Polyurethane Molding Manufacturers and Companies

Polyurethane Molding

Polyurethane molding is a specialized fabrication service provided by plastic parts manufacturers, offering a diverse range of production techniques, with injection molding being one of the most prominent. Utilizing polyurethane materials, manufacturers produce durable, flexible, and highly functional components suited for various applications. This process ensures precision, consistency, and adaptability, making it a preferred choice for industries requiring high-performance plastic parts.

The History of Polyurethane Molding

Molded polyurethane, often referred to as urethane or urethane rubber, is a polymer that combines the properties of both plastic and rubber, making it one of the most sought-after materials in the manufacturing industry. While its primary applications include flexible, rigid memory, and structural foam production, molded urethane is also widely used as a solid plastic, further enhancing its versatility in industrial applications.

Beginning of Polyurethane Molding

The polyurethane molding industry traces its origins back to 1939, when German chemist Otto Bayer successfully synthesized the first batch of polyurethane. This new synthetic polymer offered several advantages over plastics produced through the polycondensation of olefins. Initially, urethane was primarily used in fiber production, and during World War II, manufacturers applied it on a limited scale as a coating for aircraft.

Large-scale production of flexible and rigid memory foam, however, did not begin until polyisocyanates—the key ingredient in polyurethane—became commercially available. By 1952, this material was widely accessible, and polyurethane foam production quickly expanded. Through reaction injection molding with toluene diisocyanate and polyester polyol, manufacturers created not only foam but also elastomers (polymers with both viscosity and elasticity) and gum rubber. Over time, additional chemicals such as hexamethylene diisocyanate and butanediol were introduced to produce linear fibers.

Despite these advancements, early polyester polyols were expensive and lacked water resistance, prompting the industry to seek more cost-effective and durable alternatives. DuPont introduced polyether polyols, which soon gained popularity as other chemical producers followed suit, leading to more affordable foam production.

Advancements in Polyurethane Insulation

The availability of lower-cost polyols, methylene diphenyl diisocyanate, and a new blowing agent—chlorofluoroalkanes—ushered in the use of urethane for insulation materials. Polyurethane insulation proved to be highly effective, outperforming existing options and quickly gaining traction alongside foam production.

Introduction of Rigid Foam

The landscape of polyurethane manufacturing changed yet again with the advent of polyisocyanurate, which allowed manufacturers to produce thermally stable and fire-resistant rigid urethane foams. Recognizing its potential, the automotive industry adopted rigid urethane foam for interior components, such as door panels and instrumentation panels.

Polyurethane molding gained widespread recognition after a fully plastics car, featuring molded urethane parts, was showcased at an automotive exhibition in Germany. This demonstration highlighted how injection molding could be leveraged to produce various vehicle components. By incorporating additives such as mica, milled glass, and mineral fibers, manufacturers were able to enhance stiffness and improve thermal expansion resistance in molded urethane parts.

Rise of Resin Injection Molding

The evolution of polyurethane molding reached new heights with the development of resin injection molding, a process that integrates glass mats to enhance product durability. This advancement positioned urethane as a preferred material for producing an array of molded components, including urethane sheets, bushings, wheels, and conveyor wheels.

Today, both standard and custom polyurethane molding are more popular than ever. The durability, reliability, versatility, and cost-effectiveness of molded urethane continue to make it a preferred choice for manufacturers and customers alike. To further refine the molding process and enhance precision and repeatability, CNC technology has become a common tool in polyurethane production. CNC machining, which integrates computer-controlled technology into manufacturing, has revolutionized the industry by enabling greater accuracy, efficiency, and consistency in molded polyurethane products.

Benefits of Polyurethane Molding

Polyurethane molding offers numerous advantages, making it an excellent choice for a wide range of applications. Its versatility, durability, and cost-effectiveness set it apart from other materials and manufacturing processes. Let’s explore the key reasons why polyurethane molding is a preferred option.

Excellent Results

Polyurethane molding delivers highly accurate results, accommodating both intricate and large-scale part designs. It allows for rapid production cycles while enabling the formation of complex parts, including those with undercuts and no drafts, ensuring superior design flexibility.

Superior to Rubber

Polyurethane moldings surpass rubber components in several key areas. They offer superior resistance to abrasion, cuts, tears, oils, oxygen, ozone, and radiation, making them more resilient in demanding environments. Additionally, polyurethane parts exhibit a higher load-bearing capacity, a broader range of hardness options, and improved colorability, allowing for greater customization.

