高速切向射流旋转场中纱线增强机制与结构成形理论研究

Jet vortex spinning adopts tangential air-jet rotating field to twist the open-end trailing fibers into a yarn. The strength of vortex spun yarn is 70%-85% of ring spun yarn and its yarn count spun is limited. It was rarely applied to the weaving area. These facts limit the product development and application of vortex spun yarns. New key components and parts are introduced in this project, and the strength of vortex spun yarn is improved by reconstructing yarn structure. The hollow spindle with spiral guide groovy is introduced into yarn twisting part, which can enforce the phenomenon of fiber self-twist and migration for vortex spun yarn in twisting chamber, resulting in the increase of yarn strength. The airflow low in twisting chamber consisted of hollow spindle with spiral guide groovy is analyzed by adopting the theory of three-dimensional fluid dynamics, which can reveal the fiber motion feature and formation mechanism of yarn structure. The influence of spiral guide groovy number and shape structure of hollow spindle on yarn structure and property is studied. The spiral fiber passageway with central pore and no guiding needle is introduced in order to guide filament fiber entering yarn core. The filament fiber located in the yarn core can improve the strength of vortex spun yarn. The influence of yarn formation process and filament property on yarn structure and property is investigated. The heating equipment, such as heating tension roller, is introduced to heat low melting point fibers. Based on the mechanism of heat bonding, the strength of vortex spun yarn is increased by adding low melting point fibers into the yarn. The influence of blend ratio and distribution pattern of low melting point fibers in the vortex spun yarn as well as yarn formation process on yarn structure and property is discussed. These research achievements can establish the theoretical foundation for the design and development of differential high vortex spun yarns.

喷气涡流纺采用切向射流旋转场对自由尾端纤维加捻而成纱，其纱线强力约为环锭纱的70%-85%，可纺纱支受限，很少在机织领域中应用，限制了产品开发与应用。项目拟引入新型关键成纱元器件，从纱线结构重构出发实现喷气涡流纱强力的提高。引入具有螺旋导引槽的空心锭子，利用加捻腔纤维自捻与内外转移提高成纱强力，运用三维流体动力学理论，分析由螺旋导引槽空心锭子构成的加捻腔气流流动规律，揭示纤维运动特征与纱线结构成形机理，研究空心锭子表面螺旋导引槽数、形状结构等对纱线结构形成与性能的影响；引入无导引针的带中孔螺旋纤维通道，基于长丝增强原理提高成纱强力，探索成纱工艺与长丝特性对纱线结构与性能的影响；引入加热张力罗拉等加热装置，基于热粘合机制，利用低熔点纤维加入来提高成纱强力，探索低熔点纤维添加量、低熔点纤维分布形态与成纱工艺对纱线成形过程与结构性能的影响。课题研究成果为差别化高强喷气涡流纱产品开发提供理论依据。

喷气涡流纺采用切向射流旋转场对自由尾端纤维加捻而成纱，但自由尾端纤维是以滑动方式绕空心锭子入口旋转包缠纱芯，纤维在纱线截面内内外转移现象较少，是导致纱线强力较低的重要原因之一；再者喷气涡流纺成纱加捻腔的气流从喷孔喷射后流速自上而下呈衰减趋势下行，会引起对倒伏的自由尾端纤维加捻不均匀，影响成纱条干均匀性，导致纱线强力不高。. 项目从如何提高成纱强力着手，对空心锭子开展新型结构设计，引入具有螺旋导引槽的空心锭子，利用加捻腔纤维自捻与内外转移提高成纱强力，运用三维流体动力学理论，分析由螺旋导引槽空心锭子构建的加捻腔气流流动规律，揭示纤维运动特征与纱线结构成形机理，研究空心锭子表面螺旋导引槽数、形状结构等对纱线结构形成与性能的影响；引入无导引针的带中孔螺旋纤维通道，研究基于长丝增强原理的高强喷气涡流纺纱线开发；基于热粘合机制，利用低熔点纤维加入来提高成纱强力，探索热处理方式、热处理工艺等对纱线成形过程与结构性能的影响，并分析热黏合增强喷气涡流纱机制。研究结果表明：对空心锭子上部表面刻槽处理，可以增加自由尾端纤维与空心锭子间的摩擦，实现自由尾端纤维在加捻过程中产生自捻现象。进一步通过对空心锭子上部外表面的螺旋导引槽设计，可引导喷射气流向加捻腔下部运动，增强加捻腔气流的流动均匀性，使自由尾端纤维产生自捻与内外转移效应，实现纱线强力提高。基于长丝增强喷气涡流纺纱线强力原理，成功开发了基于竹节特征的喷气涡流纺包芯纱。引入低熔点纤维，通过对热黏合方式选择、热黏合工艺控制与优化，促使喷气涡流纺纱中低熔点纤维受热产生挤压变形、点状与团块状黏结，从而实现对喷气涡流纺纱线强力的增加。利用对加捻腔中纤维的受力分析与纱线几何结构模型的构建可用来解释喷气涡流纺纱线强力增强机制，并有效实现喷气涡流纺纱线强伸性能预测。基于喷气涡流纺成纱过程控制关键技术研究，并与色纺企业开展合作，实现了高强、风格可控调节的高品质喷气涡流色纺纱开发。