| As the core part of China’s nonwovens,the spunbonded nonwovens have gradually exposed problems such as product variety simplification,product performance homogenization,and overcapacity as market regulation and technological innovation lag behind.The outbreak of the COVID-19 has further exacerbated these problems.The spunbonded nonwovens technology must be upgraded to move towards high-end industrial development.The bi-component composite spinning method can use different polymer raw materials to produce products with different properties,such as sheath-core,side-by-side and matrix fibrillar type fibers,through different composite forms and reinforcement methods.However,the bi-component spunbonded nonwovens on the market are mainly sheath-core and matrix fibrillar bi-component nonwovens,with fewer sideby-side products.In recent years,side-by-side bi-component nonwovens have gradually attracted the attention of enterprises and scholars,but the research direction is mainly focused on personal medical protection and filtration.Due to the different supramolecular structures of the bicomponents,the side-by-side bicomponent fibers shrink and curl due to the different degree of disorientation of the bi-components after heating.The prepared high crimp side-by-side filament nonwovens have the characteristics of light,fluffy and soft,and can be used as potential thermal insulation materials.Based on the crimp mechanism and influencing factors of side-by-side bicomponent fibers,this paper systematically explored the influence of spinning process and heat setting process on the crimp performance of side-by-side filament fibers,and explored the influence of through-air bonding process on the bulkiness,single compression,cyclic compression and thermal insulation performance of high crimp side-by-side filament nonwovens.Finally,the performance of PE/PET sheath-core staple nonwovens prepared by the same through-air bonding process was compared,The main work and contents are as follows:In this paper,high-density polyethylene(HDPE)and polypropylene(PP)were selected as raw materials,and the rheological properties of the polymer melt were systematically investigated by melt flow index.The spinning temperature was determined to be 230 ℃.By controlling the rotation speed of the metering pump,the side blowing fan and the suction fan,the side-by-side filament fibers with a composite ratio of 0.38-0.44 are obtained,which have excellent potential crimp potential.The optimum spinning process and heat setting process were determined by single factor experiment and orthogonal experiment.Metering pump speed is 240 rpm,side blowing and suction fan speed is 1000 rpm,the heat setting temperature is 110 ℃,and the heat setting time is 1 min.The effects of through-air temperature,through-air time and cooling rate on the properties of high crimp side-by-side filament nonwovens were investigated.The results show that with the increase of through-air temperature,the areal density of side-by-side filament nonwovens increases first and then decreases,the thickness,porosity and bulkiness increase,the compression work,compression recovery work and cyclic compression displacement shift increase first and then decrease,the compression rate increases,the compression recovery rate decreases,the air permeability increases,and the clo value decreases first and then increases.With the increase of through-air time,the areal density and thickness of side-by-side filament nonwovens increase,the porosity and bulkiness decrease,the compression work and compression recovery work decrease,the cyclic compression displacement offset rate increases,the compression rate,compression recovery rate and air permeability decrease,and the clo value first rises and then decreases.With the increase of cooling rate,the areal density of side-by-side filament nonwovens has no obvious change,the thickness,porosity and bulkiness decrease,the compression work,compression recovery work and cyclic compression displacement shift increase first and then decrease,the compression rate and compression recovery rate both decrease first and then increase,the air permeability has no obvious change,and the clo value decreases.The properties of PE/PP(EP)side-by-side filament nonwovens and PE/PET(ET)sheath-core staple fiber nonwovens were compared under the same through-air bonding process.The results showed that the compression rate,compression recovery rate and water washing resistance of the two nonwovens met the requirements of the first-class of spray-bonded cotton for wadding;The displacement offset ratio of 50 cycles of compression is lower than 1.5%,and the compression durability is good.The air permeability of EP side-by-side filament nonwovens is lower than that of ET sheath core staple fiber nonwovens.The thickness,porosity,bulkiness,clo value and water washing resistance are significantly improved. |
PDF Full Text Request