Hot Melt Adhesives and Available Types Used in Industrial Manufacturing
Industrial hot melt adhesives are polymer-based thermoplastic resins that, when melted, are used to bond materials together. Hot melt adhesives are comprised of one or more base polymers combined with tackifiers (which provide stickiness to the adhesive), plasticizers (to provide greater flexibility), and antioxidants (for protection against degradation) to allow for stability, adhesion, and flexibility.
Industrial hot melt is available in a variety of forms, including granular or powder hot melt blocks, pellets, bags, cakes, drums, and pillows. These materials are solid at room temperature, and then heated, melted, and dispensed for a variety of industrial applications.  As the adhesive returns to room temperature, a strong bond is created, adhering the manufacturing components together.
Hot melt can be dispensed as a liquid or, by introducing an inert gas (such as nitrogen) to the hot melt, as a foam.
Industrial Hot Melt Applications
In either liquid or foam form, hot melt adhesive is used across a wide variety of industries including  aerospace; automotive; product assembly; furniture making, cabinetry, and upholstery; product packaging; book binding; and non-woven sanitary hygiene products.
Aerospace and automobile manufacturers utilize hot melt adhesives for potting electronics (a process used to protect sensitive components from impact or vibration), as well as sealing rivets, seams, and joints. Additionally, hot melt foam is used in airplanes and cars as insulation around doors and windows to reduce vibrations and noise, as well as in seat assembly.
The pages in books and magazines are kept securely bound together using HMAs. The packaging industry depends on a strong adhesive bond to keep the flaps of corrugated boxes and cartons securely closed.
Non-woven personal hygiene products are manufactured by utilizing hot melt adhesives throughout the manufacturing process, including adhering the elastic strands in the leg openings and waistbands, bonding the fabric layers together to secure and stabilize the wetness core, and affixing the fastening tapes to the waistband.
Charring
Charring is a key concern when working with hot melt adhesives, as char (degraded adhesives that have oxidized, hardened into a gel, and been blackened and burned) can negatively affect the adhesives, cause equipment failure, and lead to a shut-down in production.
Key causes of charring include overheating (typically as a result of either using a temperature that is too high for a particular hotmelt, excessive heating times, or incorrect melt tank size); oxidation (exposing the adhesives to too much oxygen), and contamination (from dirt, dust and other materials that fall into the hot melt and burn).
Once formed, the char can break off into pieces that may clog filters and stop up spray and bead nozzles. The pieces of char can work their way onto the materials to be bonded, leaving marks, streaks, and uneven surfaces. Eventually, bits of char may get into hoses and pumps, breaking seals and scoring and damaging hoses and pump walls.
Why Nitrogen is Used for Hot Melt Adhesive
To reduce potential damage from charring, hot melt operators may elect to blanket the adhesives with nitrogen (N2) in a process by which nitrogen, an oxygen depleting gas, is piped into the space between the hot melt adhesive and the top of the hopper or melt tank. The nitrogen blanket protects the adhesive by creating a barrier against falling debris, and it also removes oxygen and moisture which may cause the hotmelt to oxidize and form char .
Oxygen Monitors Improves Quality Control and Helps Protect Employees
To preserve the integrity of the hot melt while blanketing with nitrogen, employees must maintain proper oxygen levels within hoppers or melt tanks, as too much oxygen can cause oxidation. Proper oxygen monitoring equipment should be placed inside melt tanks to measure and control oxygen levels.  A nitrogen leak could lead to failure of the nitrogen blanket, which could compromise the integrity of the adhesives.
Moreover, wherever nitrogen is used, the possibility of nitrogen leaks poses potential risks to humans. Since nitrogen displaces oxygen, a leak could deprive the air of oxygen, thereby creating a possible health hazard for personnel. When there is not enough oxygen in the air, persons working in the area can become disoriented, lose consciousness, or even suffocate due to the lack of oxygen. Since nitrogen lacks color and odor, there is no way, absent appropriate monitoring, for employees to detect a leak.
Best practice calls for oxygen deficiency monitors to be installed anywhere there is a risk of gas leaks. As such, oxygen monitors should be placed wherever nitrogen is stored, and in all areas where nitrogen is used.
PureAire O2 Deficiency Monitors
PureAire Monitoring Systems’ line of Oxygen Deficiency Monitors and Water Resistant Sample Draw Oxygen Monitors continuously track levels of oxygen and will alert hotmelt personnel to nitrogen leaks before employees’ health is put at risk.  In the event of a nitrogen gas leak, and a decrease in oxygen to an unsafe level, the monitor will set off an alarm, complete with horns and flashing lights, alerting employees to evacuate the area.
PureAire’s Water Resistant Sample Draw Oxygen Monitor is a self-contained oxygen deficiency system that is suitable for remote sampling of oxygen levels in confined spaces, hot melt tanks, and other locations where remote oxygen monitoring is required. The built-in pump samples oxygen levels from up to 100 feet away.
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PureAire oxygen monitors measure oxygen 24/7, with no time-consuming maintenance or calibration required. Built with zirconium oxide sensor cells to ensure longevity, PureAire’s O2 monitors can last, trouble-free, for over 10 years under normal operating conditions.Each PureAire O2 monitor has an easy to read screen, which displays current oxygen levels, for at-a-glance readings by hot melt manufacturers, who derive peace of mind from the monitor’s presence and reliability.

