Polyvinyl chloride commercial production

Simply by changing the components added to polyvinyl chloride, we can create a wide range of properties. The receptiveness of the resin to different additives, the many processing methods available to producing polyvinyl chloride-based products, and its low cost combine to make it one of the most versatile polymers in commercial use today. 

The properties of a polymer depend not only on its gross chemical composition but also on its molecular weight distribution, copolymer composition distribution, branch length distribution, and so on. The same monomer(s) can be converted to widely differing polymers depending on the polymerization mechanism and reactor type. This is an example of product by process, and no single product is best for all applications. Thus, there are several commercial varieties each of polyethylene, polystyrene, and polyvinyl chloride that are made by distinctly different processes. 

Examples of important commercial products obtained by free radical polymerisation of substituted ethenes are polypropene (polypropylene). Polyphenylethene (polystyrene), poly-1 chloroethene (polyvinyl chloride) and poly 1-methoxy carbonyl-1 methylethene (polymethalmethacrylate). 

A vast number of polymer compounds are available commercially. Generally they are known by their polymer type in full or abbreviated (e.g., acrylic, polyvinyl chloride or PVC, high density polyethylene or HDPE), and frequently by a manufacturer s trade name. There is little standardisation into classes based on chemical composition or physical performance, as there is for metals. In reality, a particular chemical composition does not fully define the physical properties, while each class of performance properties can be met by a range of competing polymer types. The current trend is towards further diversification polymer compounds are increasingly being tailored to a particular application. Only in industries where recycling is an issue is there pressure for a more limited number of polymers, which can be identified and separated at the end of product life. 

In addition to the polymer, copolymers of vinyl chloride with other vinyl monomers are important commercial plastics. Copolymers with vinyl acetate, which is produced from acetylene and acetic acid, are widely used in sheeting, surface coating, and filaments, being less brittle and more readily soluble in organic solvents than is pure polyvinyl chloride. Copolymers with acrylonitrile are also of importance for the production of... 

C. PVC (Polyvinyl chloride) filler used in the production of inert loaded cord (Type III) shall be of standard commercial grade and quality... 

In spite of Baekeland s success, it was another two decades before the Age of Polymers can really be said to have been born. The 1920s and 1930s saw the invention and/or commercialization of a number of new polymeric products ("plastics") that most consumers now consider to he essential chemicals in their lives. These products include the urea formaldehyde plastics (1923), polyvinyl chloride (PVC 1926), polystyrene (1929), nylon (1930), polymethylmethacrylate (acrylics 1931), polyethylene (1933), the melamine plastics (1933), polyvinylidene chloride (Saran 1933), polyvinyl acetate (PVA 1937), and tetrafluoroethylene (Teflon 1938). 

As the shear rate increases, the viscosity of some dispersions actually increases. This is called dilatancy, or shear-thickening. Dilatancy can be due to the dense packing of particles in very concentrated dispersions for which at low shear, the particles can just move past each other but at high shear they become wedged together such that the fluid cannot fill (lubricate) the increased void volume, and the viscosity increases. An example of this effect is the apparent drying of wet beach sand when walked on, the sand in the footprint initially appears very dry and then moistens a few seconds later. Other examples include concentrated suspensions (plastisols) of polyvinyl chloride (PVC) particles in plasticizer liquid and the commercial novelty product Silly Putty (which is a silicone material). 

One of the advantages of protein electrophoresis is that much of the equipment can be fashioned using materials which are readily available from hardware and electronics stores at considerable savings over many of the products offered by laboratory supply companies. For example, gel molds, grinding trays, and buffer trays can be made out of polyvinyl chloride (PVC) board or acrylic materials available from local distributors. Most laboratories use a combination of custom-made and commercial equipment. 

Polyvinyl Chloride. (Table 15.5) this is the most versatile of the commercial thermoplastic polymers. It is used mainly for rigid and flexible plastics, for rubberlike products, for coatings on steel, cloth, and paper, and in smaller amounts for specialty fibers. It is processed mainly by extrusion and calendering, and in smaller amounts by injection, compression, and... 

The composition of feed polymers also has an important effect on the properties of products. In the experimental work of Miskolczi et al. commercial waste plastics from the packaging, electronic and automotive industry and the agriculture were used as raw materials. The samples contained high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), ethylene-propylene copolymer (EPC), polystyrene (PS), polyamide 6.6 (PA 6.6) and polyvinyl chloride (PVC). 

We learned much from nature with these early attempts to produce useful polymer products based on modified, or reconstituted ( semisynthetic ) natural polymers, and many of these processes are still in use today. The first of the purely synthetic commercial polymers came with the small-scale introduction of Bakelite in 1907. This phenol-formaldehyde resin product was developed by Leon Baekeland. It rapidly became a commercial reality with the formation of The General Bakelite Company by Baekeland, and construction of a larger plant at Perth Amboy, New Jersey, in 1910. At about this time styrene was being combined with dienes in the early commercialization of processes to produce synthetic rubber. Polystyrene itself was not a commercial product in Germany until 1930 and in the U.S.A. in 1937. The only other purely synthetic polymers that made a commercial appearance during this early development period were polyvinyl chloride and polyvinyl acetate, both in the early 1920s. 

