At present, there are 4 types of inks that can be used as heat shrinkable materials: cationic UV ink, free radical UV ink, solvent-based ink and water-based ink. Let's take a look! 1. Cationic UV ink Cationic UV ink is used less in the field of heat shrinkable film printing, mainly because its price is too high, it is necessary to use a specific device, by using a photoinitiator to produce acidic substances under UV lamp irradiation to catalyze the polymerization reaction. The cationic agent induces a chain reaction of the epoxy group until the oxygen bond is broken or a glassy polymer is formed, and the chain reaction is terminated. The infrared light emitted by the UV lamp is the key to controlling the reaction speed and the complete reaction. The cationic polycondensation reaction must fully understand the properties of the film, to avoid ink cracking, and to ensure that the ink is completely cured. ? Cation ink advantages The reaction type is a typical epoxy group step-by-step ring-opening polymerization reaction, which increases the content of the ink's active ingredients, and is almost completely converted into an ink film. ? Cationic ink shortcomings Longer reaction time Since the cationic polycondensation reaction is slower than free radical polycondensation, it takes a longer time for the ink film to crosslink and attach to the substrate to reduce the pressure on the substrate. The shrinkage of the ink film of the cationic cured product is generally less than 5%. Because the reaction rate is slower than free radical polymerization, high temperature curing is often required High temperature curing and low ink film rate shrinkage will often result in uneven and uneven edges of the ink film. In general, choose a UV light source of more than 80W to ensure the rapid and complete curing of cationic ink. If it is below this temperature, the durability and adhesion of the ink film will be significantly reduced, and the smell will be large. The cationic polycondensation reaction will be terminated by the influence of atmospheric humidity High humidity weather will cause constant changes in ink properties. Therefore, the temperature and humidity control system is a necessary device for cationic UV printing. Ink composition selection is difficult First of all, the price of basic components of cationic ink itself is higher than that of free radicals. Secondly, since alkaline substances will delay or even inhibit the progress of the reaction, the content of such substances in the ink cannot be too high. Acidic substances can not be used in excess too, otherwise it will increase the viscosity of the ink into a gel. To this end, ink engineers must strictly control the type of pigment in the ink composition, surface treatment of the pigment to make its pH value neutral. Therefore, there are many pigments that cannot be used because they cannot meet the requirements of UV ink fluidity and viscosity. High requirements for dispersants Cationic inks have strict regulations on the type of dispersant, which in turn limits the amount of pigments added to the ink, resulting in poor color expression of the printed ink layer and infrequent graphic colors. Cationic initiators contain heavy metal elements and also generate small amounts of benzene, which not only pollutes the environment, but also endangers the health of workers. 2. Free radical UV ink The free radical UV ink device also uses UV light to irradiate the photoinitiator to induce the chain polycondensation reaction of acrylate until the free radical reacts with pigment, oxygen, additives or other free radicals, or vitrifies to terminate the chain reaction. In general, there will be a small number of secondary splits after the ink is cured under UV light irradiation, but in fact there are few real post-curing processes. Therefore, when the ink cools and adheres to the substrate, there will be adhesion, scratches and other phenomena. The infrared light emitted by the UV lamp can accelerate the curing speed. This radical reaction is slightly worse than the cationic reaction, but there are still other methods to obtain the ideal curing effect. ? Free radical ink advantages Fast response The curing of free radical ink does not require too high temperature, and it can be cured quickly under a low-energy light source, which greatly reduces the heating of the substrate and avoids the shrinkage of the heat shrinkable film during printing. And its requirements for ink are not as harsh as cationic ink. In this way, various pigment choices are enough to ensure good rheology of the ink on the YAG anilox roller. In addition, high pigment filling reduces the volatile components of the ink, reducing shrinkage and odor. Wide printability Since the radical ink has no excessive restrictions on the selection of ingredients, it can print substrates with strong alkalinity and joint printing with alkali-soluble and water-soluble flexographic printing inks. Fast drying The high adhesion allows the free radical ink to instantly adhere to the substrate and cure rapidly under the irradiation of a low-energy light source. In this process, the printing material is not heated, but the cationic ink cannot print at high speed due to the high curing energy requirements. This just solves the problem that UV flexo printing productivity is lower than gravure printing. With proper curing device and pressure setting, free radical ink will break out of this bottleneck. The new free radical UV technology can achieve no heavy metal elements and no benzene generation, but the printing speed is slightly reduced. ? Free radical ink shortcomings Free radical ink reacts quickly and can quickly cure all the components together, which will increase the pressure on the substrate. When printing a heat shrinkable film, excessive pressure and a small amount of heat from the UV lamp will cause the film to shrink and deform. The shrinkage will also make the free radical UV ink as flexible as other UV inks, and the affinity and adhesion will be poor. Free radical ink is easily oxidized. This can be solved by using high-energy light sources, high-efficiency ingredients, or using oxygen-absorbing initiators (such as diamines and triamines). It should be noted that this is an experimental result obtained under relatively stable air conditions without too many fluctuations. If it is used in actual production, further demonstration is required. At present, some companies, such as Flexocure XS UV radical polymerization flexo ink introduced by XSYS, have shown that it can achieve a shrinkage of 70%, and the product also has good adhesion, and a wide range of applicable materials, such as PVC, OPS, OPP, PETG, etc. Even under the condition of shrinkage rate of 70%, these new technologies of free radical polymerized flexographic printing ink can show good abrasion resistance, without the need to use primer and varnish. These products have the advantages of high color strength, fast curing speed, excellent printability and printed product performance. It can realize two processes of surface printing and internal printing. At the same time, its excellent curing performance and low viscosity are effective guarantees for production capacity. 