Pulp Molding Wet Processing and Dry Processing

Pulp molding wet processing

The wet pressing refers to the process of injecting the pulp into the forming mold through the pipeline after pulping, adsorbing excess water by vacuum, and forming a wet embryo and immediately transferring it to the hot pressing molding die for rapid extrusion drying. 

Advantages of pulp molding wet processing

TThe environmental protection tableware produced by the wet pressing process has high production efficiency, and is transferred to the final shape immediately after forming, and the production speed is fast, the moisture content of the wet embryo in the wet pressing process is about 65-75%, the moisture content is high, and the vacuum adsorption time is required for a long time. The degradable tableware products produced by the wet pressing process have a smooth and delicate surface, beautiful, the disposable lunch boxes produced by the wet pressing process have thinner wall thickness, higher density and save volume.

Disadvantages of pulp molding wet processing

It is not easy to draft or demold the disposable lunch box products with small slope, the products with small R angle or small slope have a higher breaking rate, the heat energy consumption is large.

process of 2500pcs egg tray production line

Application fields of wet pressing process:

  • High-quality work bags, also known as high-end paper-plastic work bags, are mainly molded products with smooth and beautiful outside formed by wet compression molding. These products are mostly suitable for high-end electronic lining boxes, high-end razor packaging boxes, high-end clothes packaging boxes, glasses boxes, etc. These products require extremely high precision, beautiful appearance, and higher added value than other ordinary wet-pressed products.In order to be more beautiful and improve the added value of the packaged products, such products can also be printed in color to better display the effect of packaging.
  • Food packaging containers, also known as disposable degradable tableware, generally refer to wet-pressed molded products such as plates, bowls, boxes, cake dishes, etc. that hold food, generally made of plant fibers such as wheat straw, sugarcane, etc. Complete, add food-grade waterproof and oil-proof dosage.It can be used in daily catering, hotel dine-in, take-out and delivery, etc. These products require microorganisms and heavy metals to meet food-grade requirements. They are produced in dust-free workshops and have a clean and beautiful appearance.
  • Medical trays, mainly wet-pressed products, are mostly used for the stacking of registered equipment and drugs, etc., and require dust-free workshop production, microorganisms must be controlled in accordance with medical standards, and dust-free vacuum sealing.
  • Recreational toys refer to masks, colored toys, etc., which can be produced by semi-dry pressing and wet pressing. It requires good surface smoothness and can retain the painted dyes well, making the hand feel more delicate and smooth. .
    Pulp molding dry pressing process

Pulp molding dry processing

The dry pressing process means that after pulping, the slurry is injected into the forming mold through a pipeline, and after vacuum adsorption of excess water to form a wet embryo, the moisture of the wet embryo is reduced to about 40% by natural drying or through a special drying channel, and then the process is carried out. The process of shaping and molding, which is mostly used to produce low-grade pulp egg trays, pulp bags and other products.

process of pulping

Advantages of pulp molding dry processing

Less heat consumption and reduced energy consumption, mostly pulp products, waste paper can be recycled, low cost and low price, thicker product thickness, good shock resistance and compression effect, packaging electronic products can prevent static electricity.

Disadvantages of pulp molding dry processing

Dry-pressed products (including semi-dry-pressed) products have rough surfaces and poor aesthetics; thicker walls account for a larger volume.

Dry pressing process application fields

  • Ordinary work bags generally refer to the linings, egg trays, fruit trays and other products of low-end electronic products produced by the yellow pulp dry pressing process.
  • Agricultural packaging, mainly refers to flower pots, seedling cups, egg trays, etc. Most of these products are produced by dry pressing of yellow pulp and newspaper pulp. These products have low requirements for hygiene and product stiffness. Not high, but requires better waterproof performance.
  • Medical packaging, dry pressing is mainly used in places with low requirements such as bedpans, urinals, kidney-shaped trays, etc.