基本纺织培训资料(Vicky1)

纺 织 培训材料 纤维 Fiber 纤维(What is a fiber?) 是一种细而长的物质，直径从几微米到十几微米，长度则从几毫米几十毫米甚至上千米，长径比很大。 纺织纤维 长度达到数十毫米以上具有一定的强度、一定的可挠曲性和一定的服用性能，可以生产纺织制品的纤维。

纤维的分类 classification

Man-made fibers 化学纤维(man-made fibers)：是指用天然的或合成的高聚物为原料，经过化学和机械方法加工制造出来的纤维。 再生纤维：以天然聚合物为原料，经过化学和机械方法制成的，化学组成与原高聚物基本相同的化学纤维。 如粘胶纤维(Vicose Rayon) 、醋酸纤维(Cellulose acetate) 、铜氨纤维（Cuprammonium fibers）Lyocell纤维、Tencel纤维、Modal纤维等。 合成纤维：以石油、煤、天然气及一些农副产品等低分子作为原料制成的单体后，经人工合成获得的聚合物纺制成的化学纤维。如涤纶(polyester)、锦纶6,66(nylon)、腈纶(Acrylic) 、丙纶Polyethylene 、氨纶Spandex (polyurethane), 氯纶Polyvinyl chloride 第二章 纤维及基本指标 Polymers Chemistry ◦ Backbones: -C-C-, -C-O-C-, -C-N-C- ◦ Configuration ◦ Side groups: -H, -CH3, -OH, CONH, -CN

Polymers Orientation and Crystallinity ◦ Highly oriented: large proportion of polymer chains are aligned with the fiber axis ◦ Crystalline regions: adjacent polymers are packed with spatial order ◦ Amorphous regions: no spatial order Orientation and Crystallinity Manufactured fiber formation ◦ Fiber spinning: extruding polymer melts or solution through a spinneret with up to thousands of holes 天然纤维长度（mm）范围 棉纤维： 25-45 亚麻单纤维：15-20 亚麻工艺纤维：500-750 化学纤维——人工制造，可根据需要而定。 长丝：可无限长； 短纤维：等长或不等长。 纤维的细度 细度：指纤维的粗细程度（沿长度方向）。 间接指标 利用纤维长度与重量的关系间接地来表示纤维的细度。 测量方便 Linear density Direct: length based: continuous fibers and yarns (Mass/unit length) ◦ denier ( den, Nd ): grams/9000m

◦ tex ( tex, Nt ): grams/1000m

◦ decitex ( dtex, Ndt ): grams/10,000m

间接细度指标间的换算关系： Ntex  Nm = 1000 Nden  Nm = 9000 Nden = 9 Ntex

纤维的机械性质 第一节 单纤维的拉伸性质 一、表示纤维拉伸性能的指标 指标有：断裂强力；断裂强度；断裂伸 长率 1. 断裂强力（绝对强力） 定义：纤维能够承受的最大拉伸外力。 单位：牛顿（N）；厘牛（cN)；克力（gf)。 对不同粗细的纤维，强力没有可比性。 2. 断裂强度（比强度） 定义：每特（或每旦）纤维所能承受的最大拉力。 单位：N/tex（cN/dtex）；N/den（cN/den)； gf/dtex。 其计算式为： Ptex=P/Ntex Pden=P/Nden 3.断裂伸长率 ε 定义：纤维拉伸至断裂时的伸长率称为断裂伸长率。 它表示纤维承受拉伸变形的能力。 其计算公式为： ε =（L-Lo）/ Lo 式中： Lo——纤维加预张力伸直后的长度（mm）； L ——纤维断裂时的长度（mm）； 第二章 常见纤维介绍 cotton 棉 Polymer system ◦ Linear cellulose ◦ Functional side group: -OH Properties Mechanical Properties ◦ Tenacity and initial modulus: medium ◦ Elongation at break: low: spiral fibrils: makes it relatively brittle ◦ Elastic recovery: low, only 75% at 2% extension: due to H-bond Properties Comfort ◦ Fiber ends and convolutions: comfortable to touch ◦ Hydrophilic: max water absorption: 25-27% regain due to -OH group and fibrils ◦ Upon water absorption, fibers become softer and collapses on to skin, dries slowly ◦ When it is dry: comfortable because of water absorption, water vapor transfer and no static charge ◦ Water resistant fabric possible: swelling of fibers in water: no liquid water penetration Other properties ◦ acids cause degradation of cotton or cellulose: acid free paper for long lasting items ◦ not affected by most of organic solvents ◦ damaged by fungi and bacteria ◦ prolonged exposure to sunlight: yellow ◦ heat resistant ◦ low luster ◦ high cover power

Rayon 粘胶 Definition: manufactured fibers composed of 100% regenerated cellulose, as well as manufactured fibers of regenerated cellulose in which substituents have replaced not more than 15% of the hydrogens of the -OH groups. Properties Mechanical ◦ Medium tenacity and elongation ◦ Low initial modulus ◦ Low elastic recovery ◦ Low bending rigidity ◦ Tenacity and modulus drops drastically upon water absorption: -50%. Elongation to failure +20%. Properties Comfort ◦ Hydrophilic and high moisture regain: 13% at 70% RH: more absorbent than cotton due to more amorphous region. High heat of wetting ◦ High cross-sectional swelling ◦ Irregular surface next to skin: comfortable ◦ No static charge build up Structure Smooth, even diameter ◦ diameter generally 12-25 mm ◦ white or off-white colors Intermolecular forces: ◦ dipole-dipole between benzene rings Linear polymer: DP 115-140 ◦ Crystallinity: depends on processing ◦ Orientation: very well oriented PET 涤纶 High tenacity due to high orientation High failure elongation Elastic recovery ◦ High with low stress: 97% at 2% strain. ◦ Low with high stress because dipole-dipole bonding is not strong enough to hold, leading to intermolecular slippage Low compressional resilience: not good for carpet fiber Properties Very low moisture regain Low level of wicking due to hydrophobic surface High electrical resistivity: static charge likely at low humidity Medium specific gravity Pilling High dimensional stability High Tm = 265ºC for PET Resistant to acids, potentially degrades in concentrated alkalies No UV degradation Flammable with black smoke Melt drip Best thermal resistance among all general use synthetics Modification  High tenacity for tire cord (higher DP and crystallinity)  Wicking  Sheath-core: polyester core, low melt polymer sheath  Du Pont Coolmax: 20% more surface area and maybe hydrophilic treated for wicking  Dupont Thermax: hollow fibers: excellent thermal insulation and 20% weight reduction