Chlorine is used to produce many commercially important products. Tremendous amounts of it are used in extractive metallurgy and in chlorinating hydrocarbons to produce a variety of compounds (such as polyvinyl chloride, a plastic). Chlorine is present as CI2, NaClO, Ca(C10)2, or Ca(C10)Cl in household bleaches as well as in bleaches for wood pulp and textiles. Under carefully controlled conditions, CI2 is used to kill bacteria in public water supplies. 

The timing of the petroleum companies entry into the chemical industry determined their long-term position in the industry. The four that commercialized petrochemicals before the Japanese attack on Pearl Harbor— Standard Oil of New Jersey (Exxon by 1993), Shell, Standard Oil of California (Chevron by 1993), and Phillips—were the first movers. By the 1950s they had become the leaders in the basic feedstocks and commodity polymers such as polystyrene, polyvinyl chloride, polyethylene, and polypropylene. Those companies that entered after 1941 achieved success by focusing on specific niche products in the manner of the smaller U.S. companies. As shown in Table 1.1, these include Arco (Atlantic Refining Company), Amoco (Standard Oil of Indiana), Ashland, and BP America (acquirer of Standard Oil of Ohio). 

Following the war, Solvay expanded its output in its European factories and built new ones in Italy, Greece, and other countries. It maintained ties with all its earlier allies except, of course, with Russia, where its properties had been confiscated. Before World War I, however, it had done little to commercialize new chemicals through process technologies, as Dow had done in the United States. But it did move into polymer/petrochemicals quickly after World War II. In 1949 Solvay initiated the production of polyvinyl chloride, becoming a European leader in that basic polymer commodity. The company then entered into the production of HDPB in 1959 and PP in 1966. Shortly thereafter, it began to produce a variety of end-products in the manner of the American companies for use in both consumer and industrial chemical lines. In 1974 Solvay returned to the U.S. markets, setting up headquarters in Deer Park, Texas. By that time its soda ash and caustic soda processes had become obsolete.3 ... 

Electrochemical processes provide the basis for numerous chemical industries that are important both in the dollar value of the product, as in the case of aluminum, and in the value of the derived products. For example, chlorine, a large-volume chemical, is an essential intermediate in the production of polyvinyl chloride plastics, a 5 billion industry. The sizes of individual industries (3,4) are indicated in Tables 3-1 and 3-2. The large contributors are the more mature industries that are on a plateau of their growth curves. Research and development in those mature industries can have significant dollar value, and the commercial basis for R D funding already exists. 

The commercial and household products containing polyvinyl chloride are generally regarded as posing no threat to human health. However, a number of questions have been raised about possible health hazards and risks to the environment as a result of the process by which polyvinyl chloride is made, some of its applications, and its eventually disposal. For example, polyvinyl chloride is made from vinyl chloride, which itself is toxic and a carcinogen. People who work with vinyl chloride in production facilities are at risk for developing a form of liver cancer that may be related to exposure to vinyl chloride. Vinyl chloride, in turn, is made from chloride, a very toxic gas that poses health risks to people who work with it. 

Vinyl chloride was first discovered in the early 1800s. It was made from the reaction of dichloroethane and alcoholic potash. Later it was discovered that vinyl chloride polymerized spontaneously on prolonged exposure to sunlight, and studies of the white solid product, polyvinyl chloride, were carried out and published in 1872. In 1912, a commercial process for vinyl chloride produced from acetylene and hydrochloric acid with a mercuric chloride catalyst was patented in Germany and assigned to Chem-ische Fabrik Griesheim-Electron. By 1930, vinyl chloride was being produced as a commercial product based on this process 117,18]. 

I won t dwell on the implications of all this, but I will mention that Barbara didn t get her chemistry right. The original Barbie dolls were made not of polyethylene but of polyvinyl chloride, or PVC. When this plastic was made commercially available in 1942, it became the basis of a whole slew of vinyl products. The problem with pvc is that it is extremely britde. In order to give it flexibility, manufacturers mix it with substances that can account for as much as 70 percent of the product s total weight. At one point, plasticizers such as dibutyl phthalate were used to separate the long polymer chains of pvc, allowing them to slide over one another, making the plastic pliable. 

Although the possible number of polymers is theoretically limitless, the economics of their production and processing, as well as the physical and chemical properties they have, restrict the number of commercial importance to a few dozen (see Fig. 2.2), and in packaging applications the number of polymers used is even smaller. The polymers most commonly used in packaging are polyolefins, specifically polyethylene and polypropylene. Polystyrene, polyvinyl chloride, and polyethylene terephthalate (PET) are also among the most commonly used packaging polymers. 

---