Wet Press Molded Pulp Production Process

Table of Contents

1. The pulping

Pulp molding wet pressing process is mainly used to produce high accuracy food tableware and industrial packaging products. Its raw materials are mainly commercial sauce board, mainly wooden, sugarcane fiber, bamboo fiber and so on. Its pulp industrial park is the same as the traditional pulp forming production process, including pulp and pulping two processes. Pulp raw materials into the hydraulic mill, through the hydraulic mill will split the raw pulp into fiber pulp, screening the broken fiber pulp, sand removal and other purification treatment, and then through the grinder will be appropriate to make the fiber spray broom, improve the binding force between fibers. The formula is to add fillers, pigments, waterproof and oil-proof and other functional additives to the purified and processed pulp, as the pulp that meets the quality requirements of the product to adjust the pulp concentration. In order to ensure the uniformity of the product, the storage pool and the liquid level height in the pool are well controlled, and fillers, materials and water are added regularly and quantitatively.

2. Forming Process

There are two main molding methods in pulp molding production process: vacuum molding and extrusion molding. The vacuum forming method is commonly used. The basic principle of vacuum forming is to pump the vacuum in the inner cavity of the filter mold with precipitation in the paper slurry, and keep it under negative pressure for a certain time. The fibers in the pulp will be adsorbed on the outer surface of the lower type, and the moisture will be absorbed to form a wet paper mold. The basic principle of extrusion molding is that there is an appropriate amount of pulp in the inner cavity of the lower mold with a filter mold. Under the pressure of pressing or compressed air, after a period of time, the fiber of the pulp will press the inner surface of the lower mold, and the moisture will be extruded to form a wet paper mold.

3. The dry process

In the process of pulp molding production, the dry way of wet paper blank is heating and drying directly in the mold. That is to say, in the cold pressing stage, after the semi-wet paper blank is extruded and dehydrated, the product is hot pressed and dried directly in the pressure mould. When DRYING, THE drying process conditions (such as die pressure, heating time, temperature, etc.) should be adjusted according to the conditions of the paper mold products to ensure the quality of the paper mold products after drying. The density, stiffness and strength of the paper molded products dried in this way are dryness, which is superior to the drying method, and some dried products no longer need shaping and trimming.

4. Stereotypes

The wet paper blank produced by the traditional process will have different degrees of deformation after drying or drying, and the surface of the paper mold product also has different degrees of wrinkles, so it is necessary to form the paper mold product after drying. Water purification The paper mold product is placed on the water purifier equipped with the shaping mold. The high temperature (usually 100 ~ 250) and high pressure (usually 10~20MN) of the water purifier are used to treat the paper mold product with a more regular shape and a smoother surface. Wet press production process is the wet paper mold after forming directly into the hot press drying mold for hot press drying and shaping. Therefore, in order to ensure that the paper mold products fully dry and set, the hot pressing time is generally more than 1 minute (the specific hot pressing time depends on the thickness of the product).

5. Trim the edges

After the above steps of the product, there are irregular edges or debris phenomenon. Therefore, to cut part of the high quality requirements or structural requirements of a part of the product, but also into the edge cutting procedure. The cutting is done on a cutting machine equipped with a product knife mould. Part of the wet pressing process production line is equipped with a supporting cutting machine, the paper mold products after cutting edge output finished products.

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