Formula and Manufacturing Technology of Adhesive (cooked glue)

Paste:Formula and Manufacturing Technology of Adhesive (cooked glue)

      Industrial caustic soda (NaOH) there are crystalline, rod-shaped, flake and 30% NaOH aqueous solutions. As long as the purity is qualified, caustic soda in any state can be used. The amount of caustic soda is added to oxidized starch and stirred for 20 minutes until the starch solution is translucent paste. Formula and Manufacturing Technology of Adhesive (cooked glue)

       The amount of caustic soda is too large, the glue solution has high fluidity, good transparency and long storage time, but the alkali content in corrugated peak sizing will also increase The corrugated box is easy to turn yellow, causing the ink on the surface of the corrugated box to change color; The amount of caustic soda is small. Formula and Manufacturing Technology of Adhesive (cooked glue)

        After adding it for 20 minutes, it will always be white or milky white paste, opaque and non sticky. Add another part of caustic soda solution as appropriate to make it become translucent glue. The amount of caustic soda is small, the adhesive is not good, the bonding force is poor, and it is easy to thicken. From the actual observation, the dosage of caustic soda is generally about 12% of starch.Formula and Manufacturing Technology of Adhesive (cooked glue)

Oxidant:Formula and Manufacturing Technology of Adhesive (cooked glue)

       In starch adhesives, the commonly used oxidants are hydrogen peroxide, sodium hypochlorite, potassium permanganate and so on. Potassium permanganate is used as oxidant, the dosage is easy to control, and the quality of the finished starch adhesive is also stable, but the color of the starch adhesive is dark coffee or brown black. Formula and Manufacturing Technology of Adhesive (cooked glue)

      The starch adhesive made of sodium hypochlorite and hydrogen peroxide as oxidant has light yellow color, but the quality of starch adhesive made of sodium hypochlorite is unstable in the process of use, which decomposes chlorine, making the operators feel uncomfortable with their eyes; Formula and Manufacturing Technology of Adhesive (cooked glue)

      Starch adhesives made from hydrogen peroxide often produce a large amount of foam and require defoamers. Formula and Manufacturing Technology of Adhesive (cooked glue)

       In addition, sodium hypochlorite is easy to decompose under sunlight or high temperature, so as to reduce the secondary chlorine content. In application, it is necessary to master its exact content at any time and appropriately increase the dosage. Formula and Manufacturing Technology of Adhesive (cooked glue)

       From the analysis in use, using hydrogen peroxide as oxidant has the advantages of stable quality, small dosage, low cost and fast reaction. It is an ideal material for oxidant.Formula and Manufacturing Technology of Adhesive (cooked glue)

       Oxidation reaction plays a key role in the preparation of cold high-strength and fast drying starch adhesive, If the oxidation is appropriate (the viscosity is 60-80 seconds 20-40 minutes after adding caustic soda), the solubility of starch is improved, the film-forming ability is good, and the adhesion is strong;Formula and Manufacturing Technology of Adhesive (cooked glue)

       if the oxidation is not enough, the macromolecule degradation is less, and its properties are the same as those of starch. Formula and Manufacturing Technology of Adhesive (cooked glue)

      After adding caustic soda, it remains dilute for a long time, and even does not stir (react with caustic soda for more than 40 minutes, and the viscosity is higher than 100 seconds), so it is necessary to add oxidant for secondary oxidation, such as excessive oxidation, open chain of starch ring structure.Formula and Manufacturing Technology of Adhesive (cooked glue)

      low viscosity, or even lose bonding ability (react with caustic soda for 20 minutes, and the viscosity is lower than 40 seconds). Therefore, pay special attention to the use of oxidant content and ratio.Formula and Manufacturing Technology of Adhesive (cooked glue)

       Temperature also plays a role in the oxidation process. The higher the temperature, the faster the oxidation. Generally, the oxidation reaction takes 10-15 minutes in summer, 15-20 minutes in spring and autumn, and about 30 minutes in winter. Formula and Manufacturing Technology of Adhesive (cooked glue)

      The oxidation reaction time is prolonged, the oxidation is complete, and the product quality is stable, but too long will affect the production cycle.Formula and Manufacturing Technology of Adhesive (cooked glue)

       The specific amount of oxidant changes with the change of starch. The amount of starch is small, and the amount of oxidant is also small, The content of sodium hypochlorite (10%) is about 28% of starch, the content of hydrogen peroxide (27.5%) is about 4% of starch, and the content of potassium permanganate is about 2% of starch. Formula and Manufacturing Technology of Adhesive (cooked glue)

        The method to judge whether the oxidation is appropriate is to add caustic soda, stir for 20-40 minutes, and measure its viscosity for about 60 seconds (summer) is better. In this way, the finished product is stored for about 2 hours, the viscosity is about 50 seconds, and the viscosity is stable at 40 ± 10 seconds after one day. Formula and Manufacturing Technology of Adhesive (cooked glue)

         In addition, the amount of oxidant should be appropriately increased in winter when the temperature is low, and reduced in summer when the temperature is high and the reaction is fast.Formula and Manufacturing Technology of Adhesive (cooked glue)

Strong solid catalyst (desiccant for short):Formula and Manufacturing Technology of Adhesive (cooked glue)

      The main factor that distinguishes the cold-made high-strength and quick drying series starch adhesives from other adhesives is the selection of “strong catalyst”. The strong solid catalyst is formed by the polymerization of several salts and organic-inorganic compounds.Formula and Manufacturing Technology of Adhesive (cooked glue)

      In the process of adhesive production, as long as the time and dosage are appropriate, it not only speeds up the reaction speed, but also flocculates and crystallizes quickly through the chemical reaction between the polymer and oxygen in the air after sizing, which speeds up the adhesive film forming speed, shortens the carton drying time and improves the strength of paperboard.Formula and Manufacturing Technology of Adhesive (cooked glue)

       Therefore, the adhesive bonding speed (initial adhesion, total adhesion and fiber destruction) are more than several times higher than those of similar starch adhesives. In addition, the cardboard has high hardness and good stiffness. Formula and Manufacturing Technology of Adhesive (cooked glue)

      The amount of strong catalyst in the adhesive is less than 5kg per ton of water, which does not play a due role. Formula and Manufacturing Technology of Adhesive (cooked glue)

       The amount of water per ton is higher than 15kg. The adhesive conjunctive is too fast, which is easy to produce degumming of cardboard. Therefore, the dosage proportion should be strictly controlled. The normal dosage standard is 6-12kg / ton of water .Formula and Manufacturing Technology of Adhesive (cooked glue)