RTP launches cellulose fiber-reinforced PP compounds

Thermoplastics compounder RTP Company (Winona, MN) has unveiled the latest addition to its Eco Solutions product portfolio with a new line of custom cellulose fiber reinforced polypropylene (PP) compounds. These compounds, which utilize Thrive renewable cellulose fibers from forestry, wood product, and paper packaging giant Weyerhaeuser (Longview, WA), will reportedly facilitate the design and production of environmentally friendly products by providing favorable performance and economics to a wide range of durable applications.

"[Our] new cellulose fiber reinforced PP compounds overcome many of the obstacles that have hindered the adoption of bio-based resins and natural fiber compounds," says Will Taber, Business Manager - Emerging Technologies at RTP. "They will allow product developers to meet consumer demand for environmentally friendly products that are highly functional yet cost effective. Additionally, they can help processors and OEMs to meet their sustainability objectives by reducing processing costs. On multiple fronts these new compounds provide an unmatched advantage."

Cellulose fibers can be incorporated into PP as reinforcement to provide increased strength, stiffness, and thermal performance making these compounds suitable for structural applications while providing sought-after eco-friendly, renewable content.

In comparison to other natural fibers like wood, hemp, and sisal or natural fillers like wood flour and wheat straw, cellulose fiber reportedly provides higher strength and stiffness, consistent color, superior processability, low odor, and a reliable supply.

Advantages cellulose fiber has over glass fiber as reinforcement in PP are said to include: renewable content to meet sustainability objectives, lower energy consumption during processing, specific gravity reductions of 6-9% at like loadings, average cycle time reductions up to 30% for medium- to thick-walled parts, and reduced tool wear.

Compared to unreinforced PP, a homopolymer PP with 20% cellulose fiber reinforcement offers a 38% increase in tensile strength, a 75% boost in flexural modulus, and a 60°F rise in heat deflection at 66 psi (16°C at 455 kPa). Cellulose fiber-reinforced PP compounds from RTP Company also offer strength and stiffness that is comparable to uncoupled glass fiber-reinforced PP and achieves approximately 75% of the performance of a chemically coupled glass fiber-reinforced PP.

Cellulose fiber can also be combined with glass fiber or impact modified copolymer for materials that meet requirements of more demanding applications. These compounds can also incorporate post-consumer recycled PP to maximize their eco-friendly content. Additionally, they are fully colorable, can be overmolded with select RTP Company thermoplastic elastomers to enhance application ergonomics, and are available worldwide from RTP Company's global network of full-service facilities that provide technical support from design through finished part production.

Cellulose fiber-reinforced PP compounds have potential uses in a variety of structural injection molded parts including bezels, bases, brackets, knobs, handles, lids, and housings for the automotive, appliance, furniture, lawn and garden, sporting goods, and toy markets.

Weyerhaeuser itself also markets PP compounds employing its cellulose fibers under the Thrive DX Series. Cellulose fiber loadings of 10-40% are possible, blended with virgin or recycled PP and compatibilizer. MFIs range between five and 35.