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1、Paper Coating Techniques 造纸涂布新技术Presented for Daewoo Paper大宇纸业技术讲座 April 2003 by John Moore Chemco International John Moore 化联精聚化学Introduction前言We will review paper coating equipment, the basic concepts will be discussed along with:我们将回顾一下涂布的设备,并依次讨论一下其基本概念 - advantages in paper quality对纸张的优点 - disa
2、dvantages对纸张的缺点 - operational issues纸机操作的影响 These things are important to your ability to problem solve and provide detailed feed back to principle and internal customers like TMC.这些方面对于提高解决问题的能力,并提高反馈问题的能力都是很 有帮助的。Fundamentals page 1 基本原理 第一页Almost all coaters consist of two functions:所有的涂布机都具 有两种功
3、能:nApplication上料装置nmetering 计量装置Application consists of applying more material than is needed in the final product上料是指将过量的涂料涂到纸张表面Metering methods remove the excess in a way which leaves the desired coating quality at the desired production rate 计量是指将过量的涂料从纸层移除,达到需要的涂布量Fundamentals page 2 基本原理 第二页We
4、 will consider the four most popular coating methods: 我们将讨论四种比较常见的涂布方式:nBlade coating both bent and stiff 刮刀涂布,硬刮刀和软刮刀nAir Knife Coating 气刀式涂布nRod Coating 棒刀式涂布nMetering Size Press/Roll 计量式施胶涂布/辊式Blade vs Airknife vs Rod/Metering Size Press 刮刀式涂布和棒刀/计量式施胶涂布的比较Factors Affecting Coater Runnability 影响涂
5、布机运转的因素Application and Metering Two Normal Steps 上料和计量 两个基本的步骤Blade Coaters 刮刀式涂布Blade coaters are the most commonly used metering device in the paper & board industry 在造纸工业的涂布应用中刮刀式涂布是最常见的方式nridged blade硬刮刀nbent blade软刮刀Used with various application devices including: 使用不同的上料装置,包括:nroll applicator上
6、料辊nshort dwell短流着njet applicator喷射型Stiff Blade Bent Blade at Tip 硬刮刀 软刮刀刀尖工作情况Typical Operational Conditions for Blade Coaters刮刀涂布的典型工作条件Head angle 0刮刀角35 to 50 15 to 25Coating solids涂料固含量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
7、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 硬刮刀Ridged blade coater advantages硬刮刀涂布的优点nsmooth level surface Excellent roto & offset print 平整的纸面- 优异的凹版和胶版印刷性能ngood coat weight
8、 control at high speed or solids 高速或高固含量下的良好的涂布量控制nbest LWC when used with short dwell applicator 当用短留着型涂布设备时,非常适合轻涂纸LWCRidged blade disadvantages硬刮刀涂布的缺点npoor ability to achieve high coat weight at low speeds 在低速时很难达到高的涂布量nhigh coating de-watering at high blade pressure 刮刀压力越大,保水性越差Operational issu
9、es操作方面nblade lines/streaks 刮刀条痕nblade wear can be high 刮刀磨损严重Blade Coaters-Bent 刮刀涂布机 软刮刀Bent blade coater advantages 软刮刀涂布的优点nsame smooth coating as stiff blade 像硬刮刀一样的平整纸面nability to obtain high coat weight at low speed or solids 在较低的车速或固含量下,得到较高的涂布量ncan apply high coat weight on smooth substrates
10、 with few blade lines 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 blade 刮刀条痕较硬刮刀少Bent blade disadvantages软刮刀涂布的缺点npoor ability to achieve low coat weight at high speeds 在高速下较难达到高的涂布量nhigh coating dewatering at high blade angle/ pressure 在大的刮刀角度或加压时保水性能差Operational issuesnblade lines/
11、streaks 刮刀条痕nblade wear can be high 刮刀磨损严重Roll Applicator Trailing Blade Coater 辊式涂布- 整饰刮刀涂布机Coating/Application, Dwell, Metering 涂布/上料,留着,计量Blade Coater w/Short Dwell Applicator 刮刀涂布机/短留着上料装置Blade Load for Short Dwell vs Roll Applicator 短留着和喷射式涂布头的刮刀加压Coating/Application, Dwell, Metering 涂布/上料,留着,计
12、量Air Knife Coaters 气刀式涂布机AK coater advantages 气刀式涂布机的优点nuniform thickness coat important for optical uniformity 均一的涂层厚度,对保持均一的光学性能非常重要nversatile in coat weight and the uniform thickness is important for many functional coatings涂布量的灵活性和均一的涂层厚度可以适应多种涂布的需求AK coater disadvantages气刀式涂布机的缺点nrequires low v
13、iscosity/solids & thus high drying load 需要较低的粘度/固含量,因为干燥的需求比较大ncan have patterns 会形成花斑nentrained air and porous coatings空气会进入涂层形成中空的涂层Operational issues操作方面nlips become plugged especially at higher speed 喷嘴会堵赛,尤其是在高速时ncan only be used on low speed & coaters under 500 m/min 只能应用于低于500m/min的涂布机Airknif
14、e 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 棒刀式涂布机Rod coater advantages 棒刀式涂布机的优点nfree of blade lines 没有刮刀条痕nrugged/excellent for base coats 适合于底涂Rod coater disadvantages棒刀式涂布机的缺点ncoatings can have patterns 涂层易形成花斑nsolids or viscosity change coat weight 固含量
15、或粘度直接影响涂布量Operational issues操作方面nrod life is long compared to blade 棒刀的寿命高于刮刀ncoat weight control is difficult especially at high speed 涂布量的控制比较难-尤其在高速纸机上Elements of Rod Coater Jagenberg type 棒刀涂布机的组成 - JagenbergRod 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MSP coate
16、r advantages计量式施胶涂布nfree of blade lines没有刮刀条痕nrugged/excellent for base coats or LWC适合于底涂ncan run at speeds over 2000 m/min运转车速可以超过2000m/minncan coat two sides simultaneously同时两面涂布nlow capital cost成本低Rod coater disadvantagesnCD profile can be difficult CD向的横幅控制比较难ncoat weight control limited & sensitive to coating vis. 涂布量控制较难,对涂料粘度比较敏感Operational issuesnapplicator roll condition critical to good surface quality 上料辊的工作状况对纸张表面质量有很大影响Meterin