Major End-Uses

This view of polypropylene, while partially deserved in its early history, has not been true since the early 1980s because of improved polymerization conditions, stabilizers, and pigments. It was recognized that both the chemical inertness that prevents dyeing and the low melting point can be advantageous in many products. 

The melting point of polypropylene is an advantage in many new nonwoven products. Polypropylene fibers can be melted sufficiently to bond to one another without destroying fiber properties. Nonwoven fabrics made from polypropylene can, therefore, be fusion-bonded. 

The thermal stability of polypropylene fabrics at temperatures below melting point (120-135°C) has been improved markedly by the addition of stabilizers. This, along with the inherent stability to a wide variety of chemicals, has allowed both woven and nonwoven polypropylene fabrics to be used in filtration and a wide range of other industrial uses. At temperatures below the melting point, the stability of polypropylene fabrics rivals any but the most expensive high-performance fibers. 

The use of polypropylene fibers will grow depending on the ability of the textile industry to take advantage of properties that can be built into polypropylene. Some of these properties, such as toughness, low density, chemical stability, etc., are inherent to all polypropylene products. Others, like color stability and UV and thermal stability, are built into the product by additives. Still others, such as improved uniformity due to low-temperature extrusion of modified polymers, open new areas of use. The future growth of polypropylene in textiles depends on the ability of the suppliers and users to take advantage of all the properties to make unique products from polypropylene. 

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Acrylics. Acetone is converted via the intermediate acetone cyanohydrin to the monomer methyl methacrylate (MMA) [80-62-6]. The MMA is polymerized to poly(methyl methacrylate) (PMMA) to make the familiar clear acryUc sheet. PMMA is also used in mol ding and extmsion powders. Hydrolysis of acetone cyanohydrin gives methacrylic acid (MAA), a monomer which goes direcdy into acryUc latexes, carboxylated styrene—butadiene polymers, or ethylene—MAA ionomers. As part of the methacrylic stmcture, acetone is found in the following major end use products acryUc sheet mol ding resins, impact modifiers and processing aids, acryUc film, ABS and polyester resin modifiers, surface coatings, acryUc lacquers, emulsion polymers, petroleum chemicals, and various copolymers (see METHACRYLIC ACID AND DERIVATIVES METHACRYLIC POLYMERS). 

Synthetic emulsion polymers account for approximately 70% of the U.S. consumption of acrylate monomers. Major end uses for these latex polymers are coatings (32%), textiles (17%), adhesives (7%), paper (5%), and floor poHshes (3%). The U.S. producers of acryflc copolymer emulsions include Rohm and Haas, Reichhold, National Starch, Union Carbide, Air Products, Unocal, B. F. Goodrich, and H. B. Fuller. 

Solution polymers are the second most important use for acryflc monomers, accounting for about 12% of the monomer consumption. The major end use for these polymers is in coatings, primarily industrial finishes. Other uses of acryflc monomers include graft copolymers, suspension polymers, and radiation curable inks and coatings. 

The major end use of ammonia is the fertilizer field for the production of urea, ammonium nitrate and ammonium phosphate, and sulfate. Anhydrous ammonia could be directly applied to the soil as a fertilizer. Urea is gaining wide acceptance as a slow-acting fertilizer. 

Assuming that only 1% of the -hexane of motor fuels is released to environmental media, such releases could be on the same order of magnitude as the total amount of relatively pure -hexane associated with the major end-uses described in Chapter 4. In addition to emissions to the atmosphere, releases from heating and motor fuel uses to other environmental media are possible as a result of leaks and spills at refineries, pipelines, large tank batteries (or tank farms ), above- and below-ground storage tanks, tanker trucks and railroad tanker cars, or from minor releases at garages or around homes and workplaces. Crude oil spills also result in the release of -hexane to the air or other environmental media. 

On Table I is a list of the major end uses for the new chemicals submitted up through the end of 1981. Intermediates in the manufacture of other chemicals, polymers for a variety of end uses but mainly for paints and coatings, and additives such as flame retardants, plasticizers and antioxidants for plastics account for over half of all the uses of these new chemicals. These seven major categories in total represent slightly over three fourths of all projected uses. One would suspect that this pattern will change with market demand and competitive developments and a year from now we might see intense R D activity in some other specific market areas culminate in the introduction of a line of new chemical substances. 

End uses. Its a little curious that the two major end uses for EG are so different. One is -a consumer product the other is a feedstock for more complicated chemistry. The reasons have to do with two separate properties of EG, one physical property, one chemical property. Because of EG s low freezing point, it is the main ingredient in automotive antifreeze. Because it is so chemically reactive, it is used as a monomer in making polyester polymers and PET, the plastic in the ubiquitous water and drink bottles. 

Developments in monldable particle PP foams are described, nsing the BASF product range as a basis. The monlding process is detailed, physical properties of monldings prodnced from Neopolen P at densities of 20 to 60 kg/cn.m. are detailed and major end-use applications are indicated. The monlding sequence is also illustrated. 

