When selecting a material for an industrial operation, considering its properties and use cases are of the utmost importance to ensure you make the right choice. Today we explore the key differences between polyester and polyurethane. Both these materials have “poly” in the name, are synthesized from polyols, and can be used in automotive, textiles, coatings and even footwear applications. At a glance you could get them easily confused. Because of the potential confusion we will unpack both materials at depth. This discussion will offer a breakdown of their respective properties and applications. At PSI, we specialize in polyurethane products and understand the nuances between different materials. By highlighting the unique benefits of each, we aim to provide you with a “poly”-technical guide to assist you in selecting the right material for your specific needs.
To get started, let’s look at polyester.
Understanding Polyester Material
Polyester is a polymer, a compound made of repeating units or monomers that primarily consist of polyethylene terephthalate (PET). It is an elastomer, meaning it can stretch and return to its original size. Because of the aforementioned, polyester is well-regarded for its strength and resistance to deformation. These characteristics make polyester the best possible choice for applications requiring a material that can endure stress without significant degradation.
Properties of Polyester
Polyester is a workhorse material, what we mean by this is that it can withstand a variety of environmental conditions while maintaining its structural integrity. It has excellent abrasion resistance and a high surface strength. The most prized properties of polyester include its durability, flexibility and strength.
Durability: Polyester is known for its resistance to wear and tear thanks to its ability to withstand stretching, tearing and abrasion. It is also recognized for being impervious to environmental factors such as sunlight and moisture and does not degrade when exposed to these conditions. Its durability also extends past environmental factors and includes chemical resistance; it can handle acids, oxidizers and most solvents.
Flexibility: Being an elastomer, polyester can retain its structural integrity under strain and thereafter. The material’s flexibility allows it to be shaped into various configurations and forms while maintaining its structural integrity. This allows it to be used in numerous applications like bottles, automotive door panels, as well as thermal and acoustic insulation.
Strength: The high tensile strength of polyester is ascribed to a combination of factors including its crystalline polymer molecular structure and synthetic nature. This high strength makes it a perfect choice for applications like ropes and tire cords.
Polyester Applications
As discussed above, the diverse properties of polyester make it suitable for various industrial and commercial uses. These uses include fabrics, packaging and industrial products like conveyor belts and insulation.
Fabrics: In the textile industry, polyester is the material of choice when it comes to resilience and durability. It is also relatively wrinkle-resistant and has low moisture absorption which makes it ideal for activewear and outdoor clothing. It is used for a range of products which varies from curtains and bed linens to automotive upholstery and protective clothing like reflective vests and overalls.
Packaging: If you have ever seen a bottle that has the letters PET on it, you know it has been made from polyester, specifically polyethylene terephthalate. Its strength, lightweight nature, and ability to provide a barrier against moisture makes it perfectly suited for packaging. Examples where polyester is used for packaging include plastic bottles, food containers and thermoformed trays.
Industrial Products: In more demanding environments, like industrial settings, polyester is used in the manufacturing of conveyor belts, filters and industrial ropes and slings. Its high tensile strength, flexibility and resistance to wear and tear makes polyester a good choice for heavy-duty applications.
Curious as to which material is best for the task? Contact PSI and let our experts help you choose the right material for the right application.
Now that we have a firmer grasp of the properties and applications of polyester, it is time to shift our focus to polyurethane.
Understanding Polyurethane Material
To best understand polyurethane, a basic comprehension of its chemistry is necessary. Polyurethane is an elastomer (like polyester) that is formed through the reaction of isocyanate and a polyol. Now, without getting too technical, a polyol is an organic compound that contains multiple hydroxyl groups.
Two common polyols are polyether and, you guessed it, polyester. The type of polyol used determines the characteristics of the polyurethane. If the polyol in the polyurethane is polyester the polyurethane will often exhibit greater abrasion and chemical resistance; whereas polyethers provide excellent shock absorption and are more UV and wear resistant.
Irrespective of the polyol used, polyurethane material is preferred in various applications over traditional (or should we say old fashioned) materials like plastic, rubber and metal.
Properties of Polyurethane
Polyurethane has various properties that make it a stand-out material in plenty of environments. To see the full list of polyurethane properties, be sure to read our Polyurethane 101 blog.
Strength & Impact Resistance: Polyurethane materials exhibit excellent tensile strength and abrasion resistance, which makes them perfect for applications that require durability. Its ability to absorb shock and return to its original form without cracking or breaking makes polyurethane an excellent replacement for applications traditionally dominated by plastic. Polyurethane is also not brittle, which means that irrespective of the durometer (level of hardness), it will maintain its integrity and strength.
