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أخوانى الاعزاء انا مهندس اتصالات ولا افهم كثيرا فى الكمياء ولكنى محتاج ضرورى لتركيبه ومكونات الفيبر جلاس وكذلك البولى أستر ضرورى جدا ومن أين اشترى المكونات من مصر جازكم الله خيرا
السلام عليكم ورحمه الله وبركات
Glass fiber is formed when thin strands of silica-based or other formulation glass is extruded into many fibers with small diameters suitable for textile processing. Glass, even as a fiber, has little crystalline structure (see amorphous solid). The properties of the structure of glass in its softened stage are very much like its properties when spun into fiber. One definition of glass is “an inorganic substance in a condition which is continuous with, and analogous to the liquid state of that substance, but which, as a result of a reversible change in viscosity during cooling, has attained so high a degree of viscosity as to be for all practical purposes rigid.”[1]
The technique of heating and drawing glass into fine fibers has been known for millennia; however, the use of these fibers for textile applications is more recent. The first commercial production of fiberglass was in 1936. In 1938, Owens-Illinois Glass Company and Corning Glass Works joined to form the Owens-Corning Fiberglas Corporation. Until this time all fiberglass had been manufactured as staple. When the two companies joined together to produce and promote fiberglass, they introduced continuous filament glass fibers.[1] Owens-Corning is still the major fiberglass producer in the market today.
[ Chemistry
The basis of textile-grade glass fibers is silica, SiO2. In its pure form it exists as a polymer, (SiO2)n. It has no true melting point but softens up to 2000°C, where it starts to degrade. At 1713°C, most of the molecules can move about freely. If the glass is then cooled quickly, they will be unable to form an ordered structure.[2] In the polymer it forms SiO4 groups which are configured as a tetrahedron with the silicon atom at the center, and four oxygen atoms at the corners. These atoms then form a network bonded at the corners by sharing the oxygen atoms.
The vitreous and crystalline states of silica (glass and quartz) have similar energy levels on a molecular basis, also implying that the glassy form is extremely stable. In order to induce crystallization, it must be heated to temperatures above 1200°C for long periods of time.[1]
Molecular Structure of Glass
Although pure silica is a perfectly viable glass and glass fiber, it must be worked with at very high temperatures which is a drawback unless its specific chemical properties are needed. It is usual to introduce impurities into the glass in the form of other materials, to lower its working temperature. These materials also impart various other properties to the glass which may be beneficial in different applications. The first type of glass used for fiber was soda lime glass or A glass. It was not very resistant to alkali. A new type, E-glass was formed that is alkali free (< 2%) and is an alumino-borosilicate glass.[3] This was the first glass formulation used for continuous filament formation. E-glass still makes up most of the fiberglass production in the world. Its particular components may differ slightly in percentage, but must fall within a specific range. The letter E is used because it was originally for electrical applications. S-glass is a high strength formulation for use when tensile strength is the most important property. C-glass was developed to resist attack from chemicals, mostly acids which destroy E-glass.[3] T-glass is a North American variant of C-glass. A-glass is an industry term for cullet glass, often bottles, made into fiber. AR-glass is alkali resistant glass. Most glass fibers have limited solubility in water but it is very dependent on pH. Chloride ions will also attack and dissolve E-glass surfaces. A recent trend in the industry is to reduce or eliminate the boron content in the glass fibers.
Since E-glass does not really melt but soften, the softening point is defined as “the temperature at which a 0.55 – 0.77 mm diameter fiber 235 mm long, elongates under its own weight at 1 mm/min when suspended vertically and heated at the rate of 5°C per minute”.[4] The strain point is reached when the glass has a viscosity of 1014.5 poise. The annealing point, which is the temperature where the internal stresses are reduced to an acceptable commercial limit in 15 minutes, is marked by a viscosity of 1013 poise.[4]
[ Properties
Glass fibers are useful because of their high ratio of surface area to weight. However, the increased surface area makes them much more susceptible to chemical attack.
