| Thermoplastic elastomer pressure sensitive adhesives are widely used in various m edical fields such as ostomy structure,and has broad market application prospects,for its good initial viscosity,good biocompatibility,and no pollution and solvent-free parti cipation in the production process.However the current pressure sensitive adhesive use d for ostomy bag exists such problems:(1)Integrity cannot be maintained after the a bsorption of wound permeation fluid;(2)The adhesive failure mechanism under wet e nvironment hasn’t been explored;(3)It shows poor adhesion performance after the ab sorption of wound permeation fluid.The subject of the study has been divided into three parts:(1)The adhesive fail ure mechanism under wet environment of the ostomy pressure sensitive adhesives was explored.Based on the above mechanism,this paper adopted the single variable metho d to analyze the effect of different hydrophilic molecules on bonding properties and m oisture absorption performance of pressure sensitive adhesive.(2)The fluid handling capacity of the ostomy pressure sensitive adhesive needed to be maintained at about 5000g/(24h·m2),but the current pressure sensitive adhesive cannot maintain the structura 1 integrity under the fluid handling capacity.This paper optimized the formulation to i mprove the integrity of the ostomy pressure sensitive adhesive after moisture absorptio n,and the effect of styrene-isoprene-styrene,tackifying resin and naphthenic oil on the integrity of the pressure sensitive adhesive was studied by orthogonal experiments.(3)The method of electron beam irradiation was introduced to crosslink the pressure sensi tive adhesive,and the effect of irradiation dose on the performance(mechanical,hygro scopic,and cytotoxic)of the ostomy pressure sensitive adhesives was explored,as wel 1 as the optimal irradiation dose.It was found that(1)the reason of adhesive failure was mainly related to the p erformance of the hydrophilic component.Due to the expansion of the hydrophilic co mponent,the continuous phase matrix was squeezed.So the effective bonding area wa s reduced,and the adhesion failure occured.Moreover,after the moisture absorption,a part of hydrophilic component escaped from the pressure sensitive adhesive,forming a new interface between the pressure sensitive adhesive and the steel plate,which red uced the adhesive force.(2)hydrophilic molecules had a certain influence on the ad hesive properties of pressure sensitive adhesives.While the hydrophilic molecule was s uperabsorbent resin,pressure-sensitive adhesive processed the highest peel strength and holding power.In terms of moisture absorption,the highest moisture absorption rate w as found in a pressure-sensitive adhesive which included Sodium carboxymethyl cellulo se or superabsorbent resin as hydrophilic molecules,as well as the highest moisture a bsorption in 24 hours.Pressure sensitive adhesives containing pectin or cross-linked ca rboxymethyl cellulose can retain certain adhesive properties after moisture absorption.(3)The content of thermoplastic elastomer styrene-isoprene-styrene was the most imp ortant factor of the integrity of the pressure-sensitive adhesive.It was found that The optimal ratio of the continuous phase matrix,namely,styrene-isoprene-styrene:Petroleu m resin:Naphthenic oil:terpene resin is 12:15:2:5.At this time,the pressure-sensitive adhesive had the best performance.(4)With increasing irradiation dose,the mechani cal properties,water-absorption abilities,and cytotoxicity of pressure-sensitive adhesives increased first and then decreased.The optimal irradiation dose was 3.5 Mrad.At thi s time,the pressure-sensitive adhesive maintained excellent adhesion performance(The 180° peel strength can reach 0.99kN/m)and good integrity(integrity ratio can reach 95%).This paper basically solves the problem of poor adhesion and integrity after moistu re absorption,which provides a theoretical basis for the design in the industrial produ ction and makes it more widely used in the medical field. |
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