in accordance with the provisions of the product standard. 7 Gel avoidance time
7.1 Test device and equipment
a. Glass test tube, inner diameter 18mm, length about 180mm, b. Constant temperature bath device, temperature control accuracy ±1℃ c Gel time automatic tester, the instrument device drives a glass rod with a diameter of 6mm and a long enough length through an electric motor, and rotates around the axis at a low speed (1~2r/min). As time goes on, the viscosity of the sample gradually increases, thereby increasing the resistance to the glass rod. When the viscosity of the sample reaches 50Pa+s (or the viscosity value specified in the product standard), it stops rotating, and alarms and indicates the time. The basic components and principle examples of this type of instrument are shown in Figure 1.
d. Timer.
7.2 Test procedure
7.2.1 Automatic tester test method
First, preheat the test tube in a constant temperature bath at the temperature specified in the product standard for more than 5 minutes, then move in a sample about 75mm high, and immediately connect the measuring device for measurement. When connecting, the test tube should be placed vertically, the sample liquid level should be 10mm below the constant temperature bath liquid level, and the glass rod should be in the center of the test tube and reach 50mm below the sample liquid level. When the sample reaches gelation, the instrument automatically alarms and counts. 7.2.2 Manual test method
First, preheat the test tube in a constant temperature bath specified in the product standard for more than 5 minutes, then move in a sample about 75mm high, and start the timer to start counting. When the test tube is placed in the constant temperature bath, the sample liquid level should be 10mm below the constant temperature liquid level. During the test, use a 6mm diameter glass rod to slowly stir the sample up and down (be careful not to generate bubbles), and observe the changes in the sample at any time until the sample shows an initial gelling state, that is, when lumps appear, stop the timer, and this time is the gelling time. 7.3 Results
Carry out two tests and take the arithmetic mean of the two test values as the result, expressed in minutes. The difference between the two test values shall not exceed 5% of the mean value.
GB/T15023—94
Motor with speed reduction gear
Start of test
Position of platinum wire
(Top view)
End of test
Other positions when motor stops
Figure 1 Example of a suitable device for measuring gel time using a rotating glass rod Figure 1 Glass marking, 2—Glass rod, $6mm; 3—Test tube: 4—Constant temperature swing; 5—Adjustable height bracket: 6 Contact; 7—Insulating sheet: 8—Torsion wire, 9—Glass rod support; 10—Thin sheet shaft rotating at a speed of 1~2r/min, 11—Insulating joint, 12—Lead wire [Position at the end of the test) 8 Relationship between needle depth and time
8.1 Test device
Steel needle, as shown in Figure 2. The steel needle should meet the following requirements: diameter 1.00~1,02mm, the tip is symmetrically ground into a cone with a diameter of 5.9~6.7mm, the taper angle is 8°40~9°40°, the needle tip is cut off to make a flat-headed truncated cone with a diameter of 0.11~~0.16mm and a length of 5.0~5.8mm, it is finely ground and mounted on a coaxial and concentric brass handle. The needle rod of the needle penetrometer assembled on the needle penetrometer should be able to slide up and down along the vertical guide without significant friction. The mass of the moving part h
(i.e. the needle, needle rod and counterweight) should be 100±0.25g, and the needle penetration depth reading can be accurate to 0.1mml. c. Sample container, the bottom diameter of the container is 25mm, the top diameter is 37mm, and the height is 32mm. d
The timing device should ensure that the needle penetration time is 5.0±0.25.20't ~
GB/T15023-94
Figure 2 Needle of the needle penetrometer
B.2 Test procedure
Prepare the compound according to the composition specified in the product standard. The amount of the compound should be sufficient to fill the sample container. Before preparation, each component should be placed at 235℃ or the curing temperature specified in the product standard for 1 hour, and then the components should be mixed and pressed into the sample container. Be careful not to trap bubbles. The top surface of the sample should be in a horizontal state. Start measuring the needle penetration 5 minutes after the sample is mixed. Repeat the measurement at a certain time interval (depending on the curing speed of the sample) until the needle penetration is less than 0.5tmm. When measuring the penetration, slowly lower the sliding needle rod until the needle tip just touches the top surface of the sample. The measuring point should be more than 4mm away from the container and the previous measuring point. Record the reading on the needle penetration meter mark or adjust the indicator to zero (depending on the type of instrument used). Then quickly release the sliding rod and let it fall freely. After 5±0.2, read and record the penetration depth from the mark with an accuracy of 0.1mm. Observe carefully during the test. If any movement of the sample container is found, the test is invalid. Measure three samples.
