What Is Vinyl Acetate
Vinyl acetate, also known as vinyl acetate monomer or VAM, has a chemical formula of C4H4O2. This chemical is primarily used as a raw material in the production of other industrial chemicals. Some of these derivatives include polyvinyl acetate polymers and ethylene-vinyl acetate copolymers. Vinyl acetate and its derivatives are most widely recognized as components used to produce adhesives, but the applications don't stop there. Coatings, resins,films and other substances made with vinyl acetate are present in a range of industrial applications.
Vinyl acetate appears in its pure form as a clear, colorless liquid. It's often described as having a sweet, fruity smell that can seem sharp to some people. It is slightly soluble in water and evaporates in air, though its vapors are heavier than air. Vinyl acetate is also highly flammable and may ignite in the presence of heat, sparks, or flames in the workplace.
In this article you will learn:
What Is Vinyl Acetate Made Of
Vinyl acetate is not a naturally occurring resource. Monomeric vinyl acetate is derived in a lab from ethylene. The ethylene is reacted with oxygen and acetic acid using a vapor-phase reaction. In this reaction, chemists bubble the ethylene through anhydrous acetic acid, using palladium chloride as a catalyst. The reaction is usually completed in the presence of an inhibitor, which prevents the reaction from spontaneously producing polymers.
Once created and separated, the vinyl acetate can be shipped or further processed into vinyl acetate derivatives. Most often, vinyl acetate is converted into a polymer, which is accomplished under the action of free-radical initiators.
Is Vinyl Acetate Toxic
One of the primary questions regarding vinyl acetate is its safety in the workplace. Vinyl acetate does pose some hazards and is considered slightly toxic, though the risk posed to human health is largely undefined. At present, the risks posed tohuman health are defined as follows:
Short-term exposure to vinyl acetate in the air has been shown to cause irritation of the eyes, nose, and throat. These effects scale in severity with the relative presence of vinyl acetate in the air. Additionally, direct contact of vinyl acetate with the skin or eyes can result in blistering and irritation.
Chronic occupational exposure to vinyl acetate has been shown to increase instances of upper respiratory tract irritation.
Researchers are currently pursuing more information on the potential health hazards posed by vinyl acetate. At present, there is very limited information as to whether exposure to vinyl acetate over time has more severe long-term effects. Some of the areas currently being researched include:
The effect of chronic exposure on the immune system and nervous system of humans is undefined, but observations in animal trials have discovered negative effects in these areas.
There is no information to show that vinyl acetate exposure in humans results in birth defects or low birth weights. However, the risk posed to humans is still undefined, and the area is under research, as animals exposed to vinyl acetate during pregnancy did produce smaller offspring than normal.
Vinyl acetate has not been shown to be carcinogenic to humans. It is, however, listed as a potential carcinogen by the International Agency for Research on Cancer. This classification is due to the fact that animal trials showed an increased rateof nasal cancer with high exposure over the course of two years.
At present, the federal government has imposed standards and guidelines to protect people from the potential negative health effects of vinyl acetate. Spills of over 5,000 pounds of vinyl acetate into the environment are required to be reported to the National Response Center, and OSHA has set a limit of how much vinyl acetate can be present in the air over an eight-hour shift or 40-hour workweek.
Advantages of Vinyl Acetate
Vinyl acetateand its derivatives possess several unique properties that make them advantageous in the production of various coatings and adhesives. These properties vary depending on the specific derivative, though most within this group exhibit one or more of the propertieslisted above. A few of these properties include:
- Oxygen Barrier: Ethylene vinyl alcohol is a popular derivative of vinyl acetate, known
primarily for its ability to provide a flexible oxygen barrier. This makes it an excellent
barrier resin in food packaging, as it protects foods from spoiling without increasing
- Adhesion: Many of vinyl acetate's derivatives possess adhesive andgap-filling
properties, allowing them to stick effectively to a variety of surfaces. This makes these
substances ideal for the production of various types of glues and adhesives in commercial
and industrial applications.
- Toughness: Upon drying or setting,many vinyl acetate derivatives are exceptionally
tough, resisting wear and tear usually by exhibiting some level of elasticity. This property
makes them an ideal ingredient in the production of coatings and films.
- Clarity: Vinyl acetate and its derivatives are clear and colorless, allowing them to be used
in a range of applications without affecting the color and finish of a product. This clarity
makes these substances an excellent choice for clear adhesives as well as coatings and
- Chemical Resistance: Vinyl acetate products generally possess some level of resistance
to oil and gas, making them excellent protective coatings.
Vinyl Acetate Derivatives
Vinyl acetate is a monomer and a key intermediate in the production of several polymers and resins, which are used to produce a range of end-products for industrial applications.
Some of the derivatives of vinylacetate include the following:
Polyvinyl acetate, or PVA, is the most significant derivative of vinyl acetate. This amorphous polymer is a thermoplastic, unique in its ability to resist yellowing under thermal stress. It offers excellent gap-filling capabilities and is the hardest of the polyvinyl esters. Unlike vinyl acetate, polyvinyl acetate is not soluble in water because it does not cross-link. It can, however, dissolve in many solvents other than water, such as ethyl alcohol or acetone. PVA is most recognized for its excellent adhesion to the majority of surfaces, including paper, wood, plastic films and metals. Due to these properties, polyvinyl acetate is most commonly used in the production of industrial adhesives and is one of the most common adhesives used in bookbinding. Polyvinyl acetate is also used in the production of paper coatings, paints, and industrial coatings.
