东华大染整原理（双语）课件Chapter 7 Thermosetting

Chapter7 Thermosetting(HeatSetting)Lecturer:Prof.Dr.Yankelu7.1IntroductionThedimensionalstability,dyeability,andotherpropertiesofthermoplasticfibersareaffectedbyrepeatedheatingandcooling.Themainpurposesofheatsettingareasfollows:Tostabilizethematerialtoshrinkage,distortion,andcreasing,Toimprovethedyeabilityoffabrics.定型三大内容：棉的丝光合纤热定型树脂整理合成纤维在纺丝成型中热处理时间较短，存在内应力；在织造过程中纤维、纱线受力也存在内应力。因此，合纤织物遇热易发生皱缩，织物幅面失去平整，印花花纹改变，成衣尺寸失去稳定性。定型的目的：消除织物上已有的皱痕和提高织物的热稳定性（主要指高温条件下的不收缩性）和不易产生难以去除的折痕。fiberdemandedyarnavailablemodalitywarestable7.2GeneralSituationofProcessingHeatsettingcanbedonewitheitherdryorsteam.Polyesterisusuallyheatsetdrywhilenylonmaybeheatseteitherdryorwithsteam.Continuousheatsettingofflatfabricsisusuallydonewithdryheatbyimpinginghotaironthefabricinatenterframe.Steamheatsettingisoftendoneinanautoclaveormaybedoneusingcontinuoussteamingequipment.7.2.1Drysettingmachineandprocess7.2.1.1DrysettingmachineseealsoAbb.7.290,p.184Pig.7-1,andMontex.7.2.1.2Processwidth:2-3cmbiggerthanfinishedsizeoverfeed:

30%(Clothfeedingdevice)Temperatureandtime:seealsoP.453Tab.31.doffing(cropping):<50oC(coldair;coolingcylinder)7.2.2WetsettingSaturatedsteamThepresenceofwaterapparentlypromotesmolecularchainrearrangementswhichincreasethesizeofopeningsthroughwhichdyescandiffuse.7.2.3ArraignmentofWorkingProcedureHeatsettingcanbedone:beforeanywettreatment,afterscouringandmercerizing,orafterdyeingofthefabric.7.3MechanismofThermosettingHeatsettingstressesintheamorphousregionsofthermoplasticfibers.Whenthefiberisheatedaboveitsglasstransitiontemperature,themoleculesintheamorphousregionscanmove,andthematerialcanbeformedintoanewshapes.Thus,creasethathavedevelopedinthefabriccanbepulledout,andthewidthofthefabriccanbechangedsomewhatintheheatsettingprocess.7.3MechanismofThermosetting

7.3.1BasicprincipleandbasiccourseBasicprinciple:

利用加热使纤维大分子链段的活动性增加，纤维网结构中弱的结合点被拆散，结构舒解，内应力被释放；在外力变形下冷却，重建新的结合力，使织物的形态得到稳定。Basiccourse1.纺织材料在加热下柔性化；2.柔性材料在外力下变形；3.变形下冷却使新的材料得到稳定。

刚性体

加热

柔性体

外力

柔性体

冷却刚性体7.3.2ChangeofMicrostructureDensity(degreeofcrystallization)Sizeofcrystalparticle涤纶长丝晶粒尺寸垂直于010面长度与定型温度的关系MechanismofThermosetting

ofPolyacrylonitrilefiber

蕴晶区结构:侧向有序,纵向无序。热定型时：蕴晶区含量不变，但其尺寸变大；非晶区取向度随温度而认为：热定型使非晶区的大分子因热运动加剧而重排，内应力消失，重建新联结点，蕴晶区完整性提高，纤维热稳定性提高。7.4AnalysisofProcessofThermosetting7.4.1TemperatureThetemperatureusedfordryheatsettingofpolyesterisusually180-220oC.Highersettingtemperaturegenerallygivesbetterdimensionalstabilityandresistancetopilling.However,thefabricincreasesinstiffnessandlosecreaserecoverycharacteristicswhensetathighertemperature.Lowertemperatureareusedforheatsettingfabricscontainingtexturizedyarnbecausethecrimpmaybelostiftheyarnisheatedtohighertemperature.Typicaldryheatsettingtemperatureare150-175

oCfortexturizednylonand160-180

oCfortexturizedpolyester.settingtemperatureshouldbehigher30-40

oCthanappointedtemperatureforpurepolyester(forT/C20

oC)7.4.1.1DimensionalthermalstabilityseealsoP.196Fig.7-11,7-12

收缩温度oC热定型后涤纶长丝织物在不同温度下的收缩率温度（oC）热定型温度对涤纶长丝织物尺寸热稳定性的影响热定型温度对锦纶66经编针织物尺寸稳定性的影响7.4.1.2wrinkleresistance(creaseresistance)7.4.1.3DyeingpropertyEffectofheatsettingtemperatureonsaturationvalueofdispersedyeonpolyester

Fig.Effectofheatsettingofpolyesterat230oCondyeingrate7.4.1.4evenessoftreatedtemperature7.4.2TreatedTime

TimeforheatupthetemperatureofheatedfabricsurfaceTimeforheatpenetratedthetemperatureofheatedfibers:2-15sec.Timeformolecularadjustthetemperatureofheatedmoleculeinfibers:1-2sec.Timeforcooling7.4.3

Tension/StrainWarpdirection:overfeedweftdirection:expending7.4.3.1tensioninfluencesuponthemechanicalproperties7.4.3.2tensioninfluencesuponthedyeingproperties7.4.3.3tensioninfluencesuponthefiber’sconfiguration

张力对涤/棉织物质量的影响

TemperatureoCRelationshipbetweenTemperature-Tension-DyeingPropertyEfixEoriProductMediumTemperature(0C)TimePA6hotair190±210-20ssaturatedsteam130±415-30min

hotwater12010-25minPA6.6hotair215±8