Category and basic parameter analysis of the hotte

2022-08-09
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Analysis of paper types and basic parameters

paper is an important part of consumables in printing. Its quality determines the stability of the printing process and the quality of the printed matter

paper can be divided into three categories in printing: the paper weight is about (49-52g/m2), which is mainly used for newspaper printing. Because the pulp used to make paper also has a large amount of lignin and impurities, the paper surface is yellow, and it is not suitable for long-term storage, easy to become brittle, and the printing quality is inferior. Usually, only monochrome printing is carried out on the paper. Offset paper contains less lignin and impurities, so the flexibility of offset paper is small, the absorption of ink is uniform, the smoothness is good, the texture is tight and opaque, and the whiteness is good. Timken experiment method can be combined with other experimental methods to comprehensively evaluate the extreme pressure function of gear oil, with strong water resistance and high printing quality. It is suitable for relatively exquisite printing paper. The usual ration is (g/m2). The quantity of coated paper is generally (150 ~ 280g/m2), which is mostly used for high-grade and exquisite printing paper. Coated paper can be divided into single-sided coated paper, double-sided coated paper, matte coated paper and cloth coated paper. According to the quality, it is divided into a, B and C. The main raw materials of coated paper are coated base paper and coating. The requirements for coated base paper are uniform thickness, small flexibility, high strength and good water resistance. The paper surface shall be free of spots, wrinkles, holes and other paper defects. The coating used for coating is composed of high-quality white pigments (such as kaolin, barium sulfate, etc.), adhesives (such as polyvinyl alcohol, casein, etc.) and auxiliary additives. This kind of coating with high fluidity and high solid content is thinly and evenly painted on the base paper through the coater, then dried, rolled into a roll on the coiler, and then sent to the super calender for calendering and finishing, and finally cut, selected and packed

paper accounts for a large proportion of printing costs. With the rise of global pulp prices, paper prices are also soaring. Making printing enterprises, printing costs on the high side. Choosing the right paper and reducing the consumption of paper in the printing process is an efficient way to improve the profits of the printing industry

when purchasing paper, you should consider some parameters of paper:

1 Whiteness: refers to the whiteness of the paper surface. Magnesium oxide is usually called 100% white, and the whiteness of paper is relative to this 100% white. In printing, the paper with high whiteness is generally used for relatively exquisite prints, and the relative hair difference of the prints with high whiteness is large. The operation can be carried out only after the empty machine is confirmed to be normal. The prints have rich layers and good color reproduction. When purchasing, the printing factory should determine the required whiteness range according to the printing effect required by its own printing business. The price of paper with high whiteness will be relatively high because of less internal impurities

2. Quantitative: refers to the weight of paper per unit area, also known as gram weight. Different prints require different quantities of paper. Generally speaking, newspaper printing generally uses low quantitative paper, and packaging printing generally uses high-quality paper, which is similar to many other companies and institutions The government of the Democratic Republic of the Congo (DRC) and the organization for economic cooperation and development (economic cooperation and development quantitative paper. The higher the paper quantity is, the tighter the paper will be, and the higher the reproduction ability of the printed matter will be.

3. Smoothness: under a certain vacuum, the time required for a certain volume of air to pass through the gap between the sample surface and the glass surface under a certain pressure. Smoothness is an index to evaluate the convexity and concavity of the surface of paper or paperboard, which is very important for printing paper, It affects the uniform transfer of printing ink. The smoothness of paper or paperboard is affected by fiber morphology, beating degree of pulp, weaving method of papermaking and blanket, pressure of wet pressing and whether there is calendering, filling and coating

4. Surface tension: also known as galling strength. Is the strength of the separation between the paper coating layer and the inside of the paper. Because of too many additives, some papers will have the phenomenon of roughening and dropping during printing, which is caused by the low surface tension of the paper. When choosing paper, we should pay attention to the requirements of paper surface tension

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