Fluorescent whitening agent for powder substance like sodium sulfate, starch etc.
Sodium sulfate, sodium tripolyphosphate, sodium metasilicate, 4A zeolite, aluminum hydroxide, starch and other powder substances have different appearances due to different raw materials and origins, and some have very poor appearances. The purpose of whitening powdery substances is to improve the whiteness of their appearance and the whiteness of secondary powder processing products, and to improve the commodity value and performance.
1. Whitening principle
Spray the aqueous solution of fluorescent whitening agent and alcohol ether and phenol ether surfactants evenly on the surface of the powder. The surface of the powder will appear to be dyed with a layer of white dye to improve its whiteness. At the same time, the two auxiliary groups of hydroxyl and phenyl in alcohol ether and phenol ether surfactants have a synergistic effect on blue-violet fluorescence, making the powder appear whiter.
This method is suitable for whitening the appearance of powder materials such as sodium sulfate, sodium tripolyphosphate, sodium metasilicate, 4A zeolite, aluminum hydroxide, starch, etc. The whiteness of the powder can generally be increased by 5 to 10%. However, this whitening method is not suitable for powdery foods and colored powders.
2. Production technology and application examples
1. Production process
(1) Process flow:
Fluorescent whitening agent solution ↓
Powder material→surface spraying→drying→finished product
(2) Whitening liquid formula (mass fraction):
Fluorescent whitening agent 1%~5%
Alcohol ether surfactant 2%~5%
Phenolic ether surfactant 8%~15%
Alcohol 1%~5%
Deionized water 70%~88%
(3) Operation method: Add fluorescent whitening agent, phenol ether surfactant such as nonylphenol polyoxyethylene (10) ether and alcohol ether surfactant such as fatty alcohol polyoxyethylene in sequence to the deionized water at 60°C while stirring. Ethylene (9) ether, add alcohol such as ethanol after cooling down, stir thoroughly to make a uniform fluorescent whitening agent solution, set aside. Spray 2% to 3% (relative to the powder) fluorescent whitening agent solution evenly on the surface of the powder material under high-speed stirring, and then dry to obtain the finished whitening powder.
2. Application examples
Aluminum hydroxide powder whitening formula (mass fraction):
Optical brightener 31 # 2%
Nonylphenol polyoxyethylene (10) ether 10%
Fatty alcohol polyoxyethylene (9) ether 5%
Ethanol 3%
Distilled water 80%
Whitening process: Follow the above method to obtain the whitening powder of aluminum hydroxide.
