13 March 2013
Latex Paint Raw Materials: A Global Web
Paint is everywhere. People paint walls, floors, furniture, fences, products, and more; and to a designer, paint is a vital tool for color, texture, and protection of surfaces. If paint is so important and commonly used, why do most know so little about it? The majority of people know very little about their products – how they work and where they come from – and products have much more to them than people realize. Sure, someone might know that her paint is latex, but does she know what else that product is made of, and what the components that make the paint are made of, and where the elements that make up the components of the paint come from? She probably does not know, and she also does not care or have time to figure it out. Products such as paint have become so complex that even after hours of research, one may not be able to find all of this information about them, and people cannot spent days researching every product in order to make educated purchases. After narrowing the product of paint down to only white latex paints used in interiors, the raw materials are still a part of a global web of extraction and production that could not be completely uncovered for the purposes of this paper. However, the web of information has been unraveled enough to discover the most important materials of white latex paint primarily used in interiors and where they come from.
The basic secondary materials of paint include the solvent, resin, pigment, extenders, and additives. The solvent is the liquid that carries the solid components of the paint and evaporates after application to leave a solid dry film on the surface. The solvent basically determines whether the paint is latex or oil-based, with latex having a mostly water solvent and oil-based having a mineral spirits solvent. The resin, also known as the binder, is the main component of the solid dry film left after the solvent evaporates. The resin must stick to the surface, bind to the pigment, and have the physical properties necessary for the intended surface such as gloss, abrasion resistance, hardness, and flexibility. The pigment determines the paint’s color and opacity and can be organic or inorganic. Since there are a variety of pigments, this paper will focus on the most common pigment, titanium dioxide, which is inorganic and helps create white paint. The solvent, resin, and pigment are essential materials for the creation of paint.
Though extenders and additives vary and are not always required, they are still an important aspect of paint production. Since adding pigments can drive the cost of production up, extenders are added to bring it down. Extenders have a similar refractive index to the resin and can affect the gloss of the paint. They are chosen from a long list of ground minerals, with some of the more popular choices being calcium carbonate, silica, clay, talc, and feldspar. Additives are used in small amounts to improve various properties of the paint or fix deficiencies in the paint. Some additives are consistently mixed in during production, while others are mixed in after a problem has been found. For how small of a percentage they contribute to the paint, there are a wide variety of additives such as wetting/dispersing agents, anti-marring agents, and biocides (“Paint”, “What is Paint”). The primary materials of additives or extenders will not be investigated because there are so many types of them and they are not used consistently. Since the solvent, resin, and pigment are consistently used and vital to creating paint, it is important to know their primary materials and have a sense of where they come from.
One might think that latex paints simply use water as a solvent, but glycol and a coalescent aid are also involved. Each of these materials serves their own purpose and is created in different ways. Ethylene or propylene glycol is used as antifreeze and to help with wet-edge retention, which is “the ability to allow all the water to evaporate before the latex particles fuse into a continuous film” (“Paint”). Though they serve the same purpose, ethylene and propylene glycols have some major differences. Ethylene glycol is created through the combination of water and ethylene oxide, and it is the simplest glycol. Ethylene glycol and diethylene glycol manufacturing are currently dependent on each other, and large amounts of water are used to separate ethylene oxide from other glycols. Chemicals of the propylene glycol family are manufactured as co-products and consist of monopropylene glycol (PG), dipropylene glycol (DPG), and tripropylene glycol (TPG). The process and materials used to create propylene glycol are more complex than that of ethylene glycol:
All commercial production [of propylene glycol] is via the hydrolysis of propylene oxide [… which] is manufactured by either the chlorohydrin process or peroxidation (coproduct) process. In the chlorohydrin process, chlorine, propylene, and water are combined to make propylene chlorohydrin, which then reacts with inorganic base to yield the oxide. The peroxidation process converts either isobutane or ethylbenzene directly to an alkyl hydroperoxide, which then reacts with propylene to make propylene oxide, and t-butyl alcohol or methylbenzyl alcohol, respectively. (“Glycols”)
Clearly, the glycols have their own list of primary materials used for their creation, but these chemicals and processes are not simply explained without prior knowledge on the subject.
