Wet Processing Pulp Molding Technology
Wet processing refers to paper pulp injection into the paper tray mold, use vacuum to remove the extra water, wet paper tray being transferred to hot pressing mold, then it is being pressed and dried.
Advantages of wet processing: high production capacity, after the wet paper tray is formed, it is dried instantly, you can have a high production speed; the wet paper tray contains water at 65-75 percent, this requires a longer vacuum suction time; paper tray produced in wet processing method has smooth surface and better outlook, disposable tableware produced in wet processing method has thin wall thickness, high density to save space.
Disadvantage of wet processing: for paper tray with small slop, it is not easy to demold, small slop and R angle paper tray product has high broken net rate, and consumes more heat.
Wet processing application field:
- High quality paper tray package, mostly uses wet processing to form smooth and better outlook of paper tray product. This type of product is always used as high end electronic curtain box, box for high end razor, clothe, glasses, etc. These product has higher accuracy requirement for outlook and extra value higher than other wet processing paper tray products. In order to add more value to this type of paper tray product, color print is used to show better package info.
- Food container, which is known as disposable tableware, such as disk, bowl, case, cake disk paper tray, etc. Usually it is made of wheat straw, sugar cane, with food grade water and oil repellent dosage added, it will show good water and oil proof.
- Medical paper trays made in wet pressing method, used for put in medical equipment and drugs. They are required to have high standard of cleanness. Microorganisms shall be controlled in medical standards.
- Toys refers to masks and paint-able toys, it can be produced in semi dry processing, and wet processing methods. Requires the outer surface to be smooth so that the paint can be preserved on it in an even state, makes the hand feel more delicate and smooth.
Pulp Molding Dry Processing
Pulp mold dry processing refers to paper pulp being delivered to the mold die, forms wet paper tray after the vacuum sucked out extra water, uses natural drying or special drying tunnel to lower the water content to 40%, then use hot press machine to reshape the paper tray. It is used for production of low end product such as egg tray, industrial package made of paper pulp.
Advantage: Less heat is needed, saves power consumption; mostly paper pulp products, raw material could use waste paper to lower the cost, product thickness is big, has better anti pressure and shacking effect; it has high aesthetics.
Disadvantage: rough surface, no perfect outlook; big thickness requires large space.
Dry processing application field:
- Ordinary Package: usually refers to use paper pulp molding technology to produce low end electronic product curtain, egg tray, apple tray, etc. Features with good anti shock and pressure, has low standard for outlook.
- Agriculture package: refers to flower vase, seedling cup, egg trays, these product uses yellow pulp and newspaper pulp to produce dry process technology products. This type of product has lower standard for hygiene, low hardness, but requires high standard of water proof.
- Medical Package: lower requirements such as bedpans, urinals, and kidney-shaped discs.