8.3 Results
Draw a graph of the relationship between the penetration and time of each sample. 9 Exothermic temperature
According to GB7193.4. And make the following additional provisions: Before mixing, each component should be preheated to the bath temperature specified in the test. b. For general types of ester resin systems, the constant temperature bath temperature is 80℃. For other types of resin systems, the constant temperature bath temperature is in accordance with the product standards.
When the resin system reacts and releases only a small amount of heat, the sample volume can be increased. At this time, a 250ml long-necked round-bottom flask can be used, and the sample can be c
filled to the beginning of the long neck of the flask.
10 Storage stability
10.1 Viscosity change determination method
10.1.1 Storage in a closed container
10.1.1.1 Test equipment
+ drying oven, volume 50L. Natural ventilation
Sealed container, volume 250m1-, ground glass conical flask or metal container that is not easily corroded and inert to the sample can be used: h.
Viscometer, with a range suitable for measuring the viscosity range before and after storage. 10.1.1.2 Test procedure
GB/T15023-94
First, measure the initial viscosity of the sample at 23±1℃, then weigh 200±10g of the sample and put it into a sealable container. After confirming that the density is uniform, put it into a drying oven at 50±2℃ (or the temperature specified in the product standard). After 96h (or the time specified in the product standard), take it out and cool it to 23±1℃, and test the viscosity with the same viscometer used to test the initial viscosity. 10.1.1.3 Results
The stability is expressed as the multiple of viscosity increase after storage, calculated as follows: X, = n - n
Where: X,-
The multiple of viscosity increase after storage of the sample:
The initial viscosity of the sample;
The viscosity of the sample after storage.
10.1.2 Storage in bulk containers
10.1.2.1 Test equipment
Drying oven, volume 50L, natural ventilation;
Beaker, 500ml.,
C, viscometer, with a range suitable for measuring the viscosity range before and after storage. 10.1.2.2 Test procedure
First, measure the initial viscosity of the sample at 23±1℃, then weigh 350±10g of the sample and put it into the beaker. Put it into a dry box at 50±2℃ (or the temperature specified in the product standard), take it out after 96h (or the time specified in the product standard), cool it to 23±1℃, and test the viscosity with the same viscometer used to test the initial viscosity. If the active diluent used in the product is lost during storage, the lost diluent can be added by mass after the storage time is reached, and the viscosity can be measured after sufficient stirring. 10.1.2.3 Results
Stability is expressed as the times of viscosity increase after storage. Calculate as follows: X, = -
Where: X2
times of viscosity increase after storage;
initial viscosity of the sample;
——viscosity after storage.
10.2 Penetration change determination method
10.2.1 Test equipment
9. Penetration determination device, same as 8.1:
b. Drying oven, volume 5UL. Natural ventilation. 10.2.2 Test procedure
First, prepare the sample according to the method in 8.2, and determine the penetration of the sample at 23±1℃ according to this article. Then store the sample in the drying oven at the temperature specified in the product standard. After the time specified in the product standard, take it out and cool it to 23±1℃. Determine the penetration according to 8.2. 10.2.3 Results
Stability is expressed as the percentage of penetration reduction after storage. Calculate as follows: X
Percentage of penetration reduction after storage of the sample, %; where ￥—
L,—initial penetration of the sample, mm!
L—penetration of the sample after storage, mm.
11 Volatile content at high temperature
11.1 Test equipment
GB/T 15023—94
Weighing chair, as shown in Figure 3, the upper and lower plates are made of stainless steel plates or materials that are insensitive to the sample. Analysis of the average value 0001g1
c. Drying box, volume 50L, natural ventilation; d. Desiccator.
