HK1208650B - Method for making carpet having an underside - Google Patents

Description

Method for making a carpet having an underside

This application is a divisional application of patent application case filed on 2011, 4, 29, with application number "200980143243.8" and entitled "Low weight carpet and carpet tiles and methods of manufacture, sizing and installation".

Cross Reference to Related Applications

This application claims priority from U.S. provisional patent application 61/093,640 filed on 9/2/2008 and U.S. provisional patent application 61/163,907 filed on 3/27/2009, which are incorporated herein by reference.

Technical Field

The present application relates to an improved carpet, and in particular, to a lightweight, dimensionally stable carpet tile (tile), and shape and installation method for such flooring materials suitable for use in mass transit vehicles, particularly including aircraft and other fields.

Background

Public transportation vehicles, such as passenger airplanes, ships, trains, subway cars, and buses, often include carpeting in the passenger compartment of the vehicle. Such carpets are exposed to very harsh environments-high traffic, dirt, heavy equipment (e.g., beverage carts), spills, and the like. In passenger aircraft, the carpet is also subjected to cyclic forces due to repeated changes in cabin air pressure causing the cabin itself and its floor or deck structure to stretch and widen during the expansion cycle and to contract during the compression cycle. These environmental and other conditions result in worn, dirty or damaged carpets that must be replaced frequently.

For the reasons mentioned above, carpets in public transportation vehicles should be designed to be as wear resistant as possible and easy to install and remove. In addition, in the passenger aircraft and marine fields, carpets need to meet industry specifications for fire, smoke, and toxicity. Moreover, in the aircraft field, due to the relationship between aircraft weight and fuel efficiency (and thus operating costs), it is preferable to minimize carpet weight while maintaining the other functional characteristics described above as well as aesthetic needs and objectives.

In the field of public transportation, wide carpets are generally used. The carpet is typically cut into appropriately sized strips, the edges of which are bound ("lockstitched") to prevent or minimize unraveling, which are placed on the surface of the vehicle floor or deck, further cut as necessary, and adhered with adhesive to the vehicle floor or deck. In these areas, broad width carpets exhibit good strength and abrasion resistance, but since the floor is covered with custom cut carpet strips sized to fit the vehicle, removal and replacement of the damaged carpet portion is difficult and unnecessarily expensive because damage to only a portion of the carpet strip necessitates removal and replacement of the entire carpet strip. Also, in the aircraft field, installation and replacement of broadloom carpet requires that the carpet be sized within the aircraft and removed for cutting, as field cutting may damage the surface of the aircraft.

In addition, to remove and replace the carpet strip, the seat and/or other equipment in the vehicle must be removed. For example, in the passenger compartment of an aircraft, replacing a carpet strip may require the removal of several aircraft seats. Another drawback is that it may also be necessary to remove or disconnect the electronics installed in the seat, such as audio connections and video screens.

Carpet tiles may be an attractive option for the public transportation field. Installation is simplified by using carpet tiles that do not require a lockstitch as compared to broad width carpets. Carpet tiles may also allow for more efficient replacement of damaged carpet portions because individual tiles can be replaced rather than the entire broadloom carpet. Another advantage of using carpet tiles in the aircraft field is that if the tiles need to be cut, they can be cut on a cutting board on the aircraft (unlike broad width carpets).

Carpet tiles are typically manufactured and sold in square shapes. When a non-square tile is desired, the square tile is cut to the desired size. This is suitable for most commercial applications, but is inefficient in the mass transit field. The floor of a passenger aircraft has rails that project from the floor and extend most or all of the length of the passenger cabin to allow installation of passenger seats of various sizes with various front and rear seat separations and in various aircraft seating configurations. Since these rails must remain accessible for attaching the seat, they cannot be covered by carpet. Although it is possible to select the seating configuration to utilize rails at equal moment lengths across the aircraft body or breadth, in almost all cases, the seating configuration will require several different widths of carpet in order to cover the entire breadth of the aircraft. When wide width carpet strips are utilized, the strips are cut to match the width between the tracks, and the cut edges are typically tied together. However, with conventional square carpet tiles, multiple tile sizes are necessary for positioning in different gap widths between the rails without cutting the tiles in order to cover the entire width of the passenger compartment: for example, if an aircraft requires four different broad carpet strip widths, four different sizes of square carpet tiles may be required. Alternatively, by cutting it to the desired width, larger tiles can be used, but this is time consuming and wasteful.

