【作者】 夏治刚；

【导师】 徐卫林；

【作者基本信息】 东华大学 ， 纺织材料与纺织品设计， 2012， 博士

【摘要】 环锭纺占全世界纺纱总量的80%以上,中国环锭细纱机就有近1亿锭。环锭纺纱最大问题之一是毛羽问题。毛羽过多会导致纱线织造时摩擦力过大、开口不清,织物易起毛起球,织物染色后色差大等问题。针对降低环锭纺纱毛羽,许多新型纺纱方法应运而生,主要有负压集聚纺、机械集聚纺、赛络纺和分束纺等。这些新型纺纱方法共同点是通过机械外力加强纤维控制,提高纺纱质量,且各自存在不足。其中赛络纺和分束纺成本较低,但产品适用范围有限；负压集聚纺不仅安装运行成本高,且对高刚度、高弹性卷曲的纤维集聚纺纱效果差。与上述新型环锭纺纱方法不同,本文以湿热对常见纤维素纤维拉伸力学性能影响的研究为基础,建立了通过在线降低纤维刚度以降低纱线毛羽的“新型柔顺光洁纺纱”方法,研制出安装运行成本低的较成熟柔顺光洁纺纱装置,并成功地应用于棉、苎麻和粘胶纤维的柔洁纱的纺纱实践。采用变温红外光谱(TD-FTIR)、热失重-差示扫描量热分析-质谱(TG-DSC-QMS)联合分析技术,对常见纤维素纤维的热稳定性能进行研究。TD-FTIR分析结果表明棉和苎麻纤维在25-210℃温度环境下,短时间暴露未出现严重降解或分解现象,且随温度增加,棉和苎麻内强结合水逐渐散失；温度低于150℃时,粘胶纤维内部大分子结构未发生变化,且随温度增加,粘胶内部强结合水逐渐散失。TG分析结果表明：棉在30-200℃范围内失重对应强结合水散失,250-600℃范围内的失重对应纤维素热降解失重；苎麻在30-250℃范围内的失重对应强结合水散失,280-600℃范围内的失重对应苎麻纤维热降解；粘胶在30-220℃范围内失重对应粘胶样品强结合水散失,在240-600℃范围内的失重对应粘胶样品热降解。棉DSC曲线上有两个吸热峰,65.0℃吸热峰对应棉内部强结合水散失,371.2℃位置吸热峰对应棉热降解；苎麻DSC曲线上第1吸热峰对应强结合水散失,第2吸热峰对应半纤维素、木质素、果胶等非纤维素物质降解和纤维素软化,第3吸收峰对应纤维素热降解,第4吸收峰对应未彻底降解物质发生二次降解；粘胶DSC曲线上63℃吸热峰对应纤维内部强结合水散失。QMS分析结果表明：棉高温降解释放出NO、CO2、CH4、C3H4等小分子物质；苎麻热降解释放出O2、NO、C4H7、CH4、C4H3、C3H6、C3H3等小分子物质。采用自制加热装置对常见纤维素纤维的湿热静态拉伸力学性能进行研究。棉纤维热拉伸实验结果表明随加热温度升高,棉纤维初始模量先下降,在90℃处初始模量有所上升,然后又下降；加热温度越高,棉纤维断裂强力和断裂伸长越小。苎麻纤维热拉伸实验结果表明加热温度升高,苎麻纤维热拉伸初始模量逐渐降低,纤维断裂强力明显下降,断裂伸长降低。苎麻湿拉伸初始模量降低；这是因为浸湿后的纤维素大分子间氢键束缚力解除,分子链更易运动。苎麻湿拉伸比常态拉伸断裂强度增加,这是因为湿态苎麻拉伸时内部原本剪切、弯曲受力的分子链得以伸直,使得更多伸直分子主链承受拉伸；其次,水分子进入苎麻纤维内部,有助于纤维大分子受力拉伸时发生取向调节,消除应力集中点。与常态拉伸相比,苎麻纤维热湿拉伸初始模量、断裂强力明显下降,断裂伸长有所升高。采用DMA-242型动态热机械分析仪对常见纤维素纤维的动态热力学(DMTA)’性能进行表征分析。结果表明：天然棉单纤的E’-T曲线、tanδ-T曲线呈现出较大曲线波动,苎麻对应的E’-T曲线、tanδ-T曲线波动较小,这是因为棉纤维具有天然转曲结构,而苎麻纤维较平直。苎麻湿态单纤维起始储能模量比干态单纤起始储能模量低,这说明苎麻单纤维吸湿后,纤维内部大分子链间作用力减弱,弹性和刚度下降。棉和苎麻束纤维DMA表征结果一致呈现出：含4根单纤的纤维束(简称束4)储能模量低于相同条件下含2根单纤的纤维束(简称束2)拉伸储能模量。这是因为相同单位内捻回数相等,束4比束2捻系数大,内层纤维受到外层纤维侧向压力增加,纤维间摩擦增大,受力后弹性回复阻力变大,回复能力下降；另外纤维根数越多,纤维之间接触面积越大,弹性回复时损耗模量较多,储能模量降低。首次以湿热对纤维素纤维的静态、动态拉伸性能研究为基础,创造性地建立了柔顺光洁纺纱方法：对纺纱加捻三角区纤维进行热湿柔化,降低纤维刚度,使得纤维更易弯曲、加捻；同时,柔顺处理工作面与纺纱三角区纤维须条进行接触,形成许多纤维握持点,增加对外露纤维头端的握持,并与加捻转动力、须条牵引力协同作用,将外露纤维端有效地转移进入到纱线体内,降低纱线表面毛羽,改善光洁度。对柔顺光洁纺纱方法进行理论分析得出：外露纤维头端越长、纤维刚度在线降低幅度越大,纱线毛羽就越容易通过加捻、扭转进入纱线主体而消除。另外柔顺光洁纺纱过程中,纱条与柔顺光洁处理面接触长度越长,毛羽降低率越高；纺纱速度越低,纱条与柔顺光洁处理面接触时间越久,纱线毛羽降低率越高；柔顺光洁纺纱装置越靠近纺纱三角区,经过柔顺处理面的纱条增加捻回数越多,纱线毛羽降低率越高。当柔洁纺纱过程降低毛羽在纱体上形成局部集聚现象时,降低纱线毛羽会导致纱线主体条干恶化；当柔洁纺纱过程降低毛羽在纱体上以较长螺旋路径进入或紧紧包缠在纱体主干时,就能避免降低纱线毛羽导致丝线主体条干恶化。成功地研制出较成熟柔洁纺纱装置,并对纯棉纱、纯苎麻纱、纯粘胶短纤纱进行柔顺光洁纺纱生产实践。实践结果显示：柔洁棉纱与对应的普通环锭纺原纱相比,纱线毛羽大幅降低,特别是管纱3mm毛羽降低率在60%以上,纱线条干指标不恶化、纱线强伸性能有所改善；柔洁苎麻纱与普通原纱相比,毛羽大幅降低,其中3mm毛羽降低率高达70.45%；与对应的原纱相比,粘胶柔洁纱毛羽大幅降低,其中3mm毛羽降低率高达93.55%。研究了关键柔洁纺纱工艺对柔洁纺纱效果的影响。研究结果表明：柔洁纺纱装置越靠近环锭纺纱三角区,纱线毛羽降低率越高,纱线强力较高,但由于固定式装置与越脆弱的成纱段接触,越易导致脆弱成纱段受纺纱张力波动而出现牵伸不匀,纱线条干有所恶化；纱条以与柔顺工作面切入线呈右斜(45-60)°夹角的路线进入柔顺工作面时,柔洁纺纱毛羽降低率较高,成纱条干较好,成纱强力较高；与平板状、凹板状柔顺工作面相比,凸板状柔顺工作面所纺柔洁纱毛羽更少；摩擦系数较大的柔顺工作面所纺柔洁纱毛羽较少,成纱条干较差；柔顺工作面与纱条接触紧度越大,柔顺工作面对纱条表面毛羽的握持力越强,表面所纺纱线毛羽较少,但接触过紧易出现较大捻陷效应而阻止捻度上传到纺纱三角区,因此较高接触紧度条件下所纺纱线条干CV较高；其它纺纱工艺条件相同,所纺纱支越细,未成纱区间越长,柔洁纺纱装置接触到的未成纱段长度越长,柔顺光洁纺纱装置降低纱线毛羽的程度和牢度越高。形成了环锭柔顺光洁捻线方法：在普通环锭捻线三角区,施加热湿接触面,对捻线三角区纱线进行热湿处理,使得纱线表面纤维柔性大幅度提高,柔化后的纱线表面毛羽在捻度变化产生的扭转力和接触热湿工作面所产生的握持力共同作用下,更容易捻入到纱体内,并通过纱线汇合后相互抱缠,进一步牢固封锁在股线结构体中。对柔顺光洁捻线方法进行理论分析研究得出：环锭光洁捻线降低毛羽的同时,柔洁股线条干有所改善,主要是因为单纱从前罗拉钳口输出且未达到捻合汇聚前,受到热湿牵伸作用,单纱毛羽降低在纱体上不形成局部集聚现象。采用自制柔顺光洁捻线装置对80英支纯棉单纱进行柔洁环锭捻线实践。实践结果表明：柔顺光洁捻线装置能大幅降低传统环锭捻线的股线毛羽,改善股线条干和强力。更多还原

