introduction
In the paint and varnish industry, the hardness of the paint film is a key performance parameter. Knowing the hardness of the paint film helps manufacturers determine the quality and durability of their products, as well as their suitability in different application environments. This article will introduce a method of measuring the hardness of paint film described in ISO 1522:1998 (E) standard, that is, the pendulum rod damping test, including the test principle, required materials and instruments, operation points, result expression, precautions, influencing factors and instrument calibration.

Test method for damping of pendulum rod
Test principle

The pendulum damping test in ISO 1522 has the same principle as the pendulum damping test in GB/T 1730 mentioned earlier. It measures the hardness of the paint film by placing the pendulum rod on the surface of the paint film template and recording the decay time of the swing when the pendulum rod swings at a certain Angle. According to the attenuation time of the swing, the hardness of the paint film can be determined, and the longer the attenuation time of the swing, the higher the hardness of the paint film.

Test method for damping of pendulum rods for paints and varnishes according to ISO 1522

Materials and equipment

Pendulum rod damping hardness tester: Different types of pendulum rod damping hardness tester can be used, such as Koenig pendulum or Posasz pendulum.

Metal or glass plates: used as test plates, with dimensions close to 100mm x 100mm x 5mm.

Operating essentials

Place the coating side of the test plate on the instrument table.

Gently place the pendulum bar on the surface of the test plate to deflect it to the appropriate Angle (6° for Koenig and 12% for Persazz).

Start the stopwatch or other timing device at the same time and record the time of the swing from 6° to 3° (Koenig pendulum) or from 12° to 4° (Posazz pendulum), in seconds.

Result representation

According to ISO 1522, tests need to be carried out at three different locations on the same test plate, and the results of each measurement are recorded, and finally the average of the three measurements is calculated. This average will represent the pendulum damping hardness of the coating.

Matters needing attention

The considerations in ISO 1522 are similar to those in the previously mentioned GB/T 1730 standard and include:

Check the condition of the instrument and the appearance of the material regularly to ensure the accuracy of the test.

The operation process must be careful, especially when swinging the pendulum, a small movement can affect the result.

Test method for damping of pendulum rods for paints and varnishes according to ISO 1522

Influencing factor

The factors that affect the results of the film hardness test are also mentioned in the ISO 1522 standard, including film thickness, temperature and humidity, air flow, and material appearance. These factors need to be taken into account during testing to ensure an accurate hardness value is obtained.

Instrument calibration

The ISO 1522 standard mentions the importance of instrument calibration to ensure the accuracy of test results. The standard swing time of Koenig pendulum and Persazz pendulum has a specified value, and the calibration of the instrument can be achieved by adjusting the position of the weight.

conclusion
Pendulum bar damping test is a standardized method for measuring the hardness of paint and varnish film, its principle, required materials and instruments, operation points, result expression, precautions, influencing factors and instrument calibration are detailed in ISO 1522:1998 (E) standard. Understanding and controlling the hardness of the film is essential to ensure the performance and quality of paints and varnishes, so this test method has important application value in the coatings industry.