Offset paper is a material that is primarily intended for the creation of illustrative text publications and printing of graphic products. The density of sheets for offset printing varies from 60 to 220 g / m. Often, the product is positioned as high-strength paper made from pure cellulose with the inclusion of wood pulp, which has resistance to deformation under the influence of a humid environment.
Since offset paper is used in printing, strict quality requirements are imposed on its quality, which are due to printing technology. The most important parameters include stiffness, strength, sizing, absorbency and dimensional stability when wetted.
According to the technology of offset printing, the sheets are in contact with a rubber sheet, which requires excellent structural mechanical properties from the product. To increase the strength of the material during production, reduce its dustiness and pluckability. To do this, the surface is glued with a special composition to which additives and fillers are added.
Using sizing, offset paper gains increased moisture resistance. Water hardly penetrates cellulose fibers, but this does not interfere with the fixing and absorption of the paint. In principle, absorbency is an essential property of the material.
If the sheets are waterproof, then moisture will not be able to penetrate the ink and will remain on the rubber sheet of the printing device. If the absorption parameters exceed the norm, then the product will begin to receive dye already from the offset cylinder, which will cause softening of the surface layer.
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Coated sheets can have either single or double-sided coating, medium smoothness, high whiteness and resistance to plucking. This type of material is often used to create illustration products.