In addition, in any carpet field, good dimensional stability is required for carpet tiles. Tiles should resist deformation and maintain their dimensions when subjected to varying temperatures, humidity, pressure or other stresses. Among other things, carpet tiles lacking dimensional stability are more prone to buckling, or "doming" in the center of the tile, and are less prone to flattening. Good dimensional stability is even more important in the public transportation field where the tiles are subjected to harsh environmental conditions as described above. Carpet tiles for use in passenger aircraft will also need to meet applicable regulations for fire, smoke and toxicity.

Current carpet tile technology can produce carpet tiles with good dimensional stability and fire and smoke characteristics. One such carpet tile is described in reissue U.S. patent No. Re. 34,951, which is incorporated herein by reference. Other prior art carpet tiles are described in U.S. patents 4,010,301, 4,010,302, 5,198,277, 5,204,155 and 5,560,972, the disclosures of which are incorporated herein by reference.

Each of these patents discloses carpet tiles that include carpet pile embedded, tufted into, or otherwise attached to a primary backing layer. These carpet tiles also include additional backing layers formed of various materials and that provide dimensional stability and strength to the carpet tile. Common backing layer materials include polyester, polyvinyl chloride, and non-woven fiberglass, among others. To reduce the cost of the backing, one or more fillers, such as calcium carbonate, are typically incorporated into the backing layer. These and most other conventional carpet tiles are relatively heavy, which is not an undesirable property because weight contributes to the ability of such tiles to flatten and remain in place when installed.

While such conventional carpet tiles are suitable for many commercial and residential applications, because of their relative weight, they are not well suited for applications requiring lightweight tiles, which makes them less suitable for use in certain mass transit vehicles, including passenger aircraft in particular. Also, the wide-format carpets being used in public transportation vehicles, while potentially lighter than conventional carpet tiles, have disparate dimensional stability that prevents wide-format carpets from being cut into tiles and installed in the vehicle.

Accordingly, there is a need for a method of installing carpet tiles in a space, such as in a public transportation vehicle, that minimizes the number of different carpet tile products that need to cover the width of the space and that does not require cutting of the tiles. There is also a need for a method of installing a carpet in a mass transit vehicle that does not require the removal of equipment such as passenger seats from the vehicle. There is also a need for a lightweight, durable carpet tile for public transportation, particularly passenger aircraft, that meets applicable smoke, fire and other requirements.

Disclosure of Invention

The present invention provides low weight carpet and carpet tiles suitable for use in mass transit vehicles, particularly passenger aircraft and other applications where product weight, construction, installation and considerations as described below are appropriate. The carpet and carpet tiles of the present invention may have a carpet pile and at least one backing layer. The backing layer may employ low weight fillers such as glass spheres, preferably hollow glass microspheres. In another embodiment, the carpet and carpet tile meet transportation industry standards for fire, smoke, and toxicity. Tiles can be sized during manufacture and installed in a configuration that minimizes the number of tile sizes required for installation and the need to cut tiles. The pattern for such tiles may be orthogonally ambiguous or may be adapted for "random" installation, facilitating tile installation that may be oriented at a different orientation than during manufacture. In another embodiment, the passenger aircraft cabin flooring and installation methods described herein facilitate the initiation and replacement of installation of an aircraft or other vehicle or other location without removing seats or other obstructions. Such installation may include, for example, a floor having rectangular carpet tiles installed thereon, and the carpet may be installed, removed, and replaced within the aircraft without removing the seat from the aircraft.

Drawings

FIG. 1 is a diagram of a carpet tile configuration according to one embodiment of the present invention.

FIG. 2 is a diagram of a carpet tile configuration according to another embodiment of the present invention.

Fig. 3 is a schematic side view of one embodiment of a carpet of the present invention having at least one secondary backing layer.

Fig. 4 is a schematic side view of a second embodiment of the carpet of the present invention having at least two secondary backing layers.

Fig. 5 is a schematic side view of a third embodiment of the carpet of the present invention with an additional optional backing layer.

FIG. 6 is a schematic side view of a carpet backing line used to produce a carpet in one embodiment of making a carpet tile of the present invention.

Fig. 6a is a schematic side view of a portion of the backing wire of fig. 6.

Detailed Description

One embodiment of the present invention is a method of installing a carpet in a mass transit vehicle, particularly a passenger aircraft. Although the method is described as applied to a passenger aircraft passenger compartment as an example, the method may be applied to other public transportation vehicles such as trains, buses, subway cars, and ships.

