A 55 gallon plastic drum is a storage or shipping container made of a high density industrial strength polymer with thick walls that provide endurance, strength, and longevity for the containment of a wide variety of substances and materials. Their seamless construction makes them ideal for the safe and secure storage and containment of harmful and hazardous solids and fluids.
The rigidity, durability, and toughness of 55 gallon plastic drums has made them a major asset to distributors, shippers, warehousing operations, and other forms of shipping and storing facilities. This singular attribute has enhanced and broadened their use in the chemical, food, and manufacturing industries.
Chapter 2 – How 55 Gallon Plastic Drums are Made
The process for the manufacturing of 55 gallon drums begins with the selection of the correct high density polymer, which may be low density for certain types of drums. Regardless of the type of drum, the polymers for drums start as a resin or pellets that can come from recycled plastic material or newly formed resin from the resin manufacturing process.
Though the appearance of resins is the same for every type, the strength and density varies between the different types. Resins are a viscous material that changes into a rigid polymer when put through the curing process. Though they are naturally occurring, modern production methods produce synthetic versions that have the same properties as the natural versions.
The three processes used to produce 55 gallon plastic drums are rotational, injection, and injection blow molding with injection blow molding being the most common and efficient. In the blow molding and injection molding processes, resin pellets are melted before being inserted into the mold cavity. Rotational molding uses a resin powder that is melted in the heated mold.
Though resin pellets are clear or white, they can have colorant added to give 55 gallon plastic drums an assortment of colors. In most cases, the drums are white, yellow, or blue with other colors being available from producers upon request. In every one of the different manufacturing processes, the resin pellets are melted before being processed. The melted resin is formed into a parison, a hollow tube.
A key to the longevity of 55 gallon plastic drums is the addition of a UV inhibitor to the resin pellets since outdoor exposure to sunlight can degrade plastics in a short time. The best color used to fight UV damage is black with white being the least effective.
Blow Molding Drums
The most common process for the manufacturing of 55 gallon plastic drums is blow molding. The name of the process is a description of it since it involves injecting the parison into a mold, which is blown and forced by pressure to the sides of the mold. There are three forms of blow molding, which are extrusion, injection, and injection straight. The difference between the three types is based on how they form the parison, its size, and how it moves between the halves of the mold.
Feeding Plastic Pellets
The resin pellets are fed into the hopper manually or automatically where the pellets enter an extruder through the feed barrel. In the extruder, the pellets are heated and moved along to the blow molding die. Heating elements, attached to the outside of the screw drive, heat and melt the pellets so that they can form into the parison for formation in the mold.
The plastic extruder is an essential aspect of the heating process since it evenly heats the pellets such that the pellets in the barrel are heating to the exact same temperature. This is critical for avoiding errors and deformations in the final 55 gallon plastic drum.
Inserted into the Mold
The parison created by the extruder is fed into the open mold that is in the shape of the 55 gallon plastic barrel. As can be seen in the diagram below, the parison is a long tube in the shape of a drape or curtain that hangs between the two sections of the die.
Closing the Die
Pneumatically or hydraulically, the sections of the die are pushed together. The bottom and top of the parison is sealed between the die halves with an opening on the top to allow the pressurized air to force the parison to the walls of the die.
Air Being Forced into Parison
As can be seen in the diagram below, air under great pressure is blown into the parison forcing it to the sides of the mold. The pressure of the air ensures that the parison is evenly distributed to the surface of the mold. The power behind the air eliminates any concern for bubbles, imperfections, or flaws in the final product.
Removal of Solidified Drum
The die remains closed until the parison or newly formed drum has cooled. The process of cooling varies depending on the type of polymer being used. To remove the completed drum, the pneumatic or hydraulic motor pulls the die halves apart such that the drum can be easily removed, as can be seen in the diagram.
Rotational Molding Drums
Unlike injection and blow molding, rotational molding begins with resin powder, which is not heated or melted before being inserted into the mold. The powdered material is heated in the mold during processing.
