Pulp molding raw materials: In the early years, pulp molding products generally used waste paper as the base material, and used special equipment and molds to perform three-dimensional modeling through a unique process to produce packaging products and objects of various shapes. Pulp molded products start from being used in transportation packages of agricultural and sideline products such as eggs and fruits, and gradually expand the scope of application research. At present, high-quality paper-plastic products using reeds, straw husks, sugarcane, wheat straw, bamboo, wood, etc. as raw materials are more and more widely used, and there are protective packaging for industrial products, such as: electronic products, household appliances, meters, glass and ceramic products , Small machinery, etc. There are also retail packaging of high-quality paper and plastic products in the consumer-resistant category. Pulp molding mainly uses cheap, renewable and recyclable fiber-like natural materials as raw materials to produce high-value environmentally friendly packaging products. Its appearance greatly reduces the environmental pollution caused by the use of foamed plastics. , And opened up a new broad road for the recycling of waste paper.
Production process of pulp molded paper tray products
1. Pulping → pulping → pulping process
Reeds, straw husks, sugarcane, wheat straw, bamboo, wood, recycled paper are used as raw materials. After pulping, refining and other processes, they are turned into fibers and suspended in water to form puree. According to the characteristics of the product, it can be used in A series of auxiliary operations such as controlling the length of the original pulp fiber, the concentration of the original pulp, adding functional additives (brightening agents, waterproofing agents, etc.), dyes and other auxiliary operations in the pulping → pulping → pulping process can meet the production requirements. The required pulping.
Equipment used: pulper, slurry tank, slurry tank, etc.
2. Molding process
The forming process of pulp molded products is mainly through a series of methods such as vacuum forming method and grouting method, so that the raw pulp fiber is formed into the shape designed by the mold; the vacuum forming method is a commonly used and highly efficient method.
Equipment used: forming machine
3. Drying process
The drying process is mainly that the dryer uses fuel, oil, gas, electricity or steam, heat transfer oil or other media as the heat source, heats the air, and dries the molded pulp molded products in hot air, and uses a fan to draw out the product to evaporate. Moisture, to achieve the effect of rapid drying.
Equipment used: dryer (heating method: gas, oil, steam, electric heating
4. Shaping and trimming process
After the pulp product is shaped and dried, it has been basically shaped, and then the heating plate is heated by electric heating or other heat medium (such as heat transfer oil) to make the pulp product mold have a higher temperature (150~250 ℃), using air pressure Or hydraulic pressure, press the paper support product under high temperature and high pressure to make it neat and beautiful in appearance, achieve better toughness, and have better shockproof performance.
Equipment used: shaping, trimming machine
5. Packing
The products produced through a series of processes are inspected, packaged, and put into storage. According to the characteristics of different products, manual packing or automatic packing machine can be used for counting and packing.
Equipment used: automatic packing machine
Process flow chart of molded pulp products
Pulp molded products have the following characteristics
1. It can produce products with various specifications and complex shapes through molds, so that it can meet the packaging needs of products with various shapes, facilitate isolation and positioning, and prevent collisions.
2. The paper is light and soft, and the overall structure has suitable strength and rigidity, which makes it have good protection and cushioning properties.
3. It has ideal ventilation and moisture absorption, which is conducive to the preservation of food. As long as an appropriate amount of waterproofing agent is added to the slurry, the paper molded product can achieve good water resistance; for example, egg trays and fruit trays can be filled with water not higher than 35 ℃ within 24 hours without water marks on the reverse side; but generally The inner packaging of industrial products does not need to have this performance, because waterproofing should be a requirement for storage, transportation, and outer packaging.
4 According to needs, pulp molded products can be flame-retardant, anti-static, waterproof, laminating, printing, and applied to terminal retail packaging.
5. In terms of protective packaging, pulp molded parts have many advantages over EPS, EPE, and EPP cushioning parts:
A. The raw materials of molded pulp packaging products are waste paper and various fiber materials, which have a wide range of sources and are easy to collect, which will not cause obstacles to the environment and recycling, and are beneficial to product exports. However, foamed plastics are derived from petroleum products, and resource depletion and price problems will become more and more serious.
B. Pulp molded packaging products have a wide range of applications. The products currently using foam as lining can basically be replaced by pulp molded products. Pulp molded products can be stacked in stacks, which occupies 1/2~2/5 less storage space than foamed plastics, and the freight and storage costs are smaller.
C. Paper products have good anti-static properties, and the friction of foamed plastics is prone to generate static electricity, which has a better protective effect on electronic products and home appliances.
D. When the plastic products are packaged, the water content of the food is not easy to volatilize, and is easy to mold and rot, while the paper products have water vapor permeability, so as to achieve the anti-corrosion effect.
E. At present, paper molded products are already cheaper than foam plastics in terms of specific packaging costs.
6. The raw materials are extensive and can be used as wastes. The social benefits are obvious. The recycling and reuse rate of products is high. No matter the waste products in production or the finished products after use, they can be used as raw materials for re-production.
The status quo of the development of molded pulp paper trays: The market for molded pulp packaging materials is quite mature. At present, China has formed three pulp molding technology development centers in the Pearl River Delta, the Yangtze River Delta, and Beijing, Tianjin, and Dalian. The application of paper mold package products has spread to all major brand products. Especially since 2001, related companies have increased at an annual rate of 20%. At present, the development level of domestic pulp molding technology is close to that of foreign countries. Many domestic pulp molding manufacturers can independently develop corresponding equipment, special processes, and auxiliary materials to produce mid-to-high-end paper-plastic packaging products.