Polyurethane Polyurethane synthesis

Polyurethane

Polyurethane synthesis, wherein the urethane groups — NH-(C=O)-O- link the molecular units.
A polyurethane (PUR and PU) is polymer composed of a chain of organic units joined by carbamate (urethane) links. Polyurethane polymers are formed by combining two bi- or higher functional monomers. One contains two or more isocyanate functional groups (with formula –N=C=O) and the other contains two or more hydroxyl groups (with formula –OH). The alcohol and the isocyanate groups combine to form a urethane linkage:
ROH + R'NCO → ROC(O)N(H)R' (R and R' are alkyl or aryl groups)
This combining process, sometimes called condensation, typically requires the presence of a catalyst. More complicated monomers are also used.
Polyurethanes are used in the manufacture of flexible, high-resilience foam seating; rigid foam insulation panels; microcellular foam seals and gaskets; durable elastomeric wheels and tires; automotive suspension bushings; electrical potting compounds; high performance adhesives; surface coatings and surface sealants; synthetic fibers (e.g., Spandex); carpet underlay; and hard-plastic parts (i.e., for electronic instruments). Polyurethane is also used for the manufacture of hoses and skateboard wheels as it combines the best properties of both rubber and plastic.
History
The pioneering on polyurethane polymers was conducted by Otto Bayer and his coworkers in 1937 at the laboratories of I.G. Farben in Leverkusen, Germany.[1] They recognized that using the polyaddition principle to produce polyurethanes from liquid diisocyanates and liquid polyether or polyester diols seemed to point to special opportunities, especially when compared to already existing plastics that were made by polymerizing olefins, or by polycondensation. The new monomer combination also circumvented existing patents obtained by Wallace Carothers on polyesters.[2] Initially, work focused on the production of fibres and flexible foams. With development constrained by World War II (when PUs were applied on a limited scale as aircraft coating[2]), it was not until 1952 that polyisocyanates became commercially available. Commercial production of flexible polyurethane foam began in 1954, based on toluene diisocyanate (TDI) and polyester polyols. These materials were also used to produce rigid foams, gum rubber, and elastomers. Linear fibers were produced from hexamethylene diisocyanate (HDI) and 1,4-butanediol (BDO).
The first commercially available polyether polyol, poly(tetramethylene ether) glycol, was introduced by DuPont in 1956 by polymerizing tetrahydrofuran. Less expensive polyalkylene glycols were introduced by BASF and Dow Chemical in 1957. Polyether polyols offered technical and commercial advantages such as low cost, ease of handling, and better hydrolytic stability over polyester polyols and quickly replaced them in the manufacture of polyurethane goods. Other PU pioneers were Union Carbide and Mobay, a U.S. Monsanto/Bayer joint venture.[2] In 1960 more than 45,000 metric tons of flexible polyurethane foams were produced. As the decade progressed, the availability of chlorofluoroalkane blowing agents, inexpensive polyether polyols, and methylene diphenyl diisocyanate (MDI) heralded the development and use of polyurethane rigid foams as high performance insulation materials. Rigid foams based on polymeric MDI (PMDI) offered better thermal stability and combustion characteristics than those based on TDI. In 1967, urethane modified polyisocyanurate rigid foams were introduced, offering even better thermal stability and flammability resistance compared to low-density insulation products. During the 1960s, automotive interior safety components such as instrument and door panels were produced by back-filling thermoplastic skins with semi-rigid foam.
In 1969, Bayer exhibited an all plastic car in Düsseldorf, Germany. Parts of this car were manufactured using a new process called RIM, Reaction Injection Molding. RIM technology uses high pressure impingement of liquid reactive components followed by the rapid flow of the reaction mixture into a mold cavity. Large parts, such as automotive fascia and body panels, can be molded in this manner. Polyurethane RIM evolved into a number of different products and processes. Using diamine chain extenders and trimerization technology gave poly(urethane urea), poly(urethane isocyanurate), and polyurea RIM. The addition of fillers, such as milled glass, mica, and processed mineral fibres gave rise to reinforced RIM (RRIM), which provided improvements in flexural modulus (stiffness), reduction in coefficient of thermal expansion and thermal stability. This technology allowed production of the first plastic-body automobile in the United States, the Pontiac Fiero, in 1983. Further increases in flexural modulus were obtained by incorporating pre-placed glass mats into the RIM mold cavity, also known broadly as resin injection molding (a process technology that also includes thermosetting polyester resins, epoxide resins, etc.) or more specifically for PUR systems as SRIM, or structural RIM.
