1. Trees 

　　Paper and paper paddles can be made from a variety of plant fibers, but the most commonly used raw materials for paper are trees and non-wood types。 

　　2. Chemical composition of wood 

　　The following table shows the typical chemical composition of coniferous and broad-leaved wood。However, it is difficult to accurately write down the chemical formula of wood, because wood is a complex and uneven natural product composed of a variety of molecular compounds。The main components of wood are cellulose (40-50%), hemicellulose (20-35%), wood (20-30%) and solvent dissolved substances (3-3, 5%).。However, it can be said that it is impossible to separate these chemical components without structural changes and decomposition。If you study what the main components of wood are, then most of it is composed of polysaccharides, about 60-80%;If the polysaccharide of wood is decomposed with dilute acid and water, it can be known that it is a polymer carbohydrate composed of monosaccharides such as glucose, mannose, and xylose。 

　　The main polysaccharide components of wood can be divided into cellulose, cellulose and hemicellulose

　　When the whole cellulose is treated at room temperature with a dilute base (for example, with 17, 5% NaOH or 10-24% KOH), 15-30% of the dissolved wood is hemicellulose, and the insoluble is cellulose。 

　　Three, pulp 

　　The raw material of paper is pulp, which is mainly made of wood, and its manufacturing method is generally as follows: chemical pulp pulp semi-chemical pulp mechanical (physical) pulp 

　　 1. Chemical pulp 

　　Chemical pulp is in the process of manufacturing pulp, mainly made of chemical pulp, of course, according to the use of drugs and manufacturing methods, there are certain differences。Compared with the process of removing the intermediate layer lignin and cell lignin in raw materials, pulp has the disadvantages of low utilization rate of raw materials and high production cost。 

　　(1) Kraft pulp 

　　Kraft pulp is a chemically produced pulp also known as sulfate pulp。The word Kraft means strong in Sweden。Because the pulp made by the Swedish chemical factory from the by-product glauberite is very strong, it is called kraft paper。 

　　(2) semi-chemical pulp 

　　Semi-chemical pulp is a kind of pulp made by chemical treatment, which first removes part of the lignin contained in the wood, and then mechanically breaks the remaining softened wood chips。That is to say, in the manufacturing method, chemical treatment and mechanical treatment are equally divided。The purity and strength of semi-chemical pulp is higher than that of shredded wood pulp, that is, mechanically treated pulp, and the yield is higher than that of chemical pulp made by chemical methods。 

　　2, waste paper pulp 

　　The so-called waste paper pulp is the waste paper that has been used, and it is put into the dispersal machine device like the juice strander, and the fiber that is clustered together is twisted back and forth to decompose into porridge。 

　　The waste pulp used for the surface layer of corrugated cardboard is mainly raw materials such as kraft paper and corrugated paper scraps, so the strength is very high。 

　　Second, the distinction between paper and cardboard 

　　According to its thickness is divided into paper and cardboard, it is customary to square the weight of more than 200g thick paper called cardboard, less than 200g weight called paper。However, with the improvement of mechanical equipment, materials and process technology，The emergence of thin paper cardboard also known as light corrugated paper and cardboard，Its scope has exceeded the 200g secular regulations，In the production machinery is also divided into heavy corrugated cardboard production line and light corrugated cardboard production line，Our company's existing three cardboard production lines are light cardboard production lines。 

　　There are about 5000 kinds of paper and board in the world，There are 500-600 kinds of paper and paperboard produced in China，The main varieties for commodity packaging are box board paper, corrugated base paper, white board paper, yellow board paper, kraft paper, glass cardboard, tar paper, copper paper, rubber paper, coated paper, special paper, glue coated base paper, etc，And the manufacture of corrugated boxes are mainly box board paper and corrugated base paper two kinds。 

　　3. Identification of the front and back sides of paper or cardboard 

No matter what kind of paper or cardboard has a positive and negative points, when making paper, the wet paper web and the net contact surface is the reverse side, the other side is positive。On the opposite side, due to contact with the copper mesh, the loss of fine fibers and fillers is more, showing the screen print, so the reverse side is more rough。The front side is relatively close, and the nature of the front side and the back side are obviously different。The smoothness of the front is higher than that of the back, and the drawing speed of the back is larger than that of the front.The opposite side of the white dot is better than the front, so paper and cardboard have two sides。 

