pH is a very important quality indicator of textiles, and it is an enforceable indicator of GB18401-2010 "National Technical Specification for Basic Safety of Textiles". PH value is also a most common quality issue in the process of textile processing and production. People's attention, this article is with everyone to discuss how to control the pH of textiles.
1, the definition of pH:
The pH value is pH, and human skin is weakly acidic. Under this environmental condition, it can prevent the invasion of bacteria. Therefore, if the pH of the textile is between slightly acidic or neutral, it will help protect human health; on the contrary, the pH value of the textile High or low will destroy the skin's balance and resistance, causing skin allergies or induced infections that invade the bacteria.
2. Requirements for pH limit:
3, the source of abnormal pH:
Mainly for textiles in the dyeing and finishing process, the pH control is not enough, after the wet treatment is not enough acidity, or cleaning is not complete, easy to cause pH abnormal dyeing and finishing processes are mainly alkali reduction, polyester printing water washing, reactive printing water washing, cotton cloth Desizing, scouring and mercerizing.
4. Comparison of different methods for determining PH value of textiles:
(1) China Standard (GB/T 7573-2009)
Weigh 3 2 ± 0.05g samples, cut them into 5 × 5 mm pieces, placed in a flask containing 100ml distilled water, shake the flask to fully wet the sample, the flask was shaken on a shaker 2 Hours ± 5 min after the pH value of the water extract (without fabric) was directly measured with a pH meter at room temperature. Each sample was tested 3 times and the average of the second and third samples was taken as the final result. Accurate to 0.1.
(2) European Union Standard (EN 1413-1998)
Weigh 3 samples of 2±0.05g, cut them into small pieces of 5×5 mm, and put them in a flask containing 100ml of potassium chloride solution (0.1mol/L) or 100ml of distilled water. Shake the flask to make the sample full. After soaking, the flask was shaken on a shaker for 2 hours, and the PH value of the water extract (without fabric) was directly measured at room temperature using a pH meter. Each sample was tested 3 times and the second and third samples were taken. The average value of the sample results as the final result, accurate to 0.1.
(3) Japanese Standard (JIS L 1096-1999)
Weigh 5 ± 0.1g sample, cut it into small pieces of 1 × 1mm, after boiling in 50ml distilled water and hold for 2 minutes, put the sample in the flask, shake the flask to fully wet the sample, static at room temperature After 30 minutes, the sample was removed. When the temperature of the aqueous extract reached 25±2°C, the PH value of the aqueous extract was directly measured to the nearest 0.1.
(4) American Standards (AATCC 81-2001)
Weigh 10 ± 0.1g sample, cut it into small pieces, boil in 250ml distilled water and hold for 10 minutes, place the sample in the flask, shake the flask to fully wet the sample, continue boiling for 10 minutes, cooling After reaching room temperature, the sample was removed and the pH of the aqueous extract was directly measured with a pH meter to the nearest 0.01.
The pH value of cotton fabric water extract under different measurement standards:
Friendly reminder
From the above test standards and different test results of the same kind of sample, it can be seen that there must be standard requirements for testing.
Q: Why are the results different when the same sample is tested several times?
A: This may be due to errors in the test equipment, operation and environment, and errors in the test of distilled water. Therefore, it is recommended that the fabric manufacturer go to a regular inspection agency to perform the test.
5, textiles were detected pH unqualified how to deal with?
The pH of the fabric or garment was found to be unacceptable, and the pH of the fabric was generally adjusted by the principle of acid-base neutralization. Most of the unacceptable pH values ​​are alkaline, and there are many kinds of acid agents that can be used for regulation. The most common ones are glacial acetic acid and citric acid. The glacial acetic acid has a volatile and irritating odor, and citric acid regulates pH to be relatively stable. It is generally recommended to use citric acid to adjust it more appropriately, but it is necessary to pay attention to the amount of control. Excessive amount will affect the hand feeling, and it is easy to cause yellowing.
For example: If the fabric has a pH of 9-10, adjust the pH of the citric acid solution to 4-5, then soak for 10 minutes and let it dry. Sent to the customer before sending a regular inspection structure test to confirm the pass, reduce the trade risk.
6, pH value control method:
Only by analyzing the reasons for the unsatisfactory pH value, can we effectively reduce the unqualified rate of textile pH by following the remedy:
(1) The fabric enterprises shall strengthen the quality awareness of relevant quality control personnel and the study and training of textile standards, and correctly understand the requirements of textile pH. Apparel processing companies must also select suitable surfaces and accessories according to their own requirements and safety categories, and provide accurate requirements and standards to fabric suppliers. Pay attention to the source and carry out quality checks to avoid trade disputes caused by unqualified pH.
(2) Persons involved in dyeing and finishing enterprises shall actively learn eco-textile safety knowledge, be familiar with the requirements of the standard, take the initiative to attach importance to the intrinsic quality of the printing and dyeing products, optimize the production process, and actively improve the technical level.
(3) Inspection institutions or corporate laboratories shall conduct inspections strictly in accordance with the inspection standards, ensure that the inspection data are fair and accurate, and avoid the detection of data errors due to improper operation and other human factors, and truly put product quality at a high level.
For more content, please follow this site
Double Layer Forming Fabric,Machine Forming Fabric,Double Layer Forming Mesh,Mill Layer Forming Mesh
Dongguan Yexing Paper Felt&Wire Co.,LTD , https://www.yexingfelt.com