Advantages and weaknesses of pulp molding products

Modern packaging generally uses paper, plastic, glass, ceramics, metal as packaging materials, because paper and plastic are cheap and easy to process, and the source of raw materials is wide, so paper and plastic packaging materials are widely used in daily life.

However, because plastic packaging materials can not degrade themselves, it will cause environmental pollution and other problems, and the white pollution problem in China is the most typical example.

With the development of society and the requirements of global economic integration, green packaging has gradually become the consensus of society, and has become another bright spot in the development of China's packaging industry. According to the quantitative evaluation of international authoritative experts, only paper is the most promising green packaging material. In recent years, China's paper molding products equipment has developed very fast, and gradually mature. With the continuous promotion of the application range of pulp molding products, the requirements of paper molding products continue to improve, and the design of pulp molding production process and mold need to be constantly improved and improved.

In this paper, according to the process characteristics of pulp molding products, the present situation of pulp molding products is analyzed, and some elements of mold design of pulp molding products are studied.

First, the process analysis of pulp molding products

1. Process process Under normal circumstances, the production process can be changed according to the different requirements of customers for products, mainly including slurry preparation, molding, hot press setting, setting, molding and packaging and other auxiliary processes.

2. Raw material selection of pulp molded products The sources of pulp molded products are mainly divided into: Pulp, straw pulp and reed pulp, generally bleached commercial pulp (for fast-food boxes) or waste paper (for industrial packaging), will not produce secondary pollution in the production and use process, the product has the advantages of light weight, pressure resistance, earthquake resistance, good buffer performance, anti-static, strong air permeability and good recyclability. As a packaging product, it can replace polystyrene foam (EPS) for disposable fast food boxes, various electronic products, handicrafts, medical devices, mechanical equipment parts, poultry eggs, fruits, flowers, glass products, ceramic products and other fragile products.

Pulp molding products are generally divided into fast food boxes and industrial inner packaging, the production method is basically the same, but the raw materials used for the production of fast food boxes are bleached commercial pulp, quantitative and specification indicators are more strict, and sterilization, waterproof and oil-proof treatment, equipment and pipelines are mostly stainless steel and plastic materials, storage pool wall lined with tiles, The plant and operator health requirements are also higher.

3. Pulping Pulping is the first process in the production of pulp molded products. The pulping process includes: the pulp board is broken into fiber pulp with a hydraulic pulper, the broken fiber pulp is screened, sand removal and purification treatment, and then the fiber is properly spun by the pulper to improve the binding force between the fibers.

In the pulping process, strict control of the beating degree of various slurps is very important for the product molding and product quality of the following process.

The beating degree is too high, when the product is vacuum adsorption molding, it will produce water filtration difficulties, and after drying by the drying channel, the product will produce a large shrinkage deformation (except for mold drying).

If the beating is too low, the combination strength of the product is low, and the stiffness and compressive strength of the product will be greatly reduced, which will affect the performance of the product. Therefore, the corresponding beating degree should be determined according to the selected slurry, the proportion of the slurry, and the amount of beating required.

The equipment used in the pulping process of paper pulp molding products mainly includes hydraulic pulper, fiber desanding machine, cone desander, beater (or pulper) and pulp pool and other general equipment in the paper industry. For relatively simple and small scale production processes, only the use of hydraulic pulper and slurry tank can also meet its general production requirements.

4. Matching pulp is to add fillers, pigments, and functional additives such as waterproof and oil repellent to the purified and treated slurry, and to prepare the slurry suitable for the quality requirements of the product, and sometimes to control the pulp concentration. In order to ensure the continuous production process and the evenness of the product, it is necessary to control the liquid level height in the slurry storage tank and the slurry distribution tank, and to add fillers, water and ingredients regularly and quantitatively.

Pulp molding products according to the requirements of enterprises can choose to add waterproof, oil-proof and other functional additives.