The glycols and water have an important role as part of the solvent, but the coalescent aid is equally important. After the paint is applied and the water and glycol portion of the solvent evaporate, the coalescent aid allows the latex beads of the resin to flow together and then eventually evaporates like the rest of the solvent. Coalescent aid is usually a volatile plasticizer, but more information on its manufacturing and what it is made of is not readily available (“Paint”). The primary materials in the solvent of latex paint include water, ethylene or propylene glycols, and coalescent aid, plus all of the chemicals used to create the glycols and coalescent aid. Even more chemicals are probably used to create the chemicals used in the glycols and coalescent aid! For what seems to be the simplest secondary material in latex paint, the solvent has a great deal going into it.
The solvent may be necessary for any paint, but the resin is the most important aspect and determines many of the paint’s properties. There are a variety of resins for paint depending on what the paint will be used for, but the most common types of latex resins for indoor painting are vinyl/vinyl acetate-based or acrylates. The vinyl coatings are not very hydraulically stable, so they are typically used as interior flat paints in areas such as living rooms, bedrooms, or on ceilings. To create vinyl resin, “vinyl acetate and either n-butyl acrylate or 2-ethylhexyl acrylate are copolymerized” (“Paint”). A variety of methods and materials have been used to polymerize vinyl acetate, but “the dominant method of production in North America is by the reaction of ethylene with acetic acid and oxygen in the presence of palladium catalyst,” which is much faster and can be performed more easily on a large scale than the other popular method of using emulsion (“Vinyl Acetate Polymers”). The other materials in vinyl acetate based resin, n-butyl acrylate and 2-ethylhexyl acrylate, are also polymers, but information on their production is not readily available or comprehensible to those unfamiliar with chemistry. The same goes for the various acrylate monomers used to create the other type of resin used in interiors, acrylate. The acrylate is more hydraulically stable than the vinyl resin, so it is used more in areas such as bathrooms and kitchens (“Paint”). Processing the materials for latex paint resins is done on a very complex chemical level and has a drastic impact on how the paint performs and can be used.
The last secondary material that is vital to the creation of latex paint is the pigment. Of course there are a variety of organic and inorganic pigments used to create different colors, so focusing on the most popular pigment, titanium dioxide used for white, should provide a sufficient understanding of the raw materials and processes going into pigments. Even after narrowing it down to just white paint, the pigment aspect seems to require the most primary materials and assortment of processes. Since titanium dioxide is used so frequently, it has many producers worldwide – fifty to be exact, with DuPont suppliers in the lead. Titanium dioxide can be found in the crystal forms of rutile, anatase, and brookite, but brookite is not used because it does not have good pigmentary properties like rutile and anatase. There are six raw minerals most commonly used for the production of titanium dioxide, including rutile and anatase. According to the Kirk-Othmer Encyclopedia of Chemical Technology, “Since titanium is the seventh most common metallic element in the earth’s crust, [these] titanium minerals are plentiful in Nature” (“Pigments, Inorganic”). Even with such a high amount of titanium in nature, “approximately 95% of titanium is consumed in the form of titanium dioxide (TiO2),” which is used in a variety of products besides paint (“Titanium: Statistics and Information”). In addition to those minerals used in production, the titanium dioxide pigment particles are coated with various agents to prevent the chalking of the white paints. Overall, titanium dioxide uses many materials in production that have their own sources and systems.
The six raw minerals most commonly used in production of titanium dioxide are all a part of the pigment’s primary materials. The minerals used include rutile, anatase, ilmenite, leucoxene, titanium slag, and synthetic rutile; but according to the USGS rutile, ilmenite, and leucoxene are the only ones with significant economic purposes (“Pigments, Inorganic”, “Titanium: Statistics and Information”). Still, it is important to explore where each of these minerals come from. Most rutile “comes from the beach sands of Australia, Florida, India, Brazil, and South Africa; [and] the total worldwide supply is estimated to be ∼50 million metric tons, with about a half million tons mined a year” (“Pigments, Inorganic”). Not much information is available for anatase other than that it is found as a crystal like rutile and is used for titanium. The lack of information may be because it is not one of the minerals with significant economic purposes. Ilmenite is even more plentiful than rutile and is estimated to meet the demands of the paint industry for the next 150 years. “At this time ∼9 million metric tons of ilmenite is mined annually,” with “the largest sources […] in Australia, Canada, South Africa, Russia, and the United States” (“Pigments, Inorganic”). Ilemenite weathers into leucoxene over time, so it is safe to assume that leucoxene also fairly abundant and mined around the same areas. These more popular minerals, aside from anatase, seem to require comparatively minimal processes for extraction.