Pharmaceutical firms research, develop, and manufacture over-the-counter and prescription drugs and medicines. Usage of these drugs includes, but is not limited to, vaccinations, treatment for chronic conditions, and pain management.
To protect the health and well-being of the public, the pharmaceutical industry is one of the most highly regulated industries. For instance, in the United States, the Food and Drug Administration (FDA) carefully monitors pharmaceutical companies to ensure they are complying with the FDA’s Current Good Manufacturing Practice regulations. These regulations contain requirements for the methods, facilities, and controls used in the manufacturing, processing, and packaging of a drug product.  The regulations are intended to ensure that a product is safe for use, and that it contains the ingredients and strengths it claims to have.
Pharmaceutical Manufacturers Rely on Nitrogen
Pharmaceutical manufacturers rely on nitrogen(N2) (an abundant, inert gas which makes up 78% of the air we breathe) for a wide range of uses, including everything from mixing raw materials, to cryogenic grinding (a process using liquid nitrogen to create ultra-fine, uniform particles), to purging oxygen from packaging.
A sterile environment is critical throughout the drug manufacturing and packaging processes. Nitrogen is used to remove oxygen (O2), moisture, and other possible contaminants, in order to create and maintain a sterile environment for production and packaging.
Nitrogen blanketing is the process by which pharmaceutical manufacturers create an inert, non-reactive, environment for safely mixing chemical compounds. Blanketing with nitrogen safeguards against corrosion and oxidation, and prevents possible volatile reactions that might occur if O2 were present, as some medicinal compounds can be highly combustible when exposed to oxygen.
Oxygen and moisture are purged from packaging not only to maintain sterility but also to protect products during transport, and prolong the stability and shelf life of the packaged drugs.
Oxygen Monitors Can Reduce Risk in Pharmaceutical Manufacturing Facilities Utilizing Nitrogen
Nitrogen is an oxygen-depleting gas that is both odorless and colorless. As such, absent appropriate monitoring, workers would be unable to detect a nitrogen leak if one were to occur in a gas cylinder or line. When there is not enough oxygen in the air, persons working in the area can become disoriented, lose consciousness, or even suffocate due to the lack of oxygen.
Fortunately, by utilizing a top-quality oxygen monitor, also known as an oxygen deficiency monitor, pharmaceutical personnel can track oxygen levels and detect nitrogen leaks before an employee’s health is jeopardized.
PureAire Monitors
PureAire Monitoring Systems’ oxygen deficiency monitors continuously track levels of oxygen and will detect nitrogen leaks before the health of pharmaceutical personnel is put at risk. Built with zirconium oxide sensor cells to ensure longevity, PureAire’s O2 monitors can last, trouble-free, for over 10 years under normal operating conditions.  In the event of a nitrogen gas leak, and a decrease in oxygen to an unsafe level, the monitor will set off an alarm, complete with horns and flashing lights, alerting employees to evacuate the area.
Best practice calls for oxygen deficiency monitors to be installed anywhere there is a risk of gas leaks. The oxygen monitors should be placed wherever nitrogen is stored, and in all rooms and areas where nitrogen is used.
PureAire oxygen monitors measure oxygen 24/7, with no time-consuming maintenance or calibration required.
Each PureAire O2 monitor has an easy to read screen, which displays current oxygen levels, for at-a-glance readings by pharmaceutical manufacturing personnel, who derive peace of mind from the monitor’s presence and reliability.

