Graft Modification Of Hyperbranched Polyesteramides With Blocked Isocyanates And It's Application

The preparation of pigment decentralized system and dyeing were involved in pigment dyeing, a large number of dyeing auxiliaries, including dispersants, emulsifying agents, adhesives, cross linking agents and so on. Furthermore, rubbing fastness of fabric dyed with pigment was poor. Developing versatility dyeing auxiliaries to improve fastness had become an important subject.The reaches for hyperbranched polyesteramides and blocked isocyanates were very popular at home and abroad, which be used in a variety of applications, less in pigment dyeing. Hydroxyl functional hyperbranched polyesteramides could be modified with blocked isocyanates to gain graft modified products which could disperse pigment and improve fastness. The graft products could be used as a versatility dyeing auxiliary to reduce other additive agents used, which were of great positive significance to reduce loading of environment and speed up the development of technology of pigment dyeing.In this work, hydrophilic chains were synthesized with toluene 2, 4-diisocyanate (TDI), and mono methoxy polyethylene glycol (MPEG), one–NCO of isocyanates were blocked use die thylene glycol monobutyl ether (DGME), methyl ethyl ketoxime (MEKO), caprolactam(CL) as block agents respectively to gain blocked isocyanates prepolymers. Hyperbranched polyesteramides were modified by grafting hydrophilic chain prepolymers and blocked isocycanates prepolymers to gain waterborne hyperbranched polyesteramides grafted blocked isocyanates (Hyperbranched Blocked Isocyanates, HBI). The yield (Y) and grafting efficiency (GE) of prepolymers were discussed. It was discussed that the effect of block agents, chain length of hydrophilic chain, molar ratio of intermediates, solvent and method of adding dropwise on solubility and fixation of HBI. The structure of intermediates and graft modified products were characterized by FT-IR and the particle size, solubility, solution stability were studied and compared. Thermal properties including the range of de-blocking temperature and extent of de-blocking reaction were researched by differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). The thermal analysis revealed that the graft modified products with MEKO as block agent started to de-block at about 148-158℃.Water-based ultra-fine pigment dispersions was prepared with HBI as dispersant, size of pigment reached to 208.5nm after ultrasonic dispersion 50min. When HBI was heated, then the blocking agents were diffused and evaporated to release free isocyanates to obtained reaction activity again. The new free isocyanates then reacted with nucleophiles such as hydroxide and other groups containing active hydrogen of fabrics, pigments, adhesives, which fixation particles of adhesives and pigments onto the surface of fabrics firmly to improve rubbing fastness. HBI used as a fixing agent, the soaping fastness reached to 4-5, dry fastness reached to 2,wet rubbing fastness reached to 2-3 after baking 3min at 160℃.