Specific steps of Dongguan White latex process:
1. The polyvinyl alcohol powder was thoroughly dissolved in deionized water and filtered. (PVA-1788 2488, etc.)
2. Put the polyvinyl alcohol glue into the stainless steel reactor (it can also be used in the enamel reactor, but the heat transfer effect of the enamel reactor is not as good as that of the stainless steel reactor), add emulsifier OP-10, and start the mixer to make it evenly mixed.
3. Add 15%(6.9) of the total amount of polyvinyl acetate monomer and 40%(0.036) of the formula amount of potassium persulfate into the stainless steel reactor, continue stirring, and begin to heat up. Stop heating when the temperature rises to 60-65℃. It should be noted that the initiator of potassium persulfate should be first mixed with pure water into an 8%~10% aqueous solution, several times added.
4. Under the action of initiator, although the heating stops, the temperature rises automatically. When the temperature is above 65℃, the reflux device of the reactor begins to appear. When the temperature rises above 80℃, the reflux gradually decreases. At this time, the drop of polyvinyl acetate monomer from the reaction kettle should be added, the drop acceleration should be controlled at about 10% of the total drop per hour (i.e., about 4.6). In the reaction process, the reaction temperature should be paid close attention to and cooling water should be added to the reaction kettle jacket to control the reaction temperature, which should not be higher than 80℃.
5. The initiator was also added along with vinyl acetate monomer, and the amount added per hour was about 4.5% of the formula amount.
6. The addition of vinyl acetate and initiator should be controlled at about 8h. Due to the action of initiator, the reaction is strong. After the monomer is added, the reaction temperature will rise by itself. When it rises to about 93℃, the temperature will be kept warm for 30min. The polymerization reaction is basically complete.
7. Open the cooling water to reduce the temperature in the stainless steel reactor to below 50℃, add sodium bicarbonate solution (should be dissolved in 10% concentration in advance) and dibutyl phthalate, pH value is adjusted to 6~7.
8. The mixer in the stainless steel reaction kettle should not be stopped all the time. When it is cooled to room temperature, the finished white latex product should be stopped mixing, feeding and packaging.
9. When the viscosity of white latex products is too large and water resistance is poor, the dosage of polyvinyl alcohol in the formula can be appropriately reduced.
10. If the stability of Dongguan white latex emulsion is poor, the dosage of some initiators can be appropriately reduced in the formula, too little will not be triggered, resulting in difficult polymerization of monomer.
11. The dosage of dibutyl phthalate should not be too much, not more than 10% of monomer, otherwise the adhesive of white latex products will decrease and increase the cost. Its main function is to increase the toughness of emulsion and reduce the film forming temperature of emulsion.
12. If the white latex product foam is more, can add an appropriate amount of defoaming agent.
13. The dosage and adding time of the initiator potassium persulfate should be carefully controlled. When reflux occurs, if the reflux is large, it indicates that the initiator has no effect and there are too many monomers, the initiator should be stopped. Some initiators can be added as appropriate, and monomers should be added when reflux is normal.
14. The white latex of Dongguan produced by the above formula and production method is a white uniform emulsion liquid with a solid content of about 50% and a pH value of about 5.
In addition, the dongguan white latex products can be added 801 glue, anatase titanium dioxide production of modified white latex.