In order to make nonwoven materials have good performance, in addition to dyeing, printing and other processing, various functional finishing such as aromatic, oil and water repellent, antifouling, flame retardant and antibacterial are often carried out according to actual needs. In the finishing process, as people’s understanding of the application of microcapsule technology in the nonwoven field continues to deepen, microcapsules will be increasingly used in the finishing process of nonwoven materials. Microcapsule technology has begun to be used in the finishing process. The nonwoven industry has shown huge development potential.
Heat storage and temperature regulating microcapsules
Improve the temperature control function of nonwoven fabrics
Triangle Company of the United States announced that it has synthesized heat storage and temperature-regulating microcapsules with a diameter of 15 μm to 40 μm and has the function of absorbing and releasing heat energy, and used them to clean the surface of the fabric to obtain a non-woven fabric with temperature regulation function. Triangle Company adds heat storage and temperature-regulating microcapsules with a mass fraction of about 7% during the wet spinning process of polyacrylonitrile, and extrudes it through a spinneret to form fibers. The microcapsules can be directly embedded inside the fibers, making the inside of the capsules Phase change substances are more stable in fabrics.
Heat storage and temperature-regulating microcapsules are made by coating phase change materials (PCM) in a specific temperature range with certain polymer materials to form normally stable microcapsule solid particles with a diameter of approximately 1 to 30 μm. The core material selected for heat storage and temperature-regulating microcapsules is mainly paraffin alkanes, and the wall material requires good film-forming properties and chemical stability to prevent the core material from penetrating under the action of external forces. The post-finishing process using heat-storage and temperature-adjusting microcapsules is: preparing heat-storage and temperature-adjusting microcapsules → finishing the nonwoven fabric by dipping method (two dipping and two rolling) → pre-baking → baking, and then finishing the heat-storage and temperature-adjusting microcapsules. Thermal nonwovens can be used as cushion materials, curtain fabrics, wall coverings, etc.
Figger, executive vice president of Triangle Company, said that the application of microcapsule technology in nonwovens mainly utilizes three properties of microcapsules. The first is isolation performance. After some photosensitive, heat-sensitive or biological materials are embedded as core materials, when they need to be released, the materials can be released by destroying the wall materials using means such as light, heat, pressure and biological effects. ; The second is the sustained release performance, the core material gradually penetrates and evaporates through the capsule wall, extending the action time; the third is the foaming performance, when the microcapsule is at a certain temperature, the core material solvent vaporizes, and the wall material is expanded to form a bubble. The purpose of foaming can be achieved. This performance is mainly used for foam printing. The simultaneous application of these three technologies is an important factor in achieving temperature regulation of nonwoven fabrics.
Disinfection and finishing microcapsules
Protect workers from chemicals
German Sandler has launched a disinfection finishing microcapsule that can be used for protective clothing.
Klaus, senior sales manager of Sandler Asia, pointed out that workers in some departments may be exposed to various toxic and harmful chemicals, and there is an urgent need for protective clothing to protect workers from chemicals. In the past, there were two finishing methods with different mechanisms in the production of this type of protective clothing. One was to use activated carbon to treat fabrics, but the desorption problem after activated carbon adsorbs chemicals has not been well solved; the second was to use chloramide to treat fabrics, which has the disadvantage of certain Hypochlorite is easily released under humidity and can cause skin inflammation. The above shortcomings can be overcome by using sterilization and finishing microcapsules in the post-finishing process of non-woven fabrics.
“The reactive chemical disinfectant is wrapped in a semi-permeable polymer wall material to form microcapsules. The reactive chemical disinfectant cannot penetrate and pass through the wall material film. If toxic chemicals are selectively allowed to pass through the wall material Entering the microcapsule, the reactive chemical disinfectant reacts with the toxic chemical agent inside the microcapsule to achieve the purpose of disinfection. The reactive chemical disinfectant in the microcapsule will not cause harmful irritation to human skin, and will also cause disinfection. It can be fixed in non-woven fabrics through resin finishing and other methods, and will not be decomposed by heat, moisture and light. The application of chemical disinfectant microcapsules in protective clothing is a new research direction for chemical protective clothing,” Klaus explained.
In addition, the disinfection and finishing microcapsules can also be used simultaneously with ultraviolet absorber microcapsules. Ultraviolet absorber microcapsules can avoid molecular decomposition caused by long-term strong ultraviolet radiation and improve ultraviolet protection performance. The anti-UV microcapsule finishing process is to prepare anti-UV microcapsules, apply them evenly on the non-woven fabric, use a roller to rupture the microcapsules on the non-woven fabric, let the UV absorber be absorbed by the non-woven fabric, and then dry . “The combination of disinfection and finishing microcapsules and anti-UV microcapsules can save outdoor workers from the trouble of direct sunlight and protect themselves from harm. It can be said to be the best of both worlds.” Klaus said.
Nanocapsules
Perfectly realize the superposition application of multiple functions
The British company Alkex is currently integrating nanotechnology and microcapsule technology and has developed nanocapsules that are still in the development stage. This nanocapsule has the advantages of both microcapsule encapsulation technology and nanoparticles, and has good development prospects in the field of nonwovens.
Texel, deputy technical director of Alkex Company, said that according to experimental results, nanocapsules can perfectly realize the superimposed application of multiple functions. The preparation of honeycomb fiber materials by embedding gas is a successful application.For example, the prepared nanofibers can be used in high-performance sports or space clothing materials; the rare earth far-infrared thermal insulation and health care material is another example of the application of nano-microcapsules in non-woven fabrics. The material is expected to be used in clothing linings, The production of bedding, shoes and hats, etc. has good medical and health care effects. In the near future, nanocapsules will also serve as sensors or drug carriers in fibers, playing a medical role.
“The company is currently trying to add fragrance products to non-woven materials treated with nano-microcapsules, so that the products can provide good performance while having an attractive smell.” Texel said.
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