A brief discussion on “flame retardant finishing” technology for textile items
Basic concepts and progress
Fire-proof finishing: Fabrics that have been treated with certain chemicals can prevent them from burning when exposed to fire, or they can extinguish as soon as they are ignited. This treatment process is called fire-proof finishing, also known as fire-proof finishing. Fire retardants are compounds containing elements such as phosphorus, nitrogen, chlorine, bromine, antimony, and boron.
Fire-resistant finishing fabrics can be used in military departments, industrial transportation departments, and civilian products, such as carpets, curtains, curtains, work clothes, bedding, and children’s work clothes.
Records of fireproof finishing of fabrics have been recorded since the 17th century. In recent years, fires caused by fabrics have been increasing in countries around the world. In the past ten years or so in our country, the average number of fires occurring each year has been 30,000 to 40,000, with 2000 to 3000 deaths, and fire losses of 200 to 300 million yuan. In 1985, a fire at the Swan Hotel in Harbin killed ten people and injured seven, with a direct economic loss of 249,000 yuan. In 1994, a fire in Karamay killed more than 300 people, all caused by burning fabrics.
Research and development of fire-proof fibers – The research and development of fire-proof fibers in my country started in the 1970s; from the 1980s to the present, some scientific research units and colleges in Shanghai, Jilin, Shandong, Guangdong, Tianjin, Sichuan, Beijing, Jiangsu and other provinces and cities And factories have successively conducted research on fire-resistant fibers. Polyester and polypropylene have formed mass production capabilities, but generally speaking, fire-resistant fiber products are still in the research and trial stage.
Fabric products treated with fireproof finishing technology
Specific applications of fireproof finishing technology
(1) Fireproof finishing of cotton fabrics
The fireproof finishing of cotton fabrics is progressing rapidly. At present, the country is relatively mature. Fireproofing agents are basically self-sufficient and can be industrialized.
There are generally three methods for durable fireproof finishing of pure cotton:
1. Proban/ammonia fumigation process. The Proban method was first used in industrial production by the British Wilson Company. The traditional Proban method is a baking process after padding with the fire retardant THPC (tetrahydroxymethyl chloride). The improved method is Proban/ammonia fumigation. The process, the process flow is: padding and fireproofing → drying → ammonia fumigation → oxidation → water washing → drying.
In China, Beijing Wanhua, Jiangyin Printing and Dyeing Factory, Anshan Cotton Textile Printing and Dyeing Factory, etc. have introduced foreign auxiliaries and equipment for production. This is a process that is currently recognized as having good fireproofing effect, small fabric strength reduction, and little impact on hand feel. However, equipment problems have limited its promotion.
2. PyrovatexCP finishing process. Domestic units such as Shanghai Pesticide Factory, Changzhou Chemical Industry Research Institute, Tianjin Composite Materials Research Institute, East China University of Science and Technology, and Qingdao Textile Workwear College are producing this additive. The product has good fireproof performance and good durability. It can withstand household cleaning for 50 or even more than 200 times. It feels good, but the strength reduction is slightly larger. There are 20 to 30 domestic manufacturers using this type of fire retardant.
Temporary and semi-durable fire-retardant finishing of pure cotton – Electric blankets, wall coverings, sofas and other fabrics do not require very high fire-resistance and washing times. Such products can be used for temporary or semi-durable fire-retardant finishing. Can. That is to say, it can withstand 1-15 times of gentle air cleaning, but it is not resistant to soaping. There are mainly borax-boric acid process, diammonium hydrogen phosphate process, phosphoramide process, dicyandiamide process, etc. The above process is rarely used in industrial production of pure cotton fabrics. SFR-203 from Qingdao University Fabric Workwear College is a semi-durable fireproof finishing agent.
