Pulp Molding Packaging Waterproof Technology

In the process of managing “white pollution”, pulp molded products for industrial packaging have developed rapidly. According to statistics in 1997, China’s paper products for industrial packaging accounted for only about 1% of the total packaging supplies, while Western developed countries accounted for about 15% of the total.

In China, there is a great development in the packaging of industrial products with paper, wood, and lining packaging. The types of Pulp paper packaging products mainly include recycled paperboard as the base material, honeycomb paperboard tray series and honeycomb cardboard packaging box series produced by modern electromechanical unity equipment, which are used to replace wood pallets and wood packaging boxes; A newspaper or the like is used as a raw material, and a paper mold lining product produced by a pulp molding machine is used instead of a foamed plastic product. However, these paper packaging products, especially the paper mold lining packaging products, are weaker than the plastic blister packaging products. In the sea and humid environment, the paper molding products are easy to absorb moisture and the strength is lowered. Therefore, it is necessary to solve the problem of reinforcement and waterproofing of paper packaging products.
There are four main factors affecting the strength of paper-wrapped products:
1 fiber strength itself;
2 bonding strength between fibers and fibers;
3 fiber bonded surface area;
5 distribution of bond.
For the above four factors, the solutions are:
First, in the pulping process, the medium-concentration long fiber is used in the form of sticky beating. Medium-concentration beating refers to a kind of beating method carried out in medium-concentration beating equipment under the condition of beating concentration of 4-6%. The long-fiber viscose beating method requires that the fiber should be cut as much as possible to keep the fiber at a certain length. And a high degree of silk fibrillation, a kind of beating method with good swelling and hydration. The advantages of this beating method are:
1The fiber is cut less, the distortion is more, and the finished product has good strength;
2 When the strength of the paper products is the same, the pulping degree and the water retention value are low, and the dewatering performance is good;
3 The beating time is shortened, the energy consumption is reduced, the performance of the equipment is improved, and the product cost is reduced. Medium-concentration beating can reduce the concentration of concentration and dilution, so that electric energy can save 20-30kw ht dry pulp.
Second, after the pulp is dissolved. At present, most manufacturers only have a beating process without a pulping and resolving process, which makes the finished fiber lack the condition for increasing the strength portion. Although the time of passing the paper material through the disintegrator is only a few seconds, the pulp crushed by the hydraulic pulper is cut, split and finely fiberized by the disintegrator, which can make the paper product evenly distributed and increase the finished product. strength.
Third, adding a reinforcing agent to increase the strength of the product; adding a waterproofing agent to increase the waterproof and moisture-proof properties of the product.
There are two methods for enhancing the chemical additives of paper products, one is an internal reinforcing agent and the other is a surface reinforcing agent. The internal reinforcing agent is further divided into a dry reinforcing agent and a wet reinforcing agent.
Dry reinforcing agents are generally used as reinforcing agents for increasing the packaging of industrial products for pulp molding. Dry enhancers are fine chemicals used to enhance the bond between fibers to increase the physical strength of the paper product without affecting its wet strength. Such a chemical has a reactive group of a certain molecular weight, and since the bonding strength of its own colloidal molecule can form a hydrogen bond with the hydroxyl group of the cellulose, the enhanced requirement of the paper product can be achieved.
Commonly used dry enhancer varieties are: cationic starch, anionic starch, amphoteric starch, multi-component starch and ionic polyacrylamide.
Cationic starch and multi-component starch (including amphoteric starch) are both good retention aids and good dry enhancers. Its enhancement principle is mainly attached to the surface of the fiber by the electrostatic attraction between the cationic group in the starch and the negative charge on the surface of the fiber, and is adsorbed by the bridging of the hydrogen bond with the fiber, so that the networked rubber is formed between the deuterated fibers. The whole of the joint, in order to achieve the purpose of improving the strength of paper products.
Application of starch as a reinforcing agent, the amount is generally 1-2% of the dry pulp material, the starch without gelatinization can not be directly added to the pulp pool, the starch must be pasted and processed into a starch paste liquid (no gelatinization conditions can be used) Can be used after purchasing dextrin. The method of gelatinization is:
1 In the gelatinization tank, first add a certain volume of soft water or clean cold water with low hardness, start the stirrer (stirring speed is 60-100 rpm), then slowly add starch to fully disperse the starch. Generally, the gelatinization concentration is 5%, and then the steam is directly heated, but the vapor pressure cannot be opened too high to prevent the high temperature steam from degrading the starch. It is better to use the inter-connected steam to heat. While continuing to stir, the temperature was raised to 90-95 ° C to make it into a gelatinization solution, and it was kept at this temperature for about 20 minutes. This step is critical, and attention should be paid to starch that is incompletely gelatinized, as the starch particles are not sufficiently dispersed to affect the effect of use. However, the holding time should not be too long, and the temperature should not be too high to prevent the degradation of starch under high temperature for a long time.
2 The starch paste after gelatinization should be diluted in time (concentration is 1-2%). The diluted starch paste should be used up in time. If it needs to be stored for a period of time, it must be kept at a temperature of about 65 °C. Otherwise, the starch paste is prone to aging, and delamination occurs, which affects the use effect.
3 The starch paste after gelatinization treatment should not be continuously stirred, especially to prevent high-speed stirring, so as to prevent the molecular chain of the paste from being sheared and destroyed.
5 Paste and dilute the paste, you can add in the slurry pool.
From Best Plus Pulp www.bestpluspulp.com We manufacture and customize the Pulp Paper Tray and Cartons, Shoe Pulp Tray, Egg Tray, Egg Cartons, Pulp Basket, Wine Pulp Tray and other customized Pulp packaging products.