The popularization of technical knowledge of paper making

The source of paper raw materials

The raw materials of modern paper are mainly from plant fibers, including wood, waste paper, bamboo and so on. Among them, wood pulp is one of the most widely used papermaking raw materials, which can be made of wood from various trees through chemical or mechanical processing. Waste paper refers to the paper that has been used, which can reduce the consumption of natural resources through recycling, and is an environmentally friendly papermaking raw material. Bamboo is a fast growing plant with a unique fiber structure and is also widely used in the production of paper. 

Paper production process

The production process of modern paper usually includes four main links: slurry preparation, paper molding, drying and processing. First of all, the prepared pulp is added to the paper forming machine, after a series of extrusion and filtration operations to form wet paper, and then the wet paper is dried and pressed, and finally the finished paper is obtained. This is followed by subsequent processes such as cutting, packaging and storage of the finished paper for subsequent sale and use. 

Paper forming technology

Paper forming technology mainly includes wet method and dry method. Wet forming means that pulp is added directly to the forming machine to form wet paper, which is then dried and pressed. Dry molding is to form wet paper on the mesh strip by spraying and pressing the pulp, and then dry and press the wet paper. Different forming techniques will affect the quality, thickness and surface effect of the paper.

The process of producing toilet paper from wood:

The detailed process of wood production of toilet paper can be summarized in the following main steps, each of which contains specific operational and technical points:

1 、Raw material selection and preparation

1)         Choose wood:

The main selection of natural forest wood, such as fir, poplar, birch, pine and so on, these woods have different fiber characteristics, suitable for the production of different types of toilet paper.

Wood requires a certain hardness and stability, the diameter is usually more than 8 cm, to ensure the smooth progress of the processing process and the quality of the finished product.

The moisture content of wood should be controlled below 20% to avoid drying deformation or quality problems.

2） Peeling and cutting:

The harvested trees are peeled to remove bark and impurities.

Use a chipper to cut the peeled log into short pieces for easy subsequent processing.

2、the pulping process

1)         Soaking and cooking:

Put the cut wood chips in a digester, mix with alkaline solution and white solution, and cook at high temperature. The purpose of this step is to dissolve the lignin and separate out the cellulose fibers.

During cooking, nearly half of the wood dissolves, forming a cellulose slurry.

2)         Washing, screening and bleaching:

Wash the cooked cellulose fibers to remove any remaining chemicals and impurities.

Pure cellulose fibers are further separated by screening equipment.

The cellulose fibers are bleached as needed to improve the whiteness and appearance of the toilet paper.

3、 the papermaking process

1)         Molding and dehydration:

The cellulose slurry is evenly sprayed onto the mesh of the paper machine, through a process of extrusion and dehydration, so that the fibers form a wet paper on the mesh.

During this process, control the ratio of fibers (such as 3:7 or 4:6 for long and short fibers) to obtain soft, absorbent, and unbreakable toilet paper.

2)          Drying and wrinkling:

The wet paper is dried in the dryer at a high temperature (up to 450°C), so that the water gradually evaporates to form the finished paper.

The drying process also creases, using a scraper to break the bond between the fibers, making the paper more elastic, thicker, absorbent and softer.

4、 processing and cutting

1)       Multi-layer winding:

Roll several large rolls of paper together into multiple layers of finished toilet paper (usually three or four layers) to improve the thickness and strength of the paper.

2)       Cutting and packaging:

Cut the wound toilet paper to form a roll or bag that meets the specifications.

Package the cut toilet paper, such as using plastic film or carton, to protect the toilet paper from contamination and damage.

5、 Additional Processing (optional)

Depending on market demand and specific brand requirements, toilet paper may undergo additional treatment, such as adding softener, bleach, fragrance or color printing.

6、Sum up

The process of wood production of toilet paper includes raw material selection and preparation, pulping process, papermaking process, processing and cutting, and additional treatment (optional). Each link requires strict control of quality and technical parameters to ensure that the final produced toilet paper is soft, absorbent, non-irritating and easily soluble in water. At the same time, with the improvement of environmental awareness and technological progress, the production process of toilet paper is also constantly optimized and improved.

The process of producing toilet paper from waste paper:

The detailed process of producing toilet paper from waste paper can be summarized into the following main steps, each of which contains specific operational and technical points:

1、 Waste paper recycling and treatment

1)         Waste paper collection:

Collect waste paper from a variety of sources, including home, office, printing plant, etc.