Starting in the early 1980s, water-blown microcellular flexible foams were used to mold gaskets for panel and radial seal air filters in the automotive industry. Since then, increasing energy prices and the pressures to eliminate PVC plastisol from automotive applications have greatly increased market share. Costlier raw materials are offset by a significant decrease in part weight and in some cases, the elimination of metal end caps and filter housings. Highly filled polyurethane elastomers, and more recently unfilled polyurethane foams are now used in high temperature oil filter applications.
Polyurethane foam (including foam rubber) is often made by adding small amounts of volatile materials, so-called blowing agents, to the reaction mixture. These volatile chemicals yield important performance characteristics, primarily density reduction, cushioning/energy absorption and thermal insulation. In the early 1990s, because of their impact on ozone depletion, the Montreal Protocol led to the greatly reduced use of many chlorine-containing blowing agents, such as trichlorofluoromethane (CFC-11). Other haloalkanes, such as the hydrochlorofluorocarbon 1,1-dichloro-1-fluoroethane (HCFC-141b), were used as interim replacements until their phase out under the Integrated Pollution Prevention and Control (IPPC) directive on greenhouse gases in 1994 and by the Volatile Organic Compounds (VOC) directive of the EU in 1997 (See: Haloalkanes). By the late 1990s, the use of blowing agents such as carbon dioxide, pentane, 1,1,1,2-tetrafluoroethane (HFC-134a) and 1,1,1,3,3-pentafluoropropane (HFC-245fa) became more widespread in North America and the EU, although chlorinated blowing agents remained in use in many developing countries.[3]
Building on existing polyurethane spray coating technology and polyetheramine chemistry, extensive development of two-component polyurea spray elastomers took place in the 1990s. Their fast reactivity and relative insensitivity to moisture make them useful coatings for large surface area projects, such as secondary containment, manhole and tunnel coatings, and tank liners. Excellent adhesion to concrete and steel is obtained with the proper surface treatment and primer. During the same period, new two-component polyurethane and hybrid polyurethane-polyurea elastomer technology was used to enter the marketplace of spray-in-place load bed liners and military marine applications for the U.S. Navy. A one-part polyurethane is specified as high durability deck coatings under MIL-PRF-32171[4] for the US Navy. This technique for coating creates a durable, abrasion resistant composite with the metal substrate, and eliminates corrosion and brittleness associated with drop-in thermoplastic bed liners.
Chemistry
Generalized polyurethane reaction
Polyurethanes are in the class of compounds called reaction polymers, which include epoxies, unsaturated polyesters, and phenolics.[5][6][7][8][9] A urethane linkage is produced by reacting an isocyanate group, -N=C=O with a hydroxyl (alcohol) group, -OH. Polyurethanes are produced by the polyaddition reaction of a polyisocyanate with a polyalcohol (polyol) in the presence of a catalyst and other additives. In this case, a polyisocyanate is a molecule with two or more isocyanate functional groups, R-(N=C=O)n ≥ 2 and a polyol is a molecule with two or more hydroxyl functional groups, R'-(OH)n ≥ 2. The reaction product is a polymer containing the urethane linkage, -RNHCOOR'-. Isocyanates will react with any molecule that contains an active hydrogen. Importantly, isocyanates react with water to form a urea linkage and carbon dioxide gas; they also react with polyetheramines to form polyureas. Commercially, polyurethanes are produced by reacting a liquid isocyanate with a liquid blend of polyols, catalyst, and other additives. These two components are referred to as a polyurethane system, or simply a system. The isocyanate is commonly referred to in North America as the 'A-side' or just the 'iso'. The blend of polyols and other additives is commonly referred to as the 'B-side' or as the 'poly'. This mixture might also be called a 'resin' or 'resin blend'. In Europe the meanings for 'A-side' and 'B-side' are reversed. Resin blend additives may include chain extenders, cross linkers, surfactants, flame retardants, blowing agents, pigments, and fillers.
