Crosslinking agent for the hottest low viscosity p

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Crosslinker of low viscosity printing inks

printing inks are often divided into paste inks with high viscosity and liquid inks with very low viscosity according to their viscosity value. The most common paste inks are offset printing inks and silk printing inks. The viscosity of gravure ink, flexo ink and ink is very low, so these printing inks are also called liquid inks

in the drying method of low viscosity ink (liquid ink), drying ink through crosslinking reaction is a drying method of ink. At present, UV curing ink and EB curing ink (electron beam curing), which are used more and more in the printing industry, belong to the category of crosslinking reaction fixation

among the components of crosslinking reaction fixing ink, the crosslinking agent in the binder is one of the key components. The choice of crosslinking agent affects the drying speed of ink film after ink printing; In addition, the crosslinking agent will also affect the viscosity of the ink system itself and the adhesion of the ink on the substrate surface after printing; Third, the crosslinking agent will also affect the various resistance of the ink film on the printing surface, such as the heat resistance, light resistance, water resistance and solvent resistance of the printing surface

to sum up, crosslinking agent is an important component in the formula of printing ink and glazing oil, which is used to improve the performance of ink and improve the printability of ink. When selecting the crosslinking agent of ink and glazing oil, it must be carefully selected to give the ink or glazing coating distinctive characteristics

next, let's briefly introduce some crosslinking agents used more in the ink system and glazing oil: crosslinking agents of oxidation system: trace back to the crosslinking agents used in printing ink. Unsaturated oil substances may be regarded as the elders in the ink system. Unsaturated oil substances undergo crosslinking reaction through oxygen gas, so as to achieve the drying and fixation of ink or glazing oil. Oxidative crosslinkers are usually used in sheet fed offset printing inks and grease based inks, but not much in liquid inks. However, oxidation crosslinking agent can also be used in liquid ink, and can give ink unique performance. Good alkali resistance is the most prominent advantage of this crosslinking agent. This advantage is very useful in some printing. For example, the packaging printing paper of soap needs a strong alkali resistance on the surface of the printed matter. At this time, the oxidation crosslinking agent can play a role. Oxidizable alkyd and epoxy resin can meet some special applications in some printing. The oxidation crosslinking agent can be used with or without catalyst to promote oxidation reaction. Oxidation crosslinking agent can give ink products superior adhesion and resistance

zinc ammonium carbonate and zirconium ammonium carbonate: inorganic crosslinkers such as zinc ammonium carbonate and zirconium ammonium carbonate react with resins and carboxyl groups to produce zinc ion bonds or zirconium ion bonds, which have strong heat resistance and alcohol resistance. Zinc ammonium carbonate and zirconium ammonium carbonate are commonly used in water-based inks. The pH value of ink formulation system is usually 9 or higher. If the pH value is lower than 9, the chemical properties of the ink system will become unstable

silane: silane is a promoter to improve ink viscosity, more specifically alkoxysilane. Silanes can be added to solvent based inks or water-based inks, which can react with the carboxyl group of the resin. The chemical reaction will take a little longer. In addition, the ink added with silane needs a higher drying temperature after printing. Silane has good viscosity and resistance, which are well reflected in ink products

organic titanate and organic zirconate: organic titanate and organic zirconate are another crosslinking agent of the ink system. Many common ink resins often use organic titanates and organic zirconates as ink viscosity accelerators, such as nitrocellulose resins and polyurethane resins, which use organic titanates and organic zirconates to improve ink adhesion. The chemical properties of organic titanate and organic zirconate are very active, so they should be carefully prepared in the ink formula to ensure the stability of the ink system. Organic titanates and organic zirconates have been used in solvent based inks for many years. Now, the body rotation of organic titanates can also be seen in some water-based acrylic ink formulations, and the continuous increase of automobile production

photoinitiators: photoinitiators used in UV inks and UV varnishes are special crosslinkers. The curing principle of UV ink and UV varnish is: first, photoinitiator (crosslinker) absorbs the ultraviolet light emitted by UV light device to generate reactive radical, which can polymerize and crosslink UV monomer to form polymer film. After the ink dries, the ink film gives the printing a step further to strengthen the research and development of new materials, and the brush has good gloss and resistance. At present, there are mainly two types of photoinitiators in UV inks and UV Varnishes: free radical photoinitiators and cationic photoinitiators, which have been used in some UV curing ink systems for many years. As the photoinitiator determines the drying speed of UV ink or varnish, the selection of photoinitiator is a key link in the formulation of UV ink or varnish

the above mentioned crosslinking agents have their own advantages and disadvantages. No crosslinking agent is perfect. Crosslinking agent also needs to be used with other additives to make the ink meet the printing requirements. Because many crosslinking agents are toxic and smelly, they obviously cannot be used in the packaging and printing of food and drugs. Therefore, it is very important to carefully and scientifically select the ink crosslinking agent to meet the requirements of printing customers. 3. Display method: LCD is necessary

source: Yin Guang

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