[Ji Cuiwang observation] On February 26th, the first textile science and technology new insights academic salon was held in Beijing. Sharon discussed the development direction of flame retardant fiber and adhered to the concept of “Dare to question, be brave in innovation, tolerate failureâ€. Experts, research institutes, and enterprise representatives gave special speeches and in-depth discussions on the development trend of flame retardant fibers at home and abroad, the research and development of various major flame retardant fibers, and how to formulate more reasonable flame retardant testing standards.
“Performance was put up and the price dropped.†Participants agreed that the flame retardant fiber should be developed in the direction of medium and high performance, low and medium price, so as to be conducive to the market application and promotion of the product. The following is a collection of wonderful views of some of the speakers in the salon. I hope that these ideas can inspire relevant companies in theory and practical applications.
US flame retardant fiber and textile applications
Dr. Li Shulong, American Milliken Company
As the demand for safety and protection continues to increase, the US fire retardant textile industry is constantly evolving and renewing. Through the development of textile chemical technology and various fibers, many different types of flame retardant products have been widely used in a variety of end uses, such as flame retardant uniforms, industrial protective clothing, high temperature filtration, high temperature composite materials, flame retardant bedding Wait.
In such applications, textiles must not only meet the requirements of high temperature and fire resistance, but also meet other functional requirements, and the products must also have a price acceptable to the customer. For example, fire-retardant fire-resistant clothing must have good fire resistance, comfort, durability and stylish appearance.
For the same level of fire protection products, the lighter the weight, the more comfortable the hand feel is acceptable to the user. In the face of serious conflicts between fire protection performance and comfort performance, how to achieve the best protection performance and make the product comfort performance widely recognized by consumers is a big challenge for the industry.
The US flame retardant and fireproof textile industry is characterized by high quality, high reputation, high level of technical services and scientific research capabilities, as well as high levels of innovation and intellectual property protection. Flame-retardant and fire-retardant products must be trusted by consumers to reliably reduce injuries and protect lives. Companies need to not only develop and produce the best products and guarantee their high quality, but also ensure that consumers use the products properly and maintain them.
Recently, in the development of high-temperature new fibers in the United States, Saudi Basic Industries' amorphous PEI (polyetherimide) Ultem fiber and Magellan Systems International Co., Ltd. M5 fiber outstanding performance. Ultem fiber is relatively inexpensive, but high temperature performance is somewhat limited. M5 fibers have excellent mechanical, thermal and environmental stability properties, but are expected to be quite expensive. Therefore, M5 fiber may be limited to some high-end special field applications.
Structural properties and application of flame retardant vinylon
Professor Ye Guangdou, School of Polymer Science and Engineering, Sichuan University
The flame-retardant vinylon is produced by grafting a compound containing a flame retardant functional element (halogen, phosphorus, nitrogen, etc.) on a polyvinyl alcohol (PVA) macromolecule, or by adding a flame retardant, and then performing solution spinning. Flame-retardant vinylon is obtained by processes such as stretching, heat treatment and formalization.
At present, the main flame retardant vinylon varieties are: polyvinyl chloride, CY841 fiber (trade name of decabromodiphenyl ether/fluorene flame retardant vinylon), high strength flame retardant vinylon (decabromodiphenylethane flame retardant high strength vinylon), high strength and halogen free Flame retardant vinylon (flame retardant: DDPS flame retardant fiber). There are many varieties of flame-retardant vinylon, and the performance difference is large. It is the organic flame retardant fiber with the highest strength and no droplets in the textile industry.
Taking CY841 fiber as an example, the fiber uses decabromodiphenyl ether and antimony trioxide as flame retardants, and adopts ordinary wet spinning to produce flame retardant vinylon; decabromodiphenyl ether flame retardant vinylon is compared with ordinary vinylon. The difference in the core layer structure is small, and the flame retardant is uniformly dispersed in the fiber in a granular form, and the continuous phase is PVA, which is a flame retardant fiber with less flame retardant in the skin layer.
In terms of application, polyvinyl chloride is mainly used for: curtains, wall coverings, stage rafts, bedding, general clothing, overalls, industrial fabrics, filter cloths, etc.; second, for carpets, bedding, etc.; Non-woven fabrics, papermaking and other related fields.
High-strength flame-retardant vinylon has good flame retardancy and wear resistance, and can be purely or blended. Its fabric is mainly used for special occupational wear such as steel workers' overalls, fire-fighting suits and training uniforms.
