Corrugated board production line paper paste technology and problem solving two

Principles and Functions Paste Basics

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NO-CARRIER SYSTEM Principle: The use of a slight excess of caustic soda results in the gradual expansion of the starch granules and the resulting viscosity and suspension effect. As the starch gradually expands, the viscosity of the paste will gradually increase as the starch granules expand. To a certain extent, after the viscosity reaches the required standard, a viscosity stabilizer or boric acid is added at this time to neutralize the excess alkali so that the starch particles do not continue to expand, the viscosity no longer rises, and the viscosity of the paste is controlled Within the scope of use, and adding borax to increase the viscosity of the paste and adding a glue reinforcing agent, using its functional group similar to the surface fiber of the paper, the paste has excellent penetration force, and causes bridging of starch and paper surface fibers Anti-adhesion effect due to reaction.

CARRIER SYSTEM adds all the required caustic soda to the puddle. Due to the large excess of caustic soda, the rapid expansion of the granules of the loaded starch (chemical starch or general starch) is caused by the large expansion of the starch granules. In the event of a rupture, AMYLOSE and AMYLOPECTIN (as shown in Figure 1) are released and the paste masterbatch is mixed with the starch and water phase in the powder bucket. The high viscosity and water retention can suspend the raw starch particles in the powder water and produce viscosity. Due to the penetrating power of amylose, the amylopectin molecule has the shape of branches and poor penetrating power. Therefore, the more advanced the chemical starch, the The higher the amylose molecular content, the better the permeation effect, can greatly increase the speed and bond strength, but the higher the relative price, the content of linear molecules of various types of starch is as shown in Exhibit 1.

Adjustment of details in the paste and its solution

Material related conditions of use

Water temperature The higher the temperature of water, the stronger the activity of liquid alkali, so after the second liquid base is added, the viscosity of the paste will rise quickly, and the amount of secondary liquid alkali must be reduced to achieve a stable viscosity. The lower the temperature, the opposite.

The amount of water used for water is reduced, the drying speed of the laminator can be increased, and the lamination strength and the cardboard stiffness can be increased at the same time. Therefore, cardboard with high material and high basis weight must reduce the amount of water used to increase the speed.
Starch corn flour and cassava flour are the same: Due to the difference in origin and production climate, different brands of corn flour or tapioca flour require different amounts of liquid caustic soda for swelling and swelling. When preparing paste, the amount of liquid caustic soda must be omitted. Make adjustments. Different: Because the cassava powder is more viscous, the viscosity of the paste prepared by the cassava flour is lower than that of the corn flour.

Liquid caustic (soda) caustic soda is generally 30% liquid caustic soda. If caustic soda is used, it is 0.30 times as caustic soda.

The greater the amount of liquid caustic soda, the lower the gelatinization temperature of the paste, and the better the penetrability, but if the weather is too hot, the temperature of the paste at the site will rise, the liquid caustic activity will increase, and the viscosity will increase. Therefore, the climate is different. The amount of alkali must be adjusted slightly to achieve a stable viscosity and an appropriate gelatinization temperature, which are adjusted with the second amount of caustic soda. Remarks: The first time the alkali is added, stirring until the viscosity rises to a standard time of 25 ± 5 minutes is appropriate, so that there is ample time for uniform expansion of the starch granules to obtain the correct viscosity. If the viscosity rises too slowly, then Increase the amount of caustic soda, if the viscosity rises too fast, reduce the amount of caustic soda.

Material related conditions of use

Stabilizer Addition Time When the paste viscosity reaches the required level, it can be added. After mixing, the viscosity of the paste will slightly decrease.

The amount of borax borax borax can help the paste director to stay in the top of the dome, the amount of starch is about 1.5, if the temperature is too low, the viscosity is too low to increase the amount of borax to shorten the drying time, if the temperature is too high or High viscosity can reduce the amount of borax to increase penetration.

The amount of starch modifier increases the adhesive effect of the paste, improves the stickiness of the paste, and has the effect of moisture-proof, anti-chemical water and anti-adhesion.

Symptoms Causes and Solutions

The viscosity is too high 1 Stabilizer is added when the viscosity is too high. When the viscosity of the paste is appropriate, stabilizers can be added
Overdose of 2 liquids caused an increase in the viscosity of the paste during use. Add powdered water (the raw starch is mixed with water and then added) to make the viscosity of the paste down and stable, or to remix a low-viscosity paste to mix with it to reduce the viscosity and reduce the amount of liquid alkali.

Viscosity is too low 1. Stabilizer is too early to add 1. Stabilizer can only be added after the paste viscosity reaches the standard.

2. The viscosity of the paste is not increased due to insufficient liquid alkali 2. The paste with a higher viscosity is reconstituted and mixed to increase the viscosity.

For a long time, China has always been a low-grade corrugated paperboard production and a low-end market. The carton plant paste has been at a low level, the traditional concept can not be changed, and it has been considered that adding paste and additives will increase the cost, in fact, such as Zhejiang Ji'an paper containers The company's products use the company's products, the average amount of paste is three layers of 10G, five layers of 18G, in the production process, extremely stable, in the past more than one year due to glue problems did not produce cardboard scrap, the design speed of 250 meters / In the actual production, in the actual production, the five floors reach 200m/min, the third floor reaches 240m/min, and the fit is completely good. Therefore, in today's highly competitive market, it is hoped that all carton manufacturers should consider quality assurance. Under the circumstances, maximize the efficiency of your machine and reduce losses to increase profit margins and create greater profit margins.

(Shanghai Guan Ang Industry & Trade Co., Ltd.)