Titanium slag and synthetic rutile seem to have more complicated extraction and production processes that require more materials than the other, more popular, minerals. Titanium slag is created through “a metallurgical process during which iron is removed from ilmenite by reduction with coke in an electric arc furnace at 1200–1600◦C. Under these conditions, iron oxide is reduced to metal, melts, and separates from the formed titanium slag.” “Synthetic rutile raw material is produced from ilmenite by reducing its iron oxides and leaching out the metallic iron with hydrochloric or sulfuric acids” (“Pigments, Inorganic). What seems to be extra processing for titanium slag and synthetic rutile might explain why they are less popular to use, especially since they both are derived from ilmenite, which is already used in a more simple way to extract titanium dioxide. There seems to be a broad range of minerals used for the production of titanium dioxide, but more must still be accounted for when considering the production of a usable white pigment.
Titanium dioxide can create chalking in the white paint, so it needs to be coated with extra minerals. These coupling agents “improve filler-polymer adhesion leading to increased strength” (DeArmitt). The most common coupling agents used to coat titanium dioxide particles are silicon, aluminum, and zirconium (“Pigments, Inorganic”). One source also claims titanium is a used for this purpose, but since the titanium dioxide is created from titanium, it is unapparent how adding more titanium would improve filler-polymer adhesion and prevent chalking. Silicon itself is “a light chemical element that combines with oxygen and other elements to form silicates,” but silicon ferroalloys and silicon metal are produced from silica as quartz or quartzite (“Silicon: Statistics and Information”). Various sources seem to show that silicates and silica are the same thing, but this could be incorrect. It is unclear whether pure silicon or silicon ferroalloys or silicon metal is used in paint. The origins of aluminum are clearer than that of silicon. Aluminum is derived from the ore, bauxite, which is imported to the U.S. primarily form Jamaica and Guinea (“Aluminum Beverage Can”). Zirconium has an interesting connection to the mining of minerals used to create titanium dioxide, as explained by the USGS: “The principal economic source of zirconium is the zirconium silicate mineral, zircon (ZrSiO4).
Zircon is a coproduct or byproduct of the mining and processing of heavy-mineral sands for the titanium minerals, ilmenite and rutile, or tin minerals” (“Zirconium and Hafnium”). Since ilmenite and rutile are two of the more common minerals used for the creation of titanium dioxide, it seems to be most convenient and efficient to use zirconium to coat the titanium dioxide because all of the elements could be mined at the same time. Without these various minerals, the pigment would not function properly and could ruin the paint.
While there are many raw materials in white latex paint used for interiors, identifying the secondary materials as the solvent, resin, and pigment, and the primary materials that go into these, provides a reasonable understanding of the raw materials of this paint. Not every material identified has an explanation of how it is made or where it comes from, either due to lack of importance in comparison to other identified materials or lack of information and understanding. The solvent’s basic primary materials include water, ethylene or propylene glycol, and coalescent aid. Two types of resins are used for interior paint, including vinyl resin composed of vinyl acetate and n-butyl acrylate or z-ethylhexyl acrylate, and acrylates resin composed of various acrylate monomers. Finally, white pigments are made from titanium dioxide, which can be found in various minerals and is then coated with coupling agents to prevent chalking. Extenders and Additives are also important secondary materials to paint, but an extensive variety of these exist all with different primary materials that could not be briefly identified. When analyzing the entire life cycle of paint, one must understand that these identified raw materials are simply for the production of the paint itself. Many other raw materials are used over the span of paint’s lifetime, such as in the can, equipment used in production, transportation, use, and waste management. If so many materials are used in just the initial processing of the paint, one can only imagine the amount used when considering the entire lifecycle. It is understandable for people to assume that they do not have time to discover their products’ life cycle analysis on their own, but it is important for people to realize that with every product purchased or every design decision made, they are investing in that product’s materials, energy use, and waste as well as the impact that those materials and processes can have.
“Aluminum Beverage Can.” How Products are Made. Advameg, 2013. Web. 23 February 2013.
DeArmitt, Chris. “Coupling Agents.” Cray Valley: Hydrocarbon Specialty Chemicals. Total. Web. 23 February 2013.
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“Paint.” Kirk-Othmer Encyclopedia of Chemical Technology. Van De Mark, M. R., Sandefur, K. D. and Durham, K. A. Vol. 17. 23 September 2005. Wiley Online Library. Web. 16 February 2013.
“Pigments, Inorganic.” Kirk-Othmer Encyclopedia of Chemical Technology. Swiler, D.R. 19 August 2005. 1- . Wiley Online Library. Web. 17 February 2013.