Flame retardant viscose technology status and development trend
Xia Yulian, deputy chief engineer of Jilin Chemical Fiber Co., Ltd.
At present, there are mainly three manufacturing methods for flame retardant viscose fibers. One is an additive method (blending method), and the flame retardant is added to the spinning dope before spinning, and the flame retardant not only has excellent alkali resistance, acid resistance, heat resistance, but also is insoluble in a solvent such as water.
The second type is a flame-retardant finishing method in which a virgin fiber is treated with a nitrogen-containing organophosphate compound or a antimony trioxide and a halogen-containing flame retardant after the viscose fiber is produced or in the production process. The latex state is applied to the surface of the fiber.
The third type is graft copolymerization. The flame retardant reacts with the fiber macromolecular chain to make the reactive group with flame retardant effect tightly bound to the cellulose macromolecule, and the flame retardant effect is long lasting, but the operating conditions of the method Complex, a large amount of homopolymer is produced in the process, the fiber strength is lowered, the spinnability is deteriorated, and the development cost of the copolymer flame retardant is too high, and it has not been widely used, and the blending method is mainly used now.
At present, the flame retardant viscose fiber mainly faces two problems: First, the fiber structure: the main physical and mechanical properties of viscose fiber have a certain decrease in dry rupture strength and wet strength at the time of blending with flame retardant, although The process adjustment in the spinning process is still lower than the flame retardant viscose fiber produced by foreign similar production companies, which limits the application of flame retardant viscose fiber in some fields.
The second is the wet modulus of flame retardant viscose fiber: the biggest disadvantage of ordinary viscose fiber is the low wet modulus, and the same wet modulus of flame retardant viscose fiber. It is necessary to focus on the process of improving the wet modulus and improve the viscosity. The crystallinity and orientation of the rubber fiber, the technology of high-moisture modulus fiber is adopted, and the high-moisture modulus viscose fiber production technology is adopted to improve the wet modulus of the flame-retardant viscose fiber and broaden the application field of the flame-retardant viscose fiber.
Application of heat protection fiber in flame retardant field
Duan Shengwei, Engineer of Hangzhou West Lake Technology Co., Ltd.
The LENZING FR fiber developed by Austrian Lenzing Company uses wood pulp as raw material and uses the Lenzing Modal fiber technology to produce a flame retardant Sandflam 5060 which is equivalent to 20% dry weight of α-cellulose. The aqueous suspension emulsion is mixed and injected before spinning, and is directly input into the spinning portion by static mixing. The flame retardant medium has the characteristics of being non-toxic, insoluble, and halogen-free. And the addition of the flame retardant does not affect the natural whiteness, water absorption and hand of the fiber. Due to the Modal production process, the fiber maintains good fiber properties while maintaining excellent flame retardancy.
LENZING FR fiber has low heat shrinkage and good heat resistance. It is produced without hydrogen cyanide, hydrochloric acid and nitrogen oxide during combustion. The combustion of flue gas is even lower than that of non-flame retardant products. The fabric made of LENZING FR fiber has high whiteness and is comfortable and safe to wear, but should avoid high temperature dyeing when dyeing, so as to avoid the dye absorption too fast and cause the stain, and the drying temperature should not exceed 169 °C.
The main features of LENZING FR fiber include: blending with other fibers, adding clothing performance, wearing comfort, insulation and anti-burn effect, natural antistatic, excellent dyeing performance. However, Lenzing FR is also insufficient: because Lenzing Thermal Protective Fiber is a cellulose fiber, although it uses Lenzing's advanced Modal technology, its fiber strength is superior to ordinary flame retardant adhesive, but with other high performance flame retardant fibers such as aramid. In comparison, its strength is still low. Since flame-retardant protective clothing is mostly used in the field of tooling, the durability of the fabric is also an important indicator while ensuring the flame retardant performance. In addition, because Lenzing Thermal Protection Fiber is imported fiber, the high price is also a factor restricting its development in the domestic market.
The technical status and development direction of aramid
Song Xiquan, general manager of Shandong Yantai Taihe New Materials Co., Ltd.
The meta-aramid, the scientific name poly-m-phenylene isophthalamide fiber, is one of the fastest growing varieties of organic high temperature resistant fibers in the world. It was first developed by DuPont of the United States and industrialized in the late 1960s. In 1972, Teijin also began to produce meta-aramid with the trade name “Conexâ€. The earliest aramid production line in China was put into production in 2004 and was developed by Yantai Taihe New Materials Co., Ltd.
