Development Experiment Analysis of High-speed Cigarette Lap Gum

[Abstract] In order to prepare excellent high-speed cigarette styling adhesives, the polymerization of vinyl acetate-butyl acrylate-methacrylic acid copolymerization system was used for emulsion polymerization. The obtained product had the characteristics of fast drying, smooth paste, good stability, etc. The monomer ratio was VAC/BA/AA=3.5:1.4:0.1, the polymerization temperature was 82±1°C, the initiator dosage was 0.3% to 0.4%, and the pH was 5 to 6, the emulsion had the best performance.

Keywords: Cigarette glue; Lap-bond; Acrylate; Emulsion

Cigarette adhesives are divided into gusset glues, mouth glues, plastic bags, filter rod glues, and large box packing glues, among which the most critical ones are cigarette gluing. In order to make the cigarette roll seam smooth, no leakage run phenomenon, the use of adhesive tape must have strong initial adhesion, drying speed, high solid content, good fluidity. In the 1970s, the speed of cigarettes was 1,000 sticks/min. Most of the rubber used was modified starch glue.
With the development of the tobacco industry, cigarette speeds of cigarette makers are getting higher and higher, reaching 6,000-10,000 sticks/min. Original cigarette gluing for low-speed cigarette machines has fallen far short of the requirement. This requires that our country must The development of high-speed gutta percha. In recent years, many domestic companies have developed high-speed cigarette adhesives. The types of rubber used in different models are mainly polyvinyl acetate emulsion, vinyl acetate-ethylene (VAE) copolymer emulsion and vinyl acetate-butyl acrylate (VAB) copolymer emulsion. In this paper, a vinyl acetate-butyl acrylate-acrylic acid ternary copolymerization system was used to synthesize high-speed adhesive and the properties of the emulsion were tested. The results show that the emulsion has a high solid content, low viscosity, good fluidity, low temperature film formation.

1, the experimental part

1.1 The main raw materials

Ingredients: vinyl acetate, butyl acrylate, acrylic acid, polyvinyl alcohol. The above are industrial products.

Excipients: OP-10, ammonium persulfate, potassium persulfate, dibutyl phthalate, sodium acetate. The above are reagents.

1.2 Experimental Procedure

In a four-necked flask equipped with an electric stirrer and a reflux condenser, polyvinyl alcohol and water were added and dissolved by heating. A mixed monomer of VAC, BA, and AA in a total amount of about 30% to 40% of the total amount of monomers and a certain amount were added. The emulsifier is emulsified at a constant temperature of 50° C. for about 0.5 h, then the initiator is added in 5 batches, and the temperature is raised under stirring. When the temperature reaches 70-80° C., the remaining monomers and auxiliary materials are added dropwise, and the addition is completed. Insulation 1 ~ 2h. The temperature was gradually raised to 90°C to allow the unreacted monomers to fully react. When no reflux was confirmed, the mixture was stirred for 0.5 h while keeping warm. When the temperature began to drop and the temperature dropped below 50°C, an appropriate amount of NaHCO 3 was added to adjust the pH to 6.5, then a plasticizer, a polymerization inhibitor, etc. were added, and the mixture was evenly stirred and cooled to discharge.

1.3 Product Performance Testing

According to the provisions of GB-1175-89, the appearance, pH value, solid content, residual monomer and particle size of the product are tested.

2. Results and Discussion

2.1 Effect of Emulsifiers on Polymerization

The nature and amount of the emulsifier have a great influence on the particle size, stability and other properties of the copolymer emulsion. Anionic surfactants are used as emulsifiers and the resulting emulsions have poor stability. The emulsion prepared by using the non-ionic surfactant alone has good chemical stability to the electrolyte, but the milk is coarse, and the hard block is easily formed during polymerization, and the amount is large. Therefore, a complex emulsifier was used. In this experiment, the non-ionic surfactant OP-10 was used in an amount of 2.8% to 3.2% of the monomer; anionic sodium lauryl sulfate was used in an amount of 0.8% of the monomer. The results show that the system has good emulsification effect.

2.2 Influence of Initiators on Polymerization

Under the same experimental conditions, potassium persulfate reacts strongly and has poor solubility; ammonium persulfate reacts more steadily and dissolves easily. Therefore, this experiment uses a mixture of the two, each with half the ingredients. Experiments show that the amount of initiator is too small to initiate the reaction; the amount of the initiator is too intense to react, the molecular weight is small, and unstable, and the amount is preferably 0.3% to 0.4%.

2.3 Effect of pH on Emulsion Stability

During the polymerization process, the pH should be adjusted to the slightly acidic side to prevent hydrolysis of the monomer and adjust the reaction rate and temperature. After the termination of the polymerization, the emulsion should have a certain degree of mechanical stability, and the pH value has a direct effect on the stability of the emulsion, generally adjusted to 5-6.

2.4 Effect of Polyvinyl Alcohol on Product Performance

In the emulsion polymerization process, polyvinyl alcohol not only acts as a protective colloid and emulsifier, but also reacts with vinyl acetate, acrylates, etc. in part. Thus, the properties of polyvinyl alcohol directly affect the quality of the copolymer emulsion. Large amount of adding, latex viscosity is easy to thicken, not easy to spray from the nozzle; less dosage, low viscosity of the emulsion, less glue, poor adhesion, when cutting into small cigarettes, cigarettes Explosive mouth prone to produce defective products and waste products. The test found that in the emulsion polymerization of polyvinyl alcohol and low molecular emulsifier, the amount of polyvinyl alcohol used was 3% to 6% (relative to the total amount of monomers), and the obtained emulsion was most suitable for cigarette spray application. (to be continued)