Melt Spinning Method

According to the addition process and method of far-infrared radiation material micro powder, there are four technological routes for the melt spinning of far-infrared fibers.

1. Full Granulation Method: During the polymerization process, far-infrared ceramic micro powder is added to make slices of far-infrared materials. The far-infrared micro powder is evenly mixed with the fiber-forming polymer, and the spinning stability is good. However, due to the introduction of the re-granulation process, the production cost is increased.
2. Masterbatch Method: The far-infrared ceramic micro powder is made into a high-concentration far-infrared masterbatch, which is then mixed with a certain amount of fiber-forming polymer for spinning. This method requires less equipment investment, has a lower production cost, and a relatively mature technological route.
3. Injection Method: In the spinning processing, a syringe is used to directly inject the far-infrared powder into the melt of the fiber-forming polymer to make far-infrared fibers. This method has a simple technical route, but it is difficult to evenly disperse the far-infrared powder in the fiber-forming polymer, and the equipment needs to be modified by adding a syringe.
4. Composite Spinning Method: Using the far-infrared masterbatch as the core and the polymer as the sheath, the skin-core type far-infrared fibers are made on a twin-screw composite spinning machine. This method has a high technical difficulty, good spinnability of the fibers, but complex equipment and high cost.

Blending Spinning Method

The blending spinning method is to add the far-infrared powder into the reaction system during the polymerization process of the polymer. The slices have the function of far-infrared emission from the very beginning. The advantage of this method is that the production is easy to operate and the process is simple.

Coating Method

The coating method is to prepare a coating solution by mixing a far-infrared absorbent, a dispersant, and an adhesive. Through methods such as spraying, impregnation, and roll coating, the coating solution is evenly applied to the fibers or fiber products, and then dried to obtain far-infrared fibers or products.

Function Testing of Far-infrared Fibers

1. Testing of Radiation Performance
   The far-infrared radiation performance is generally expressed by the specific emissivity (emissivity) as an index to evaluate the far-infrared performance of fabrics. It is the ratio of the radiation exitance M1(T, λ) of an object at temperature T and wavelength λ to the blackbody radiation exitance M2(T, λ) at the same temperature and wavelength. According to the Stefan-Boltzmann law, the specific emissivity is the same as the absorbance of the object to electromagnetic waves at the same temperature and wavelength. The specific emissivity is an important parameter reflecting the thermal radiation properties of an object, which is related to factors such as the structure, composition, surface characteristics of the substance, temperature, and the emission direction and wavelength (frequency) of electromagnetic waves.
2. Testing of Thermal Insulation Performance
   The testing methods for thermal insulation performance mainly include the thermal resistance CLO (Clo) value method, heat transfer coefficient method, temperature difference measurement method, stainless steel pot method, and thermal insulation measurement method under the irradiation of a heat source.
3. Human Body Test Method
   The human body test method includes three methods:

1. Blood Flow Velocity Measurement Method: Since far-infrared fabrics have the function of improving microcirculation and promoting blood circulation, the effect of accelerating the blood flow velocity of the human body can be tested by having people wear far-infrared fabrics.
2. Skin Temperature Measurement Method: Wristbands are made of ordinary fabrics and far-infrared fabrics respectively. They are put on the wrists of healthy people. At room temperature, the temperature of the skin surface is measured with a thermometer within a certain period of time, and the temperature difference is calculated.
3. Practical Statistics Method: Products such as cotton wadding are made of ordinary fibers and far-infrared fibers. A group of testers are asked to use them respectively. According to the feelings of the users, the thermal insulation performance of the two kinds of fabrics is statistically analyzed. This method can directly reflect the practical thermal insulation effect of far-infrared fibers in daily use, providing more practical data support for the evaluation of far-infrared fiber products. Moreover, as the requirements for health and comfort in daily life increase, the research and development of far-infrared fibers are constantly advancing, and more accurate and comprehensive test methods are expected to be developed to better evaluate their performance.