What are the differences between pure paper and offset paper?

Offset paper is mainly single-sided offset printing paper. The paper surface is white and smooth, but the whiteness, tightness and smoothness are lower than that of coated paper. It is also somewhat different from pure paper. The following is the difference between pure paper and offset paper that I have compiled for you. I hope you like it.

The difference between offset paper and pure paper

Offset paper was formerly known as "Dowling paper" and is mainly used for lithographic (offset) printing machines or other printing machines to print higher-end color prints. , suitable for printing single-color or multi-color book and magazine covers, text, inserts, pictorials, maps, posters, color trademarks and various packaging materials.

Offset paper is divided into special number, No. 1, No. 2, and No. 3 according to the ratio of paper pulp. It has high strength and printability. There are single-sided and double-sided, and there are two levels of super calendering and ordinary calendering. Offset printing is a relatively high-end printing paper for books and periodicals. It has high requirements on contrast, stretch rate and surface strength. The acidity and alkalinity should also be close to neutral or weakly alkaline so as not to affect the paper used for printing.

Offset paper has small elasticity, uniform ink absorption, good smoothness, tight and opaque texture, good whiteness, and strong water resistance. 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. To prevent dirt from sticking to the back, anti-fouling agents, powder spraying or lining paper are generally used.

Pure paper is made of 100% imported high-quality wood fiber. The product has all the natural characteristics of paper with advanced environmental protection concepts. The paper is ultra-light and ultra-thick, economical and practical. Lightweight paper is beige and solid paper is cream. Its smooth and matte surface makes printing more three-dimensional. Books printed with it have soft paper, mild colors, ultra-low reflectivity and a natural scent that will bring you a new feeling.

The concept of pure paper

Made from 100% imported high-quality wood fiber, the product has all the natural characteristics of paper with advanced environmental protection concepts. The paper is ultra-light and ultra-thick, economical and practical. Lightweight paper is beige and solid paper is cream. Its smooth and matte surface makes printing more three-dimensional. Books printed with it have soft paper, mild colors, ultra-low reflectivity and a natural scent that will bring you a new feeling.

The main methods of paper

You can use a lot of them

Generally, the production of printing paper is divided into two basic processes: pulp and papermaking. Pulping is to use mechanical methods, chemical methods, or a combination of both methods to dissociate plant fiber raw materials into natural pulp or bleached pulp. Papermaking is the process of combining pulp fibers suspended in water through various processes into paper sheets that meet various requirements.

Paper mills generally need to store enough raw materials for 4 to 6 months, so that the raw materials can undergo natural fermentation during storage to facilitate pulping and ensure continuous production of the paper mill. In the material preparation section, raw materials such as reeds, wheat straw and wood are cut into pieces (for the production of chemical pulp) or wood pieces (for the production of groundwood pulp), and then the small pieces of raw materials are placed in the digester, chemical liquid is added, and steam is used for cooking , boil the raw materials into pulp, or send the wood pieces to a wood grinder to grind into pulp, or they can also be cooked to a certain extent and then ground into pulp. The paper pulp is then washed with a large amount of clean water, and coarse flakes, knots, stones and sand in the pulp are removed through screening and purification. According to the requirements of the paper type, bleach is used to bleach the pulp to the required whiteness, and then the pulp is beaten using beating equipment. Then various auxiliary materials such as fillers, gums, and sizing agents to improve paper properties are added to the pulp, and are purified and screened again. Finally, they are sent to the paper machine to undergo wire filtration, press dehydration, drying cylinder drying, and calendering. Take it out and slit, rewind or cut it to produce roll paper and flat paper. If the production is to produce coated printing paper, the middle part needs to be dried or produced into web paper and then subjected to coating processing.

In addition to the above basic processes, it also includes some auxiliary processes, such as the preparation of cooking liquid, the preparation of bleaching liquid, the boiling of rubber materials, and the recovery of chemicals and heat energy in cooking waste liquid and waste gas. .

Paper manufacturing process

1: Cut down trees to make materials

2: Cut to appropriate length

3: Peel off Bark

4: Cut into pieces

5: Cut into thin slices

6: Concentrate the slices and transport them to the paper mill

7: Make pulp with liquid and steam

8: Wash with liquid

9: Remove impurities

10: Bleaching pulp

11: Add potion to the paper pulp

12: Drain the water with a net

13 Place it on the felt to absorb water

14: Dry the water at high temperature

15: Use calendering machine for calendering treatment

16: Make paper rolls.

Main surface properties of paper

① Sizing degree (water resistance): The performance of the paper surface in preventing the penetration and diffusion of ink during writing is very important for writing paper. Use a duck-bill pen dipped in special ink to draw lines on the paper, expressed as the maximum width (mm) of the line that does not spread and does not penetrate. ②Smoothness: Under a certain degree of 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. , expressed in seconds. ③Surface strength: In order to prevent paper linting and pasting, offset printing paper is required to have good surface strength. The number of wax rods that press the paper until the fibers are pulled out can also be expressed by measuring the pulling speed using a printing instrument. Drawing paper and tracing paper are tested for their scratch resistance, which is a test of the bonding strength of the surface tissue of the paper.

In addition to the above properties, there are many special performance testing requirements for other technical papers. Such as the dielectric constant, dielectric strength, and dielectric loss of electrical industrial paper, the burning speed of cigarette paper, the thermal conductivity of insulation paper, the resistance coefficient of filter paper to fluids and the interception coefficient of filter paper, and the Softness, absorbency, etc. are all important performance indicators of quality, and they need to be tested according to prescribed standards to evaluate their performance.