A solvent-free polyurethane adhesive for semi-high temperature resistant and high temperature cooking flexible packaging

Abstract

The invention relates to the technical field related to polyurethane adhesives. More specifically, the invention provides a solvent-free polyurethane adhesive for semi-high temperature resistant and high-temperature cooking flexible packaging. The preparation raw materials include A component and B component, A component Including the first component polyester polyol, the first component polyether polyol and isocyanate; B component includes the second component polyester polyol and the second component polyether polyol; and the polyol of the first component The number average molecular weight of the ester polyol is greater than that of the polyester polyol of the second component, and the weight ratio of the A component to the B component is 1: (0.3-0.9). The polyurethane adhesive provided by the invention avoids the peeling strength reduction or delamination of the composite material after high-temperature cooking, and can also effectively reduce the presence of bubbles or white spots in the composite structure obtained. During the preparation of aluminum foil composite materials, the problem of glue leakage will occur.

Description

technical field [0001] The invention relates to the technical field related to polyurethane adhesives. More specifically, the invention provides a solvent-free polyurethane adhesive for semi-high temperature resistant and high-temperature cooking soft packaging. Background technique [0002] Retort packaging is one of the fastest growing packaging categories at present. Retort-resistant packaging bags, commonly known as soft cans, are most notable for their long-term storage at room temperature without spoilage; they are also very convenient to use, and can be eaten cold or cooked hot. At present, retort bags are mainly used for packaging canned food, cooked food, etc., and are also used for packaging beverages, juices, mashed potatoes, cereals, etc. in Japan and Western Europe. With the improvement of people's living standards, my country's food packaging safety requirements are getting higher and higher, and solvent-free adhesives have a crucial impact on the usability of...

AI Technical Summary

Problems solved by technology

[0003] In the process of material compounding and use, solvent-free adhesives do not produce toxic gases, and there is no hazard of toxic solvent residues such as food and medicine. However, in the actual application process, solvent-free adhesives also have some defects. For example, after high-temperature cooking, the peel strength of the composite material decreases or delamination occurs, and there are also bubbles in the resulting composite structure. Or white spots, or in the process of preparing composite materials containing aluminum foil, there will be glue leakage problems, etc., it is difficult to achieve a solvent-free adhesive that avoids these problems in the prior art

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