According to the method, the passenger compartment is carpeted with a minimum number of different size carpet tiles. As noted above, due to the different possible seating configurations in any given aircraft, aircraft passenger compartments typically require many different sizes of carpet to cover the entire breadth of the aircraft. One exemplary configuration is provided in fig. 1. In the illustrated configuration, the passenger compartment of the aircraft 100 has a width W and a length L. The seating configuration used in an aircraft necessitates carpet laying in 6 areas 110, 120, 130, 140, 150 and 160 having widths A, B, C, D, B and A, respectively. Note that regions 110 and 160 have the same width a and regions 120 and 150 have the same width B.

In one embodiment of the invention, the size of the orthogonal fuzzy or randomly installed rectangular carpet tiles minimizes the number of different carpet tile products required to lay the passenger cabin. The first rectangular carpet tile product has a base equal to one of the desired widths (e.g., width a) and a height equal to the other of the desired widths (e.g., width B). In this manner, a first rectangular carpet tile product can be used to tile areas 110, 120, 150, and 160 by covering the width of areas 110 and 160 with the bottom A of the first tile and covering the width of areas 120 and 150 with the high B of the first tile.

The second rectangular carpet tile product has a base equal to the other of the desired widths (e.g., width C) and a height equal to the last of the desired widths (e.g., width D). Thus, by taking the width of region 130 for the bottom C of the second tile and the width of region 140 for the high D of the second tile, the second tile can be used to tile regions 130 and 140.

The aircraft passenger compartment can therefore be paved with only two different sizes of carpet tile products. If a conventional square carpet tile product is used, four different sizes of square products may be required, the four products having sides of lengths A, B, C and D. By employing the above-described laying method, the number of different carpet tile products can be reduced by half (e.g., from 4 to 2). Moreover, by employing the above-described method, side-to-side cutting of tiles (i.e., cutting of tiles to adjust their width to fit within a particular area) may be substantially avoided, but it will be recognized that some cutting may be required, for example, at the front and/or rear of the passenger compartment, as the passenger compartment narrows there.

As known to those skilled in the art, the use of carpet tile patterns as described in U.S. Pat. Nos. 6908656 and 7083841, which are incorporated herein by reference, facilitates the aesthetic installation of rectangular carpet tiles of the present invention that are acceptable in installations where the fibers are "facing" in a different direction than they are "facing" during the tile production process. It should be recognized, however, that such patterns on carpet fabric that can be cut into square carpet tiles that are orthogonally obscured are not necessarily cut into rectangular tiles of any size that are all orthogonally obscured. This is because, for at least some patterns, when selecting the cutting location, the tile must be sized and cut with sufficient reference to the pattern on the fabric to avoid generating a particular tile shape that appears to be unsuitable. Such shapes sometimes occur when the tile edge is too close to the edge of the shape on the tile, making the shape very different from other shapes on the tile, and thus odd or inappropriate.

In an exemplary embodiment of the method of the present invention, the aircraft seat configuration is such that the carpet must be laid in 5 zones: 210. 220, 230, 240 and 250, as shown in fig. 2. Regions 210 and 250 have the same width E and regions 220 and 240 have the same width F. Region 230 has a width G.

In this embodiment, the first rectangular carpet tile product has a base equal to one of the desired widths (e.g., width E) and a height equal to the other of the desired widths (e.g., width F). In this manner, a first rectangular carpet tile product can be used to tile the areas 210, 220, 240, and 250 by covering the width of the areas 210 and 250 with the bottom E of the first tile and covering the width of the areas 220 and 240 with the high F of the first tile.

A second rectangular carpet tile product having a base equal to another desired width (e.g., width G) may be used to tile an area 230. Since there are no other areas in this configuration where carpet is to be carpeted, the height H of the second rectangular carpet tile is not important and any desired height can be selected. Alternatively, the height H may be selected to be equal to one of the desired widths E or F.

Thus, in this embodiment, two different sizes of carpet tile products may be laid in the aircraft passenger compartment. If a conventional square carpet tile product is used, three different sizes of square products may be required, the three products having edges of lengths E, F and G. Since in this configuration the number of required zone widths is an odd number, the number of different carpet tile products cannot be halved, but can be determined by the following equation:

(n-1)/2+1；

where n is equal to the number of different carpet area widths spanning the width of the passenger compartment. The value of n in the embodiment shown in fig. 2 is 3, which means that the multiple carpet areas have three widths (5 areas need to be covered, whereas two of the areas have the same width, leaving three different widths E, F and G). Thus, the number of different carpet tiles required in this example is (3-1)/2+1, i.e., 2. In an example configuration with 5 zones of different widths, the number of different carpet tile products may be reduced to (5-1)/2+1, i.e., 3.