11.2 Test procedure
Place the weighing chair in a drying oven at 110±2℃ for 15 min, take it out and place it in a desiccator, cool it to room temperature, and weigh it to an accuracy of 0.001g. Place about 0.3g of the sample on the lower plate of the weighing chair and cover it immediately. Weigh the upper plate to an accuracy of 0.001g, then remove the upper plate and hang it on the bent rod, put it into a drying oven with natural ventilation at 110±2℃ for 15min (or treat it according to the temperature and time specified in the product standard), then remove the upper plate and put it back on the lower plate, then take out the weighing chair from the drying oven and put it into a desiccator to cool to room temperature. Weigh to an accuracy of 0.001g
Figure 3 Schematic diagram of weighing chair
T Upper and lower plate support frame; 2 Upper plate and hanging: 3 Lower plate
11.3 Results
The volatile content at high temperature is calculated using the following formula: X
-Volatile content, %:
Where X,-
mr - ms
Weighing chair mass, customer:
CB/T 15023--94
Before baking, weigh the total mass of the chair and the sample. After baking, weigh the total mass of the chair and the sample. Take the median of the three measurements as the result, take two significant figures, and report the other two measurements at the same time. 12 Ash content
According to GB 1747. Burning temperature 900±25C, time 2h or as specified in the product standard. 13 Filler content
13.1 Burning determination methodbzxZ.net
According to Chapter 12 of this standard. Burning temperature and time are as specified in the product standard. 13.2 Extraction determination method
Test equipment
Erlenmeyer flask, 100mL container
Sand core crucible and filtration device, sand core aperture number is G3 analytical balance, graduation value 0.001g;
Acetone, difluoromethane or solvent specified in the product label, chemically pure; T drying oven, natural flow;
Desiccator.
13.2.2 Test procedure
First, dry the sand core crucible in a T drying oven at 105±2℃ for 30 minutes, take it out and put it in a desiccator to cool to room temperature, and weigh it to an accuracy of 0.001g. Then weigh 3 ± 0.1 g of the sample, accurate to 0.001 g, put it into a conical flask, add 50 ml of acetone or methane or the bath agent specified in the product standard, stir to dissolve the submersible completely, then pour it into the weighed sand core crucible and filter to separate the filler and the solution. Wash the filler with 100 mL of solvent several times, dry the crucible containing the filler at 105 ± 2 °C or at a temperature suitable for the solvent used to constant weight (the change is no more than 0.01 g after 1 hour of drying time), and weigh it accurately to 0.001 g. 13.2.3 Result
The filler content is calculated by the following formula:
Where: Xs
The filler content is %1
m---the mass of the crucible, g;
m.---the mass of the sample, g
me ms × 100
The total mass of the crucible and the sample remaining after removal, m. The median of the measured values is taken as the result, rounding to two significant figures, and the other two measured values are reported at the same time. 14 Acid value
According to Appendix C of GB1981-89, the acid value of polyester resin shall be carried out according to (B 2895. 15 Hydroxyl content
The hydroxyl content of polyester resin shall be carried out according to GB 7193.2. 16 Epoxy equivalent
According to GB 4612.
17 Halogen content
According to Method A in GE7139.
18 Surface drying time
GB/T 15023—94
Perform according to Article 2.4 of GB1981-89. Weigh 5±0.1g of the sample and put it into a flat-bottomed aluminum foil container with a diameter of 75mm and a depth of about 8mm, covering the bottom of the container. Bake according to the temperature and time specified in the product standard. 19 Thin layer curing
19.1 Test equipment and instruments
Analytical balance, graduation value 0.001g
Conical flask with reflux condenser, volume 250mL; plain glass cloth, 50mm×150mm, standard weight 55~75g/m2. Density 19~24 root/cm; acetone or solvent specified in product standards, chemically pure; d
static weight thickness gauge, measuring head diameter 6~8mm, pressure 0.1MPa, graduation value 0.01mmf, drying oven, natural ventilation;
g. Desiccator.
