That is why the quality of the paper is of great importance even in the production of packaging products. The use of paper with defects lead to a decrease in quality as the surface layer and the whole product as a whole. External defects Paper The quality of the paper must meet certain requirements and standards, and deviations from them more than the allowable limit are called defects. The external signs of defects include rough material - cloth or mesh - machine manufacture of paper, folds, wrinkles, bubbles, holes, matte stripes, small particles, nonuniform thickness, slant sheets. Typically, the above-mentioned defects are the result of violations of manufacturing technology.
The uneven thickness of the paper is uneven thickness of the paper implies irregularity and other characteristics: moisture, strength and density. In this regard, reducing the quality of both the material and products for the production of which it is used. Low density paper contributes to its rupture, resulting in cost overruns in printing inks, and is too high leads to overuse of fibers and makes the material more difficult. At paper production should be strictly controlled according to the thickness and weight of 1 m2 of the lower limit allowed by the standard. There are special types of paper, the front layer is smooth, and the seamy - more porous. Typically, such products are intended for the production of posters and labels, glued to smooth surfaces. Curl the paper says the heterogeneity of such factors as humidity, orientation of fibers in the different parts of the upper and lower layers, and can also indicate the discrepancy between the norms of raw materials for manufacturing or material breach of conditions of production.