【Abstract】 More than80percent of spun yams are produced by ring frame in the world; there are almost100million ring spindles in Chinese textile industry. Hairiness is one of the most important problems for yarn manufature because excessive hairiness will cause sever weaving abrasion and shed clinging for yarn weaving, pilling and uneven dyeing problems for resultant fabric. Therefore many novel ring spinnig methods are applied to reduce yarn hairiness such as pneumatic condensed spinning, mechnical condensed spinning, sirospinning, solospinning. These novel spinning methods can enhance fiber-strand control via various conventional external mechnical actions; however there still exists inadequacy for some of them. For example, sirospinning and solospinning have a limited application and are not suitable for high count staple yarn production; pneumatic condensed spinning (PCP) has been widely recognized as the most expensive method due to its high intallation and operation costs. Furthermore, PCP contributes very little to the improvement of spun yarn hairiness during the ring spinning of high rigidity or hi-crimp staple fibers. Different from aforementioned methods, this paper established soft and smooth ring yarn production theory on a basis of mechanism of moisture and temperature influence on cellulose textile fibers’ tensile properties. Soft and Smooth Ring Spinning (denoted as SSRS) devices were also well developed to conduct a successful production of Cotton, Ramie and Rayon smooth yarns.Thermal properties of cellulose fibers were characterized by using TD-FTIR and TG-DSC-QMS. TD-FTIR analysis results indicated that strong-bond-water of fiber evaporated gradually without obvious thermal degradation for cotton and ramie when they were heated under a rising temperature from25℃to210℃; Rayon cellulose fiber suffered a strong-bond-water loss without chemical structure change when it was exposed at a temperature lower than150℃. TG analysis results indicated that cotton mass loss at30-200℃corresponded to strong-bond-water evaporation, loss at250-600℃corresponding to thermal degradation; ramie mass loss at30-250℃corresponded to strong-bond-water evaporation, loss at280-600℃corresponding to thermal degradation; Rayon mass loss at30-220℃corresponded to strong-bond-water evaporation, loss at240-600℃corresponding to thermal degradation. According to cotton DSC curve, the fastest water losss occurred at65℃while the fastest mass loss due to thermal degradation ocured at371.2℃. Four endothermic peaks in ramie DSC curve could be explained as follows:peak1corresponded to strong-bond-water evaporation; peak2was ascribed to non-cellulose material degradation and cellulose softening; peak3corresponded to cellulose degradation; peak4was ascribed to secondary degradation. Rayon DSC curve showed that the fastest strong-bond-water evaporation occurred at63℃. QMS results showed that cotton fiber released NO, CO2, CH4, and C3H4during high-temperature decomposition, ramie fiber releasing O2, NO, C4H7, CH4, C4H3, C3H6and C3H3.Self-built heating devices were applied to study effect of temperature on cellulose fiber static tensile properties. Results