1 Introduction
Affiliated to General Motors, Ann Marie Lak, Global Technical Manager for Fibers and Textiles at GE Plastics, and Youssef Fakhreddine, Global Market Industry Manager, presented their new Ultem flame retardant materials at International Fiber Magazine. It is reported that California has published extremely strict mattress flame retardant regulations. This will undoubtedly promote the development of research on the production of fireproof materials.
GE's Ultem resin material is ideally suited to meet the California Technical Bulletin (TB) 603 standard for bedding flame retardant requirements.
2, the general situation
Ultem polyetherimide (PEI) resin is widely used in materials that require flame retardant and smoke diffusion, and helps manufacturers such as mattresses and Simmons to produce products that prevent accelerated burning of open flames.
GE has never used Ultem resin to produce fiber materials in the past, but its scientists are not afraid of hardships, and downstream manufacturers are beginning to evaluate the potential functions of high-energy fabrics and conduct research.
The California TB603 standard is about to be implemented, warning the bedding manufacturer that the latter uses polyurethane foam and polyester foam to make the product. The California State Standards set forth technical requirements, including the use of high-performance raw materials and different mattress designs to solve this problem.
Another related issue is that halogen flame retardants release toxic fumes. The European Union's regulations on dangerous goods (RoHS) strictly prohibit the use of polybrominated diphenyl ether (PBDE), which is often found in flame retardants. California standards are expected to be adopted in other regions, such as the recent National Standards announced by the Consumer Safety Commission (CPSC), which requires manufacturers to ensure that flame retardant materials meet various market regulations.
3. Research and development process
GE Ultem resin is an amorphous high performance polymer that exhibits excellent high temperature resistance, good strength, high modulus, broad spectrum chemical resistance, inherent combustion resistance and low smoke generation. The glass transition temperature is At 217 ° C and a relative heat index (RTI) of 170 ° C, this polymer maintains strength integrity at high temperatures.
Ultem resin products have been used in long-term tests in safety facilities and in places where strict flame retardant standards are required, such as firefighter helmets, aircraft and train interior materials, etc. These are the materials that can be used as mattresses and bedding materials. The key factor.
Ultem resin is an amorphous structure and has high temperature resistance, which makes it difficult to draw fibers. Because it is an amorphous (amorphous) material, it has a high viscosity compared to the crystal, making it more difficult to pass through the orifice of the spinneret during spinning, while the small orifice spinneret is used for spinning woven and nonwoven fabrics. The need for finer fibers. Crystalline materials, such as polyester and polypropylene, not only pass through the small holes when spinning, but also can be spun finer after extrusion. The crystal polymer is stretched and straightened to align the molecular chain, so that the fiber strength is increased and more stable; on the contrary, the tensile stress of the amorphous resin, such as Ultem, causes shrinkage when the fiber is heated, so Struggling. When the Ultem resin is extruded, the orifice diameter must be as small as possible, but this will affect the running time of the spinneret assembly.
GE's Ultem resin has a higher melting temperature of 375-400 ° C, which is higher than that of conventional spun fibers, so there are fewer off-the-shelf equipment for processing such resins. Increasing the temperature of conventional heating equipment, such as electric heaters and hot oil passages, is an unsafe factor. GE needs to find collaborators with the development and scale of production of the corresponding processing equipment and processing capabilities. In early 2003, GE worked with a US company. The company specializes in the processing of thermoplastic polymers, including unusual materials such as Ultem resins, which produce synthetic fibers through a melt spinning process.
4. Optimize the production process
GE and its downstream producers solved some technical problems and successfully spun the first Ultem fiber products.
First of all, the resin itself must be finished to make it more in line with the spinning process, especially for the tiny spinning holes that spin finer fibers. GE's resin products are mostly used in injection molding, and the processed parts are thicker than those produced by spinning; the sensitivity of the process of pumping fibers has prompted GE to improve resin properties and adapt to its processing sensitivity.
Secondly, the equipment of downstream processing manufacturers must meet some special requirements for adapting to Ultem resin, such as high temperature resistance of 400 °C, uniform temperature distribution, short residence time (resin material is in hot state), and can not exceed 10 minutes to prevent Degradation, low shear (also to prevent degradation), low yield (relative to polyester resin materials, etc.) to accommodate the higher viscosity of Ultem resin.
Finally, optimize the process parameters of the process, including temperature, production speed and pressure, etc., the resin is processed according to the normal melt extrusion process, the slice is dried first, melted in the extrusion head, passed through the multifilament spinning component, stretched, guided The wire is wound into a bobbin. GE and processors have an understanding of the effect of spinning hole size on the final fiber diameter, and the relationship between melt temperature and melt strength and draw ratio to achieve the best fiber stability. The main performance indicators of the fiber with a monofilament of 10 denier are:
Density (g / cm 3) 1.27 water absorption rate (c / o) 0.25
Oxygen limit index (LOI) 44 intensity (g / den) 2.2
Elongation at break (c/o) 40 modulus (g/den) 30.3
The initial research work was directed at the forthcoming California regulations, which were dedicated to the production of 10dpf fibers for the use of barrier mat fabrics. They began to produce thicker fibers for the sake of simplicity and feasibility, and plans to gradually develop more elaborate product mass production.
With the success of the small-scale pilot project of 10 denier fibers, GE confidently collaborated with Restonic Mattress Corp to create new mat material that meets the TB 603 standard using Ultem fiber. Ultem fiber is made of flame-retardant barrier material from Western Nonwovens, placed between the foam core of the mattress and the outer fabric, and becomes the Ergo Sleep® mattress of Restonic – the first to meet California
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