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 the 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 the cardboard is increased. 0.1-1mm, cardboard hardness increased by 10-30%, bond 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 body 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 of the main carrier container is stirred for 1 to 2 hours, if the viscosity is found to be too low (viscosity is lower than 20 seconds), the amount of caustic soda is insufficient, and caustic soda must be added according to the situation (to ascertain the net content of caustic soda used). When caustic soda is added, a certain amount of caustic soda can be opened with 5 to 10 times cold water, slowly added to the container, and then continue stirring for about 1 hour.
2 After the main and carrier liquids are mixed (stirred for 1 to 2 hours), if the viscosity is too high (measured with 4 cups), higher than 80 seconds, it indicates that the amount of caustic soda is too large, and the dosage should be reduced according to the situation. 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 final viscosity of the finished starch binder product is 20-60 seconds (coating - 4 cups). 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 there is degumming 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, check if the amount of glue applied is too small; 2 if the viscosity of the adhesive is too low; 3 adhesion Whether the agent is too fast, that is, when the single-sided cardboard passes through the metastable roller and is compounded with paper or liner paper, the conjunctiva is partially conjunctiva. For example, the conjunctiva must be reduced in desiccant dosage according to the situation.
4. Reference formula for adhesives for single-sided corrugator: 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 Drier: 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.
Second, the corrugated board adhesive bonding and the speed of the automatic line, temperature The adhesive strength of the paper puller is an important indicator of the physical properties of the paper, its quality is related to the quality of the entire carton. Because a large part of the cartons produced by the automatic line are used for export packaging, and the goods are loaded into the cartons, they must be stored, transported, transported, and transported for a long period of time such as stacking and jolting. It is not uncommon for cartons to fester and pressure collapse due to poor adhesion. This not only causes damage to cartons manufacturers and exporters, but also affects our country’s external noise. Therefore, how to improve the adhesive strength of the cardboard is an important issue for us who have automatic line manufacturers. We analyze the causes of the effects of adhesion, and consider that the speed and temperature of the automatic line are two more important factors.
The bonding process of cardboard involves complex physical and chemical changes. It depends not only on the nature of the adhesive, but also on various conditions. The properties of the adhesive include viscosity, pH, and gelatinization. Temperature and other indicators, the size of this indicator directly affect the bonding strength of the cardboard, so when we make adhesives, we should do:
1, suitable viscosity.
2, the appropriate concentration.
3, the viscosity change should be small.
4. Good initial adhesion.
5, no precipitate.
6, make the cardboard hard. ?
Based on the above points, we should strictly follow the operating procedures and process requirements in the production of adhesives, taking into account various environmental impact factors, in order to ensure the quality of cardboard bonding. Therefore, when we study the relationship between the following adhesion and speed and temperature, we can assume that the adhesive is in compliance with the requirements, which is more conducive to the analysis of the relationship between them.
(A) The relationship between adhesion and speed 1. The bonding of single-sided corrugated cardboard in a single-sided machine, and the process of adhesion of starch granules in the adhesive is:
Water Absorption - Swelling Wetting - Destruction - Dispersion - Dehydration - Curing (macromolecular chain formation).
If the speed of the single-sided machine is too fast, the amount of corrugated paper will be reduced, and the width of the coating will be narrow, which will affect the adhesion effect.
If the speed of the single-sided machine is too slow, not only will the amount of glue applied be increased, but the starch adhesive will also be hardened due to an excessively high temperature and the adhesive effect will be lost.
2. What is the relationship between speed and adhesion of a double-sided machine?
Double-sided machine bonding is the combination of single-sided corrugated cardboard and paper. The bonding is the key to the bonding of the whole board. The speed control is good, not only will it make the corrugated paper and paper composite good, but also make up for the single-sided corrugated paperboard. Adhesion defects, on the contrary, if the control is not good, it will cause poor bonding of the entire cardboard.
If the speed of the double-sided machine is too fast, the amount of glue applied to the paper and corrugated paper will be reduced, and the amount of heat will be too low, so that the starch will not be gelatinized, resulting in poor adhesion.
If the speed of the double-sided machine is too low, the amount of glue applied to the paper and corrugated board will increase, the heat will be too high, the structure of the starch will be destroyed, and the adhesive structure of the single-faced corrugated board will be destroyed, causing the board to burn.
(b) The relationship between adhesion and temperature is shown in the following table, which is the relationship between the temperature, speed, and vapor pressure of the automatic line (see Table 1). ?
Table 1
Steam pressure (kg/cm2)
Speed (m/min)
Temperature (°C)
6.0
6.5
7.0
7.5
8.0
9.0
10.0
12.0
30
35
40
50
60
80
100
150 or more
158
161
164
167
170
176
179
187
When the corrugated board is recombined on a double-sided machine, since the first group of hot plates ensures high temperature bonding, and the second and third groups are used to dry and stabilize the cardboard, how to adjust the temperature of the three groups of heating plates is very good for the bonding effect. The important role. If the temperature of the double sided machine is too high, the adhesive has already gelatinized in a very short time, and excessive drying is performed on the hot plate at other times. This will cause excessive drying of the paperboard. In production, generally, only the production of three This happens only when the cardboard is in layer. Therefore, if high speed operation is not possible due to other conditions, several sets of heating plates should be turned off or turned down.
If the temperature of the double-sided machine is relatively low (cannot be lower than 155°C, ie, the pressure cannot be lower than 5kg), so that the board runs on the double-sided machine, it takes a long time to reach the adhesive paste, and the board cannot be fully baked. Dry, such as cardboard with high water content, not only affects the adhesion, but also causes warpage and low thickness. Therefore, when this happens, the production rate should be high or low.
Third, how to solve the problem of degummed face paper Degummed face paper refers to the paperboard produced from the automatic line, is subject to a small external force, the face tile that is completely or partially detached from the cardboard, this phenomenon is mainly due to the phenomenon of adhesive Quality, temperature and speed, as well as the performance of the base paper.
(A) The effect of adhesive degumming In the previous section we talked about the effect of adhesives on the thickness and adhesion of paperboard. The same adhesive has a direct impact on degumming.
Firstly, an excessively high viscosity of the adhesive will increase the amount of glue applied per unit area of the paperboard. This will result in a thicker bond zone between the paperboard and the paperboard. Relatively speaking, the penetration of the surface between the two layers of paperboard. Smaller, resulting in degumming; the other hand, if the viscosity is too small, will produce a sticky effect of the free binding of starch molecules, so that the adhesive tape becomes thinner, can also cause degumming.
Second, the gelatinization temperature of the binder can also cause degumming. If the gelatinization temperature is high, the paperboard may not reach the gelatinization temperature at an irregular temperature and speed of the automatic double-sided machine, and the paperboard may not stick to the paperboard. Of course, the most severe degumming will occur at this time. If the gelatinization temperature is too high, the cardboard will be burned out and the adhesive effect will be destroyed. Therefore, when making the adhesive, the viscosity and temperature should be adjusted.
(B) the impact of the speed and temperature of the automatic line on the degumming The front has repeatedly mentioned the impact of the speed and temperature of the automatic line on the paperboard adhesion, the same reason, for the degummed paper, the speed and temperature can not be ignored (see Table 2) .
Table 2
Low temperature (below 155°C)
Medium temperature (155°C-170°C)
High temperature (above 170°C)
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