Study on Production of Low-toxic Adhesive for Plastic by Distillation of PVC Residual Liquid II

1.3 Experimental Procedure

1.3.1 Synthesis of Multi-component Copolymer Resins

According to the ratio of Table 2, the quality of the PVC residue distillate, vinyl acetate, and acrylate is weighed at 2/3, and then added to a 3-necked flask with a stirring and refluxing device, and then half the total amount of initiator is added. The water bath was heated to reflux temperature and reacted for about 4 h under reflux conditions. The remainder of the PVC residue was distilled to dissolve the remaining half of the initiator and then the remaining amount of vinyl acetate and acrylate was mixed, and then the reaction system was dribbled under reflux for 1.5-2 hours. After completion of the dropwise addition, the reaction was continued for 2-3 h. When the sample content and viscosity of the sample were determined to be acceptable, the temperature was lowered to 40° C. or less.

1.3.2 Preparation of Adhesives for Plastics

The tackifier resin is dissolved with an appropriate amount of the volatilization rate regulator, and after being mixed into the plasticizer, it is mixed with the multi-component copolymer resin glue solution to obtain a transparent plastic adhesive. If you need to bond a hard plastic with a large surface area, you can add a certain amount of filler, after adding the filler must be fully ground to homogenize the colloid.

1.3.3 Technical Specifications of Adhesives for Plastics

The specifications of plastics-specific adhesives are in line with Q/JSx01-2004 quality standards. The main technical indicators are shown in Table 4.

2 Results and Discussion

2.1 Synthetic principle and monomer selection of multi-component copolymer resin

Because the PVC raffinate distillate contains/are reactive monomers such as vinylidene chloride, but its proportion is relatively low, suitable amounts of vinyl acetate, acrylate and other reactive monomers are easily introduced into the PVC residue distillate to obtain easily soluble multi-component copolymerization after polymerization. The resin glue not only improves the solid content of the glue, but also greatly improves the application performance of the resin glue. Its synthesis has the following mechanism:

It can be seen that the multi-component copolymer resin is a mixture of a plurality of polymerization forms, and its molecular structure cannot be accurately shown. However, the polymerization conditions and the properties of the resin (eg, dissolution properties, viscosity, etc.) can be adjusted according to the type and amount of the active monomer. For example, if the initiator is added directly to the PVC lye, the glue solution is not obtained. When a suitable amount of vinyl nitrate and acrylate is added to the system, a viscous glue solution can be obtained as an initiator. Under the same conditions, if about 1% of acrylic acid is added to the system for copolymerization, the viscosity of the glue solution increases sharply, and the polymer resin has good solubility in ketones and ester solvents. When acrylonitrile is used instead of acrylic acid, the turbidity and precipitation of the copolymer resin glue liquid are prone to occur, and some mixed solvents must be used to dissolve completely. In production applications, the monomers and their amounts should be reasonably selected according to the application fields and performance requirements of the copolymers.

(to be continued)