Coating technology of the hottest liquid film for

2022-07-26
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Liquid lamination: coating technology for print protection for silk printing plants that have introduced large format inkjet equipment, the lamination machine has become a necessary post press processing equipment. The original purpose of the lamination is to set up a barrier between the printed images, so as to prevent them from being worn in the process of reuse. The laminating machine used in the printing industry mainly covers a layer of film on the surface of the printed matter to prevent the image from being scratched and damaged by chemicals. However, the laminating machine has another use, that is, to apply a layer of protective liquid paint to the printed matter. Liquid coating technology is the focus of this article. We will focus on introducing the equipment, coating type, application scope and benefits related to this post press processing process

liquid laminating machine

liquid laminating machine is actually a coating equipment. From the most basic point of view, the printed matter must first be input into the laminating machine, then coated, and finally input. The intermediate and final steps of coating mainly depend on the type of coating you choose. It can be either UV curable coating or water-based or solvent-based coating. For example, the substrate that has been UV coated must be treated by the drying unit before output, while the substrate coated with water-based coating can choose to add an infrared drying program according to the automation level of the laminating machine to enhance the drying effect of the printed matter.

in order to meet the different needs of users, the liquid laminating machine also has a variety of different configurations and sizes. Problems needing attention in storage and operation of electronic universal testing machine in today's printing market, people can choose either manual or automatic laminating machine, or laminating machine using sheet fed or web paper

uv laminating machine is generally divided into reverse roll or three roll system. The water-based laminating machine generally applies the coating to the substrate, and then uses a screw rod (that is, a cylindrical measuring rod) to reduce the thickness of the coating to an appropriate level. The paint can be scraped off the back of the substrate with an ink scraper or similar equipment

Ikeharris, President of Daige, said: This is not roll coating, but wiping the coating on the substrate. When people need precise coating, they need to use the special measuring rod commonly used in the laboratory. In addition, the metering rod is also suitable for the water-based coating process of manual and large roll to roll coaters. It enables the coater to produce a smooth and uniform coating on the substrate

roller coater uses multiple ink rollers to transfer printing images and complete the task of coating them. From entering the roll coater, the substrate is either dried by ultraviolet or infrared rays, or dried by natural air, but the latter takes a long time. The substrate conveyor integrated with some coaters usually conveys the coated substrate to the drying or curing system in time. As an alternative, the water-based coated image can also be placed horizontally to make it dry faster. This method is usually used in manual coater. Harris points out that the water-based coating needs about 20 to 25 minutes of drying time

many UV liquid laminating machines recently launched can cure the coating at high speed, sometimes as high as 100 feet/minute. In addition, they can also be designed to be very small to save space. For example, the total length of the equipment can be controlled within 5 feet, including the length of the conveyor, because only in this way can the laminating machine process the materials quickly

the characteristics and quantity of live parts determine the type of liquid laminating machine you need. If you want to print banner patterns on lattice plastics or pop images on textiles, you'd better choose a water-based coating system because the depressions on the printed surface of the material must be filled with liquid paint

protective coating and its application

with the increasing awareness of environmental protection in printing plants, UV coating has been quickly recognized by people in recent years. At present, most of the UV coatings used for printing images do not contain VOC (volatile organic compounds), so they can not volatilize any, but the following are worthy of attention: 1. The growth rate of automobile production and sales volume with the largest weight in the total industrial volume is picking up; 2. The accumulated orders of key enterprises in the machinery industry can be easily transformed into solid under the premise of warming gas. Water based coating is generally composed of 70% water and 30% resin, so it needs to be placed for a long time after coating, so that the water can be evaporated before the substrate is rolled up or stacked. Tatum believes that people should consider the evaporation factor when calculating the cost of water-based coating

the advantages of water-based coating mainly come from the latest progress in formulation technology. Just a few years ago, the VOC content in water-based coatings was as high as lb/gal. Nowadays, the VOC content of many coatings has decreased significantly. According to Tatum, the high VOC content is one of the main reasons for the yellowing of printed images. Therefore, he suggested that people use non stearate resin in water-based coatings to reduce the content of solvent

although water-based and UV curable coatings have made great progress, solvent based coatings still occupy a place in the liquid coating market. Davidconrad, equipment product manager of neschen USA, said that solvent based coating still occupies a dominant position in the field of label production. Flexible panels are most suitable for solvent based coating, because this coating can prevent the image from becoming brittle or cracking over time. The products printed on hard substrate are more suitable for UV coating, because UV coating does not have the ductility shown by other coatings, and because of this, this coating is not suitable for providing protection for the body image (below)

the body image needs to be coated with ductile materials, because this coating must be able to adapt to rivets, curved surfaces and other special surface conditions. The body image shown in the figure uses water-based liquid coating. Tatum explained that to protect the images of vehicles and ships, the paint you use must have at least 150% elongation. Because it needs to take care of rivets, intricate curves and other irregular printing surfaces. In this case, once the coating breaks, the printed image will collapse. Generally speaking, people should choose water-based or soluble coating for the substrate according to its requirements for coverage or flexibility, which can obtain the curve and data of the experimental process in real time. In addition, it should also be kept in mind that the high solid content in UV coatings is not conducive to their use in textiles and other special substrates. Speaking of this, we must remind those who intend to use inkjet printers to produce exquisite works of art and photography: you should pay special attention to using liquid laminating machines to protect printed images

waterproof canvas needs water-based coating. This kind of canvas can absorb a lot of ink, so there is almost no water fault. Manelski points out that images printed on waterproof canvases are difficult to maintain for a long time without liquid coating

another kind of canvas is called bentonite canvas, which needs to be coated with a layer of solvent based materials on the surface of the substrate, because the ink penetrating the surface of the substrate is prone to water intrusion under the influence of the surrounding moisture. Although the swelling canvas is more prone to this failure than the water-resistant canvas

other products suitable for liquid compliance include doors, furniture, walls, decorations and food packaging. For the above products and those printing images with traditional uses, you must be very careful when selecting the coating formula. Now let's focus on the effective methods of selecting coatings for printed matter

choose the right liquid

as we all know, UV can cure UV ink and coating, but it will also prevent UV liquid coating from providing protection for printed images. Any kind of UV inhibitor will affect the curing of the coating. Therefore, the original purpose of UV liquid coating is to prevent printing images from being scratched and scratched. Tatum pointed out that the UV curing coating works very well on the images produced by UV inkjet printers. He said that in most cases, the water-based coating is not suitable for UV inkjet printing, because the cured UV ink can form a non stick surface

another problem needing attention is that water-based liquid coatings, like water-based silk printing inks, also contain certain solvents. We mentioned earlier that the VOC content in these coatings will decrease with the passage of time, but even so, you should keep a chemical safety technical manual for each water-based coating you use

solvent based liquid coating is mostly used in water-based printing. Their formulations can contain UV absorbers and stabilizers to prevent polymer aging caused by photooxidation and high temperature. Solvent based coating can also contain some leveling agents, which can improve the surface smoothness of the coating

cost factor

the cost of replacing plastic film with liquid coating is a problem worthy of attention. According to Conrad, the cost of protecting images with liquid film is about 0 USD 03/m2 (display image for short-term use) or 0 38 USD/m2 (long-term images printed on demand)

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