JB/T 10442.2-2017Insulating paper coated with resin binder forming rhombic pattern for electrical purposes - Part 2: Methods of test (English PDF)

5.4.1 Adhesive thickness of single-sided coating products

The median value of the thickness, which is measured in 5.2, minus the median value of the thickness, which is measured in 5.3, to get the adhesive thickness of the single-sided coating product, in micrometers (µm).

5.4.2 Adhesive thickness of double-sided coating products

The median value of the thickness, which is measured in 5.2, minus the median value of the thickness, which is measured in 5.3; THEN, it is divided by 2, to get the adhesive thickness of the double-sided coating product, in micrometers (µm).

6.1 Instruments and tools

The instruments and tools used in the test are as follows:

- Analytical balance: Sensitivity is 0.001 g;

- Constant pressure thickness gauge: Same as the requirements in 5.1;

- Steel ruler: The graduation value is 0.5 mm;

- Sampling plate: 100 mm x 100 mm.

6.2 Specimen

Cut three specimens of 100 mm x 100 mm, by the sampling plate, at even interval at least 20 mm from the edge of the paper roll width.

6.3 Test procedure

6.3.1 Weigh the mass m1 of each specimen, accurate to 0.001 g. Measure the length, width, thickness of the specimen, in millimeters (mm).

6.3.2 The tightness is calculated according to formula (1).

Where:

rho - The tightness of the specimen, in grams per cubic centimeter (g/cm3); m1 - The mass of the specimen, in grams (g); in grams (g); m4 - The mass of the specimen container plus the specimen, after baking, in grams (g); m2 - The mass of the specimen container, in grams (g).

7.4 Results

Take the median of the three tests as the result. Report the maximum and minimum values, accurate to 0.1%.

8.1 Instruments and equipment

The instruments and equipment used in the test are as follows:

- Balance: Sensitivity is 0.0001 g;

- High temperature furnace: The temperature control accuracy is ±25°C;

- Crucible.

8.2 Specimen

According to the provisions of 7.2, cut 3 specimens, each of which is about 2 g ~ 5 g. Remove the moisture according to the baking conditions for measuring the moisture. It may also use 2 g of dry specimen, that has not been exposed to moisture after measuring the moisture.

8.3 Test procedure

Burn the crucible at 925°C ± 25°C in advance. Take it out and put it in a desiccator. After cooling to room temperature, weigh it (m5). Then add the dried specimen. Weigh it (m6). Burn it to carbonize. Then move it into a high-temperature furnace. Burn it at 925°C ± 25°C for 2 hours. Take out the crucible.

Cool it in a desiccator. Weigh it (m7). If necessary, the burning can be repeated, until the weight is constant. All measurements shall be accurate to 0.0001 g. The ash content is calculated according to formula (3).

Where: Ac - Ash content of the specimen, %; follows:

- Analytical balance: The sensitivity is 0.001 g;

- Oven: The temperature control accuracy is ±2°C;

- Sample container: Stainless steel tank;

- Transformer oil: According to the requirements of GB 2536.

11.2 Specimen

Take three 75 mm x 75 mm specimens, which are at even interval at least 20 mm from the edge of the paper roll width.

11.3 Test procedure

Put the specimen in the oven. Heat up to 105°C ± 2°C. Keep it for 2 h. Take it out and put it in a desiccator, to cool to room temperature. Weigh it (m8). Then dry it in an oven at 105°C ± 2°C for 20 minutes. Take it out and immediately immerse it in transformer oil, which was preheated to 90°C ± 2°C. Then cool to room temperature. Take out the specimen. Use filter paper to quickly absorb the excess oil from the surface. Weigh it (m9). The oil absorption is calculated according to formula (4).

Where:

Oa - Oil absorption of specimen, %; m9 - The mass of the specimen after oil absorption, in grams (g); m8 - The mass of the specimen before oil absorption, in grams (g).

11.4 Results

Take the median of the three tests as the result of oil absorption. Report the maximum and minimum values.

12.1 Equipment

The equipment used in the test is as follows:

Constant-speed mobile testing machine: The speed can be adjusted, to make E - The elongation at break of the specimen, %;

delta L - The increase in length of the specimen when it breaks, in millimeters (mm);

L - The initial length of the specimen between the clamps, in millimeters (mm).

12.4 Results

Take the median of nine test data, in each direction, as the result of tensile strength or elongation at break. Report the maximum and minimum values.

14.1 Equipment and instruments

The equipment and instruments used in the test are as follows:

- Oven: The temperature control accuracy is ± 2°C;

- Constant-speed mobile material testing machine: The speed can be adjusted to 5 mm/min. The graduation value is 10% of the value required by the individual material specifications. The testing machine is equipped with a test heating box, which has a temperature control accuracy of ±2°C.

14.2 Preparation of specimens

Take two flat, smooth, clean aluminum or copper plates, which have a thickness of 0.5 ~ 1.0 mm, a width of 50 mm, a length of about 150 mm; overlap with each other for 50 mm along the direction parallel to the long axis. Clamp 4 layers of specimen, which has a size of 50 mm x 50 mm. Apply a pressure of 15 kPa on the surface of the overlap joint. Cure it according to the curing conditions specified in Chapter 3 (Be careful to prevent the poor contact, BETWEEN the metal plate AND the specimen, or BETWEEN the specimen AND specimen, due to the upwarp of the metal plate, during the operation). Prepare 5 specimens. […]

14.3 Test procedure