Flexibility: One of the key advantages of polyurethane is its ability to maintain flexibility across a wide range of temperatures and conditions. This flexibility allows it to absorb impact and vibrations, making it suitable for dynamic environments such as heavy machinery and vehicle components.
Abrasion and Chemical Resistance: Polyurethane has great abrasion and chemical resistance. This results in longer life cycles and less downtime in industrial settings. Polyurethane’s resistance to abrasion has been shown to outperform other materials like rubber and plastics by a factor of five-to-one to even ten-to-one. Polyurethane is also resistant to hydrocarbons, petroleum products and mineral-based oils. This makes it ideal to use in environments such as oil and gas drilling operations, chemical plants and heavy manufacturing facilities.
Polyurethane Applications
Polyurethane meets the requirements for numerous applications thanks to its wide range of properties. Industries that rely on polyurethane materials include automotive manufacturing, furniture manufacturers and manufacturing facilities. Below we review a few of the applications that polyurethane can be used for.
Foams: Polyurethane foams are used in a multitude of applications, including furniture, automotive seating, and insulation. The foams provide cushioning, comfort, and thermal insulation, making them indispensable in both consumer and industrial products.
Automotive Components: Polyurethane is used in various products within the automotive sector. The ability to custom-make components and the strength and impact resistance of polyurethane makes it suited for numerous applications. These applications include products like polyurethane sheets, gaskets, washers, engine mounts, bumpers, and bushings.
Manufacturing Facilities: Whether it’s conveyor belts, wheels, rollers or seals, polyurethane materials are a key component of manufacturing facilities. The properties of polyurethane materials like high durability, flexibility and superior resistance to abrasion and impact make them a practical choice for use in manufacturing facilities.
Polyurethane’s unique properties offer significant advantages over traditional materials, providing enhanced durability and cost-effectiveness in demanding applications.
To learn more about the polymorphic nature of polyurethane, contact PSI.
Polyester vs. Polyurethane: Key Differences
Now that we know the properties and common applications of both polyester and polyurethane, it is time to better differentiate the two. When it comes to choosing the right material, it’s essential to consider the specific needs of your application. Below we will look at the key differences and which is best when it comes to durability, flexibility, versatility, cost and availability. By understanding these key differences, one can better decide between the two when it comes to specific applications.
Material Durability
Polyester: Polyester provides resistance to stretching and shrinking and maintains its form even after exposure to factors like UV light. It is, however, not on the same level as polyurethane. Polyester is best suited for applications that do not require a heavy-duty fit for purpose, including lightweight packaging materials, textiles and everyday household items.
Polyurethane: Polyurethane is the best choice when it comes to applications that require high abrasion resistance and impact strength. Its elasticity and toughness allow it to withstand harsh conditions like constant motion or mechanical stress without deteriorating. Heavy-duty applications that are perfect for polyurethane include conveyor belts and automotive components.
Flexibility and Versatility
Polyester: Polyester is a flexible material, but only under select conditions like stable temperatures. It is generally less versatile compared to polyurethane. This is ascribed to polyester’s rigid molecular structure. It, however, performs well in stable environments but not in those that involve fluctuating temperatures or heavy mechanical stress.
Polyurethane: The flexibility of polyurethane materials is unmatched. Its ability to maintain flexibility without cracking or breaking under temperature changes or mechanical stress makes it ideal in a range of applications ranging from dynamic seals in machinery to shock-absorbing pads in athletic equipment.
Cost and Availability
Polyester: Polyester is generally a more cost-effective material than polyurethane and is also more widely available. This is due to its extensive use in various industries, such as textiles and packaging, which benefits from economies of scale in production. Its production costs are also lower, accredited to its widespread adoption and relatively simpler synthesis.
Polyurethane: Polyurethane is more expensive to produce and procure in comparison to polyester. This is ascribed to the fact that polyurethane is produced from polyols and isocyanate. Its higher costs are justified however by its performance benefits. These benefits are very prominent in applications that require high abrasion resistance, flexibility and custom requirements.
Curious about polyurethane and want to learn more? Check out our Polyurethane 101 blog.
We hope this polytechnical guide has provided you with a better understanding of the key differences between polyester and polyurethane.
If you require further information or are curious about how to implement polyurethane in your operations, get in touch with one of the experts at PSI.
