Cause analysis of the most popular cigarette label

Analysis of the causes of cigarette label odor

the environmental protection of cigarette labels is reflected in many aspects. But one of the most important indicators is "solvent residue". It has a direct impact on the environmental protection of cigarettes and is the main factor for cigarette enterprises to encounter the "green trade barrier" of western developed countries in the future

the generation of cigarette label odor is mainly due to the volatile chemical components remaining in the cigarette package, which will continue to volatilize after the cigarette package is printed and processed, and then produce odor. Factors such as paper, ink, printing process, packaging and storage form of finished cigarette labels used in cigarette package printing and processing are all the inducements that lead to the smell of printed products

1. factors that constitute the smell of paper

printing paper is composed of plant fibers, excipients, pigments and other chemical additives. It is the latex in the coating (such as styrene butadiene latex in domestic paper) that has a great impact on the smell of the paper itself, and other auxiliary additives such as hydration resistance agent, lubricant, dispersant and defoamer also have an impact. These components are easy to escape some organic substances and produce slight odor when exposed to UV radiation and high-temperature drying,

2. The main factor that constitutes the odor of cigarette labels is the residue of ink solvent

the inks used in gravure printing are volatile dry inks, and the connecting materials in the inks are composed of resin and solvent. During the evaporation and drying process of ink, if the solvent volatilizes incompletely, it will cause part of the solvent to remain in the ink layer and produce odor

(1) selection of solvents

● choose solvents suitable for environmental protection

the world-famous tobacco group has clear requirements for "cigarette label solvent residue limit". Specify in detail the volatile substances strictly prohibited in gravure printing products of the factory. The allowable amount of volatile substances is also limited and the industry has exceeded the 50million tons of annual target task variables confirmed in the government work report, and the total amount per square meter is clearly specified. These advanced technical standards undoubtedly point out the way for our choice in cigarette label printing

● choose a solvent with appropriate volatilization rate

similar solvents, the lower the boiling point, the faster the volatilization rate. However, when the boiling point of different solvents is the same, the volatilization rate is not necessarily close. Therefore, when setting the process, the choice of solvent needs to be very careful

(2) main factors affecting solvent volatilization

the volatilization rate of solvent is not only related to its own volatilization rate, but also affected by resin and pigment. Generally speaking, the easier the resin dissolves in the solvent, the slower the solvent escapes; The resin with high melting point has low solubility, and the solvent is relatively easy to volatilize. Therefore, the melting point of the resin used in high-speed gravure printing ink should not be lower than 150 ℃. However, if the melting point of the resin is too high and the ability to dissolve in the solvent is too low, it is easy to cause other problems. The surface characteristics and concentration of pigments will also affect the volatilization of solvents. The particle size and density of pigments are small, and the volatilization of solvents per unit area and per unit time is less. At the same time, the volatilization speed of the solvent is also matched with the base, supplemented by the aluminum alloy profile column with advanced plastic spraying treatment; The external steam pressure, temperature and air volume are related. In general, the greater the vapor pressure, the higher the temperature, and the greater the air volume, the faster the evaporation rate of the solvent

3. measures to reduce product odor

at present, in view of the above odor producing factors, we can adopt the following measures to improve in the process of intaglio cigarette label printing:

(1) choose environmental friendly raw materials. Among similar products, paper with high quality, relatively environmental protection and low odor (such as paper coated with pure virgin wood pulp or acrylic latex) and ink and solvent with low toxicity, low odor and not easy to retain odor are selected for production (such as environmentally friendly alcohol soluble ink or water-based ink)

(2) the design of products should avoid influence. In the design of new cigarette labels, we should try to use less large-area ink lamination technology; Try to avoid using materials that are easy to increase the smell of prints

(3) formulate a reasonable gravure printing process. Adjust and improve the printing process at any time according to the factors such as different pictures and texts, different materials, temperature and humidity in different periods, so that the volatile organic components that are easy to produce odor can be kept in the printing as little as possible. For example, the matching of ink system and the proportion of solvent used; The relationship between appropriate drying temperature, circulating air volume and machine speed; Formulate a printing color sequence that combines oxfab process to form materials with specific strength better than cast aluminum, magnesium and nylon, and accelerate solvent evaporation; Choose the right packaging form, etc

source: information of Chinese cigarette packet ink