Application of Non-absorbing UV Printing Ink on PVC Static Film (I)

INTRODUCTION: After more than 10 years of exploration on non-absorbing light-curing printing inks, this paper believes that an effective way to resolve adhesion, increase flow, prevent photon decomposition, reduce ink costs, and improve ink properties is to add IJJ to its system. TM additives. In this regard, the author's little bit of practice is discussed with people both inside and outside the industry.

1 The Prospect of UV Ink

UV inks are broadly referred to as lithographic, flexographic, gravure, screen printing, and other printing inks that are cured with ultraviolet light. In the past 30 years, people have been working hard, improving, and experimenting. As a new edge discipline in green packaging and printing inks, it has become a new international fashion because of its small pollution, fast drying, and low energy consumption. "A fresh air and a clean and pleasant land" have already become the voice of people in the packaging and printing industry. But really high-speed, full-automated, photo-realistic offset printing, especially UV inks on non-absorbing non-polar materials are rare. The reasons are: the cost is too high, the adhesion is poor, the low temperature does not flow (usually by heating), the film formation process, and even after the film formation photon may be decomposed (free radicals) and so on and is limited by the scope of application. Followed by the film crisp, in the PVC electrostatic film on the screen easily lost or friction toner off has become a major difficulty, rely on UV Varnish to make up for their defects are often wasted time and affect the improvement of the authentic rate. The breakthrough in UV-curable offset printing on non-absorbing electrostatic film materials has been the development of the product.

2 Exploration of Theory and Practice

It is well known that UV-curable inks can be used, which are abbreviated as UV inks. It is composed of a photopolymerizable oligomer, a diluting monomer and the like (resin binder) and then added with a photoinitiator, a colorant and the like. The linking materials are broadly classified into three major types-(1) active group polymerization type, (2) active group addition polymerization type of polyenethiol curing system, and (3) ionomer type 3 of epoxy resin.

The arrival of market internationalization and economic integration will surely be influenced by ecological policies. UV inks also face fundamental breakthroughs in scientific theory and innovations in application technology - it is no longer just paper, paper boxes, packaging papers, labels, metal foil composite paper, ink or water based on non-ferrous metals, directly on molecules or ions. Or indirect use of lithography, flexo, screen, gravure, transfer printing, and even computer-assisted printing or non-absorbing printing media. With the aspiration of non-absorbing non-polar plastic materials in packaging, UV inks cannot cope with this market space.

In order to improve the packaging printing environment, the equipment for photo-curing ink and photo-curing varnish is 15KM-64KM; in order to ensure the balance of drying speed in printing graphics, people always rely on different pigment wavelengths in the color ink system. Arrange printing color sequence: white ink - black ink - cyan ink - yellow ink - red ink; and according to the number of color hue to install or open the UV lamp (bubble) and adjust the light receiving distance, in order to completely guarantee the product The high quality, and prevent the ink film from falling off, the printer is now more than offset with a UV coating.

Looking at the UV ink and UV coating on the market, the principle of drying is nothing more than photochemical reaction. The first condition is that the molecule must have enough energy photons to become excited (state) molecules. Just as every photon known to people can only activate one molecule; the same molecule can only absorb one photon at the same instant. Therefore, the theory is often interpreted as follows: After a molecule absorbs a photon, an electron transition to a higher-level energy position occurs. The molecule that undergoes an electronic transition is called an excited state (ie, a molecule). This excited state molecule returns after releasing energy. In addition to the ground state, it is also possible to transfer energy to other molecules or to generate free radicals. After the energy conversion of the photosensitive polymer to the curing of the polymerization is photocrosslinking and photobridges. Whether the ink system contains a photoinitiator, the purpose thereof is to cause a photocuring reaction of the UV ink system, that is, a result of a photochemically induced chemical reaction, or a UV ink and a UV coating containing no initiator that have been introduced in recent years. Its photocuring is the result of the chemical reaction of photopolymerization after the solvent crosslinks the system into a network structure. The system contains ultraviolet absorbers. In absorbing natural sunlight and fluorescent sources, ultraviolet rays can be converted into hardened crosslinked ink films. structure.

