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1、,纸的染色与增白,Dyeing with Pergasol,Colour Space,It is helpful to think of Colour Space in terms of a colour tree:,The Lightness scale is arranged from top to bottom. The Lightness scale forms the first dimension of this colour space. The Lightness value of a colour is referred to by the letter L. Black w
2、ill have low L value and white will have a high L value.,CIElab Colour Space,CIElab colour scale identifies object colour using three coordinates (L*a*b*).,Another Cielab Colour Space,“a” is the red-green axis which is red on the positive side and green on the negative side. “b” is the yellow-blue a
3、xis which is yellow on the positive end and blue on negative end.,L* = Lightness,a* = red - green b* = yellow - blue,Colour Difference,. L*,a*,b* can be plotted in colour space and then used to calculate colour differences between the established product “standard” and a “batch”.,Colour Difference,A
4、 colour difference measurement is calculated by subtracting the L*a*b* of standard from the batch. For example:,The total colour difference between the Standard and the Batch can then be determined by calculating the difference between the samples in all three dimensions (L*,a* & b*).,纸料染色的目的： （1）生产
5、给定颜色的纸； （2）生产希望色调的白纸。,染料的种类： （1）颜料：各种无机颜料、合成无机、有机颜料； （）酸性染料：各种偶氮类钠盐、钾盐、芳香族有机盐； （3）碱性染料：各种含有甲基、已基、或异丙醇二氯酸盐、硫酸盐和草酸盐。 （4）直接染料：高度胶体化二偶氮类阳离子化合物； （5）荧光染料：磺酸基类；,造纸用各类染料的特性 1颜料（主要用在涂布胶料中）颜料特点 （1）对光稳定性好； （2）低的染料需求量； （3）与纤维不能直接亲合； （4）对纸的两面性有好处。 （6）压光着色性好； （7）与纤维结合能力低。,2酸性染料,特点： （1）水溶性好； （2）水溶液呈中性至弱碱性； （3）光固色适
6、中； （4）有利于改善纸的两面色泽； （5）对热敏感（偶氮）；,3碱性染料,特点： （1）阳离子性； （2）对纤维亲合力低； （3）染色效果好； （4）染料光亮； （5）中低光稳定； （6）酸、碱和氯中稳定性差； （7）对酸性物质亲合力高。,4直接染料 特点： （1）与纤维的亲合力高； （2）优良的光稳定性； （3）中等染色效果； （4）处理不当时有染色不均倾向； （5）PH值范围宽。,OHHO3SNHArRNH3+RNH3+N=N 5荧光增白剂 荧光增白剂大致可分为：二苯乙烯类、香豆素类、萘酰亚氨类、联苯类、唑灵类等。一般荧光增白剂中同时含有几种发色基团。,二 荧光增白剂的增白机理及性能 化
7、合物结构与荧光色调 荧光是一种光致发光的物理现象，当紫外光照射在某物体上，该物体吸收紫外光后会发射出不同强度的可见光，而当紫外光停止照射时 ，物体所发射出的光也 随之消失，这种光就是荧光。,不同化学结构的物质分子具有不同的能态。大多数分子在室温下均处在其最低能级，当光线照射到物体上，该物体的分子就会吸收与其特征频率相一致的光能，从基态跃迁到激发态的较高振动能级。 在短暂的时间内（约有10-8 秒），经内转换驰骋到激发态的最低振动能级上（平衡激发态），再由该处回落到基态的较高振动能级上，同时以光的 形式发出能量，这种光就是荧光。,作为增白几剂的化合物所反射的荧光应限于蓝光范围，这样才可作互补色用
8、于消除纸页中的黄褐色泽。它的吸收波长在335365nm 之间，反射的荧光波长在大多数情况下450nm左右，若吸收波长短于335nm，则反射的荧光偏红，若吸收的波长长于365nm，则反射的荧光偏绿。要调整色光，必要时可加入染料校正。,颜色要素：色相、饱和度、亮度。,（二）增白机理 白光可以产生多种混合单色光，这些单色光不一定包含有可见光波长。含有两种波长成份的混合光也可组成白光。如果调整两种色相差别较大的强度，可使它们混合后产生一白色光，这两种光的颜色成为互补色。 漂白往往给人一种带黄褐色泽的感觉，光反射在红、黄区域高于紫、蓝区域。增白给人一种微暗的白色感觉，反射光强度不高。但从它们的视觉意识来
9、讲，带蓝色色调比带黄色色调的白色显得更白。因此，在一定限度内，增加兰色光的饱和度就可以增加白色的感觉。这也是人们用于提高织物白度的理论依据。,（三）荧光增白剂的一般性能 荧光增白剂对纸料的处理类似于染料，但是它却与一般的染料性质不同，主要差异在于： （1）染料对纸张染色的给色量与染料的用量成正比，而荧光增白剂在低用量是它的白度与用量成正比，但超过一定极限时，再增加用量不仅白不可能提高，而且反而会使纸张带黄色。 （2）染料染色越深越能遮盖纸上的斑点而荧光增白剂的增白效果越好，尘埃等纸病愈明显。,（四）影响荧光增白剂性能的一些因素 1纸料中的残氯和酸会削弱增白效果； 2用量过大会使纸张泛黄； 3P
10、H值：阳离子型荧光增白剂pH9,吸光度明显下降，阴离子型荧光增白剂在酸性条件下吸光度急剧下降。 4溶液配制 3040的温水，水中不含Ca2+、Fe3+等离子二软水，随配随用； 5打浆度、接触时间、施胶剂类型和用量、树脂和淀粉类型。,（五）荧光增白剂的应用 1直接添加到纸料中增白； 2用于表面施胶； 3用于加工纸的表面涂布。 造纸工业常用的增白剂是Tinopal(liq.)，它是二氨基二苯乙烯四磺酸衍生物，外观白黄色透明的低粘度液体，年度为30cps ,相对密度1.19，可与水互溶，pH9.1，耐酸碱，有较好的乃光牢度。 a湿部纸张增白 注意：助剂添加顺序：荧光增白剂松香胶加填Alu，间隔大于1