3. Solvent ink Solvent-based inks are generally used in gravure printing and consist of pigments, solid resins, volatile solvents, fillers and additives. The pigment components of gravure inks are mostly organic pigments. Organic pigments contain metal elements such as lead, chromium, mercury, copper, etc., and have certain toxicity. Solvent-based inks are the largest source of pollution in the printing industry. In 2004, the annual output of world inks was approximately 3.5 million tons, solvent-based inks accounted for an average of 30% to 40%, and the amount of organic solvents brought by inks worldwide was as high as 1 million per year Tons. In addition, the ink also contains heavy metal elements that are more harmful to the human body. The binder contains 40% to 50% of organic solvents, and long-term contact will damage the human skin. The organic solvent content in the air is high, and passive inhalation can cause damage to the respiratory system. In addition, more organic solvents are used in the ink, and it will also react chemically with some gases in the air, producing stinky chlorine and smog, which seriously pollutes the air, has a greater impact on the growth of various plants, and destroys the ecological balance. Therefore, the traditional gravure solvent-based ink tends to be eliminated. Replaced by alcohol-soluble composite plastic inks, benzene-free solvent inks and water-based inks. Since water-based gravure inks cannot fully replace toluene inks, the ink industry has been working hard to develop alcohol-soluble inks that are environmentally acceptable. Alcohol-soluble ink can effectively solve the health problems caused by toluene-based ink and the residual solvent affects the quality of packaged food. In Europe and the United States, this development has become a trend. In Asia, such as Singapore and South Korea, toluene inks are being eliminated and will be replaced by alcohol-soluble gravure inks. Alcohol-soluble inks have been widely used in the domestic gravure industry. It is foreseeable that alcohol-soluble inks will occupy a certain share of the shrinking label ink market in China in the near future. 4. Water-based ink Water-based inks are generally used in flexographic printing. The fundamental difference between water-based inks and solvent-based inks is that the solvent used in water-based inks is water instead of organic solvents, which significantly reduces VOC emissions, can prevent atmospheric pollution, does not affect human health, is not easy to burn, stable ink, bright colors, not Corrosion plate, simple operation, cheap price, good adhesion after printing, strong water resistance, rapid drying, so it is especially suitable for packaging printing products such as food, beverages, medicines, etc. It is the world's recognized environmentally friendly printing material, and it is also all printing inks The only ink approved by the American Food and Drug Association. At present, 40% of shrink film production in the United States uses water-based inks, and other economically developed countries (such as Japan, Germany, France, etc.) use more and more water-based inks in film printing. According to relevant reports, in the United States, the composition of water-based inks that meet the VOC emission regulations must reach the state of use, the proportion of volatile components is less than 25%, and the moisture is more than 75%; inks with low moisture are not volatile in use. The two standards with ingredients above 60%. At present, water-based inks in gravure printing have also made considerable progress. The WE-type plastic film gravure water-based ink produced by Beijing Yingkefan Chemical Products Co., Ltd. uses water as the main solvent, a variety of high-molecular polymers as the film-forming substance, and is equipped with advanced organic pigments, inorganic pigments and various additives. In line with environmental protection requirements, it has good printing performance and adhesion fastness on BOPP, PE, PET and other plastic films with a surface tension of (3.6 ～ 4.2) × 10-2N / m. After the color printing and packaging factory actually printed on the BOPP film at a speed of 70 meters per minute, it showed that its printing effect and performance can reach the level of similar products with aromatic hydrocarbon as the main solvent. Editor in charge: null Functions of eye black Mascara,Waterproof Mascara,Eyelash Extension Mascara,Natural Organic Enhance Lash Mascara Suzhou Yimeijia368 Biological Technology Co.,Ltd. , https://www.ymjbeauty.com
1. It has the effect of lengthening eyelashes and enlarging eyes.
2. It can bring curling and supporting force to eyelashes.
3. It can improve the support of eyelashes, and the shape of eyelashes is curved. Especially when we blink and close our eyes, these two layers of eyelashes like small fans can prevent the upper eyeliner from contacting the oil of the lower eyelid and faint, so it is necessary to curl the eyelashes before brushing them.
Misuse of eye black
1. Apply eye black more than 3 times. It is enough to apply eye black twice. If you don't want your eyelashes to form a ball, generally speaking, you can get the best effect by applying it twice.
2. Insert and pull the eyelash brush. It is easy to harden mascara, because air is mixed in the process. Eyelashes are easy to coalesce, and the floating powder is serious.
3. Start applying eye black from the middle of your lashes. When you apply eye black, you must start from the root. eye black is not used for a long time, and it will dissolve when you apply it, so the application method is likely to be wrong. The possibility is as high as 99%. Generally, the curly eye black with larger mascara brush is used.
4. At first, eye black was too thick. Sweep up gently, and then emphasize the wavy feeling when smearing according to personal conditions. Too much mascara at a time is easy to get dirty, because the eyelash state has not been adjusted to the best.