Another important aspect of the ammonia business is seasonality. The major end use for anhydrous ammonia (excluding production of downstream nitrogen products) is as a direct application fertilizer. The application season, particularly in Canada and the northern United States, is limited and significant storage capability is needed. As a result, it is normal to expect a plant to produce a downstream nitrogen product (such as urea) that is 1) easier to store and handle and 2) does not have such a limited application season. Industrial markets are normally nonseasonal57. 

Vinyl acetate is a dear colorless liquid. It has a boiling point of 72 °C and a flash point of -9 °C. In 1977 vinyl acetate production in the United States was 1.60 x 10 pounds (1 ). This gave vinyl acetate a rank of 45 among the 50 top-volume chemicals produced in the United States during 1977. The major end uses of vinyl acetate were adhesives (30 ), paints (20 ), textile finishes (15%), and paper coatings (10 ). Approximately 15 of the vinyl acetate produced was exported (2). 

In the second major use of VAM, PVA is converted to poly(vinyl alcohol) (PVOH) by a transesterification reaction with methanol, giving methyl acetate as coproduct. PVOH finds its major end use in textile sizing and adhesives. Further reaction of PVOH with butyraldehyde or formaldehyde gives polyvinyl butyral (PVB) or polyvinyl formal, which together constitute the third largest consumption of VAM. PVB is used almost exclusively in the adhesive laminating inner layer in safety glass. 

Acrylic fibers are by far the major end use for acrylonitrile. They find use primarily in fabrics for clothing, furniture, draperies, and carpets. The second largest consumer of acrylonitrile is acrylonitrile-butadiene-styrene (ABS) and styrene acrylonitrile (SAN) resins. ABS is useful in industrial and construction applications, and the superior clarity of SAN makes it useful in plastic lenses, windows, and transparent household items. 

Cotton (Figure 1.1) is the most important natural textile fiber, as well as cellulosic textile fiber, in the world, used to produce apparel, home furnishings, and industrial products. Worldwide about 40% of the fiber consumed in 2004 was cotton [1]. (See also Table 9.1 World Production of Textile Fibers on page 130.) Cotton is grown mostly for fiber but it is also a food crop (cottonseed)—the major end uses for cottonseeds are vegetable oil for human consumption whole seed, meal, and hulls for animal feed and linters for batting and chemical cellulose. 

In addition to the various markets for cotton lint, there are also markets for cottonseed and its products [616]. Cottonseed represents about 15-20% of the total value of cotton. Vegetable oil for human consumption, whole cottonseed, meal, hulls for animal feed, and linters for batting and chemical cellulose are the major end uses for cottonseed [616]. 

Industrial processing materials are covered by the following major end uses plastics and elastomers, textiles, agricultural chemicals, leather and paper chemicals, and other miscellaneous uses. 

Approximately 7 billion pounds of eihylene oxide were produced in the United States in 1997, The 1997 selling price was 0.58 a pound, amounting to a commercial value of 4.0 billion. Over 60% of the ethylene oxide produced is used to make ethylene glycoL The major end uses of ethylene oxide are antifreeze (30%), polyester (30%), surfactants (10%), and solvents (5%), We want to calculate the catalyst weight necessary to achieve 60% conversion when ethylene oxide is to be made by the vapor-phase catalytic oxidation of ethylene with air. 

Detailed discussions of the various types of additives used with polyethylene are not appropriate for an introductory text. However, there are many sources for specifics on additives to which the reader is referred (4-11). Excellent discussions are provided in the thorough handbooks edited by Zweifel (4, 5) and a recent text by Fink (6). A more compact overview of additives in film applications (a major end use of polyethylene) is provided by King (7). Specific topics are addressed in several recent trade magazine articles (8-11). 

Major end uses for methanol are for the production of formaldehyde, about 30%, which is used for the preparation of phenol-formaldehyde resins. About 20% is used for the production of methyl -butyl ether, which is used as an additive alone, and in blends with methanol as a fuel component. Further uses are for the esterification of terephthalic, and acrylic acids, and for acetic acid preparation, about 10% each. 

Figure 14.2. Major end uses for wood and bark in the United States, in M or M tonnes, data from Koning and Skog (1987), Waddell et al. (1989), Ulrich (1988) and USDA (1990).

Higher alcohols in the range of C6 to C18 have many industrial applications. Commercial interest includes the whole group of primary and secondary, branched and unbranched, and even- and odd-numbered alcohols. Higher tertiary alcohols are not industrially significant [109]. The C6 to Cn alcohols are called plasticizer alcohols and the C,2 to Cj8 are called surface-active or detergent alcohols because of their respective major end use [109]. Alcohols > C8 are often called fatty alcohols because that was their first original primary source. The world production capacity is currently 3 million ton/yr, of which 88% are synthetic [108,109],... 

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