Introduction of determination method of anti-wear strength of film

Determination of the abrasion resistance of the coating film with sandpaper

For rapid testing, a simple method that does not require any special equipment can be utilized.

Paint the paint sample on a glass plate with a size of 130x180 mm according to the technical conditions. After drying, use water-resistant sandpaper and a considerable amount of water to sand and coat the film until the glass surface is exposed; this grinding process is carried out using a wooden block with a grinding surface of 50x80 mm, on which are fixed the same dimensions (50x:80 mm) rubber (or leather) sharp pad, and 150 water-resistant sandpaper is placed on the lining. Use a wooden block with a weight of 2 hectares, and move it parallelly along the long side of the test plate from one end to the other end in a flat and non-vibrating motion by hand for grinding. (Related instruments: Abrasion Tester)

In this way, the number of reciprocating movements required to fully expose the glass surface is a sign of the abrasion resistance of the coating film. For example, an air-dried coating film made of aldehyde resin should be able to withstand 10 to 12 reciprocating movements without damage; a dried coating film made of oil-modified phenolic resin should be able to withstand more than 40 times. back and forth movement. (Related instrument: oven)

In order to measure the abrasion resistance of the coating film, the following C.H_Serebryannikov 67 instrument (see page 436) can also be used. This instrument was originally proposed by the author for testing putty; in this case, a wooden board with friction materials (linen, rubber, leather, etc.) fixed on it can be used instead of pumice.

Determination of abrasion resistance of coating film by pressure

The wear strength of the paint film can be determined by the damage of the carborundum particles (or sand grains) punched out of the nozzle under the pressure of the compacting air to the paint film. For example, adjusting the air pressure flushed out of the nozzle can change the jet flow speed of emery grains. The emery powder should all be composed of particles with a diameter of about 0.008 mm.

Abrasion strength is measured directly from the weight of corundum necessary to completely destroy the paint film.

If the thickness of the paint film is known (relevant instrument: Thickness Gauge), the weight of emery necessary to damage the unit thickness of the paint film can be calculated .

If a nozzle of a certain size, a certain compressed air pressure, emery grains of a certain size, shape and hardness are used, and a certain distance between the tested paint film and the nozzle is used, comparable results can be obtained (the range is from ± 10%) to ±2.5%).