Sodium Alginate for Fibers

 

 

 

Alginic acid fibers are made by extracting alginic acid sodium and using wet spinning technology. They are a type of biodegradable regenerated cellulose fiber. Textile enterprises have developed algal fibers and produced some functional algal fiber products. These products not only meet people's demands for functional products but also effectively alleviate the shortage of natural fiber materials.

 

The application of algal fiber products can further play a role in protecting the environment. Each time a biodegradable fiber product is used, the use of an inedible biodegradable chemical fiber product is reduced, thereby reducing environmental damage and better protecting the earth on which we depend for survival.

 

 

1. Core principle: Wet spinning method

The production of alginate fibers mainly adopts the "wet spinning" process, which is based on the ionic exchange gel property of alginate.

Raw materials: Soluble alginate sodium.

Spinning aid: Dissolve alginate sodium in water to form a viscous and uniform spinning solution.

Coagulation: Calcium chloride solution.

Formation mechanism: When the alginate spinning solution is extruded through the spinneret and the fine stream enters the coagulation solution containing calcium ions, sodium ions will instantly exchange with calcium ions. The calcium ions act as cross-linking agents and quickly form a strong ionic bond network between the alginate molecules, thereby solidifying the soluble liquid stream into water-insoluble calcium alginate gel fibers.

 

2. Process Flow

A complete alginate fiber production line typically consists of the following steps:

Step 1: Preparation of the spinning solution

1) Dissolution process: Gradually add high-purity alginate particles into water, and under the condition of stirring and moderate heating, make them completely dissolve to form a uniform, transparent and bubble-free viscous solution.

2) Filtration and degassing: The solution undergoes fine filtration to remove impurities and receives vacuum degassing treatment to ensure process stability and fiber quality.

 

Step 2: Wet spinning process

3) Spinning process: The spinning solution is precisely delivered to the spinning net (a metal plate with numerous tiny holes) by a metering pump. The spinning solution is squeezed out through the holes of the spinning net, forming numerous extremely fine liquid streams.

4) Solidification process: The squeezed fluid immediately enters the calcium chloride solidification tank. Within a few seconds, an ion exchange reaction occurs on the surface and inside of the fluid, causing these fluids to solidify into alginate gel fibers.

5) After leaving the solidification solution, the fibers undergo moderate stretching to allow the molecular chains to align along the fiber axis direction, thereby increasing the strength and toughness of the fibers.

 

Step 3:

6.) Washing: The fibers that flow out of the coagulation solution carry a large amount of calcium ions and chloride ions. Therefore, they need to be washed multiple times with warm water until they reach a neutral state.

7.) Drying process: The washed fibers are dried in a drying oven to remove moisture, resulting in dry calcium alginate fibers.

8.) Wrapping: The dried fibers are wound onto the bobbin to form a fiber package.

 

Step 4:

9.) Ion Exchange: Depending on the final application requirements, the dried alginate fibers can be immersed in other salt solutions for ion exchange. For example, immersing them in a sodium chloride solution will cause them to partially reconvert into alginate sodium fibers (with strong water absorption properties). Immersing them in solutions containing silver, zinc, or other ions will result in the formation of alginate sodium fibers with antibacterial properties.

 

Item	Index
Appearance	Cream colored or lighter
Mesh	Particles or powders
Moisture, %	≦15.0
Ash, %	18-27
Viscosity, mPa·s	According to the need
Strength, g/c㎡	According to the need