Offset paper: application and varieties

Offset paper is a material that is primarily intended for creating illustrative text publications and printing of visual products. The density of sheets for offset printing varies from 60 to 220 g / m. Often the product is positioned as a high-strength paper produced from pure cellulose with the inclusion of wood pulp, which has resistance to deformation under the influence of a moist medium.

Since offset paper is used in printing, its quality is subject to stringent requirements, which are caused by printing technology. The most important parameters include stiffness, strength, sizing, absorbency and dimensional stability when wetted.

According to the technology of offset printing sheets contact with a rubber cloth, which requires the product of excellent structural mechanical properties. To increase the strength of the material during production, reduce its dustiness and plucking. To do this, the surface is glued with a special composition, into which additives and fillers are added.

With the sizing, the offset paper acquires an increased moisture resistance. In cellulose fibers, water hardly penetrates, but this does not interfere with the fastening and absorption of the paint. In principle, absorbency is the most important property of the material. If the sheets are waterproof, moisture can not penetrate the paint and remain on the rubber sheet of the printer. If the absorbency parameters exceed the norm, the product will begin to receive the dye already from the blanket cylinder, which will cause softening of the surface layer.

Offset paper is used in books. It has found application in the production of catalogs, leaflets, brochures, flyers and other promotional and promotional materials. In addition, the material is used for the publication of black and white and color newspapers and magazines.

The service life of the offset paper depends on the wood pulp content. For the production of periodicals it is better to use sheets with a content of these substances not more than 75 percent. For the production of printed products that require a long shelf life, you need to purchase pure cellulose materials.

Offset paper, the price of which is higher than other similar products, is divided into coated, cartographic, newspaper and offset. For printing color publications with halftone illustrations of a long service life, materials made from bleached pure cellulose are used.

Also, paper is divided into brands. Category "A" serves for the issuance of publications that have an average shelf life. Mark "B" is used for production with a simple color separation and reduced brightness. For the production of newspapers, high-grade offset paper is used, which has an improved quality, characterized by increased breaking length.

Coated sheets can have both single- and double-sided coating, medium smoothness, increased whiteness and plucking resistance. This type of material is often used to create illustrative products.