The Antibacterial Finishing Study In Yarn Used In Medical Graduated Compression Stockings

Lower extremity venous diseases namely lower limb venous insufficiency, whichincluding venous reflux and venous reflux disorder, and its most common clinicalmanifestations are lower limb varicose veins and lower limb venous thromboembolism.Treatment of lower limb varicose vein consists of conservative and surgical treatment.Medical graduated compression stockings (hereinafter referred to as MGCS) as aneffective conservative treatment, can greatly reduce the suffering and economic burdenof patients. Due to the special design principle, resulting in poor permeability andmoisture absorption, the long-wearing MGCS are easily lead to breed bacteria on theskin surface, expecially the sweating due to physical or environmental causes, can evencause skin diseases and wound infections during lower limb surgery convalescence. Butthe current researches of MGCS in domestic and foreign generally focus on structuraldesign, mechanical mechanism, medical efficacy and materials. There is few report inantibacterial of MGAC. So this issue is to explore the antibacterial finishing of spandex/nylon covered yarn used in MGCS, emphasis on finishing process, the antibacterialeffect and its relationship with mechanical properties of covered yarn using theantibacterial agents SCJ-891and SCJ-96that suitable to nylon.Firstly, this paper compares the characteristics of two standard curve methods ofantibacterial test, and comes up with a new antibacterial evaluation method. The studytests and draws the standard curve of Staphylococcus aureus(SA) and Escherichia coli(EC) based on turbidity by two methods, the standard curve of "semi-dilution" and"Time staircase method"of two kinds of bacterias are y=7.4101x(SA), y=34.184x(EC)and y=7.0316x(SA), y=33.773x(EC). From the fitting result, the fitting R2of "semi-dilution" is better than "Time staircase method". And then, the paper proposes a newantibacterial effect evaluation mechanism as an alternative to plate count method, themechanism has many advantages such as ease operating, short experimental period,good repeatability, etc., and the most important it can be used for large quantitiesantibacterial effect evaluation tests at the same time.Secondly, the paper studies the antibacterial effect of different levels of four factorswith two agents SCJ-891and SCJ-963through impregnation finishing and single-factorexperiments, the results show that the bath ratio, the amount of antibacterial agents, pHand the soaking time have varying degrees of impact to effect results, and the coveredyarn can get good antibacterial properties with each antibacterial agents.In order to find the optimal finishing experimental parameters combination, thispaper carries out a four-factors-three-levels orthogonal experiment with the result ofsingle-factor experiments and the scheme of L9(34), results show that:(1) The optimized parameters combination for antibacterial finishing of coveredyarns used in MGCS with SCJ-891is D3B3A2C, i.e. soaking time is60min,10%ofo.w.f and1:20of bath ratio and pH is4.5to6.5. The pH has no significant effect on theinhibition rate at the range of orthogonal.(2) The optimized parameters combination for antibacterial finishing of coveredyarns used in MGCS with SCJ-963is A2B2C2D1, i.e.bath ratio is1:20,6%of o.w.f, pHis5.5and soaking time is30min. At the orthogonal range, the bath ratio is extremely significant-impact on the index, the o.w.f and pH have a significant-impact on the indexand soaking time has no significance on the index.(3) All of four factors have no significantly affects on the index of tensileproperties of yarn. The decreasing of elastic recovery rate after finishing, mainly due tothe poor heat resistance of nylon. The finished yarns have a shrinkage occurs in hot andhumid conditions, so that influencing the cover properties and then elastic propertiesdeteriorate.To verify the optimal parameter combination, the subject has validated tests andfound that the sample produced with optimized parameters can indeed get betterantibacterial properties compare with a large proportion of former samples. Also foundthat the use of SCJ-891finished yarn’s antibacterial properties are slightly worse thanthe SCJ-963. Further antibacterial durability experiments show that the yarn with SCJ-891has a decreasing of washing-resistance after washed70times, but the yarn withSCJ-963keep a low fluctuation during the100times washing experiments.In summary, the use of SCJ-891and SCJ-963can indeed get a better covered yarnwith better antibacterial properties and washing resistance, but as an improved products,the SCJ-963have a good performance on the antibacterial effects and resistance towashing than SCJ-891. So that the paper recommends using the SCJ-963to finish thecoveres yarn used in MGCS, and the optimization finishing parameters are:1:20of bathratio,6%of o.w.f, pH=5.5and soaking time30min.