最新造纸涂布技术 ppt课件

1、最新造纸涂布技术根本原理根本原理n一切的涂布机都具有两种功能：nApplication 上料安装nmetering 计量安装nApplication consists of applying more material than is needed in the final productn 上料上料是指将过量的涂料涂到纸张外表是指将过量的涂料涂到纸张外表nMetering methods remove the excess in a way which leaves the desired coating quality at the desired production raten计量计量

2、是指将过量的涂料从纸层移除，是指将过量的涂料从纸层移除，到达需求的涂布量到达需求的涂布量1、典型的涂层厚度为5-20微米2、典型的单面涂布量5-20克/平方米涂布纸的分类nLightweight coated: 5-10 g/m2 per siden Single-coated, medium weight 8-16 g/m2 per siden Double-coated 14-26 g/m 2 per siden Triplecoated 24-40 g/m 2 per side.n固含量要高，以到达节省能量的目的n印刷纸典型的固含量50-70%n某些功能性的颜料涂布纸固含量10-30%n

3、随着纸机车速的提高，防止涂层里面出现空气是非常关键的目前涂布技术的开展n上料安装保证纸张上每个点被涂料覆盖n计量安装准确对纸张进展涂布涂布上料和计量分类上料系统上料安装应该具备的特征n使涂料盘外形与上涂辊一致，消除死角，浆系统内的涂料降低到最低限制n用水冷壁冷却外表促使结露水，以防止溢出物与喷溅物结垢硬化，从而方便清洗n支持刮刀架的横梁要有较大的截面以防止下弯，用水循环控制温度n有一组空气管支配的夹紧安装辊式涂布 APLICATION ROLL n运用于大多数纸张涂布n从车速小于500米/分钟1500米/分钟都能顺应组成-上涂辊 背辊 涂料盘和刮刀片n由两个不同直径的辊子组成，辊子外表被橡胶覆

4、盖，均是自动n背辊BACK ROLL直径大，速度=纸机车速n上涂辊(APPLICATOR ROLL)直径是背辊的30-40%，速度是纸机速度的15-25%n典型的辊间间隔是0.5-1.5mmn两辊之间的间隔n上料辊的速度n涂料的粘度关键参数涂布过程的三个阶段1、上料阶段-涂料和纸张接触2、驻留阶段-上料至计量之间3、计量阶段-有刮刀、棒式和气刀计量n在接触阶段2-5ms，压区内的涂料接受了压力脉冲，最大压力在05-4BARS，主要依托于车速、压区宽度和涂料粘度n由于压力存在，涂料滤饼开场构成；涂料中的液体浸透到纸张内部n当上料辊与纸张分别后，压力下降；压力甚至低于大气压，构成气穴n驻留期大约继

5、续20-50ms，依托于车速和辊的直径；在驻留期主要依托纸张的吸水脱除涂料中的水分。n在计量阶段，纸张上的涂料组成分两个部分：n1、几微米厚的涂料滤饼n2、在滤饼外表的液体层n n 滤饼层的厚度为2-4微米，相当于3-5克/平方米涂料；大约3-6层颜料积层！所以，辊式上料也称为 -长驻留上料涂布随着纸机车速的添加，进入压区、经过压区或回流到涂料盘的涂料添加，容易导致飞溅SPLASH和漏涂景象的发生！n涂层分别SPLIT，不能构成完全均匀的外表，取决于涂料的粘度和外表张力nSPLIT容易构成RIBBED PATTERN在纸张外表和涂布辊外表n纸机车速越高，RIBBED 又导致DROPLETSD

6、的构成，最终涂布纸质量发生变化n处理RIBBED 的方法：采用JET APPLICATION放射上料安装短驻留涂布SDTA短驻留上料安装n对纸张强度要求没有长驻留高n刮刀接受的负荷小n纸张断头少SDTA的脱水n压力n时间n原纸的吸受n一定温度下，涂料对脱水的抵抗力n温度n由于短驻留脱水时间，在驻留区接受的压力小，所以不会导致涂料的剧烈脱水n短驻留回流压区与计量刮刀之间的间隔为30-50mmn 当纸机车速为1000-1500m/min时，驻留时间为1.2-3毫秒；与600mm长驻留相比，驻留时间只需其1/10n短驻留原纸回湿景象少n在涂布头处纸张的强度损失少两种驻留上料的比较n由于短驻留上料涂料