The design of rotational molding is to produce hollowed products using steel or aluminum molds that have rigid configurations. To begin the rotational process, the interior of the mold is conditioned with a release agent for easy removal of the drum at the end of the process. Other varieties of the process include draft angles, which are tapers on the drum, that allow for ease of removal without the need for a release agent. As can be seen in the diagram below, the resin powder is loaded into the mold.
The mold is sealed and rotated on two planes to evenly spread the heated resin powder over the walls of the mold. In the diagram below, the heated mold is revolving as the blue frame turns on the axis of the frame. The particulate plastic matter is evenly spread over the interior surface of the heated mold and fuses in layers until it is completely fused, and the desired shape and wall thickness is achieved. The thickness, endurance, strength, and walls are determined by the amount of powder risen placed in the mold.
This method of rotational molding is one of the many varieties used to produce 55 gallon plastic drums.
Chapter Three - Types of Plastics Used to Produce 55 Gallon Plastic Drums
Of the many materials available for product production, plastics are the most used and adaptable for the manufacturing of industrial products as well as products for home use. The durability, strength, and flexibility of plastic has made it an essential part of a wide variety of products including plastic drums for storage, transport, and shipping use.
Unlike the plastics available for conventional products, the types of plastics for the manufacturer of drums must be of high endurance and have the ability to withstand stressful use. These conditions require polymers with specific mechanical properties and characteristics.
Types of Plastics Used to Produce 55 Gallon Plastic Drums
To most of us, all plastics are the same from ones used to make cups and plates to others that produce barrels and storage containers. In reality, there are many thousands of types of plastics that are produced using different base chemistries, derivations, and additives that provide a wide range of products that are both functional and aesthetic.
For the manufacturing of 55 gallon plastic drums, the types of plastics must be exceptionally resilient and strong. The ones that are commonly used include polyvinyl chloride (PVC), high-density polyethylene (HDPE), nylon, and polystyrene. These types of plastics have been used since the 1960s as an alternative to making drums from steel.
Polyvinyl Chloride Drums (PVC)
Polyvinyl chloride is a synthetic resin that is produced from the polymerization of vinyl chloride. It is the second most produced plastic in use by plastic product manufacturers. When vinyl chloride is treated with monomers, it undergoes the polymerization process that turns it into polyvinyl chloride. The popularity of PVC is based on its rigidity, strength, and flame resistance, which makes it ideal for storing flammable and toxic substances.
High-Density Polyethylene Drums (HDPE)
High-Density Polyethylene is a thermoplastic polymer that is strong, durable, lightweight, and chemically resistant. HDPE is made from petroleum using a process that is known as cracking where petroleum is exposed to intense heat to create ethylene gas. During the process, the ethylene gas molecules attach to polymers to form polyethylene. The sludgy polyethylene is further processed to form granules to produce the polymer material.
Nylon Drums (PA)
Nylon plastic is used to produce 55 gallon plastic drums due to its nonreactivity, low moisture absorption, and resistance to chemicals. Plastics made from nylon are known as polyamides, which is a thermoplastic. It is made by reacting together two molecules through the use of heat and pressure to form sheets that are shredded into chips of raw nylon plastic.
Polystyrene Drums (PS)
Polystyrene is made through the polymerization of styrene. When it is copolymerized with other forms of polymers, it becomes harder and more rigid, which broadens its usefulness in the manufacturing of plastic drums. The styrene in polystyrene is produced by a reaction between ethylene and benzene in the presence of aluminum chloride, which makes ethylbenzene from which styrene is made. At one time, polystyrene was made from chlorofluorocarbon, a process that has been banned for environmental reasons.
Polystyrene cups, containers, and trays are some of the ways that most people see polystyrene. When it is blended with other polymers, it hardens and becomes more rigid for the production of 55 gallon plastic drums.
