In a previous article, we discussed that some old linen may tear easily in laundry plants due to improper pH value in the long run. Then, how can we know the pH value of the washed linen? Today, we will share some common solutions with you.
Whether the pH value of the washed linen is proper or not is one of the indicators of washing quality. China has relative regulations on the pH value of the washed public textile.
In the current operation of the laundry plants, there are three ways to check whether the pH value is qualified.
The Final Rinse Water Testing Method (Indirect Method)
Laundry plants need neutralizing acid to adjust the textile’s pH value and neutralize the detergents and addictive residue in the linen.
● The indirect method uses the final rinse water to test its pH level so as to know the pH value of the linen.
This way is simple and costs little. It can be operated on-site in the laundry plants and has strong applicability in practical work. However, the results vary because the inspection object is not the linen itself.
The Acid-Alkali Test Solution Titration Testing Method for Linen (Direct Method)
● Drop the acid-base indicator test solution on the washed linen → observe its color → compare the color with the Colorimetric plate → estimate the pH value
This direct method has a short testing time and low costs. It can be done in the laundry plants and has a strong practical application. It requires the operators to know the laundry process and the relationship between the color change of the solution and the pH value. The testing result is closely related to the thickness of the textiles, water residue, the amount of the testing solution, and the operators’ experience. Different people may have different interpretations of the same result. Though the testing result may be a little different, its accuracy is higher than that of the indirect method.
pH Value Testing Method for Water Extract of Textiles
This method should be completed by the professional detection institution.
● Take a sample of textiles → Use the testing instrument → Test the pH value of the water extract of the linen
This method involves detailed research on all factors, so the testing result is highly accurate and stable. This designated method for issuing test reports by a third-party laboratory is credible and authoritative.
Conclusion
These three methods all have their own advantages. The direct method and indirect method apply to the daily routine check because they are quick and convenient. The water extract of the textiles testing method needs to be done by a professional detection institution. By combining the three methods, the laundry plants can control the pH value of the linen.
Post time: May-23-2025