Corrugated Board Adhesion Problem Consolidation - Paste Technology (I)

Two high-quality carton guarantee - the role of paste is increasingly important

The importance of paste quality in the corrugated board production process has been recognized by more and more carton manufacturers, and it is very appropriate that some people compare the paste to the “blood” of the cardboard production line. Because, the quality of the paste production directly affects the quality of the board and the speed of the corrugated board production line, and it plays an absolute role in the quality of the board. Therefore, how to improve the paste quality and how to use glue properly and reasonably becomes very important. Relevant personnel must fully grasp the paste making method and the proportion of raw materials, and timely adjust the gelatinization temperature and viscosity required for paperboard bonding so as to enhance the strength of the paperboard, reduce the loss and reduce the cost.

(A) Pasting process and operation method

The paste making process and related operations are the most important. Because, to improve the paste quality and the correct and reasonable use of paste, is to produce high-quality corrugated cardboard guarantee. Of course, for the paste-making process and related operations, each manufacturer is different, and there are methods suitable for actual production conditions. Next, we introduce one of the more ideal paste making process.

1, carrier

1). Due to the use of additives to make the paste when the amount of carrier production only accounts for 20% -24% of the total, there will be carrier tank stirrer blade can not hit the tank material, the material can not be fully mixed, affect the results. Therefore, the length of the carrier stirrer shaft should be lengthened so that the blades extend into the material, or the main body can be added in several portions in accordance with the amount of the secondary paste. However, due to the large viscosity of the carrier paste, it is bound to cause inaccurate measurement;

2). The discharge valve for the carrier tank production factory is about 1.5`, -2`, which makes the discharging too fast. It is difficult for the carrier slurry to be fully mixed after being added to the main body. The solution is to install a 2`-1/2` valve in the discharge valve, reduce the diameter of the beam joint, make the outlet diameter less than 15 mm, and control the discharge time to be 8 minutes to 12 minutes;

3). According to the properties of the carrier slurry and the manufacturing method, if there is agglomeration and slow discharge of the paste, the function of the carrier stirrer motor should be increased, the shape and size of the stirrer blade should be changed, and the installation stability of the carrier can be checked. .

2, the main body

1). The main agitator is preferably a speed-regulating motor, regulating the rotation speed between 400 rpm and 1400 rpm;

2). When the carrier slurry is injected into the main body, the main agitator should be in the stirring state, and the rotation speed should be between 400 rpm and 800 rpm.

3). After the carrier slurry is poured into the main body, stirring is continued for 15 minutes and N20 minutes. The two must be mixed thoroughly.

3, the injection of additives

1). After the additive is weighed, the outlet of the container cannot be larger than 14 mm, the injection time is basically controlled between 5 minutes and 10 minutes, and the agitator must be in agitated state when the additive is injected;

2). After the additive is injected into the main body, the stirring speed is increased, and the stirring is continued for 10 minutes to 20 minutes. If the stirring is not thorough after 20 minutes, the jelly liquid appears jelly, and the stirring intensity is too small. The main motor must be replaced. If it is still not ideal, the shape, angle, and area of ​​the paddle mouth should be modified to ensure that the mouthwash is fully mixed with the paste liquid in the boiling state;

3). Be sure to use viscometer to test the viscosity before you apply on the machine.

4, other

1). Do not try to reach the viscosity requirement by using a prolonged mixing time without stirring:

2). The amount of water injected by the carrier and the main body must be accurate;

3). Use unused residual glue (more than 12 hours), it should be injected into the storage tank or paste tank stirring for 5 minutes -10 minutes, it is best to add 40% of the fresh paste and stir well;

4). The use of additives, the factory should be based on their own business conditions and regional climate, paper density, water absorption, moisture content, etc., adjust the glue production time, the proportion of materials, such as the summer should increase the amount of starch, winter decrease.

(B) to achieve the best efficiency of starch adhesive

Starch adhesives are used by more and more carton manufacturers because of their advantages such as high adhesive strength, large cardboard stiffness, non-absorbent, soft, non-corrosive, non-polluting, and low cost. However, the configuration of starch adhesives may still cause quality instability. The most critical process is the degree of oxidation. Oxidation is too high, the viscosity of the adhesive is low, and the adhesive strength is poor, which can easily cause poor adhesion of the paperboard. Insufficient oxidation, high viscosity of the adhesive, inability to use on the machine, slow drying of the cardboard, short storage time, easy crusting and gelation. Therefore, how to grasp the degree of oxidation is a key process for the production of adhesives.

The starch must be modified before it is formulated into a binder. The purpose of the modification is to improve the binding and flowability of the starch paste. Unmodified starch obtained a thick paste after gelatinization. In order to prepare a "glue" with good flow properties, it is necessary to modify the starch. Modification methods include acid conversion method, enzyme conversion method, dextrinization method, etherification method, oxidation method, and the like.

In the process of disposing the adhesive, when the temperature of the bottom water is 20 degrees Celsius, the amount of potassium permanganate should be controlled at 0.4 kg to 0.5 kg per 25 kg of corn starch. If the cassava starch is used, it should be appropriately reduced.

(to be continued)