Adhesive production problems on single-sided and sampan sheet production lines

Most of the domestic corrugated paperboard production lines use starch adhesives, and their bonding quality is obvious to all. Its production methods are also varied; however, its raw materials are basically the same, mainly including: starch, caustic soda, borax, and some formulas plus appropriate amounts of hydrogen peroxide. However, there has been no major breakthrough in the adhesive production process so far.
Domestic or even international efforts are still devoted to the study of methods for improving adhesives. Their main goals are how to improve the adhesive strength of adhesives and how to improve various properties of paperboard. The factors affecting the quality of adhesives are very complicated. Such as the ambient temperature, the quality of starch, the amount of caustic soda and other auxiliary materials, and the stirring speed of the mixing time, the adhesive can only be said to be half successful. The factors affecting the adhesive strength of the corrugated board are also related to the production speed of the automatic line. Temperature, corrugating roller, paper and other factors have a direct relationship.
This article describes a new method for making raw rubber in corrugated cartons. The principle is: Add a strong catalyst, also referred to as desiccant, on the basis of existing adhesives. After adding this agent, apply the adhesive to corrugated paper. Rapid solidification during aging, the wells in the corrugated board in the follow-up process to maintain the original thickness, while cardboard hardness, side pressure intensity has also increased.
Through multiple manufacturers' use and testing, the adhesive has a 50% increase in glue rate compared to the original technology (the original technology generally produced 5 tons of glue per ton of starch, and the technology can produce 7.5-9 tons of glue), and the thickness of paperboard is increased. 0.1-1mm, cardboard hardness increased by 10-30%, adhesive strength, side pressure strength, etc. have been improved, but also better than the national export standards, the raw rubber production technology is introduced as follows:
First, single-sided machine and corrugated board production line adhesive production technology 1, formula: unit; kg
Water: 1000 Starch: 140～180 Desiccant: 4～6 Caustic soda: 7～12.5
Borax: 5-6
2, process flow and production methods:
1 Main container: Water: 600kg + starch: l40 ~ 180kg + desiccant: 4 ~ 6kg
2 Carrier Container: Water: 400kg + caustic soda: 7～12kg
3 Add the liquid in the fully stirred carrier plant container slowly into the main container. After thoroughly stirring, add 10 times hot water-soluble borax solution to the mixture of the main body and the carrier. Stir in winter for about 2 hours. Stirring is completed in the summer for 1 hour to complete the finished starch adhesive and can be put into a storage tank for use.
3, matters needing attention:
1) If the mixture in the main carrier container is stirred for 1 to 2 hours, if the viscosity is too low (viscosity is less than 20 seconds), the amount of caustic soda is insufficient, and caustic soda must be added appropriately according to the situation (To determine the net content of caustic soda used When adding caustic soda, a certain amount of caustic soda can be chilled with 5 to 10 times the water, slowly added to the container, and then continue stirring for about 1 hour.
2) After the main and carrier containers are mixed (stirred for 1 to 2 hours), if the viscosity is too high (measured with 4 cups), higher than 80 seconds, the amount of caustic soda is too large. At the same time take remedial measures to give dilution. According to the proportion of water, starch, desiccant and borax mixed liquid (without caustic soda), the thick starch adhesive can be added according to the proportion of the formula, and the mixture can be fully stirred.
3) The viscosity of the finished finished starch binder is preferably in the range of 20 to 60 seconds (measured in 4 coats). The single-layer corrugating machine adhesive viscosity is preferably 30±5 seconds, and the adhesive viscosity of the three-layer and five-layer corrugated cardboard production line is preferably 40±10 seconds.
4) If the degumming phenomenon occurs on the corrugated board produced on the three-layer or five-layer automatic line and there is 1-2cm adhesion on both sides of the board, please check:
1 Is the amount of sizing too little?
2 whether the viscosity of the adhesive is too low;
3 if the adhesive is too fast, that is, when the single-sided paperboard is coated with a roller and then compounded with paper or liner paper, a part of the film is conjunctiva. If the conjunctiva is to be reduced, the amount of desiccant should be reduced according to the situation.
4. Reference formula for single-side corrugating machine adhesives:
Unit: kg
Water: 1000
Starch: 160
Desiccant: 6 caustic soda: 11 to 12
Borax: 6?
5. Reference formula for adhesives for automatic production lines for three-layer and five-layer corrugated cardboard:
Unit: kg
Water: 1000
Starch: 180
Desiccant: 4-5
Caustic soda: 11.5 to 12.5
Borax: 6
The starch adhesive produced by using the above two kinds of starch adhesive preparation process and raw material matching method is characterized in that a strong catalyst (abbreviated as desiccant) is added.
The addition of a strong catalyst increases the initial tack and full tack time of the starch binder. At the same time, the adhesive strength of the starch binder, which is less strong than the solid catalyst, is increased by 30% under natural drying conditions, and the moisture content of the corrugated cardboard is properly controlled. , A single unit of corrugated board using the starch binder can be put into the next process for 30 minutes to produce, thus ensuring that the thickness and strength of the corrugated board in the production process is not affected by other factors.