Introduction
Soap, in its diverse forms and compositions, has an evolving market worldwide. Laundry soap, toilet soap, medicated soaps, translucent soaps, high-lather soaps… the varieties are endless. Underlying all these varieties are soap noodles - the basic building blocks of soap manufacturing.
Driven by growing consumer awareness and the consequently growing market for soaps of diverse kinds, the soap noodles market is also booming. Urbanisation and increasing disposable incomes in Asia-Pacific, Latin America, and other emerging markets are contributing to strong growth in soap production. Not to mention the technological advancements in the industry that have been able to cater to evolving consumer preferences.
Vegetable oils and animal fats are important raw materials in the saponification process, an integral step in the soap noodles manufacturing process. This process yields not only soap noodles which can be sold to soap manufacturers and other industries but also glycerin, a valuable resource in skincare, pharmaceutical, food, paint, and other applications.
Soap noodles are, therefore, a part of the downstream value chain of the plant-based oils industry. For businesses already producing vegetable oils (or even animal fats), setting up a soap noodles plant is a great way to produce value-added products.
Whether you want to enter the soap noodles manufacturing industry or vertically integrate multiple processes in the edible oils value chain, investing in a soap noodles plant can be a lucrative option. Of course, first, you must understand the soap noodles manufacturing process. So that's exactly what we're going to do here. Let's dive right in.
What are soap noodles?
The answer lies in their name. Put simply, soap noodles are pre-formed, ready-to-use, dried blocks of soap material.
Typically, they are the sodium salts of fatty acids, made from vegetable oils or animal fats reacted with caustic soda. Given their ease of handling and their versatility, they serve as the foundation for making soaps, laundry detergent, cleaning agents, and many other such products, especially in large-scale manufacturing. Soap noodles also have applications in textile spinning, lubricant manufacturing, and even the de-inking of recycled paper.
Types of soap noodles
Given their diverse applications, naturally, there is not one type of soap noodle.
There are snow white soap noodles - high purity, high clarity with minimal odour and colour, ideal for premium and cosmetic-grade soaps.
There are multipurpose soap noodles - a versatile variety made for household and industrial cleaning applications like body washes, liquid soaps, and the like.
There are also laundry soap noodles, formulated to remove tough stains, made particularly for laundry detergents.
Understanding the saponification process
Saponification is the chemical reaction central to the soap noodle manufacturing process.
fat + 3lye --> soap + glycerol
It is the exothermic reaction that occurs when the triglycerides in the fat or oil combine with a strong alkali (typically sodium hydroxide, also called caustic lye. To make softer soaps, potassium hydroxide may also be used).
The alkali breaks the ester bond to produce soap (a fatty acid salt) and glycerin (also called glycerol). This transformation solidifies the soap and gives it its cleansing abilities. It also leads to the production of glycerin, a moisturizing by-product, which may either be retained in the soap as a softening agent, or isolated and supplied to other industries where it serves important applications.
The saponification reaction:
The quantity of lye used varies based on the oil in question. Each oil has a saponification value, a measure of the amount of lye required to convert all the triglycerides into soap. Too much lye can make the resulting soap noodles too harsh, while too little lye may result in the produced soap not fully solidifying.
Raw materials in the soap noodles manufacturing process
As we've seen from the saponification reaction, the main raw materials needed in the soap noodles manufacturing process are a strong alkali and appropriate vegetable- or animal-derived fats.
The main fat/oil used depends very much on the region where the soap noodles are being produced and what is available there. Globally, however, the most commonly used triglycerides are coconut oil, palm oil, palm kernel oil, and animal fat or other blends.
Each of these fats produces soap of differing odour, lathering, and hardness, so soap noodle plant operators also take care to use a single fat or a blend (in measured ratios), as appropriate, to produce soap noodles of the desired characteristics. The cost of raw materials also determines which ones are used.
The industrial soap noodle manufacturing process
While the saponification process is central to the entire soap noodle manufacturing process, there are many steps - before and after - which are necessary to produce high-quality soap noodles with the desired characteristics in an industrial setting.
Step 1. Saponification.
The cleaned and measured reactants - Like, coconut oil or other fat blend along with sodium hydroxide - are mixed in a saponification reactor where the reaction condition is maintained after the specific reaction time, the product mixture soap and glycerin are produced.
Soap noodle plants may rely on either batch processes or continuous processes, the latter of which involves the continuous addition of fat to the reactor and the continuous removal of the final products from it.
Depending on the desired soap noodle quality, soap noodle plants also choose between the cold process, hot process, and fully-boiled process for soap noodle manufacturing. These processes vary in terms of reaction temperature, process steps, and processing time.
Step 2. Glycerin removal.
Glycerin is a highly valuable resource, so at many soap noodle plants, manufacturers isolate and remove the glycerin from the soap+glycerin mixture to make the high quality soap noodle as well the glycerin.
Step 3. Soap purification or neutralisation.
Even after the saponification reaction, some of the alkali i.e. sodium hydroxide may remain unreacted. So a weak acid like citric acid is used to neutralize it. The neutralisation process not only removes residual impurities but also adjusts the pH to ensure the soap noodles meet quality standards.
Step 4. Drying and milling.
After neutralisation, the soap material is dried and milled to give it the texture and consistency needed for further processing. This not only eliminates excess moisture but also makes the soap noodles easy to use.
Step 5. Shaping and cutting.
After drying, the soap material is extruded to give it a noodle shape. The soap noodles are further cut into uniform pieces that can be easily handled and transported to soap manufacturers.
Soap manufacturers add colours, fragrances, preservatives, and other additives and shape the soap material into bars to distinguish their soap from others.
That's it - a simple overview of the soap noodles manufacturing process. Our experts are happy to discuss more detailed soap noodle plant plans with you and explore how we can work together. Get in touch today.
