Poly(vinyl chloride) (PVC) (CAS: 9002-86-2)
Poly(vinyl chloride), commonly abbreviated PVC, is the third-most widely produced polymer, after polyethylene andpolypropylene.
PVC comes in two basic forms: rigid (sometimes abbreviated as RPVC) and flexible. The rigid form of PVC is used inconstruction for pipe, and in profile applications such as doors and windows. It is also used for bottles and other non-food packaging, and cards (such as bank or membership cards). It can be made softer and more flexible by the addition ofplasticizers, the most widely used being phthalates. In this form, it is also used in plumbing, electrical cable insulation, imitation leather, signage, inflatable products and many applications where it replaces rubber.
Pure poly(vinyl chloride) is a white, brittle solid. It is insoluble in alcohol, but slightly soluble intetrahydrofuran.
PVC's relatively low cost, biological and chemical resistance and workability have resulted in it being used for a wide variety of applications. It is used for sewerage pipes and other pipe applications where cost or vulnerability to corrosionlimit the use of metal. With the addition of impact modifiers and stabilizers, it has become a popular material for windowand door frames. By adding plasticizers, it can become flexible enough to be used in cabling applications as a wireinsulator. It has been used in many other applications. PVC demand is likely to increase at an average annual rate of 3.9% over the next years.
Roughly half of the world's polyvinyl chloride resin manufactured annually is used for producing pipes for municipal and industrial applications. In the water distribution market it accounts for 66% of the market in the US, and in sanitary sewer pipe applications, it accounts for 75%. Its light weight, low cost, and low maintenance make it attractive. However, it must be carefully installed and bedded to ensure longitudinal cracking and overbelling does not occur. Additionally, PVC pipes can be fused together using various solvent cements, or heat-fused (butt-fusion process, similar to joining HDPE pipe), creating permanent joints that are virtually impervious to leakage.
In February, 2007 the California Building Standards Code was updated to approve the use of chlorinated polyvinyl chloride(CPVC) pipe for use in residential water supply piping systems. CPVC has been a nationally accepted material in the US since 1982; California, however, has permitted only limited use since 2001. The Department of Housing and Community Development prepared and certified an environmental impact statement resulting in a recommendation that the Commission adopt and approve the use of CPVC. The Commission's vote was unanimous and CPVC has been placed in the 2007 California Plumbing Code.
In the United States and Canada, PVC pipes account for the largest majority of pipe materials used in buried municipal applications for drinking waterdistribution and wastewater mains. Buried PVC pipes in both water and sanitary sewer applications that are 4 inches (100 mm) in diameter and larger are typically joined by means of a gasket-sealed joint. The most common type of gasket utilized in North America is a metal reinforced elastomer, commonly referred to as a Rieber sealing system.
PVC is commonly used as the insulation on electrical cables; PVC used for this purpose needs to be plasticized.
In a fire, PVC-coated wires can form hydrogen chloride fumes; the chlorine serves to scavenge free radicals and is the source of the material's fire retardance. While HCl fumes can also pose a health hazard in their own right, HCl dissolves in moisture and breaks down onto surfaces, particularly in areas where the air is cool enough to breathe, and is not available for inhalation. Frequently in applications where smoke is a major hazard (notably in tunnels and communal areas) PVC-free cable insulation is preferred, such as low smoke zero halogen (LSZH) insulation.
Unplasticized poly(vinyl chloride) (uPVC) for construction
uPVC, also known as rigid PVC, is extensively used in the building industry as a low-maintenance material, particularly inIreland, the United Kingdom, and in the United States. In the USA it is known as vinyl, or vinyl siding. The material comes in a range of colors and finishes, including a photo-effect wood finish, and is used as a substitute for painted wood, mostly for window frames and sills when installing double glazing in new buildings, or to replace older single-glazed windows. Other uses include fascia, and siding or weatherboarding. This material has almost entirely replaced the use ofcast iron for plumbing and drainage, being used for waste pipes, drainpipes, gutters and downspouts. uPVC does not contain phthalates, since those are only added to flexible PVC, nor does it contain BPA. uPVC is known as having strong resistance against chemicals, sunlight, and oxidation from water.
Poly(vinyl chloride) is formed in flat sheets in a variety of thicknesses and colors. As flat sheets, PVC is often expanded to create voids in the interior of the material, providing additional thickness without additional weight and minimal extra cost (see Closed-cell PVC foamboard). Sheets are cut using saw and rotary cutting equipment. Plasticized PVC is also used to produce thin, colored, or clear, adhesive-backed films referred to simply as vinyl. These films are typically cut on acomputer-controlled plotter or printed in a wide-format printer. These sheets and films are used to produce a wide variety of commercial signage products and markings on vehicles, e.g. car body stripes.
Clothing and furniture
PVC has become widely used in clothing, to either create a leather-like material or at times simply for the effect of PVC.PVC clothing is common in Goth, Punk, clothing fetish and alternative fashions. PVC is less expensive than rubber, leather, and latex which it is therefore used to simulate.
PVC fabric is water-resistant so is used in coats, skiing equipment, shoes, jackets, aprons, and bags.
The two main application areas for single use medically approved PVC compounds are flexible containers and tubing: containers used for blood and blood components for urine or for ostomy products and tubing used for blood taking and blood giving sets, catheters, heart-lung bypass sets, hemodialysis sets etc. In Europe the consumption of PVC for medical devices is approximately 85.000 tons every year. Almost one third of plastic based medical devices are made from PVC. The reasons for using flexible PVC in these applications for over 50 years are numerous and based on cost effectiveness linked to transparency, light weight, softness, tear strength, kink resistance, suitability for sterilization and biocompatibility.
DEHP (Di-2ethylhexylphthalate) has been medically approved for many years for use in such medical devices; the PVC-DEHP combination proving to be very suitable for making blood bags because DEHP stabilises red blood cells, minimising haemolysis (red blood cell rupture). However, DEHP is coming under increasing pressure in Europe. The assessment of potential risks related to phthalates, and in particular the use of DEHP in PVC medical devices, was subject to scientific and policy review by the European Union authorities, and on 21 March 2010, a specific labelling requirement was introduced across the EU for all devices containing phthalates that are classified as CMR (carcinogenic, mutagenic or toxic to reproduction). The label aims to enable healthcare professionals to use this equipment safely, and, where needed, take appropriate precautionary measures for patients at risk of over-exposure.
DEHP alternatives, which are gradually replacing it, are Adipates, Butyryltrihexylcitrate (BTHC), Cyclohexane-1,2-dicarboxylic acid, diisononylester (DINCH), Di(2-ethylhexyl)terephthalate, polymerics and trimellitic acid, 2-ethylhexylester (TOTM).
Flexible PVC flooring is inexpensive and used in a variety of buildings covering the home, hospitals, offices, schools, etc. Complex and 3D designs are possible due to the prints that can be created which are then protected by a clear wear layer. A middle vinyl foam layer also gives a comfortable and safe feel. The smooth, tough surface of the upper wear layer prevents the buildup of dirt, which prevents microbes from breeding in areas that need to be kept sterile, such as hospitals and clinics.
The handles of the VictorinoxSwiss Army knives are made of PVC.
PVC has been used for a host of consumer products of relatively smaller volume compared to the industrial and commercial applications described above. Another of its earliest mass-market consumer applications was to make vinyl records. More recent examples include wallcovering, greenhouses, home playgrounds, foam and other toys, custom truck toppers (tarpaulins), ceiling tiles and other kinds of interior cladding.
Due to PVC piping being cheaper than metals used in musical instrument making, it is a common alternative when making instruments, often for leisure or for rarer instruments such as the contrabass flute.