Polyurethane Molding

About Polyurethane Molding and Polyurethane Molding Services Including: Molded Urethane, Polyurethane Manufacturers, Urethane Bushings, Urethane Casting, Urethane Manufacturers, Urethane Molding, Urethane Sheets & Urethane Wheels.

Polyurethane molding, also called urethane molding, is an elastic polymer, or elastomer, containing urethane carbamate links. From a molten liquid state, polyurethane may be fabricated or molded into low-density flexible foam, low-density rigid foam, soft solid elastomers (gel) and hard solid plastics. Valued primarily for its uses in rigid and flexible "memory" foams, polyurethane is extremely useful in solid plastic form as well. Polyurethane molding combines many of the desirable qualities of plastic, rubber and metal with longer service life than plastics, higher impact resistance than rubber, elastic memory, noise reduction, heat and chemical resistance, and many other properties. For this reason, polyurethane manufacturers fabricate molded urethane into high-impact urethane wheels for casters, urethane sheets for prototyping and a wide variety of urethane castings such as rollers, gears, bushings, bumpers, sprockets and parts for a broad spectrum of industries.

Industries that utilize polyurethane molding services include the construction, engineering, automotive, food processing and athletic equipment. Parts as diverse as bowling balls and conveyor bushings are fabricated by urethane manufacturers. Applications in the automotive industry include cellular suspension units, press tool blocks, grommets, bearings and shock absorber bushes. Polyurethane is useful to the mining, quarrying and civil engineering industries in applications such as rope pulley linings, conveyer belt scraper blades, abrasion resistant strips and hydraulic seals. The textile industry uses molded polyurethane parts for knitting machine falling bars, yarn feed rollers, loom pickers and machine couplings. Molded polyurethane parts, such as conveyer rollers, pressure pads and pneumatic seals and buffers, are also valuable in the mechanical handling of products. Molded polyurethane parts are utilized in the footwear and shoe industry, as well, for stiletto heel tips, soling materials, heel molding pads and drive rollers.

The raw materials of polyurethane exist in a liquid state, which allows for easy mixing and measuring in preparation for molding, which may be open casting or closed casting. Raw materials react with one another to form a pre-polymer, then during the polyurethane molding process, a curative is introduced to the pre-polymer in order to complete the polymeric transition. Accelerated by heat and/or pressure, the mixture is poured into a mold cavity and cured to form the final polymer. During open polyurethane casting, the pre-polymer and curative are heated and mixed together, poured into an open cavity and cured without the application of pressure. Compression polyurethane molding is commonly used to make small polyurethane parts such as gears.

Although all elastomers maintain strength and versatility in many industrial applications, polyurethane elastomers possess several advantages over other elastomers and materials. Urethane has higher abrasion, cut, tear, oil, ozone and radiation resistance, greater load bearing ability, broader hardness range and better colorability than rubber. Polyurethane also has thick section molding and low pressure tooling capabilities and a castable nature. As compared to metal, polyurethane has better noise reduction and resilience, greater abrasion, corrosion and impact resistance, more flexibility and is less costly to fabricate. Polyurethane is also lightweight, easily moldable, non-conductive and non-sparking. Polyurethane serves better than regular plastic in many applications, as it has higher impact, low temperature, cold flow, radiation and abrasion resistance, better elastic memory and noise reduction capabilities, greater resilience and provides lower cost tooling. The cost of polyurethane molding is on par with the cost of rubber and typical polymer molding, giving urethane an economic advantage as well.

Polyurethane Molding and Polyurethane Molding Services Image Provided by FallLine Corporation

Polyurethane Molding and Polyurethane Molding Services Image Provided by Weaver Industries, Inc.	Polyurethane Molding and Polyurethane Molding Services Image Provided by American Urethane, Inc.

Polyurethane Molding Types

• Cast urethanes, also known as "RTV molding" or "polyurethanes," refer to a production method in which polyurethane plastic material is produced in low volumes for marketing samples, test prototypes or other applications that require less than 100 pieces but where time and money does not allow for the injection molding process.
  
• Injection molded urethane is highly durable and easily painted.
  
• Molded urethane is a plastic product that has been formed with dyes.
• Polyurethane manufacturers make various products made out of polyurethane.
• Polyurethane molding uses the tool and dye process to make components out of polyurethane.
• Polyurethane sheets are hard but flexible sheets that outperform metals in many applications. Polyurethane sheets retain their flexibility even at low temperatures.
  
• Polyurethane wheels have a hardness that is similar to that of phenolic, polyolefin, hard rubber and other hard tread wheels, but are not noisy.
• Urethane casting is an elastic polymer, or elastomer, containing urethane carbamate links.
• Urethane manufacturers make various products out of urethane.

Polyurethane Molding Terms

Additive - Substance added to a polymer to increase the effectiveness, but not the strength, of the polymer. Examples of additives include flame-retardants, anti-static urethane casting compounds, molded urethane pigments and urethane molding lubricants.
 
Bloom - A discoloration of the molded urethane surface of a polyurethane product-not to be confused with dust from external sources-caused by the migration of a liquid or solid to the surface.
 
Blowing Agent - Foam producing substance (e.g. carbon dioxide).
 
Breaking Strength - The point of tension at which polyurethane will rupture in urethane molding process.
 
Copolymer - A polymer made up of two monomers in which each repeating unit in the chain consists of molded urethane units of both monomers.
 
Crosslinking - The chemical linkage of polymeric chains that results in a three-dimensional network of polymers. Crosslinked polymers possess greater strength and durability than linear polymers do.
 
Cycle Time - The amount of time necessary to complete a urethane molding cycle from urethane mold preparation to demolding.
 
Dam - A device placed within a urethane mold that prevents the flow of material into cavities of the mold in order to reduce, alter or eliminate a part of the cast for which the urethane mold was initially designed.
 
Demold Time - The amount of time that passes between the dispensation of liquid components into the urethane mold and the removal of the end molded urethane product.
 
Diisocyanates - Chemicals in liquid or crystalline form used in the production of polyurethane adhesives, coatings and urethane casting foam.

Elastomer - A material capable of returning to its initial length after being stretched at room temperature up to twice its original length.
 
Hydroxyl - An ion, composed of one oxygen atom and one hydrogen atom, used in bases, acids and alcohols.
 
Hysteresis - Energy loss in the form of heat that results from the deformation of elastomeric material caused by the application of urethane molding stress.
 
Micro Molding - The forming of millimeter- or micron-sized parts through the urethane molding process. Micro molded parts, for which tolerances must be extremely tight, are increasingly in demand by biomedical, pharmaceutical, fiber-optic, electronics, telecommunications, office-automation, computer and automotive industries.
 
Monomer - The most basic polymeric unit, usually a liquid or a gas, consisting of molecules from the same organic substance.

Polymer - Two or more monomers bonded together in a chain through a chemical reaction. 

Polymerization - The urethane molding process in which a chemical reaction links together monomers to form a polymer.
 
Polyol - A chemical compound composed of two or more hydroxyl groups that, in conjunction with diisocyanate, are used in the urethane molding production of polyurethane foam.
 
Resilience - The comparison of the amount of energy needed to create an elastic deformation and the amount of energy needed to recover from such a deformation.
 
Thermoplastic - Category of plastics that have the potential to soften and reform when heated, hardening again when cooled. During the urethane molding process, the physical makeup of the thermoplastic does not change.
 
Thermoset - Category of plastics that cannot be reformed upon reheating. Thermosets remain permanently hard.