Impact resistant plastic corner bead

1. A corner bead for finishing a wallboard corner joint, comprising:

a plastic body having a length, and including a first flange and a second flange each extending generally transverse to said length, each said flange having a rib edge and an opposite free edge, said respective rib edges being joined to form a corner rib and defining an angle;

a web of face paper at least partially covering said body;

said corner rib extends beyond a corner defined by an intersection of planes defined by said first and second flanges, has an interior and defines a hollow interior space;

said plastic construction of said corner bead being reversibly deformable and configured for absorbing an impact, and for facilitating a maintenance of adhesion of said first and second flanges to the wallboard in response to the impact;

at least one of said flanges tapers in thickness from said rib edge to said free edge; and

said corner bead is provided with a bow camber along said length such that said body has a progressive transverse bias that is greatest at a center of said length.

2. The corner bead of claim 1 wherein said plastic is taken from the group consisting of polystyrene, PVC, PET, and polycarbonate.

3. The corner bead of claim 1 wherein said flanges have a thickness in the range of 0.40-0.55 inch near said corner rib and a thickness in the range of 0.025-0.035 inch near said free edge.

4. The corner bead of claim 1 wherein said flanges are mirror images of each other, having corresponding tapering cross-sectional profiles.

5. The corner bead of claim 1 wherein said face paper has a free end extending past said free edge of each of said flanges.

6. The corner bead of claim 5 wherein a length ratio of said free edge to said face paper end is approximately 0.5 to 0.9.

7. The corner bead of claim 1 wherein said corner rib projects approximately 0.015-0.035 inch beyond an exterior surface of said flange.

8. The corner bead of claim 1 wherein said defined angle is in the range of 75°-105°.

9. The corner bead of claim 1 , wherein said face paper is coated with a nose coating.

10. A corner bead for finishing a generally right angle wallboard corner joint, comprising:

a plastic body having a length and including a first flange and a second flange, each said flange having a rib edge and an opposite free edge, said respective rib edges being joined to form a corner rib and defining an angle;

a web of face paper at least partially covering said body;

said corner rib extends beyond a corner defined by an intersection of planes defined by said first and second flanges, has an interior and defines a hollow interior space;

said plastic construction of said corner bead being reversibly deformable and configured for absorbing an impact, and for facilitating a maintenance of adhesion of said first and second flanges to the wallboard in response to the impact;

at least one of said flanges tapers in thickness from said rib edge to said free edge;

wherein said corner rib defines a radius in cross-section in the range of 0.03-0.10 inch for forming a generally right angle corner joint; and

said corner bead is provided with a bow camber along said length such that said body has a progressive transverse bias that is greatest at a center of said length.

11. A corner bead for finishing a wallboard corner joint, comprising:

a plastic body having a length and including a first flange and a second flange each extending generally transverse to said length, each said flange having a rib edge and an opposite free edge, said respective rib edges being joined to form a corner rib defining an angle;

at least one of said flanges tapers in thickness from said rib edge to said free edge;

said corner rib extends beyond a corner defined by an intersection of planes defined by said first and second flanges, said corner rib extending beyond an exterior surface of said flanges, and has an interior and defines a hollow interior space, said corner rib being configured for absorbing shock impacts to the corner joint; and

a web of face paper at least partially covering said body,

wherein said corner bead is provided with a bow camber along said length such that said body has a progressive transverse bias that is greatest at a center of said length, said bias acting in a direction of extension of said flanges from said corner rib.

12. The corner bead of claim 11 , wherein said face paper is perforated.

13. The corner bead of claim 11 , wherein said face paper is coated with a nose coating.