Effect of Inclined Water Jets on Tensile Strength of Bicomponent Hydroentangled Nonwoven Fabrics

Joumal of Donghua University (Eng. Ed.) Vol.24. No.3 (2007) 4 13Effect of Inclined Water Jets on Tensile Strength of BicomponentHydroentangled Nonwoven FabricsMBWANA Suleiman Ndaro, JIN Xiang-yu(靳向煜), CHEN Ting(陈廷), YU Chong-wen (郁崇文)College of Tertiles, Donghua University, Shanghai 201620, ChinaAstract: The efects of inclined water jets on bicomponentydroentanglement efficiencyu. Many works have been donehydroentangled fabrics were investigated. The PET/COPETby reserches'1-1-]-1) to improve the flow charusterstics ofand PA6/PET hydroentangled fabrics were made by usingwater jets， which gives impact on the increase ofdesigned inclined water jet apparatus. Effects of basishydroentangled fabrics strength. Hwo C C and Shiffler Dweight, water jets inclination angle and water jet pressureA[I4 conducted the study on the mechanical properties ofwere discussed. The comparison was made o the averagepolytrimethylene terephthalete ( PTT ) hydroentangledtensile strength of fabrics made by perpendicular water jetsbonded fabrics and they concluded that break strength,(0° inclination angle) and inclined water jets of 20° withbreak elongation, tear strength have been developed atpressure levels of 3 bars and 7 bars. It was found thatvery low specific energy levels at 40 kJ/kg due to finenessincreases of water jet pressure, the fabrics tensile strengthof PTT fiber. Berkalp 0 B, Pourdeyimi B, and Seyami Awere increased. Furthermore, increases of water jets[15] made a study on texturing of the polyesterinclination angle, fabric tensile strength of 60 g/m2 fabricshydroentangled fabrics and concluded that water jetdecreased while for 100 g/m2 fabrics tensile strengthpressure has a marked effect and there are optimumincreased.pressures, passes, and energy to be considered duringKey words: inclined wuter jets; tensile strength ; hyxlrvemungledhydroentanglement. However studies mentioned abovefabrics; pie segmented fibers; isuands- in - the - seu fiberswere used perpendicular vertical water jets. Recently, withCLC number; TS 174.1 Document code: Athe high quality， diversity of fiber products, anddevelopment of nonwovens applications demand forArticle ID: 1672 - 5220(2007)03 - 0413- 06bicomponent fibers in the fields of synthetic fibers and non-woven fabrics have been increasing. While previousIntroductionresearch addressed the effect of pressure, specific energy,forming wire and web velocity on fabric performance nowork in public domain has been reported in the use ofHydroentanglement is basically an energy transfer processand water jets are acting perpendicularly to the fiber web.inclined water jets for hydroentanglement of bicomponentfibers. In this study we have tested the tensile strength ofHigh velocity water jets insert fibers from the surface into thehydroentangled fabrics and make a comparison betweenbodly of the fibrous web and entangle the inserted fibers aroundother fibers and themselves due to local turbulent energyfabrics produced by perpendicular and inclined water jets.To attain this goal the inclined water jet apparatus wasreleased by the deflection and interruption of the jets [1-5]。Theorigin of hydroentanglement technique dutes back to the latedesigned and used to make hydroentangled nonwovenfabrics.1960's when DuPont showed samples of their proprietary workdone in their research center.In 1974 DuPont launched their first hydroentanglementExperimentalproduction line in Tennessee of USA1L148]. Hydroentangledfabrics are being characterized by relatively high strength,1.1 MaterialThe fibers used in this study were islands in-the-seasoftness, drape, conformability and aesthetic closelyapproaching woven and knitted fabrisl-.,0]. The strengthbicomponent fiber (70% PET/30% COPET) of 37 PETof hydroentangled nonwovens depends on fiber types andislands and linear density of 4 dtex and the second is pietheir properties, web formation, web consolidation ansegmented bicomponent fiber (70% PA6/30% PET) of 8finishing technique while their weakness are due to bondsegments and linear density of 2.77 dtex.failure, fiber rupture and fiber sippag.1.3.10. Tensile1.2 Preparation of carded fiber websstrength has been considered to be the main property forThe_ carded webs. were. produced using conventionalhydroentangled fabrics and it has been used as a measure of samp中国煤化工amples were weighedTYHCNMHGReceived date; 2006- 06 -21.Biography: Mbwana Sulciman Ndaro, male, Ph. D Candidate, E-mail: mbwanasul @ yahoo. co. uk414Joumal of Donghua University (Eng. Ed.) Vol. 24, No.3 (2007)for