AATCC-湿法加工纺织品水萃取液PH值的测定

1 目的和范围

1．1 洗涤或漂洗过的纺织品都可用来这种方法测定其PH值。

1．2 为了确保检测质量，影响PH值的化学物质必须从待检验样品水萃取液中排除。 2 原理

样品在蒸馏水或去离子水中蒸馏。待水冷却到室温，测定PH值。 3 术语

3．1漂白，名词一通过氧化还原化学处理方法除去纺织品颜色。

3．2酸碱度，名词一其为溶液中氢离子浓度对数的负值，表示溶液酸性或碱性。数值等于7的为中性溶液，数值增大表示碱性增大，数值减小表示酸性的增大。PH值范围一般在0到14之间。

3．3湿法加工，名词一在纺织品生产中的一个专用集合术语，包括制备、染色、印花、整理。纺织原料用液体处理(通常是水)，也可用溶液中的或分散在液体中的化学物质来处理。 4 安全预防措施

注意：这些安全措施仅仅起信息提示作用，辅助测试过程，并不包括所有细节。在测试过程中，使用者应该采取安全合理的技术处理所用材料，咨询生产商具体的材料安全数据单和别的生产商的意见。必须咨询和遵循所有OSHA的标准和规定。

4．1应养成好的实验习惯。在实验室的任何区域都应带安全防护眼镜。 4．2必须小心处理所有的化学药品。 5 使用和限制

5．1测定PH值，我们可以了解湿法加工纺织品是否适宜后面的染色、整理工序和评价加工过程洗涤、中和效果。

5．2这个方法还必须联合AATCC测试方法144，湿法加工纺织品中的碱含量：测定所存在全部碱的量。因为从PH值所反映酸碱的量不一定确切，精确值可能被存在的强的缓冲剂所掩盖。 6 设备与原料

6．1精确到0.1的PH计。 6．2 400ml的玻璃烧杯。

6．3 PH值为4.0、7.0、10.0等的缓冲液， 7 校准

7．1根据制造者的说明书校准PH计。选择与待检验样品PH值接近的缓冲液来校准。 8 样品

8．1选择10g样品待测。如果制品密度太小，则把样品剪成小块。

9 实验步骤

9．1在烧杯中以中等速度煮250ml蒸馏水10分钟，浸人样品，用表面皿盖住，再煮10分钟。

9．2冷却至室温，用镊子取出样品，并把样品上的液体滴回烧杯中。 9．3测定PH值。 10 评价分析

10．1水萃取液PH值取决于织品先前的化学处理，洗涤水的PH值，以及洗涤操作的效率。

10．2通常，样品在碱中煮织品水萃取液PH值高于漂白织品水萃取液的PH值。如果样品漂白后又洗涤PH值会更低。

10．3高PH值样品有变黄、便暗，色牢度变差和树脂整理剂和软化水消耗的减小的趋势。

11 精密度与偏差 11．1精密度

11．1．1在1993年后期，一项多个实验室进行的研究完成。五个实验室，分别有两个操作员对4种织物进行3种不同的测定。以前没有对参与实验室的相对水平作评估。 11．1．2对这些数据(5*2+3*4=120)进行分析得出各组分间方差如下： 实验室间偏差 0.1203 同一实验室的操作员间偏差 0.0150 同一实验室的同一操作员测定同一材料的偏差 0.0188

11．1．3 表一给出11．1．2中数值置信概率为95%的临界极差。

表1再现性临界极差一置信水平为95%漂白织物水萃取液PH值得测定 N 1 2 4 8 单个操作员 0.38 0.27 0.19 0.13 实验室内 0.51 0.43 0.39 0.37 实验室间 1.09 1.05 1.04 1.03

11．1．4 N次测定的两个平均值的极差，作为适宜的精密参数，应达到或超过表中值(在95%置信水平下测定)。 11．2偏差

11．2．1在某种程度上，这种方法所采用的PH计所测定的值与真实值相符。目前为止，本方法所测过的织物PH值没有偏差。故在这次研究中，没有用任何独立，有鉴定性的分析方法来分析偏差的存在与否。

1 Purpose and Scope

1.1 This test method determines the pH of wet processed textiles either scoured or

bleached.

1.2 To make a quantitative determination, the chemicals which influence pH must be removed from the textile specimen, collected as a water extract and then accurately measured by a pH meter．

2 Principle

2.1 The specimen is boiled in distilled or deionized water．The water-extract is cooled to room temperature and the pH is determined.

3 Terminology

3.1 bleaching，n．—elimination of unwanted coloring matter from a textile substrate by oxidative or reductive chemical treatment.

