Milled soap is made using a soap base that is pressed under high pressure through a roller, during which the desired ingredients, such as flavors, colors, etc., are added. The most representative process is the triple-milling method. The benefit of this type of soap is that it removes excess moisture and air, making the soap beautiful, colorful, uniform, very hard, and smooth.
Prepare soap base
Soap base is the basic raw material for the manufacture of soap. The production process of soap base is scale and specialization, gradually forming a separate industry. So most factories that make soap do not produce soap base, they work directly with soap base suppliers and buy the required soap base. Soap bases can also come in a variety of varieties, based on the different oils/fats.
Batching
Mix all ingredients according to the recipe, add fragrances, colors and other additives (such as exfoliants or other active ingredients) to the existing soap base, and mix all ingredients thoroughly.
Purpose: To ensure that the various ingredients used are accurately executed according to the recipe, added accurately, and that is well mixed.
Refining and Grinding
The mixture goes into a heavy stainless steel drum for grinding and refining at least three times to remove excess air and water from the mixture and to ensure that all ingredients are thoroughly mixed. As a result, the soap is smoother and purer. Over-grinding in this process can dry out the soap, so it is critical to find a balance between moisture and quality.
Purpose: In addition to making the fragrance, colorants, and other additives more uniformly mixed, is more important to make the soap more finely and tightly organized and also to change the crystal phase of the soap, which facilitates the generation of the ß-phase making the transparent soap transparent and increasing the foam of the soap.
- When using a refiner to grind, use a 50 mesh/inch mesh plate in order to grind effectively.
- When grinding with a grinder, adjust the gap between the rollers to 0.2 to 0.4 mm.
- When grinding, pay attention to control the temperature of the soap material after grinding.
Extrusion
The grated soap goes through a conveyor belt into the soap press where it is pressed into a smooth cylinder and then squeezed to get the bar soap we want. The nose cone of the soap press heats the soap to make it more pliable and perfectly pressed.
The temperature of the gunnel of the bar press should be controlled at 50 to 60°C. Too high a temperature will make the surface of the soap bar blistered, and too low a temperature will produce wrinkles on the surface of the soap bar rough and not smooth. The temperature control to come out of the surface of the soap bar is smooth as a standard.
Vacuum room vacuum control at 0.06 to 0.08Mpa, too high will caused fragrance is pulled away by the vacuum, too low, there will be residual air caught in the soap bar, the formation of white core bubbles.
Also need to control the amount of cooling water in the screw jacket, to prevent the soap material in the screw slippage, the formation of soap bar core.
Pressing
Use a mold to press the soap into the shape you want, and print your logo on. We use a condenser press, which will leave a die line on the soap, but it is effective to recycle the excess soap into the soap extruder for reuse.
Before pressing, adjust the die so that the outer die can enter the die sleeve by about 2 mm, so that the soap is pressed without burrs, and the inner die should be adjusted so that the log is clear at the specified grammage.
In the pressing, need to constantly check whether the soap is sticky, if so, need to use a brush or rattan to clean the mold.
After printing the finished soap requires a smooth surface, clear handwriting, and no burrs.
Packaging
Pressed soap should be placed neatly and flatly in the drying tray which requires gaps or small holes under and around the soap to make it well ventilated, and put a clean pad of paper underneath to absorb water, to prevent the water vapor condensing on the bottom, causing the bottom of the soap to turn white. The drying time is measured as the time when the soap cools to room temperature.
Finally, package the product according to the specified packaging requirements.
A good package can communicate your brand story and also stop the soap from sweating.
