Haolisen: Types of oil pollution in electrophoretic coatings and corresponding test methods

In the control of electrophoretic coating process, oil pollution control is a very important part.

Electrophoretic coating will be exposed to different sources of oil in different processes, which will eventually lead to the corresponding oily molecules in or on the surface of the electrophoretic wet film.

According to the source stage of the oil pollution, it can be roughly divided into electrophoresis wet film before and after electrophoresis wet film.

The oil stains on the base material are mainly the metal anti-rust oil during the delivery and transportation of the metal white billet, the drawing oil in the stamping and welding process, the cutting oil and a small amount of metal base material cleaning oil (such as the use of gasoline for heavy oil pre-wiping )

The viscosity of this type of oil is relatively low, most of which are usually removed by degreasing and water washing in the pre-treatment process, but a small amount is left on the metal white blank due to the poor degreasing cleaning effect and the complex cleaning of the flange gap and the internal cavity structure.

Electrophoretic coating line transmission system usually adopts chain suspension transfer or ground chain skid for transfer.

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According to different types of oil pollution and pollution process, there are usually two test methods: grease-electrophoresis bath co-dissolution test and grease-electrophoretic paint film co-baking test to evaluate the matching performance of electrophoretic coatings and oil products

For liquid oils brought into the electrophoresis tank: lipid oils are diluted 1:1 with ether solvents, and liquids such as metal anti-rust oil, drawing oil for stamping and welding processes, cutting oil, and a small amount of metal substrate cleaning oil are used.

Co-baking test is used for oils on the surface of contaminated electrophoresis wet film (such as high-temperature chain grease): two standard plates are electrophoresed with 20μm film thickness and dried for 3-5 minutes; the specified amount of oil sample (usually liquid oil) Take 1ml and 1g of lipid oil) drop them on the aluminum watch glass, place the aluminum watch glass with the oil sample in the center of the electrophoresis wet film sample plate, and place the electrophoresis wet film sample plate together with the watch glass in the oven.

Haolisen Application Engineering Center Li Shuangjie