Study on Modification of Polyvinyl Acetate Copolymer Adhesive (II)

Second, the results and discussion

Raw material ratio development

1Select the basis for polymerizing monomers

Different monomers have different characteristics. When selecting the polymer monomer, it can be selected according to actual needs. For example, vinyl acetate self-polymerized glue has good stability and excellent adhesion, but at the same time, due to the high glass transition temperature and poor film brightness and water resistance and cold resistance, the copolymerization of acrylate and vinyl acetate can reduce the content of polyvinyl acetate. The glass transition temperature improves the gloss, water resistance, and cold resistance of the coating film. With the introduction of the polar group acrylonitrile monomer, the viscosity of the polymer increases, the initial tack and dispersion properties can be improved, but the water resistance performance decreases. Also, after the acrylonitrile monomer is introduced, the polymer glue will have a color. Therefore, the polymer monomer species can be selected based on the actual requirements for the product.

2 The amount of polymerized monomers

1) Binary comonomer usage. The introduction of the comonomer acrylate can give the polymer excellent film brightness and water resistance, flexibility and cold resistance. Figure 1 shows the relationship between the mass ratio and the copolymer's water resistance when the other test conditions are unchanged and the total amount of acrylate and vinyl acetate is 110 g.

It can be seen from Fig. 1 that when the mass ratio of acrylate to vinyl acetate is 0.29:1D inch, the water resistance is 12 days, and the water resistance increases as the proportion increases, and the cost is greatly increased. When the ratio is 0.29:1, the brightness of the binary copolymer glue is also improved, and the other overall performance indicators are reduced. Considering the combination of cost and quality, the mass ratio of methyl acrylate to vinyl acetate is 0.20–1 0.29:1.

2) The amount of ternary comonomer. With the introduction of the polar group acrylonitrile monomer, the viscosity of the polymer increases, the initial tack and dispersion properties can be improved, but the water resistance performance decreases. Also, after the acrylonitrile monomer is introduced, the polymer glue will have a color. After a lot of experimental research, it was determined that the optimal amounts of vinyl acetate, acrylate and acrylonitrile were 80g, 10g and 5s respectively, that is, the best quality ratio was 16:2:1.

(to be continued)