Countermeasures for High Speed ​​of Web Offset Printing Ink

3, liquidity and adhesion

High speed will increase the line speed of the crucible and cause the printing pressure to drop. In particular, this condition is more pronounced in a single operation, resulting in a decrease in the adhesion and fluidity of the ink. It can be imagined that the impact of close-packing will be even greater.

If the relationship between the viscosity and fluidity of the ink cannot be well balanced, problems such as uneven adhesion, spots, and deposition of the ink roller may occur. From this point of view, the viscosity and fluidity of the ink are also contradictory to each other. It is a very important link to properly balance the proper viscosity and fluidity when designing inks for high-speed printing presses.

4, emulsification balance

The emulsification balance of ink is one of the most important features related to almost all aspects of printing. Along with the speeding up of printing, it is very important to make accurate predictions by grasping the amount of water in the layout, how the emulsification state on the roller changes, and how viscoelasticity of the emulsified ink is. The viscoelasticity of the emulsified ink is an important factor influencing the ink flowability on the printing press. If the viscoelasticity change of the emulsified ink can be grasped in real time, this has a great influence on the printing applicability of the ink by taking the flowability of the ink as the center. help. For this purpose, the company also independently developed a set of measuring devices for measuring the viscosity of emulsion inks.

Third, environmental measures

The use of lithographic inks has a long history. Recently, due to the limitation of VOC emissions and its environmental adaptability, soybean oil ink (SOY) has been favored by the industry. In the United States, soy oil inks are gradually replacing mineral oils that use condensing rotary offset color inks and are used in newspapers, telephone books, and other printing.

In addition, ink manufacturers in Japan almost all began to use the ink solvent to remove the aromatic (less than 1%) AF solvent.

1, environmental protection product certification standards

This standard is the standard that the Japan Environmental Association evaluates products that make a great contribution to the field of environmental protection. Among them, the following regulations are made for inks:

The aromatic content in the solvent used is 1 or less.

2 Ink complies with NL (Regulations for printing inks for food packaging materials).

3 The ink consumes no significant increase in energy during manufacture and use.

4 The effect of the deinking on the environment is not greater than that of previous products.

2. Soybean Ink Recognition Standard This standard was developed by the American Soybean Oil Association for the popularization of soybean oil. The soybean oil used in Table 3 is approved by it.

Table 3: Identification Standards for Soybean Ink Leaf Paper Ink Offset Offset Printing Newspaper Newspaper Soybean Oil 20% 7% Ink 40%, Other 3 Colors 30%

3, recycled paper measures

With the progress of deinking technology and the need for environmental protection, the utilization rate of recycled paper has been increasing. However, there are no doubts about the defects of recycled paper, such as weak surface strength, poor moisture resistance (weak surface hardness in wet state, easy hair removal, sticky rollers). These recycled papers often make the blankets full of dust, causing picture pollution. Therefore, in the future, starting from the ink aspect, the development of "low viscosity, high viscoelasticity inks" with "highly soluble varnish made of polymer materials" has become a prominent requirement in the printing industry.

5. Incineration of printed materials and dioxin contamination

Recently, dioxin pollution caused by incineration has gradually become a social issue. Including the ink manufacturers, there are still many unclear places for the production of dioxins. From the situation that has been mastered can be summarized as the following:
1 The lithographic ink uses raw materials that are completely free of dioxins.

2 Chlorine-free materials do not produce dioxin when burned. Chlorine-containing materials can inhibit the production of dioxins when burned under proper conditions.

Some of the raw materials used for the 3 lithographic ink contain chlorine compounds, and the external printing paper also contains trace amounts of chlorine.

4 There is a close relationship between the burning conditions and the production of dioxins. Therefore, the Japanese government called on all manufacturers to strictly abide by the standards for waste incineration and the standards for pollutants stipulated in the Waste Disposal Act and the Air Pollution Control Act, which were issued on August 29, 1997 and began on December 1, the same year. .

As shown above, although dioxin pollution cannot be expressed in terms of specific figures, it can be seen that the use of lithographic printing inks is much less harmful than ordinary household waste.

At this stage, the development trend of thermosetting web offset printing in Japan is good. However, along with the progress of high-speed processes and the development of environmental requirements, it is also facing a severe test. In short, accurately grasping issues and responding quickly in the future is an important task for the industry to follow.