19.2 Test procedure
19.2.1 Sample preparation
Put the glass cloth in a drying oven at 110±2℃ and dry it for 1h, then take it out and put it in a desiccator to cool to room temperature. Weigh it to an accuracy of 0.001g. Pour the glass cloth into the composite to be tested and shake it at any time to remove bubbles. After full immersion, take it out after about 5 minutes, and after dripping for 3 to 5 minutes, hang the sample vertically in a drying oven and cure it according to the temperature and time specified in the product standard. After the curing time is reached, take out the sample, put it in a desiccator to cool to room temperature, weigh it to an accuracy of 0.001g, and use a static weight thickness gauge to measure the thickness of the upper, middle and lower parts of the sample. 19.2.2 Measurement of soluble content in the sample
Put the prepared sample in a flask with a reflux condenser, add 50mL of acetone (or the solvent specified in the product standard), heat to boiling, and reflux at a slight boil for 1h, then, take out the soluble matter from the flask. Take out the sample, dry it at 80±2°C (or temperature suitable for the solvent used) for 2h, put it in a desiccator and cool it to room temperature, weigh it, and the accuracy is 0.001g. 19.3 Results
The thin layer curing property is expressed as the percentage of the soluble content in the cured sample to the amount of the cured sample, and is calculated as follows: mg-m
Where X.
Soluble content, %
Mass of glass cloth, g1
Total mass of impregnated composite and glass cloth·m; m.
-Total mass of impregnated composite and glass cloth after extraction + 8. X 100
Take the middle value of the three sample measurement values as the result, take two significant figures, and report the other two measurement values and the thickness of the upper, middle and lower parts of each test piece.
20 Thick layer curing
20.1 Method A Test cake observation method
Perform according to Article 2.7 of GB1981-89, the sample mass is about 10g? But it is necessary to ensure that the thickness of the sample after curing is greater than 4mm, and the curing temperature and time are in accordance with the product standard.
20. 2 Method B Hardness determination method
Perform according to Chapter 41 of this standard.
20.3 Method C Heat deformation temperature determination method under load is carried out according to Chapter 42 of this standard.
20.4 Method D Determination of soluble matter content
20.4.1 Test equipment and instruments
Analytical balance, graduation value 0.001g
Sieve, 45 mesh and 60 mesh;
GB/T15023-94
Conical flask with reflux condenser, capacity 250mL; acetone or solvent specified in product standards, chemically pure; sand core crucible and filtration device, sand core aperture number is G3; f. Flat drying box, natural ventilation;
Dryer.
20.4.2 Test procedure
First, dry the sand core crucible at 105±2℃ for 30min, take it out and put it in the dryer to cool to ambient temperature, weigh it, accurate to 0.001g. Then, the sample cake (thickness greater than 4mm) solidified at the temperature and time specified in the product standard is crushed and sieved, and 3±0.1g of the sample sieved with 45-mesh to 60-mesh sieve is weighed and placed in a conical flask, and 50mL of acetone or solvent specified in the product standard is added, heated to boiling, and refluxed for 1h at a slight boiling, and after cooling to room temperature, poured into a sand core of known mass, oil filtered, and the contents of the flask and crucible are washed with 100mL of the solvent used in multiple times. Then, the crucible is placed at 80±2℃ or the corresponding temperature of the solvent specified in the product standard, dried for 2h, taken out and placed in a lower desiccator to cool to room temperature, and weighed to an accuracy of 0.001g. 20.4.3 Results
Thick layer curing is expressed as the percentage of the soluble content of the cured sample to the amount of the cured sample, calculated as follows: X, = mu (m2 - mo)
Where: X—soluble content, %;
-cup mass g$
m:1——cured sample mass, g1
Total mass of the cured sample and glass after extraction, B. X 100
The median of the three sample measurements is taken as the result, with two significant figures, and the other two measurements are reported at the same time. 21 The effect of the compound on
According to Article 2.8 of GB1981-89. Only dip coating for one week. 22 The effect of the compound on the enameled wire
According to Article 2.11 of GB1981-89.