Chapter Four - Uses for 55 Gallon Plastic Drums
The discussion of the use of 55 gallon plastic drums goes in a wide variety of directions considering the many uses people have found for these adaptable and sturdy containers. What tends to be ignored in the discussion of the use is the main reason for their existence, which is as a storage, shipping, and transport means for liquids, powders, granular materials, chemicals, and food products. These primary functions are the reason they have become so popular in the last sixty years.
The revelation of high density plastic drums has become a major asset for manufacturing and industrial operations. Their durability and strength have made them a practical solution to otherwise dangerous storage conditions.
Uses for 55 Gallon Plastic Drums
Food Grade Drums
For a plastic drum to be used for food storage or transport, it has to meet the standards established by the Food and Drug Administration for cleanliness and sanitary condition. The term food grade refers to plastics that can come in direct contact with food at any stage of its processing, harvesting, production, or packaging. In the case of 55 gallon plastic drums, they have been determined to be safe for long term storage and shipping of foodstuffs.
To receive the designation as food grade, 55 gallon plastic drums are tested, examined, and analyzed to ensure that any form of dyes or chemicals that may be harmful to humans are not present. Once it is determined that a drum is food grade, it can be used to store bulk foods, grains, liquids, and cooking oils.
The pharmaceutical industry relies on 55 gallon plastic drums due to their durability and resistance to the effects of corrosive substances. Drums selected for use in the pharmaceutical industry are made of high density, FDA compliant polyethylene and can withstand the effects of chemicals and hazardous materials.
The tight seal of 55 gallon plastic drums protects their contents against environmental effects and pollution, which can seriously contaminate the contents.
Chemical Storage Drums
Of the many options to store chemicals, 55 gallon plastic drums have been found to be the safest and most reliable. The storage and containment of hazardous and volatile chemicals is a very dangerous and challenging undertaking since it involves precision planning and exceptional plastic materials. One of the major concerns for chemical storage is exposure of toxic substances to the environment. Tightly sealed rust and corrosion resistant 55 gallon plastic drums are the perfect solution for protection from external environmental factors as well as extreme heat and close approximation to other chemicals.
Waste Management Drums
The disposal of industrial waste requires special and well planned handling due to its potential for producing harmful effects to the environment. The structure of 55 gallon plastic drums makes them an ideal means for safely, efficiently, and securely storing and disposing of waste materials from industrial processes. Their tight seal and highly resilient material guarantee that any hazardous substances that are collected will be prevented from causing any form of environmental impact.
The flexibility and endurance of 55 gallon plastic drums has made them the first choice as companies plan ecofriendly methods for waste management. The many varieties and plastic materials available for drum manufacturing provides a wide selection of plastic compositions to meet the needs of any form of waste materials.
Plastic 55 gallon drums have found their greatest use in the oil and petroleum industry. Prior to the development of pipelines, crude raw oil was pumped into drums and shipped. In the beginning, the drums were not durable enough and fell apart or leaked during transport. This led to the development of the steel drum, which was more reliable and resilient.
Though steel drums met the need, when they reached the end of their usefulness, it was difficult to find an appropriate means for storing them, which seemed to be an irresolvable problem until the development of the plastic 55 gallon drum. When the first HDPE 55 gallon drum was produced in the 1960s, it proved to be a leap forward for the oil industry as a means for storing some of the byproducts from oil production.
Traditionally, for many centuries, wine was fermented and stored in wood barrels, which later evolved into stainless steel ones. With the advent of FDA food grade 55 gallon plastic drums, the wine industry has found it to be more economical to use plastic drums for the fermentation and storage of their products. The preference is polyethylene drums that are chemical resistant and highly resilient.
What manufacturers have discovered is that plastic is less expensive to clean, saves space, and is lightweight, which makes handling much easier. The flexibility and high quality of 55 gallon plastic drums has made them an ideal substitution for the traditional wood cask.
