The history of nylon was developed by Carothers, a prominent American scientist, and a team of scientists under his leadership. It is the world's first synthetic fiber. The emergence of nylon has renewed the face of textiles. Its synthesis is a major breakthrough in the synthetic fiber industry and an important milestone in polymer chemistry.
In 1928, DuPont, the largest chemical industry company in the United States, established the Institute of Basic Chemistry. Dr. Carothers, only 32 years old, was employed as the director of the institute. He is mainly engaged in the research of polymerization. He first studied the polycondensation reaction of difunctional molecules and synthesized long-chain, high-molecular-weight polyesters by esterification condensation of dihydric alcohols and dicarboxylic acids. In less than two years, Carothers has made important progress in the preparation of linear polymers, especially polyesters, increasing the relative molecular mass of the polymer to 10 000 to 25,000. Polymers with a mass greater than 10,000 are called Superpolymers. In 1930, Carothers's assistant discovered that high-polyesters obtained by polycondensation of dihydric alcohols and dicarboxylic acids could be melted like cotton candy, and even if such filaments were filamentous After cooling, it can continue to stretch, and the stretching length can reach several times. After cooling and stretching, the strength, elasticity, transparency and gloss of the fiber are greatly increased. The unusual properties of this polyester make them anticipate that it may have significant commercial value and it is possible to spin the fibers with molten polymers. However, continued studies have shown that obtaining fibers from polyester has only theoretical significance. Because high-polyester melts below 100 °C, it is especially soluble in various organic solvents, but it is only slightly stable in water, so it is not suitable for textiles.
Carotherth then conducted in-depth research on a series of polyester and polyamide compounds. After a number of comparisons, he selected polyamide 66, which was first synthesized from hexamethylenediamine and adipic acid on February 28, 1935 (the first 6 represents the number of carbon atoms in the diamine, and the second 6 represents the amount of diacid in the Carbon atoms). This polyamide is insoluble in common solvents and has a melting point of 263 °C, which is higher than the usual ironing temperature. The drawn fiber has a silky appearance and luster, and is similar in structure and properties to a natural silk, its abrasion resistance and strength. More than any kind of fiber at the time. Considering its properties and manufacturing costs, it is the best choice among known polyamides. DuPont then solved the industrial source problem of producing polyamide 66 raw materials. On October 27th, 1938, it officially announced that the world's first synthetic fiber was born, and named polyamide 66 as nylon (Nylon). . Nylon was later used in English as a generic term for all polyamides that were synthesized from coal, air, water, or other substances, and that have abrasion resistance and flexibility, similar to the chemical structure of proteins.
Nylon 6 and Nylon 66
* Structure: Nylon 6 is polycaprolactam, and Nylon 66 is polyhexamethylene adipate. Nylon 66 is 12% harder than nylon 6, and theoretically, the higher the hardness, the more brittle the fiber and the easier it is to break. However, this slight difference in the use of carpets cannot be differentiated.
* Cleaning and anti-fouling properties: The effect of these two properties is the cross-sectional shape of the fiber and the subsequent anti-fouling treatment. The strength and hardness of the fibers themselves have little effect on cleaning and antifouling properties.
* Melting point and elasticity: The melting point of nylon 6 is 220C and the melting point of nylon 66 is 260C. However, this is not a difference for the temperature conditions of the carpet. The lower melting point makes nylon 6 have better resilience, fatigue resistance and thermal stability than nylon 66.
* Color fastness: Color fastness is not a characteristic of nylon. It is a dye in nylon rather than nylon itself that fades under light.
* Abrasion resistance and dust resistance: A two-and-a-half-year experiment was carried out by Clemson University in the United States with BASF Zeftron500 nylon 6 carpet and DuPont Antron XL nylon 66 carpet respectively at Tampa International Airport. The rug was in a state of high traffic. The results showed that: BASF Zeftron 500 nylon is slightly better than DuPont Antron XL in color retention and pile wear resistance. There is no difference in the dust resistance of the two yarns.
Nylon modification Because nylon has many characteristics, it is widely used in automobiles, electrical equipment, mechanical parts, transportation equipment, textiles, and papermaking machinery.
