Why do we need to spray a layer of primer first to print patterns on the surface of stainless steel water cups?

Recently, some of our articles have been highly displayed on a certain platform. Although the platform later restricted the flow due to hidden advertisements and other reasons, we still received many messages from readers and friends. One of the problems was that multiple purchases were made. Some surface patterns of thermos cups will gradually fall off when cleaned, but others will not. What is the reason for this?

The content that needs to be answered for this question is already included in today’s title, but it does not fully represent today’s title. To answer this question, we need to answer the second question first. Is it possible not to spray primer before printing patterns on the surface of stainless steel water cups? The answer is yes, you can print patterns without spraying primer. Well, please note that this question only answers that you can print patterns without spraying primer.

Why should we spray a layer of primer before printing patterns on the surface of stainless steel water cups?

It is necessary to spray a layer of white primer to print large-area patterns on the surface of stainless steel water cups. There are two reasons for this. One reason is to make the color of the packaging pattern realistic. If the surface of the stainless steel water cup is not sprayed with paint, the color will be silver-gray with metallic luster. Friends who have some knowledge of the printing process will know that if the saturation of the printing color is to be the original color, it must be printed in white. Any color other than white must be printed. Both colors as the background color will cause a color cast in the printed pattern. If printed directly on the surface of an unsprayed stainless steel water cup, the printed pattern will be obviously dark.

Another reason is to make the pattern stronger so that the pattern will not fall off during cleaning as mentioned in the message. Printing on the primer has special requirements for the ink. More inks will be matched with the primer. In this way, not only the color restoration can be achieved after printing, but also the adhesion between the pattern and the paint can be achieved.

If there is a conflict between the primer and the ink, it will easily fall off. In order to avoid the mismatch, some factories must match it every time. Not only do they need to continuously test the materials, but they also require a lot of time and cost. Pay), the pattern will be printed on the surface of the water cup and then sprayed with varnish. After baking at high temperature, the pattern will be printed on the inner layer and will not come into contact with water, detergent, etc. The varnish on the surface plays a protective role.