Water-based technology to produce polyurethane and polyester/polyamide microfibers
Nonwoven‐based polyurethane and polyester/polyamide microfibers (generally known as suede) are increasingly used in many fields of application and in a diversity of products.
The most used and popular technology for the production of nonwoven is a method involving different solvents and processing aids during the production in order to give the fibers the physical and mechanical characteristics required. This case story describes an alternative technology to produce microfibers using water as the only solvent. The technology, called Dinamica®, developed by Miko and patented by the Japanese partner Asahi Kasei also gives the materials flame retardant properties without the addition of chemical flame retardants.
An alternative technology allowing complete substitution and/or elimination of different organic solvents normally used in this process.
This technology allows the elimination of organic solvents traditionally used for production of microfibers. Solvents commonly used: tri-and tetrachloroethylene and dimethylformamide (DMF). The material also allows the replacement of chemical flame retardants such as antimony trioxide, pentabromophenyl, decabromodiphenyloxide and other halogenated compounds. All of these chemicals are well known for having hazardous properties posing risk to workers and to the environment.
Nonwoven‐based polyurethane and polyester/polyamide microfibers (generally known assuede) are increasingly used in the following fields of application:
‐ home application (furnishing and upholstery)
‐ car interiors
‐ air‐plane seating
The most used and popular technology for the production of nonwoven is the traditional method (carding and needle punching) in which the microfibers are produced with the sea island technology. Islands of microfibers (PES/PA) are spun in a matrix (sea) of another polymer, which protects the microfiber during machining. Such a matrix is then dissolved in a later stage.
The matrix that ensures the best performances in terms of hardwearing resistance is polystyrene or its copolymers. Trichloroethylene is normally used for dissolution of polystyrene and its copolymers. The needle‐punched TNT is then impregnated with polyurethane, which besides giving particularly appreciated tactile features, acts as a binder and provides the resistance to wear.
Polyurethanes are normally used for these applications and usually dissolved in DMF and applied through the process widely used for manufacturing of man‐made leather called coagulation.
The application areas mentioned requires fire retardant properties of the material. To obtain this, the material is typically coated with compounds based on antimony oxide and decabromodiphenyloxide = pentabromophenyl ether or other halogenated compounds.
Miko has developed a new line of products called Dinamica®, which eliminates all the harmful chemicals mentioned above. The microfiber used in the product comes from recycled PES (reducing CO2 emissions and increasing energy savings) through a technology known as direct spinning. Therefore there is no need to dissolve the sea component with trichloroethylene. The nonwoven production process is called wet laid combined with spun lace (water needling). This technology is less invasive than conventional microfiber and does not need the use of protective matrix.
The product uses waterborne PU or, in some cases, is exempt from PU. Therefore also the DMF is not used in the production cycle. The company has solved the problem of fire resistance making the product inherently flame retardant without the need to use harmful products.
This is due the structure of the product which consists of three layers (surface, inner scrim and back). Specific products have been developed to meet the fire safety requirements for each of the different applications described in the beginning.
Miko is an Italian company founded in 1997, Dinamica® by Miko is an ecological microfiber made from recycled polyester. The product was the winner of the Italian Environmental Business Award 2011 for Best Product. Miko is partner of Asahi Kasei, a Japanese company, which provides the raw base for the production of Dinamica®. The company offers products for different types of applications. For the production the company does not use harmful solvents and uses only neutral and non‐toxic dyes. Its production cycle is based on a unique water process in order to guarantee fully respect for human health and the environment.
This case story describes a new technology developed to eliminate a number of hazardous chemicals used in the production of microfibers. The technology also uses recyclable materials which is favourable also from a resource efficiency point of view.
Type of information supplier
Producer / distributor
Company name: Miko Srl – via Ressel, 3 – Gorizia 34170
Contact: Benedetta Terraneo, marketing manager – firstname.lastname@example.org
Publication or last update: 04.02.2013