Fiber rovings have been employed in a wide variety of applications. For example, such rovings have been utilized to form fiber-reinforced composite rods. The rods may be utilized as lightweight structural reinforcements. For example, power umbilicals are often used in the transmission of fluids and/or electric signals between the sea surface and equipment located on the sea bed. To help strengthen such umbilicals, attempts have been made to use pultruded carbon fiber rods as separate load carrying elements.
Another application that is particularly suited for the use of fiber rovings is in the formation of profiles. Profiles are pultruded parts with a wide variety of cross-sectional shapes, and may be employed as a structural member for window lineals, decking planks, railings, balusters, roofing tiles, siding, trim boards, pipe, fencing, posts, light posts, highway signage, roadside marker posts, etc. Hollow profiles have been formed by pulling (“pultruding”) continuous fiber rovings through a resin and then shaping the fiber-reinforced resin within a pultrusion die.
Further, fiber rovings may generally be utilized in any suitable applications to form, for example, suitable fiber reinforced plastics. As is generally known in the art, rovings utilized in these applications are typically combined with a polymer resin.
There are many significant problems, however, with currently known rovings and the resulting applications that utilize such rovings. For example, many rovings rely upon thermoset resins (e.g., vinyl esters) to help achieve desired strength properties. Thermoset resins are difficult to use during manufacturing and do not possess good bonding characteristics for forming layers with other materials. Further, attempts have been made to form rovings from thermoplastic polymers in other types of applications. U.S. Patent Publication No. 2005/0186410 to Bryant, et al., for instance, describes attempts that were made to embed carbon fibers into a thermoplastic resin to form a composite core of an electrical transmission cable. Unfortunately, Bryant, et al. notes that these cores exhibited flaws and dry spots due to inadequate wetting of the fibers, which resulted in poor durability and strength. Another problem with such cores is that the thermoplastic resins could not operate at a high temperature.
Still further, the impregnation dies utilized to impregnate rovings with polymer resins may have various problems. For example, in many impregnation dies, a waveform impregnation section is utilized to impregnate the rovings. However, in many impregnation sections, the outermost rovings may snag on or be otherwise disrupted by the edges of the impregnation sections. Other impregnation sections may utilize sidewalls in an attempt to prevent snagging. However, the sidewalls of such impregnation sections may allow resin to flow thereon. This resin can build up, harden, and then move back into the main impregnation zone of the impregnation section, disrupting the rovings therein.
As such, a need currently exists for an improved impregnation section for impregnating a fiber roving. Specifically, a need currently exists for an impregnation section that prevents roving snagging and resin build-up while producing fiber rovings which provide the desired strength, durability, and temperature performance demanded by a particular application.
USPTO Backgrounds
USPTO Backgrounds