Preparation Of Soil And Oil Stained Test Stirps And Study Of Wash Property Of Stains

Intelligentization is the core tendency of the development of washing machine, whichshould be based upon the fully understanding of the law of stain removal. The stained teststrips, one of the most common samples for the evaluation of washing performance ofwashing machine, is the optimal choice for the exploration of the law of stain removal. Onlythree kinds of stained test strips, including the strips stained with carbon black/oil, protein andsebum test strips, are applied in Chinese standard, and a composited test strip, stained withsebum, carbon black/oil, cocoa, blood and wine, respectively, is used in the internationalstandard IEC60456, for the evaluation of washing performance of washing machine. As thecategories of standard stained test strips are limited, it is urgent to develop new stained teststrips based on stains existed in daily life for the exploration of the law of stain removal.In this paper, the preparation methods of test strips stained with soil and oil were studied.The preparation conditions of these two test strips were optimized, and the morphologicaldistribution of the stains were observed by SEM(scanning electron microscope). In addition,the evenness, storage stability and washing performance of the prepared stained test stripswere all evaluated. Orthogonal experiment was designed to explore the effects of washtemperature, wash time, water volume, wash speed and wash-stop ratio on the cleaning rate ofself-prepared and the IEC composited stained test strips.The results showed that stable dispersion solutions of carbon black and clay wereobtained, respectively, when the concentrations of dispersant paregal and sodiumhexametahposphate(SHMP) were both1.6%. The homogeneous soil solution, which was amixture of carbon black and clay dispersion solution, could be kept for24h at least. Stableoil/water emulsion was prepared when the HLB value was8, the concentration of emulsifierwas5%and the emulsifying time was6mins. The prepared oil/water emulsion could bestored for12h without break-up. The soil and oil were both coated on the fabric according toSEM. Besides, the soil covered on the surfaces of the fibers and the oil mainly existedbetween fibers. The self-made soil and oil stained strips showed excellent evenness, storagestability and washing performance.The washing experiment indicated that the influence factors on the cleaning rate of soilstained strips in whole load test was in the order of wash temperature>wash time>watervolume>wash speed>wash-stop ratio, while the influence factors on the cleaning rate of soilstained test strips in half load test was in the order of wash temperature>wash time>watervolume> wash-stop ratio> wash speed; In case of full load, the influence factors on thecleaning rate of oil stained test strips was in the order of wash temperature>washspeed>wash-stop ratio>wash time>water volume. While in case of half load, the influencefactors on the cleaning rate of oil stained test strips was in the order of washtemperature>wash-stop ratio>wash speed>water volume>wash time; The strip stained withcarbon black/oil had similar wash property when it was washed in case of half loaded and fullload. For the carbon black/oil stained fabric, the wash temperature had greatest effect, whilethe wash speed produced minimal effect on the cleaning rate; The influence factors on thecleaning rate of sebum stained test strips in case of full load was in the order of washtemperature>wash-stop ratio>wash time>water volume>wash speed. While order of wash temperature>wash-stop ratio>water volume>wash time>wash speed was obtained for halfload test; The blood stained test strip had similar wash property when washed in half load andfull load test; The wash temperature had greatest effect, while the water volume had minimaleffect on the cleaning rate of blood stained test fabric; In full load test, the influence factorson the cleaning rate of cocoa stained test strip was in the order of wash time>washtemperature>wash-stop ratio>wash speed>water volume. While half loaded, the influencefactors on the cleaning rate of cocoa stained test strip was in the order of wash-stopratio>wash time>wash temperature>water volume>wash speed; In full load, the influencefactors on the cleaning rate of wine stained strip was in the order of wash temperature>washtime>wash-stop ratio>wash speed>water volume. In half load, the influence factors on thecleaning rate of wine stained strip was in the order of wash temperature>wash time>watervolume>wash speed>wash-stop ratio.