Synthesis And Performance Of Polyurethane-Acrylates Composite Emulsion With Core-shell Structure

With the improvement of environment protection awareness, aqueous coating has been an important trend of coating development. Compared with other solvent products, polyurethane(PU) and polyacrylate with these advantages of low price and no poison, so has been utilized widely in coating, adhesion, leather, textile coat etc. Although acrylate emulsion has some advantages such as in higher mechanical strength, aging resistance, light resistance, water resistance, which is polymerized with free radicles and composed with various monomer random in the molecular chain, so it has these disadvantages in organic solvent resistance , toughness, wear-resisting resistance, chemical resistance, high temperature adhesiveness, low temperature brittleness. Polyurethane has excellent cold endurance, temperature adaptability, elasticity, solvent resistance, but has these disadvantages in water resistance, light resistance, self-thickening. The property of PU and PA are complementary, new latex combined with polyurethane and polyacrylate is the research focus home and abroad.In this paper, polyurethane-acrylates(PUA) composite emulsion with obvious core-shell structure was prepared by method of designing partical structure. On the basis, the effects ( such as different monomer, core-shell monomer ratio, the amount of PU, AA, initiator,emulsifier, acidity ,reaction temperature, the feeding method of shell monomer, etc.) on emulsion and film performance were studied. The reaction conditions of the emulsion were determined: the feeding method of shell monomer was starved semi-continuous; the mass ratio of core-shell monomer 1/1.25; the amount of PU 10%; the amount of KPS 0.7%; the amount of emulsifier 4%; reaction temperature 80±2℃. As a result, the emulsion with higher solid contents and lower viscosity was obtained. The contents of AA, which greatly affected on water-resistance and adhesive force of film, were 4% of gross monomers.It could form bright and transparent film in room temperature with good resisting viscidity and adhesive force of 0 grade,which didn't delaminate over a half-year period of storage Orthogonal experiments resulted that the film with good water-resistance, lower temperature and preferable adhesive.The morphology of emulsion particles was characterized by transmission electron microscopy (TEM), differential scanning calorimetry (DSC), infrared spectroscopy(IR), etc, which indicated that the core-shell particles were uniform in size but bigger than...