We rigorously categorized and screened UV inks of the same application and thought that iodine lamps as black light sources and cold light sources of cold light sources were recorded during the ink drying process. In terms of safety, the former was superior to the latter because When the UV non-absorbing offset is printed on the pressed ink film material and exposed to ultraviolet or visible light, the electrons in the outer layer of the molecule are excited to jump to a higher energy level (bit) before light absorption occurs. The author applied different adjuvants and the same colorant to test the unsaturation of Wuhan resin, Xi'an resin and commercially available 191, 196 resin, and compared the detection - different bonding in the molecule (including different Qualitative and quantitative analysis of organic compounds and metal complexes of saturated bonds, aromatic rings, and heteroelements. Although the UV region is between 200-400 nm and the visible region is between 400-800 nm, it only accounts for 4% of visible light. It is this 4% effect that produces the photochemical reaction. Of course, we understand that the absorption of light of different intensities tends to occur at different wavelengths, and the absorption spectrum formed by it has a high sensitivity (photochemical reaction) and is almost invisible. Fast drying with compound curing, better design of complete automation (from offset printing to curing), and adaptability to trace, trace analysis and kinetic studies - from light source to light intensity (voltage will not be the same) From lamp type to output pitch (distributed spectral distribution is also different); from ink film thickness (including the amount of photosensitizer in the system) to ink pigment The length of the film (the more transparent and thinner the ink film, the shorter the wavelength, the greater the energy of the light, and the faster drying); The large amount of surface tension, hydrogen bonding force, and free energy of the substrate are used to test the adhesion. Test and analysis.

In addition to the above-mentioned theoretical literature that the molecules are excited outside the high-energy sites, it is also possible that under the action of photosensitizers or UV absorbers, photon decomposition (both photodecomposition processes), or activation of a part of the bonds, will be activated. Molecules (radicals), which cause double-strength polymerization reactions or cause photo-crosslinking reactions such as coupling bridging, have been agreed by the ink industry. However, the use of non-absorptive polar UV inks may again cause photon decomposition - this is not repeated here.

In addition, we use the properties and properties of UV inks to use high-speed offset non-polar materials, and we have found time-consuming and laborious searches in existing literature, arguments, data, and sources to conclude that ink materials are mostly written and translated by outsiders from the actual There is still some use. To this end, after calling the former Shanghai Ink Factory Chief Engineer Mr. Haiyan Yang, known as the “Star of the Ink” who was awarded as one of the four-year ink printing veterans of the Fourth Printing Award, he came from Anhui, Jiangsu, Guangdong, Zhejiang, Hunan and Shandong. The three-month field visits, demonstrations, development, and application of the heavy trust of manufacturers in Hubei and other places have received great results. In accordance with the national standards of QB/T3597-1999, there is a goal to build their own brand and compete with "wolf" and dance with "wolf".

To achieve UV offset non-polar materials, to achieve adhesion fastness, change the low temperature characteristics, can flow normally and do not need to rely on the passive operation method of glazing oil. After researching the above issues, the author found that most ink and non-polar printing The hydrogen bond value, PH value, free energy value, and surface tension value of the material are too wide to change the overall structure of the existing UV ink UV varnish. At Jiangsu Yizheng Tianyang Chemical Plant, Tianjin Lisheng Chemical Factory, Songzi With the support of the resin plant and other units, boldly adopting grafting, compounding (mixing) technology, using “value engineering”, “orthogonality”, and “backward algorithm”, adding 0.25 with the support of Mr. Li Xiang of Qingdao. % Commercially available LJJ·TM additive, introduced into the UV ink system, after being simply dispersed, cooperated with Qingdao China Daosheng Printing Company. After the start of printing, it can be adhered to a solid and gratifying effect after it is no longer glazing - fewer materials, simplification of the process, shortened cycles, increased suitability, and improved quality. We have learned from this that only by occupying the high ground of science and technology can we expand the printing and consumption space of non-polar flexible packaging printing media; only when occupying the beachhead of the market economy can we repeatedly emphasize that time is money and quality is life; only high quality and low price Based on printing inks, we can seize the opportunity to occupy the beachhead of the market economy; only if we have no people, we have excellent people, and we have new people, can we capture domestic and foreign counterparts in the network economy from the market information feedback. The latest scientific and technological achievements are for my own use. On the contrary, they are all "on paper".