By trapping air within them, blocks of glass fiber make good thermal insulation, with a thermal conductivity of 0.05 W/m-K.
Glass strengths are usually tested and reported for “virgin” fibers: those which have just been manufactured. The freshest, thinnest fibers are the strongest because the thinner fibers are more ductile. The more the surface is scratched, the less the resulting tenacity.[3] Because glass has an amorphous structure, its properties are the same along the fiber and across the fiber.[2] Humidity is an important factor in the tensile strength. Moisture is easily adsorbed, and can worsen microscopic cracks and surface defects, and lessen tenacity.
In contrast to carbon fiber, glass can undergo more elongation before it breaks.[2] There is a correlation between bending diameter of the filament and the filament diameter. See KH Hillermeier, 1973, Freudenstadt. The viscosity of the molten glass is very important for manufacturing success. During drawing (pulling of the glass to reduce fiber circumference) the viscosity should be relatively low. If it is too high the fiber will break during drawing, however if it is too low the glass will form droplets rather than drawing out into fiber.
[ Manufacturing processes
[] Melting
There are two main types of glass fiber manufacture and two main types of glass fiber product. First, fiber is made either from a direct melt process or a marble remelt process. Both start with the raw materials in solid form. The materials are mixed together and melted in a furnace. Then, for the marble process, the molten material is sheared and rolled into marbles which are cooled and packaged. The marbles are taken to the fiber manufacturing facility where they are inserted into a can and remelted. The molten glass is extruded to the bushing to be formed into fiber. In the direct melt process, the molten glass in the furnace goes right to the bushing for formation.[4]
[ Formation
The bushing plate is the most important part of the machinery. This is a small metal furnace containing nozzles for the fiber to be formed through. It is almost always made of platinum alloyed with rhodium for durability. Platinum is used because the glass melt has a natural affinity for wetting it. When bushings were first used they were 100% platinum and the glass wetted the bushing so easily it ran under the plate after exiting the nozzle and accumulated on the underside. Also, due to its cost and the tendency to wear, the platinum was alloyed with rhodium. In the direct melt process, the bushing serves as a collector for the molten glass. It is heated slightly to keep the glass at the correct temperature for fiber formation. In the marble melt process, the bushing acts more like a furnace as it melts more of the material.[1]
The bushings are what make the capital investment in fiber glass production expensive. The nozzle design is also critical. The number of nozzles ranges from 200 to 4000 in multiples of 200. The important part of the nozzle in continuous filament manufacture is the thickness of its walls in the exit region. It was found that inserting a counterbore here reduced wetting. Today, the nozzles are designed to have a minimum thickness at the exit. The reason for this is that as glass flows through the nozzle it forms a drop which is suspended from the end. As it falls, it leaves a thread attached by the meniscus to the nozzle as long as the viscosity is in the correct range for fiber formation. The smaller the annular ring of the nozzle or the thinner the wall at exit, the faster the drop will form and fall away, and the lower its tendency to wet the vertical part of the nozzle.[1] The surface tension of the glass is what influences the formation of the meniscus. For E-glass it should be around 400 mN per m.[3]
The attenuation (drawing) speed is important in the nozzle design. Although slowing this speed down can make coarser fiber, it is uneconomic to run at speeds for which the nozzles were not designed.[1]
Some basics
poly ester
To get an idea about coverage, importance and complexity of the polyester industry, some basic information about polyester or polyethylene terephthalate (PET) at first:
What is polyester? Polyester is a synthetic polymer made of purified terephthalic acid (PTA) or its dimethyl ester dimethyl terephthalate (DMT) and monoethylene glycol (MEG). It ranges after polyethylene and polypropylene at the third place in terms of market size.
