What are the characteristics of paper used in student books?

What are the common printing papers? Basic knowledge of printing and packaging

Paper knowledge

1. Commonly used papers , offset paper, coated paper, white paper

Paper is a thin layer of material in which plant fibers are tightly intertwined. So as far as paper is concerned, its basic component is plant fiber. Paper is a plant fiber that has been chemically and mechanically treated. They are intertwined and form a porous film layer. Paper for different purposes should have special properties based on the same properties. These special properties are This is achieved by selecting the varieties of plant fibers or adding different proportions, varieties or quantities of additives, and processing with different mechanical equipment.

1. Offset paper (Dollin paper)

According to the proportion of paper pulp, offset paper is divided into three types: special number, No. 1 and No. 2, including single-sided and double-sided. There are two levels: super calendering and ordinary calendering. Paper weights are 50, 60, 70, 80, 90, 100, 120, 150, 180 (g/m2). Among them, the commonly used double-sided offset papers are 70, 80, 90, 100, 120 (g/m2). There are 50, 60, 70, 80 (g/m2) surface offset paper, etc.

Offset paper has small elasticity, uniform ink absorption, good smoothness, tight and opaque texture, good whiteness, and strong water resistance. Used for processing and manufacturing tissue paper packaging and decoration prints. When printing on offset paper, the paper should not be stacked too high. Especially for prints with high smoothness and large amounts of ink, it is necessary to prevent the back of the print from getting dirty. Anti-stain agents, powder spraying, or backing paper are generally used. Conjunctival offset printing ink and better quality lead printing ink should be used. The viscosity of the ink should not be too high, otherwise powder removal and fuzzing will occur.

Flat paper specifications: 787×1092, 850×1168, 880×1230 (mm×mm).

Web specifications: width 787, 1092, 850 (mm).

Usage: Offset paper is mainly used for lithographic (offset) printing machines or other printing machines to print higher-end color printed matter, such as color pictorials, albums, posters, color-printed trademarks and some high-end book covers and illustrations wait.

2. Coated paper

Coated paper is also called coated paper. This kind of paper is made by coating a layer of white slurry on the base paper and undergoing super calendering processing. High-grade printing paper, also known as printing coated paper. The whiteness is high, the paper fiber distribution is even, the thickness is consistent, the elasticity is small, the elasticity is good, the water resistance and tensile properties are strong, and the ink absorption and reception are very good. The pressure should not be too high when printing on coated paper, and offset resin-based inks and glossy inks should be used. To prevent dirt from sticking to the back, methods such as adding anti-fouling agents and powder spraying can be used.

There are two types of coated paper: single-sided and double-sided. Weight: 70, 80, 100, 105, 115, 120, 128, 150, 157, 180, 200, 210, 240, 250 (g/m2); including: 105, 115, 128, 157 (g/m2) imported There are many paper specifications.

Flat paper specifications: 648×953, 787×970, 787×1092 (currently there is no roll paper in China). 889×1194 is the specification of imported coated paper.

Coated paper is mainly used for printing albums, covers, postcards, exquisite product samples and color trademarks.

3. White paper

White paper is a kind of outer packaging paper, used for printing various trademarks and packaging cartons. The weight is 220, 240, 250, 280 , 300, 350, 400 (g/m2); Flat paper specifications: 787×787, 787×1092, 1092×1092 (mm×mm).

White paper is composed of lining and batter. The batter is white, and the lining is generally the true color of the raw materials. White paper is divided into two categories according to paper surface: pink white paper and ordinary white paper. According to the bottom layer, there are two types: gray bottom and white bottom. The quality requirements of white paper are: white, smooth, consistent thickness, firm texture, no dusting or linting, uniform ink absorption, small expansion, toughness, and no breakage when bent.

Mainly used for printing packaging boxes and product decoration lining paper. In book binding, it is used for binding materials such as the inner cover of simple hardcover books and the diameter paper (spine) of hardcover books.

4. Letterpress paper

Letterpress paper is the main paper used for letterpress printing of books and magazines. Letterpress paper can be divided into four grades: No. 1, No. 2, No. 3 and No. 4 according to the different composition ratios of paper materials. The number of the paper represents the quality of the paper. The larger the number, the worse the paper quality. Paper weight: (49～60) ±2 (g/m2); flat paper specifications: 787×1092, 850×1168, 880×123...

What are the characteristics of pulp

Types and characteristics of pulp

Pulping is the first step in the papermaking process, which is the dissociation of wood into fibers. The choice of pulping process depends on the tree species and the end use of the paper. There are two main methods of pulping from fresh wood: mechanical and chemical.

Mechanical pulp

Mechanical pulping uses mechanical force to separate fibers. There are two basic methods: A. Grind logs about 1 meter long. The barked tree trunks pressed against the rotating grindstone. B. Feed the wood chips into the refiner, and the wood chips are separated into fibers between the two rotating grinding discs of the refiner. Pressure and heat are used to speed up the process.

Chemical Pulp

Today, the most commonly used chemical pulping process is the sulfate process. This method uses an alkaline cooking liquid and works on almost all woods. UPM Paper uses this method to make pulp.

Paper produced with 100% chemical pulp is called fully chemical wood pulp paper. The wood is cooked in a chemical solution to remove the natural binder lignin between the fibers. This makes the paper less prone to odor. Yellow discoloration, longer storage. Modern chemical pulp mills can be energy self-sufficient because the part of the wood raw material dissolved in the cooking liquor can be collected and used as fuel.

Regenerated fiber pulp

Regenerated fiber is produced from recycled waste paper. It is a high-quality and economical raw material, especially suitable for the production of newsprint. Recycled waste paper needs to be deinked before it can be reused, and the deinking process requires some chemicals and a certain amount of energy. In theory, a fiber can be reused 5 to 7 times, and this fiber loss means that virgin fiber must be used to maintain the balance of fiber volume.

The preparation process of deinked pulp has multiple steps: including dissociation of paper in water, multi-stage slag removal, deinking, and sometimes bleaching. There is a basic rule to follow when using recycled waste paper to produce new printing paper: only light-colored recycled waste paper (newsprint, magazines, advertising materials) can be selected as raw material.

There are two methods of deinking: washing and flotation. Washing uses more water than flotation. The flotation method is to spray air into the slurry to form a large number of small bubbles. As a carrier of flotation, the ink immediately adheres to the bubbles and floats to the surface together, where it is collected. and remove.

Usually, each ton of recycled waste paper will produce 100-150 kilograms of deinked material. These wastes can usually be burned to produce energy, and the ash produced by incineration can be used for concrete and road construction. adhesive required.

Pulp Bleaching

Bleaching whitens the pulp and removes impurities. The pulp is bleached in a continuous multi-stage reaction. The type and amount of bleaching chemicals used depend on the pulping method and the desired brightness. Wood pulp can be bleached with elemental chlorine, chloride, ozone and different forms of oxygen and hydrogen peroxide. For environmental reasons, UPM Paper does not use chlorine in its own bleaching process and does not purchase pulp bleached with chlorine.

What are the characteristics of paper used in homework books?

I haven’t used it in many years and I miss it! The paper used to wrap books is different in size, and the size of the book you want to wrap is also different. If you like it, go to the store and check it out for yourself