Urethane Casting Resins

Soft to rigid elastomers for tooling, low-volume production, and prototyping

About Urethane Casting Resins

PTM&W urethane casting products are two-part systems designed for tooling and production and prototyping applications. Durometers range from 40 Shore A to 85 Shore D.

Urethanes for tooling are grouped into 5 categories divided by hardness and related end uses.

Soft urethane elastomers for tough, flexible tooling and molds are generally 50 Shore A Hardness and under, and are ideally suited for applications such as bumpers, pads, and flexible molds or soft parts where a high degree of flexibility & toughness is required. Their relatively high tensile strengths make them good performers for masking or holding fixtures where the tooling needs to be stretched to apply and remove.

Mid-range hardness urethanes for high strength tooling and molds are tough elastomeric urethanes that are generally in the 60 - 80 Shore A hardness range. They perform very well in light metal forming dies such as brake form pads. Their slightly tougher nature, compared to softer materials, makes them ideal for applications such as very tough high strength flexible molds, and they produce durable, abrasion resistant shapes and parts, cutting pads, fixtures, and flexible parts.

Hard elastomeric urethane tooling materials range in hardness from Shore A 90 to Shore D 60, and are work horse metal forming materials. They are also used extensively in the foundry, where they are capable of outlasting metal patterns in many applications. Shore A 90 and Shore A 95 urethane systems are harder flexible elastomers with very tough cured properties that make excellent metal forming tooling and are useful in many other demanding industrial applications. Forming dies, die springs, stripper pads, patterns, gears, and tough parts are all applications in which these hard elastomers excel. Shore D 60 urethane systems are exceptionally tough, hard elastomers, that have cured characteristics which make them well suited for some very demanding industrial uses.

Rigid urethane elastomers are very hard systems (75 Shore D and harder), are plastic-like in appearance, yet provide the inherent toughness and durability of engineering elastomers. They work very well in tooling applications such as patterns, molds, and fixtures. They are ideal for the fabrication of high strength rigid parts such as seals, bushings, and prototype items.

REPLICAST fast setting tooling urethanes are a line of products consisting of hard, rigid, fast setting general purpose urethane systems for the rapid production of temporary and short-run tooling, various jigs and fixtures, as well as rigid, durable shapes and parts.

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Formulations vary by manufacturer, brand, and grade. Ask your Curbell Plastics representative for more specific information about an individual option or brand.

Urethanes for Production and Prototyping

The epoxy and polyurethane products listed in this section combine ease of handling with superior cured physicals to provide production and prototype parts with many beneficial properties. The proper choice from these products will allow the user to duplicate the properties of a number of engineering plastics with low-cost tooling in a very short time. They cover a broad range of applications, and include high performance materials with outstanding properties and toughness, materials for clear casting, and those with excellent fire retardant systems. A few of these products are certified to the UL 94 V-0 flame retardant specification, and our PT8902 is certified to USP Class VI requirements.

This Product Line Consists of The Following Types of Products:

High impact and clear systems
Materials for hand-cast and vacuum cast applications
Twin-tube and machine dispense materials
Fire retardant rigid systems for production and prototypes
Flexible urethanes for production and prototype uses

TOOLING URETHANE CASTING RESIN OPTIONS

Soft Urethane Elastomers

Mid-Range Hardness Urethanes

PT7260 Kit 2 Part (Shore A-60, amber)– this Shore A-60 urethane system is a tough elastomeric material in the middle range hardness for flexible urethanes that have good handling and cured properties. Its slightly tougher nature, compared to softer materials, makes it ideal for applications such as high strength flexible molds, abrasion resistant shapes and parts, cutting pads, fixtures, and flexible parts. With its more rapid gel time (compared to PT7256), it is especially useful for smaller parts, as it will gel and cure adequately in those smaller masses. It is light colored, releases air very well, and pours easily. PT7260 is a clear system so it can be tinted with either transparent or opaque dyes or pigments for a variety of colored castings. For those times when a heat cure is not possible, the PT7260 will cure faster than PT7265 with just a room temperature cure cycle.

