The Significance of Additive Technology to Packaging and Printing Industry

In the process of manufacturing plastics and inks, in addition to the matrix resin as the main raw material, it is also necessary to add some substances in the resin that can improve the use properties or processing characteristics of the plastics and inks. Such substances are additives and additives for plastics and inks. . Additives are both organic and inorganic; both single and mixed; both low and high molecular weight. With the wide application of high-tech processing technology in the plastics, packaging and ink industries, additive technology as an important part of the technological innovation of the packaging and printing industry has gradually become the focus of innovation in the industry.

Improve processing and performance of plastics

Additive technology can effectively improve the processing properties of plastics, the mechanical properties of the film (such as shrinkage, rigidity, etc.), electrical properties (such as charge mobility, antistatic properties), optical properties (such as gloss, haze, etc.), weatherability Sex (anti-oxidation, anti-ultraviolet, high and low temperature suitability) and the use of packaging materials. For example, in the production process of films and bags, the surface properties and friction coefficient of the film are an important technical indicator. The coefficient of friction of the film is related to the type of additive (mainly anti-blocking agent), the amount of addition, the particle size, the shape, the dispersibility, and the degree of treatment thereof. Such as biaxially stretched polyester film commonly used additives are SiO2, TiO2, CaCO3, AL2O3, MgO and so on. As the added amount increases, the surface roughness of the film increases and the friction coefficient decreases. Reduce the coefficient of friction of the film to a value in the range of 0.3-0.4. In the printing and aluminum plating process, the binding force between the ink, the aluminum layer and the plastic film can be enhanced. In order to meet the requirements of high-speed automatic filling machines, some packaging bags should have a certain smoothness on the inner surface of the packaging bag. The smoothness of the film is generally obtained by adding a certain amount of a slip agent such as oleic amide to the inner layer material such as polyethylene particles. Due to poor compatibility of oleic acid amide and polyethylene, its molecules can easily migrate to the surface of the film, forming a weak interface layer. If the amount of slip agent is too high, the interfacial layer will weaken the adhesion between the ink, the adhesive and the film surface, and affect the quality of the product of the printing and dry reprocessing. We usually require that the coefficient of kinetic friction of the inner surface of the polyethylene film be in the range of 0.2-0.4. When blowing polyethylene film, adding a very small amount of low-molecular-weight fluoropolymer can effectively improve the processing and film-forming performance of linear low-density polyethylene (LLDPE) and metallocene-catalyzed polyethylene (mPE), and reduce the The viscosity at high temperature and high die-cut state reduces the friction between the melt and the screw, barrel, and die (lip), and in particular significantly improves the quality of the film. The antistatic agent can improve the electrical properties of the plastic film, strengthen the charge mobility, reduce the surface electrostatic charge, facilitate the high-speed processing of the plastic film during printing and compounding, improve the efficiency of the process of filling the powder product and the sealing strength of the packaging bag. . Additives in the process of high temperature, rapid die cutting process, it is easy to produce volatile matter, so that the packaging material odor. Therefore, it is necessary to select additives according to the use of packaging materials for the packaged products.

Increase the functionality of plastic materials

Adding a tackifier to the polyethylene resin can increase the tackiness of the film surface. A gas-phase rust inhibitor is added to the polyethylene resin to form a rust-proof film, which has a vapor phase rust prevention function, and exerts vapor phase rust prevention effect on the packaged metal products. In particular, the addition of degradation accelerators to plastic packaging materials, such as biodegradants, photodegradants, and thermal oxygen degradation agents, can effectively reduce the environmental pollution of plastic waste.

Significance in ink processing and use

Ink is used as an organic system composed of pigments, additives, binders, fillers, and solvents, and other chemical substances of different kinds and properties. It is necessary to increase the compatibility of various substances, increase the activity of pigments and fillers, and make ink properties. good. To achieve better printability, such as consistent color, good gloss, ink film strength, resistance to friction, anti-oxidation. Although the additive amount of the ink is small, it has an important influence on the viscosity, dryness, and color of the ink. There are many types of additives used in inks, including plasticizers, quick-drying agents, and slow-drying agents. The chemisorption and physical entanglement of the binder in the ink is more pronounced. The binder is beneficial to the affinity between the pigments, binders and fillers in the printing ink system, improves the adhesion and mechanical strength of the ink, reduces the thickness of the ink film, prevents the printing products from appearing floating color and hair, and eliminates the printing process. The occurrence of knife wire, stencil and other quality accidents; extend the ink storage period and so on. Antistatic agents used in inks can improve the antistatic properties of inks, increase printing speed, and eliminate various types of print quality problems caused by static electricity. The additive and its content are selected according to the basic properties of the printed substrate, such as electrical properties, printability, and process conditions, including differences in ambient temperature and humidity. If the ambient humidity is high, the film is not easy to dry under high printing speed conditions, the film is prone to blocking after printing, then the quick-drying agent should be properly added and the content of the oxidation promoter in the ink should be reduced; otherwise, if the environment is relatively dry Slow-drying agent should be added appropriately.

No additive can satisfy all conditions such as matrix resin, process conditions, material properties, and technical requirements. In practice, it is often necessary to scientifically select and optimize various additives so that a variety of additives work synergistically. Processing can also obtain superior overall performance.


From:China Printing Chemicals Network