2)         Waste paper classification:

Sorts the collected waste paper to remove impurities such as plastic, metal, glass, etc.

3)         Crushing and cleaning:

Use a crusher to break the waste paper into smaller pieces for subsequent processing.

Clean the broken waste paper to remove dust, oil and other pollutants on the surface.

2、 The pulping process

1)       Hydraulic crushing:

The cleaned waste paper fragments are sent to the hydraulic pulper for beating and deinking. The hydraulic pulper will hydraulically break up scrap paper and remove ink and other impurities from it.

2)       Screening and removing impurities:

The beaten pulp is sifted through a high-frequency vibrating screen to remove large particles and unbroken impurities.

3)       Bleaching and bleaching:

Feed the screened pulp into the rinsing machine for further cleaning to remove residual ink and impurities.

Bleach the pulp as needed to improve the whiteness and appearance of the toilet paper. Chemicals such as sodium hypochlorite are used in the bleaching process.

4)       Grinding and impurity removal:

The bleached pulp is sent to the pulp mill for fine grinding to make the pulp more fine and even.

Use the sand settling table and other equipment to separate the sediment of sand and ash in the pulp and make the pure pulp.

3、The papermaking process

1)       Pulp preparation:

Add appropriate amount of water and chemicals to the pure pulp to form a stable and uniform pulp.

2)       Paper machine forming:

Feed the prepared pulp into the paper machine, and the paper machine will evenly spread the pulp on the mesh belt.

By the action of a series of rollers and pressure rollers, the paper pulp is formed on the net cloth with a certain thickness and uniformity of the web.

3)       Pressing and drying:

The formed web is pressed to improve its tightness and strength.

The pressed web is sent to the dryer for high temperature drying to remove moisture and form dry toilet paper.

4、Processing and packaging

1)       Rewinding and punching embossing:

Rewind the large roll of dried toilet paper and roll it into small rolls.

Hole punching and embossing are performed during the rewinding process to make it easier for consumers to use and tear toilet paper.

2)       Cutting and packaging:

Send the rewound small roll of toilet paper to the slitting machine for slitting to form the specifications and sizes that meet the market demand.

Package the cut toilet paper, such as using plastic films, cartons, etc., to protect the toilet paper from contamination and damage.

5、Quality control and environmental protection measures

In the whole production process, it is necessary to strictly control the quality and technical parameters of each link to ensure that the produced toilet paper meets the national standards and market demand.

At the same time, necessary environmental protection measures should be taken, such as the use of environmentally friendly chemicals, the reduction of wastewater discharge, the recycling of waste, etc., in order to reduce the impact on the environment. 

Through the above steps, waste paper can be effectively converted into high-quality toilet paper products, to achieve the goal of recycling resources and reducing environmental pollution.

Bamboo production process of cultural paper:

The detailed process of bamboo culture paper production can be summarized in the following main steps, each of which contains specific operational and technical points:

1、Raw material preparation

1)       Bamboo cutting and selection

After the bamboo is formed, it is regularly cut down and selected for paper making. Bamboo should be selected to grow well, free of pests and diseases, fiber rich varieties.

The felled bamboo should be pruned to remove the branches, leaves and excess parts, so as to facilitate subsequent processing and transportation.

2)       Soak and soften bamboo

Cut the pruned bamboo into lengths (such as 5 to 7 feet or 5 '5 ") and soak in a pond or lime basin. The soaking time is usually about 100 days to soften the bamboo and remove some impurities.

The soaking process, during which bamboo gradually rots and breaks down its fibers, is the longest part of the papermaking process.

2、The pulping process

1)       Bamboo crushing and cooking

Remove the soaked bamboo and wash it to remove lime and impurities. A crusher is then used to break the bamboo into smaller pieces.

Mix the broken bamboo mixture into lime water or other alkaline solution and cook in a digester. Cooking time depends on the specific situation, usually takes a few days to more than ten days. During the cooking process, impurities such as lignin, gum and resin in bamboo are removed, and the fibers are gradually decomposed.

2)       Washing and screening

l  The cooked bamboo is washed to remove any remaining chemicals and impurities.

Use the screening equipment to screen the washed bamboo pulp, remove large particles and undispersed impurities, and obtain pure bamboo fiber.

3、The papermaking process

1)       Pulp preparation and molding

Add appropriate amount of water and chemicals to the screened bamboo fiber for blending to form a stable and uniform pulp.