PT7265 Kit 2 Part (Shore A-65, amber)– has a little higher mixed viscosity, but it has a longer working time than PT7260, so it will still fill even complicated molds with no problems. The longer working time means that PT7265 can be used to pour larger masses and still have acceptably low shrinkage. PT7265 has 50% more elongation than the PT7260, so it will perform very well in applications where maximum stretch and elongation is required. PT7265 is a clear system so it can be tinted with either transparent or opaque dyes or pigments for a variety of colored castings.

PT7275 Kit 2 Part (Shore A-75, amber)– Shore A-75 urethane system is a tough elastomeric material in the middle range hardness for flexible urethanes that have good handling and cured properties. Its slightly tougher nature, compared to softer materials, makes it ideal for applications such as metal forming dies, high strength flexible molds, abrasion resistant shapes and parts, cutting pads, fixtures, and flexible parts. PT7275 is a light colored material that releases air very well and pours easily. It is very clear so it can be tinted with either transparent or opaque dyes or pigments for a variety of colored castings.

PT7275 Part A (Shore A-75, amber)– urethane is a middle range hardness elastomer. Sold separately, Part A requires the PT7275 Part B hardener. It is ideal for applications such as metal forming dies, high strength flexible molds, abrasion resistant shapes and parts, cutting pads, fixtures, and flexible parts. PT7275 is a light colored material that releases air very well and pours easily. PT7275 is very clear so it can be tinted with either transparent or opaque dyes or pigments.

PT7275 Part B (Shore A-75, amber)– hardener for PT7275 Part A.

Hard Elastomeric Urethanes

PT7290 Kit 2 Part (Shore A-90, amber)– Shore A-90 urethane system is a hard flexible elastomer with very tough cured properties that make excellent metal forming tooling, and is useful in many other demanding industrial applications. Forming dies, die springs, stripper pads, patterns, gears and tough parts are all applications in which this elastomer excels. It has a low mixed viscosity and a long pot life, so it is very well suited to pouring into closed molds, where it easily fills thin cross sections, and flows through thin pouring spouts readily. It is low in color and accepts dyes or pigments easily when tinted castings are required.

PT7290 Part A (Shore A-90, amber)– Shore A-90 urethane system is a hard flexible elastomer with very tough cured properties that make excellent metal forming tooling, and is useful in many other demanding industrial applications. Sold separately, Part A requires the PT7290 Part B hardener. Forming dies, die springs, stripper pads, patterns, gears and tough parts are all applications in which this elastomer excels. It has a low mixed viscosity and a long pot life, so it is very well suited to pouring into closed molds, where it easily fills thin cross sections, and flows through thin pouring spouts readily. It is low in color and accepts dyes or pigments easily when tinted castings are required.

PT7290 Part B (Shore A-90, amber)– hardener for PT7290 Part A.

PT7660 Kit A/B (Shore D-60, amber)– Shore D-60 urethane system is an exceptionally tough, hard elastomer that has cured characteristics which make it well suited for some very demanding industrial uses. This system has a very high tensile and tear strength and excellent elongation, so tooling or parts made with this material are very durable. PT7660 has very good resistance to abrasion, so it is ideal for the production of foundry tools and patterns. The almost 30 minute working time combined with its low mixed viscosity allows PT7660 to be used in both open casts and closed molds. Its curing time allows quicker production of multiple-piece patterns and smaller castings.

Rigid Urethane Elastomers

REPLICAST Fast-Setting Urethane Tooling System

PRODUCTION AND PROTOTYPING URETHANE OPTIONS

High-Impact and Clear Materials

Materials for Machine Dispense and Hand Pour Applications

PT8907 A/B Kit (black)– is a low viscosity, modified polyurethane system designed for machine dispensing applications for the fast, efficient production of tough, durable, castings and parts. It has a low mixed viscosity which allows easy mold filling into thin sections with low pressure. It develops strength very quickly, and allows fast demold times for more cycles per day. The cured material is very tough and can be demolded without fear of breakage. It is not brittle in thin sections. The heat resistance of PT8907 is very good. It has a high heat distortion temperature—even with only a room temperature cure. A much broader range of part types can be considered with PT8907, as it will withstand exposure to heat better than other materials of this type. PT8907 has very high heat resistance—glass transition temperature is 326°F.

