Filter paper: innovation in simple

For the first time, filter paper began to be used in ancient China, of course, for this purpose, the usual material was used, but the principle was laid. Currently, it is produced only at several specialized enterprises. This is due to the fact that the filter paper, despite its seeming simplicity, is a product for which a whole range of technologies is involved. In addition to the cellulose base, it contains special fibers and chemicals, dyes, polymers. Filter paper is used to purify oil, fuel and air streams in automotive engines, power units and engines for agricultural machinery. It is used for filtration in gas turbines, industrial compressors, diesel engines of railway vehicles. In addition, laboratory filter paper is used for analysis in the food industry (sugar, beer and wine), as well as in a number of other industries.

Such a wide range of applications of the material is provided by the unique properties of each of its kind, designed specifically for a particular purpose. The indicators depend on the initial components and conditions for further use. Therefore, the task of the technologists responsible for the production of this material is to ensure that the filter paper conforms to the physico-mechanical and chemical characteristics of the often aggressive media in which it will be used.

The process of its manufacture has the purpose of giving it a certain porous structure that will ensure a deep containment of foreign impurities from the filtered gases and liquids. In this case, the filter paper must have certain strength properties, which basically give it a uniform distribution of fibers in the material and a deep impregnation of the substrate with polymeric binders. The technology of its production consists of three main stages: the synthesis of the fibrous composition, the preparation of the base, the impregnation of the paper base with a binder polymer.

A large number of components can be used for the third operation. True, most often in modern industry, styrene-acrylic copolymers (acrylic impregnation), phenol-formaldehyde resins (phenolic) are used. The first has a number of advantages. In particular, when manufacturing paper with acrylic impregnation there is no need for an additional technological operation - heat treatment, such filters are also considered environmentally friendly, which is especially important for air treatment. Phenolic impregnation is a traditional way of producing material for the automotive industry. Two types of resins (novolac or resole) or mixtures thereof can be used. The main advantage of novolak in comparison with resole is a lower content of free phenol.

In the filters paper can be installed after embossing, as well as in several layers, which can be of different varieties. This increases the working surface, strength, spectrum of types of captured particles.