“Silicon: Statistics and Information.” USGS. USA.gov, 15 February 2013. Web. 23 February 2013.
“Titanium: Statistics and Information.” USGS. USA.gov, 6 February 2013. Web. 23 February 2013.
“Vinyl Acetate Polymers.” Kirk-Othmer Encyclopedia of Chemical Technology. Cordeiro, C. F. and Petrocelli, F. P. 14 January 2005. Wiley Online Library. Web. 16 February 2013.
“What is Paint.” painterforum.com. painterforum.com, 2010. Web. 14 February 2013.
“Zirconium and Hafnium: Statistics and Information.” USGS. USA.gov, 8 February 2013. Web. 23 February 2013.
Prof. Christina Cogdell
Latex Paint - Embodied Energy
Embodied energy is the total amount of energy required to produce a certain product through a process. This energy calculation is very important in order to weigh the total amount of input that will be incorporated in the production of a certain product. The embodied energy incorporates all the energy that a production process entails from the extraction of the materials, the processing and other components included until it is finished. The embodied energy is not the internal energy of the of the materials that incorporates the material. It includes both the direct and the indirect energies that are involved (Thompson, J W, and Kim Sorvig, 230).
In the case of manufacturing a particular product, the embroided energy involved will include the the energy required in the extraction of a material, the transportation of the raw materials, the distribution of the product, the re-use, the maintainance, the recycling and waste management. All these processes require a form of energy in their production and hence the calculation of the total energy will be of importance in the determination of the product final value.
The embroided energy calculation is also very vital in the determination of the impact of a product use to the environment. This is the carbon content that is released to the environment which may destroy the ozone layer. This information will be useful in the consideration of proper methods that can be employed to make the product safe for the environment. This is the requirement of current regulations that require the production of the products with less carbon emission.
Embodied Energy in the Production of Latex Paint
In this case the, calculation of the embodied energy includes the calculation of the embodied energy of all the components that make up the the paint. The latex paint has several components that include the pigments, binder and solution. This paint can also be recycled which gives a very good option in terms of the the embodied energy. The many firms are now opting to the recycling of the latex paint in order to cut on costs and develop environmentally friendly paints in terms of the reduction of volatile organic compounds (VOC).
Latex paint is also called emulsion paint in some parts. This kind of paint was first developed with its binder being the resins from the rubber tree. This is the origin of the name of the paint, latex. A resin is a secretion from plants that contain several chemicals such as hydrocarbons. The resins collected from the tree were used to make the first binder to be used in the latex based paint. However, nowadays the binders that are used to make the latex based paint are usually synthetic, that is, they no longer come from the latex tree although the name is maintained.
The calculation of the embodied energy of this pain will require the consideration of the total energy of extraction, transport, maintenance, manufacturing and recycling. The making of a product requires more raw materials than the output then some will go to waste. This waste material has also to be considered in the calculation of the total embodied energy (Thompson, J W, and Kim Sorvig, 230)
The binder is therefore the most important element of the paint because it will determine the quality of the paint. Some of the components that are used as the binders are styrene and epoxy. The most widely used one is the vinyl acrylic latex. One type of acrylic called the elastomer is used. This type of acrylic gives this kind of paints a special feature that makes it elastic and therefore not prone to breakages or is not brittle as compared to the oil paints. The term acrylic in this context means latex that is synthetic.
There are two commonly used chemicals that make the binders in order to give them their different properties in terms of stickiness, the size of particles, and the leveling or even hardness. These chemicals are 100% acrylic and vinyl acrylic. 100% acrylic binder is the most superior of the two and some of the desirable properties are:
i. It has a higher tendency of adhesion under wet conditions and this enables it to develop a high resistance to such factors as to blister, crack or even to peel. This will make them to be long lasting. This is because the coatings that have been made are very strong and cannot be easily damaged.
ii. It also has a very high resistance to water and therefore reduces the tendency to blister, collect dirt or even get mild. This ensures that the paints will stay in their bright state for longer periods of time and also will not require cleaning from time to time.
This type is mostly preferred for painting the exterior of the building because of the water resistance property that makes them last longer. Although the 100% acrylic binder has very many desirable characteristics, it is also expensive. A tradeoff is to be made between the price and the properties. Vinyl acrylic can be used in the interior use where water is not a major concern.
