1. Application of carbon black in antistatic fiber
Antistatic fiber refers to the fiber whose resistivity is less than 1010Ω·com under the standard state or the fiber whose electrostatic charge dissipation half-life is less than 60s, which can reduce the disappearance of electrostatic potential during textile processing and the use of its products. It has temporary and Permanent two antistatic fibers. The reason for static electricity is that the macromolecules are bound by covalent bonds, cannot ionize, and cannot transfer electrons. In addition, the macromolecular groups have small polarity, high hydrophobicity, and the charge is not easy to escape. The resistivity is as high as 1012-1013Ω·com , so synthetic fibers are prone to static electricity. Antistatic fiber has the advantages of small volume resistivity, easy to eliminate static electricity, good processing and safety performance, and its physical and chemical properties are basically not affected. The main varieties are antistatic fibers such as viscose, polyester, nylon and acrylic.
Antistatic fibers are mainly used in departments and industries with high antistatic requirements, such as manufacturing dustproof clothing, sterile, antistatic work clothes, explosion-proof dust removal products, filter felts, dust filter bags, anti-electromagnetic radiation materials, carpets, mine conveyor belts, Automotive interior decoration products, etc. There are many ways to manufacture antistatic fibers in the future. Among them, the long-term effective and economical method of antistatic is to use melt spinning method to add carbon black to chemical fibers to prepare antistatic fibers. The manufacturing method is as follows:
(1) blending method
During polymerization or spinning, the antistatic fiber can be obtained by mixing the polymer or its chips with carbon black powder and spinning. In order to improve the dispersion performance of carbon black, the surface of carbon black is generally treated with a coupling agent. Commonly used coupling agents are siloxanes, aminosiloxanes, and ethylene glycol.
The antistatic fiber prepared by this method has a relatively durable antistatic effect, because the carbon black particles exist at a higher density in the fiber cross section. Arranged along the axial direction of the fiber, a low-resistance path for transporting or conducting charges is formed inside the fiber. Both the inside and the outer surface of the fiber can quickly dissipate the charge, and the antistatic effect is significantly improved.
(2) Adding carbon black antistatic masterbatch spinning method
Surface treatment of carbon black with ethylene glycol or other coupling agents, the treated carbon black powder and polymer carrier, such as polyester chips, are extruded and granulated through a twin-screw extruder to obtain carbon black resistant Static masterbatch. After mixing the masterbatch and spinning chip evenly, the antistatic fiber can be prepared by melt spinning. Using this method can ensure that the carbon black has better dispersion properties and better electrical conductivity.
(3) Composite spinning method
This is a commonly used method for making antistatic fibers at present, such as making sea-island or core-sheath composite fibers, in which the island phase or core is a polymer component containing an antistatic agent, and the basic polymerization of the sea phase or sheath The antistatic component has a protective effect to maintain long-term antistatic performance without affecting the original style and mechanical properties of the fiber.
2. Application of carbon black in conductive fibers
Conductive fiber refers to the fiber whose resistivity is less than 107 Ω cm under standard conditions. High specific resistance conductive fiber can be used in anti-static clothing, gloves, carpets, curtains, interior decoration of vehicles, computer room studios, hospitals, etc. to shield static electricity. places; medium specific resistance conductive fibers are mainly used in petroleum, petrochemical, coal, plastic, rubber and other industries; low specific resistance conductive fibers are mainly used in radio, television, electronic instruments, precision equipment and other fields to prevent electromagnetic wave interference.
Conductive fibers are often made by compounding non-conductive organic fibers and conductive components. This method takes advantage of the easy formability and softness of polymers. Therefore, not only can the degree of electrical conductivity of fibers be adjusted through different compounding methods and degrees of compounding, but also the degree of molecular orientation within the polymer can be used to adjust its electrical conductivity. of anisotropy.
(1) Basic preparation method of carbon black conductive fiber IDE
1. Surface coating method
Conductive fibers can be obtained by coating carbon black powder and binder on the surface of the fiber and curing it. The fibers prepared by this method have good electrical conductivity, but poor dyeability and durability, low yield and high cost.
2. Composite spinning method
The carbon black is uniformly dispersed in the matrix polymer by means of kneading or mixing to form a conductive component, which is then composite-spun with a non-conductive component (main polymer) to obtain a composite conductive fiber. The matrix polymer of the conductive component includes polyamide, polyester, polyethylene, polyethylene glycol, etc. The non-conductive component can be the same polymer, or two or more polymers can be selected.
(2) Typical conductive fiber process
Carbon black composite conductive fiber with carbon black (acetylene black, channel black, furnace black, thermal cracking carbon black, soft carbon black, etc.) The largest variety. The carbon black it uses requires low resistivity and can be well dispersed in the matrix polymer (polyamide, polyethylene, polyoxyethylene, fatty acid polyester, etc.). The content of carbon black in the conductive component depends on the matrix polymer and the type of carbon black. When the content of carbon black is generally between 3% and 40%, it can ensure smooth spinning and the mechanical properties of the fiber will not be greatly reduced. Non-conductive components can use polyethylene terephthalate
Alcohol ester, polyamide, polyurethane, polyacrylonitrile and other fiber-forming polymers. Due to the addition of carbon black, the appearance of the conductive fiber is black. In order to reduce the restriction of the black appearance on the application range, carbon black composite conductive fibers with different composite forms and cross-sectional shapes can be designed and manufactured.
3. Application of carbon black in fiber coloring
The application of carbon black as a dye in fiber can be directly added to carbon black during fiber processing for dyeing. But at present, the most widely used dyeing method is masterbatch coloring. It is a kind of chemical fiber dope coloring. After the dye is made into a masterbatch, it is mixed with a colorless resin in a certain proportion and spun into a colored fiber. Due to the use of masterbatch products, there is no dust flying, and it can improve the working environment. Compared with other methods, it has the advantages of good color fastness, uniform tone, bright color, complete color spectrum, low processing cost and even dyeing after dyeing. Therefore, In recent years, the domestic production of carbon black masterbatch has developed very rapidly.
Among the various and colorful masterbatches, black masterbatches are particularly popular, and carbon black is widely used in the coloring of synthetic fibers and plastics. In the black masterbatch, a high concentration of carbon black coloring agent is usually added, and this black masterbatch can be combined with plain particles to spin ideal black or gray filaments. The dyeing of fibers is usually carried out at a temperature of 250-300 ° C. Since organic dyes are unstable at this temperature, it is most suitable to use carbon black. For some needs, it has high light fastness, color fastness and heat fastness. And UV-resistant stability products, currently mainly adopt the method of mixing the color masterbatch in the slices for spinning or injecting the dye before feeding the screw extruder. Compared with other dyes, carbon black has good heat resistance, and the pigment particles on the fiber section are well distributed, and the dyeing is uniform.
Masterbatch coloring is widely used because of its better economic benefits and flexibility. Masterbatch colored polyester and polypropylene fiber black silk have also been greatly developed. Carbon black occupies an important position in the coloring of polyester melt masterbatches. Black accounts for 70% of melt-colored polyester long and short fibers. In addition, carbon black is also widely used in the coloring of polyamide fibers.
In addition to the application of carbon black in conventional dyeing of fibers, it has important applications in the development of differentiated fibers and the treatment of recycled materials.