Lin Chunzhao's Interpretation: Six Key Factors Affecting Linen Washing Quality
Release Time:
2019-04-08 15:13
Source:
The quality of linen washing is related to the following factors.
Factors of washing Including: water quality, raw materials, time, temperature, water level, load, pH value, concentration, mechanical force, and other factors. Today, I will share some viewpoints on these.
1. What is the impact of hard water on washing?
Hard water contains calcium and magnesium impurities and trivalent iron. Calcium and magnesium impurities react with soap (sodium fatty acid) to form calcium and magnesium soap, also called soap scum. It is a kind of dirt itself, sticky and insoluble in water, difficult to remove once it contacts clothes, and over time it stains the fabric, causing it to darken, yellow, and become brittle. The harder the water, the more detergent is consumed, so the detergent dosage must be increased. Generally, the detergent amount should be increased by one-third.
Effects of hard water on washing:
1. Increases detergent consumption.
2. Affects the function of surfactants.
3. Deposits on linen, causing it to gray, darken, and become brittle.
Effects of iron on washing:
1. Affects the performance of bleach.
2. Causes linen to yellow.
Poor water quality not only damages linen but also causes equipment scaling. Therefore, soft water can solve these problems and save detergent usage.
2. Washing temperature
Main components of color bleach powder
However, washing temperature should not be blindly increased. The heat resistance of fabric fibers must be considered, the performance of raw materials, the heat resistance of pigments in colored fabrics, and the heat resistance conditions of washing equipment.
Choose the upper limit temperature for washing based on the above conditions to maximize cleaning while avoiding unnecessary damage.
For normal washing, every 10℃ increase in temperature doubles the washing reaction speed, so the performance of washing materials and whether excessive temperature damages fibers must be considered. For example, when using bleach or chlorine bleach powder, the temperature must not exceed the conventional usage temperature.
Bleach (sodium hypochlorite) temperature must not exceed 60℃, and chlorine bleach powder temperature must not exceed 65℃, this is determined by the amount of organic bleach contained in the oxygen bleach.
3. Washing liquid concentration
For general clothes (light dirt), the washing liquid concentration is generally controlled at about 0.2-0.5%. For dirtier tablecloths, napkins (mouth cloths), kitchen uniforms, etc., the concentration can reach 1%. For washing shirts and white work clothes with light dirt, the concentration is about 0.3%, and for heavy dirt, about 0.5%. For hospital doctors' white coats, the concentration for light dirt can be about 0.5%, and for heavy dirt, about 0.6-0.8%.
Note: Too much detergent and overly strong concentration often cause dirt that has been washed off to redeposit on the surface of clothes or even accumulate in the fabric fibers' capillaries, making clothes gray or blackened, giving the impression that clothes are not clean. This phenomenon is usually called "color aggregation."
4. Washing time
Some believe that the longer the washing time, the better the stain removal and the cleaner the clothes. This view is incorrect; good results can only be achieved within a normal washing time.
The main washing time for general clothes is 10-15 minutes, and for dirtier tablecloths, napkins (mouth cloths), kitchen uniforms, the main washing time is controlled within 20-30 minutes. Usually, the entire washing cycle is controlled within one hour, with sheets, bedding, work clothes, towels, etc., taking about 55 minutes.
If washing time is too long, the mechanical action of the washing machine increases, which increases fiber wear and shortens fabric lifespan. Also, as mentioned earlier, some dirt may return into the fabric fibers' capillaries, causing artificial dirt redeposition and reducing washing effectiveness.
5. The role of water level in the main wash
The water level during the main wash is also critical and directly affects the washing effect, so different water levels should be used during the main wash depending on the fabric type, variety, and degree of dirt.
Most main washes use a low water level, because low water level water has the strongest impact force, which helps water-soluble dirt detach from fabrics and produces optimal friction. Although high water level provides sufficient water, the mechanical force generated by the washing machine drum rotation is reduced by the excess water, so sufficient water impact force cannot be formed. This reduces friction between fabrics and lowers washing effectiveness, sometimes causing clothes not to be cleaned properly. Therefore, high water level is not suitable for the main wash.
Additionally, the water level also affects the amount and concentration of washing materials added, increasing washing costs.
6. The impact of load on washing
It is also necessary to understand the relationship between the washing machine's load and washing effect during washing. Many laundry workers generally believe that as long as more fabrics to be washed are loaded into the washing machine, with a loading rate exceeding 90% or even overloaded, extending the washing time and adding more detergent, or even raising the temperature, will achieve the same decontamination effect and clean the laundry well. They do not consider that overloading affects mechanical force and causes mechanical overload, which may damage the washing machine. This not only wastes time and results in unclean washing but also wastes materials and causes repeated re-washing. The dirt on the laundry is not cleaned, which is a common problem in the laundry industry.
The correct loading requirement is 75%–80% of the washing machine's capacity as the standard, providing enough space for washing to generate effective mechanical force, impact force, and friction effect to achieve decontamination.
☆Author Introduction
Lin Chunzhao
* Senior Laundry Technician, Senior Examiner for National Vocational Skill Appraisal
* Engaged in the laundry industry for more than 50 years
* Served as Deputy Secretary-General when the Guangdong Laundry and Dyeing Association was established in 2005
The above content is only the author's personal opinion, welcome to communicate
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