Patent NZ-706905-A (NZ)
Title: Wallboard corner finishing strip
Inventor: ROSENTHAL GUY
IPC: E04F13/06
Filed: 2013-09-19
Abstract: Corner beads finish a rough corner into a pleasing symmetrical transition with the respective adjoining walls, and also provide some resistance to abuse and impact on the corner. To accomplish these tasks, a suitable corner bead product should fit snugly on the wall, be easy to attach, and have material and design properties that allow it to resist at least minor impacts without severe damage or detachment from the wall. Conventional corner bead strips are either made of metal or various types of plastic, and are provided in relatively rigid lengths or in flexible rolls. Flexible corner bead strips are typically two types. In the first type, 2 metal strips approximately 0.010-0.015 inch (0.025-0.038 cm) thick are disposed parallel to each other, are laminated to a web of paper with a slight separation gap between the strips so that the strip may be flexed as desired to match the corner profile. The flex bead strips are then applied to the wall corner and secured using wallboard joint compound. Disadvantages of conventional flexible metal corner bead strips include that the metal is relatively heavy, expensive, is easily bent or kinked, and is often difficult to straighten completely when provided in rolled form. In addition, due to the gap between the adjacent strips, it is sometimes difficult to obtain a straight or plumb corner edge, and also the actual corner of the wall is only protected by paper, and as such is prone to impact damage. Conventional flexible plastic corner bead strips suffer from the same susceptibility to impact damage at the wall corner. A corner bead strip is provided for finishing a wallboard corner joint, includes a flexible plastic body having a first flange and a second flange, each flange with a corner edge and an opposite free edge. The corner edges are joined by a central flex zone formed by a plastic composition distinct from a plastic composition used for forming the flanges. A web of paper covers a surface of the body. The web of paper covers the outside surface of the corner bead strip, the opposite inside surface of said body being free of any paper covering. A corner bead strip for finishing a wallboard corner joint is provided, comprising: a flexible plastic body including a first flange and a second flange, each said flange having a corner edge and an opposite free edge, said corner edges being directly joined by a central flex zone encompassing a longitudinal axis of said strip, said flex zone being coextruded and formed by a second plastic composition in a region distinct from and more flexible than a first plastic composition in a distinct region used for forming said flanges said flex zone is made of said second plastic composition which is said first plastic composition combined with a flexibility modifier that is distinct from said first plastic composition, said first plastic composition directly contacting said wallboard corner joint, said first region provided with a “V”-shaped recess between said corner edges, said second region tapering toward each of said free edges, said flexible body being configured for being bendable about said axis to a 90-degree angle, and retaining said bent angle without relaxing back to an initial flat position; said first and second plastic compositions are taken from the group consisting of polystyrene, PVC, PET, and polycarbonate, and at least one of said compositions including said flexibility modifier; and a web of paper covering an outside surface of said body, the opposite inside surface of said body being free of said covering.