Superior to Metal

In applications where wear resistance is critical, polyurethane outperforms certain steel components. It provides enhanced resistance to abrasion, corrosion, and impact while maintaining flexibility and resilience. Unlike metal, polyurethane parts also offer better noise reduction properties, making them ideal for applications where sound dampening is essential.

Better than Regular Plastic

Molded polyurethane components outperform traditional plastic parts in numerous ways. They boast higher impact resistance, greater tolerance to extreme temperatures, and superior resistance to cold flow, radiation, and abrasion. Furthermore, their exceptional elastic memory, noise reduction capabilities, and overall resilience make them a superior alternative to standard plastic materials.

A Better Raw Material

Polyurethane is an incredibly adaptable material, offering a unique combination of properties. It is lightweight, easily moldable, non-conductive, and non-sparking, making it safe for various industrial applications. It also exhibits excellent adhesion, forming strong bonds with metals and plastics. Additionally, polyurethane provides thick section molding capabilities, low-pressure tooling advantages, and a naturally castable composition. Its inherent resistance to UV exposure and chemicals further enhances its durability and longevity.

Low Cost

Compared to rubber and plastic molding, polyurethane molding offers significantly lower tooling costs, making it an economical choice for both small and large production runs. The efficiency of the molding process contributes to reduced overall manufacturing expenses without compromising quality.

Little Waste

The polyurethane molding process generates little waste, as polyurethane materials can be reprocessed repeatedly without losing structural integrity. Any leftover or scrap material can be reused, reducing environmental impact and lowering material costs.

Low Maintenance

Polyurethane molded parts typically require little to no secondary finishing, streamlining production while reducing labor and material expenses. This efficiency ensures a faster time-to-market for finished products.

Stable Products

Urethane products maintain their hardness and structural integrity throughout their operational lifespan. Their stability ensures consistent performance in both static and dynamic applications, making them ideal for industries requiring long-lasting components.

Versatile Process

Polyurethane molding is an exceptionally versatile process. Manufacturers can produce foam components without external energy input, while also having the option to use heat to mold parts with specific physical and chemical properties. This adaptability allows for customized formulations that meet unique application requirements, providing limitless possibilities for innovative product designs.

With its unmatched durability, flexibility, and cost-efficiency, polyurethane molding stands as a superior manufacturing solution, delivering high-performance parts tailored to a wide range of industries and applications.

Materials Used in Molded Urethanes

Molded urethanes are derived from three primary classes of chemicals, each offering unique properties that enhance performance across various applications.

Polyester Based Urethane

Polyester-based urethane is highly compatible with polyvinyl chloride (PVC) and other polar plastics, allowing for effective blending that enhances material characteristics. The resulting compound exhibits superior resistance to oil and chemicals while significantly improving abrasion resistance. These properties make polyester-based urethane ideal for applications requiring durability in chemically aggressive environments.

Polyether Based Urethane

This class of urethane has a lower specific gravity compared to its polyester counterpart, making it a lightweight yet highly resilient material. It maintains flexibility at low temperatures while providing excellent tear resistance and abrasion durability. Additionally, polyether-based urethane is highly resistant to microbial attacks and hydrolysis, making it particularly well-suited for moist or humid environments where microbial degradation is a concern.

Polycaprolactone Based Urethane

Combining the best qualities of polyester-based urethane, polycaprolactone-based urethane offers exceptional toughness, abrasion resistance, and outstanding performance in low-temperature conditions. It also provides excellent resistance to hydrolysis, ensuring long-term reliability in demanding applications. These attributes make it a preferred choice for manufacturing pneumatic and hydraulic seals, where high wear resistance and durability are essential.

Each of these urethane types serves a distinct purpose, allowing manufacturers to tailor material selection based on the specific demands of their application.

Molding Process

Manufacturers employ a variety of techniques to create polyurethane moldings, with the most common methods including extrusion, compression molding, injection molding, and either open or closed urethane casting.

