Eleven classifications and characteristics of pulp molding
(1) According to the process, it is divided into wet pressing, dry pressing and semi-dry (wet) pressing.
A. Wet pressing is pulp wet embryo molding immediately after transferring into the mold molding (drying in the mold) for rapid extrusion drying.
Advantages: The process has high production efficiency and can be transferred to molding immediately after molding, with fast production speed; the moisture content of wet embryo in the wet pressing process is about 65-75%, which is higher and requires a longer vacuum adsorption time. The surface of the products produced by wet pressing process is smooth, delicate and beautiful. Wet pressed products have thinner wall thickness, higher density and save volume.
Disadvantages: The products with small slope are not easy to stretch or demould; the net crushing rate of products with small angle or slope is higher. It consumes a lot of heat energy.
Wet press pulp molding main product types and application areas: electronic products lined with industrial packaging (such as Dell computer boxes, cell phone liner boxes, razor boxes), a variety of tableware, masks, decorative wall panels, etc., mostly used in the field of higher added value.
B. Dry pressing is done by air drying, hanging basket drying, natural drying, or sunroom, wind, vacuum and other special drying equipment after drying, and then shaping.
Advantages: low cost, high efficiency, good buffering performance.
Disadvantages: surface sensory quality is relatively rough, post-processing such as printing adaptability is poor.
Application areas of dry-pressed pulp molded products: industrial cushioning packaging, egg trays, egg cartons, seedling trays, seedling trays, fruit trays, etc.
C. Semi-dry (wet) pressing is to dry the wet embryo of pulp molding, then use special equipment to rewet to 25% to 45% moisture content, and then use hot mold shaping.
Advantages: the quality of the finished product is between dry pressing and wet pressing, but the efficiency is greatly improved.
Disadvantage: The surface quality is average and not very suitable for post-printing treatment.
Application areas: less demanding outer packaging of gifts and daily necessities, more demanding inner buffer packaging.
(2) Pulp molding is divided into:
Fine work package (such as full pulp molded electronic product outer packaging, cosmetic outer packaging, wine package cigarette package, etc.);
Ordinary work package (such as cushion lining);
Food packaging (tableware, cake trays, dumpling trays, packing boxes, etc.);
Agricultural packaging (flower pots, nursery cups, seedling trays, sand-fixing trays, fruit trays, etc.);
Medical packaging (urinals, kidney-shaped trays, medical urinals, medical needle and thread boxes, vaccine trays, pregnancy test sticks, etc.);
Construction materials (decorative wall panels, etc.);
Pet supplies (cat litter trays, dog and cat food trays, cat houses, etc.);
Furniture supplies (stools, storage boxes, ice buckets, clocks, barbecue boxes, etc.);
Cultural and creative supplies for daily use (pulp molded masks, hats, slippers, masks, toys, etc.);
Pulp molded containers (wine bottles, beverage bottles, etc.);
Others (sprue pipes, parts, balloon holders, toys, etc.)
(3) Pulp molded by raw materials.
Recycled pulp products (yellow pulp, newspaper pulp, etc.), sugar cane pulp products, wheat straw pulp (straw) products, bamboo pulp products, wood pulp products, reed pulp products, palm pulp products, melon and vine pulp products, cotton straw pulp products, etc.
(4) According to the color of raw materials (products): natural color (natural color), white and dyeing.
(5) pulp molding pulp raw materials according to the process is divided into bio-mechanical pulp, mechanical pulp products, semi-chemical mechanical pulp products, chemical mechanical pulp products and chemical pulp products (basically all can be made into pulp board are chemical pulp) and recycled pulp.
(6) Pulp molding can be divided into non-protective products, single-protection products (general waterproof) and double-protection products (waterproof and oil-proof), moisture-proof packaging, anti-static packaging, and high-barrier packaging according to the use of performance.
(7) According to the lamination situation, it is divided into non-laminated products and laminated products (laminated material is PE/PET/CPET/PP/PBAT/PLA, etc.).
(8) According to printing (or dyeing): color printing (can be divided into single-color and multi-color; also can be divided into pad printing and screen printing) and non-printing, printing ink is divided into water-based ink and industrial ink printing, no including the whole product dyeing.
(9) Pulp molding is divided into pulp injection type, pulp fishing type and pulp absorption type according to the molding process.
(10) According to the use of wire mesh, it can be divided into light surface mesh type and double-sided light type.
(11)Pulp molding according to the type of equipment: manual products, semi-automatic machines and fully automatic machines.