11、0miu.，pH 4.59。 硫酸铝 6%，Tinopal ABP 0.051.0%, 滑石粉（CaCO3） 15%, 松香 0.51.2% b表面施胶 直接加入表面施胶液中，0.512 g/l; c涂布增白 需用辅助粘合剂。,DYEING METHODS CONTINUOUS,Advantage Dyes added late in the system Consistent contact time Fast shade control Safer people and process Less manpower Concentrated addition possible,Disadva
12、ntage Restricts order of addition Deep shades may be a problem May require system modifications (new addition points) Capital investment,HEADBOX,WHITEWATER,WIRE,CALCITE ALUM,POLYMER,CATIONIC DYESTUFF DYEFIX (TINOFIX,REFINE STOCK CHEST,SIZE CATIONIC STARCH,ANIONOIC DYES FWA,BROKE,CONTINUOUS DOSING PU
13、MP,POLYMIN,BLENDER,CENTRI SCREEN,WOOD/WASTE/LINTERS,Thickstock pump,POSSIBLE SETUP,STOCK FLOW with possible addition points for dyes and FWA,Levelbox,DYEING METHODS SIZEPRESS,- Very economical on smaller colour runs and deep shades - Leaves the circulation system clean and unsoiled,SIZEPRESS,Best fo
14、r Twosidedness Control,cont.,if paper exits the sizepress around one of the rolls then it is best to correct this by addition of a Mt Hope roll which first directs the paper directly out of the sizepress and then back into the machine direction may have to dam up both ends of the sizepress if open a
15、t the moment so that a true puddle is created often have to also correct the height of the puddles on either side of the paper sheet to be equal (= evensidedness),DYEING METHODS SPLIT (Batch / Continuous),70-80 % DYE added to pulper or mixing chest 20-30% DYE continuously added prior to fanpump ADVA
16、NTAGES QUICK SHADE CHANGES AND CORRECTIONS (On-line colour control, less off-spec colour ) DEEP SHADES EXTENDED CONTACT TIME MORE ECONOMICAL LESS FIXING AGENT NECESSARY LESS OFF- SHADE PRODUCTION BETTER HANDLING OF BROKE REQUIRES LOWER FIXING AGENT AMOUNTS,FIBRE QUALITY (INTEGRATED PULP / PAPER MILL
17、) FILLER (TYPE, AMOUNT AND QUALITY) WATER QUALITY (SOFT- OR HARD WATER) DYESTUFF AFFINITY / BEHAVIOUR pH - VALUE DYEING PROCEDURE (BATCH/CONTINUOUS/SPLIT) DYEING CONDITIONS (UNSIZED, ACID SIZED, NEUTRAL SIZED, a.s o.) ADDITIVES (FIXING-, RETENTION-,WET STRENGTH-AGENTS) BROKE (AMOUNT AND SHADE) FIBRE
18、 RECOVERY TEMPERATURE AND HUMIDITY,PARAMETERS INFLUENCING DYEING RESULTS IN THE WET END,The parameters influencing the dyeing,“Everything Affects Color, Color Affects Nothing”,Process variables affecting color: Furnish nature, quality, brightness, recycled fiber, broke, refining, Fillers type and qu
19、ality of clay, chalk . Additives retention aids, sizing, dye fixatives, wet strength, alum, Water quality hardness influences dye exhaustion,The parameters influencing the dyeing Cont pH dye “strength” is a sensitive function of pH Contact time dye “exhaustion” is function of contact (Addition Point) time Dye concentration especially where dilutions are used Fiber recovery clouration of fines Stock Temperature Temperature influences the dye off-take Dyestuff The selected dye itself,