As the miniaturization of automobiles, the high performance of electrical and electronic equipment, and the lighter weight of mechanical equipment are accelerated, the demand for nylon will be even higher. In particular, nylon, as a structural material, places high demands on its strength, heat resistance, and cold resistance. The inherent disadvantage of nylon is also an important factor limiting its application, especially for the PA6, PA66 two varieties, compared with PA46, PAl2 and other varieties have a strong price advantage, although some properties can not meet the requirements of the relevant industry development. Therefore, it is necessary to expand its application area by modifying and improving certain properties for an application field. Mainly in the following aspects to modify.
1 Improve the water absorption of nylon and improve the dimensional stability of the product.
2 To improve the flame retardancy of nylon to meet the requirements of the electronics, electrical, telecommunications and other industries.
3 Improve the mechanical strength of nylon to achieve the strength of metal materials, replace metal 4 to improve the low temperature resistance of nylon, and enhance its ability to resist environmental strain.
5 to improve the wear resistance of nylon to meet the wear and demand of high occasions.
6 Improve the antistatic properties of nylon to meet the requirements of mines and their mechanical applications.
7 Improve the heat resistance of nylon to meet the requirements of high temperature conditions such as automotive engines.
8 Reduce the cost of nylon and increase product competitiveness.
In short, through the above improvements, the high-performance and functionalization of nylon composite materials is realized, and the development of high-performance, high-quality products in related industries is promoted.
The latest development of modified PA products mentioned earlier that glass fiber reinforced PA was studied in the 1950s, but industrialization was formed in the 1970s. Since 1976, DuPont Co., Ltd We have developed new modified PA products. The United States, Western Europe, Japan, the Netherlands, and Italy have vigorously developed PAs, PAs, PAs, and a large number of modified PAs.
In the 1980s, the development of compatibilizer technology was successful and promoted the development of PA alloys. Countries around the world developed PA/PE, PA/PP, PA/ABS, PA/PC, PA/PBT, PA/PET, PA/ PPO, PA/PPS, PA/I. Thousands of alloys such as CP (liquid crystal polymer) and PA/PA are widely used in industries such as automobiles, motorcycles, electronics, electrical machinery, textiles, sporting goods, office supplies, and home appliance parts.
In the 1990s, new varieties of modified nylons continued to increase. During this period, modified nylons became commercialized, new industries were formed, and they developed rapidly. At the end of the 1990s, the world production of nylon alloys reached 1.1 million tons/year. .
In terms of product development, the company mainly focuses on high-performance nylon PPO/PA6, PPS/PA66, toughened nylon, nano-nylon, and halogen-free flame-retardant nylon; in terms of application, significant progress has been made in the development of automotive parts and electrical components, such as The use of high-flow modified nylon for automotive intake manifolds has been commercialized. The plasticization of this structurally complex component has great significance in terms of applications, and it is more important to extend the life of components and promote the engineering plastics processing technology. development of.
Development Trend of Modified Nylon As the largest and most important product in engineering plastics, Nylon has strong vitality, mainly due to its high performance after modification, followed by automotive, electrical, telecommunications, electronics, and machinery industries. The requirements for high performance are getting stronger. The rapid development of related industries has promoted the progress of high-performance engineering plastics. The future development trend of modified nylon is as follows.
1 The market demand for high-strength and high-rigidity nylon is increasing. New reinforcing materials such as inorganic whisker reinforcement and carbon fiber-reinforced PA will become important varieties, mainly for automotive engine parts, mechanical parts and aviation equipment parts.
2 Nylon alloying will become the mainstream of the development of modified engineering plastics. Nylon alloying is an important way to realize the high performance of nylon, and it is also the main means for manufacturing nylon special materials and improving the performance of nylon. By blending other polymers, the water absorption of nylon is improved, the dimensional stability of the product is improved, and the low-temperature brittleness, heat resistance, and wear resistance are improved. As a result, it is suitable for different types of applications.
The manufacturing technology and application of 3-nanometer nylon will be rapidly developed. The advantage of nano-nylon is that its thermal properties, mechanical properties, flame retardancy, and barrier properties are higher than that of pure nylon, and the manufacturing cost is comparable to that of back-pass nylon. Therefore, it is very competitive.
4 The flame-retardant nylon used in electronics, electrical appliances, and electrical appliances is increasing day by day, and the green flame-retardant nylon is getting more and more attention from the market.
5 Antistatic, conductive nylon and magnetic nylon will become the preferred materials for electronic equipment, mining machinery and textile machinery.