7、失水不严重，涂层滤饼不容易构成n假设构成涂布滤饼，那么在刮刀处涂料的固含量比泵送过来的新颖涂料要高，结果导致涂料头的压力上升，结果导致过多的涂布缺陷产生和纸张断头。短驻留对纸张质量的影响n短驻留主要用于低、中量涂布6-11克/平方米n涂料固含量为59-64%短驻留为什么产生比较平滑的涂层外表？ fiber roughening短驻留条痕short dwell streaks 短驻留涂布量为15克/平方米；长驻留涂布和放射涂布要高20克/平方米消除短驻留涂布条痕的措施放射上料JET APPLICATOR Voith Dynamic Jetflow Cn辊式涂布的取代产品n两把刮刀，使得控制困难；

8、纸张张力不容易控制Valmet Opticoat Duo Valmet Opticoatn上述几种放射上料涂布难以在实践消费中运用。Another example of premetered jet applicator (Valmet Opticoat).Free jet applicatorsFREE JET APPLICATOR的任务原理Backing rollNozzle gap 0.6 - 1.2 mmPremetered colour150 - 200. ml/mColour supplyPaper20- 40n消除了FILM SPLIT 和溢流，喷出的层状涂料均匀一致n影响要素主

9、要包括：n 流动速率n 堰板宽度n 放射角n 放射间隔计量安装Fundamentals page 2 根本原理根本原理 第二页第二页nWe will consider the four most popular coating methods:nBlade coating both bent and stiffn刮刀涂布，硬刮刀和软刮刀nAir Knife Coatingn气刀式涂布nRod Coatingn棒刀式涂布nMetering Size Press/Rolln计量式施胶涂布/辊式Blade vs Airknife vs Rod/Metering Size Press刮刀式涂布和棒式/

10、计量式施胶涂布的比较影响涂布机运转的要素刮刀式涂布刮刀式涂布nBlade coaters are the most commonly used metering device in the paper & board industryn在造纸工业的涂布运用中刮刀式涂布是最 n 常见的方式nridged blade 硬刮刀nbent blade 软刮刀Typical Operational Conditions for Blade Coaters刮刀涂布的典型任务条件刮刀涂布的典型任务条件Head angle 0刮刀角35 to 50 15 to 25Coating solids涂料固含

11、量45 to 7045 to 70Coater Speed 涂布车速To 2000 m/min200 to 1200 m/minCoating Visc.涂料粘度800-3000800-1500Best suited for最适合于LWC ,pre-coats and low coat weightBoard and high coat weightsBiggest concern最关系到Blade streaks刮刀条纹Blade streaks刮刀条纹Stiff Blade硬刮刀Bent Blade软刮刀Blade Coaters-Ridged刮刀涂布机刮刀涂布机 硬刮刀硬刮刀nRidge

12、d blade coater advantages硬刮刀涂布的优点n平整的纸面- 优良的凹版和胶版印刷性能n高速或高固含量下的良好的涂布量控制n当用短留着型涂布设备时，非常适宜轻涂纸LWCStiff BladeBent BladeImmobilizedcoating layerCoating colourPaperP 5.28-BLAD-TE-0152eBlade Operation Modus67blade angleadjustmentblade loadadjustmentDynaBlade CCoat weight control68nRidged blade disadvantage

13、sn硬刮刀涂布的缺陷n在低速时很难到达高的涂布量n刮刀压力越大，保水性越差nerational issuesn 操作方面nblade lines/streaksn刮刀条痕nblade wear can be highn刮刀磨损严重Blade Coaters-Bent刮刀涂布机刮刀涂布机 软刮刀软刮刀nBent blade coater advantages n 软刮刀涂布的优点nsame smooth coating as stiff bladen像硬刮刀一样的平整纸面nability to obtain high coat weight at low speed or solidsn在较低的

