BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] This invention is directed to a ceiling tile for suspended ceiling installations, and more particularly to a novel rigid ceiling tile that inhibits or prevents noxious gases from being emitted by the tile.

[0002] It is known to make ceiling tiles with a rigid core that is usually formed of gypsum or a composition of gypsum. Some gypsum formulations or gypsum compositions may emit sulfur or hydrogen sulfide, which has a noxious odor, and can have a corrosive effect on various materials such as metal, as well as lead to air quality problems and resulting health issues.

[0003] The present invention solves the problem of noxious gas emission from a rigid ceiling tile by providing the ceiling tile with a novel leak tight seal.

DESCRIPTION OF THE DRAWINGS

[0004] In the accompanying drawings,

[0005] Figure 1 A is a simplified schematic perspective view of the ceiling tile incorporating once embodiment of the invention;

[0006] Figure IB is a simplified schematic perspective view of a ceiling tile laminate thereof and a tape that is used to seal the edges of the tile laminate;

[0007] Figure 2 is a sectional view taken on the line 2-2 of Figure 1A;

[0008] Figure 3 is a fragmentary perspective view of a comer of the ceiling tile laminate at an initial taping stage;

[0009] Figure 3 A is a fragmentary perspective view of the corner of the ceiling tile laminate of Figure 3 at a further taping stage;

[0010] Figure 4 is a fragmentary perspective view of another corner of the ceiling tile laminate at a still further taping stage; [0011] Figure 5 is a fragmentary perspective view of the corner of the ceiling tile of Figures 3 and 3 A after the edge taping is completed; and,

[0012] Figure 6 is a simplified schematic view of the ceiling tile laminate in a mandrel during taping of the edges of the laminate.

[0013] Corresponding reference numbers indicate

corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

[0014] Referring to the drawings, a ceiling tile incorporating one embodiment of the invention is generally indicated by the reference number 10 in Figure 1A.

[0015] The ceiling tile 10 has a polygonal shape, such as rectangular. The ceiling tile 10 is preferably in the form of a square, but can also be an elongated rectangle, although other geometric shapes are also feasible.

[0016] The ceiling tile 10 includes a rigid core 12 (Figure 2) that is preferably formed of gypsum. An upper surface 18 (Figure 2) of the core 12 is covered with a sheet 20 of a reflective metallic material, preferably aluminum foil. The reflective sheet 20 is laminated to the upper surface 18 of the core 12 using heat, pressure and adhesive in any suitable known manner.

[0017] A lower surface 26 (Figure 2) of the core 12 is covered with a plastic film 28, preferably formed of a flexible vinyl material such as polyvinyl chloride (PVC) film. The plastic film 28 has an exposed surface 30 that is provided with a design or other known decorative embellishment such as color, with or without embossment.

[0018] A tile laminate 42 (Figure IB) of the gypsum core 12, the reflective sheet 20 and the plastic layer 28 has four peripheral side edges 34, 36, 38 and 40.

[0019] The gypsum core 12 is formed of calcium sulfate which usually originates in gypsum mines that may contain small amounts of sulfur and / or hydrogen sulfide gas. In some instances the gypsum in a gypsum mine contains absorbed sulfur and / or hydrogen sulfide gas (also referred to sulfurous or noxious gases).

[0020] When the mined gypsum is processed in a known manner for use as a component in a ceiling tile most of the absorbed noxious gases are expelled from the gypsum. However some residual noxious gases may remain in the gypsum even after it is processed and formed into a core for a ceiling tile. Thus ceiling tiles with gypsum cores occasionally emit noxious gases, such as emission, even in minuscule amounts, can be sensed in an occupied space below the ceiling tile.

[0021] Applicant has found that the emission of noxious gases from gypsum can be minimized by mining the gypsum from mines that are substantially free of noxious gases. Known sulfur and hydrogen sulfide detectors can be used in a mining operation to detect the presence and concentration of these gases. Thus, it is desirable that gypsum be mined only in environments that are found to be substantially free of sulfur and hydrogen sulfide gases. Nevertheless trace amounts of noxious gases may be present in gypsum that is extracted from a mine that is supposedly free of noxious gases.

[0022] Nevertheless, a ceiling tile having a gypsum core that is believed to be free of noxious gas may still emit miniscule amounts of noxious gas after installation in a ceiling. Such emission of noxious gas occurs primarily at the edges of the ceiling tile because the reflective sheet 20 and the plastic design layer 28 are substantially leak tight members with regard to emission of noxious gas from the gypsum core 12.

