Development of Waste Styrofoam Modified Emulsion Adhesive III

  The amount of modifier added must be appropriate to the amount of polystyrene in order to increase its polarity, can not be added too much, otherwise it will not be conducive to the dispersion of the adhesive, affecting the adhesive effect. The data shows that in the 30% polystyrene glue solution, when the rosin-modified phenolic resin is added in an amount of 1.5% to 4.0% of the mass of the polystyrene glue, the amount of the petroleum resin is polystyrene rubber. Liquid quality of 1.7% -3.3%, the resulting product better adhesion.

2.3 Emulsifier Selection

The key to determining the type and stability of the emulsion is the nature of the emulsifier. Selecting the emulsifier according to the specific system to be emulsified should follow the following two principles: the Bancroft rule and the HLB value. Sodium lauryl sulfate and OP-10 emulsifiers are used as emulsifiers. Sodium lauryl sulfate has excellent properties such as foaming and emulsification. It is an anionic surfactant and OP-10 emulsifier. The agent has good emulsifying, wetting, dispersing, decontamination and antistatic capabilities, good anti-hard water performance, acid resistance and alkali resistance, and can be mixed with various surface activities. The mass ratio of the two is 2:1 and the total dosage is 2%-3%.

2.4 Stabilizers, Crosslinkers, Fillers

80l glue is added as a stabilizer to make the adhesive have a good penetration, increase the polarity of the adhesive, reduce the activity of the adhesive, and extend the service life of the adhesive.

Crosslinkers can form chemical bonds between macromolecules, either linear or branched polymer macromolecules. They play a major role in the modification of adhesives, and can improve adhesion strength, heat resistance, water resistance, chemical resistance, creep resistance, Aging resistance. The selected cross-linking agent should not affect the performance of the mouth, no poison, no irritation, no environmental pollution, low price, easy to accept, stable storage, and no condensation of the adhesive during the second storage period.

As a filler can reduce the shrinkage rate of the curing process, but also can give some special properties of the adhesive to meet the requirements of the use, in addition to some fillers. It will also reduce the heat release during the curing process, improve the resistance of the adhesive layer, the mid-tread toughness and other mechanical strength. Zinc oxide was selected as the cross-linking agent and filler, and the amount used was 5%-6%.

2.5 Effect of Emulsion Mechanical Equipment on Adhesion Performance

Emulsion preparation is divided into two methods: mechanical dispersion and self-emulsification. Whether the mechanical force meets the requirements and whether the dispersion capacity of the emulsifying equipment meets the requirements, it largely determines whether the emulsification effect is satisfactory and whether the emulsion is stable. The viscosity of the system to be emulsified in this experiment is relatively large, requiring the use of an emulsifying shear. If a conventional stirrer is used, the required mechanical force for emulsification cannot be achieved, resulting in a poor emulsifying effect. The diameter of the latex particles is too large, and the adhesive cannot penetrate into the pores of the adherend well, so that the bonding effect is not good, and milky Liquid product performance is unstable and delamination occurs.

2.6 Effect of Reaction Temperature and Time on Adhesion Properties

Under normal temperature, benzoyl peroxide does not decompose, that is, no free radicals are generated. Other modifiers may not react with polystyrene. Therefore, adhesives prepared at room temperature have poor adhesive properties and the adhesive layer is relatively brittle. Due to the low boiling point of the selected organic solvent, the volatilization is severe at higher temperatures. The degradation reaction of polystyrene at high temperature is intensified, and the resulting dried solids of the adhesive are easy to soften, and have a darker color and are liable to contaminate the adherend. Experiments show that when the modification reaction is performed, the reaction temperature is preferably 80°C. In the emulsification reaction, the reaction temperature is preferably 70°C because the performance of the nonionic surfactant changes when the temperature is high.

The adhesive strength of the adhesive increases with the reaction time, but when the graft modification time is greater than 3 hours and the emulsification time is greater than 2 hours, the adhesive strength of the adhesive does not increase significantly. Because after 3 hours of modification, the benzoyl peroxide was almost consumed, the graft modification reaction was basically completed, and after the emulsion was treated for 2 hours, the solvent was basically removed and completely recovered.

3 Conclusion

The main raw material of the adhesive is taken from the waste of the packaging industry, and the prepared product can be used in a large amount in the packaging industry, thereby greatly reducing production costs and transportation costs, while protecting the environment and reducing white pollution. Compared with traditional carton adhesives (such as: starch, PVA, white latex, etc.), it has good product stability, high adhesiveness, low cost, good performance, and also has good waterproof, moisture and corrosion resistance Sex, more versatile than similar adhesives, suitable for bonding of wood, paper and other packaging materials

(Author/Chen Zhongyuan, Qian Xiaozhong, Hu Jing Pan Xiangjun, Lu Liang)
"Packaging Project"