Taishan (Red General) cigarette package gravure water-based ink research

In 2013, our company launched the “Development and Application of White Paper Gravure Water-based Ink” project, which lasted for three years and realized the mass production of “Taishan (White General)” gravure water-based ink products in the second half of 2015. In contrast, the printing process of “Taishan (Red General)” cigarette pack is difficult, but our company is not afraid of difficulties. Through the process adjustment and repeated tests, the “Taishan (Red General)” cigarette package has been successfully realized. The application of printing water-based red ink and water-based varnish, Figure 1 is our company's gravure water-based ink cigarette package. Below, the author will focus on the research and development improvement and promotion of the "Taishan (Red General)" gravure water-based red ink and water-based varnish cigarette products.

Figure 1 Our company gravure water-based ink cigarette package products

Production process improvement plan

1. Paper performance adjustment

According to the characteristics of the gravure water-based ink, a non-fluorescent white cardboard with a basis weight of 230g/m2 is tailored. By adjusting the paper performance, the printing suitability of the coating layer on the paper surface is improved, and the surface coating quality is stable and suitable. The ink absorption performance ensures the printing effect. At present, domestic cigarette-grade non-fluorescent white cardboard can basically meet the printing requirements of gravure aqueous ink.

2. According to the main characteristics of gravure aqueous ink, study the best formula of ink

(1) Components and effects

The gravure aqueous ink is mainly prepared by mixing, grinding, dispersing and filtering water-soluble resin, pigment, water (water and co-solvent), auxiliary agent and the like. Among them, the water-soluble resin is mainly used to encapsulate the dispersed pigment, so that the ink can be well transferred to the surface of the substrate; the pigment generally includes organic pigments and inorganic pigments, which develop color and color in the ink; water is mainly used as a dilution carrier. The co-solvent is mainly used to increase the solubility, generally a small amount of alcohol solvent; the auxiliary agent is mainly used to help improve the shortcomings of the ink, mainly defoaming agent, dispersing agent, leveling agent, anti-wear agent, thickener, Preservatives, etc.

(2) fineness

The fineness of the gravure aqueous ink is related to pigments, resins and the like, and is one of the important indexes of the gravure aqueous ink. The coarse particles of the gravure aqueous ink not only affect the service life of the doctor blade and the printing plate, but also the ink itself is liable to precipitate and the leveling property is also deteriorated. Therefore, in view of the depth of the plate pocket, the thickness of the ink layer, and the economic impact of the polishing, the fineness of the gravure aqueous ink is generally required to be 15 μm or less.

(3) Viscosity

When the printing machine is used, the viscosity of the original ink is generally high, and it is necessary to add an appropriate amount of water or a mixture of ethanol and water (the ratio of water to ethanol is generally 1:1 to 1:2) for dilution. If the viscosity of the gravure aqueous ink is high, bubbles are easily generated, resulting in false printing or pinhole phenomenon; if the viscosity is too low, the printed font becomes thick, the edge of the pattern becomes blurred, and the printing quality is unstable. When adjusting the viscosity of the gravure aqueous ink, the water and the alcohol solvent should be mixed in a certain ratio in advance, and then the ink is added while stirring. Generally, the viscosity of the ink is measured by using the 2# Chaen cup, and the viscosity is preferably 19 to 21 s. It should be noted that the alcohol solvent cannot be added to the ink alone, otherwise the ink will be coarsely deteriorated.

(4) pH value

At present, gravure aqueous inks on the market are generally alkaline, mainly because most of these products use alkali-soluble binders. In the production practice, we found that the control of the pH value of the ink is also important, and it is usually controlled at 7.5 to 9.0. At this time, the performance of the gravure aqueous ink is very stable, and the stability of the printing quality can be ensured.

According to the characteristics of gravure aqueous ink, after repeated trials, the best gravure aqueous ink formulation is determined: 10% to 20% high pigment, 30% to 40% acrylic resin, 1% auxiliary agent (dispersant) , defoamer, anti-wear agent), 0.8% trace aid (X, Y, Z), 30% to 40% solvent (water, ethanol). Through experiments, it was found that when the ratio of water to ethanol is 1:4, the printing effect is ideal, but it needs to be fine-tuned according to the season and the characteristics of the printed products.

3. Improvement of the drying system

Drying is an important part of gravure printing ink printing. In addition to the drying speed of the gravure aqueous ink itself, it is also related to the depth of the printing plate and the temperature of the oven. Generally, the hot air temperature during the gravure drying of the paper should be Controlled at 80 to 110 °C. In addition, the drying effect of the gravure aqueous ink can also be improved by appropriately increasing the ventilation amount and heating power of the gravure oven.