Research Of High Performance Acrylic Pressure-sensitive Adhesive On Labels

Due to its excellent property of easy and safe production process, environmentally friendly, and good adhesive properties, the acrylic latex pressure sensitive adhesive(PSA) had recently been focused on especially in label PSA markets. Currently, the PSA based labels in domestic market have disadvantages such as low coating speed, poor wettability with non-polar materials, low peel strength, unsatisfactory heat and aging resistance etc. In order to solve these weaknesses, a kind of silicone modified acrylic emulsion is prepared with seeding semi-continuous emulsion polymerization which can meet mass production requirements.During the experiment of emulsion synthesis, the effects of emulsifier system and content, Tg, polar monomer content and buffer content on the emulsion properties and PSA adhesion qualities had been studied. The conclusion shows that when m(BA):m(EHA):m(MMA)=66:16.5:10, the Tg of the copolymer is-44.8 ℃; The APEO-free emulsifier system is constructed with AS-801 and COPS-1, which was 1.5% of monomer total mass; functional monomer m(β-CEA)=2.5%, m( HEA) =5%; When buffer m(Na HCO3)=0.25%, the synthetic emulsion shows out excellent stability and moderate viscosity.Compared with DAAM+ADH room temperature self-crosslinking system, the silane coupling agent crossing system have the advantage of having cross-linking reaction in emulsion synthesis, generating acting force with substrate, reducing the surface tension, so modified acrylic emulsion is used as silane coupling agent. It is discovered that the specie of silane coupling agent, the mean of adding and the dosage of silane coupling agent can affect the polymerzation and the property of the emulsion while chain transfer agent(CTA) only affect the property. When m(KH-572)=1.5%, m(DDM)=0.09%, the solid content of the emulsion is 55%, with good stability. The initial bonding strength is 16# steel ball; the 180° peel strength is 7.3N/25mm; its endurance bonding strength can lasts for more than 48 hrs with moderate wettability on release paper.The FTIR test result shows that, the acrylic emulsion of modified silane coupling agent had been produced and this reaction can reach completion. When analyzed by Malvern laser particle size analyzer, its average particle size is 340 nm, with a narrow distribution; the viscosity of the emulsion is 140cps; TG analysis has proved that the silicone modified acrylic emulsion has better heat resistance and aging property than acrylic latex.