Chapter7 Thermosetting(HeatSetting)Lecturer:Prof.Dr.Yankelu7.1IntroductionThedimensionalstability,dyeability,andotherpropertiesofthermoplasticfibersareaffectedbyrepeatedheatingandcooling.Themainpurposesofheatsettingareasfollows:Tostabilizethematerialtoshrinkage,distortion,andcreasing,Toimprovethedyeabilityoffabrics.定型三大內(nèi)容：棉的絲光合纖熱定型樹(shù)脂整理合成纖維在紡絲成型中熱處理時(shí)間較短，存在內(nèi)應(yīng)力；在織造過(guò)程中纖維、紗線受力也存在內(nèi)應(yīng)力。因此，合纖織物遇熱易發(fā)生皺縮，織物幅面失去平整，印花花紋改變，成衣尺寸失去穩(wěn)定性。定型的目的：消除織物上已有的皺痕和提高織物的熱穩(wěn)定性（主要指高溫條件下的不收縮性）和不易產(chǎn)生難以去除的折痕。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:

利用加熱使纖維大分子鏈段的活動(dòng)性增加，纖維網(wǎng)結(jié)構(gòu)中弱的結(jié)合點(diǎn)被拆散，結(jié)構(gòu)舒解，內(nèi)應(yīng)力被釋放；在外力變形下冷卻，重建新的結(jié)合力，使織物的形態(tài)得到穩(wěn)定。Basiccourse1.紡織材料在加熱下柔性化；2.柔性材料在外力下變形；3.變形下冷卻使新的材料得到穩(wěn)定。

剛性體

加熱

柔性體

外力

柔性體

冷卻剛性體7.3.2ChangeofMicrostructureDensity(degreeofcrystallization)Sizeofcrystalparticle滌綸長(zhǎng)絲晶粒尺寸垂直于010面長(zhǎng)度與定型溫度的關(guān)系MechanismofThermosetting

ofPolyacrylonitrilefiber

蘊(yùn)晶區(qū)結(jié)構(gòu):側(cè)向有序,縱向無(wú)序。熱定型時(shí)：蘊(yùn)晶區(qū)含量不變，但其尺寸變大；非晶區(qū)取向度隨溫度而認(rèn)為：熱定型使非晶區(qū)的大分子因熱運(yùn)動(dòng)加劇而重排，內(nèi)應(yīng)力消失，重建新聯(lián)結(jié)點(diǎn)，蘊(yùn)晶區(qū)完整性提高，纖維熱穩(wěn)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

收縮溫度oC熱定型后滌綸長(zhǎng)絲織物在不同溫度下的收縮率溫度（oC）熱定型溫度對(duì)滌綸長(zhǎng)絲織物尺寸熱穩(wěn)定性的影響熱定型溫度對(duì)錦綸66經(jīng)編針織物尺寸穩(wěn)定性的影響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

張力對(duì)滌/棉織物質(zhì)量的影響

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

hotwater12010-25minPA6.6hotair215±8