The values of the embodied energy of the components of the bonding element is taken to be latex. There are two types of latex that are available to be used. The natural latex and the synthetic latex. In the making of the current range of paints, the synthetic paint is mostly used in the manufacturing of the binder. The embodied energy as is given by the inventory and carbon energy table (ICE) shows that this type of latex has a high embodied energy. For natural latex, the embodied energy is shown to be 67.6MJ/Kg while that of synthetic rubber is 120 MJ/Kg. These results show the total embodied energy considering all the factors such as the extraction cost, transport and manufacture of the product. This is shown by the extract of the table of Inventory Carbon and Energy below (Cross, Rob, and Roger Spencer, 309).
Another component that makes up the paint is the solvent which in our case is water. Water does not need processing and the embodied energy is obtained from the Inventory Carbon and Energy table as shown in the extract below:
The table shows that the embodied energy of water is very small. The embodied energy is given to be 0.20 MJ/Kg. This is very small and gives the latex paint a edge over the oil based paints which hane a higher embodied energy and releases an high amount of Volatile organic compounds to the environment.
Embodied energy of recycled paint
Recycling of the latex paint has in the recent past been advocated for because it gives better result in terms of the embodied energy(Kibert, Charles J, 294). The embodied energy of recycled paint is a third of the virgin paint. This is so because the various processes that involve the extraction of material will not be repeated. Some of the advantages of recycled latex paint are:
i. It reduces the amout of landfill of paint that have ot been used. This is an environmental factor that is very desirable in that it reduces the filling of dumpsites hence conservation of the environment.
ii. The recycling of paint reduces the manufacture of virgin paint this is the paint that is being manufactured fron cratch and hence use an imence amount of energy from the extraction of raw materials to the processing (Kibert, Charles J, 294)
iii. The Volatile Organic Compounds that is contained in the recycled pain is small as compared to the virgin paint that has been manufactured.
iv. Recycled paint is also cheap to manufacture and therefore it will be cheap in the market price.
Water based paints have in the recent year been advocated to be used by many constructors and government agencies. These paints offer some superior advantages as compared to the oil based paints (Litchfield 96). Some of the advantages include:
i. These paints do not easily crack or blister easily because of the component called elasticin that is contained in the binder. This component allows for expansion and contraction of the film with the changes in temperature and therefore cannot easily break. This advantage makes the paints to be appealing and long lasting.
ii. Latex paints take a very short time to dry. This is very important in those crowded places such as schools where paintwork can easily be destroyed if it stays wet for long.
iii. Latex paints have pores at the surface; these pores will enable the dry wall to ‘breathe’. This breathing reduces the development of mild environments in walls.
iv. It is cheaper to use latex paints because of the advantage that the walls do not develop cracks and blisters easily and therefore reduces the time it takes for repainting to be done. The other reason is that, the solvent to be used for the paint is water, which is cheaply and readily available.
v. Latex paints do not have the strong smell that contain the volatile organic compounds (VOC) that causes harm to the environment and also may cause sickness to people. The effects of these VOCs are to destroy the ozone layer or cause come illnesses to individuals.
vi. These types of paints are not flammable and therefore reduce the risk of a building catching and spreading fire.
vii. The rollers and the brushes that are used for painting purposes can easily be cleaned using soap and water as compared to the oil based paint where special chemicals such as turpentine are used.
The paint industry has been developing and changing over the years giving better qualities of paints with the gradual reduction in volatile organic compounds. The embodied energy of the latex paint depends on whether synthetic latex or the natural one is used. It also depend on whether the virgin compounds are used or whether it is recycled. Recycled paint is therefore the best option.
Cross, Rob, and Roger Spencer. Sustainable Gardens. Collingwood, Vic: Csiro, 2009. Internet resource.
Hammond, Geoff, and Craig Jones. Inventory of Carbon & Energy: Ice. Bath Avon, U.K.: Sustainable Energy Research Team, Department of Mechanical Engineering, University of Bath, 2008. Internet resource.
Kibert, Charles J. Sustainable Construction: Green Building Design and Delivery. Hoboken, N.J: John Wiley & Sons, 2008. Print
Nayak, Ganesh, and Kumar, Vinayak. Product Life Cycle Assessment. Jotun Paints, UAE: Jotun Abu Dhabi LLC.
Quinn, Jim. Recycled Paint and Green Building: VOC’s and Other Issues. Portland, OR: Metro, Print. n.d.
Sustainable Homes: Embodied Energy in Residential Property Development : a Guide for Registered Social Landlords. Teddington: Hastoe Housing Association, 1999. Print.
Thompson, J W, and Kim Sorvig. Sustainable Landscape Construction: A Guide to Green Building Outdoors. Washington: Island Press, 2008. Print.