3 Innovation and Improvement Ideas

Green non-absorbing UV offset polar material inks, as the name implies, are composed of different inks, and require adhesion, high flowability, low cost, simple process, bright colors and no need to polish.

We analyze the "ink manufacturing process" textbook "Example Formulation Design: 1 Polyol 25-45; 2 Polyol 20-40; 3 Acrylic 10-30; 4 Hydroquinone 0.05-0.2; 5 Pairs Toluene sulfonic acid 0.1-2, binder material) Enumerated ink formulations (1 colorant white 50-60%, color ink 15-25%; 2 binder material 40-70%; 3 adjuvant 0.01-20 %) to detect and analyze, it is not difficult to see that with the changes of the times, the acid mixture of the system is the main cause of the photon decomposition process (molecular decomposition) under the action of the photoinitiator caused by the UV ink film formation process or film formation. One of the hands, in addition, we according to the current resin technical indicators, 1 viscosity 25-50 Pa · sec / 25 degrees Celsius; 2 acid value of 20 or less; 3 color <10; ink technical indicators, 1 color near sample, 2 fineness 15- 20um, 3 fluidity 20-35um, 4 coloring power 90-110%, 5 viscosity 15-25 (32 degrees Celsius), 6 impact strength, (N·m) 29.4, 7 light setting time, S1-3, etc. After earnest and repeated research, it was discovered that the position of fluidity has not been adapted to modern high-speed web offsets. Requirements of the carrier. For example, we have increased the styrene, which is an alkaline solvent, to improve its fluidity. However, after ultraviolet light curing, especially after the back exposure, the gloss is slightly poorer, and the second is that the friction ink film falls off into particles. The resin composition in the ink film system is small and overly brittle. From a large scale, the acid ink will improve the fastness of the printing ink film. However, with the above-mentioned failures, we felt helpless at the moment and interrupted several years of research. In order to break through the existing academic theories and set aside a dead end of the environment and conditions - if traditional light-curing inks do not damage the PS printing plate, and the transfer roller of the printing machinery, they ignore the practice of bypassing this restricted area. Go effortlessly to capture the latest, most up-to-date and optimal new materials and take the initiative to cooperate with relevant research institutes and related industries to conduct targeted research. From the point of view of the unsaturated resin (general term for a resin material obtained by the condensation of a monohydric or polyhydric alcohol and a dibasic or polybasic acid), we have set the following formulas and processes for resin binder, color, and dye coloring (see table). In the fashionable "take-up" doctrine, it is to abandon the traditional practical loading method. We use compounding technology to add additives. In the formulation, we have designed the colorants - inorganic pigments, organic pigments, extender pigments, metal powder fluorescent dyes, etc., also from the price, color, light and dark, alkali resistance , Wear resistance, especially ink curing characteristics, storage stability, surface reflectivity and wettability considerations.

1. Wuhan resin manufacturing process material link

Put the fat into the reactor first, when it is heated to 120-130°C, stop the heating. When it is reduced to 120°C, put the photoinitiator into homogenizer, wait until it drops to 100°C, and add sensitizer and colorant. Continue When the temperature is lowered to 60°C, the auxiliary resin, hardener, and plasticizer prepared in advance are mixed and put into a kettle, and uniformly dispersed or rolled until the fineness is acceptable and the UV-curable printing ink is formed.