The first essential component of a polyurethane polymer is the isocyanate. Molecules that contain two isocyanate groups are called diisocyanates. These molecules are also referred to as monomers or monomer units, since they themselves are used to produce polymeric isocyanates that contain three or more isocyanate functional groups. Isocyanates can be classed as aromatic, such as diphenylmethane diisocyanate (MDI) or toluene diisocyanate (TDI); or aliphatic, such as hexamethylene diisocyanate (HDI) or isoph

ผลลัพธ์ (ไทย) 1:

ยูรีเทนแกน การสังเคราะห์โพลียูรี นั้นกลุ่มยูรีเทน — NH-(C=O)-O-ลิงค์หน่วยโมเลกุลPolyurethane (เทนแบบและ PU) เป็นพอลิเมอร์ประกอบด้วยห่วงโซ่เกษตรอินทรีย์หน่วยร่วม โดยเชื่อมโยง carbamate (ยูรีเทน) โพลิเมอร์โพลียูรีได้เกิดขึ้น โดยการรวมสองสองหรือ monomers สูงทำงาน หนึ่งประกอบด้วยอย่าง น้อย 2 กลุ่ม functional isocyanate (ด้วยสูตร – N = C = O) และอื่น ๆ ประกอบด้วยอย่าง น้อย 2 กลุ่มไฮดรอกซิล (มีสูตร – OH) เหล้าและกลุ่ม isocyanate รวมถึงรูปแบบการเชื่อมโยงรีเทน:ROH + R'NCO → ROC (O) N (H) R' (R และ R' เป็นกลุ่ม alkyl หรือ aryl)รวมกระบวนการนี้ บางครั้งเรียกว่ามีหยดน้ำเกาะ ต้องใช้ของเศษ นอกจากนี้ยังใช้ monomers ซับซ้อนมากขึ้นใช้ในการผลิตโฟมยืดหยุ่น มีความ ยืดหยุ่นสูงที่นั่ง ประจำภูมิ ติดตั้งฉนวนกันความร้อนโฟมแข็ง microcellular โฟมซีลและปะเก็น ทนทาน elastomeric ล้อและยาง ระบบกันสะเทือนรถยนต์ bushings ไฟฟ้าสาร potting ประสิทธิภาพสูงกาว ผิวเคลือบและผิว sealants เส้นใยสังเคราะห์ (เช่น นเด็กส์); เสริม และชิ้นส่วนพลาสติกแข็ง (เช่น สำหรับเครื่องมือทางอิเล็กทรอนิกส์) ยูรีเทนแกนยังถูกใช้สำหรับการผลิตท่อและล้อสเก็ตบอร์ดเป็นจะรวมคุณสมบัติดีที่สุดของยางและพลาสติกประวัติThe pioneering on polyurethane polymers was conducted by Otto Bayer and his coworkers in 1937 at the laboratories of I.G. Farben in Leverkusen, Germany.[1] They recognized that using the polyaddition principle to produce polyurethanes from liquid diisocyanates and liquid polyether or polyester diols seemed to point to special opportunities, especially when compared to already existing plastics that were made by polymerizing olefins, or by polycondensation. The new monomer combination also circumvented existing patents obtained by Wallace Carothers on polyesters.[2] Initially, work focused on the production of fibres and flexible foams. With development constrained by World War II (when PUs were applied on a limited scale as aircraft coating[2]), it was not until 1952 that polyisocyanates became commercially available. Commercial production of flexible polyurethane foam began in 1954, based on toluene diisocyanate (TDI) and polyester polyols. These materials were also used to produce rigid foams, gum rubber, and elastomers. Linear fibers were produced from hexamethylene diisocyanate (HDI) and 1,4-butanediol (BDO).The first commercially available polyether polyol, poly(tetramethylene ether) glycol, was introduced by DuPont in 1956 by polymerizing tetrahydrofuran. Less expensive polyalkylene glycols were introduced by BASF and Dow Chemical in 1957. Polyether polyols offered technical and commercial advantages such as low cost, ease of handling, and better hydrolytic stability over polyester polyols and quickly replaced them in the manufacture of polyurethane goods. Other PU pioneers were Union Carbide and Mobay, a U.S. Monsanto/Bayer joint venture.[2] In 1960 more than 45,000 metric tons of flexible polyurethane foams were produced. As the decade progressed, the availability of chlorofluoroalkane blowing agents, inexpensive polyether polyols, and methylene diphenyl diisocyanate (MDI) heralded the development and use of polyurethane rigid foams as high performance insulation materials. Rigid foams based on polymeric MDI (PMDI) offered better thermal stability and combustion characteristics than those based on TDI. In 1967, urethane modified polyisocyanurate rigid foams were introduced, offering even better thermal stability and flammability resistance compared to low-density insulation products. During the 1960s, automotive interior safety components such as instrument and door panels were produced by back-filling thermoplastic skins