​What is Nitrogen Blanketing?
Nitrogen (N2) blanketing is a process by which nitrogen is added to fill the headspace (the area between the fill line of a tank’s contents and the top of the storage vessel) to eliminate oxygen and moisture from storage tanks. Nitrogen is commonly used to blanket due to its extremely low reactivity with other substances, as well as its availability and relatively low cost. Other gases can also be used; however, some may be more reactive, and the costs higher, than nitrogen.
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Why Blanket with Nitrogen?
Many industries, including oil, gas, and ethanol refineries, as well as chemical, pharmaceutical, and food processors use nitrogen blanketing to prevent fires and explosions, and to preserve product quality.
Nitrogen blanketing can protect facilities from potentially catastrophic accidents when manufacturing combustible and explosive chemicals, such as ethanol and other volatile materials, since removing oxygen eliminates the possibility of a fire and/or an explosion. Moreover, tank blanketing with nitrogen prevents oxygen, water, and other unwanted substances from coming into contact with the contents of the storage tanks, and/or causing undue wear of the tanks themselves, as oxygen and moisture inside storage tanks can cause evaporation and corrosion that may result in structural damage to the tanks.
Cooking oil processors typically blanket with N2 to remove oxygen, which could otherwise oxidize the contents and negatively affect the taste and, might decrease the shelf life of the oils.
Monitoring Mitigates Risks in Nitrogen Blanketing
Depending upon the needs of the facility and the type of tank, nitrogen is commonly supplied by one of the following methods: continuous purge (a constant flow of nitrogen), pressure control (N2 is added to maintain a set pressure within the tank), and concentration control.
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The concentration control method works by using an oxygen detection monitor, in conjunction with a nitrogen generator, to continuously measure the level of oxygen inside the storage tank, and, if necessary, owing to elevated oxygen levels, add nitrogen to eliminate excess oxygen in the tank.

To ensure facility safety, protect personnel, and preserve the integrity of the tanks’ contents while blanketing with nitrogen, employees in facilities utilizing concentration control must maintain proper oxygen levels within storage tanks, as too much oxygen can cause an explosion.

Proper oxygen monitoring equipment should be placed inside storage tanks to measure and control oxygen levels.  Oxygen monitors should also be placed in any area where nitrogen is stored or used. Further, the O2 detection equipment should be capable of activating visual and audible alarms and, in the event of a nitrogen leak, stop the flow of nitrogen.

The same property–oxygen displacement –that makes nitrogen blanketing such a valuable process, can be deadly if nitrogen leaks from the supply lines or storage containers. Employees could suffocate from breathing oxygen-deficient air and, since N2 lacks color, and odor, there is no way, absent appropriate monitoring, to determine if there has been a leak.
PureAire Monitors
PureAire Monitoring Systems’ Explosion-Proof Oxygen Deficiency Monitor is perfect for facilities that use inert gases including, but not limited to, nitrogen, helium, and argon. The enclosure is specifically designed to prevent ignition of an explosion. The monitor is well suited for environments such as ethanol refineries, chemical manufactures, corn and grain processing facilities, powder coating plants, and the oil and gas industry, where combustible materials, dust, and ignitable fibers are present.

The Explosion-Proof Oxygen Monitor’s built-in pump continuously samples oxygen levels from up to 100 feet away, making it ideal for use with storage tanks, confined spaces, and other hard to reach areas where oxygen monitoring is essential.

The monitor constantly measures changes in oxygen levels and can be programmed to control the flow of nitrogen as needed to ensure safe blanketing.  Additionally, should oxygen levels outside the storage tank drop to an OSHA action level, PureAire’s monitor will set off alarms, complete with horns and flashing lights, alerting personnel to evacuate the area.
The monitor will remain accurate at temperatures as low as -40C. PureAire’s durable, non-depleting, zirconium oxide sensor will last up to 10+ years in a normal environment without needing to be replaced.PureAire oxygen monitors measure oxygen 24/7, with no time-consuming maintenance or calibration required.

In short, PureAire’s Explosion-Proof Oxygen Monitor enables oil, gas, and ethanol refineries, food processors, and other industries blanketing with nitrogen, to preserve, in a cost-effective manner, the well-being of their employees, the integrity of their products and safety of their facilities.