Unusual Drum Uses
Aside from the purposeful use for 55 gallon plastic drums as methods for storing and shipping various substances and materials, there has been a rapid rise in their use once they no longer are needed for industrial and manufacturing operations. There is a long list of the unusual, unique, and strange ways that people have made use of 55 gallon plastic drums. Many of the innovative uses have led to manufacturers producing drums specifically to meet a particular need.
Some of the many ways that people have made use of 55 gallon plastic drums include rainwater harvesting, composting, planters, hydroponic system support, aquaponics, root cellars, buoy markers, and wheelbarrows. Though this may seem a bit unusual, it serves the purpose of repurposing the drums for positive and constructive use.
Chapter Five - Types of 55 Gallon Plastic Drums
Plastic 55 gallon drums come in various types depending on the plastic material used to produce them as well as the thickness of their walls. Each of the various kinds of drums are designed to fulfill a particular and discrete function with ones that are manufactured for chemical and hazardous use while others are made to hold powders and food stuffs.
The differentiation between the types of drums is determined by the polymer that is molded to form them with HDPE being the most common. Aside from the different types of plastics, 55 gallon drums are separated by the type of head that they have, which can be an open removable head or closed and sealed one. Much like their chemical composition, the type of head is determined by the function of the drum.
Types of 55 Gallon Drums
Open Head Drums
Open head 55 gallon plastic drums are about 35 inches high and have a 23 inch diameter head or top. The removable cover has a lever or bolt ring locking mechanism that tightly seals the drum when not in use or in storage. The lid can easily be opened to load any form of contents. Open head drums are used in conditions where users require constant, unobstructed access.
Lids for Open Head Drums
The lids for 55 gallon plastic drums come in as many varieties as there are types of drums. The many gauges of steel lids are used for their strength, endurance, and resilience. Most metal lids have an EPDM rubber gasket to seal the lid to the drum.
Low-density polyethylene (LDPE) is used for lids due to its flexibility and ability to be molded since it is less dense and easier to shape than HDPE. The exceptional heat and moisture resistance of LDPE has made it an ideal choice for open head drum lids. In cases where there is a concern for UV rays, covers are made from vinyl and HDPE.
Closed Head Drums
Unlike open head drums, closed or tight head drums are sealed with access available through an opening in the top of the drum with a second small opening for ventilation. Closed head drums are normally 35 inches high and have a 23 inch diameter on the top. The top and bottom of the drum are flanged and permanently sealed by their single unit construction.
The closed head design is used for the shipping and containing of hazardous substances that may be volatile is exposed to the atmosphere. They provide a safe and secure method for shipping waste materials and unstable substances. The use of closed head drums is limited to the handling of various viscosity liquids.
The top of closed head drums has two bung hole threaded openings with one being for ventilation and the other for accessing the contents. The type of bung hole, whether it is plastic or metal, depends on the contents of the drum.
Chapter Six - Benefits of Using 55 Gallon Plastic Drums
There are an endless number of reasons why 55 gallon drums have replaced aluminum and steel drums as the main method for storing and shipping granular, powder, and liquid substances. Since their introduction in the 1960s, 55 gallon plastic drums have rapidly grown to be the number one method for barrel and drum storage.
Unlike the other materials used to manufacture drums, plastic can easily be repurposed and recycled for other uses. Though this can be said to be true for aluminum and steel, the processes for recycling those materials are highly complex and time consuming. In the case of plastic drums, they can be shredded and transformed into plastic pellets with less effort.
Benefits of Using 55 Gallon Plastic Drums
The plastic materials used to make plastic drums are extremely tough and durable, which increases their life span. Plastic 55 gallon drums are resistant to weathering, temperature fluctuations, and damp, high humidity, or high moisture conditions. Plastic is not susceptible to the influence of ultraviolet rays avoiding any concern for storing drums in the sun. The tight and secure seal of plastic drums ensures that they will not leak or sweat while in storage or during transport.
