How to use fluorescent whitening agents in soap
In the production of soap, laundry soap and toilet soap are two extremely important varieties. Fluorescent whitening agents are also widely used in laundry soap and toilet soap to improve the appearance of the soap body, making the white soap body whiter and the light-colored soap body more Brilliant, while whitening the fabric being washed. Other varieties such as medicated soap, antibacterial soap, deodorant soap, etc. are produced on the basis of these two varieties.
1. Production of laundry soap
Laundry soap can be divided into ordinary laundry soap, whitening laundry soap, soap powder, etc. The production process of laundry soap includes the following processes:
Excipients such as caustic soda, spices, fluorescent whitening agents, colorants, etc.
Grease Refining Saponification Soap Base Blending Shaping Cutting Drying Printing Packaging Soap Head According to different production equipment, the production methods of laundry soap can be divided into cold barrel method, cold plate car method, vacuum drying and cooling method, roller cooling extrusion method and pressing method. Among them, the former three methods are the most widely used.
The cold bucket method is one of the oldest production methods. It mixes the soap base and the required fluorescent whitening agent and other auxiliary materials evenly, then puts it directly into a rectangular soap bucket with an opening on the top that can be removed on all sides, and allows it to cool naturally and form. , then cut into pieces, dried, printed, and packaged.
The cold plate car method is currently used by most soap factories in my country. It adds soap base to a blending pot, then adds caustic soda, spices, colorants, and fluorescent whitening agents, and blends at 70~80°C for 15~20 minutes. , then press it into the cold plate car, condense with cold water for 45~60 minutes, take out the large soap, then cut into pieces, dry, print, and package.
The vacuum drying and cooling method is currently the most advanced laundry soap forming method in the world, and is also used by many manufacturers in my country. This method first adds soap base and water to the blender, then adds a certain concentration of caustic soda with a modulus of 2.44 to ensure product hardness; then adds 0.1% ~ 0.2% titanium dioxide, and finally adds 0. 3% ~ 0. 5% flavor, 0. 03% ~ 0. 5% optical brightener, appropriate amount of calcium soap dispersant and colorant, etc. After the slurry is evenly mixed, it is filtered and then pumped into a vacuum cooler to cool, solidify and form, then cut into pieces, dried, printed and packaged.
2. Production of soap
The composition of toilet soap and laundry soap are basically the same, but the quality requirements for the soap base are stricter. Generally, the water content is 10%~15%, and more additives need to be added. The production process of soap includes the following processes:
Spices, fluorescent whitening agents, colorants and other auxiliary materials
Grease Refining Saponification Soap Base Drying Blending Grinding Vacuum Pressing Printing Cooling Packaging Judging from the production processes of the above two soaps, the timing of adding fluorescent whitening agents is relatively fixed, and they are all added during the blending process. Among the above processes, blending is the most critical operation. The purpose of blending is to put the soap base into the blending tank, add fillers, builders, spices, fluorescent whitening agents and other auxiliary materials, and then stir to blend evenly, and To achieve the quality indicators of soap products such as hardness, fatty acid content, appearance, smell, and detergency. This operation is usually performed in the blender.
For soap, after blending, it must be ground with a three-roller or five-roller grinder, usually twice, to make the fillers, builders, spices, optical brighteners and other auxiliary materials and soap base more evenly mixed.
Due to the mild conditions of the blending process, any optical brightener used in laundry products can be selected as needed. However, for whitening laundry soap, the fluorescent whitening agent plays a more important role in whitening the fabric than the soap, so a larger amount of fluorescent whitening agent needs to be added during the blending. Choose a variety that has a higher blending amount in soap, a greater solubility in water, and will not cause the fabric to turn yellow or green after repeated washing. Commonly used varieties include C.I. optical brightener 31, 71, and 351. At this time, the optical brightener can be dissolved in a certain amount of water and then mixed with other soap-making components.
If spray drying is used to make soap powder, additives such as auxiliaries, optical brighteners, and colorants need to be mixed into the hot soap base before drying. After the additives and soap base are mixed evenly, they are sent to a storage tank for aging, and then sent to the spray tower through a high-pressure pump for spray drying to obtain soap powder. In this case, the optical brightener chosen should be stable at spray drying temperatures.
3. Application examples
The following are several soap recipes. According to this recipe, different products can be produced according to the above production process.
Application Example 1:
Ordinary laundry soap. formula:
Soap base 100 parts
Sodium silicate 10 parts
Titanium dioxide 0.1 part
Flavor 0.4 parts
Optical brightener 31 # 0.1 part
Application example 2:
Whitening laundry soap. formula:
Soap base 100 parts
Sodium silicate 10 parts
Flavor 0.4 parts
Optical brightener CBS 0. 08 parts
Application Example 3:
Ordinary soap. Recipe:
Soap base (80% fatty acid) 100 parts
BHT (butylated hydroxytoluene) 0.1 part
Fluorescent whitening agent 0.015 parts
Titanium dioxide 0.1 part
EDTA 2Na (disodium ethylenediaminetetraacetate) 0.1 part
1.5 parts of essence
Application example 4:
Beauty soap. Recipe:
Soap granules 100 servings
EDTA 2Na (disodium ethylenediaminetetraacetate) 0.1 part
Fluorescent whitening agent 0.2 parts
Hydroxymethylated milk 2 servings
Titanium dioxide 0.1 part
BHT (butylated hydroxytoluene) 0.1 part
Flavor 1.2 parts
1 part emulsified silicone oil
Application example 5:
Whitening soap. Recipe:
Soap granules 100 servings
EDTA 2Na (disodium ethylenediaminetetraacetate) 0.1 part
Fluorescent whitening agent 0.01 part
Arbutin (natural whitening agent) 0.5 parts
Titanium dioxide 0.15 parts
BHT (butylated hydroxytoluene) 0.1 part
Essence 1.2 parts