Before the molding process begins, manufacturers first create a master pattern and either a silicone or metal mold. They then gather the necessary raw materials, which, when combined, react to form a pre-polymer. During the urethane molding process, a curative is introduced to facilitate the polymeric transition. To prepare for molding, manufacturers bring the raw materials into a liquid state, ensuring easy mixing and precise measurement. Heat and/or pressure accelerate this transformation, turning the mixture into a fully liquefied form. At this stage, it is poured into a mold cavity, with some processes incorporating simultaneous mixing and colorization, a technique known as in-molding coating. Once the material has fully cured, it solidifies into its final polymer form and is removed from the mold.

In open polyurethane molding, the pre-polymer and curative are heated, mixed, and poured into an open cavity, where they cure without the application of pressure. In contrast, closed polyurethane molding methods such as injection molding involve heating and mixing the pre-polymer and curative before injecting them into a sealed mold cavity through small entry points. Each process is carefully selected based on the application’s requirements, ensuring optimal strength, flexibility, and precision.

Polyurethane Molding Types

Castable Urethanes

Elastomers containing urethane carbamate links, processed in liquid form, and exceptionally well-suited for casting applications.

Molded Urethane

Also known as molded polyurethane (PU), this elastic polymer, or elastomer, contains urethane carbamate links, making it highly durable and versatile.

Polyurethane Belts

Manufactured from an elastic polymer that contains urethane carbamate links, providing strength and flexibility for various industrial applications.

Polyurethane Manufacturers

Fabricators that produce molded urethane for a diverse range of products, utilizing advanced molding techniques.

Polyurethane Rods

Straight, uniform polyurethane products often circular or rectangular, though they can be molded into a variety of cross-sectional shapes for specific applications.

Reaction Injection Molding (RIM)

A specialized molding process similar to standard injection molding but exclusively used for thermosetting polymers, which cure in-mold. Common RIM materials include polyurethane, polyester, polyphenols, and polyepoxides.
In this process, manufacturers mix two polymer components under high pressure in an impinging mixer before injecting the blend into a mold at low pressure. Once inside the mold, the material expands and cures, forming strong, flexible, and lightweight parts. RIM is particularly valuable for creating thin-walled, large-scale components that are challenging to produce with other molding methods.

Room Temperature Vulcanization (RTV)

A subset of polyurethane molding, room temperature vulcanization (RTV) is a rapid prototyping and manufacturing process that enhances material durability through curative additions such as sulfur. Unlike traditional vulcanization, this method occurs at room temperature, making it ideal for small production runs where surface detail and functional precision are critical.
The most commonly used materials for RTV molding are silicone, wax, and polyurethane. The process provides a high level of detail, an exceptional surface finish, and the ability to withstand high temperatures up to 220ºF.

Rotational Molding

A molding technique where polymer material, such as polyester resin or powder, is poured into a hollow mold, which is then rotated in an oven until the resin melts and evenly coats the mold cavity. After cooling, the part is removed and treated like any other urethane mold component.
This process offers advantages such as consistent wall thickness, stress-free outer corners, low tooling costs, fast turnaround times, and exceptional design versatility.

Urethane Bumpers

Protective components designed to absorb shock and minimize impact damage in various applications.

Urethane Bushings

Specialized bearings used in automotive manufacturing as shock absorbers, ensuring proper alignment and suspension functionality.

Urethane Casting

A molding process similar to injection molding, but utilizing a soft mold instead of a hard one. The urethane casting mold, typically made from silicone, is often created using CNC machining or 3D printing for precision.
Cast urethane parts include skateboard wheels, molded bearings, urethane-covered rollers, and FDA-approved components. Manufacturers prefer urethane casting due to its ability to produce abrasion-resistant, temperature-resistant, and high-strength parts with excellent tear resistance.

Urethane Manufacturers

Experts in fabricating molded urethane, producing components for a wide variety of applications across multiple industries.

Urethane Molding

Also known as polyurethane molding, this process creates elastic polymers containing urethane carbamate links, offering superior flexibility, durability, and chemical resistance.

Urethane Sheets

Durable, long-lasting polyurethane sheets constructed from an elastic polymer, or elastomer, that contains urethane carbamate links, making them suitable for various industrial applications.

Urethane Wheels

Manufactured from molded polyurethane (PU), these wheels provide elasticity, shock absorption, and long-lasting wear resistance, making them ideal for transportation, industrial, and recreational applications.

Design and Customization of Polyurethane

When designing a polyurethane molded product, manufacturers take a comprehensive approach, evaluating a range of critical factors to ensure optimal performance. Beyond the product’s shape, when considering both standard and custom mold options, they assess various material properties that directly impact the application.