14、车速或固含量下，得到较高的涂布量ncan apply high coat weight on smooth substrates with few blade linesn在光滑的底面上得到高的涂布量，刮刀条痕较少nless problems with streaks than stiff bladen刮刀条痕较硬刮刀少nBent blade disadvantagesn软刮刀涂布的缺陷npoor ability to achieve low coat weight at high speedsn在高速下较难到达高的涂布量nhigh coating dewatering at high bla

15、de angle/ pressuren在大的刮刀角度或加压时保水性能差nOperational issuesnblade lines/streaksn刮刀条痕nblade wear can be highn刮刀磨损严重Influence Factors Coat Weight g/mnRaw paper parameters: nAbsorbancy (Cobb test)nfurnishnporositynCoating colour parameters:nViscosity mPa.snsolids content %nbindersnPre-metering parameter:nCo

16、lour pump rate m/hnMetering element parameters:nMetering blade angle nBlade load through spacer unit setting mmnBlade thickness72Air Knife CoatersAir Knife Coaters气刀式涂布机气刀式涂布机nAK coater advantages n气刀式涂布机的优点nuniform thickness coat important for optical uniformityn均一的涂层厚度，对坚持均一的光学性能非常重要nversatile in

17、coat weight and the uniform thickness is important for many functional coatingsn涂布量的灵敏性和均一的涂层厚度可以顺应多种涂布的需求nAK coater disadvantagesn气刀式涂布机的缺陷nrequires low viscosity/solids & thus high drying loadn需求较低的粘度/固含量，由于枯燥的需求比较大ncan have patternsn会构成花斑nentrained air and porous coatingsn空气会进入涂层构成中空的涂层nOpera

18、tional issues操作方面nlips become plugged especially at higher speedn喷嘴会堵赛，尤其是在高速时ncan only be used on low speed & coaters under 500 m/minn只能运用于低于500m/min的涂布机Airknife Coater气刀式涂布机Airknife Coater double knife w/blowoff pan气刀式涂布机- 带吹气面板的双刀型Rod Coaters棒式涂布机棒式涂布机nRod coater advantages n棒刀式涂布机的优点nfree of

19、 blade linesn没有刮刀条痕nrugged/excellent for base coatsn适宜于底涂nRod coater disadvantagesn棒式涂布机的缺陷ncoatings can have patternsn涂层易构成花斑nsolids or viscosity change coat weightn固含量或粘度直接影响涂布量nOperational issuesn操作方面nrod life is long compared to bladen棒刀的寿命高于刮刀ncoat weight control is difficult. especially at hig

20、h speed涂布量的控制比较难-尤其在高速纸机上nElements of Rod Coater Jagenberg type棒刀涂布机的组成 Rod Affect on Coating Smoothness棒刀对涂层平滑度的影响Metering Size Press Coaters 计量式施胶涂布计量式施胶涂布Speedsizer: Principle arrangement and componentsApplicatorMetering elementReturn flowRest film(10 - 40 %)Web tension50 - 500 N/mAirturnApplicat

21、orroll 800 - 1600 mmFLRoll nip 15 - 45 mmLine load (N/m)Roll cover (P & J), 15 - 20 mmPremetered film5-50 ml/m2 (= 100 %)FL8586SpeedSizer AT web run87施胶棒计量施胶棒转动 液压马达 施胶棒从两边转动 施胶棒与施胶辊转动方向相反 转动速度 - 50 - 100 rpm 外表施胶 - 150 - 200 rpm 涂涂料用于涂布和外表施胶的施胶棒 - 平滑的施胶棒直径12-35mm - 带槽的施胶棒直径9.83-15mm and 16-25mm膜施胶任务原理：1 估计量施胶辊外表的湿膜量2 将湿膜传送到纸幅上3 不固定的膜层分别4 固定的膜层的水准丈量膜在施胶辊上的传送带槽的施胶棒：施胶量丈量外表施胶沟纹棒 施胶量每面0.5-4 g/m2 固含量3-15 % 涂料光滑棒 涂布量范围 2 - 12 g/ m/side 固含量 40 - 68 % 车速 200 2000 m/min 膜传送涂布，难到达高涂布量nMSP coater advantagesn计量式施胶涂布nfree of blade