Wastes and Emissions of Latex Paint
Looking around in my apartment, every wall, door and ceiling in each room is painted white. White is the most common color to paint the inside of your home with. However, does it ever occur to you what chemicals are used in the entire process and what wastes and emissions are released? White latex paint has many wastes and emissions that are released into the atmosphere that can have affects on both humans and the environment.
The raw materials in latex paint contain many emissions. There are a large number of different chemicals used to make latex paint, but the main ones are propylene, vinyl acetate, propylene oxide, propylene glycol, acrylate, titanium dioxide and aluminum.
Propylene is one of the very beginning chemicals used in the process. It is a gas or vapor that reduces the percent of oxygen in the air in a confined area. If inhaled large amounts, it can result in headaches, dizziness, and nausea in humans. The exposure of this chemical to workers is very limited in the workplace due to meeting the operating standards, thus resulting in low chances of getting released into the atmosphere (Nova Chemicals, 2010). If it is emitted, this is due to the process flares storage and handling operation and fugitive emission from process equipment. Air emissions can contribute to photochemical formation of ground level ozone and possible smog formation (Nova Chemicals, 2010).
Furthermore, vinyl acetate is the next major raw material used to make latex paint. In addition, it is a main component to the vinyl acetate based resin. It is considered a federal hazardous air pollutant and a toxic air contaminant (Scorecard.goodguide.com). This chemical is colorless, flammable, and a liquid that has a sweet smell. Vinyl acetate is released in the environment by industrial emissions; when released in the atmosphere, it is degraded rapidly by reaction with photochemically produced hydroxyl radicals (Florida Spectrum). It is an odorless thermoplastic formed by the polymerization of vinyl acetate (Answers, 2013). It is soluble in other chemicals such as ethane, acetone and chloroform. In the light, the liquid forms into a colorless compound with a transparent mass. When exposed to humans and when vinyl acetate is a gas in the atmosphere, it has some effects on humans when exposed. It can cause severe irritation to the eyes, throat and respiratory tract; however, massive exposure in industrial places can cause chronic bronchitis with other symptoms (Scorecard.goodguide.com). There is no information on whether it causes cancer on humans.
Equally important is the raw material propylene oxide. The chlorohydrin process produces this chemical. It is a colorless liquid epoxide compound that exists at room temperature with an odor of ethereal benzene (National Taxicology Program, 2011). The emission of propylene oxide into the atmosphere occurs through evaporation through vents in latex paint production, handling, storage, transport, and use, which is the most important source of pollution in the atmosphere (World Health Organization, 1985). Propylene oxide liquid wastes can be removed from the air by scrubbing. The emissions from the liquid waste can be controlled by incineration (World Health Organization, 1985).
Not only is propylene oxide a major component to latex paint, however propylene glycol is also. It is used as reinforced plastic laminates for marine construction, gel coats, sheet molding compounds and synthetic marble castings (Dow, 2013). It is a vapor in the atmosphere that is released from manufacturing companies. Propylene glycol can be removed from the atmosphere by wet deposition. It undergoes rapid photochemical oxidation via reaction with hydroxyl radicals with a half-life of 20 hours in the atmosphere (Propylene Glycol).
In the same fashion as the other raw materials, titanium dioxide is also one of the main chemicals used in the production of latex paint. Titanium dioxide is one of the two components that make up the pigments for latex paint. It is the most commonly used white pigments because of its whiteness. Since it is used so often, the emission rate is high. The titanium slag production electric furnaces, the synthetic rutile production using the Becher process, and the rutile titanium dioxide production via the chloride route are the cause of emissions. (Jubb, 2006). If the titanium dioxide dust is inhaled, it can cause cancer to humans according to the International Agency for Research on Cancer (Wikipedia, 2013). Workers can be exposed to titanium dioxide in industries during packing, milling, site cleaning and maintenance (Wikipedia, 2013).
Equally important in the production of the pigments as titanium dioxide is aluminum. When being produced, it not only uses a lot of energy, but also creates a vast amount of carbon dioxide. Emissions from carbon dioxide accounts for 50% of total direct carbon dioxide, which has equivalent emissions from aluminum production (Harrison, 2009). Aluminum production emits the largest amount of tetrafluoromethane and hexafluoroethane. Air emissions occur from primary aluminum production during the reduction of aluminum oxide to aluminum metal in the pot room (Harrison, 2009). Hydrogen fluoride and fluorocarbons are produced from the electrolysis of the bauxite that is dissolved in cryolite. Also, workers in the pot room have developed asthma. As carbon anodes are consumed, fluorocarbons and other gases like carbon dioxide are emitted and contribute to aluminum smelter environmental emissions (Harrison, 2009). Fluoride emissions are released while making aluminum scrap because aluminum fluoride is substituted for chlorine to remove impurities from the molten metal. Air emissions occur by the production of grinding of bauxite (Harrison, 2009).