with semi-rigid foam.In 1969, Bayer exhibited an all plastic car in Düsseldorf, Germany. Parts of this car were manufactured using a new process called RIM, Reaction Injection Molding. RIM technology uses high pressure impingement of liquid reactive components followed by the rapid flow of the reaction mixture into a mold cavity. Large parts, such as automotive fascia and body panels, can be molded in this manner. Polyurethane RIM evolved into a number of different products and processes. Using diamine chain extenders and trimerization technology gave poly(urethane urea), poly(urethane isocyanurate), and polyurea RIM. The addition of fillers, such as milled glass, mica, and processed mineral fibres gave rise to reinforced RIM (RRIM), which provided improvements in flexural modulus (stiffness), reduction in coefficient of thermal expansion and thermal stability. This technology allowed production of the first plastic-body automobile in the United States, the Pontiac Fiero, in 1983. Further increases in flexural modulus were obtained by incorporating pre-placed glass mats into the RIM mold cavity, also known broadly as resin injection molding (a process technology that also includes thermosetting polyester resins, epoxide resins, etc.) or more specifically for PUR systems as SRIM, or structural RIM.Starting in the early 1980s, water-blown microcellular flexible foams were used to mold gaskets for panel and radial seal air filters in the automotive industry. Since then, increasing energy prices and the pressures to eliminate PVC plastisol from automotive applications have greatly increased market share. Costlier raw materials are offset by a significant decrease in part weight and in some cases, the elimination of metal end caps and filter housings. Highly filled polyurethane elastomers, and more recently unfilled polyurethane foams are now used in high temperature oil filter applications.Polyurethane foam (including foam rubber) is often made by adding small amounts of volatile materials, so-called blowing agents, to the reaction mixture. These volatile chemicals yield important performance characteristics, primarily density reduction, cushioning/energy absorption and thermal insulation. In the early 1990s, because of their impact on ozone depletion, the Montreal Protocol led to the greatly reduced use of many chlorine-containing blowing agents, such as trichlorofluoromethane (CFC-11). Other haloalkanes, such as the hydrochlorofluorocarbon 1,1-dichloro-1-fluoroethane (HCFC-141b), were used as interim replacements until their phase out under the Integrated Pollution Prevention and Control (IPPC) directive on greenhouse gases in 1994 and by the Volatile Organic Compounds (VOC) directive of the EU in 1997 (See: Haloalkanes). By the late 1990s, the use of blowing agents such as carbon dioxide, pentane, 1,1,1,2-tetrafluoroethane (HFC-134a) and 1,1,1,3,3-pentafluoropropane (HFC-245fa) became more widespread in North America and the EU, although chlorinated blowing agents remained in use in many developing countries.[3]Building on existing polyurethane spray coating technology and polyetheramine chemistry, extensive development of two-component polyurea spray elastomers took place in the 1990s. Their fast reactivity and relative insensitivity to moisture make them useful coatings for large surface area projects, such as secondary containment, manhole and tunnel coatings, and tank liners. Excellent adhesion to concrete and steel is obtained with the proper surface treatment and primer. During the same period, new two-component polyurethane and hybrid polyurethane-polyurea elastomer technology was used to enter the marketplace of spray-in-place load bed liners and military marine applications for the U.S. Navy. A one-part polyurethane is specified as high durability deck coatings under MIL-PRF-32171[4] for the US Navy. This technique for coating creates a durable, abrasion resistant composite with the metal substrate, and eliminates corrosion and brittleness associated with drop-in thermoplastic bed liners.