23 Diffusing resin
23.1 Test equipment
Spiral coil, preparation method is in accordance with 3.2.1 of GB1981-89. The type of enameled wire used depends on the heat resistance grade a of the composite.
and is selected according to Table 1.
Heat resistance index of the tested composite
Type of enameled wire for spiral coil
h. Balance, graduation value 0.01g;
c. Drying box, natural ventilation;
d. Dryer.
23.2 Test procedure
GB/T 15023—94
Polyesterimide
Polyimide or polyamideimide
First, place the spiral coil (inner diameter 6.3mm, length 75mm) in a medium at 105°C for 30min, take it out and put it in a desiccator to cool to room temperature, and weigh it to an accuracy of 0.01g. Then immerse the coil vertically into the compound and carefully move it to eliminate bubbles. After immersion for 5 minutes, take the coil out of the compound at a speed of 10 cm/min and hang it vertically in the room. After dripping for 3 to 5 minutes, hang it vertically in a dry coal box and cure it according to the temperature and time specified in the product standard. After curing, take it out and put it into a desiccator to cool to room temperature and weigh it to an accuracy of 0.01g. 23.3 Results
The impregnation resin melt volume is calculated as follows:
X, = mu - m13.
Where: X: melt volume, B,
m1s——helical coil mass, g+
Total mass of the impregnated spiral coil sample after curing·mm. The median value of the five sample measurements is taken as the result, accurate to 0.01g, and report the maximum and minimum values. 24 Total shrinkage
24.1 Test equipment
Tools. a, Analytical balance, graduation value 0.001g, fast tester with wide range projection scale; b, sinker, mass 25±5g, known volume at 23℃ and thermal expansion coefficient of the material used: silicone oil, known density at 23℃. Other liquids with known density that have no effect on the specimen may also be used; c, sample container.
24.2 Test procedure
24.2.1 Determination of density at the time of mixing start of high temperature curing composites Weigh the masses of the sinker and the hanging wire in a narrow atmosphere. .-(8)
For composites that react during mixing, heat each component of the sample separately to the curing temperature and then mix: the moment when each component starts mixing is taken as the starting point of time. Immediately after mixing, pour the composite into a sample container, and then suspend a sinker preheated to the curing temperature of the sample in the composite. Determine the apparent mass of the sinker (including the hanging wire) as a function of time. The time interval for determination depends on the curing reaction characteristics of the composite. Based on the data, determine the apparent mass of the sinker (including the hanging wire) at the starting point of time by graphical extrapolation. For composites that do not react when mixed without the addition of initiator, mix all components (except the initiator) together, heat to the curing temperature, and then pour into a sample container. Suspend the sinker heated to the curing temperature in the composite and determine the apparent mass of the sinker (including the hanging wire). Note: ① Peroxide initiators are not allowed to be heated due to the risk of explosion. The effect of a small amount of initiator (1 g to 2 g) on the density can be ignored. 24.2.2 Determination of the initial density of the composite cured at room temperature Measure the density of each component according to Chapter 5 of this standard. 24.2.3 Determination of density of cured castings
Weigh 25±5 of the mixed compound, pour it into a test tube with a release agent, and cure it at the temperature and time specified in the product standard. After curing, remove the test tube, remove the release agent, cool it in a desiccator to room temperature, weigh it to an accuracy of 0.001g, and then determine the apparent mass of the casting (including the hanging wire) and the apparent mass of the hanging wire in the silicone oil by the immersion method in silicone oil of known density at 23±0.5g. First, use filter paper GB/T 15023--94
to absorb the silicone oil on the casting, then thoroughly clean it with petroleum aldehyde, and then freeze it at 110±2℃ or the temperature specified in the product standard for 1h, take out the casting, put it in a desiccator and cool it to room temperature, and again determine the apparent mass of the casting in air and in silicone oil at 23±0.5℃. If the difference between the apparent mass of the postcured casting in air and the apparent mass in silicone oil varies by more than 0.2% of the difference obtained before the postcuring, repeat the scrubbing and postcuring operations until the change is less than 0.2%. 24.3 Calculation of density
24.3.1 Calculation of density at the start of mixing of high temperature curing composites 24.3.1.1 The volume of the sinker at the curing temperature is calculated as follows: V = Vz + 3dV23(T, 23) -
Where: V is the volume of the sinker at the curing temperature, cm\, Va is the volume of the sinker at 23°C, cm,
is the linear thermal expansion coefficient of the material used for the sinker, 1/°C; the curing temperature of the composite, °C.