Latex paint manufacturing companies also release emissions. The most common emissions are the volatile organic compounds (VOC’s) that evaporate during the manufacturing process (Emission Inventory Prevention Program, 2005). Besides VOC’s, particulate matter emissions can also occur from handling the solid powders that are used in manufacturing the paint. The air emissions that occur are from process operations, related miscellaneous operations, material storage, equipment leaks and spill and other abnormalities. In the process operations, the emissions come from mixing, grinding, blending and filling activities (Emission Inventory Prevention Program, 2005). Emissions can occur in the process operations while loading the material. VOC’s emissions can be released during the material loading of mixing and grinding equipment because of the displacement of organic vapors (Emission Inventory Prevention Program, 2005). According to the Emission Inventory Prevention Program, if the device is uncovered or the lid is open, the mixing tank can emit VOC’s. Depending on the grinding equipment, VOC’s can come about from the chute through which ingredients are added. Also, particulate matter emissions can be released when materials are being loaded from handling pigments and other solids (Emission Inventory Prevention Program, 2005).
In the first place, emissions can be released due to increased heat in manufacturing companies. In high-speed dispensers, ball and pebble mills and in other dispersing equipment, the temperature rises as some of the kinetic mixing energy is converted to thermal energy. The Emission Inventory Prevention Program states that since the temperature rose, it is controlled through the use of the cold water jacket on the process vessel. The vapor in the headspace expands as the VOC’s in the mixer heat up, thus causing solvent emissions from the equipment to be released (Emission Inventory Prevention Program, 2005). The emissions are able to escape the equipment through loose fittings or duct connections, which then enter the air in the room; they are considered fugitive emissions.
Additionally, VOC’s can be emitted by surface evaporation. This can happen during mixing, dispersing and blending operations if the vessel contents are exposed to the atmosphere. Depending on the types of mixing and grinding in the paint production, emissions can be released through agitator shaft openings or around the edges of a vessel lid (Emission Inventory Prevention Program, 2005).
Furthermore, emissions can be released during miscellaneous operations such as solvent reclamation. This means during the purification of dirty or spent solvent going through a distillation device (Emission Inventory Prevention Program, 2005). By loading the solvent into the distillation equipment, the operation of the distillation equipment and spillage can cause VOC emissions to be released. The loading and spilling releases VOC’s that are considered fugitive; however, emissions from the operation of the equipment are generally discharged through a condenser vent and are considered point source (Emission Inventory Prevention Program, 2005).
Not to mention, during the cleaning process, emissions can also be released. The process equipment can be cleaned with solvent as many times as needed, such as after each batch. But, VOC’s can occur from charging the mixer or dispenser with solvent, which those emissions can be considered fugitive. From the process equipment, washing the solvents in cold cleaner or an open-top vapor degreaser can clean the small items; the cold cleaner is the most common out of the two (Emission Inventory Prevention Program, 2005). From this type of cleaning, the VOC’s are classified as fugitive. Another way to clean is the wastewater treatment. This system treats contaminated water that is generated during the process; it has a series of surface impoundments that are used for equalization, neutralization, aeration and clarification of the waste stream (Emission Inventory Prevention Program, 2005). The VOC’s that are released from each type of basin can also be considered fugitive.
Also, in the manufacturing process, there are various types of storage tanks that release emissions that are used to store solvents and resins to make the paint. The tanks have a fixed-roof design; the emissions that are released from these tanks are breathing and working losses (Emission Inventory Prevention Program, 2005). The Emission Inventory Prevention Program states that breathing loss is the expulsion of vapor from a tank through vapor expansion and contraction that changes the ambient temperatures and barometric pressures. This loss happens without the level of the liquid in the tank changing. Working loss can be defined as the combination of loss from the filling and emptying of the tanks. Evaporation during the filling operations causes an increase in the liquid level in the tank. As this level increases, the pressure inside the tank maximizes the relief pressure and vapors are expelled from the tank. When emptying occurs, evaporative emissions occur when air is drawn into the tank when removing the liquid; it becomes saturated with organic vapor and expands causing the vapor to be released in the vapor relief valve (Emission Inventory Prevention Program, 2005). Since the VOC’s are released through a vent, the emissions are considered as a point source.
