Continuous Fiber Reinforced Inserts for Large Flat PP Parts
Selective PP reinforcements from Integrated Composite Products (ICP) offer significant improvements in strength, stiffness and impact properties.
Continuous fiber reinforced inserts for large flat PP parts that are said to offer mechanical engineers lightweight options with significant improvements in strength, stiffness and impact properties while only adding pennies to the overall part cost have been developed by Integrated Composite Products (ICP), Winona, Minn. Founded in 2013, ICP is an innovative developer of low-cost, lightweight long and/or short fiber composite materials with several patents under its belt. Among the newest developments are the company’s new thermoplastic Tension Members (TM), which are essentially continuous glass reinforced PP rods or inserts for PP application in injection molding and/or compression molding. Typical applications targeted include boards, scaffolding, bins, shelving, pallets, bumper beams, seatbacks, tailgates, and other similar large structures.
Director of product development Robert Wick confirms that the rods are produced with a pultrusion process, that the company is targeting essentially flat PP parts with “a slight bend at most”, and that the company is also working on their application with other thermoplastics. He notes that this is because the TMs can be dropped right into the mold without first “shaping” them, which is an added cost. “Many applications have customers adding metal rods or thermoset inserts in order to get the strength and stiffness that they are looking for. If a metal or thermoset rod is used, then the parts are not recyclable unless these inserts are taken out. In addition, metal and thermoset inserts are usually much more expensive than $.061 per foot with our technology.”
The TMs are inserted in the mold and strategically placed at the bottom of a molded rib before PP is injected. “When a molded part is stressed, it normally fails at the bottom of the rib. By placing these “rods” directly to the bottom of the rib, the force is distributed across the entire rib; thus, dramatically increasing the load capacity and overall stiffness of the molded part.”
In injection molded 5-in. wide by 18-in. long by 1-in. deep panels processed in 40% long fiber glass filled (LFT) PP, using the company’s patented technology has been shown to provide flex strength improvements of 72% and flex modulus improvements of 21% without increasing any of the part weight. In compression molded 8-in. wide by 18-in. long by 1-in. deep panels using the same 40% LFT PP, the property improvements have been shown to be even greater obtaining flex strength improvements of 142% and flex modulus improvements of 50%, again not impacting the part weight.
According to Wick, TMs are manufactured and sold based on the number of glass filaments within the TM and the overall length of TM. “For example, an 8,000 filament (i.e. 8,000 individual strands of fiber) product has an overall diameter of .090-in. round and sells for around 3.4¢/ft at high volume. A 12,000 filament product is .160-in. in diameter and sells for approximately 6.1/¢/ft at high volumes. ICP can vary the number of filaments in the TM to meet the application needs and rib size,” he explains.
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