Suitability of the most environmentally friendly s

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Soybean ink has the advantages of printing quality and environmental protection. It has been applied to sheet type, rotary type, commercial form, elastic relief ink and so on. In this study, the suitability of soybean ink for lithography such as viscosity, stability of anti splitting force, Emulsification Characteristics and particle size was tested, and the concentration and gloss were measured after the paper was developed. Then, it was analyzed and compared with the general traditional ink to understand the difference between soybean ink and the general traditional ink in the suitability of lithography

1. Introduction

1. Research motivation and background

the composition of general lithographic inks includes colorants, media and some additives, among which the media are mainly hard resin, vegetable oil and some non plant ingredients. The vegetable oil in soybean ink is the composition of some soybean oil. The composition of soybean oil varies with the printing method. It is not the same as that of petroleum based ink. Although soybean ink contains the same pigments as petroleum based ink, most of the pigments are petrochemical products. However, soybean ink can be partially decomposed, while petroleum based ink cannot

as for the production of soybean ink, the americannewspaperpublisherassociation (ANPA) advocated the development of alternative petroleum based printing ink in 1979. At that time, it coincided with the second oil crisis. The export of crude oil by the crude oil export organization (OPEC) indirectly affected the supply of raw materials. In order to reduce the dependence on foreign imported crude oil, vegetable oil with both non-volatile and decomposable properties was found, It can produce vegetable ink instead of petroleum based ink, which can improve the abrasion resistance of newspapers. In addition, volatileorganiccompounds (VOCs) in petroleum based inks caused ecological harm. Later, after testing more than 2000 kinds of vegetable oils, scholars believed that soybean inks containing soybean oil were non-toxic and usable. Therefore, in 1987, American sunshine chemical company began to produce soybean inks, which were later introduced to the newspaper industry for use. At present, soybean ink has even been popularized all over the world. Later, there was a soybean seal marking the ink containing soybean oil. Taiwan is also promoting its use in the printing industry (wangshouhong, 2004; irot, 2004; mear, 2004; Patterson, 2003)

in terms of the printability of soybean ink, it has the following characteristics:

(I) the emulsifying ability of the ink is weak, and it can maintain its rheological properties and watertolerance in more than 50000 printing.

(II) when adding the same amount of water, the reaction of soybean ink to water is significantly sharper than that of mineral ink, and the ink transfer recovery is cleaner and faster, And soybean ink has relatively low anti splitting power

(III) in terms of ink viscosity, borisfuchs et al. (1991) showed that concentrated soybean ink has relatively low viscosity, but irot (2004) mentioned that the viscosity of soybean oil is much higher than that of mineral oil at 23 ℃

soybean ink has the following advantages in the application of printing:

(I) it has good abrasion resistance, so that readers will not be troubled by black hands

(II) no irritating odor

(III) the ink is thick and bright, so that the printing industry can use less ink, save costs and increase printing units

(IV) can reduce the point expansion

(V) in terms of environmental protection, the VOCs contained in soybean ink is 17% of petroleum based ink, which can be said to be non-toxic ink (mear, 2004)

(VI) it has good deinking performance, and can be backfilled and recycled in black ink mixing, which is conducive to environmental protection and low cost (mpson, 1994)

as for the disadvantages, the only soybean ink with a higher price than petroleum based ink is the black ink used for newspaper printing, which is about 25% more expensive, and the soybean ink dries more slowly than mineral ink (irot, 2004). The application of soybean ink in lithography still faces some problems. For example, the surface of printed products is prone to be stained due to incomplete drying of the ink, and there are large differences between the hue and the final version, poor color gloss, insufficient picture performance levels, and no three-dimensional sense. In addition, it is also found that there are problems of insufficient black ink concentration and poor balance between yellow ink and ink (lvlihua, 2004)

based on the above characteristics and problems of soybean ink, this study intends to conduct an experimental analysis on the printability of soybean ink in lithography, compare the differences in printability between automatic soybean ink and general lithographic ink, and discuss the characteristics of soybean ink in lithography

II. Research purpose

this study tested a group of four colors of green, magenta, yellow and black lithographic soybean inks with a group of four colors of general lithographic inks, in order to explore the differences in printability between soybean inks and general inks, and provide the results for the printing industry as a reference

the purposes of this study include:

(I) to explore the differences in lithography suitability between soybean ink and traditional general ink, including the differences in anti splitting stability, viscosity, emulsification rate and particle size of ink

(2) to explore the differences in the concentration, hue and gloss of soybean ink and traditional ink in paper color development

(III) from the stability of anti splitting power of soybean ink, the regression curve equation of the stability trend of anti splitting power of soybean ink was calculated

III. research process

the purpose of this study is to explore the difference between soybean ink and general ink in lithographic printing suitability. Therefore, a group of soybean ink is used as the experimental group and a group of general ink as the control group to compare and analyze the printing suitability of soybean ink

II. Literature discussion

I. vegetable inks

in addition to traditional inks, many environmental friendly inks have been developed. In order to meet the requirements of environmental protection, we should first change the ink composition, that is, use environmental friendly materials to prepare new ink. At present, 300 joints of the same type are one batch of the main environmental friendly inks; There are mainly three types of water-basedink, uvink and vegetableoil basedink under field installation conditions

(I) evolution

in the 1980s, the American Publishing Association (no oil flowed out of the oil delivery valve return pipe ANPA) developed a series of ink blending, which mixed hard asphalt and talloilfattyacid with carbon black pigments. However, these inks were limited by the price and availability of tall oil, and the asphalt was difficult to clean, so they were not fully accepted by the industry. Later, ANPA improved and developed a kind of media (vehicles) suitable for lithographic printing ink in 1985, including alkaline refined soybean oil, hydrocarbon resin and pigment (wangshouhong, 2004; noirot, 2004; axmear, 2004; Patterson, 2003)

(II) structure there are three basic types of vegetable oil in vegetable ink:

1 Dry oil: in the printing process, when the oil is in contact with oxygen, the new dominant state of Shandong raw material industry will be transformed from liquid to solid, where the oxygen controls the role of the catalyst. In the past, the printing ink industry mainly used dry oil. The medium in the traditional ink usually contains linseed oil or other dry oil, and also contains some petroleum substances as the solvent in the medium

2 Semi dry oil: Vegetable ink usually uses semi dry oil such as soybean oil, corn oil, rape seed oil and tall oil to replace the petroleum substances in the ink formulation

3. Non dry oil: from the molecular structure of inks, vegetable oil molecules are very different from mineral oil molecules. Mineral oil molecules are three to five times smaller than vegetable oil molecules without considering branching. Due to the difference of molecular structure, vegetable oil is much heavier than mineral oil, so vegetable oil can hardly be fixed and dried under heating (noirot, 2004)

(III) characteristics

1 Viscosity

the viscosity of the oil used in traditional ink is 5MPa at 23 ℃ s. Flaxseed oil is 44mpa s. Soybean oil is 55mpa S (noirot, 2004). This difference will affect the absorption of ink on coated paper

2. Stability of anti splitting ability

under the same amount of water, the vegetable ink has a sharp response to adding water, and the transfer recovery is fast, which means that the water is limited and fast absorption. In addition, the mineral ink shows a decline in anti splitting ability, which is unstable water absorption. If the printing press is not properly managed, it may lead to excessive emulsification

source: Printing Art

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