英文版 BOPP薄膜 简介

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1、ProductApplication&ResearchCentreMumbai1BiaxiallyOrientedPolypropyleneFilm(BOPP)Manyoftheuniquecharacteristicsofpolypropyleneenhanceitsutilizationintheapplicationoffilm.Themainapplicationforpolypropylenefilmarethepackagingoffood,textilesandtobaccoproducts.BiaxiallyOrientedFilm(BOPP)Biaxialorientat

2、ionisaprocessinwhichacontinuouscastfilmisheatedtobringittoastretchabletemperatureandthereafteritisstretchedinmachineandthenintransversedirection.Biaxialorientationofpolypropylene(BOPP)filmisdonebytwomethods·Tenterframeprocess·DoublebubbleprocessTenterFrameProcessTenterframeprocessisaveryexpensivew

3、ayofprocessingBOPPfilm.Howeverithasbecomepopularduetohigherproductionratewithverythinandwidewidthfilm(Fig.1)ExtrudersExtruderswith150to200mmdiascrewshavingL/Dof26:1to30:1aremorepopular.Dies600to1500mmwidecoathangertypeofdiesareusedTheTenterFrameProcess3Casting&QuenchingThemoltenpolymerextrudedfrom

4、thedieisplacedagainstachillrollormultiplechillrolls.Themostpopularbeingcastingontoachillrollpartiallysubmergedinawaterbath.Thechillrollandwaterbathtemperaturesaregenerally20to25°C.Usually,thesechillrollsare1000to2000mmindiameterandapproximately1000to1500mmwide.Thesurfaceofthechillrollmustbeverysmo

5、oth;pittingorirregularitiesonthesurfaceoftherollerwillinfluencethefilmquality.Anairknifeisusedtoforcepropercontactofmoltenpolymeragainstthecastingroll.Thecooledwebproceedstowardsthemachinedirectionorientationsection.MachineDirectionOrientation(MDO)Thebasesheetisalternativelyheatedbypassingitoverth

6、eheatedrollers(145-150°C)toachieveuniformheatingofwebthroughoutitsthickness.Theserollersareusuallysmallerindiameter(450to600mm)comparedtothecastingdrums(chilledrolls).Whenthefilmreachesthenecessarystretchingtemperature,itispassedoveraseriesofstretchingrollswhichareusuallyarrangedinpairs.Eachpairha

7、sarubberniprolltopreventslippingofthewebwhilestretching.Thesefirstsetofniprollersarerunataspeedsimilartopreheatrollers.Thenextsetofrollersareoperatedathigherspeedsthanthefirstsetofniprollers.Usuallythestretchrati