(2) Fireproof finishing of wool fabrics
Wool has a high moisture regain rate and ammonia content, so it has good natural fire resistance. However, if higher standards are required, it needs to be post-fireproofing. The earliest fire-proof finishing of wool used borax and boric acid solution dipping method, and the product was used for decorative cloth on aircraft. This method has good fire protection effect, but it is not resistant to water washing. After the 1960s, THRC treatment was adopted, which has better washing resistance, but the process is complicated, the hand feels rough, and the quality of wool fabric is lost. The method studied by the International Wool Bureau is to use a complex of titanium, zirconium and hydroxy acid to post-finish wool fabrics to achieve a satisfactory fire-proof effect without affecting the feel of wool, so it has been widely adopted. Mainly include titanium, zirconium, tungsten and other metal complex finishing agents. Since the late 1980s, several domestic units have researched and developed wool fire retardants and post-finishing processes, and have achieved satisfactory results. Tianjin Institute of Synthetic Materials has developed a series of conformable WFR-866 fire retardants, one is WFR-866F (with fluorine complex as the main component), and the other is WFR-866B (with bromine-containing hydroxy acid as the main component) ). Tianjin Renzhan Woolen Mill, Beijing Woolen Mill, and Beijing Woolen Mill all use Lu fire retardant to treat fine and woolen products. Qingdao University School of Textile Workwear has developed SFW series wool fire retardants, and cooperated with Jining Woolen Mill and Weifang Second Woolen Mill to develop pure wool fire retardant products. The fire retardant performance of the products has reached or exceeded the level of similar products at home and abroad.
Currently, pure wool fireproof fabrics are mainly used in carpets, curtains, wall materials in aircraft cabins, high-end hotels, and military uniforms for military officers and above.
Fireproof finishing of synthetic fiber and its blended chemical fiber fabrics
(3) Fireproof finishing of polyester fabric
Fireproof finishing of polyester fabrics So far, a suitable ideal fireproofing agent has not been found. Tris(2.3-dibromopropyl)phosphate (TDBPP) has a certain effect on polyester fire protection, but it has carcinogenic effects. Mobilchemco of the United States has launched Antiblaze19T fire retardant, suitable for 100% polyester fabric, good effect and not very toxic. FRC-1 manufactured by Changzhou Chemical Industry Research Institute in China is a similar product. Changzhou Knitted Fabric Factory and Shanghai Knitted Fabric Factory use this fire retardant to produce pure polyester knitted fabrics. In addition, finishing agents containing bromine and antimony compounds such as decabromodiphenyl ether, hexabromocyclododecane, antimony trioxide, antimony pentoxide, etc. have been studied. Adding binders to the working fluid will Fire retardants are bonded to the fabric. But in general, the fire resistance of the finished fabric is acceptable, but it feels hard, has hoarfrost, discoloration, etc., and the stability of the finishing fluid is not good. The main reason is that the fire retardant has large particle size, is easy to agglomerate, and has poor adsorption to fibers. According to foreign reports, if the particle size is 15-20nm, the fireproof effect can be increased by 3 times, the hand feel is soft, and the washability is good.
Domestic research on polyester fabrics includes: Changzhou Chemical Industry Research Institute, Changzhou Knitted Fabric Factory, Changshu Weft Knitting Factory, Liaoning Warp Knitting Factory, China Textile University, Qingda University Fabric Workwear College, Shijiazhuang Textile Warp Knitting Factory Factory etc.
(4) Fireproof finishing of polyester fabric
Phosphorus and halogen fire retardants used in other fibers are not effective as nylon fire retardants. Hebei University uses hydroxymethylurea resin to treat nylon cloth for conveyor belts, with good results. Qingdao University School of Fabric Workwear used compounds containing sulfur, bromine, and antimony to finish the fireproof PU coating on nylon taffeta, and achieved good results.
(5) Fireproof finishing of polyacrylonitrile fiber fabric
Polyacrylonitrile fiber is more flammable than polyester and nylon, with an oxygen index of only 18-18.5, making it an easy-to-burn fiber. The School of Fabrics and Workwear of Qingdao University has researched and developed a series of fire retardant agents for polyacrylonitrile fiber sheared decorative fabrics. It has a fire-retardant PU coating on the back of the suede fabric. The product has an Oxygen Number of more than 29 and a carbon length of less than 8 cm, which is basically non-stop. Naturally, smoldering, the developed polyacrylonitrile fiber sheared decorative cloth can be used in sofa cloths and decorative cloths for cars, airplanes, hotels and homes.
(6) Fireproof finishing of polyester-cotton blended chemical fiber fabrics
Polyester-cotton blended chemical fiber fabrics are used in large quantities, and the research on their fireproof products is also quite active. Polyester and cotton are two types of fibers with different combustion properties. At the same time, blending chemical fiber fabrics makes the combustion process more complicated. Cotton fibers are carbonized after burning, while polyester melts and drips when burned. Because the cotton fibers become a support, the molten fibers can gather and prevent them from dripping, making the molten fibers burn more violently, which is the so-called “scaffold effect.” Therefore, the fireproof finishing of polyester-cotton blended chemical fiber fabrics is more difficult.
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