In like matter, emissions can be released if there are leaks in the equipment. Equipment such as pipes, pumps, valves, and flanges are used to transport stored materials from the storage tanks to the paint manufacturing operation. Leaks can develop over time in the pipes and supporting hardware as liquid material is pumped from the storage tanks to the specific process area (Emission Inventory Prevention Program, 2005). VOC’s are released into the air when leaks occur, which are characterized as fugitive.
Moreover, during the manufacturing process, spills can occur which can emit VOC’s. Solvents, resins or other product can spill on the ground, thus spreading over an area, vaporize and become a fugitive emission (Emission Inventory Prevention Program, 2005).
Since latex paint contains acrylics, vinyls and epoxies, it can harm the environment if it is poured down the drain, into the storm of the drain or if the liquid is disposed of in our household trash. In doing so, there is a certain process that must be done in order to dispose of the waste.
Paint is a major source of indoor air pollution when drying (Aerias). It is one of the top five environmental hazards; the largest emissions of VOCs come from solvents (Aerias). VOCs and the connection to human health are weak although it has been linked to asthma. Since the paint consists of other chemicals such as aldehyde, formaldehyde, acetaldehyde and benzaldahyde (Pourreau, 2008), some of these chemicals are shown to cause cancer or nervous system problems (Aerias). If paint has been made before 1978, it can contain lead, which can cause health problems; paint made before the 1950’s contained at least 50% lead. According to Environmental Protection Agency (EPA), when the paint is drying, the indoor VOC levels can be 1,000 times the outdoor levels of VOC (Aerias). VOC’s cause so many vapors, which are then evaporated into the air easily because of the large surface areas that are painted (Aerias).
Of course with the leftover paint, there are numerous ways to get rid of it. You can use it up, give it away, swap it, recycle it or dry it up (NH Department of Environmental Services, 2008). By using up your paint, it is the easiest and safest way to get rid of your extra paint; you can store small amounts for touch-ups or small projects. Paint can be given away if there is some leftover. If one is unable to use it up or store for later use, you can give it away to schools, religious and community groups for example, but the can must be unopened, in good quality and with the label on it (Montgomery County, 2013). Another way to get rid of your leftover paint is to swap it. Communities have “paint swaps” in conjunction with their household hazardous waste collection days or on a regular basis at their facility. The can must have never been opened with the label still intact and the paint must be useable to be put in the reuse area. Recycling your leftover paint is another option. There may be recycling centers in some communities where they accept leftover paint. Also, some hazardous waste collection programs may accept the paint.
The last option with your leftover latex paint is to dry it up since liquid latex paint cannot be placed in your regular household trash. The paint in the cans can be up to ¼ full and then hardened by using an absorbent such as kitty litter, newspaper or sawdust (NH Department of Environmental Services, 2008). Once the paint is hardened, it can be disposed of in a sanitary landfill without causing harm to the environment. Furthermore, because latex paint is water-based, leaving the lid off and air-drying can dry it up (NH Department of Environmental Services, 2005). Once the paint in the can is dry, leave the lid off so the garbage collector can see that the paint is hardened; they are not allowed to get paint cans unless the paint is dried up. Liquid paints can spill while waiting to be picked up causing it to leak into the trucks and onto roads, which can cause a huge cleanup challenge (Montgomery County, 2013). If you have a large amount of paint left, pour thin layers of paint about one inch into a cardboard box lined with plastic containing shredded newspaper. Each layer of paint must dry before pouring another on top of it. It is important to put the paint in an area where it is safe from the reach of children and pets. Once the paint is dried, it can then be placed in your trash, which will then be recycled and processed in the county’s resource facility (Montgomery County, 2013). When the paint is dried up in the can, it is incinerated at the facility and the dried paint burns off of the metal can. The steel paint cans and other metals are recovered from the remaining ash and are sent to metal processors for recycling (Montgomery County, 2013).
When using white latex paint to paint a room, we never think about the chemicals that can harm the environment. There are so many chemicals just in the raw materials that have emissions. During the manufacturing process, there are numerous ways in which emissions can be released even if the factory is well monitored. Using the final product on your walls also releases emissions when drying. Although white paint is the most commonly used color to paint with, the overall product releases many emissions and wastes that have effects on our atmosphere.
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