showed that cotton fiber initial modulus decreased first, then increased slightly at90℃, afterwards decreased obviously as the heating temperature rised. However cotton fiber break force and elongation decreased gradually as the temperature increased. Ramie fiber initial modulus, break force and elongation decreased abviously as the heating temperature increased. Wetting treatment could reduce ramie fiber initial modulus, which was because water could weaken hydrogen bonding between cellulose macromolecules. Ramie fiber tenacity increased after wetting treatment; this could be ascribed to the increasing of inner macromolecules’parallelisms and improving of fiber inner structure to decrease weak regions during the wetting drawing process. Moreover, ramie fiber showed a large decrease of initial modulus and break-force and an increase of break-elongation for drawing in hot vapor condition.DMA-242type dynamic mechanical thermal analysis instrument was used to test cellulose fibers’dynamical tensile properties. Results indicated that severe vibrations exsisted for single cotton fiber E’-T and tanδ-T curves; while single ramie fiber E’T and tanδ-T curves were much smoother. This resulted from that cotton fiber had natural convolution while ramie fiber was relatively straight. At low temperature, wet ramie storage modulus was lower than that of dry one, which indicated that wetting could reduce the rigidity of ramie fiber as hydrogen bonding weakened between cellulose macromolecules. DMA results of cotton and ramie fiber bundles were consistent in that the bundle of4fibers had a lower storage modulus than that of2fibers. This could be explained as follows:higher twist factor in the bundle of4fibers would inhibit more elastic recovery by increasing the friction between fibers; furthermore, more fibers in the bundle meant larger contact surface to result in higher loss modulus and lower storage modulus.On the basis of the mechanism of moisture and temperature influence on cellulose textile fibers’ tensile properties, Soft and Smooth Ring Spinning (denoted as SSRS) method was firstly established as follows:a hot surface was applied to contact and soften fibers in the spinning trangle during the ring spinning process; softened yarn hairs could be easily re-spun into yarn stem under a synergitic action of contact gripping force and twisting tortional force; then a smooth yam was produced as its surface hairs were largely reduced. Theoretical analysis of SSRS indicated that the longer the hair was, the easier the hair could re-spun into yam stem; a more sever softening of fibers meant a larger yam hairiness reduction; a longer yam contacting hot surface resulted in a larger hairiness reduction; a lower spinning speed resulted in a larger hairiness reduction; a nearer of the contact surface to the front nip line caused a larger hairiness decrease. Fiber accumulation in a short distance of yarn stem during hairiness reduction should be suppressed to avoid deteriorated yarn evenness.Efficient apparatus was successfully developed for soft and smooth ring spinning of cotton, ramie and rayon fibers respectively. Results