attaining the target of 60 g/m2 and 100 g/m2 beforethe preparation of hydroentiangled non-woven fabricstreated with antistatic agent and the gentle opening ofshown in Fig. 1. The combinations of pressure levels of 3fibers samples by hands was performed first, the openedand 7 bars with jets of inclination anglesof0" and 20^ wereweighed fiber samples were processed in carding machineused during manufacturing of hydroentangled fabrics.and the webs were created. A number of layers were laidThe water was forced through the small manifoldon top of one another to get the necessary weight. Thewhere the constricted water jets were obtained through thesamplcs of fiber webs obtained were in the range ofjet plate having small nozzle orifices of round in shape with250 mm (width) x 770 mm (length).cone down configuration to avoid cavitation problems. The1.3 Preparation of hydroentangled nonwoven fabricsexample of the jet plate with nozzle orifices used in thisThe designed inclined water jet apparatus was used forstudy and its geometry dimensions is shown in Fig.2.Flow meter) Pressure gageirh业Valve 3Air compressorir, Valve 2Hose pipeValve I岳City waterWaterWater tank| Small manifldJet plateWater jetsI Fiber web supportTank supporValve 4ClampFig.1 Assembly of designed inclined water jet apparatus400( 20°_A-A|43.256φ5015°7x中0.3φφ由如由由白中国煤化工MHCNMHGFig.2 Jet plate of nozzle orifices of 20 angle of inclinationNote: All dimensions are in millimeters (mm) and the figure is not drawn to scale.Joumal of Donghua University (Eng. Ed.) Vol.24. No.3 (2007) 415In the small manifold the fabric size of 120 meshes wasobtaineu from five meisurements in each case.installed inside for the filtration purposes. Hydraulicaccessories such as pressure gauge, hydraulic hose, valves2 Results and Discussionand flow meter were used for pressure measurement, watertransport, as well as fluid control. The water jets wereBicomponent fibers can be generally categorized intobeing forced through the orifices and striking the fiber webfour groups; splittable fibers, mixed fibers, sheath/core,fixed on the screen mesh not shown on Fig. 1. The jet plateand side by side fibers. Bicomponent fibers create thewas small therefore the shifting of the fiber web in thepossibility for utilizing the properties of two polymers atcrosswise direction of the samples was carried on until fiberhe same time, which offer fibers with several newweb was totally hydroentangled on one side, and then thefeatures. Table 1 shows the tensile propertics of cardedconsolidation was continued to the opposite side.fiber webs before hydroentanglement.Two passes for each side were used so as to attain goodIn Table 1, it shows that the tensile strength in thehydroentanglement efficiency. Some of the processingmachine direction was higher than in crosswise direction,this can be due to anisotropic properties of textile materialsvariables were jet density (3 jets/cm)，nozzle orificediameter of 0.3 mm and web velocity of 0.72 m/min. Thecspecially for carded webs in which most of fibers aredistance between the fiber web and the jet plate on thealigned in machine direction. Secondly the data in Table 1manifold was changed according to the requirement, but inindicates that islands-in-the-sea fiber webs were strongerthis study the distance was fixed at 20 mm. Afterthan pie segmented fiber webs; probably this can be due tohigher packing density of islands in-the-sea fibers ( PET/consolidation the webs being hydroentangled were squeezedCOPET) in its carded web compared to tbat of carded piewithin perforated wires to remove excess water and thensegmented fiber webs. This means the openness in PA6/dried by air at room temperature.PET carded webs were higher which caused the web to be1. 4 Physical measurementsvery weak during deformation. From Table 1 it can beAfter hydroentanglement we evaluated the hydroentangledseen that the tensile strengths are much smaller than thenonwoven fabrics for tensile strength using Universal Materialtenacity of fibers. This result reflects the weakest behaviorTensile Tsting Machine (AGS -500ND). The tensile testingof carded webs, so during deformation the fibers slides toprovides much information such as breaking load, theeach other and moved apart without damage of fibersstrain at peak load, energy at peak load, and modulus of(fibers do not break) so the tensile strength at break wasfabrics etc. The test was performed on a tensile testingless than that of fibers. In Table 1, it indicates that for allmachine according to ASTM D 5035 - 95 (strip method)carded webs, the coefficient of variation for tensile[6]. The sample size was 50 mm (width) x 170 mm (length)strengthis in the range of 1. 