Pulping process

1. Saw wood

Logs must be sawn to length to meet the requirements of subsequent sections. The chipper requires a log length of 2-2.5m, and the wood grinder requires a log length of 0.6-1.2m.

2. Peel

Due to the low fiber content of the bark and the high paper content, the cooking efficiency will be reduced, the consumption of cooking chemicals will be increased, the dust in the pulp will increase, and the strength will decrease. Therefore, when producing pulp with higher quality requirements, it is generally required to remove the outer skin.

3. Departure

In order to avoid the influence of tree knots on the quality of magic stone and wood pulp when wood segments are ground, the wood segments sent to the wood grinder also need to remove tree knots.

4. Chipping

In order to adapt to chemical wood pulp cooking and meet the production needs of wood chip grinding wood pulp, the logs are chipped. The wood chips cut out should be consistent in length, thickness, and thickness. The wood chips are generally 15-20mm long, 3-5mm thick, and not more than 20mm wide.

5. Pulping

It refers to the production process of dissociating plant fiber raw materials into unbleached pulp (unbleached pulp) or further bleaching into bleached pulp by chemical methods or mechanical methods or a combination of the two methods.

6. Washing

The purpose of washing is to fully wash the pulp. Crude fiber bundles, groundwood pulp also contains thick wood strands, large wood chips and crude fiber bundles. In addition, in the process of raw material collection, transportation, storage and production, sediment, fly ash, iron wire, and plastic stool debris will also enter. These substances not only affect the quality of the finished paper, but also damage the machinery and equipment, so that the production cannot be carried out smoothly. Therefore, the above impurities must be removed by screening and purification.

7. Bleaching

The main purpose of the bleaching process is to remove the colored substances in the fibers and obtain pulp with a certain brightness and suitable physical and chemical properties.

modulation process

The preparation of paper stock is another key point of papermaking. The strength, color tone, printability of the paper after completion, and the length of the paper shelf life are directly related to it. The common modulation process can be roughly divided into the following three steps: 1. Slurry; 2. Beating; 3. Gluing and filling.

Copying process

The main work of the papermaking department is to uniformly interweave and dehydrate thin paper materials, and then go through drying, calendering, rolling, cutting, sorting, and packaging. Therefore, the common processes are as follows:

1. Screening of paper stock

Dilute the prepared paper stock to a lower concentration, and use the screening equipment to screen out impurities and undissociated fiber bundles again to maintain the quality and protect the equipment.

2. Net Department

Make the paper material flow out from the head box on the circulating copper wire mesh or plastic mesh and evenly distribute and interweave.

3. Press section

The wet paper that has been removed from the mesh surface is led to a space between two rollers attached to a felt, and the pressing of the rollers and the water absorption of the felt can further dehydrate the wet paper and make the paper tighter, so as to improve the quality of the paper. On paper, increase the strength.

4. Dryer

Since the moisture content of the wet paper after pressing is still as high as 52-70%, it is no longer possible to use mechanical force to remove the moisture. Therefore, the wet paper is changed to pass through many cylindrical surfaces with heated steam to dry the paper. .

5. Roll paper

The paper web is wound into a roll by a reel.

6. Cutting, sorting and packaging

Take several rolls of paper that have been rolled into a tube, use a paper cutter to cut into sheets, and then manually or mechanically sort out the damaged or stained papers, and finally wrap each 500 sheets into a pack (often called an order).