The main raw materials are described as follows:
[ul]
[li]Purified Terephthalic Acid – PTA – CAS-No.: 100-21-0[/li][/ul]Synonym: 1,4 Dibenzenedicarboxylic acid,Sum formula; C6H4(COOH)2 , mol weight: 166,13
[ul]
[li]Dimethylterephthalate – DMT- CAS-No: 120-61-6[/li][/ul]Synonym: 1,4 Dibenzenedicarboxylic acid dimethyl esterSum formula C6H4(COOCH3)2 , mol weight: 194,19
[ul]
[li]Mono Ethylene Glycol – MEG – CAS No.: 107-21-1[/li][/ul]Synonym: 1,2 EthanediolSum formula: C2H6O2 , mol weight: 62,07More information about polyester raw materials one can find for PTA [1],DMT [2] and MEG [3], at the webpage INCHEM “Chemical Safety Information from Intergovernmental Organizations”.
To make finally a polymer of high molecular weight one needs a catalyst. The most common catalyst is antimony trioxide (or antimony tri acetate)
Antimony trioxide – ATO – CAS-No.: 1309-64-4 Synonym: non, mol weight: 291,51 Sum formula: Sb2O3
In 2008 about 10 000 t Sb2O3 are used to produce around 49 Mio t polyethylene terephthalate.
Polyester is described as follows:
Polyethylene Terephthalate CAS-No.: 25038-59-9 Synonym / abbreviations: polyester, PET, PES Sum Formula: H-[C10H8O4]-n=60-120 OH, mol unit weight: 192,17
What are the success factors of the unbroken capacity growth of polyethylene terephthalate?
[ul]
[li]The relatively easy accessible raw materials PTA or DMT and MEG[/li][li]The very well understood and described simple chemical process of polyester synthesis[/li][li]The low toxicity level of all raw materials and side products during production and processing[/li][li]The possibility to produce PET in a closed loop at low emissions to the environment[/li][li]The outstanding mechanical and chemical properties of polyester[/li][li]The recycle ability[/li][li]The wide variety of intermediate and final products made of polyester[/li][/ul]All these facts are making this polymer one of the key elements of our daily life.
In table 1 we see the estimated world polyester production for textile polyester, bottle polyester resin, film polyester mainly for packaging and specialty polyesters for engineering plastics, which are the main fields of application. According to this table, the world’s total polyester production might exceed 50 million tons per annum before the year 2010.
Table 1: World polyester production
Market size per yearProduct Type2002 [Mio t/a]2008 [Mio t/a]Textile-PET2039Resin, Bottle/A-PET916Film-PET1.21.5Special Polyester12.5TOTAL31.249
With its production volume and product diversity, polyester ranges after polyethylene (33.5%), polypropylene (19,5%) with a market share of about 18% in third position among all plastic materials produced worldwide.
The polyester production chain, and the relative polyester industry chain, will now be explained in greater detail and step by step.
[edit] Raw material producer
The raw materials PTA, DMT and MEG are mainly produced by large chemical companies which are sometimes integrated down to the crude oil refinery where p-xylene is the base material to produce PTA and liquefied petroleum gas (LPG) is the base material to produce MEG.
Large PTA producers are for instance BP, Reliance, Sinopec, SK-Chemicals, Mitsui and Eastman Chemicals. MEG production is in the hand of about 10 global players which are headed by MEGlobal a JV of DOW and PIC Kuweit followed by Sabic.
Let us assume the average production capacity of a single polyester plant is about 200 t/day: we are talking about nearly 500 polyester plants around the globe. Adding to this figure the continuously-growing polyester recycling industry, which is estimated to have processed about 3 million t polyester waste in 2007 alone (5 million T/a in 2010 estimated) and where each plant produces on average about 10 000 t/a, we have another 500 plants. This is 1000 polyester production plants, all needing specific and polyester-dedicated engineering and equipment, machinery, process technology and know-how, producing, processing and recycling polyester.
Among the world’s largest polyester producers are the following companies:
Artenius, Advansa, DAK, DuPont, Eastman/Voridian, Hyosung, Huvis, Indorama, Invista, Jiangsu Sanfangxian, M&G Group, Mitsui, Mitsubishi, NanYa Plastics,Reichhold, Reliance, Rongsheng, Sabic, Teijin, Toray, Tonkun, Tuntex, Wellman, Yizheng Sinopec and Sanfanxiang.