Chemistry
Generalized polyurethane reaction
Polyurethanes are in the class of compounds called reaction polymers, which include epoxies, unsaturated polyesters, and phenolics.[5][6][7][8][9] A urethane linkage is produced by reacting an isocyanate group, -N=C=O with a hydroxyl (alcohol) group, -OH. Polyurethanes are produced by the polyaddition reaction of a polyisocyanate with a polyalcohol (polyol) in the presence of a catalyst and other additives. In this case, a polyisocyanate is a molecule with two or more isocyanate functional groups, R-(N=C=O)n ≥ 2 and a polyol is a molecule with two or more hydroxyl functional groups, R'-(OH)n ≥ 2. The reaction product is a polymer containing the urethane linkage, -RNHCOOR'-. Isocyanates will react with any molecule that contains an active hydrogen. Importantly, isocyanates react with water to form a urea linkage and carbon dioxide gas; they also react with polyetheramines to form polyureas. Commercially, polyurethanes are produced by reacting a liquid isocyanate with a liquid blend of polyols, catalyst, and other additives. These two components are referred to as a polyurethane system, or simply a system. The isocyanate is commonly referred to in North America as the 'A-side' or just the 'iso'. The blend of polyols and other additives is commonly referred to as the 'B-side' or as the 'poly'. This mixture might also be called a 'resin' or 'resin blend'. In Europe the meanings for 'A-side' and 'B-side' are reversed. Resin blend additives may include chain extenders, cross linkers, surfactants, flame retardants, blowing agents, pigments, and fillers.
The first essential component of a polyurethane polymer is the isocyanate. Molecules that contain two isocyanate groups are called diisocyanates. These molecules are also referred to as monomers or monomer units, since they themselves are used to produce polymeric isocyanates that contain three or more isocyanate functional groups. Isocyanates can be classed as aromatic, such as diphenylmethane diisocyanate (MDI) or toluene diisocyanate (TDI); or aliphatic, such as hexamethylene diisocyanate (HDI) or isoph

ผลลัพธ์ (ไทย) 3:

การสังเคราะห์ยูรีเทน

ยูรีเทน , ยูรีเทน ซึ่งกลุ่ม - NH - ( C = O ) - O - เชื่อมโยงโมเลกุลหน่วย .
