Corrugated carton adhesive technology (below)

In the production process of corrugated board, the quality of the paste is an important factor that directly affects the quality of the corrugated board and the production speed of the corrugating machine. Some people justify the importance of paste quality to the quality of cardboard as the importance of blood to the human body.

From the quality of corrugated board, many quality problems are caused by the quality of paste or improper use of paste. For example, common cardboard degumming, cracking, poor adhesion, cardboard warping, corrugated machine speed slowly open and fast, and so on. The source of the problem can be found in the paste quality and paste usage methods.

1. Corn starch glue

Most of the cartons used today are homemade or purchased cornstarch gums. The high-quality corn starch glue not only has good adhesive strength, but also can increase the bearing pressure and strength of the carton, and the box body is not easily deformed. Advantages and disadvantages of corn starch glue and production process, environment, raw material quality, mixing time and so on are closely related. As we all know, no more rumors.

Now we will introduce the quality requirements of cornstarch, which is one of the main raw materials for making glue, and the water ratio of starch glue and auxiliary materials, etc. for your reference. Corn starch quality requirements: fineness of 98 mesh -100 mesh, ash content does not exceed 0.1%, moisture content of 14.0%, acidity 20cc/100g; sulfur dioxide 0.004%, odor normal, white or slightly yellowish color. When starch quality is not met in this standard when making glue, the water ratio may be appropriately reduced depending on the quality. As the temperature rises, the water ratio should be reduced accordingly, and borax and protopine should be increased as appropriate, and H202 should be appropriately reduced. After the cooked rubber is prepared, it should not be released for a long time, especially in the summer, it is best to use with the use of formaldehyde, 3%-4% of formaldehyde, 0.1% of glycerin, and 0.1% of boric acid, which can increase the water resistance of the paper and speed up Bonding speed, enhance cardboard hardness.

2. Environmentally-friendly chemical glue

Eco-friendly chemical adhesives, PVA adhesives, can also be used when applying sticker boards. It is characterized by a smooth, straight, well-glued corrugated cardboard, which does not distort over time. Its production method is (100kg adhesive as an example):

The ratio of materials used was: polyvinyl alcohol 13.7kg, acetic acid polyvinyl alcohol emulsion 2.74kg, oxalic acid 1.37kg, water 82kg (water ratio 1:6).

First, the water was heated to 900C, polyvinyl alcohol was added and stirred well, heating was continued until the water boiled, and the temperature was kept for 3 hours. Then, oxalic acid was added for stirring, and finally polyvinyl acetate emulsion of acetic acid was added to stir and mix well.

3. Drying catalyst for drying

The main factor that distinguishes cold-strength, high-drying and fast-drying starch binders from other binders is the selection of a "dry catalyst." Dry catalyst is formed by the polymerization reaction of several salts and organic compounds. When used in the adhesive production process, it only needs to be suitable when used, not only to speed up the chemical reaction, but also to chemically react with the oxygen of the air after the sizing and quickly flocculate. Crystallization accelerates the conjunctival speed of the adhesive, shortens the drying time of the carton and increases the strength of the cardboard. Therefore, the adhesion speed of the adhesive (primary viscosity, full viscosity, and fiber destruction) is several times higher than that of the conventional starch glue, and the cardboard has high hardness and good stiffness. The amount of dry catalyst is less than 5kg per ton of water in the adhesive, which will not achieve its proper function; the amount of water per ton is higher than 15kg, the adhesive film is too fast, and the debonding phenomenon of the cardboard is easy to occur. Therefore, the ratio of dispensing should be strictly controlled. . The normal water usage standard is 6.15 kg/ton.

4. Improvements

(1) By improving the gap control (supplying the roller to the corrugating roller, the supply roller of the container squeegee roller pair), the surface of the rubber roller is optimized (fine grid engraving method), and the double-sided machine paste unit uses pressure shoes Load technology; the use of higher solids in the starch paste can make the paste on the paper web more uniform and make the paperboard smoother. The above improvements will reduce the total amount of glue used by 3g per square meter.

(2) In order to produce a smoother board, the properties of the base paper and starch paste must meet the specifications of the equipment characteristics. To regulate and improve the moisture of the base paper, control the temperature difference of the surface of the paper web within ±1%, and improve the paper fiber orientation and the average paper thickness; control the solid content of the starch paste at 25%-28%, with more Good adhesion. The improvement of the flatness of the cardboard makes the subsequent processing machine faster and produces less waste paper

Formulation of finished rubber for carton production (see table to the right)

When the formulations shown in the table are used, timely adjustment shall be made according to the local environment temperature and humidity, the quality of raw materials used, the quality of the raw materials themselves, and the specific production process conditions. In order to further improve the drying speed and stiffness of corrugated board, Formula No. 1 can be used to meet the requirements in production, such as the application of Nos. 5 and 6 for the formulation of adhesives for automatic veneer and honeycomb board production. Ordinary corrugated board production, the drying speed, stiffness are better than corrugated board for the production of adhesive corrugated board. It should be noted that the viscosity of the adhesive must be properly adjusted.

(Note: The above formula produces 1400kg to 1500kg of finished rubber. When calculating the cost, please settle the actual situation.)

Author / Chen Xirong