Polyurethane Compound produces lightweight molded parts.

Press Release Summary:



Suited for decorative and structural uses, Stonecast® can replace wood, fiberglass, and metal in indoor and outdoor applications. It can be attached to metal, concrete, and wood without expansion/contraction problems, warpage, or cracking. Material may be painted, stained, sanded, and drilled. Parts up to 200 lb can be hand-poured and demolded in 10-20 min. Stonecast is suited for continuous temperatures of 150°F, and maintains shore D hardness of 68 at 200°F.



Original Press Release:


Arnco Develops Advanced Polyurethane Engineered for Production of Decorative & Structural Molded Products


South Gate, CA - The first urethane molding compound to meet the dimensional stability, weather ability and design requirements for exterior decorative and structural applications has been developed by the Performance Polymers Group of Arnco.

"Imagine the possibilities," said Arnco President, Larry Carapellotti, in announcing the patent-pending Stonecast® system that expands the use of polyurethane into applications never before possible with other materials. "This unique product," he added, "has the lowest coefficient of thermal expansion of any urethane molding compound currently available. It is formulated to produce lightweight molded parts that can replace wood, fiberglass and metal in virtually an unlimited number of indoor and outdoor applications. Most importantly," he continued, "it can be attached to metal, concrete and wood without concern for expansion/contraction problems, warpage or cracking over a wide range of temperatures.

"Stonecast," he concluded, "is expected to create a major market for such indoor and outdoor applications as architectural elements, signage, countertops, furniture, marine applications, fireplace surrounds, commercial planters/pottery, outdoor fountains/statuary and faux stone/granite."

The new elastomer also has a great balance of properties to offer in decorative and structural applications that require exceptional surface appearance, durability, weather ability, heat resistance, volume production, low toxicity, good impact strength and design flexibility.

According to General Manager, Jack Tatum, and Technical Director, Steve Lucka, of Arnco's Performance Polymers Group, Stonecast can be easily painted, stained, sanded and drilled, and does not require expensive equipment for processing. It can be used to produce one-piece finished products, which will replace parts that now use multi-components. It also can be used with a variety of in-mold or post-finish coatings to obtain UV stability. One of Stonecast's most unique capabilities allows the customer to choose almost any surface appearance or design - from a broad range of stone and granite looks to wood-grain, metallic and brick.

The new elastomer can be used at 100 percent solids, or with a variety of fillers to achieve specific properties and/or lower cost. It has an exceptional strength-to-weight ratio when used with Arnco's proprietary filler, with finished parts having specific gravity of 0.9. This is approximately the weight of most hardwoods. Stonecast is also engineered to generate less than 0.1 percent in-mold shrinkage. Stonecast molded parts will reproduce minute mold detail exactly, and will maintain their original shape without distortion after demold. Large parts (up to 200 pounds) can be hand poured and demolded in 10-20 minutes.

Because Stonecast has the lowest coefficient of thermal expansion of any urethane casting resin, pieces made with the system can be used in high heat or outdoor conditions without concern for warpage or cracking. With most urethane resins, a 10-foot long part will expand over one-and-a-half inches when going from 0°F to 140°F. The same part made from Stonecast will move less than one-half inch over the same temperature range.

Stonecast can be used at continuous temperatures of 150°F, and maintains a shore D hardness of 68 at 200°F. Many conventional casting resins fail at 140°F or lower.

Founded in 1971, Arnco has become one of the world's largest suppliers of polyurethane products. With its extensive experience and technical know-how, the Performance Polymers Group continues to develop an increasing range of urethane systems. These currently include high hardness molding compounds, rigid and flexible foams, cast elastomers, spray elastomers, primers and MDI and TDI prepolymers.

For additional information, call 323-249-7500 or visit the Arnco website at www.arnconet.com.

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