Tensile Strength

The tensile strength of a molded polyurethane product is determined by subjecting a specimen to stress over a defined period. A stress-strain diagram is used to record the deformation under applied stress, providing manufacturers with a clear understanding of how the material withstands tension and ensuring it meets the necessary strength requirements for its intended use.

Shore Hardness

This measurement determines a molded urethane product’s resistance to penetration and indentation, indicating whether the material is soft or rigid. By plotting a graph that compares flexibility and hardness, manufacturers can assess the balance between these two characteristics, ensuring the product performs as expected in its application.

Tear Strength and Compression Set

Tear strength evaluates how well a molded urethane product resists tearing forces, while compression set measures whether the material retains its original shape after compressive stress is removed. If a product has a high compression set, it may be permanently deformed after being compressed. Both measurements are essential for determining the durability and reliability of polyurethane components in demanding applications.

Polyurethane Blending

Beyond mechanical performance, manufacturers consider the physical and chemical properties of molded urethane materials. Factors such as abrasion resistance and shrinkage impact longevity, while exposure to acids, basic solutions, and hydrocarbons can weaken the product, causing swelling and reducing tear resistance. To enhance durability, manufacturers may blend polyurethane with additives that improve chemical resistance, creating a material that is better suited for harsh environments.

Custom Urethane Parts

For specialized applications, manufacturers offer custom urethane parts tailored to unique performance needs. Many provide extensive customization options, ensuring that material properties, design features, and application requirements align perfectly. Those interested in custom urethane molding can explore a manufacturer’s website, request a quote, or contact them directly to discuss project specifications.

Polyurethane Molding Applications

Polyurethane molding is a manufacturing process that produces products with a unique combination of desirable properties, including water resistance, chemical resistance, and protection against contaminants. These molded products also offer exceptional strength and flexibility, making them highly durable and adaptable to various applications.

Thanks to these advantageous characteristics, the polyurethane molding industry serves a broad spectrum of customers across numerous fields. Industries such as medicine and health care rely on polyurethane-molded components for hygienic and durable medical equipment. The construction sector benefits from its resilience and resistance to environmental conditions. Automotive manufacturers use molded polyurethane for parts that require impact resistance and longevity. In food processing, its non-toxic and contamination-resistant properties make it an ideal choice for various applications. Industrial manufacturing and engineering sectors integrate polyurethane-molded products into machinery and equipment for their ability to withstand harsh conditions. Additionally, sports and recreation industries take advantage of polyurethane’s flexibility and durability in equipment and protective gear. These industries, along with many others, continue to depend on polyurethane molding for its versatility and performance-driven advantages.

Products Produced Through Molding

Valued primarily for its role in both rigid and flexible "memory" foams, polyurethane also proves highly effective in solid plastic forms. It is widely utilized in the production of polyurethane rods, urethane sheets, urethane bushings, urethane tires, and urethane wheels, each offering exceptional durability, resilience, and adaptability for various applications.

Urethane manufacturers produce a diverse range of polyurethane moldings designed to meet specific industrial and commercial needs. These include an extensive selection of pneumatic seals, press tool blocks, electrical potting compounds, conveyor bushings, polyurethane belts, and urethane bumpers, all engineered for durability and performance. Beyond industrial applications, polyurethane is also molded into consumer and recreational products such as bowling balls and various specialty components, demonstrating its versatility across industries.

Manufacturers also utilize injection molding techniques to create high-performance urethane cushions. These cushions are designed for use in outdoor environments, aquatic applications, and the medical field, where they serve as therapy aids. In medical settings, urethane cushions help alleviate pain, enhance comfort, and improve patient endurance during exercise and rehabilitation. As the most commonly used form of cushioning for high-intensity applications, injection-molded cushion foam provides exceptional support and resilience. A molded urethane cushion can bear hundreds of pounds of weight while maintaining its structural integrity, springing back to its original dimensions with every use.

Things to Consider When Choosing Polyurethane Molding

If you’re considering investing in polyurethane molding services, partnering with an experienced and reliable polyurethane mold manufacturer is essential. While numerous suppliers offer polyurethane molding and related services, they vary in expertise, capabilities, and suitability for your specific needs. Not every manufacturer will be the right fit, so it’s crucial to take the time to find one that aligns with your expectations.

