| Summary: | 碩士 === 明志科技大學 === 化學工程系生化工程碩士班 === 106 === Blocked isocyanates means that highly reactive isocyanates (-NCO groups) are protected by a protecting group (blocking reaction) to attenuate their high reactivity, while deprotection is carried out at higher temperatures (unblocking) Reaction) to expose a blocked compound which is highly reactive with isocyanate. . Closed isocyanates are widely used in one-component coatings, such as electrical insulating varnishes made of blocked isocyanates with good electrical insulation, water resistance, solvent resistance and good mechanical properties; blocked isocyanates are also in powder coatings. There are important application values. Some new sealants have been commercialized and some new applications have been developed. Closed isocyanates are used in adhesives to increase their stability and shelf life. They are mainly used in synthetic fabrics and rubbers. Bonding. In addition, blocked isocyanates are also widely used in aqueous polyurethanes, which have the characteristics of low film formation temperature and good film properties. In summary, the use of blocked isocyanates is becoming more widespread, and it is gradually transitioning from solvent to aqueous.
The 4,4-isocyanate diphenylmethane (MDI) used in this study is an important isocyanate, mainly used in the preparation of polyurethane elastomers, polyurethane coatings, etc., in aerospace, construction, vehicle, ship, refrigeration and furniture sectors. Wide range of applications. In order to enhance the covalent bonding force of the synthesized blocked compound with carbon fiber and resin, the water-soluble Resorcinol (adhesive A) and N-methylaniline (adhesive B) were used as protective groups to block the diphenylmethane. The active nature of the diisocyanate and the analysis of the strength and stress of the drawn body using carbon fiber as a test to understand the utility of the test synthesis of the blocked compound. The bridging agent corresponding to the design of the original process allows the screw industry to paint with the use of aqueous slurry to improve the shortcomings of electroplating and organic coatings.
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