Shaanxi Dachang Textile Co., Ltd.

Shaanxi Chang Da Textile Limited Company

NEWS
What about textiles with substandard pH?
| 作者: changda001 | 发布时间: 2019-10-22 | 467 次浏览 Source: | Author: changda001 | Published: 2019-10-22 | 467 views 分享到: | Share to:
PH value is a very important quality indicator of textiles, and it is a mandatory indicator of GB18401-2010 National Basic Technical Safety Standards for Textiles. Unqualified pH value is also the most common quality problem in textile processing and trade, which is causing more and more problems. People's attention, this article will discuss with you how to control the pH value of textiles.

1. Definition of pH:

The pH value is pH, and human skin is weakly acidic. Under these environmental conditions, the invasion of germs can be prevented. Therefore, if the pH value of the textile is between slightly acidic or neutral, it will help protect human health. On the contrary, the pH value of the textile is too high. High or too low will damage the balance and resistance of the skin, which may cause skin allergies or induce infections and lead to bacterial invasion.

2, the requirements of the pH limit:

Product level

GB-18401-2010

Oeko-tex-100

Infants

4.0-7.5

4.0-7.5

Direct skin contact

4.0-8.5

4.0-7.5

Indirect contact

4.0-9.0

4.0-9.0

Decoration

no request

4.0-9.0

3. Source of abnormal pH:

The main reason is that the textile has insufficient pH control during the dyeing and finishing process, insufficient acid neutralization after wet treatment, or incomplete cleaning, and the dyeing and finishing process that easily causes abnormal pH is mainly alkali reduction, polyester printing washing, reactive printing washing, and cotton Desizing, scouring and mercerizing.

4. Comparison of different methods for measuring PH value of textiles:

(1) Chinese Standard (GB / T 7573-2009)

Weigh 3 2 ± 0.05g samples, cut them into 5 × 5 mm small pieces, put them into a flask containing 100ml of distilled water, shake the flask to fully wet the samples, place the flask on a shaker and shake 2 After an hour of ± 5 minutes, directly measure the pH of the water extract (excluding fabric) at room temperature using a pH meter. Do three tests on each sample, and take the average of the second and third sample results as the final result. Accurate to 0.1.

(2) European Union standard (EN 1413-1998)

Weigh three 2 ± 0.05g samples, cut them into 5 × 5 mm pieces, and place them in a flask containing 100ml potassium chloride solution (0.1mol / L) or 100ml distilled water. Shake the flask to make the sample sufficient Wet, place the flask on a shaker for 2 hours, and then directly measure the pH of the water extract (excluding fabric) with a pH meter at room temperature. Perform 3 tests on each sample, take the second and third The average value of the sample results is taken as the final result and is accurate to 0.1.

(3) Japanese standard (JIS L 1096-1999)

Weigh 5 ± 0.1g sample, cut it into 1 × 1mm pieces, boil it in 50ml distilled water and keep it for 2 minutes, put the sample in the flask, shake the flask to fully wet the sample, and let it stand at room temperature. Set the sample for 30 minutes and remove the sample. When the temperature of the water extract reaches 25 ± 2 ° C, use a pH meter to directly measure the pH of the water extract to an accuracy of 0.1.

(4) American Standard (AATCC 81-2001)

接测定水萃取液的PH值,精确至0.01。 Weigh 10 ± 0.1g sample, cut it into small pieces, boil it in 250ml distilled water and keep it for 10 minutes, put the sample in the flask, shake the flask to fully wet the sample, continue boiling for 10 minutes, and cool After reaching room temperature, remove the sample and directly measure the pH value of the water extract with a pH meter , accurate to 0.01.

standard

Standard name

Sample required weight / g

Size / mm

Extraction reagent

Extraction method

Extraction time / minute

China

GB / T 7573-2009

2 ± 0.05

5 × 5

100ml distilled water

Shake at room temperature / 3 samples

60

EU

EN 1413-1998

2 ± 0.05

5 × 5

100ml potassium chloride solution

Or 100ml of distilled water

Shake at room temperature / 3 samples

120

Japan

JIS L 1096-1999

5 ± 0.1

1 × 1

50ml boiled distilled water

Leave to boil / 1 sample after boiling

30

United States

AATCC 81-2001

10 ± 0.1

no request

250ml boiled distilled water

Boiled / 1 serving

10

PH value of water extraction solution of cotton fabric under different determination standards:

Sample

PH value measured by different standards of the same sample

China

EU

Japan

United States

1 # white

7.10

7.2

8.3

8.52

2 # gray

7.00

7.1

8.5

8.76

3 # blue

6.70

7.0

8.1

8.14

4 # Red and white lattice

6.50

6.7

7.3

7.47

5 # dark green

7.20

8.0

8.8

9.20

6 # Brown

6.70

6.9

8.4

8.56

7 # dark blue

7.10

7.2

8.2

8.31

8 # black

8.40

8.60

9.10

9.2

5. What to do if the textile is found to have a substandard pH?

The fabric or clothing has detected a pH failure. Generally, the pH of the fabric is readjusted by the principle of acid-base neutralization. Most of the unsatisfactory pH values are alkaline, and there are many types of acid agents that can be used for adjustment. The most common are glacial acetic acid and citric acid. Glacial acetic acid is volatile and has an irritating odor. Citric acid is more stable in adjusting pH, so It is generally recommended to use citric acid for adjustment, but pay attention to controlling the amount. Excessive amount will affect the feel and easily cause yellowing.

如面料测出pH值为9-10,可以调节柠檬酸水溶液的pH值为4-5,而后浸泡10分钟,晾干即可。 For example: If the pH value of the fabric is 9-10, you can adjust the pH value of the citric acid aqueous solution to 4-5, and then soak it for 10 minutes and dry it. Before sending it to the customer, we will send a formal inspection structure test to confirm compliance, reducing trade risks.

6. Control method of pH value:

Only by analyzing the cause of the unsatisfactory pH value and applying the right medicine, can we effectively reduce the rate of unacceptable pH value of textiles:

(1) Fabric companies should strengthen the quality awareness of relevant quality control personnel and the training of textile standards, and correctly understand the requirements of textile pH. Apparel processing enterprises also need to choose suitable noodles and accessories according to their own requirements and safety categories, and provide accurate requirements and standards to fabric suppliers. Attention from the source and quality control can avoid trade disputes caused by substandard pH.

(2) Relevant personnel of dyeing and finishing enterprises should actively learn about the safety of ecological textiles, be familiar with the requirements of standards, actively pay attention to the inherent quality of printing and dyeing products, optimize the production process, and actively improve the technical level.

(3) Inspection institutions or enterprise laboratories should perform inspections in strict accordance with inspection standards to ensure that the inspection data is fair and accurate, to avoid errors in inspection data caused by improper operations and other human factors, and to truly control product quality.

Next: None