标准摘要
[中文适用范围]： 本文件规定了一种测定 pH 值的方法，该 pH 值由可通过热水从纸张、纸板或纸浆样品中提取的电解质来定义。 本文件适用于各种纸、纸板和纸浆。 当可提取的离子物质的量接近于零时，如在高度纯化的纸浆的情况下，该方法的精度变差，因为在对含有少量电解质物质的水中进行pH测量时遇到困难。 由于本文件中的提取是用蒸馏水或去离子水进行的，因此测得的 pH 值有时可能与在工厂工艺条件下测得的 pH 值不同（例如完全漂白的纸浆），其中各种类型的工艺用水（例如化学用水）使用经过处理的含有电解质的河水。 在这种情况下，可以使用 ISO 29681，因为它特别适用于原生纤维的漂白纸浆和离子强度较低的纸浆样品，对于这些样品，pH 值给出的与工厂条件相关的结果比通过本文件获得的结果更真实。 对于用于电气用途的纤维素纸，可以使用IEC 60554-2[5]中给出的方法。 [外文原描述]： This document specifies a method for the determination of the pH-value defined by the electrolytes extractable by hot water from a sample of paper, board or pulp. This document is applicable to all kinds of paper, board and pulp. As the quantity of extractable ionic material approaches zero, as in the case of highly purified pulps, the precision of the method becomes poor because of the difficulties encountered in making pH measurements on water containing little electrolytic material. Since the extraction in this document is performed with distilled or deionised water, the pH-value measured can sometimes be different (e.g. fully bleached pulp) from the pH-value measured under mill process conditions in which various types of process waters, such as chemically treated river water containing electrolytes, are used. In such cases, ISO 29681 can be used instead, as it is specifically applicable to bleached pulps from virgin fibres and to pulp samples having a low ionic strength for which the pH value gives more realistic results related to mill conditions than those obtained with this document. For cellulosic papers used for electrical purposes, the method used can be that given in IEC 60554-2 [5] .
英文名称Paper, board and pulps — Determination of pH of aqueous extracts — Part 2: Hot extraction