How Polyether Polyols for Adhesive Are Revolutionizing Various Industries With Their Exceptional Properties 3?
There are also many other applications:
3. Footwear Polyurethane Adhesives:
- China is a major shoe manufacturer. After three generations of development, with increasing global environmental awareness and an intensified oil crisis, the fourth generation of environmentally friendly solvent-free and water-based shoe adhesives emerged. The preparation technology for water-based polyurethanes has become increasingly mature. For some low-polarity shoe materials like SBS, the peel strength of polyurethane adhesives does not meet the requirements. By adding tackifying resins and other modifications, it is possible to develop polyurethane shoe adhesives with high crystallinity, fast crystallization speed, high cohesive strength, and ideal peel strength.
4. Packaging Polyurethane Adhesives:
- Flexible packaging, also known as soft canning, has surpassed rigid packaging such as plastic, glass bottles, and cans due to its light weight, convenience, long shelf life, hygiene, ease of storage and transport, easy opening, minimal waste, and excellent shelf appeal. Polyurethane adhesives, due to their superior performance, can bond different film materials together to obtain composite films with properties such as cold resistance, oil resistance, drug resistance, transparency, and abrasion resistance, making them the primary adhesives for processing composite films for flexible packaging in both domestic and international markets. In the domestic adhesive market, the consumption of polyurethane adhesives in the flexible packaging industry ranks second only to the shoe industry. There are numerous types of polyurethane adhesives for packaging, such as water-based polyurethane adhesives, hot-melt polyurethane adhesives, solvent-based polyurethane adhesives, and solvent-free polyurethane adhesives. Commonly used polyurethane hot-melt adhesives can be divided into two types:
(1) thermoplastic polyurethane elastomer hot-melt adhesives and (2) reactive hot-melt adhesives. The main disadvantage of thermoplastic hot-melt adhesives is their high viscosity, which significantly affects the coating's appearance. Reactive polyurethane hot-melt adhesives are a new type of adhesive developed from traditional hot-melt adhesives, combining the initial tack of traditional hot-melt adhesives with the excellent post-curing properties of polyurethanes, and offering excellent bonding performance to various substrates. In the field of water-based polyurethane adhesives for packaging, the use of emulsifiers or the introduction of hydrophilic ionic groups in molecules reduces water resistance, making research to improve water resistance a hotspot. Additionally, due to water's high heat capacity, improving the solid content to enhance drying speed is an urgent issue.