Editor's note: Liquid coating allows print service providers to protect prints at the most competitive cost, with minimal waste and with minimal labor. This article will focus on introducing the scope of application of this technology.
For screen printers that have introduced large-format inkjet devices, laminators have become a must-have for postpress equipment. The original purpose of the film was to provide a barrier between the printed images to prevent them from being worn out during repeated use. The laminating machine used in the printing industry is mainly to cover the surface of the printed product with a film to prevent the image from being scratched and damaged by chemicals. However, there is another use for the laminator, which is to apply a protective liquid coating to the print. Liquid film coating technology is the focus of this article, we will focus on to introduce the equipment, coating type, application range and its benefits related to this postpress process.
Liquid coating machine
The liquid laminator is actually a coating device. From the most basic point of view, the print must first be fed into the laminator, then coated, and finally entered. The intermediate and final steps in the lamination process depend primarily on the type of coating you choose. It can be either a UV-curable coating or an aqueous or solvent-based coating. For example, substrates that have undergone UV coating must be processed by the drying unit prior to export, while substrates coated with water-based coatings can be selected to add an infrared drying process based on the automation level of the laminator. Enhances the drying effect of prints.
In order to meet the different needs of users, liquid laminating machines also have a variety of different configurations and sizes. In today's printing market, people can choose manual or automatic laminating machines, or they can choose to use sheet-fed or web laminating machines.
UV laminating machines are generally classified as reverse roller or three-roll systems. Aqueous laminating machines generally apply the coating to a substrate, and then use a wire rod (a cylindrical metering rod) to reduce the thickness of the coating to a suitable level. A squeegee or similar device can be used to scrape off the paint from the back of the substrate.
Ike Harris, president of Daige, said: “This is not a roller coating but a wipe on the substrate. When people need precise coating, special metering is often used in the laboratory. In addition, this metering rod is also suitable for use in the aqueous coating process of manual and large roll-to-roll coaters, which enables the coater to produce a smooth and uniform coating on the substrate. The coating."
Roller coaters can use multiple ink rollers to transfer printed images and complete the task of coating them. From entering the roll coater, the substrate is either dried by UV or IR, or dried naturally, but the latter takes a long time. Printer transporters integrated with some coaters—usually conveyor belts—feed the coated substrates in a timely manner to a drying or curing system. As an alternative, one can also place the aqueous coated image horizontally so that it dries faster. This method is usually used on manual coaters. Harris pointed out that waterborne coatings take about 20 to 25 minutes to dry.
Many recently introduced UV liquid laminators can cure coatings at high speeds, sometimes at speeds of up to 100 feet per minute. In addition, they can also be designed to be very compact in order to achieve space-saving purposes. For example, the total length of such a device can be controlled within 5 feet, which also includes the length of the conveyor, because only then can the laminator quickly process the material.
The characteristics and number of jobs determine the type of liquid laminator you need. If you want to print a banner pattern on grid plastic or print POP images on textiles, it is best to choose an aqueous coating system because the depressions in the printed surface of the material must be filled with liquid paint.
According to Jim Tatum, president of Advanced Finishing Solutions, the use of a UV liquid laminator to machine this textile material is not optimal because the laminating equipment will apply it to the print at very high speeds. A thin layer of paint. Under given operating parameters, this coating has almost no chance of filling the depressions on the surface of the substrate.
Tatum pointed out: "In this way, only part of the images you have obtained has been coated and cured. When severe weather conditions and other destructive factors occur, the coating will not protect the image at all." On the other hand, the aqueous liquid laminating machine evenly coats the surface of the substrate with the coating, so that the depressions in the image can also be properly protected.