JPH0133359B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an offset printing method that prevents poisoning of a catalytic oxidation catalyst for exhaust gas treatment.In the offset printing process, as shown in FIG. It is printed and dried in the drying device 4. Next, the paper 1 is coated with a coating agent by a coating device 5 in order to prevent stains caused by rubbing and to improve paper alignment. The paper 1 is sent from the cutting and folding machine 6 to the binding machine 7. When the printed paper surface dries, high molecular compounds, resin wax, high boiling point solvents, aldehydes, acrolein, etc. are contained in the exhaust gas and are discharged from the printed paper surface together with the organic solvent. When these exhaust gases are released into the atmosphere, the solvents they contain not only cause air pollution but also become a source of bad odors. Therefore, various exhaust gas treatment methods are being implemented to prevent pollution. The exhaust gas is treated and rendered harmless by a catalytic combustion deodorizing device that uses a catalyst. There are two types of combustion deodorization methods; one is a direct combustion method and the other is a catalytic combustion method. Compared to the direct combustion method, the catalytic combustion method has the advantage of lower fuel consumption and lower learning costs because it can process at a lower combustion temperature of 200 to 450 degrees Celsius, but it also maintains a long catalyst life from an economic standpoint. This is a necessary condition. Catalysts used in deodorizing equipment generally use catalysts in which precious metals such as platinum are supported on carriers such as alumina, which have relatively high activity and durability compared to base metal catalysts such as manganese. . However, since noble metal catalysts are expensive, if catalyst poisoning substances are contained in the exhaust gas, the catalyst will deteriorate and its life will be shortened, making it uneconomical. For this reason, conventional methods have been used to prevent catalyst poisoning substances such as dust mist from decreasing the activity of the catalyst by providing a removal device such as a filter. Conventionally, an emulsion containing organic silicone as a main component has been used as a coating liquid in a coating device. The coating liquids used in the above-mentioned coating device are shown in Table-1.

[Table] This is generally commercially available as an organic silicone emulsion, and its stock solution is usually used as a 1% to 50% aqueous solution. There are three types of coating devices: a brush type (Fig. 2), a roller type (Fig. 3), and a spray type (Fig. 4). In the brush method, a brushed roller 15 splashes the coating liquid onto a felt roller 16, and the coating liquid is applied from the felt roller to the printing paper surface. In the roller method, a coating liquid is attached to the surface of a metal roller 17 and applied to the printing paper. In the spray method, a spray gun 18 sprays the coating liquid onto the paper surface. As mentioned above, the purpose of providing this coating device is to apply a coating liquid to give a sliding effect to the paper surface, to prevent stains on the printed paper surface due to rubbing between the roller and the paper, and to improve paper alignment in the folding machine. . Humidifying the printing press also has the effect of preventing the generation of static electricity due to friction between the printing paper and the rollers and improving paper alignment. When an emulsion containing organic silicone as the main component is used as a coating liquid, the organic silicone is sucked into the dryer along with air from the opening for the printing paper in and out of the dryer, cooling exhaust gas, combustion air fan, etc., and is absorbed into the drying exhaust gas of the printing paper. It is entrained in the air and mixed into the exhaust gas deodorization equipment. Such organic silicone is difficult to remove with a filter, and methods have been devised to remove it using an adsorbent or the like. However, when these removal methods contain large amounts of catalyst poisoning substances such as organic silicones at high concentrations, the removal equipment becomes large-scale, resulting in equipment costs and
Operating costs will also increase. Furthermore, if the exhaust gas is at a high temperature, there is a limit to how much it can be treated with adsorbents or the like. The organic silicone mixed into the deodorizing device is burned on the catalyst of the deodorizing device along with other malodorous components. At this time, the organic silicone is also catalytically burned, and fine Sio ^- covers the catalyst pores, reducing the activity of the catalyst, resulting in a decrease in deodorizing performance. The present inventors conducted various studies as a means to extend the life of the catalyst, and as a result, they completed the present invention by using a specific coating liquid. The present invention consists of a printing process, a drying process, a catalytic oxidation process using a catalyst for the exhaust gas generated in the drying equipment, and a coating process, and the exhaust gas from the coating process is also subjected to a catalytic oxidation process using a similar catalyst. The present invention relates to an offset printing method characterized in that the coating liquid used in the coating step is an emulsion containing polyethylene oxide as a main component or an emulsion containing a higher fatty acid ester as a main component. Since a suitable coating liquid was used, the life of the catalyst in the catalytic oxidation process is not shortened. Experimental examples and examples of the present invention will be described below. Example 1 Table 2 shows the results of a suitability test conducted on several types of coating liquids that were used to replace emulsion containing organic silicone as a main component.

【table】

[Table] From the results of this test, it was found that the most effective coating solution was an emulsion containing polyethylene oxide or higher fatty acid ester as a main component. FIG. 5 compares the concentration of the coating liquid and the slip imparting effect (relative dynamic friction coefficient) between these coating liquids and an emulsion whose main component is organic silicone using coated paper. Emulsions containing polyethylene oxide as a main component have a large slip-imparting effect even at low concentrations. Typical compositions of emulsions containing polyethylene oxide and higher fatty acid esters as main components are shown in Table 3.

【table】

[Table] Surfactants other than those shown in Table 3 may be used as emulsifiers. For example, sulfosuccinate type surfactants may also be used to improve wetting properties. Example 1 The effect of using the coating liquid shown in Table 3 was compared with that of an emulsion whose main component is organic silicone, and the results are shown in Table 4. As you can see from this table, when using substitutes,
It can be seen that the activity of the catalyst in the deodorizing device used in the offset rotary printing system is less likely to decrease.

【table】 [Brief explanation of drawings]

Figure 1 is a flow sheet for the offset printing method.
2 to 4 are schematic diagrams showing the coating method, and FIG. 5 is a graph showing a comparison of relative dynamic friction coefficients depending on dilution.

Claims (1)

[Claims] 1 Offset printing consists of a printing process, a drying process, a catalytic oxidation process using a catalyst for exhaust gas generated in the drying equipment, and a coating process using a coating agent, and the exhaust gas from the coating process is also subjected to a catalytic oxidation process using a similar catalyst. 1. An offset printing method, wherein the coating liquid used in the coating step is an emulsion containing polyethylene oxide as a main component or an emulsion containing higher fatty acid ester as a main component.