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Written by admin on August 3, 2023 in UHMW-HDPE and Polyurethane

“What is polyurethane?” – This simple question opens the door to a world of innovation, versatility, and limitless possibilities. Polyurethane, often referred to as ‘PU,’ is a synthetic material that has become an indispensable part of our modern lives. Its unique properties have captivated engineers, designers, and manufacturers globally, leading to its widespread use in everyday products and critical applications across various industries.

In this article, we will explore the fascinating world of polyurethane, gaining insight into what it is, its diverse uses, and why it has become an essential component in the mining industry. From its inception to its current applications, polyurethane’s impact on our lives is truly remarkable. Let’s delve into this versatile material and discover how it continues to shape our world.

Both polyethylene and polypropylene are types of plastics, and they are polymers. The word ‘poly’ means ‘many’ and, therefore, polymers are materials made up of lots of smaller units put together. Most of the polymers can be broken down into distinct parts that act as the building blocks of the polymer, and these single units are called ‘monomers.’ The monomer unit of polyethylene is ethylene whereas the monomer unit of polypropylene is propylene. The main difference between polyethylene and polypropylene is that polyethylene is formed through the polymerisation of ethylene monomer units whereas polypropylene is formed through the polymerisation of propylene monomer units.

What is Polyurethane?

As mentioned above, polyethylene is a polymer made up of the polymerisation of ethylene molecules which are two Carbon alkane units [-CH2CH2-]. It is categorised as a thermoplastic polymer. Most of its physical properties depend on its molecular weight. High-Density Polyethylene (HDPE), Medium-Density Polyethylene (MDPE), and Low-Density Polyethylene (LDPE) are the most common types found. And they are known for their chemical resistivity. That is, they do not react and degrade in the presence of strong acids and strong bases. Polyethylene is inert and translucent. This means that it allows light to pass through, but does not facilitate image formation, unlike in the case of transparent material.

Ethylene can undergo co-polymerisation. In this case, its purity is lost. However, polyethylene undergoes co-polymerisation to a lesser extent when compared to other plastics. Therefore, due to its purity, it is often costlier. There have been serious environmental concerns regarding polyethylene as it doesn’t degrade naturally unless it has been treated. However, many methods have been developed and are been used to solve this issue. Polyethylene is now made from feedstock such as sugar cane, wheat grain, and sugar beet.

Basics of Polyurethane

Polypropylene is also a thermoplastic polymer which is more rigid when compared to polyethylene. As mentioned above, polypropylene is made up of propylene monomer units, which are three Carbon alkane units [–CH2(CH3)CH2-]. Due to its rigid nature, it is often used for making molded material. Propylene is often co-polymerised with ethylene molecules to improve its flexibility. i.e. ethylene propylene rubber. Polypropylene is not as translucent as polyethylene but can be made translucent by un-colouring.

Polypropylene also comes in certain grades depending on its molecular weight. However, most of the polypropylenes come in between the weights of High-Density Polyethylene and Low-Density Polyethylene. It undergoes a chain degradation when exposed to light and gives rise to oxidation reactions forming free radicals which raise further concerns regarding health and safety.

Polyurethane is a synthetic polymer composed of organic units linked by urethane (carbamate) links. The material is known for its properties, which include durability, flexibility, and resilience. All these properties make the material a preferred choice for numerous applications. Polyurethane is also versatile as it exists in various forms, such as foams, elastomers, and thermoplastic polyurethane (TPU). So, let’s dive in and discover the versatility of this material.

Polyurethane Uses: Versatility at Its Finest

People often ask, ‘What is polyurethane used for?’ Polyurethane is considered versatile due to its remarkable ability to adapt and excel in a wide range of applications. This adaptability is a result of its unique chemical structure and properties. Here are some key reasons and uses that will help you know why polyurethane material is hailed as a versatile material:

https://www.sciencedirect.com/topics/chemical-engineering/polyurethane

  • Furniture and Mattresses:

Polyurethane is widely used in furniture and mattresses, and the reason behind this is its cushioning properties. In addition, it also can be molded into various shapes and is known for several polyurethane uses, which is why it becomes an ideal choice for comfortable and supportive seating and sleeping surfaces.

  • Automotive industry:

Polyurethane is also a popular choice in the automotive industry, where it is used to manufacture parts such as car seats, interior panels, steering wheels, and suspension components. The reason that makes it a popular choice is its durability and lightweight. These features also enable them to improve fuel efficiency and overall performance.

  • Construction materials:

In the construction industry, polyurethane is a critical insulation material. Polyurethane is used in the form of rigid foam insulation, which helps it to provide excellent thermal resistance, which also helps to increase energy efficiency in buildings.

Polyurethane in Australian Mining Equipment

Polyurethane is also widely used in Australian Mining Equipment due to its exceptional features and characteristics. Let’s take a look at these characteristics that make the material a popular choice:

  • Wear-resistant Linings:

As mentioned earlier, polyurethane is widely used in the mining industry. Its properties of exceptional abrasion and impact resistance make it suitable for this industry. In addition, it is also employed to create wear-resistant linings for chutes, pipes, and other equipment that come into contact with abrasive materials during mining operations. Along with these characteristics, these linings protect the equipment from premature wear and extend its lifespan.

  • Conveyor belt scrapers:

Conveyor belts are vital for transporting mined materials, and their efficiency can significantly impact mining operations. Here, polyurethane is used to manufacture conveyor belt scapers which help clean and maintain the belts. Thus, it helps ensure the material flow is smooth and uninterrupted.