To ensure you select the best contract manufacturer, engage in detailed discussions with multiple polyurethane mold companies about your application. Clearly communicate your requirements and specifications, and assess whether they fully understand your needs. Confirm that they can accommodate your budget and timeline while maintaining high production standards. Most importantly, choose a manufacturer that prioritizes quality and is committed to delivering a superior solution tailored to your application.

Begin your search by exploring the many outstanding polyurethane mold manufacturers we have listed above. By doing so, you’ll be well on your way to finding the right partner for your project, ensuring efficiency, durability, and long-term success.

Polyurethane Molding Terms

Additive

An additional substance incorporated into a polymer to enhance its effectiveness without increasing its strength. Common additives include flame-retardants, anti-static urethane casting compounds, molded urethane pigments, and urethane molding lubricants.

Bloom

A discoloration that appears on the molded urethane surface of a polyurethane product. Unlike dust from external sources, bloom occurs due to the migration of a liquid or solid to the surface of the material.

Blowing Agent

A substance used to produce foam, such as carbon dioxide, which expands within the polymer to create a lightweight structure.

Breaking Strength

The maximum amount of tension polyurethane can withstand before rupturing during the urethane molding process.

Copolymer

A polymer composed of two distinct monomers, where each repeating unit in the polymer chain consists of molded urethane elements from both monomers.

Crosslinking

A chemical process that links polymeric chains together to create a three-dimensional network. Crosslinked polymers offer increased strength, durability, and resistance compared to linear polymers.

Cycle Time

The total duration required to complete a single urethane molding cycle, from initial mold preparation through demolding of the finished product.

Dam

A structural barrier placed within a urethane mold to control the flow of material. Dams are used to reduce, modify, or eliminate specific sections of the cast that were initially part of the mold design.

Demold Time

The time interval between the dispensing of liquid components into a urethane mold and the removal of the fully formed molded urethane product.

Diisocyanates

Chemical compounds, available in liquid or crystalline form, used in the manufacturing of polyurethane adhesives, coatings, and urethane casting foam.

Elastomer

A highly elastic material capable of stretching up to twice its original length at room temperature and then returning to its initial shape without permanent deformation.

Hydroxyl

An ion consisting of one oxygen atom and one hydrogen atom, commonly used in bases, acids, and alcohols for chemical reactions and bonding.

Hysteresis

The energy loss, typically in the form of heat, that occurs when an elastomeric material undergoes deformation due to applied urethane molding stress.

Micro Molding

A specialized urethane molding process that produces extremely small parts, measured in millimeters or microns. These micro-molded components require exceptionally tight tolerances and are widely used in industries such as biomedical, pharmaceutical, fiber optics, electronics, telecommunications, office automation, computing, and automotive manufacturing.

Monomer

The simplest unit of a polymer, typically existing as a liquid or gas. Monomers consist of molecules derived from the same organic substance and serve as the building blocks for polymer formation.

Polymer

A complex molecular structure formed by chemically bonding two or more monomers together in a repeating chain.

Polymerization

The chemical process in which monomers bond together to form a polymer, an essential step in the urethane molding production of polyurethane materials.

Polyol

A chemical compound containing two or more hydroxyl groups, which, when combined with diisocyanate, plays a fundamental role in producing polyurethane foam through urethane molding.

Polyurethane Casters

Durable, small wheels made of polyurethane, typically attached to an iron center and mounted onto a steel bracket. These casters are used across a wide range of industries, including healthcare, warehouse logistics, and material handling applications.

Polyurethane Motor Mounts

Engineered components used to secure a motor or transmission to a vehicle’s frame, providing stability and vibration dampening for improved performance and durability.

Resilience

A measure of an elastomer’s ability to absorb energy during deformation and then efficiently return to its original shape. The higher the resilience, the greater the material's ability to recover from impact and stress..

Thermoplastic

A category of plastics that can be repeatedly softened and reshaped when heated, then hardened again upon cooling. Unlike thermosets, thermoplastics retain their chemical composition throughout the urethane molding process, allowing for multiple reconfigurations.

Thermoset

A category of plastics that, once cured, become permanently rigid and cannot be reshaped upon reheating. Thermosets maintain their hardened structure indefinitely.

Urethane Molders

Urethane molding, or polyurethane molding, is an exceptionally versatile manufacturing process. Selecting the right urethane manufacturer is essential to ensure that all design specifications, material requirements, and application needs are met with precision and quality.