New product Ultem resin all-purpose flame retardant fiber
GE is expanding the application of fibers made from Ultem resin to other productions such as home decoration, gas filtration, transmission fabrics and fabrics, and seating materials.
1. Foreword
Ann Marie Lak, global technical manager for fibers and fabrics at GE Plastics, a subsidiary of General Motors, and Youssef Fakhreddine, global market industrial manager, promoted its new Ultem fireproof material in International Fiber Magazine. It is reported that the state of California in the United States has announced extremely strict fire protection regulations for mattresses. This will undoubtedly promote progress in fireproof material production research. The company’s Ultem resin material is specifically designed to meet the California Technical Bulletin (TB) 603 standard for bedding fire protection requirements.
2. General situation
Polyetherimide (PEI) resin is widely used in materials that need to be fireproof and prevent the spread of smoke. It helps manufacturers of mattresses, Simmons and other products to produce products that prevent open flames from accelerating combustion.
The company has never used Ultem resin to produce fiber materials in the past, but its scientific and technical personnel are not afraid of the hardships, and downstream manufacturers have begun to evaluate its potential functions for high-energy fabrics and conduct research
California’s TB603 standard will be implemented soon, sending a warning to bedding manufacturers, who often use polyurethane foam and polyester batting to make products. California standards set out technical requirements, including the use of high-performance materials and different mattress designs, to address this issue.
Another related issue is that halogen material fire retardants can release toxic fumes. EU regulations on Restriction of Hazardous Goods (RoHS) strictly prohibit the use of polybrominated diphenyl ethers (PBDE) often contained in fire retardants. It is estimated that California’s standards will be adopted by other regions, such as the national standards recently announced by the Consumer Safety Commission (CPSC), which require manufacturers to ensure that fireproof materials can meet various market regulatory requirements.
3. Research and development process
Resin is an unshaped high-performance polymer that exhibits outstanding high temperature resistance, good strength, large modulus, broad-spectrum chemical resistance, inherent combustion resistance and low smoke-generating properties; glass transition (transition) temperature With a relative thermal index (RTI) of 217°C and 170°C, this polymer can maintain strength and integrity at high temperatures.
Resin products have experienced long-term testing in safety facilities and situations requiring strict fire protection standards, such as firefighter helmets, interior decoration materials for airplanes and trains, etc. These are the products that can be used as mattresses and bedding. Materials are key factors.
Resin has an unshaped structure and high temperature resistance, which makes it difficult to extract fibers. Because it is an amorphous (non-crystalline) material, it has a higher viscosity than a crystal, making it more difficult to pass through the small holes of the spinneret when spinning. The small-hole spinneret is used for spinning woven fabrics and non-woven fabrics. Need for finer fibers. Crystalline materials, such as polyester and polypropylene, not only pass through small holes more smoothly during spinning, but they can also be spun finer by stretching after extrusion. Crystalline polymers are stretched to straighten and align the molecular chains, making the fibers stronger and more stable. On the contrary, stretching amorphous resins, such as Ultem and other materials, produces stress that shrinks when the fibers are heated, so the fibers are stretched. There is trouble. When extruding Ultem resin, the spinneret hole diameter must be extremely small, but this will affect the operation time of the spinneret assembly.
The melting temperature of Ultem resin is relatively high, reaching 375-400°C, which is higher than that of conventional spun fiber resin materials, so there are fewer ready-made equipment for processing this resin. There are unsafe factors in increasing the temperature of conventional heating equipment, such as electric heaters and hot oil channels. GE needs to find collaborators with R&D and large-scale production who have corresponding finishing equipment and finishing capabilities. In early 2003, GE cooperated with an American company. The company specializes in processing thermoplastic polymers, including unusual materials like Ultem resin, to produce synthetic fibers through a melt-spinning process.
4. Optimize production process
The company and its downstream manufacturers have solved some technical problems and successfully spun a batch of Ultem fiber products
First of all, the resin itself must be refined to make it more suitable for the spinning process, especially the tiny spinning holes for spinning finer fibers. Most of GE’s resin products are used in injection molding production, and the finishing parts are thicker than those produced by spinning. The sensitivity of the fiber extraction process prompted GE to improve the resin properties to adapt to its finishing sensitive characteristics.
Secondly, the equipment of downstream finishing manufacturers must meet some extraordinary requirements for Ultem resin, such as resistance to high temperatures of 400°C, uniform temperature distribution, short residence time (the time the resin material is in a hot state), and no more than 10 minutes to prevent degradation, low shear (also to prevent degradation), low throughput (relative to polyester resin materials, etc.) to accommodate the higher viscosity of Ultem resin.
After that, the process parameters of the finishing process are optimized, including temperature, production speed and pressure. The resin is sorted according to the normal melt extrusion process. The slices are first dried, melted in the extrusion head, passed through the multifilament spinning assembly, and stretched. , wound into a bobbin through the godet. GE and finishers must grasp the impact of spinning hole size on the final fiber diameter, control the relationship between melt temperature and melt strength, and draw ratio to obtain good fiber stability. The main performance indicators of the fiber with a single filament fiber density of 10 denier:��：
Density (g/cm?) 1.27 Water absorption (℅)
Limited Oxygen Index (LOI) 44 Strength (g/d)
Elongation at break (℅) 40 Modulus (g/den)
Initial research work was focused on producing 10dpf fiber for mattress barrier fabrics in response to upcoming California regulations. They started producing coarser fibers for simplicity and feasibility, and planned to gradually develop finer products for mass production.
With the success of the small-scale pioneering test of 10-denier fiber, GE is confidently collaborating with Restonic Mattress Corp (mattress company) to use Ultem fiber to manufacture new mattress materials that comply with TB 603 standards. Ultem fiber is made by Western Nonwovens into a fire-resistant barrier material and placed between the mattress’s foam core and outer fabric to become Restonic’s Ergo Sleep? mattress product – which only meets California standards and is certified by UL ?Certified mattress pad. The use of Ultem resin makes the barrier material itself fire-resistant. Ultem fiber can also be easily made into a barrier material several centimeters thick, with good resilience and comfortable use.
Currently, GE and its finishers can produce batches of Ultem fiber products with a single filament fineness of 10 denier, and are conducting research on spinning finer fiber materials. The key to producing finer fibers is the viscosity of the resin and its ability to stretch the fiber. The solution is to further refine the material and improve the design of the spinneret. There are already a large number of samples of 6-denier and 4-denier fibers produced by Ultem resin, and efforts are being made to achieve successful large-scale production of 2-denier fibers. The company also plans to cooperate with downstream finishing plants in other regions and the United States.
5. Advantages and applications
The fiber made of the company’s Ultem resin has many advantages. Since it is a fireproof material, it can adapt to the restrictions of no longer using halogen additives; it complies with TB603 and CPSC new standards regarding the performance requirements of mattress products when exposed to open flames. . Ultem’s amorphous structure and high temperature resistance make it suitable for many high-temperature applications where fibers made from crystalline polymers lose strength when exposed to high temperatures.
The company is expanding the use of fibers made from Ultem resin in other productions such as home decoration, gas filtration, transmission fabrics and fabrics, and seating materials.
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