Feed the prepared pulp to the paper machine and spread the pulp evenly on the mesh belt through the forming department of the paper machine. Under the action of the mesh tape, the water in the pulp is gradually discharged, and the fibers are interwoven together to form a paper web.

2)       Press and dry

The resulting web is pressed to further remove moisture and improve the tightness and strength of the paper.

The pressed web is sent to the dryer for high temperature drying. The hot air in the dryer will cause the moisture in the paper to evaporate quickly, forming dry paper.

4、follow-up processing and packaging

1)       Cutting and finishing

The dried paper is sent to the slitting machine for slitting treatment to form the specifications and sizes that meet the market demand.

Finish the cut paper to remove rough edges and uneven parts to make it more beautiful and neat.

2)       Packaging and storage

Pack the finished paper, such as using plastic films, cartons, etc., to protect the paper from contamination and damage.

Store the packed paper in a dry, ventilated warehouse for sale and use.

5、Quality control and environmental protection measures

In the whole production process, it is necessary to strictly control the quality and technical parameters of each link to ensure that the produced cultural paper meets the national standards and market demand.

Take necessary environmental measures, such as the use of environmentally friendly chemicals, reducing wastewater discharge, recycling waste, etc., to reduce the impact on the environment. 

Through the above steps, bamboo can be effectively converted into high-quality cultural paper products to meet people's writing, printing and other needs.

The process of producing kraft paper from wheatgrass:

The detailed process of wheat grass production of kraft paper can be summarized into the following main steps, each step contains specific operational and technical points:

1、Raw material preparation

1)       Wheat grass collection and cleaning

Collect mature wheatgrass as raw materials and carry out preliminary cleaning to remove weeds, dirt and other impurities.

2)       Crushing treatment

Use a crusher to break the cleaned wheatgrass into smaller pieces to facilitate the subsequent pulping process.

2、The pulping process

1)       Chemical pretreatment

Chemical pretreatment, such as NaOH, H₂O₂ and other chemical agents are used to treat the broken wheat straw to improve the pulp performance and reduce the lignin content. This step may include specific operations such as pre-steaming and chemical soaking.

2)       Pulping

The pre-treated wheat straw is fed into a pulping plant where it is further broken and converted into pulp by mechanical or chemical means. During the pulping process, the fibers of wheatgrass are fully dispersed and refined.

3)       Heat, stir and sift

Heat and stir the pulped pulp to improve its uniformity and fluidity. Then the large particles and impurities in the pulp are removed through the process of coarse screening and fine screening to ensure the purity of the pulp.

4)       Bleach

Bleach the pulp as needed to improve its whiteness. Chemicals such as sodium hypochlorite are used in the bleaching process to remove pigments and residual lignin from the pulp.

3、The papermaking process

1)       Pulp preparation

Mix the bleached wheatgrass pulp with other raw materials (such as waste pulp, bamboo and wood pulp, etc.) in a certain proportion, and add appropriate amount of water and chemical additives to make the pulp suitable for paper making.

2)       Paper machine molding

Feed the prepared pulp into the paper machine and spread the pulp evenly on the forming net by the action of the mesh band or long mesh part. Under the tension of the mesh and the gravity of the pulp itself, the water is gradually discharged, and the fibers are interwoven to form a paper web.

3)       Press and dry

Press the resulting web to remove more moisture and improve the compactness and strength of the paper. Then the pressed web is sent to the dryer for high temperature drying treatment, so that it meets the specified moisture content and strength requirements.

4、Follow-up processing and packaging

1)       Coiling and cutting

Roll the dried paper from the paper machine and cut it as required to form a size and specification that meets the market demand.

2)       Calender and finish

Calendering of cut paper to improve surface finish and smoothness. It is then finished to remove rough edges and uneven parts to make the paper more beautiful and tidy.

3)       Packaging and storage

Packaging the finished paper such as using plastic films, cartons, etc. to protect the paper from contamination and damage. Store the packaged paper in a dry, ventilated warehouse for sale and use.

5、Quality control and environmental protection measures

In the whole production process, it is necessary to strictly control the quality and technical parameters of each link to ensure that the produced kraft paper meets the national standards and market demand.

Take the necessary environmental measures such as the use of environmentally friendly chemicals, reduce wastewater discharge, recycling waste to reduce the impact on the environment. 

Through the above steps, wheatgrass can be effectively converted into high-quality kraft paper products to meet the needs of packaging, printing and other fields.