One should notice that China’s capacity to produce and process polyester in more than 500 plants is nearly half that of the world’s polyester capacity meanwhile. More information about polyester in China can be found under the web site of China Chemical Fiber Economic Information Network [4].
[edit] Polyester processing
After the first stage of polymer production in the melt phase, the product stream divides into two different application areas which are mainly textile applications and packaging applications. In figure 2 the main applications of textile and packaging polyester are listed.
Table 2: Textile and packaging polyester application list
POLYESTER-BASED POLYMER (MELT or PELLETS)TextilePackagingStaple fiber (PSF)Bottles for CSD, Water, Beer, Juice, DetergentsFilaments POY, DTY, FDYA-PET FilmTechnical yarn and tire cordThermoformingNon-woven and spunbondBO-PET Biaxial oriented FilmMono-filamentStrapping
Abbreviations: PSF = Polyester Staple Fiber; POY = Partially Oriented Yarn; DTY = Draw Textured Yarn; FDY = Fully Drawn Yarn; CSD = Carbonated Soft Drink; A-PET = Amorphous Polyester Film; BO-PET = Biaxial Oriented Polyester Film;
A comparable small market segment (<< 1 million t/a) of polyester is used to produce engineering plastics and masterbatch.
In order to produce the polyester melt with a high efficiency, high-output processing steps like staple fiber (50–300 t/d per spinning line) or POY /FDY (up to 600 t/d split into about 10 spinning machines) are meanwhile more and more horizontal, integrated, direct processes. This means the polymer melt is directly converted into the textile fibers or filaments without the common step of pelletizing. We are talking about full horizontal integration when polyester is produced at one site starting from crude oil or distillation products in the chain oil -> benzene -> PX -> PTA -> PET melt -> fiber / filament or bottle-grade resin. Such integrated processes are meanwhile established in more or less interrupted processes at one production site. Eastman Chemicals introduced at first the idea to close the chain from PX to PET resin with their so-called INTEGREX® process. The capacity of such horizontal, integrated productions sites is >1000 t/d and can easily reach 2500 t/d.
Besides the above mentioned large processing units to produce staple fiber or yarns, there are ten thousands of small and very small processing plants, so that one can estimate that polyester is processed and recycled in more than 10 000 plants around the globe. This is without counting all the companies involved in the supply industry, beginning with engineering and processing machines and ending with special additives, stabilizers and colors. This is a gigantic industry complex and it is still growing by 4–8% per annum, depending on the world region. Useful information about the polyester industry can be found under [5] where a “Who is Producing What in the Polyester Industry” is gradually being developed.
[edit] Synthesis
Synthesis of polyesters is generally achieved by a polycondensation reaction. See “condensation reactions in polymer chemistry”. The General equation for the reaction of a diol with a diacid is : (n+1) R(OH)2 + n R´(COOH)2 —> HO[ROOCR´COO]nROH + 2n H2O
[edit] Azeotrope esterification
In this classical method, an alcohol and a carboxylic acid react to form a carboxylic ester. To assemble a polymer, the water formed by the reaction must be continually removed by azeotrope distillation.
[edit] Alcoholic transesterification
See main article on transesterification.
O \ C - OCH3 + OH[Oligomer2] /[Oligomer1]
O \ C - O[Oligomer2] + CH3OH /[Oligomer1](ester-terminated oligomer + alcohol-terminated oligomer) (larger oligomer + methanol)
[edit] Acylation (HCl method)
The acid begins as an acid chloride, and thus the polycondensation proceeds with emission of hydrochloric acid (HCl) instead of water. This method can be carried out in solution or as an enamel.
Silyl methodIn this variant of the HCl method, the carboxylic acid chloride is converted with the trimethyl silyl ether of the alcohol component and production of trimethyl silyl chloride is obtained
[edit] Acetate method (esterification)
Silyl acetate method
[edit] Ring-opening polymerization
Aliphatic polyesters can be assembled from lactones under very mild conditions, catalyzed anionically, cationically or metallorganically.
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