PT8907 Part A (black)– is a modified polyurethane system designed for machine dispensing applications for the fast, efficient production of tough, durable, castings and parts. It has a low mixed viscosity which allows easy mold filling into thin sections with low pressure. It develops strength very quickly, and allows fast demold times for more cycles per day. Sold separately, Part A requires the PT8907 Part B hardener.

PT8907 Part B (black)– hardener for PT8907 Part A.

PT8908 Kit A/B (black)– is a low viscosity, modified polyurethane system designed for machine dispensing applications for the fast, efficient production of tough, durable castings and parts. This system is a modification of our PT8907, and has a longer pot life with lower viscosity, to allow the casting of larger parts. It has a low mixed viscosity which allows easy mold filling into thin cross-sections with low pressure. It develops strength very quickly, and allows fast demold times for more cycles per day. The cured material is very tough and can be demolded without fear of breakage. It is not brittle in thin sections. The heat resistance of PT8908 is very good, therefore, a broad range of part types can be considered with PT8908, as it will withstand exposure to heat better than other materials of this type. PT8908 is a tougher, more versatile product than previously available materials for this application.

PT8948 Kit 2 Part (natural translucent)– is a hard rigid urethane designed specifically for hand pouring or mechanized casting of larger parts. This product has a volumetric mix ratio of 1:1 which will allow convenient dispensing through twin-tube mixers. The very low mixed viscosity allows easy vacuum degassing, and makes it readily pourable into complicated molds, where it provides good reproduction of fine details. PT8948 cures to a translucent solid and can be easily colored. This system has a quick demolding time in relation to its working time. The material reaches full properties with a room temperature cure to a hardness of 80-82 Shore D. PT8948 is ideal for casting prototypes to simulate molded parts, proof testing of injection molding cavities, industrial models, holding fixtures, and high performance production parts. Pot life 6 minutes.

PT8949 Kit A/B (white)– is a hard rigid urethane designed specifically for hand pouring or mechanized casting of larger parts. This product has a volumetric mix ratio of 2:1 which will allow convenient dispensing through twin-tube mixers. The very low mixed viscosity allows easy vacuum degassing, and makes it readily pourable into complicated molds, where it provides good reproduction of fine details. PT8949 cures to a brilliant opaque white and can be easily colored since no pigments are incorporated into it. This system has a quick demolding time in relation to its working time. The material reaches full properties with a room temperature cure to a hardness of 70-75 Shore D. PT8949 is perfect for casting prototypes to simulate molded parts, proof testing of injection molding cavities, industrial models, holding fixtures, and high performance production parts. Pot life 5-5 1/2 minutes.

PT8949 Kit A/B1 (white)– is a hard rigid urethane designed specifically for hand pouring or mechanized casting of larger parts. This product has a volumetric mix ratio of 2:1 which will allow convenient dispensing through twin-tube mixers. The very low mixed viscosity allows easy vacuum degassing, and makes it readily pourable into complicated molds, where it provides good reproduction of fine details. PT8949 cures to a brilliant opaque white and can be easily colored since no pigments are incorporated into it. The material reaches full properties with a room temperature cure to a hardness of 70-75 Shore D. Perfect for casting prototypes to simulate molded parts, proof testing of injection molding cavities, industrial models, holding fixtures, and high performance production parts. Pot life 11-12 minutes.

Fire Retardant Materials

Flexible Urethane Systems for Prototype Parts

Tech Tip– Generally, with polyurethane elastomers, full properties are developed in 7 days at room temperature (75°F). Temperatures below 75°F will lengthen the cure time, and if the ambient temperature is below 60°F, additional heat may be necessary for proper cure. Elevated temperatures will accelerate the cure of urethanes, but care must be taken if a higher temperature is used to cure the material. Generally, the higher the curing temperature, the greater the final cured shrinkage. When heat curing for more rapid processing, to best control shrinkage, the casting should be allowed to set for 12 to 18 hours at room temperature before an oven post cure. A typical accelerated curing cycle, therefore, would be: Allow to gel on the pattern for 12 to 18 hours at room temperature (70°F to 80°F), then post cure for a minimum of 8 hours at 150°F to 165°F and allow to cool before demolding.