Four factors influencing the strength of paper mol

2022-07-25
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Four factors affecting the strength of paper mold packaging products

① fiber strength

② bonding strength between fibers

③ surface area of fiber binding

④ distribution of binding bonds

in view of the above four factors, the solutions are:

1. In the pulping process, the medium consistency long fiber sticky beating method is adopted. Medium consistency beating refers to a beating method carried out in medium consistency beating equipment when the beating concentration is 46%. Long fiber sticky beating is a beating method that requires to avoid cutting off the fiber as much as possible, keep the fiber at a certain length, and carry out high wire separation and brooming. It has good swelling and hydration, and the change-over switch should be turned to the "loading" position. The advantages of this beating method are:

① less fiber cutting, more distortion and deformation, and good strength of finished products

② when the strength of paper products is the same, the beating degree and water retention value of pulp are low, and the dewatering performance is good

Jinmin new material is a scientific and technological company focusing on the research and operation of high-end new material industry. ③ refining time is shortened, energy consumption is reduced, equipment performance is improved and product cost is reduced. Due to reducing the range of concentration and dilution, the electric energy of medium consistency beating can save 20.30kw HT absolute dry pulp

2. After pulping, the pulp is loosened.

the manufacturer has a beating process but no pulping and loosening process, which makes the finished fiber lack the conditions to increase the strength. Although it takes only a few seconds for the paper material to pass through the dredger, the pulps crushed by the hydraulic pulper can be cut, separated and finely fibrosed by the dredger, which can not only make the pulp distribution of the paper products uniform, but also increase the strength of the finished products

3. Add reinforcing agent to increase the strength of the product; Adding waterproof agent to increase the waterproof of the product the test piece has extremely high glass transition temperature, good ablation reproducibility, high retention rate of high-temperature mechanical properties and moisture-proof performance

there are two ways to strengthen paper with chemical additives, one is internal reinforcing agent, the other is surface reinforcing agent. The internal reinforcing agent can be divided into dry reinforcing agent and wet reinforcing agent

the reinforcing agent used to increase the packaging products of pulp molded industrial products generally uses dry reinforcing agent. Dry reinforcing agent is a fine chemical used to enhance the bonding between fibers to improve the physical strength of paper products without affecting their wet strength. These chemicals have active groups with a certain molecular weight. Due to the bonding strength of their own colloidal molecules, they can form hydrogen bonds with the hydroxyl groups of cellulose, which can meet the requirements of paper product reinforcement

the commonly used dry enhancers include cationic starch, anionic starch, amphoteric starch, polybasic starch and ionic polyacrylamide

cationic starch and multi-component starch (including amphoteric starch) are not only good retention and drainage aids, but also good dry enhancers. Its strengthening principle is mainly 11) the maximum spacing between the lower fixture and the upper fixture shall be no less than 700mm; Through the electrostatic attraction between the cationic group in starch and the negative charge on the fiber surface, it is attached to the fiber surface and adsorbed with the fiber through the bridge of hydrogen bond, so that the broomed fibers form a whole of crosslinking, so as to achieve the purpose of improving the strength of paper products

starch shall be used as a reinforcing agent, and the dosage is generally 1 ~ 2% of the dry pulp material. Starch without gelatinization treatment cannot be directly added to the pulp pool. Starch must be gelatinized and processed into starch paste (dextrin can be purchased if there is no gelatinization condition). The gelatinization method is as follows:

① add a certain volume of soft water or clean cold water with low hardness into the gelatinization tank, start the mixer (the mixing speed is 60100 RPM), and then slowly add starch to fully disperse the starch. Generally, the gelatinization concentration is 5%, and then directly heated by steam. However, the steam pressure should not be too high to prevent the degradation of starch by high-temperature steam. It would be better if indirect steam could be used for heating

under continuous stirring, raise the temperature to 9095 ℃ to make it a gelatinizing solution, and keep it at this temperature for about 20 minutes. This step is very important. Attention should also be paid to the starch with incomplete gelatinization, because the starch particles are not fully dispersed, which will affect the use effect. However, the heat preservation time should not be too long, and the temperature should not be too high to prevent starch degradation under the action of high temperature for a long time

② the starch paste after gelatinization should be diluted in time (the concentration is 1 ~ 2%), and 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 ℃. Otherwise, the starch paste is easy to age, and the stratification phenomenon will affect the use effect

③ do not continuously stir the gelatinized starch paste, especially prevent high-speed stirring to prevent the molecular chain of the paste from being sheared and damaged

④ paste liquid after gelatinization and dilution can be added into the slurry forming tank

4. In order to increase the strength and waterproof and moisture-proof problems of paper mold industrial packaging products, add a kind of water-resistant reinforcing agent for paperboard after adding starch paste solution, with the addition amount of 5% of the dry weight of starch (it is OK to directly add starch paste and stir it evenly)

the honeycomb paperboard substrate and pulp molded products treated by this process have the advantages of water resistance, moisture resistance, smoothness, firmness, compression resistance and impact resistance

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