35%- 19. 75%. Table 2and samples were cut at angles of 0' for crosswise directionshows tensile strength of carded fiber webs after(CD) and 90' for machine direction (MD). The gauge lengthhydroentanglement. In Table 2, it highlights thewas fixed at 100 mm and the tensile speed was 250 mm/ min ascofficient of variation of tensile strength forwell as the load cell of 50 N was used. Five samples in eachhydroentangled PA6/PET fabrics are in the range ofdirection were tested and the results for tensile strength and5.62%- 20.18% and PET/COPET fabrics in the range ofcoffcient of variations are represented with the averages4.31%- 19.50%. May be due to non-uniformity of fiberTable 1 Tensile strength ratio, tensile strength and strainat break of fiber web before hydroentanglementStrengthTensile strength at breakStrain at breakSampleratioWeightFiber types(g/m2)cuttingAverageCofficient ofCoefficient ofdirectionvalueMD/CDvariationvalue (%)(N/5 cm)500.14.5255.728.23.2.066PET/COPETCD0.04819. 75109. 6524. 98000.1324.81 .51.125.142.650oCI0.0510. 645109.4627.6MD0.0291.042PA6/PET0.028中国煤化工1oo0.057YHCNMHG81.5170.038.505.155co. 524ote; MD-Machine Direction, CD-Crosswise Direction416Jourmal of Donghua University (Eng. Ed.) Vol. 24, No.3 (2007)Table 2 Tensile strength at break of carded fiber webs ufter hydroetanglementPA6/ PET FabricsPET/COPET FabriesTensile strength at breakampleAverageCoefficientWeightPgJetvalueof variation(g/m')(bars)angle,NEC、dirction(N/5 cm)(%)MD4.24017.480.21917.546031. 09612.720.08411.283. 94618.880.1699.646(20*CD0.91417.580.05111.0833. 2017.070.31113.779.25 .13. 320. 14715.5432. 1815.99 .0. 28018. 1920"8. 57418.667.385. 53019.990. 32613.191000:D1. 59020.1819.509. 38812.69 .0.47515. 361002. 44815.7616.0939.239.190.8314.3110. 7617.0410.1941.935.621. 25016.08D11. 607.600.28115. 11Note: Pg- Water jet pressure, MD -Machine Direction, CD- -Crosswise Directiondistribution and unevenness thickness of fiber webs was the。1.4reason for higher coefficient of variation.2. 1 Effect of basis weight on tensile strength0.口60 g/mFigs. 3 and 4 show the influence of varying fiber webo 100 g/mjbasis weights on fabric tensile strength at break. Figs. 3 and 4; 0.日0.have indicated that with increase of basis weight from 60 to100 g/m2 , tensile strength in both MD and CD for all PA6/(a) Fabrics(PET/COPET)PET and PET/COPET fabrics were increased. As shown inFigs. 3 and 4, the interesing resuts show that for 60 g/mf仓官0.25E z0.15060 g/m]|图100g/mi 40首0.1: 300.0向60 g/mll图100g/mi0一-(b) Fabrics(PET/COPET)oFg4 The efet of basis weight on tensile strength of(a) Fabries(PA6/PET)PA6/COPETfabrics the tensile strength decrease happen at 3 burs and20' inpressure level of 3 bars. Further- more the decrease happen at口60 g/ml7 bars and 20" in when considering pressure level of 7 bars,| 日100g/mwhere 1, 2, 3 and 4 on horizontal axis reresent at 3 bars and, at7 burs and 20'，rospep中国煤化工fushing out of fibers(b) Fabrics(PA6/PET)forYHC N MH Gwhen the water jetsFig.3 The efet of basis weight on tnsile strengt ofinclination angle increased to 20， which caused thePA6/PET fabrisdeterioration of tensile strength.Joumal of Donghua University (Eng. Ed.) Vol. 24. No.3 (2007)4172.2 Effet of inclination angle un tensile strengthsegmented fabrics of low weight (60 g'mi ). from Fig.7 itFigs. 5 and 7 show the effect of inclination angle ofis indicated that as the ingle of inclination increiased in thewater jets on tensile strength of island in se;same pressure level, the fabric tensile strength wahydroentangled fabrics and pie segment hydroentangleddecreased, probably this may be due to the followingfabrics, where 1, 2, 3 and 4 on horizontal axis represent atreasons:0" with3 bars, at 20^ with 3 bars, at 0' with 7 bars, and atInclined wvater jets20' with 7 bars, respectively. Tensile strengths at break inVerical water jetsMD for all fubrics were significantly higher than those in|Fiber webCD, this is supported by the results in Figs. 5 and 7, andthis can be attributed due to better hydroentanglement ofL:/many fibers aligned on the machine direction. Furthermorethe reduction of tensile strength at break in CD may be alsodue to low jet density used in this study.Fig.6 Path distance of jets through fiber web日MDCD口MDOCD|(间) Fabrics(PA6/PET), 100g/mi(a) Fabrics (PA6/PET), 60 g/mi1.0.35z 0.回MD0.25后0.CD ]三0.品MO|0.4i 0.1西0.05(6) Fabrics(PA6/COPET). 