Study On The Mechanism, Structure And Properties Of Rotor-Spun Composite Yarns With Filament And Staple Fibers

In comparison with normal staple fiber yarns,the composite yarns consisting of staple fibers and filaments have shorter working procedure and higher output rates.They have special morphology and properties,and may be applicable to different kinds of fabrics.In this research, filament yarns and staple fibers are combined on a modified rotor spinning frame,and the composite yarns possess the characteristics of both filament yarns and staple fiber yarns.This new spinning technique not only keeps the advantages of rotor spinning,such as high speed,high output rates,short flow,reduced production cost,improved yarn evenness,but improves the yarn breaking strength radically,and different kinds of rotor-spun composite yarns can be produced by varying the spinning technique.This paper includes four parts.Firstly,Rotor-spun composite yarns and Sirofil are produced, and their performances are tested and compared,and their structures are analyzed.Secondly,a quasistatic model is established to determine the convergent points of the fiber strand and the filament during the spinning process under different spinning parameters.Thirdly,a linear dynamic model is established to determine the section area about the position of convergent point.Finally,a nonlinear model is established to determine the section area about the position of convergent point,and the resonance of the convergent point is discussed.Compared with sirofil,rotor-spun has high output,low quest for raw material,and reduced production cost.Rotor-spun composite yarns of cotton/terylene are produced on modified rotor spun machine.Sirofil yarns of cotton/terylene are produced on modified ring spun machine.The results show that the morphology of rotor-spun composite yarn is clearer and tighter than that of sirofil.The abrasion resistance of rotor-spun composite yarn is higher than that of sirofil.The force of pulling fibers from rotor-spun composite yarn is higher than sirofil.Sirofil is easier to get hairiness and pilling.The hairiness of rotor-spun composite yarn is much less than sirofil. The breaking strength of rotor-spun composite yarn is decreased but the evenness of strength is improved.The evenness of rotor-spun composite yarn is worse.We conclude that compared with sirofil,rotor-spun composite yarn have a smoother surface,less hairiness,higher abrasion resistance,less strength and worse evenness.Rotor-spun composite yarn of cotton/spandex is produced on modified rotor spun machine. Sirofil yarn of cotton/spandex is produced on modified ring spun machine.The results show that the morphology of rotor-spun composite yarn is clearer and tighter than that of sirofil.Sirofil is easier to get hairiness and pilling.The hairiness of rotor-spun composite yarn is much less than sirofil.Compared with sirofil,the breaking strength and the evenness of rotor-spun composite yarn are decreased.We conclude that compared with sirofil,rotor-spun composite yarn has a smoother surface,less hairiness,less strength with improved evenness and worse yarn evenness.The characteristic of the composite yarn depends mainly upon how and where the strands of fiber and the filament arc combined and mixed,so the convergent point of the filament and the strands of fiber are of crucial importance.We assume the system is in a stable condition.The governing equations for the system are got under the basic laws in mechanics,including force balance and mass conservation dealing with a seemingly complex dynamic industrial process of critical impotence in the textile industry—especially for the specialists in design and manufacturing—for the first time.Different spinning samples are tested by the model(rotor diameter:19mm,21mm,25mm;rotor speed:60000r/min,75000r/min,120000r/min; filament over feed ratio:0.91-1.18:filament fineness:40D,70D:composite yam fineness: 29.2tex,36.4tex,58tex).We conclude that the centrifugal forces acting on three components can't shift the convergent point much,and the speeds of the three components can change the convergent point,which affects ultimately the values of OFR and the tension.Due to some perturbations,the convergent point moves to an instantaneous new position.To study about the perturbations of the convergent point we set a linear model and a nonlinear model for rotor-spun composite yarn spinning process dealing with a seemingly complex dynamic industrial process of critical importance in the textile industry—especially for the specialists in design and manufacturing—for the first time..The linear theoretical model and the nonlinear model can be applied directly to the spinning process investigation.The models are able to simulate the phase diagram and the trajectories of the convergent point easily for different spinning parameters.By solving the linear model and the nonlinear model under different spinning parameters,phase diagrams of the ellipse demonstrate that the systems are stable,that is to say,the speed and the displacement both are in a certain scope for cosine or sine wing with time.We discover that as the filament over feed ratio increase, the vibration tends toward more stable.As the rotor cup becomes bigger,the vibration tends better.As the speed of the rotor cup becomes higher,the vibration becomes worse.As the filament denier becomes smaller,the vibration becomes worse.And as the composite yarn tex become middle,the vibration becomes better.To produce better composite yarns the parameters should be matched with each other.And we also discuss the possibility of the convergent point's resonance.