Two sides have a great impact on the quality of printing。Usually, the smoothness and sizing of the front are good, so its printing performance is good。The face paper of the carton must be made so that the front side of the paper faces out for printing and moisture-proof treatment, so that the front and back sides of the paper or cardboard must be identified。 

For the hanging board, the color of the pulp is better than the color of the pulp, the front and back sides are the most easy to identify, some paper or cardboard is made with a multi-cylinder paper machine, or after calender calender, the difference between the surface is not so obvious, at this time can be identified by the following methods: 

1. Direct observation method。Fold the paper or cardboard and observe the surface shape structure on both sides。If there is a paper machine screen printing, the screen printing surface is on the reverse side, when it is not clear to the naked eye, it can be measured by a magnifying glass or a smoothing instrument。 

2, with carbon paper paper observation method。The carbon paper is pressed on the paper, and then the paper is observed to make a mark on the paper, so that the trace of the carbon paper is pressed on the paper, which can be traced to a black trace of about 13㎜ wide and 51-76㎜ long. When observed, it can be placed on a smooth surface glass, identified by 1 method。 

3, use the coin method (aluminum) to mark。Fold the paper, so that both sides are placed on a plane, scratch a mark on both sides with a coin, and then observe the depth of the two marks, the shallow side of the mark is the opposite, which is due to the low amount of filler on the net, the scratch is not easy to show。 

4. Longitudinal and horizontal identification of paper or cardboard 

Paper and cardboard by screen printing molding will have a certain directivity, generally parallel to the direction of cardboard for the vertical, and the direction of the vertical for the horizontal。 

Vertical and horizontal directions can usually be identified in the following ways。 

1. Visual method。Some flat paper can be distinguished with a little attention, it is more obvious to see the light, and the direction of the fiber arrangement is longitudinal。The length direction of the web is longitudinal。 

2. Tear method。If the visual method is difficult to determine the vertical and horizontal direction, you can tear the cardboard by hand, if the tear is straight and smooth, it is longitudinal;If the tear is oblique or zigzag, or even the layer of paper torn at the tear, it is horizontal。Or according to the strip, paper to distinguish, tensile strength is the longitudinal。 

3, tensile instrument measurement method: the use of special tensile testing machine for the test value of the large for the longitudinal value of the small for the horizontal。 

Five, corrugated base paper 

Compared with foreign countries, the corrugated base paper used in China at this stage is generally high quantitative, while the amount of low quantitative and high strength corrugated base paper is still very small。At present, there are not many low-quantitative high-strength corrugated base paper projects planned for new expansion, and the production capacity of new projects is not large, but the demand growth is obvious。With the increasing requirements of users for product quality, the existing corrugated base paper supply system based on middle and low grade products will certainly not meet the demand。Even if the current planned project is put into production on time, by 2005, there will be at least a gap of more than 1 million tons of high-strength corrugated base paper, so low-quantitative high-strength corrugated base paper has to rely heavily on imports。 

With China's entry into WTO, the export of products will be further expanded。According to the preliminary budget, China's main export products, such as clothing textiles, machinery products, agricultural products, etc., will have a significant growth, is expected to increase exports 8 billion to 10 billion US dollars per year。The increase in product exports will inevitably lead to a substantial increase in the corresponding product packaging, and the problem of insufficient supply of domestic high-strength corrugated base paper will be more prominent。 

The reasons for this situation are mainly the following three aspects: First, due to the low added value of corrugated base paper for a long time，Domestic papermaking enterprises that produce packaging paperboard are generally optimistic about products with high added value and high demand such as cow leather box board paper and whiteboard paper，As a result, there are not many low-quantity high-strength corrugated base paper projects planned for new expansion;The second is the improvement of the packaging level of domestic paper products，Rapidly pull the domestic high strength corrugated base paper and cow leather box board paper demand growth，Resulting in domestic high strength corrugated base paper in short supply;Third, the international market for corrugated base paper continues to weaken，Supply exceeds demand，However, China's high strength corrugated base paper market is in short supply，Make foreign manufacturers optimistic about our market one after another。 

From the perspective of market demand, it is a general trend for corrugated base paper to develop in the direction of low quantity, high strength and full specification。现已能生产90 ～115g/m<2的瓦楞原纸，预计将来还会生产60～90g/m2的瓦楞原纸。Due to the large demand for medium strength and high strength corrugated base paper, the price of corrugated base paper will rise。At present, reducing cost and reducing quantity are the two major themes in the development of corrugated base paper。

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