What are the performance characteristics of waterborne polyurethane adhesive?
The research of waterborne polyurethane adhesive began in the 1950 s, and it was in the 60 s and 70 s that people really paid attention to. However, the adhesive strength of waterborne polyurethane adhesive at that time was not high, and it was mostly used for packaging adhesive and some occasions with low adhesive strength. In the mid-1970s, water-based polyurethane adhesives used for bonding soles began to appear. Due to poor performance and lack of strict environmental protection regulations, by the end of the 1980 s, they were basically still in the experimental stage. In the early 1990 s, environmental regulations in Europe and the United States became increasingly stringent, and the VOC content of shoe factories began to be controlled.
waterborne polyurethane adhesiveWater as the main medium, does not contain or only contains a small amount of organic solvents. According to different formulations and additives, can be formulated into coatings, adhesives and other treatment agents. Compared with solvent-based polyurethane, it has the following characteristics:
Performance Characteristics of Waterborne Polyurethane Adhesive
1. Most waterborne polyurethane adhesives are solvent-free, odorless, non-polluting, and have the advantages of non-combustible and low cost.
2, most of the one-component waterborne polyurethane products do not contain NCO groups, mainly by the polar groups in the molecule to produce cohesion and adhesion, moisture volatilization after curing. Waterborne polyurethane contains carboxyl, hydroxyl and other groups, can also be introduced into other active groups, under appropriate conditions to participate in the reaction, so that the resin cross-linked. Add crosslinking agent (curing agent) to form a two-component system.
3. The main factors affecting the viscosity of waterborne polyurethane adhesive are emulsion particle size, ionic charge properties and quantity, etc. When the solid content is the same, the viscosity of waterborne polyurethane is smaller than that of solvent-based polyurethane.
4. Because the volatility of water is worse than that of organic solvents, the aqueous polyurethane glue dries slowly, and because of the large surface tension of water, the wettability of the surface hydrophobic substrate is poor.
5. It can be mixed with a variety of water-based resins to improve performance or reduce costs. Solvent-based polyurethanes can only be used with a limited number of other resins due to compatibility between polymers or solubility in certain solvents. Resin mixing.
6, the product taste is small, can be diluted with water, simple operation, easy to clean; and solvent-based polyurethane sometimes need to consume a lot of solvent in the process of use, especially two-component materials and glue is not as good as water-based glue. Convenient.
The research of waterborne polyurethane adhesive began in the 1950 s, and it was in the 60 s and 70 s that people really paid attention to. However, the adhesive strength of waterborne polyurethane adhesive at that time was not high, and it was mostly used for packaging adhesive and some occasions with low adhesive strength. In the mid-1970s, water-based polyurethane adhesives used for bonding soles began to appear. Due to poor performance and lack of strict environmental protection regulations, by the end of the 1980 s, they were basically still in the experimental stage. In the early 1990 s, environmental regulations in Europe and the United States became increasingly stringent, and the VOC content of shoe factories began to be controlled. The research on the synthesis and application of waterborne polyurethane dispersions was strengthened. The performance of waterborne polyurethane adhesives can basically meet the requirements of shoe making.
Water-based polyurethane adhesive for leather shoes lags behind sneaker. The reasons are roughly as follows: sneaker soles are basically new materials with relatively uniform material quality, and the sneaker factory is large in scale, with excellent personnel quality and equipment level in the shoe industry. However, the leather sole is made of complex materials, which makes it difficult to ensure that all new materials are used. The scale is small. Leather shoe products emphasize personalization. Even the products produced by large factories are not as large as large as large as sneaker products.
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