6 The research and application of processing aids will promote the functionalization and high performance of modified nylons.
7 The application of comprehensive technology, the refinement of products is the driving force for the development of its industry.
In 1928, DuPont, the largest chemical industry company in the United States, established the Institute of Basic Chemistry. Dr. Carothers, only 32 years old, was employed as the director of the institute. He is mainly engaged in the research of polymerization. He first studied the polycondensation reaction of difunctional molecules and synthesized long-chain, high-molecular-weight polyesters by esterification condensation of dihydric alcohols and dicarboxylic acids. In less than two years, Carothers has made important progress in the preparation of linear polymers, especially polyesters, increasing the relative molecular mass of the polymer to 10 000 to 25,000. Polymers with a mass greater than 10,000 are called Superpolymers. In 1930, Carothers's assistant discovered that high-polyesters obtained by polycondensation of dihydric alcohols and dicarboxylic acids could be melted like cotton candy, and even if such filaments were filamentous After cooling, it can continue to stretch, and the stretching length can reach several times. After cooling and stretching, the strength, elasticity, transparency and gloss of the fiber are greatly increased. The unusual properties of this polyester make them anticipate that it may have significant commercial value and it is possible to spin the fibers with molten polymers. However, continued studies have shown that obtaining fibers from polyester has only theoretical significance. Because high-polyester melts below 100 °C, it is especially soluble in various organic solvents, but it is only slightly stable in water, so it is not suitable for textiles.
Carotherth then conducted in-depth research on a series of polyester and polyamide compounds. After a number of comparisons, he selected polyamide 66, which was first synthesized from hexamethylenediamine and adipic acid on February 28, 1935 (the first 6 represents the number of carbon atoms in the diamine, and the second 6 represents the amount of diacid in the Carbon atoms). This polyamide is insoluble in common solvents and has a melting point of 263 °C, which is higher than the usual ironing temperature. The drawn fiber has a silky appearance and luster, and is similar in structure and properties to a natural silk, its abrasion resistance and strength. More than any kind of fiber at the time. Considering its properties and manufacturing costs, it is the best choice among known polyamides. DuPont then solved the industrial source problem of producing polyamide 66 raw materials. On October 27th, 1938, it officially announced that the world's first synthetic fiber was born, and named polyamide 66 as nylon (Nylon). . Nylon was later used in English as a generic term for all polyamides that were synthesized from coal, air, water, or other substances, and that have abrasion resistance and flexibility, similar to the chemical structure of proteins.
Nylon 6 and Nylon 66
* Structure: Nylon 6 is polycaprolactam, and Nylon 66 is polyhexamethylene adipate. Nylon 66 is 12% harder than nylon 6, and theoretically, the higher the hardness, the more brittle the fiber and the easier it is to break. However, this slight difference in the use of carpets cannot be differentiated.
* Cleaning and anti-fouling properties: The effect of these two properties is the cross-sectional shape of the fiber and the subsequent anti-fouling treatment. The strength and hardness of the fibers themselves have little effect on cleaning and antifouling properties.
* Melting point and elasticity: The melting point of nylon 6 is 220C and the melting point of nylon 66 is 260C. However, this is not a difference for the temperature conditions of the carpet. The lower melting point makes nylon 6 have better resilience, fatigue resistance and thermal stability than nylon 66.
* Color fastness: Color fastness is not a characteristic of nylon. It is a dye in nylon rather than nylon itself that fades under light.
* Abrasion resistance and dust resistance: A two-and-a-half-year experiment was carried out by Clemson University in the United States with BASF Zeftron500 nylon 6 carpet and DuPont Antron XL nylon 66 carpet respectively at Tampa International Airport. The rug was in a state of high traffic. The results showed that: BASF Zeftron 500 nylon is slightly better than DuPont Antron XL in color retention and pile wear resistance. There is no difference in the dust resistance of the two yarns.
Nylon modification Because nylon has many characteristics, it is widely used in automobiles, electrical equipment, mechanical parts, transportation equipment, textiles, and papermaking machinery.
As the miniaturization of automobiles, the high performance of electrical and electronic equipment, and the lighter weight of mechanical equipment are accelerated, the demand for nylon will be even higher. In particular, nylon, as a structural material, places high demands on its strength, heat resistance, and cold resistance. The inherent disadvantage of nylon is also an important factor limiting its application, especially for the PA6, PA66 two varieties, compared with PA46, PAl2 and other varieties have a strong price advantage, although some properties can not meet the requirements of the relevant industry development. Therefore, it is necessary to expand its application area by modifying and improving certain properties for an application field. Mainly in the following aspects to modify.
