In the industrial laundry, pre-treating hotel linens is important. It improves washing quality and efficiency. Different linen stains have various chemical components and adhesion characteristics. Direct mixed washing without sorting leads to poor cleaning performance. More seriously, it may trigger stain setting, linen yellowing, and fiber damage.
This article provides proper batch pre-treatment solutions for common linen stains in hotels. It helps laundry plants achieve efficient, low-energy consumption, and standardized production.
Blood Stains
● Pre-treatment timing
After linens are collected, process stains within 2 hours. When blood stains are heated or left for a long time, the hemoglobin proteins denature and coagulate. They bind tightly to fibers. This makes the stains difficult to remove.
● Steps
- Cold-water soaking
Soak linens in the 15-20℃ cold water for 30 minutes to loosen blood stains. Hot water leads to protein solidification. Protein penetrates into fibers, which cannot be removed.
- Enzyme treatment
Add 500 g of neutral protease detergent per 50 kg of linens. Slightly stir or turn over linens to ensure full contact between enzyme liquor and blood stains. Allow linens to dwell for 20 minutes. In this period, keep the water temperature below 30℃. Protease enzymes become inactive above 40℃.
- Main wash
After finishing the above steps, separate rinsing is not required. Directly follow the main wash process (alkaline main wash and bleaching).
● Cautions
Avoid using chlorine bleach (such as sodium hypochlorite) to pre-treat blood stains. Due to chlorine, the iron in hemoglobin is oxidized to form black ferric sulfides. They trigger permanent stain setting. For old or stubborn blood stains, apply concentrated protease detergent first. Cover wet towels and dwell linens for 10 minutes. Then soak linens in the solution.
Grease Stains
● Pre-treatment chemicals
Industrial-grade nonionic surfactants (such as fatty alcohol ethoxylates ) or special alkaline degreasers can effectively reduce the oil-water surface tension. They emulsify grease into small particles in water.
● Steps
- Dry linen spray (target heavy grease stains)
Keep linens dry. Dilute the degreaser at a ratio of 1:10. Then evenly spray it onto the heavily soiled areas. Use the soaking method for light to moderate grease stains. Dilute the degreaser at a ratio of 1:50 in 30℃ water. Soak linens for 20 minutes.
- Synergistic treatment
Add soda ash to the soak liquor. The dosage is 300 g of soda ash per 50 kg of linens. Soda ash can raise the pH of wash liquor to 10-11. It promotes grease saponification. This significantly enhances grease removal performance.
- Main wash
The pre-treated linens directly enter the main wash cycle. Use chlorine bleach (effective chlorine concentration 80-100ppm) to remove the residual pigment on cotton linens.
● Cautions
For cotton-polyester blends, avoid using alkaline degreasers with a pH above 12. This damages the polyester fiber surface. Linens may become stiff and lose their strength. Use neutral or mildly alkaline emulsifiers in the pH 8-9.
Tea/Coffee Stains
● Pre-treatment principle
Under neutral conditions, tannic acid and polyphenols in tea and coffee stains are difficult to remove. But they can be decomposed in an acidic environment. Oxidizing bleaches also damage the conjugated structures in pigments.
● Steps
- Soak in acid solution
Citric acid (5 g/L) or oxalic acid (3 g/L) solution can be used. Soak the tea- or coffee-stained linens for 20 minutes in the solution. In this period, turn over linens 1-2 times. Oxalic acid is poisonous. Wear rubber gloves during the operation. Use citric acid which is safe and odor-free.
- Rinse with clean water
Rinse linens with clean water for 1-2 minutes. This removes pigment and acid residues.
- Regular wash + oxygen bleach
For stubborn pigments in white linens, add oxygen bleach in the main wash liquor (1 kg of sodium percarbonate for each 50 kg of linens). Wash them at 40℃ for 30 minutes. Sodium percarbonate releases active oxygen. This helps decompose pigment resides. With chlorine bleach (only for white cotton linens), this step can achieve whitening results.
● Cautions
Avoid using oxalic acid and chlorine bleach for high-end linens (mercerized cotton and silk). Replace it with gentle oxygen bleach solutions.
Sweat Stains
● Stain characteristics
Sweat stains contain 98% water. Solid components include sodium chloride, urea, lactic acid, fatty acids, and small amounts of protein. Sweat stains accumulating for a long time lead to linen yellowing and odors. Salt crystals also damage fabric fibers.
● Steps
- Soak in warm water
Put the linens in water for 30 minutes. Keep the temperature below 50°C. This helps avoid protein damage. Add 400 g of neutral powdered detergent (or 800 ml of neutral liquid detergent) and 200 g of water softener (such as EDTA-2Na or sodium citrate) for each 50 kg of linens.
- Mechanical agitation
Keep the soaking solution circulating or turn over manually for 15 minutes. This helps salt dissolve completely. Grease and little protein can be emulsified and suspended.
- Complete rinse
After the pre-treatment, rinse with clean water at least twice (Or directly enter the main wash cycle after drainage. Spin linens before the main wash). Prevent salt, and calcium and magnesium ion residues. Otherwise, this leads to a rough fabric feel, reduced water absorbency, and linen yellowing.
● Cautions
For linens with a large amount of sweat stains (such as towels in gyms), regularly use acid solution (citric acid solution with pH 4-5) to neutralize residual alkaline substances in regular wash cycles. This prevents fiber weakening.
Conclusion
The above solutions provide batch pre-treatment methods for common hotel linen stains (protein, grease, pigment, and mixed types). During industrial washing, laundry plants should properly use enzyme-based detergent, emulsifiers, acid/alkali modifiers, and oxygen bleach. This ensures processing efficiency and improves stain removal performance. Pay attention to conducting small scale tests before any pre-treatment. Confirm that linens are not damaged before batch processing. Laundry plants should continue optimizing wash parameters in practice. This helps promote a greener and more efficient development of the laundry industry.
Q&A
Q1: Does a washer support a cycle for this special stain?
A1: A Kingstar washer supports various special cycles. The equipment can store up to 50 wash cycles. They meet laundry needs for different linens.
Q2: Why is the industrial washer draining slowly?
A2: Check and clean the drainage pipeline. Foreign objects, such as hair and grease buildup, easily trigger blockages.
Q3: If linens with a specific type of stain are not enough for one machine, how can a laundry plant improve the processing efficiency?
A3: Remove stains first. Then wash them with other linens. A laundry plant can use a 40 kg/60 kg industrial washer.
Post time: Jul-03-2026