Tissue Machine For Making Toilet Paper

TISSUE MACHINE FOR MAKING TOILET PAPER

1.Definition

A tissue machine for making toilet paper is a piece of industrial equipment.

It typically consists of a number of components. The raw material, usually pulp, is fed into the machine. The machine has a forming section where the pulp is evenly distributed and formed into a continuous sheet through a process such as through a wire mesh or a forming fabric. Then there's a pressing section to remove water from the sheet and make it more solid. After that, it may have a drying unit to further reduce the moisture content. Some advanced machines also have embossing rollers to give the toilet paper a texture and can cut the continuous sheet into appropriate roll lengths and widths to make the final toilet paper rolls. These machines play a crucial role in the large - scale production of toilet paper.

2.Machine Details

The process of making toilet paper from bamboo pulp generally includes the following steps:

Pulp Preparation

- Raw Material Harvesting: Bamboo is harvested and transported to the paper mill. Bamboo is a sustainable resource as it grows relatively fast.

- Pulping: The bamboo is chipped into small pieces. Then, it goes through a chemical or mechanical pulping process. In chemical pulping, chemicals like sodium hydroxide and sodium sulfide are used to break down the lignin (the substance that holds the plant cells together) and separate the cellulose fibers. Mechanical pulping involves grinding the bamboo to separate the fibers. The resulting bamboo pulp is a slurry of fibers and water.

Paper - making Process

- Forming the Web:

- The pulp slurry is pumped into the headbox of the tissue machine. The headbox distributes the slurry evenly across a moving wire mesh or a synthetic forming fabric in a process called wet - laying. As the water drains through the wire, the bamboo fibers start to interlace and form a wet paper web.

- The speed of the wire and the consistency of the pulp flow from the headbox play a crucial role in determining the thickness and uniformity of the web.

- Pressing:

- The wet paper web then moves to the press section. Here, it passes through a series of rollers that apply pressure to squeeze out more water. This step not only reduces the moisture content but also compacts the fibers, giving the paper some initial strength.

- The press nip (the point where the rollers meet) pressure and the number of press nips can vary depending on the desired paper properties.

- Drying:

- After pressing, the paper web enters the drying section. There are two main drying methods in modern tissue - making.

- Conventional Cylinder Drying: The paper passes over a series of heated metal cylinders. Hot air is also blown onto the paper to enhance the drying process. As the paper contacts the hot cylinders, the moisture in it turns into steam and is removed.

- Through - Air - Drying (TAD): In this more advanced method, hot air is forced through the paper web. TAD - produced toilet paper is usually more bulky and softer because the fibers are allowed to fluff up during the drying process. The drying temperature and air velocity are carefully controlled to achieve the desired dryness level (usually around 4 - 6% moisture content for toilet paper).

- Calendering (Optional): Some toilet paper may go through a calendering process. Calendering involves passing the paper through a set of rollers under pressure to give it a smoother surface. However, for some types of toilet paper, a less - calendered, more textured surface is preferred for better absorbency and a softer feel.

Converting Process

- Reeling and Winding: The dried paper is wound onto large parent rolls. The winding tension is carefully controlled to ensure that the roll is tight and uniform.

- Slitting and Rewinding: The large parent rolls are then slit into smaller rolls of the desired width for consumer use. The toilet paper rolls are usually perforated during this stage so that individual sheets can be easily torn off.

- Packaging: The finished toilet paper rolls are packaged, usually in plastic or paper wrappers, and then boxed for distribution to retailers.