Four factors that affect the strength of paper packaging products

1 The strength of the fiber itself;
2 The bond strength between fibers and fibers;
3 fiber-bonded surface area;
4 The distribution of bond bonds.
For the above four factors, the solutions are:
1. In the pulping process, medium thick long fiber viscous beating is used. Medium-strength pulping refers to a beating method carried out in medium-strength pulping equipment with a beating concentration of 4-6%. The long-fiber viscous beating method requires that the fibers be cut as much as possible so that the fibers retain a certain length. , And a high degree of defibrillation, with a good swelling and hydration of a beating method. The advantages of this beating method are:
1 Less fiber cuts, more distortion and better finished product 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 better;
3 Beating time is shortened, energy consumption is reduced, equipment performance is improved, and product cost is reduced. The medium-strength beating can save 20-30kw ht of absolute pulp by reducing the concentration and dilution.
2. After the pulping, the pulping process has been conducted by the manufacturer and there is no pulping and deliming process. This results in a lack of strength for the finished fiber. Although the time required for the paper material to pass through the disintegration machine is only a few seconds, the pulverization of the pulverized pulp by the hydraulic pulper is cut off, disentangled, and finely fibrillated by the disintegrator, which can not only make the paper product cloth uniform but also increase the finished product. strength.
3, add enhancer to increase the strength of the product; add waterproof agent to increase the product's waterproof, moisture-proof performance.
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. Intensifiers for internal use are divided into dry enhancers and wet enhancers.
Reinforcing agents used to increase packaging products for pulp molded industrial products generally use dry reinforcing agents. Dry reinforcing agents are fine chemicals that are used to increase the bonding between fibers to increase the physical strength of paper products without affecting their wet strength. These chemicals have active groups with a certain molecular weight. Due to the binding strength of their own colloidal molecules, they can form hydrogen bonds with the hydroxyl groups of cellulose, which can meet the requirements for the enhancement of paper products.
Commonly used dry enhancer species are: cationic starch, anionic starch, amphoteric starch, multiple starch and ionic polyacrylamide.
Cationic starches and multiple starches (including amphoteric starches) are both good retention aids and good dry enhancers. Its strengthening principle is mainly through the electrostatic attraction between the cationic groups in the starch and the negative charges on the surface of the fiber, which attaches to the surface of the fiber and adsorbs to the fiber through a hydrogen-bonded bridge, so that the deuterated fibers form an adhesive between the fibers. The overall, so as to achieve the purpose of improving the strength of paper products.
The use of starch as a reinforcing agent, the amount is generally 1 ~ 2% of the dry pulp material, the starch can not be directly added to the pulp pool without gelatinization, the starch must be gelatinized, processed into a starch paste (no gelatinization conditions can be Purchased dextrin) before use. 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, turn on the stirrer (agitating speed is 60-100 rpm), and then slowly add starch to fully disperse the starch. Generally, the gelatinization concentration is 5%, and then the direct steam heating, but the steam pressure can not be opened too high, to prevent high-temperature steam degradation of starch. If you can use steam heating between the better.
With continued stirring, the temperature was raised to 90-95°C to make it a gelatinized liquid, and it was kept at this temperature for about 20 minutes. This step is very important, and we must also pay attention to the starch that is not fully gelatinized, because the starch particles are not fully dispersed and influence the use effect. However, the holding time should not be too long and the temperature should not be too high, so as to prevent degradation of starch under high temperature for a long time.
2 The gelatinized starch paste should be diluted in time (concentration of 1-2%). The diluted starch paste is best used 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 ageing and stratification may affect the effect of use.
3 The starch paste after gelatinization should not be continuously agitated. In particular, high-speed stirring is prevented to prevent shearing and destruction of the molecular chain of the paste liquid.
4 The gelatinized and diluted paste can be added to the slurry pool.
4, in order to increase the strength of paper packaging industry packaging products and waterproof moisture problem, add a starch paste after adding a cardboard water-reinforcement agent, add 5% of the dry weight of starch (add directly to the starch paste can also be mixed ).
The honeycomb paperboard substrate and the pulp molded product processed through this processing process have the advantages of water resistance, moisture resistance, smoothness, firmness, pressure resistance, impact resistance and the like.