Water-based plastic-plastic compound adhesive for food and drug flexible package and preparation method thereof

Abstract

The invention discloses a water-based plastic-plastic compound adhesive for food and drug flexible packages and a preparation method thereof. The preparation method comprises the following steps of: carrying out pre-emulsification by using 20-30 parts by weight of deionized water, 0.4-1.0 part by weight of emulsifying agents and 75-90 parts by weight of monomer mixtures to obtain a pre-emulsion A; then carrying out the pre-emulsification by using 5-8 parts by weight of the deionized water, 0.2-0.3 part of the emulsifying agents and 3-20 parts by weight of the monomer mixtures to obtain a pre-emulsion B; preparing an initiator water solution C by using 1-3 parts by weight of the deionized water and 0.2-0.8 part by weight of initiators; and dropping the monomer mixture I with lower polarity and the monomer mixture II with higher polarity step by step by adopting a pre-emulsification seed emulsion polymerization process to obtain the water-based plastic-plastic compound adhesive for the food and drug flexible packages. The water-based plastic-plastic compound adhesive disclosed by the invention has the advantages of no organic solvent, no formaldehyde release, good adhesivity and high stripping strength and permanent adhesion and can be applied to a flexible package industry and substitute for a solvent type two-component polyurethane adhesive maturely applied to the present market.

Description

technical field [0001] This patent relates to a composite adhesive, especially a water-based plastic-plastic composite adhesive suitable for flexible packaging of food and medicine and its preparation method. Background technique [0002] Plastic-plastic composite packaging materials for food and drug flexible packaging mainly adopt the dry laminating method, that is, a laminating machine is used to coat a layer of adhesive on the plastic film, and then the solvent or moisture in the adhesive is removed through a drying tunnel, and then hot-pressed. combine. Commercially available adhesives are mainly solvent-based (such as two-component polyurethane) and water-emulsion-based. Solvent-based laminating adhesives have a serious impact on human health and the environment, and are not convenient for storage and transportation, and are facing elimination. The water-based adhesive uses water as the dispersion medium, has low cost, and has no residual solvent, which meets the env...

AI Technical Summary

Problems solved by technology

Compared with the products of companies such as Rohm and Haas, domestic acrylic water-based laminating adhesives still lack technical competitiveness and have many technical defects: poor wetting performance for plastic films with low surface energy; Due to the interfacial migration effect of molecular substances, its peel strength and holding force are far inferior to those of solvent-based products, and its water resistance is poor; it is easy to foam during the coating process on the machine, and the drying speed is slow, so it cannot be coated at high speed; it can withstand high temperature and high humidity environment The performance is poor, and it cannot meet the application requirements of cooking-resistant food packaging

In order to improve the application quality of water-based adhesives, some modified cross-linking agents have been developed in recent years, such as polyfunctional ethyleneamine, polyfunctional carbodiimide, polyfunctional aziridine, polyfunctional oxazoline, vinyl siloxane , to improve the performance of water-based laminating adhesive, but there are problems such as high crosslinking temperature and slow speed, and the two-component packaging form is not convenient for storage and transportation

The introduction of DAAM / ADH room temperature cross-linking system can improve the storage stability of the emulsion, but it will have a certain negative impact on the cohesive strength of the film

Images