Polyvinyl alcohol, or PVOH, is another common derivative of vinyl acetate. Manufactured by dissolving polyvinyl acetate in alcohol, PVOH is a colorless, water-soluble synthetic resin. Most commonly, PVOH is used in the textile industry as a sizing agent, providing greater strength to textile yarns during the textile production process. PVOH is also used as a paper coating to help the surface become more resistant to oils and greases. Outside of these uses, PVOH is widely used as a component in adhesives, packaging films, coatings, and thickeners.
Polyvinyl alcohol can be used to manufacture polyvinyl butyral or PVB. This resin exhibits excellent adhesion, clarity, and toughness in industrial applications, and is often used for adhesion purposes. PVB is most commonly used in the automobile and commercial building industries in the production of laminated glass —PVB provides the protective, transparent interlayer that bonds two panes of glass. Outside of adhesive applications, polyvinyl butyral can also be usedto produce coatings and inks.
Ethylene vinyl alcohol, or EVOH, is a fast-growing use of vinyl acetate monomer. This copolymer of ethylene and vinyl alcohol provides an excellent oxygen barrier superior to most other vinyl acetate derivatives, though this effect decreases in the presence of water. Due to its effectiveness as a gas barrier and chemically resistant coating, EVOH is commonly used in packaging applications as a flexible barrier. Most commonly, EVOH can be found as a barrier resin in food packaging. It's also used in the production of plastic bottles and gasoline tanks.
Vinyl chloride-vinyl acetate copolymers are another common application of vinyl acetate, serving in a variety of roles. Currently, vinyl chloride-vinyl acetate copolymers are most often used in coatings, paints, and adhesives, though historically they have been used in the production of gramophone records and flooring.
Polyvinyl formal, also known as Formvar or PVF, is produced by the hydrolysis and acetalization of polyvinyl acetate. This resin is highly rigid and tough and is primarily used in the production of wire enamel. PVF is also used in metal priming, injection molding, resin reinforcement, thermal adhesives, and magnetic tape.
In total, producing polyvinyl acetate and polyvinyl alcohol makes up approximately 80% of global vinyl acetate monomer production. The remaining production volume goes to theother polymers and resins listed above.
Uses of Vinyl Acetate
Vinyl acetate is the unsung hero of the adhesive industry and many others. While vinyl acetate is rarely used in its pure form, its derivatives are used throughout various industries. The unique chemical properties of vinyl acetate derivatives make them perfectly equipped to tackle a range of industrial applications.
The widespread usage of vinyl acetate derivatives has made it a strong contender in the market. Sales for vinyl acetate have grown substantially in the last decade and are expected to continue growing 4% per year. From glues and resins to paints and textiles, vinyl acetate serves as the essential intermediate for compounds that are integral in the production of many products used in modern daily living.
Vinyl acetate and its derivatives are used in a huge range of industrial applications. Some of them are described in detail below:
Vinyl acetate and its derivatives are most commonly used to produce adhesives. Polyvinyl acetate, polyvinyl alcohol, ethylene-vinyl acetate, and various copolymer derivatives are popularly used as adhesives in various applications. Polyvinyl acetate is by far the most popular. PVA is used in a variety of adhesives —in its emulsified form, it is often included in pastes and glues, but it can also be used as a waterless thermosetting adhesive. Some examples of polyvinyl acetate-based glues include wood glue, carpenter's glue and Elmer's glue.
Due to its excellent chemical resistance, vinyl acetate and its derivates are often used as coatings for a variety of substrates. For example, polyvinyl acetate can be used in the lamination of metal foils, while polyvinyl alcohol is often used as an oil-resistant coating for paper.
The Food and Drug Administration has determined that vinyl acetate may be safely used in food production and packaging. This has allowed vinyl acetate and its derivatives to be used in several areas of the food industry —for example, ethylene vinyl alcohol is often used as a barrier resin for food packaging. Vinyl acetate and derivatives have also been used in the production of food starches as a modifier.
Another common use of vinyl acetate and its derivatives is in the production of resins. Resins are solid or highly viscous substances that are used in every corner of industry as stabilizers, pigments or additive components for plastics and cements. For example, vinyl acetate is commonly used to make barrier resins for plastic bottles, while polyvinyl acetate is often used to produce the resinous components of latex paints. On top of this versatility, polyvinyl acetate-based resins are significantly cheaper than acrylic resins, making them more cost-effective in many applications.
The textile industry uses a range of resins and adhesives in the textile production process. Most notably, Polyvinyl alcohol is used as a sizing agent, improving the strength of textile yarns to reduce the possibility of breakage during the weaving process. Polyvinyl acetate derivatives are also commonly used for textile finishes, providing flexible yet effective protective coatings.
VAM and its derivatives aren't just limited to the above applications. These chemicals are also commonly used as plasticizers, thickeners, and even chewing gum.
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