From the structural point of the meta-aramid molecule, the molecule is a linear macromolecule composed of an amide group interconnected with a meta-phenyl group. In its crystal, hydrogen bonds exist in two planes, such as a lattice, thereby forming a three-dimensional structure of the hydrogen bridge. Due to the strong role of hydrogen bonding, the chemical structure of meta-aramid is stable, with excellent heat resistance, good flame retardancy, chemical corrosion resistance, electrical insulation and mechanical properties. Aramid fiber is aerospace, Basic materials indispensable for high-tech industries such as military fire protection, electronic communication, energy conservation and environmental protection, and petrochemical industry.
Intrinsic flame retardant mechanism of seaweed fiber
Professor of Qingdao University, Xia Yanzhi, Ph.D. student Wang Bingbing
The essential flame retardant mechanism of seaweed fiber is mainly due to the new theory of flame retardation of metal ions. The flame retardant mechanism of metal ions is that metal ions act as catalytic cracking, change the thermal cracking process of alginic acid macromolecules, reduce the formation of combustibles, and promote their char formation; alginate macromolecules can pass metal ion chelation The cross-linked structure is formed, so that the pyrolysis temperature of the alginate fiber is higher than that of the alginic acid fiber; the metal ion in the macromolecule forms an alkaline environment during the combustion process, and the alginic acid macromolecule is highly susceptible to decarboxylation to form incombustibility. CO2 and dilute the flammable gas; the metal oxide and metal carbonate precipitate formed by the alginate fiber during the combustion process covers the surface of the fiber, forming a barrier between the condensed phase and the flame, isolating oxygen, and preventing the diffusion of flammable gas. .
Therefore, we conclude that alginate is a natural intrinsic flame retardant polymer with excellent flame retardant properties. Through experimental research and theoretical analysis, the flame retardant mechanism of such fiber materials is explained. The inherent metal ions act as a flame retardant, which we call the metal ion flame retardant mechanism.
The metal ion flame retardant theory is expected to be applied to the flame retardant modification of other natural polymers and synthetic polymer materials, and then to develop new flame retardant polymer materials.
Study on anti-melting droplets of melt-spun synthetic fiber
Zhu Shifeng, Ph.D., Donghua University
Thermoplastic fibers such as polyester, nylon, etc. will produce droplets during combustion. These high temperature drops can easily ignite other polymer materials, accelerate flame propagation and expand the scale of fire; if molten material sticks to the skin, Will burn the skin.
From the perspective of the mechanism of anti-melting, there are currently three ways to solve the problem of droplets:
One is to add fillers such as polytetrafluoroethylene powder to reduce the fluidity of the melt to prevent droplets; the other is to form a tight carbon layer on the surface when the fiber is burned, which acts as a protective layer to reduce the droplets; The structure of the polymer transforms the polymer from thermoplastic to thermoset to solve the droplet problem. Around these mechanisms, the researchers used blending, copolymerization, post-treatment, grafting and cross-linking methods to achieve the effect of preventing droplets or reducing droplets.
Radiation processing is one of the main application areas for the peaceful use of atomic energy in terms of the effect of high-energy ray irradiation on droplet performance. It is mainly a technology that uses radionuclide 60Co gamma rays and electron beams to process and process materials and materials.
The experimental analysis proves that the radiation cross-linking can promote the formation of charcoal, and has a certain improvement effect on the droplet properties of nylon 6, and the mechanical properties change is within the applicable range. The future work is to select suitable flame retardants to cooperate with them to achieve flame retardant and anti-melting droplets of nylon 6.
Structural properties of polyaryloxadiazole fibers
Xu Jianjun, Professor, School of Polymer Science and Engineering, Sichuan University
High temperature resistant flame retardant fiber is an important class of high-tech, high-performance fiber, which can be widely used in protective products, filter materials, electrical insulating materials, friction sealing materials, various industrial fabrics, high temperature resistant paper and aerospace materials. Waiting for high temperature resistance. Poly-1,3,4-oxadiazole (POD) is a high temperature resistant aromatic heterocyclic polymer material with good thermal stability, chemical stability and electrical insulation.
