In gravure pad printing, people are eager to find a way to increase the resolution of print resistance and increase printing productivity and efficiency. UV ink in gravure printing in the end played what role? Which process can it use for gravure pad printing? How is it different from traditional ink?
First, the versatility of gravure pad printing is due to the uniqueness of the printing ink used and the uniqueness of the image transfer method. Unlike screen printing inks and offset printing inks, pad printing inks undergo several rheological states when printed on a substrate print. Correctly formulated inks should not only have good ink transferability, but also have high print resolution and high print speeds.
From the point of view of the development of pad printing inks, pad printing inks include a series of solvent-based formulations, which also include traditional solvent-based inks that are dried by evaporation and oxidation. However, there has recently been a UV drying ink that has the advantages of rapid drying and high resolution and performance of screen printing inks and offset inks. Today, substrates with convex and concave surfaces, such as three-dimensional metals, glass, and plastics, will become objects of UV-drying inks.
1, UV technology and gravure pad printing
UV drying appeared in the automobile painting industry as early as the 1950s, moved to the screen printing market in the 1960s, and occupied a large market share in screen printing in the 1970s. Currently, UV-dried photopolymers include not only inks but also adhesives, silicon-based release agents, pressure sensitive adhesives, and other coatings.
In pad printing, UV drying ink allows users to obtain fine print images, and the image has the characteristics of fast drying, high abrasion resistance, good pressure resistance, and strong solvent resistance. According to the specific ink instructions, if combined with some advanced equipment, UV technology will be fully utilized. Note: Improvements in the equipment include a high degree of automation, advanced time control in the printing process, an improved tight ink tank design, and an automatic ink cleaning device. With this improvement, UV printing will be most widely applied.
2, the rheology of printing ink
Pad printing inks, like solvent inks, have certain requirements for rheology. During the printing process, the ink is applied to the printing plate, excess ink is removed by the doctor blade, and the recessed area on the printing plate is filled with ink. After transferring to the printing pad, the ink thickened as the solvent evaporated. The rheology has changed and the viscosity of the ink has increased. In contact with the substrate, the ink is separated from the print head and transferred to the surface of the substrate.
3, UV drying ink drying
As mentioned earlier, solvent-based pad printing inks are dried by solvent evaporation. In addition, the epoxy-type ink can be oxidatively cross-linked and cured and dried under heating to obtain a large molecular weight. UV pad printing inks are similar to epoxy inks, but they are not dried under heat but dried under UV energy. In high-intensity UV energy, UV inks can be instantly cross-linked and dried.
When UV energy passes through the ink layer, the photosensitive molecules in the ink will interact with adjacent molecules. These single molecules are called monomers and oligomers. The inter-monomer effect causes linkages that make up the molecular matrix. The entire reaction process takes only a few seconds. And if the ink formulation is accurate, inks that add more pigment will also dry quickly. The dried product has higher resistance and solvent resistance than the oxidation-dried product.
So how to get the most effective UV energy is a mercury lamp under moderate pressure. The energy output of this kind of lamp may pass through a variety of metal materials and can output various specific wavelengths.
UV pad printing inks can also be printed on heat-sensitive materials such as ABS, polystyrene and plastics. When printing these materials, it is best to have a dichromatic reflective device as an aid. This device can absorb the infrared light energy and reflect the required UV light energy, which can reduce the temperature of the printing surface and increase the UV light energy. double effect.
4, the comparison of traditional inks and UV inks
If the printing job is large and the solvent resistance and abrasion resistance requirements are high, using UV drying pad printing ink is undoubtedly the best choice. In general, UV-drying inks have greater wear resistance than conventional or epoxy inks. The best example is the symbol on each key on the computer keyboard. They are all hit by a keyboard printed with UV ink. As a result, the traditional ink printed keyboard symbols wear out about 1-2 million times. The keyboard symbol printed on UV inks appeared to have worn about 13 million times. The abrasion resistance of UV inks is 1300% of the wear resistance of traditional inks. Not only that, but also the objective drying speed is greatly improved compared to traditional inks, from the original 7 minutes to 15 seconds, saving 96%. time.
UV inks also have extremely high solvent resistance after drying. This solvent resistance results in part from the high crosslink density (macromolecule weight) of the crosslinked dry ink layer. A higher degree of cross-linking allows the use of solvents in conjunction with some solvent-resistant chemicals.
For the purpose of comparison, we have changed the situation of epoxy inks into UV inks. First, do not mix the ink before use. Second, of course, it is time-saving because the epoxy-based ink needs to be dried for a long time under a certain high temperature condition, and the UV ink is almost instantaneously dried. This is accompanied by the additional advantage of reducing the damage of the ink layer caused by heating. UV inks also save a lot of drying workshops.
There is also a drawback to the formulated epoxy ink. Its stability is poor. After mixing for a while, it will condense in the ink fountain. You must stop and wash the ink fountain. This leads to a waste of time and a drop in productivity. However, UV inks are different, and its stability is very good. It can be said that condensation does not occur. More features and comparisons of UV inks and traditional inks are also listed.
Of course, there are specific factors to consider before converting the ink used. Such as the need to switch to UV ink equipment capital issues, measuring instrument problems. If the surface energy of the surface of the substrate is low, the surface must also be subjected to photochemical treatment to ensure the adsorption of the ink, which requires additional new quality control equipment. It is recommended that you do a good overall planning before the conversion and do not rush.
Source: Advertising Industry Channel
- This bread Dough Scraper has a super sharp stainless steel blade to cut bread perfectly.The material of Pastry Blender also is stainless steel,They are nonstick, anti-rust, and non-toxic,safe for everyone!The weight of pastry blender is 3.2 ounces and dough scraper is 6.4 ounces.
- EFFORTLESS TO USE AND CLEAN - The handle is made of TPR and PP, turning it wide, comfortable, and non-slip for ultimate control! Simply use a dishwasher to clean it.
- SMART DESIGN- Both tools have a soft non slip rubber handle for easy gripping and is made of quality stainless steel.The shape of the handles are ergonmically designed to reduce the stress on your hands.The measurement scale of dough scraper male cooking easier .
- MULTIFUNCTION - Blade has a sharp beveled edge for easy chopping and scraping Can be used to cut vegetables, dough or smooth cake icing as well as lift and turn cookies and pastries off a cookie sheet and is a perfect compliment to the included pastry blender. Can also be used on a griddle or grill to scrape away food residue or cut and mix grilling foods such as bacon.
- GET YOURS NOW! - Our Pastry Blender is a compact tool (4 x 2.7 x4.7 inches)and the size of Dough Scraper is 6.3 x 4.7 inch , so it doesn`t take up much space in your drawer. Place your order now before we run out of stock.
Professional Blender,Dough Scraper,Stainless Steel Scraper,Stainless Steel Blender
Yangjiang Homelife Industry & Trading Co., Ltd. , http://www.bettyhomelife.com