1 Improve the water absorption of nylon and improve the dimensional stability of the product.
2 To improve the flame retardancy of nylon to meet the requirements of the electronics, electrical, telecommunications and other industries.
3 Improve the mechanical strength of nylon to achieve the strength of metal materials, replace metal 4 to improve the low temperature resistance of nylon, and enhance its ability to resist environmental strain.
5 to improve the wear resistance of nylon to meet the wear and demand of high occasions.
6 Improve the antistatic properties of nylon to meet the requirements of mines and their mechanical applications.
7 Improve the heat resistance of nylon to meet the requirements of high temperature conditions such as automotive engines.
8 Reduce the cost of nylon and increase product competitiveness.
In short, through the above improvements, the high-performance and functionalization of nylon composite materials is realized, and the development of high-performance, high-quality products in related industries is promoted.
The latest development of modified PA products mentioned earlier that glass fiber reinforced PA was studied in the 1950s, but industrialization was formed in the 1970s. Since 1976, DuPont Co., Ltd We have developed new modified PA products. The United States, Western Europe, Japan, the Netherlands, and Italy have vigorously developed PAs, PAs, PAs, and a large number of modified PAs.
In the 1980s, the development of compatibilizer technology was successful and promoted the development of PA alloys. Countries around the world developed PA/PE, PA/PP, PA/ABS, PA/PC, PA/PBT, PA/PET, PA/ PPO, PA/PPS, PA/I. Thousands of alloys such as CP (liquid crystal polymer) and PA/PA are widely used in industries such as automobiles, motorcycles, electronics, electrical machinery, textiles, sporting goods, office supplies, and home appliance parts.
In the 1990s, new varieties of modified nylons continued to increase. During this period, modified nylons became commercialized, new industries were formed, and they developed rapidly. At the end of the 1990s, the world production of nylon alloys reached 1.1 million tons/year. .
In terms of product development, the company mainly focuses on high-performance nylon PPO/PA6, PPS/PA66, toughened nylon, nano-nylon, and halogen-free flame-retardant nylon; in terms of application, significant progress has been made in the development of automotive parts and electrical components, such as The use of high-flow modified nylon for automotive intake manifolds has been commercialized. The plasticization of this structurally complex component has great significance in terms of applications, and it is more important to extend the life of components and promote the engineering plastics processing technology. development of.
Development Trend of Modified Nylon As the largest and most important product in engineering plastics, Nylon has strong vitality, mainly due to its high performance after modification, followed by automotive, electrical, telecommunications, electronics, and machinery industries. The requirements for high performance are getting stronger. The rapid development of related industries has promoted the progress of high-performance engineering plastics. The future development trend of modified nylon is as follows.
1 The market demand for high-strength and high-rigidity nylon is increasing. New reinforcing materials such as inorganic whisker reinforcement and carbon fiber-reinforced PA will become important varieties, mainly for automotive engine parts, mechanical parts and aviation equipment parts.
2 Nylon alloying will become the mainstream of the development of modified engineering plastics. Nylon alloying is an important way to realize the high performance of nylon, and it is also the main means for manufacturing nylon special materials and improving the performance of nylon. By blending other polymers, the water absorption of nylon is improved, the dimensional stability of the product is improved, and the low-temperature brittleness, heat resistance, and wear resistance are improved. As a result, it is suitable for different types of applications.
The manufacturing technology and application of 3-nanometer nylon will be rapidly developed. The advantage of nano-nylon is that its thermal properties, mechanical properties, flame retardancy, and barrier properties are higher than that of pure nylon, and the manufacturing cost is comparable to that of back-pass nylon. Therefore, it is very competitive.
4 The flame-retardant nylon used in electronics, electrical appliances, and electrical appliances is increasing day by day, and the green flame-retardant nylon is getting more and more attention from the market.
5 Antistatic, conductive nylon and magnetic nylon will become the preferred materials for electronic equipment, mining machinery and textile machinery.
6 The research and application of processing aids will promote the functionalization and high performance of modified nylons.
7 The application of comprehensive technology, the refinement of products is the driving force for the development of its industry.