Print Paper Views - Paper Structure

Introduction to printing paper

In the first volume of the “China Paper Yearbook” published in 1987, a catalogue of China's domestic machine paper and board varieties was initially sorted out. A total of 543 paper names were included. According to their main purposes, paper and paperboard can be divided into six categories:

(1) Printing paper and cardboard

(2) Writing, drafting and copying paper and board

(3) Packaging paper and cardboard

(4) Living, sanitary and decorative paper and board

(5) Technical paper and board

(6) Processing paper base paper

Among them, printing paper includes newsprint, offset printing paper, offset printing paper, gravure printing paper, dictionary paper, white cardboard, coated paper, lightweight coated paper, cast coated paper, and the like.

Shenzhen's packaging and printing industry has newsprint, dictionaries, coated paper, cast coated paper, offset printing paper, offset printing and writing paper, writing paper, single-sided writing paper, book cover paper, corrugated paper, cardboard, kraft paper, striped kraft paper, rice Cardboard, white cardboard, single white cardboard, single-coated white cardboard, cast white cardboard, cardboard.

For double powdered paper and single powdered paper, Hong Kong is actually used. The correspondence is:

Powder Paper - Coated Paper Matte Paper - Matte Coated Paper

Double powder paper - double-sided coated paper

Powder paper is one of the more used papers in the printing industry. In Hong Kong, this paper name is almost universally known, but not many people are known in the Mainland.

The English name of the powdered paper is Art Paper, which is a popular name for Palladium. This kind of paper was a kind of coated paper that was first developed by the British in the middle of the 19th century. The white and fine china clay was blended into a paint and evenly brushed on the surface of the base paper (coating one side or both sides) became a high-grade printing paper. Because the process is like a woman's powder on her face, she is called powdered paper. In fact, Art Paper was translated as art paper (literally) in China for 30 years. Because the original paintings in Europe were printed on this type of paper, the printed plates were etched with copper plates.

Therefore, according to the convention of using life, the art paper used for copperplate printing is called copperplate (printing) paper. In printing in mainland China, colleagues in the paper industry call Art Paper copperplate paper instead of powdered paper.

Paper structure

The basic raw material for printing paper is plant fibers. Plant fibers constitute the basic structure of the printed base paper, while plant fibers consist of cellulose, hemicellulose and lignin. The composition of the general plant fibers can determine the merits of paper properties, cellulose content is high, the higher the paper's strength, toughness and elasticity; and lignin makes the paper with color, affect the whiteness of the paper. Therefore, depending on the plant fiber, cotton and hemp fibers become excellent papermaking raw materials.

Papermaking includes two processes of paddle and papermaking.

(1) Pelletizing refers to the removal of non-fibers from the cell walls of plants by means of mechanical or chemical methods or a combination of mechanochemistry, that is, the so-called disintegration of the plant fiber raw materials into a natural paper paddle mainly composed of fibers. Or bleached pulp production process. Paddle method can be divided into three types, namely mechanical method, chemical method, and combination of mechanical and chemical methods. Mechanical paddles are suitable for making newsprint. Chemical paddles are mainly used for high-grade papers such as coated paper.

(2) Papermaking is the further processing of pulp to make it a film-like material production process.

It must be propped first to separate the fiber bundles, which will reduce the length of the fibers and reduce the strength of the paper. Therefore, the propeller time should not be too long.

It can be further applied, sizing and dyed. The packing procedure is to add appropriate amounts of minerals and pigments to the pulp in order to create the physical properties required for paper use. The addition of filler can increase the smoothness of the paper, increase the opacity and whiteness, increase the thickness and weight, improve the paper's ink absorption ability and printability.

There are many types of fillers, clay, asbestos, talc, gypsum, calcium carbonate (CaCO3), zinc sulfide, and magnesium carbonate are commonly used to fill in gaps between fibers.

The gluing process is mainly to make the paper have the ability to resist moisture penetration, and it can enhance the paper's hardness, tenacity, resistance to tension, moisture resistance, improve the paper surface smoothness and reduce the fluffing phenomenon, and also improve the printing adaptability of the paper.

The types of sizing include Rosin, Starch, wax emulsion, and the like.

The purpose of the dyeing program is to improve the tone of the paper or increase the whiteness of the paper. A fluorescent material is also used to convert the UV light irradiated to the paper to white light to increase whiteness.

The last is papermaking. The papermaking process is to add a large amount of water to the prepared pulp, so that the fibers in the pulp are hydrated, and the fibers are distributed on the metal network along with the water flow, which forms the so-called machine direction and transverse direction. The fiber orientation of the (Cross Direction) is then entered into a papermaking machine where the fibers are tightly adhered to the papermaking felt to subtract most of the moisture, and are dried, calendered and the like to become usable paper.
Source: Graphic Arts Perspective