Preparation Of Flame Retardant Silicone-Acrylic Adhesive And Application In Electrostatic Flocking

The electrostatic flocking is the process that the villus is implanted onto the surface of the substrate under the action of high voltage electrostatic field.The acrylic adhesives are widely used in textile industry.However,the polyacrylate is flammable,which brings safety problems in practical application.Therefore,it is very important to prepare acrylate adhesive with flame retardant properties.In this paper,the phosphorus-containing silicone-acrylic emulsion is prepared by introducing the flame retardant monomer and silicon monomer to the molecular chain of acrylic ester.Subsequently,the flame retardant silicone-acrylic adhesive is prepared and used in the flocking process by blending and modifying the phosphorus-containing silicone-acrylic emulsion with aluminum hydroxide.The main work are as follows:?1?.The type and ratio of the reaction monomer,reaction temperature,the dosage of emulsifier,initiator,methacrylate alkoxy phosphate?PAM-100?and NaHCO₃ and the ratio of anionic/nonionic emulsifier are investigated by designing the single factor experiment.The conversion of monomer and the cohesion,stability and particle size of the latex are studied in detail.Finally,the optimal preparation method of phosphorus-containing silicone-acrylic emulsion is defined with the monomer ratio?BA/EA/MMA/PAM-100=55/25/15/5?,polymerization temperature?85°C?,the dosage of emulsifier?4%?,the ratio of anionic/nonionic emulsifier?3:2?,the amount of initiator?0.4%?,the amount of PAM-100?5%?and the amount of NaHCO₃?1%?.?2?.Fourier transform infrared?FTIR?,transmission electron microscope?TEM?,thermo-gravimetric analysis?TG?and differential scanning calorimeter?DSC?analyses are employed to investigate the structures and properties of the prepared emulsion.The results show that the emulsion gains the core-shell structure with the uniform particle size distribution and the average particle size of 168.1 nm.The monomers PAM-100 and vinyl silicone oil are successfully co-polymerized with each acrylic monomer.Only one glass transition temperature appears in DSC curve,and the actual test value?-28.44°C?is consistent with the theoretical value?-29°C?.The heat resistance of the phosphorus-containing silicone-acrylic emulsion film is improved up to 69.56°C compared to the industrial silicone-acrylic emulsion film of that.?3?.The flame retardant silicone-acrylic adhesive is prepared by blending the phosphorus-containing silicone-acrylic emulsion with inorganic flame retardant Al?OH?₃.The effect of the adding amount of Al?OH?₃ on flame retardant property of the adhesive is investigated.The flame retardancy property is measured by UL-94 flame retardant testing.Before adding Al?OH?₃,the phosphorus-containing silicone-acrylic emulsion film burns out within 10 s while the industrial silicone-acrylic emulsion film burns up within 3 s.The flame retardancy of phosphorus-containing silicone-acrylic emulsion is better than that of industrial silicone-acrylic emulsion.When the adding amount of Al?OH?₃ is 50%,the industrial silicone-acrylic emulsion has no rating for its burning off while the the phosphorus-containing silicone-acrylic emulsion shows the V-1 rating;when the adding amount of Al?OH?₃ is 100%,the phosphorus-containing silicone-acrylic emulsion can not be ignited while the industrial adhesive gains the V-0 rating.The results indicate the flame retardant silicone-acrylic adhesive obtains a better flame retardancy than the industrial adhesive under same amount of inorganic flame retardant.?4?.The flame retardant silicone-acrylic adhesive is used in the electrostatic flocking process.The effect of the amount of sizing,baking time and temperature and vary addition of Al?OH?₃ to the electrostatic flocking product is investigated by designing single factor experiment.The bending length,hand feel and flocking fastness are measured.The optimum process suited for electrostatic flocking is defined:sizing amount?250 g/m²?,baking temperature?100°C?,baking time?5 min?,flame retardant dosage?50%¹00%?.The flocking substrate,adhesive and fluff of the obtained flocked fabric are well combined.All the experimental results,including the flocking fastness?higher than 9000 times?,the bending length?2.6 cm?,the soft hand?3-4 level?,the dry rubbing fastness?4 level?,and the wet rubbing fastness?3⁴ level?,reach the standard of the first grade of electrostatic flocking home textile products.