  • Screen panels:

In mining operations, screening is an essential process that is used to separate valuable minerals from waste materials. Polyurethane screen panels are also used here due to their high durability characteristics and efficient separation capabilities. These panels also can withstand harsh conditions and are resistant to wear. Thus, this results in longer-lasting and more reliable screening processes.

Is Polyurethane Toxic?

Polyurethane is generally considered safe when used as intended and should also be used in compliance with safety regulations. However, it is important to note that different types of polyurethane may have different characteristics, which is why some may contain additives or chemicals that may raise concerns and can be dangerous.

However, stringent quality control measures are in place to ensure that polyurethane products meet safety standards. If you are still unsure about the safety of polyurethane and its products, it is important to consult the manufacturers or relevant authorities for reassurance.

What is Polyurea?

Polyurea is an elastomer substance derived from step-growth polymerisation, which involves combining synthetic resin and isocyanate-reactive materials. Thus, the reaction of an isocyanate part with a resin blend part through the step growth process of polymerisation produces polyurea.

Various formulations of resins and isocyanates can provide the desired setting time, moisture resistance, pigmentation, flame retarding properties, and other unique features.

What are the Unique Features of Polyurea?

No coating system can successfully replace polyurea in all respects, due to its unique physical properties and durability. However, its surface preparation requirements are very stringent.

Polyurea protects wooden, concrete, and steel surfaces and structures from abrasion and corrosion damage. It can help preserve a deteriorating concrete structure and help repair and keep canals intact. It resists scratches, chemicals, oils, and salts in commercial and industrial floor applications. It can also preserve boats and other vessels by protecting from cracking and deterioration. Advantages of polyurea coatings include:

  • Very fast setting (curing time typically 2 to 5 minutes) depending upon the formulation
  • Excellent abrasion and scratch resistance
  • Very stable resistance to weather and environmental conditions
  • Very beneficial elongation characteristics
  • Can be applied in variable temperature conditions, even in high humidity
  • Stable heat resistance up to 130°C (266°F) and short-term rating of 220°C (430°F)
  • Coating thickness can be finely controlled
  • Very effective bonding on correctly prepared surfaces of wood, cement, concrete, and metals
  • Excellent chemical resistance
  • Feasibility of low viscosity, thus enabling mixing and spraying at desired temperatures
  • Can be formulated for a very high tensile strength of up to 4350 ps

How does Polyurea Compare to Epoxy and Polyurethane?

Compared to epoxy coatings, polyurea is greatly superior in moisture resistance, UV resistance (for aliphatic coatings), abrasion resistance, chemical resistance, temperature resistance and durability. It also has a quicker cure time.

Compared to polyurethane, polyurea has superior durability, chemical resistance, and moisture resistance.

What are the Significant Applications for Polyurea Coatings?

Numerous applications benefit from polyurea coatings, including the following:

Pipelines, pumps, and irrigation systems

Polyurea provides corrosion and abrasion protection for pipelines that carry abrasive and corrosive materials. It is applied as a base coating to prevent cathodic disbonding.

It is used as a pump coating to reduce cavitation and erosion and to improve pump output. (For more on this topic, see Erosion Corrosion: Coatings and Other Preventive Measures.) It is also used to line aquaculture tanks and ponds and for canal repairs and leakage proofing.

What Application Methods are Best for Polyurea?

Four application methods are currently used:

  1. High-pressure hot spray

This method consists of:

  • Preparing the surface
  • Mixing the parts
  • Performing the coating application

The high-pressure method is chosen for very high-volume coating jobs. Formulators must prepare a lower viscosity coating at operating temperature to ensure a favorable flow of the fluid within the machine and a uniform thickness on the surface.

uring initial surface preparation, oily contaminants, and dirt must be removed by means such as abrasive sandblasting. Surfaces should be checked for cleanliness to ensure strong adhesion of the polyurea coating. This is a critical step to ensure the coating’s durability.

In the mixing stage the prescribed pressure and temperature range must be maintained. Component dosing and mixing must be done with precision. The spray system must be designed to maintain pressure as well as temperature.

The formulated mixture is sprayed on the clean de-dusted surface. The first coat is produced directly on the surface. A second coat is applied to ensure a leak-proof barrier. Machines used for polyurea spray coatings must be able to maintain temperatures up to 80°C (176°F) and pressure up to 210 bars.

  1. Warm spray coating

This method is chosen when the volume of the spray coating job is medium and formulators can ensure a low viscosity of fluid mix below 60°C (140°F).

  1. Low-pressure cold spray

In the case of cold spray, formulators must ensure low viscosity at ambient temperatures to enable spray coating. This is a convenient method for small surface area jobs and repairs.

Conclusion:

Polyurethane, due to its exceptional properties and versatility, has become an integral part of our daily lives, finding applications in various industries, including the Australian mining sector. Its unique attributes have made it highly sought-after for diverse uses, ranging from furniture and automotive parts to essential mining equipment. As technology and manufacturing processes advance, we can expect even more innovative applications of polyurethane in the future. With this comprehensive understanding, you can rest assured about its safety and wide-ranging benefits.

At Australian Mining Services, we offer a diverse range of polyurethane options tailored for quick turnarounds. Whether you require autoclave-cured hot-cast polyurethane or spray material, we have the perfect match to meet your site’s operational requirements while ensuring optimal performance. Our expertise and specialisation create products with specific hardness and physical properties perfectly aligned with your operational needs. Trust us to deliver the ideal solution for all your repair requirements!