R&D Of Environment Friendly Soya Ink

In general, there is 30%-60% mineral oil in traditional ink. In the process of printing, ink could dry thoroughly through volatilizing the mineral oil, while a great of organic solvent is let off to the atmosphere to cause pollution. Every year VOC(VOLITILE ORGANIC CHEMICALS)from ink has been reached hundred thousand tons, which can form greenhouse effect worse than one caused by CO2, and pollute atmosphere seriously by the way that oxide and photochemistry fog can be formed in the sunshine. For printing worker, it will do harmful to human body, especially to nerve system, since people is working in so high concentration of VOC. Therefore, how to lessen concentration of VOC in ink has been very important point in environment management for very country. Today, many countries have begun to enact law and regulation to limit the use and let off of organic solvent.Soya ink make the ink have less VOC because it use natural and environment friendly soy oil to substitute 20%-50% mineral oil in ink, which can reduce VOC of the traditional ink from 30%~60% to 5%~15%, as a result soya ink will be used widely, and become the important role in offset and web ink under the drive of environment protection.Although the soya ink has a wonderful future, there are some difficult in developing soya ink because soy oil has some inherent faults in drying. The main difficult points are listed as following: (1) to adjust the drying of soya ink to normal;(2)to adjust the various properties of soya ink to close or supreme the traditional ink. Soy oil has only 9% flax acid, which has rich double bond, and nearly 80% stearic acid, oleic acid and flax oil acid, which is lack of double bond. By comparing, traditional ink has more than 52% flax acid, while the thing with few double bond is just 30%. Therefore, soy ink has few double bond that can react with oxygen in atmosphere, it is classified as semidrying oil. As a result, the soya ink make from soy oil can not get a hard film of ink from bad drying, andcause the soya ink to low its' printability, and some other pinting problem such as offsetting, bad adhesive and so on. The substitution break through the balance of properties of traditional ink, which need new ink design to balance the properties of soya ink again to get good performance of soya ink.For ink, factors to drying are not only vegetable oil, but also resin, mineral oil and manufacture method of vanish. Although soy oil has fault in drying, the problem can be solved by the way of selecting fit resin, designing vanish, and selecting manufacture method of vanish.. According to the view point above, this paper focuses on the selection of resin, design of vanish, selecting the manufacture method of varnish and design the ink to study, there are the content and result as following:1) The type of resin and mineral oil is selected regarding to the demand of environment protection and property parameters of the resin and mineral oil. At last three types of resin and one type of solvent is selected. Resin 1: solubility parameter 1.0, sotening point 180°C, molecular weight Mw 20000, acid number 17. Resin 2: solubility parameter 0.9 > softening point 180 "C > molecular weight Mw 27000> acid number 19;Mineral oil: distillate range 280°C~310°C, aniline point 93.5°C, freezing point -12°C, benzene hydrocarbon content <0.5%o2) Designing the experiment through perpendicular experiment table, prescription of vanish and manufacture method are selected. By comparison of set speed, rheology, viscosity and solvent tolerance of vanish, ascertain one soft and one hard vanish. Soft varnish: viscosity 54800, solubility parameter 1.0, set time <8 minutes, finger feeling is soft and smooth, hard varnish: viscosity 66300^ solubility parameter 0.9, set time <8 minutes-> finger feeling is hard and smootho3) By the way of dryer experiment, the volume of dryer to every kind of vanish is ascertained. The result is that addition of 0.15%Co type dryer and 0.45% Mn type of dryer to ink can get a good drying.4) By the way of adjusting the proportion of ingredients of ink, the fit prescription of ink is ascertained. At last, magenta, yellow, cyan and black four color process ink isascertained, the performance has been close even suppress the same type traditional ink.Therefore, the developed soya ink can substitute for traditional ink better by a series works such as selection of raw material and adjustment of manufacture method.