showed that SSRS apparatus could eliminate60%3mm hairs of conventional cotton yarns, and cotton smooth yarn (denoted as "cotton Sm") produced by SSRS had less hairiness, higher strength and non-deteriorated unevenness compared with the corresponding conventional ring cotton yarn. Ramie Sm with a less hairiness was also successfully manufactured by SSRS apparatus; in specialty,70.45%3mm hairs were reduced during ramie SSRS.60%3mm hairs were eliminated by SSRS apparatus during the rayon spinning; thus, rayon Sm was much smoother than the conventional rayon yarn.The influence of key SSRS parameters on spun yarn properties was also investigated. Results showed that the nearer of SSRS apparatus to the spinning triangle resulted in higher hairiness reduction ratio and higher strength improvement of yarn; however the yarn unevenness showed a very slight deterioration as the fixed SSRS apparatus was apt to cause unexpected drawing due to dynamical spinning tension when it contacting a more loosened yarn section. Fiber mass concertration in a short distance to deteriorate unevenness could be avoid by delivering yarn to SSRS apparatus surface in a right angle of (45-60)°with the entrance edage of SSRS apparatus; Under situation, much better hairiness and tensile properties of Sm yarn were still secured. Among such three types of contact surfaces as plane, concave and micro-convex, the micro-convex hot contact surface produced Sm yarn with the least hairiness. The hot contact surface with a higher friction would reduce more hairs, yet lead to a worse unevenness of yarn during the SSRS process. A tighter contacting of spinning strand with the hot surface meant a higher friction and more twist block; therefore the corresponding spun Sm yarn had less hairiness and worse unevenness. Under the same spinning paramenters, the thiner roving used to produce Sm yarn, the longer the Sm yarn information zone would be; thus SSRS apparatus could reduce more hairs by nesting the fiber ends in yarn stem more tightly during the spinning of a thinner Sm yarn. Soft and Smooth Ring Plying (denoted as SSRP) method was firstly introduced as follows:a hot and wetting surface was applied to contact and soften single yarns in the spinning trangle during the ring plying process; softened hairs of single yarns could be easily re-spun into yarn stem under a synergitic action of contact gripping force and un-twisting tortional force; then the singles were combined to twist with each other to further trap reduced hairs into plied yarn structure. Theoretical analysis of wet SSRP indicated that wet SSRP could reduce hairiness and improve unevenness of plied-yarn as wet SSRP would avoid fiber mass concertration to deteriorate yarn unevenness when reducing yarn hairs during the hot-wetting plying. Furthermore, self-built SSRP apparatus was employed to the plying of two Ne80s single cotton yarns for validation of the SSRP theoretical analysis. Results indicated that smooth plied cotton yarn produced by self-built SSRP apparatus processed much fewer hairs, higher tenacity and better unevenness than the convetional ring plied cotton yarn.更多还原