《亚马逊卫生纸洗涤》由会员分享，可在线阅读，更多相关《亚马逊卫生纸洗涤（8页珍藏版）》请在金锄头文库上搜索。
1、104Pulp Picture 4 shows the inevitable result of that sticky: a felt-related sheet hole. Stickies (and other organic contaminants) have three possible “life cycles” in a paper mill: Small stickies deposit on a collecting surface, such as a Uhle box cover. In this case, there is minimal agglomeration
2、 in the stock system and deposits build gradually. Small stickies agglomerate in the stock and/or water systems, then form a discrete deposit. This is the most common source of fabric contamination, and is documented in Picture 3. Large stickies enter the stock system via the incoming stock and form
3、 discrete deposits. This case is most often found in recycled fibre mills that lack proper fine screens or in mills that allow adhesives to enter their converting broke stream. It is worth noting that some “water soluble” converting tapes can become insoluble over time and lead to serious problems o
4、n the paper machine. While stickies can- and should- be controlled in the stock system, they can also be addressed on the Tissue machine.Wet strength As wet strength agents are functional chemicals, there is little choice as to their use. It is analogous to sizing agents in fine paper mills: it is n
5、ot a question of whether or not the additive will fill the felt; it is a matter of minimizing its impact on quality and productivity. Wet strength additives are cationic, so unretained wet strength polymer is substantive onto felt fibres, promoting initial deposition in the felt. The main reason tha
6、t wet strength is such a serious problem for felt cleanliness is its o 消泡剂 其他杂物 o 泄漏的润滑油 o 外来物质 o 动植物的残骸等 就大多数的生活用纸厂商而言，造成毛布运行问题的原因是粘 性物质，或湿强剂和残留的氧化剂。粘性物质 图三是典型的毛布被粘性物质污染的图片，图四是毛布上与粘 性物质相关的原因所造成的纸面破孔的结果。在纸厂中，粘性物质 （和其他的有机污染物质）有三种可能的循环方式： 小的粘性物质沉积在管线内壁或机架的表面，如真空吸水箱 的面板上。在这种情况下，粘性物质很少会返回到浆料系统并结成 较大的粘块和
7、逐渐的积累变成大的沉积物。 细小的胶粘物在浆料或白水系统中结聚成块，并形成离散的 沉积物。这是大多数成型网和毛布污染物的来源，请参见图片三。 来自于原料中的大块的沉积物进入到浆料系统中，形成离散 的沉积物。这在使用废纸作为原料的纸厂中是很常见的，由于不恰 当的压力筛或某些胶粘物进入到后加工过程中产生的损纸中。在某 些情况下，那些原来是水溶性的物质会随着时间的推移而转变成不 溶于水的沉积物，并导致一系列的纸机运行问题。 当在浆料中胶粘物受到控制以后，它们同样可以出现在生活用 纸的纸机上。图一：正常的毛布的 横截面 Picture 1: Cross section of undamaged fel
8、t图二：已经受到损伤 的毛布的横截面 Picture 2: Cross section of damaged feltWritten by Chris Rozett Technical Marketing Manager Amazon Papyrus Chemical www.amazon-106Pulp the hot Yankee surface encourages cross linking in the felt. Every time the sheet is pressed against the Yankee by the felt, wet strength molecule
9、s cross link in the felt, becoming more and more difficult to remove. It is extremely difficult to remove cross linked wet strength from the felt. The most effective cleaning agents are oxidizers, such as sodium hypochlorite (NaOCl). Unfortunately, NaOCl has the unwanted side effect of damaging felt
10、 fibres. In severe cases of wet strength felt filling, the mill is faced with a lose-lose proposition: operate with a dirty felt or damage the felt (and reduce its useful life) by cleaning it. Most people who have spent time in a tissue mill have seen the effect of a dirty felt on the Yankee creping
11、 program: localised loss of coating on the dryer. When the creping program fails, several problems can become apparent: Poor and uneven creping Poor roll building with corrugation and wrinkles Loss of protection of the Yankee surface Picture 5 shows an example of carbon marking on a tissue sheet. In
12、 this case, the creping blade is contacting the dryer surface, leading to a loss of metal from the Yankee which then deposits on the sheet. While carbon marks can lead to the rejection of individual rolls of tissue, they are an indication of a more serious problem: Yankee damage. Degrading the surfa
13、ce of the Yankee leads to premature Yankee grinding, a time consuming and costly procedure.Oxidizers Oxidizers are a concern not for filling felts, but for the way they can degrade felt fibres. There are three main ways in which oxidizers are introduced into the papermaking system: Reworking wet str
14、ength broke Using high concentrations of oxidizing biocides to treat the stock or fresh water Removing wet strength from felts Reworking wet strength broke is the most likely way in which felts can be damaged by oxidizers, as NaOCl (or other chemistries) are introduced in high concentrations to the
15、pulper. If the residual oxidizer is not neutralized with a suitable scavenger, a large “slug” of oxidizer can reach the paper machine, stripping the Yankee coating and damaging felt fibres. Picture 6 shows an example of chemical damage to fibres. Notice the fibrillated look of the plastic fibres. Ax
16、ial degradation of fibres is a classic indication of chemical damage and is easily distinguished from mechanical wear. Chemical damage leads to loss of batt fibres- batt fibres are the most susceptible to chemical damage because of their high relative surface area- and a loss of felt integrity.湿强剂 湿强剂是一种功能性的化学药品，在纸厂的应用过程中与施胶 剂相类似有少量的挑选余地。它并非一定会影响到毛布的运行和表 现，如果控制合适，它们对纸的品