3.2 pH，n．—the negative logarithm of the effective hydrogen ion concentration or hydrogen ion activity in gram equivalents per liter used in expressing both acidity and alkalinity oil a scale whose values run from 0-14 with 7 representing neutrality，numbers less than 7 increasing acidity and numbers greater than 7 increasing alkalinity．

3.3 wet processing．n．—in textile manufacturing, a collective term for process included in preparation，dyeing, printing and finishing in which the textile material treated with a 1iquid, normally water, or with chemicals in solution or dispersion in a liquid． 4 Safety Precautions

NOTE: These safe precautions are for information purposes only．The precautions are ancillary to the testing procedures and are not intended to be all inclusive. It is the user’s responsibility to use safe and proper techniques in handling materials in this test method. Manufacturers MUST be consulted for specific details such as materials safety data sheets and other manufacturer’s

recommendations. All OSHA standards and rules must also be consulted and fo1lowed.

4.1 Good laboratory practices should be followed. Wear safety glasses in a11 laboratory areas.

4.2 All chemicals should be handled with care．

5 Uses and Limitations

5.1 pH can be used to determine the suitability of wet processed textiles for subsequent dyeing and／or finishing operations or to evaluate the washing and／or neutralizing efficiency following any wet processing operation．

5.2 This method should be used in conjunction with AATCC Test Method 144, Alkali in Wet Processed Textiles：Total, in order to quantitatively determine the amount of an alkali present While pH gives an indication of relative alkali or acid content，the exact amount can be masked by the presence of strong buffering agents．

6 Apparatus and Materials

6.1 pH meter with 0.1 unit graduations． 6.2 Beakers，glass，400 mL.

6.3 Buffer solutions，pH 4.0，7.0，10.0 or others as needed．

7 Calibration

7.1 Calibrate the pH meter in accordance with the manufacturer’s

instructions．Select buffer solutions for calibration which are in the estimated range of the specimens’ pHs．

8 Specimens

8.1 Use a 10±0.1g specimen of the material to be tested. If the weight per square yard of the fabric is excessively low, cut the sample into small pieces.

9 Procedure

9.1 Boil 250 mL of distilled water at a moderate rate for 10 min．Immerse the specimen，cover the beaker with a watch glass and boil for an additional 10 min. 9.2 Allow the covered beaker and contents to cool to room temperature. Remove the specimen with tweezers, allowing the excess liquid to drip back into the extract．

9.3 Determine the pH of the extract using a pH meter operated according to manufacturer’s instructions.

10 Evaluation

10.1 The pH of the water-extract depends on the chemical treatment previously given the textile，the PH of the wash water，and the efficiency of the washing operation.

10.2 Normally，the pH of water extract will be higher after caustic boiling than after bleaching．If the textile is scoured after bleaching，the pH may be lower． 10.3 Textiles with high pH values may exhibit yellowing tendencies，create shade changes，alter the exhaustion and fixation of dyes，and produce a decrease in the cure of resin finishes or exhaustion.

11 Precision and Bias

11.1 Precision．

11.1.1 In late 1993，an interlaboratory study was completed，which included five 1aboratories，two operators in each，running three determinations per fabric, on four fabrics．No prior assessment was made of the relative level of performance of the participating laboratories．

11.1.2 Analysis of the data set (5×2×3×4=120 values)yielded components of variance as follows:

Laboratories 0.1203

Operators within laboratories 0.0150 Specimens within materials，laboratories and operators 0.0188 11.1.3 Table I indicates the critical differences calculated using the values in 11.1.2.

Table I Critical Differences for TWO Averages一95% Probability Level

pH of Water—Extract from Bleached Textiles N Single Operator Within Laboratory Between Laboratory

1 0.38 0.51 1.0

9

2 0.27 0.43 1.0

5

4 0.19 0.39 1.0

4

8 0.13 0.37 1.0

3

11.1.4 Differences between two averages of N determinations, for the appropriate precision parameter should reach or exceed the table value to be statistically significant at the 95% probability 1evel． 11.2 Bias.

11.2.1 To the extent the pH meter used in this test method is capable of measuring values of pH that are consistent with true values of pH，the determination of the pH of the water-extract from a

bleached textile，using this test method, has 130 known bias．During this study，no determination was made of the true value of this properly by an independent, referee analytical method for the purpose or establishing presence or absence or absence of bias. 关键词： PH值 湿法 英文名称：

pH of the Water-Extract from Wet Processed Textiles

2 0.27 0.43 1.0

5

4 0.19 0.39 1.0

4

8 0.13 0.37 1.0

3

11.1.4 Differences between two averages of N determinations, for the appropriate precision parameter should reach or exceed the table value to be statistically significant at the 95% probability 1evel． 11.2 Bias.

11.2.1 To the extent the pH meter used in this test method is capable of measuring values of pH that are consistent with true values of pH，the determination of the pH of the water-extract from a

bleached textile，using this test method, has 130 known bias．During this study，no determination was made of the true value of this properly by an independent, referee analytical method for the purpose or establishing presence or absence or absence of bias. 关键词： PH值 湿法 英文名称：

pH of the Water-Extract from Wet Processed Textiles

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