[0023] To deal with the noxious gas leakage problem from a ceiling tile applicant provides an adhesive tape 50 (Figures 1 - 6), preferably formed of leak tight vinyl, to cover the side edges 34, 36, 38 and 40 (Figure IB) of the tile laminate 42. The adhesive tape 50 is preferably in the form of a one piece vinyl strip having opposite ends 52 and 54 that overlay each other at one corner of the tile (Figures lA and 5) when applied to the edges 34, 36, 38 and 40 of the tile laminate 42. The tape 50 functions to seal in and prevent the leakage of any noxious gas from the tile 10. [0024] Referring to Figure 1A, at an initial stage of tile taping, the end 52 of the tape 50 is located near a corner 58 (Figures IB and 3) of the tile laminate 42 where the side edges 34 and 36 intersect. The tape ends 52 and 54 are provided with an indentation or notch 60 (Figures IB, 3 and 5) that gives the tape ends 52 and 54, via the notch 60, a lengthy perimeter as compared to a straight cross-cut. The increased perimeter of the tape ends 52 and 54, via the notch 60, enhance the adhesion of the ends 52 and 54 where they are secured and also reduce the visibility of the ends 52 and 54.

[0025] The tape 50 is then applied to the side edges 36, 38 and

40 (Figure IB) with the opposite tape end 54 overlaying the tape end 52 as shown in Figures 1 A and 5.

[0026] The tape 50 can be applied to the edges 34, 36, 38 and

40 by holding the tile laminate 42 in a mandrel 44 (Figure 6). The mandrel 44 is rotatable in a known manner to rotate the tile laminate 42 as the tape 50 is applied to the edges 34, 36, 38 and 40.

[0027] Referring to Figures IB and 2 - 4, the tape 50 has edge portions 46 and 48 that are preferably sequentially folded down on the reflective sheet 20 and the plastic layer 28 at the side edges 34, 36, 38 and 40 of the tile laminate 42.

[0028] For example, the edge portions 46 and 48 of the tape 50 can be folded down in counterclockwise sequence on marginal portions of the reflective sheet 20 and the plastic layer 28 at the side edges 40, 38, 36. As shown in Figure 3A, corner portions 66, 68, 70 and 72 (Figure 1 A) of the tape 50 are folded in and overlap at the corner intersections of the side edges 34 and 36, 36 and 38, 38 and 40, and 40 and 34 of the tile laminate 42. If desired, slight heat and pressure can be applied to the tape 50 where the tape contacts the reflective sheet 20 and the plastic layer 28.

[0029] The taped side edges of the ceiling tile 10 are referred to by the reference numbers 34a, 36a, 38a and 40a (Figure 1 A) that correspond to the side edges 34, 36, 38 and 40 (Figure IB) of the tile laminate 42.

[0030] As shown in Figure 1A the tape 50 at the side edges 34a,

36a, 38a and 40a of the ceiling tile 10 adhere to marginal peripheral portions of the reflective sheet 20 and the design layer 28. The adhesive bond between the tape 50 and the reflective sheet 20 and the plastic layer 28 is substantially leak tight. Therefore the tape 50 provides a leak tight envelope around the peripheral edges 34, 36, 38 and 40 (Figure IB) of the gypsum core 12 of the tile laminate 42.

[0031] Under this arrangement the tape 50 inhibits or prevents any perceptible leakage or emission of noxious gases from the gypsum core 12 beyond the tape 50.

[0032] The ceiling tile 10 is thus provided with sealed leak tight edges that prevent emission of noxious gas from the gypsum core 12 of the ceiling tile 10.

[0033] When the ceiling tile 10 is installed as a hung ceiling, the tile 10 is usually held in a known suspended ceiling tile support frame (not shown). The ceiling tile support frame supports the marginal portions of the tile 10 such that only the design layer 28 i s visible from the space below the hung ceiling tiles. In general, known ceiling tile support frames support the marginal edges of the ceiling tiles and permit drop-in installation of the ceiling tiles. The known ceiling tile support frames thus cover a marginal peripheral portion of the ceiling tile.

[0034] The width of applicant's tape 50 is sized to ensure that the edge portion 46 of the tape 50 that is folded over onto the marginal portions of the design layer 28 is covered by the ceiling tile support frame. Thus there is no visual appearance of the leak tight tape 50 on the ceiling tile 10 in the space below a hung ceiling containing a plurality of the ceiling tiles 10.

[0035] The outside dimensions of the ceiling tile 10 are a matter of choice. For example, the ceiling tile 10 can be two feet by two feet for a square tile and two feet by four feet for a rectangular tile, although other dimensions are feasible.

[0036] The gypsum core 12 can be approximately 5 to 9 mm thick, although other thicknesses are also feasible depending upon the overall size of the ceiling tile. The reflective metallic sheet 20 can be approximately 0.05 to 0.08 mm thick. The material used for the metallic sheet 20 is preferably a known aluminum sheet. The plastic design layer 28 can be approximately 0.05 to 0.07 mm thick, and is made of any suitable known plastic material conventionally used in ceiling tiles.

[0037] As various changes can be made in the above constructions and methods without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.