1.What is the pH value?
The pH value is a measure of the acid-base strength of a solution. It is a simple way to express the concentration of hydrogen ions in a solution (pH=-lg[H+]). The value is generally between 1 and 14, with 7 being neutral. The more acidic the solution, the lower the value, and the more alkaline the higher the value.
2. The importance of pH testing
The surface of human skin is a weakly acidic environment with a pH value of 5.5 to 6.0. Acidic environment can inhibit the growth and reproduction of some pathogenic bacteria, prevent the invasion of external bacteria, and protect the skin from infection. pH value exceeds the standard too acid or alkali, the weak acidic environment of the human body will be destroyed, thus causing skin itching or allergy.
3. The principle of textile pH testing
After the textiles were extracted through distilled or deionized water, the pH of their extracts was determined using a pH meter with a glass electrode.
4.The cause of textile pH exceeded the standard
The influence of dyes in production: commonly used reactive dyes, shilin dyes, and sulfide dyes are produced under alkaline conditions. Even if the cloth can be washed and treated well, it will be affected by the pH value of the production water.
Effect of printing and dyeing process: Cotton, wool, silk, polyester, nylon, acrylic and other textiles after refining, dyeing, printing, and so on processing, fabric are residual alkali, acidification XuePin and additives, and the existence of different pH value, after washing, soaping, acid neutralization, drying process, such as post-processing, if insufficient high dosage of chemical fertilizer or washing post-processing, can make the pH levels of textiles, affect the performance of textiles.
The influence of fabrics: different thicknesses of fabrics affect the pH value of the cloth surface. Thin fabrics are easy to wash after dyeing, and the pH value of the cloth surface is low. Thick fabrics are relatively difficult to wash after dyeing, and the pH value of the cloth surface is relatively high.
The influence of operating errors of laboratory personnel: the different dry humidity of the test fabric, the different extraction temperature and the different extraction time will affect the determination results of the pH value of the cloth.
5. Improvement measures for pH unqualified textiles
Acid-base neutralization: acidic and alkali neutralization, alkaline and acid neutralization, generally used acid is acetic acid or citric acid, alkali is soda ash.
Dyeing and finishing process improvement: increase water washing, etc. Choose high-quality raw materials, dyes, etc., from the source to eliminate.