One of the buzzwords in business is sustainability, the ability to maintain and sustain our way of life for future generations. Plastic drums, once they have ended their usefulness in industry, can be repurposed in hundreds of different ways from being planters for the backyard to being ground up to produce other products. This one characteristic of plastic drums has major benefits across the full spectrum of the environmental cycle.
Reduction of Landfill Use
An added benefit of repurposing 55 gallon plastic drums is that they will not end up in a landfill or waste dump. The multiple uses of 55 gallon plastic drums eliminates the need to find a method for disposing of them, significantly eliminating an aspect of a growing waste management problem.
The various polymers used in the manufacturing of 55 gallon plastic drums are inert and resistant to low or high pH contents. This characteristic is the reason that they are ideal for shipping and storing chemicals and potentially volatile substances.
The major reason that 55 gallon plastic drums have become such a valuable asset is their cost. It is the main reason that they were so rapidly accepted at their introduction. Plastic is easier, less expensive, and more practical to produce than glass, metal, or any other forms of storage container materials. Plastic 55 gallon drums can be used for years and never show use, wear, or damage. The resilience and durability of plastic is what sets it apart from any other types of materials.
The manufacturers of 55 gallon plastic drums are very much aware of the many benefits of their products. The engineers and experts that design and create 55 gallon plastic drums realize that what they produce are a safe, secure, and airtight method for shipping and storing a wide range of materials. They work closely with their customers to ensure that the container the customer receives is the one that exactly fits their shipping needs.
Chapter Seven - United Nations Standards for 55 Gallon Plastic Drums
The United States Department of Transportation has established standards for shipping containers that all manufacturers, producers, and industries are required to follow. In addition to the national standards, the United Nations has developed a rating system regarding shipping containers that companies are advised to follow regarding international shipment of liquids, substances, and other materials. A higher UN rated drum can work with lower rating regulations but cannot work as a container above its rating level.
United Nations Standards for 55 Gallon Plastic Drums
The UN system is a set of numbers and codes that identifies and rates a container. The rating for a 55 gallon plastic drum would follow a particular sequence. The example below is a brief explanation of how a 55 gallon plastic drum would be identified under the UN rating system.
1 – The number one in the first position in the UN system indicates that the container is a drum.
H – H, in the second position is the type of material from which the container is made, which is plastic, in this case.
1 or 2 – The third position is the indicator of whether the drum is open or closed head with 1 being closed head and 2 being open head.
X – The "X" after the backslash indicates what packing group the container is equipment hold. There are three groupings, which can be seen below. The Roman numeral I is for hazardous materials while III is for the least hazardous types with II being for materials that are mildly dangerous.
X packaging covers all three packing groups: I, II, or III
Y packaging covers packing groups II and III only
Z packaging covers packing group III only
420 – The final number after the X is a descriptor for the gross mass that the container has been rated to handle. This is the weight of the container and its contents that has been tested and approved.
L – The final letter after the second backslash indicates whether the container is rated of solids or liquids with S standing for solids and L standings for liquids.
By providing a rating for containers, the UN hopes to ensure the safety of others, preserve the environment, and help companies avoid expensive fines. UN ratings last for five years after which an extension can be requested from the department of transportation (DOT). If no such extension is requested, UN rated drums should be disposed of.
A 55 gallon plastic drum is a storage or shipping container made of a high density industrial strength polymer with thick walls that provide endurance, strength, and longevity for the containment of a wide variety of substances and materials.
The rigidity, durability, and toughness of 55 gallon plastic drums has made them a major asset to distributors, shippers, warehousing operations, and other forms of shipping and storing facilities.
The process for the manufacturing of 55 gallon drums begins with the selection of the correct high density polymer, which may be low density for certain types of drums.
The durability, strength, and flexibility of plastic has made it an essential part of a wide variety of products including plastic drums for storage, transport, and shipping use.
The discussion of the use of 55 gallon plastic drums goes in a wide variety of directions considering the many uses people have found for these adaptable and sturdy containers.
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