Choosing the Right Polymer for Your Injection Molded Oil and Gas Application

If you are involved in onshore, offshore, downhole, or subsea oil and gas operations, you understand the critical role plastics play. The oil and gas industry requires optimal performance from its equipment as it faces drastic temperature changes, harsh chemical contact, corroding seawater exposure, and inhospitable environmental conditions. This environment creates engineering challenges for equipment manufacturers. Fortunately, many engineering polymers have properties that can withstand these tough conditions.

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Materials Commonly Used in Oil and Gas Applications

Material selection is one of the most critical aspects in the design of oil and gas application components. Plastic and composite materials are increasingly used in various applications in the oil and gas industry due to their superior mechanical, chemical, and thermal properties. These materials can help reduce weight, increase corrosion resistance, and extend the lifespan of certain components, which can be beneficial in harsh environments. Nylon 6/6, glass-filled nylons, HDPE, TPU, glass-filled TPU, and acetal are commonly used for applications facing these challenging conditions.

Let’s look at each in more detail.

Nylon 6/6 (Polyamide 6/6 or PA 6/6)

Nylon 6/6 (polyamide 6/6) has a low coefficient of friction and good abrasion resistance. This tough material has high-temperature resistance, good chemical resistance, and excellent mechanical properties, making it ideal for applications such as gears, valve bearings, bushings, and structural parts. Nylon 6/6 can withstand the harsh conditions of the oil and gas industry, such as exposure to corrosive fluids, high pressures, and elevated temperatures.

Glass Filled Nylon

As the name says, glass-filled nylon is a nylon that has been reinforced with glass fibers. The addition of glass fibers improves the mechanical properties of the nylon, making it stronger and stiffer than nylon 6/6. Glass-filled nylon also has a higher resistance to impact and abrasion. It is used in applications where higher strength and stiffness are required. Glass-filled nylon is often used to manufacture components such as pump impellers, gears, and valves, where resistance to wear and abrasion is essential. Additionally, glass-filled nylon can provide electrical insulation, which is vital for electrical and electronic components in the oil and gas industry.

High-Density Polyethylene (HDPE)

Injection-molded HDPE can provide cost-effective solutions for oil and gas applications due to its low cost, high strength, and excellent resistance to chemicals, abrasion, and cracking. HDPE is commonly used to produce pipe fittings such as elbows, tees, and reducers. The material’s low coefficient of friction and resistance to wear and abrasion make it suitable for use in valves and pumps that are exposed to harsh chemicals and abrasive materials.

Thermoplastic Polyurethane (TPU) and Glass Filled TPU (TPU-GF)

TPU is said to combine the characteristics of rubber and plastics. It offers high durability, abrasion resistance, extended hydraulic stability, and flexibility even at low temperatures. Its resistance to most fuels, oils, and greases makes it ideal for gas and oil industry applications, like collars, seals and gaskets, pipe fittings, and electrical cable jackets and connectors.

TPU-GF contains glass fibers as a reinforcement material. The properties of TPU-GF can vary depending on the type, concentration, and orientation of the glass fibers, as well as the TPU matrix used. However, the addition of glass fibers to TPU generally results in a composite material with enhanced mechanical, thermal, and electrical properties. The glass fibers act as a barrier to heat transfer, reducing the coefficient of thermal expansion and improving the material’s dimensional stability over a wider temperature range. These advanced properties lend themselves to better performance in harsh environments with applications such as pump impellers, valve components, and pipe fittings.

Acetal

Acetal is a high-performance plastic that offers good mechanical strength, high stiffness, low friction, and excellent wear and abrasion resistance. It is beneficial for use in the oil and gas industry because it can maintain its shape when exposed to heat and pressure. It is commonly used in applications that require dimensional stability, such as gears, bearings, and bushings.

Acetal’s excellent chemical resistance to a range of fluids and gasses, including hydrocarbons and natural gas, makes it a smart choice for valve seats, pump impellers, and seals. Its low moisture absorption and high dimensional stability make it a suitable material for applications that require tight tolerances and precise positionings, such as valve and pump components.

Working With Plastic Injection Molding Experts

When choosing a suitable material for your application, it is essential to consult with a qualified engineer or material specialist. Noble Plastics’ Engineering team can provide guidance on material selection and let you know if injection molding is right for your application.

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