Through molecular structure design, we introduce a third monomer with ring-forming and flame-retardant function in the traditional POD molecular structure, optimize the polymerization conditions and formulation, and obtain high molecular weight, low viscosity (≤200 Pa.s), high ring. A spinning solution with a good degree of stability (≥90%) and good stability achieves a low viscosity target of high concentration (≥10%), so that the spinning solution can achieve medium and low pressure (≤100 °C) at a lower temperature (≤100 °C). 1.0MPa), small orifice diameter (≤0.1mm), multi-spinning hole (≥250 hole.cm-2) spinning.
By optimizing the function and ratio of the third monomer, the flame retardancy of Baodelun is greatly improved (the limiting oxygen index LOI≥30%), and the purpose of flame retardant modification is achieved, so that the Baodelun fiber has both general The performance of POD, with good flame retardant properties, has become a superior performance fiber variety than Oxalon.
Baodelun is a kind of high temperature resistant flame retardant fiber with excellent comprehensive performance. Its high temperature resistance is better than the high temperature resistant fiber varieties such as PPS, Nomex and Tanlon which are widely used at present. It has good corrosion resistance, good dyeability and wide range. Used in high temperature filter materials and flame retardant textiles.
Basic properties and research of polysulfonamide fiber
Zhang Yuhua, engineer of Shanghai Te Anlun Fiber Co., Ltd.
Polysulfonamide fiber, referred to as PSA, is called TANLON. It is developed by Shanghai Textile Research Institute and Shanghai Synthetic Fiber Research Institute of Shanghai Textile Group. High temperature resistant synthetic fiber of intellectual property. The successful development of polysulfonamide fiber has filled the gap of China's resistance to 250 °C grade synthetic fiber.
Aromatic sulfonamide is a special structure of aramid fiber, known as polyphenylsulfone terephthalamide fiber, which is composed of 4,4'-diaminodiphenyl sulfone, 3,3'-diamino A polycondensate of diphenyl sulfone and terephthaloyl chloride.
In the production, the polysulfonamide fiber changed the traditional process route of m-phenylenediamine as the second monomer adopted by other companies in the world, and introduced the benzene structure and the sulfone group, so that the amide group and the sulfone group are connected to each other. The phenyl group and the meta-phenyl group constitute a linear macromolecule. Due to the strong electron-withdrawing sulfone group -(SO2)- on the main chain of the macromolecule, the electron cloud density of the nitrogen atom on the amide group is significant through the conjugated system of the benzene ring through the double bond conjugated action of the benzene ring. It has a low heat resistance and flame resistance, and its long-term use temperature is 250 °C.
It has been proved by experiments that the heat resistance, high temperature dimensional stability, chemical resistance, hygroscopicity and dyeing performance of the polysulfonamide fiber are relatively good. Polysulfone fiber materials are widely used in protective products, high temperature filter materials, friction sealing materials, electrical insulation materials and other fields.
Flame retardant fiber detection technology
Luo Shengli, engineer of Guangzhou Fiber Products Inspection Institute
At present, the test methods for flame retardant performance of textiles include: horizontal combustion method, vertical combustion method, 45o combustion method, oxygen index method, etc. Different test methods reflect the combustion performance of the fabric from different sides. The evaluation of the flame retardant properties of textiles generally uses the following indicators: afterburning time, smoldering time, length of damage, flame spread time, flame spread rate, flame spread distance, burning speed, minimum ignition time, limiting oxygen index, dimming coefficient, Radiation flux, etc.
The textile flame retardant test standard system mainly has the following problems:
First, there are many indicators, there are repetitions, and they must be simplified. For example, the "flame spread time, flame spread rate, flame spread distance, burning speed" indicators actually express a meaning, that is, the burning speed.
Second, the current flame retardant performance index of textiles is mostly to evaluate the ease of burning and the degree of burning.
Third, the existing standard system is mainly for the flame retardant test method of fabrics, not loose fibers. Because the burning properties of textile materials are not only related to the properties of the materials themselves, but also related to the structure of the fibers, the blending situation and so on. However, the flame retardant test method and standard blank of the fiber restrict the development and market promotion of the flame retardant fiber product. If the fiber is spun into a cloth for each test, and then the combustion performance of the sample is tested, the test cycle will be very Long, high cost and other adverse effects.
In addition, once the flame retardant fiber encounters quality disputes in trade, it is difficult to distinguish the responsible party. Therefore, in October 2011, China released three industry standards for fiber flame retardant performance testing, namely polyester fiber and viscose staple fiber. The flame retardant properties of inorganic flame retardant viscose staple fibers were tested by the limiting oxygen index method.
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