Plastic hose printing process: dust → surface pretreatment → printing (UV ink) → polishing → Varnish UV curing (or heat curing).Offset Printing Tubes Plastic Laminated Tube Tube
1. Dust removal
One of the common problems with plastic raw materials is the easy generation of static electricity. During the production of the hose, the polyethylene material is constantly rubbing with the metal mold, causing the surface of the hose to generate static electricity, which makes the surface of the hose easy to adsorb dust. Need to first dust treatment.
2. Surface pretreatment
Since polyethylene is a nonpolar material, surface pretreatment is required prior to printing. There are two main ways to deal with: one is corona treatment, the other is the flame treatment, these two methods can be achieved so that ink and varnish attached to a solid purpose. Typically, the hose is required to have a surface tension of 3.6 x 10-2 N / m after surface treatment, and the specific values are related to the characteristics of the ink and varnish used.
Hose printing offset press is different from what we usually call offset presses. Generally speaking, offset printing plate for the lithography, the use of ink immiscible principle of the ink supply plate, and then transferred to the blanket printing plate, although now the development of waterless offset, but the plate is still lithography. The offset printing plate for the hose printing plate is the letterpress, so the more accurate name should be letterpress offset printing.
The hose is fed from the bottom oven and sent to the mandrel. The hose is printed on the right side of the rubber roller and passes through the conveyor belt to enter the drying process. Throughout the printing job, the press precision, ink, printing roll, printing Blanket, printing plate quality is good or bad, the adjustment is correct, a direct impact on the hose printing quality.Offset Printing Tubes Plastic Laminated Tube Tube
(1) the accuracy of the press. All printed mandrels should be of the same diameter and must be on the same circumference of the disc.
(2) ink. Hose printing ink its good oxidation resistance, strong adhesion, high fineness, good flow transfer.
(3) printing roll. Printing roller in addition to metal roll, there are nitrile rubber roller and resin roller, the surface is smooth, smooth, high roundness.Offset Printing Tubes Plastic Laminated Tube Tube
(4) printed version. Hose offset printing is usually used light curing resin plate, through the main exposure, development, washing, drying, after exposure and other processes to complete. A plate production time is about 30 - 40min, resistance to India to more than 100,000. The installation of the printing plate must be consistent with the printing direction, otherwise it will cause the pattern to tilt. Because this plate is a resin plate, and the graphic part of the raised slightly (about 0.5-0.6mm), in the production of mesh version, the high light part can only retain more than 5% of the network, so the hose on the printing The pattern is not so fine as the offset, and it is for this reason that there has been a phenomenon of direct printing on the hoses of the label instead of marking on the hose.
(5) adjustment. Including the viscosity of the ink, the pressure between the ink supply, the bottom roller and the printing plate, the pressure between the printing plate and the air cushion blanket, the pressure between the rubber band and the hose. Ink viscosity and supply of the adjustment must be based on the different changes in the figure to make the corresponding changes. For small text and dot printing, the ink viscosity should be properly increased, the amount of ink to be appropriate to reduce; for large field printing is the opposite.
(6) bottom rubber roller. And the pressure between the printing plate shall not be too large, otherwise it will cause the dot to increase the paste version. For small text and outlets in India, the pressure should be appropriately reduced; a large area of field printing may be appropriate to increase the pressure. If a printing can not achieve the printing effect, you can use two printing methods, but must consider the registration problem.