24. 3. 1. 2
In the formula,
The initial density of the high-temperature curing composite mixture (%) is calculated according to the following formula: m+mu
The density of the composite at the beginning of mixing, g/cm\, the mass of the sinker·name:
The mass of the hanging wire, g,
The apparent mass of the sinker and the hanging wire in the composite at the starting time of mixing at the curing temperature, V
The volume of the sinker at the curing temperature, cm. 24.3.2 The density of the room temperature curing compound at the start of mixing (en) is calculated as follows: %
Where: Po
(ma + mB) X pa X Pu
(mA × Pp) + (m X Pa)
density of the compound at the start of mixing, g/cm2, mass of component A + mass of component B, g
density of component A, g/cm2,
density of component B, B/cm2.
24.3.3 Density of the solidified casting (ps) is calculated as follows: Pu
Where:
Density of the solidified casting +/cm
Mass of the solidified casting + BE
Apparent mass of the hanging wire in silicone oil
24.4 Results
Apparent mass of the solidified casting and hanging wire in silicone oil, g: density of silicone oil at 23°C/cm2.
..(12)
The total shrinkage is expressed as the percentage of the density of the composite at the beginning of the mixing of the components and the change in the density of the solidified casting at 23°C to the density of the composite at the beginning of the mixing of the components, and is calculated as follows: X. == × 100
Or where: X-total shrinkage, %:
Density of the composite at the beginning of the mixing, g/cm*; 13)2 The density of the room temperature curing compound at the beginning of mixing (en) is calculated according to the following formula: %
Wherein: Po
(ma + mB) X pa X Pu
(mA × Pp) + (m X Pa)
density of the compound at the beginning of mixing, g/cm2, mass of component A + mass of component B, g
density of component A, g/cm2,
density of component B, B/cm2.
24.3.3 Density of the solidified casting (ps) is calculated as follows: Pu
Where:
Density of the solidified casting +/cm
Mass of the solidified casting + BE
Apparent mass of the hanging wire in silicone oil
24.4 Results
Apparent mass of the solidified casting and hanging wire in silicone oil, g: density of silicone oil at 23°C/cm2.
..(12)
The total shrinkage is expressed as the percentage of the density of the composite at the beginning of the mixing of the components and the change in the density of the solidified casting at 23°C to the density of the composite at the beginning of the mixing of the components, and is calculated as follows: X. == × 100
Or where: X-total shrinkage, %:
Density of the composite at the beginning of the mixing, g/cm*; 13)2 The density of the room temperature curing compound at the beginning of mixing (en) is calculated according to the following formula: %
Wherein: Po
(ma + mB) X pa X Pu
(mA × Pp) + (m X Pa)
density of the compound at the beginning of mixing, g/cm2, mass of component A + mass of component B, g
density of component A, g/cm2,
density of component B, B/cm2.
24.3.3 Density of the solidified casting (ps) is calculated as follows: Pu
Where:
Density of the solidified casting +/cm
Mass of the solidified casting + BE
Apparent mass of the hanging wire in silicone oil
24.4 Results
Apparent mass of the solidified casting and hanging wire in silicone oil, g: density of silicone oil at 23°C/cm2.
..(12)
The total shrinkage is expressed as the percentage of the density of the composite at the beginning of the mixing of the components and the change in the density of the solidified casting at 23°C to the density of the composite at the beginning of the mixing of the components, and is calculated as follows: X. == × 100
Or where: X-total shrinkage, %:
Density of the composite at the beginning of the mixing, g/cm*; 13)
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