Green lithography ink lithography suitability

Soybean ink has the advantages of printing quality and environmental protection. It has been applied to Zhang page type, rotary type, business form, elastic letterpress ink and so on. This study intends to test the viscosity, stability of splitting resistance, emulsification properties, particle size and other lithographic suitability of soy inks, and measure the concentration and gloss after the paper is developed, and then analyze and compare with traditional inks. To understand the difference in lithographic suitability between soybean inks and traditional inks.

I. Research motivation and background

The composition of a general lithographic ink includes a colorant, a medium, and some additives, wherein the medium is mainly a hard resin, a vegetable oil, and some non-vegetative 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 the composition of petroleum-based inks. Although soy ink contains the same pigments as petroleum-based inks, most Pigments are petrochemicals, however, soya bean inks can be partially decomposed and petroleum-based inks cannot be decomposed.

As for the production of soy inks, the 1979 American Newspaper Publisher Association (ANPA) advocated the development of alternative petroleum-based printing inks, which coincided with the second oil crisis. The OPEC The output of crude oil indirectly affects the supply of raw materials. In order to reduce dependence on imported crude oil, it has found that non-volatile and decomposable vegetable oils can also be used to make vegetable inks instead of petroleum-based inks, which can improve the rub resistance of newspapers. Sex. In addition, Volatile Organic Compounds (VOCs) in petroleum-based inks have caused ecological damage. Later, after more than 2,000 kinds of vegetable oils were tested by scholars, soybean oil containing soybean oil was considered to be non-toxic and available. The American Sun Chemical Company began producing soy ink and later introduced it into the newspaper industry. Now, soya bean ink has even been promoted to all parts of the world. Later, soybeans labelled with soy oil-containing ink were born. Taiwan is also being promoted in the printing industry (Wang Shouhong, 2004; PA Noirot, 2004; E. Axmear, 2004 Patterson, 2003).

In the printability of soybean ink, it has the following characteristics:

(a) Ink emulsification is weak, and it can maintain its rheological and water tolerance in more than 50,000 printed prints (B. Fuchs, 1991; SZ Erhan, 1992). .

(b) When the same amount of water is added, the response of soy ink to water is significantly sharper than that of mineral ink, the ink transfer is restored more quickly and cleanly, and soy bean ink has a relatively low splitting resistance (PA Noirot, 2004; B). Fuchs, 1991).

(C) In terms of ink viscosity, Boris Fuchs et al. (1991) showed that concentrated soybean ink has a relatively low viscosity, and PA Noirot (2004) reported that the viscosity of soybean oil is much greater than that of mineral oil at 23 °C. .

Soybean ink has the following advantages in printing applications:

(A) Good rub resistance, so that the reader is not troubled by black hands.

(b) No irritating odor.

(3) The color of the ink is strong and bright, so that the printing industry can use less ink, save costs and increase printing units.

(D) can reduce the expansion of outlets.

(e) In terms of environmental protection, soy bean inks contain 17% VOCs of petroleum-based inks, which can be described as non-toxic inks (E. Axmear, 2004).

(6) It has good deinking properties and can be backfilled for recycling in black ink, which is environmentally friendly and low cost (B. Simpson, 1994).

As for the shortcomings, the price of soya inks is higher than that of petroleum-based inks, which is a black ink used for newspaper printing, which is about 25% more expensive. Soybean inks dries more slowly than mineral inks (PA Noirot, 2004). Soybean ink still faces some problems in the application of lithography, such as the surface of the printed product is easy to dry due to ink is not completed, resulting in the stained surface of the printed matter, and the difference between the hue and the final draft is large, the color gloss is poor, the picture performance level is insufficient No stereoscopic effects, etc., but also the problem of insufficient black ink concentration and poor balance between yellow ink and ink (Lu Lihua, 2004).

Based on the characteristics and problems of the above soy inks, this study intends to conduct experimental analysis on the printability of soybean inks in lithography, and compares the differences in printability between soybean inks and general lithographic inks, and on lithographic printing of soybean inks. Characteristics are discussed.

Second, the purpose of the study

In this study, a group of lithographic soybean ink inks of cyan, magenta, yellow, and black inks were tested with a set of general lithographic printing inks in four colors to investigate differences in the printability of soy inks and general inks, and to provide results. The printing industry serves as a reference.

The purpose of this study includes:

(a) Explore the differences in lithographic suitability between soy inks and traditional general inks, including the stability of ink resistance, viscosity, emulsification rate, and particle size.

(2) Explore the differences in the concentration, hue, and gloss of soy bean inks and conventional inks in paper color development.

(3) From the stability of the ink splitting resistance, calculate the regression curve equation for the stability of the splitting resistance of soy ink.

Third, the research process

The purpose of this study was to investigate the differences in lithographic suitability between soybean inks and general inks. Therefore, a group of soybean inks was used as the experimental group, and a group of general inks was used as the control group to compare and analyze the printability of soybean oil inks.

è´°, literature discussion

First, vegetable ink

The inks used in today's printing, in addition to traditional inks, have also developed many environmentally friendly inks. In order to meet the environmental requirements of the ink, we must first change the ink composition, that is, the use of environmentally friendly materials to formulate a new type of ink. The main environmental protection inks today are water-based inks, UV inks, and vegetable oil-based inks.

(1) History

In the 1980s, the American Press and Publication Association (ANPA) developed a series of ink formulations that mixed hard and tall oil fatty acids with carbon black pigments, but these inks were limited by price and The availability of oil, together with the difficulty of cleaning up the asphalt, has not been completely accepted by the industry. Later, in 1985, an improved version of ANPA developed a medium for lithographic newsprint printing, including alkaline refined soybean oil, hydrocarbon resins and pigments (Wang Shouhong, 2004; Noirot, 2004; Axmear, 2004; Patterson, 2003).

(b) Construction

There are three basic types of vegetable oils in vegetable inks:

1. Drying oil: In the printing process, when the oil is exposed to oxygen, it changes from a liquid to a solid, where the oxygen controls the action of the catalyst. In the past, the users of the ink industry generally concentrated on dry oil. The medium in traditional inks usually contains linseed oil or other dry oils. It also contains some petroleum substances as solvents in the medium.

2. Semi-drying oils: Vegetable oils generally use semi-dry oils such as soybean oil, corn oil, rapeseed oil, and tall oil to replace the petroleum substances in the ink formulation.

3. Non-drying oil.

From the molecular structure of ink, vegetable oil molecules are very different from mineral oil molecules. Mineral oil molecules are three to five times smaller than vegetable oil molecules regardless of branching. Due to differences in molecular structure, vegetable oils are much heavier than mineral oils, so vegetable oils can hardly be fixed and dried under heat (Noirot, 2004).

(c) Characteristics

Viscosity

The viscosity of the oil used in traditional inks is 5 mPa.s at 23 °C, 44 mPa.s for flaxseed oil and 55 mPa.s for soybean oil (Noirot, 2004). This difference affects the ink on coated paper. Absorption. (Noirot, 2004).

2. Stability of splitting resistance

In the same amount of water added, plant-based inks respond sharply to the addition of water, and the rapid recovery of transfer means that the water is limited and fast to absorb. In addition, the mineral ink shows a decline in the resistance to splitting and is unstable. Moisture absorption, if not properly managed, may result in over-emulsification.

Reprinted from: Graphic Arts