100 g/m2(b) Fabrics (PA6/COPET), 60 g/mi'Fig.5 The efe of inclination angle on tensile strenghFig.7 The effect of inclination angle on tensile strengthFrom Fig. 5 it indicated that as the angle of inclinationof hydroentangled fabricsincreased from 0' to 20* , the tensile strength was increasedfor all fabric types of 100 g/m2 in weight in the sameWhen inclined water jets strikes the fiber webs, theypressure levels. The increase of tensile strength of thetend to flush out some of the fibers within the fiber webhydroentangled fabrics may be caused due to the followingand this effect becomes more significant in low weightsreasons: (a) We assume that when the constricted inclinedfiber webs due to their few fibers in cross section areas ofwater jets strikes the web support, the reflected water jctstheir fiber webs compared to heavy fiber webs. Since in thewill not have the same velocity, so the fibers are beingfiber webs of 60 g/m2 have few fibers in the cross sectionstroked with different jet velocities which cause thearea some of the fibers may be stroked and flushed awayincrease of turbulence efects within the webs compared toduring hydroentanglement process and disturbed thevertical water jets, this action increases hydroentanglementstructure uniformity with reduction of strength oefficiency as a result, the fabric tensile strength increased.entanglement points, so this would deteriorate the strength(b) The inclined water jets when strikes the fiber webs theyof the hydroentangled fabrics. Furthermore when thetraveled long distance (long path) within fiber web beforewater jets inclination angle increased to 20” the impactthey strikes the screen mesh compared to vertical water jetsforce and drag force decreased slightly. The resultantwhich their path are short (see Fig. 6 which shows patheffect with flushing actions and reduction of drag anddistance of water jets). The water jets in the long pathimpact forces on fibers deteriorate the fabric tensiletends to displace, twisting, rotating and knotting manytrengtto the ones treatedfibers on themselves compared to perpendicular verticalwith F中国煤化工water jets, therefore more bonding points can be formed asY片C N M H Gnce of vertical waterjets ofu ana L2 represents patn aIstance of inclined watera result fabric tensile strength increased.For the case of both islands in-the-sea and piejets of inclination angle (a= 20"). L2 is greater than L.418Joumal of Donghua University (Eng. Ed.) Vol. 24. No.3 (2007)2.3 Effect of jet pressure on tensile strengthThis hus goou agreement with previous theoryFigs. 8 and 9 indicate the effect of water jet pressurementioned befor . .nd in our graphs there were no turningon fabric tensile strength at break for both 60 g/m2 andpoints because of low pressures used. The tensile strength100 g/m2 of islands-in-the-sea ( PET/COPET) and piein MD for both fabrics was higher than in CD, this may besegmented (PA6/PET) fabrics, where 1, 2, 3 and 4 ondue to anisotropic nature of carded webs.horizontal axis represent at 3 bars with 0', at 7 bars withFigs. 8 and 9 indicate that the tensile strengths at break0", at 3 bars with 20"，at 7 bars with 20* , respectively.for pie segmented (PA6/PET) fabrics were higher thanthat of islands- in-the- sea (PET/COPET) fabrics probablythis is due to the fact that the pie segmented fibers (PA6/PET) bend and entangled easily due to their low flexural30-口MD1CD |rigidity compared to islands- in-the-sea fiber ( PET/COPET). This resulted increasing of entanglement pointswhich caused increase of tensile strength of PA6/PETfabrics than that of PET/COPET fabrics.(a) Fabrics(PA6/ PET), 100 g/mi3 Conclusion石MDThe conclusions from our investigations may beCD Jsummarized as follows:(1) As the water jet pressure increased the hydroentan-gled nonwoven fabrics tensile strength increses.(b) Fabries(PA6/COPET), 100 g/m2(2) As the water jets inclination angle increased fromFig.8 The effect of jet pressure on tensile0* to 20* in the same pressure level, the hydroentangledstrength of hydroentangled fabricsfabric tensile strength of 60 g/m2 fabrics decreases whilefor 100 g/ m2 fabrics increases.。40Based on the work of this paper, further research, is30still needed by considering different types of water jets20MDinclination angles with their effects on more fiber types for四CDobtaining more fundamental understanding of the effect ofwater jets inclination angle in hydroentanglement process.(a) Fabries (PA6/PET).60 g/m2Acknowledgements0.35T磊豆0.The authors would like to acknowledge the financial冠n0.25口MDsupport received from Tanzania Industrial Research and口CD j号20.15Development Organization ( TIRDO ) and ChinaScholarship Council (CSC).(6) Fabries (PA6/COPET), 60 g/mtReferencesig.9 The effect of jet pressure on tensile[1] Albin F Tutak. 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