polyurethane ( PUR และ PU ) เป็นพอลิเมอร์ที่ประกอบด้วยโซ่ของหน่วยอินทรีย์เข้าร่วมโดยเมต ( ยูรีเทน ) การเชื่อมโยง ยูรีเทนพอลิเมอร์ที่เกิดขึ้นโดยการรวมสองบี - หรือสูงกว่าการทำงานแบบ .หนึ่งประกอบด้วยสองคนหรือมากกว่าทำให้หมู่ฟังก์ชัน ( พร้อมสูตร ( n = C = O ) และอื่น ๆประกอบด้วยสองคนหรือมากกว่ากลุ่มไฮดรอกซิล ( พร้อมสูตร ( โอ้ ) แอลกอฮอล์ และทำให้กลุ่มรวมแบบยูรีเทน การเชื่อมโยง :
ต้า r'nco → keyboard - key - name : ( O ) N ( H ) R ( ' R และ R ' แอลคิลหรือกลุ่มกลืนกัน )
นี้รวมกระบวนการ บางครั้งเรียกว่าการควบแน่น โดยปกติจะต้องมีตัวเร่งแบบซับซ้อนมากขึ้นนอกจากนี้ยังใช้
( ใช้ในการผลิตโฟมยืดหยุ่นความยืดหยุ่นสูง , ที่นั่ง ; แผงฉนวนโฟมแข็ง โฟม microcellular ; ซีลและปะเก็นยางทนทาน ; ล้อ ยาง บูชช่วงล่าง ยานยนต์ ไฟฟ้า และกระถาง กาวที่ประสิทธิภาพสูง และวัสดุเคลือบผิวพื้นผิว ; เส้นใยสังเคราะห์ ( เช่น spandex ) ;หนุนพรม และชิ้นส่วนพลาสติกแข็ง ( เช่นสำหรับเครื่องมืออิเล็กทรอนิกส์ ) ยูรีเทนนอกจากนี้ยังใช้สำหรับการผลิตท่อและล้อสเก็ตบอร์ด มันรวมคุณสมบัติที่ดีที่สุดของทั้งยางและพลาสติก

ยูรีเทนพอลิเมอร์ในประวัติศาสตร์การสำรวจดำเนินการโดย Otto Bayer และเพื่อนร่วมงานของเขาใน 1937 ที่ห้องปฏิบัติการของขนาด farben ใน Leverkusen เยอรมนี[ 1 ] ที่พวกเขาได้รับการยอมรับว่าใช้ polyaddition หลักการผลิตจากไดไอโซไซยาเนต ( ของเหลวและของเหลว polyether หรือโพลีเอสเตอร์ diols ดูเหมือนจะชี้โอกาสพิเศษ โดยเฉพาะเมื่อเทียบกับที่มีอยู่แล้วที่ถูกสร้างโดย polymerizing พลาสติกส์ หรือ polycondensation .การรวมกันของโมโนเมอร์ใหม่ยังหลีกเลี่ยงได้โดยวอลเลซ คาโรเทอร์สิทธิบัตรที่มีอยู่ในส่วน [ 2 ] ตอนแรก งานเน้นการผลิตเส้นใย และโฟมที่ยืดหยุ่น กับการพัฒนาอย่างต่อเนื่อง โดยสงครามโลกครั้งที่สอง ( เมื่อใช้ในระดับที่จำกัดหนองเป็นเครื่องบินเคลือบ [ 2 ] ) , มันไม่ได้จนกว่าปี 1952 ที่ polyisocyanates กลายเป็นที่สามารถใช้ได้ในเชิงพาณิชย์การผลิตโฟมมีความยืดหยุ่นเชิงพาณิชย์เริ่มขึ้นในปี 1954 จากโทลูอีนไดไอโซไซยาเนต ( TDI ) และ Polyester Polyols . วัสดุเหล่านี้ถูกใช้เพื่อผลิตแข็งโฟม , ยาง , เหงือกและอีลาสโตเมอร์ . ใยเส้นผลิตจากเฮกซะเมทิลีนไดไอโซไซยาเนต ( HDI ) และ 1,4-butanediol ( BDO )
1 โพลีออล polyether อาด พอลิอีเทอร์ไกลคอล , tetramethylene )ได้รับการแนะนำโดย Dupont ในปี 1956 โดย polymerizing เตตระไฮโดรฟแรน . ไกลคอล polyalkylene ไม่แพงถูกแนะนำโดย BASF และ ดาว เคมิคอล ใน 1957 polyether Polyols เสนอข้อได้เปรียบทางเทคนิคและเชิงพาณิชย์ เช่น ต้นทุนต่ำ ความง่ายในการจัดการ และย่อยสลายโพลีเอสเตอร์เสถียรภาพดีกว่ากว่าเกาะได้อย่างรวดเร็วและแทนที่พวกเขาในการผลิต polyurethane สินค้า