It will be appreciated that if a particular aircraft configuration requires that the carpet be laid in an even number of areas of different widths (such as the embodiment described above in FIG. 1), the number of different carpet tile products required may be represented by the following equation:

，

wherein n is as defined above.

The carpet tile may be installed in a vehicle using conventional adhesives. Such adhesives include, but are not limited to, latex, hot melt adhesives, and water-based adhesives. Exemplary adhesives include asphalt-based hot melt adhesives, polyurethane adhesives, polyethylene adhesives, thermoplastic polyolefin adhesives, pressure sensitive acrylic adhesives, and combinations thereof. Preferably, the adhesive is selected so that it leaves little or no residue on the aircraft floor when the tile is removed, but the adhesive need not be so limited. A preferred Adhesive is an "APAC" acrylic Adhesive available from All pure plasma Adhesive Company of Dalton, Georgia. Other adhesives for applying carpet tiles to floors are also known.

The adhesive may be applied directly to the floor or tile when it is to be carpeted, or it may be pre-applied to the carpet tile during construction as a releasable adhesive layer that may be covered by peel strips, film or sheet (e.g., paper, plastic), or the like. One removable adhesive is AquaBlock pressure sensitive adhesive sold by Rohm and Haas. Carpet tiles of the present invention may also be installed using, for example, double-sided tape available from Adchem Corporation of Riverhead, new york.

Alternatively, the carpet tiles may be mounted on the aircraft floor using adhesive connectors or squares, such as those developed by Interface, Inc. The bonded connector developed by Interface, Inc is an approximately 3 "polyethylene film connector formed from a composite acrylic adhesive applied to a polyethylene terephthalate (PET) backing with a PET polyester release liner. The connectors are designed to bond the corners or edges of the carpet tiles together. However, this connector only adheres carpet tiles to each other and not to the floor (i.e., the adhesive is on only one side of the connector), thereby creating a "floating floor". Once installed, the connector provides a good horizontal bond to prevent the tiles from pulling apart from each other. But the carpet tile is easily detached from the connector by pulling the tile vertically. The use of the connector thus greatly simplifies installation and removal of carpet tiles.

If it is deemed undesirable to install "floating floor" carpet tiles without any attachment to a vehicle, such as in an aircraft or other alternative vehicle, the following attachment means may be selected: with double-sided tape, adhesive is applied directly to the vehicle floor and/or a portion of the carpet tile, or by adhesively attaching at least some of the connectors to the floor. In another alternative installation, the tiles may be "free-standing" with no attachment means to the underlying floor or to each other.

The carpet according to the above method is employed so as to allow the carpet to be laid for the floor of a public vehicle without removing seats and/or other equipment from the vehicle.

Example 1

Installation of the carpet in the cabin of an aircraft of the boeing 737-700 series requires that the carpet be laid in 6 zones 110, 120, 130, 140, 150 and 160 as shown in fig. 1 (not to scale for this example). The seat rails are located longitudinally within the cabin between regions 110 and 120, 120 and 130, 140 and 150, and 150 and 160. The emergency lighting track is located longitudinally within the nacelle between the areas 130 and 140.

The configuration of this example requires the following widths:

region(s)	Width (inch)
		110	18
120	19.25
		130	32
140	14
		150	19.25
160	18

Note that these regions have four different width requirements (18, 19.25, 32, and 14 inches) and that regions 110 and 160 have the same width and regions 120 and 150 have the same width.

Carpet tiles installed in the nacelle can be sized to use only two different tile sizes, one tile size being 18 "in length and 19.25" in width, and the other tile size being 32 "in length and 14" in width. An 18 x 19.25 tile may be installed in regions 110, 120, 150, and 160, and a 32 x 14 tile may be installed in regions 130 and 140.

Example 2

The test installation was completed in a simulated deck configuration of the boeing 737-ion 700 series aircraft. The initial configuration was consistent with that described in example 1 above. However, when considering this installation, it is appreciated that region 130 of width 32 "may be filled by tiles of widths 14" and 18 "(14 +18= 32). Thus, tiles of the following widths are required:

region(s)	Width (inch)
		110	18
120	19.25
		130	14 and 18
140	14
		150	19.25
160	18

There are then only three different width requirements: 18 "(regions 110, 160 and a portion of region 130); 19.25 "(regions 120 and 150); and 14 "(region 140 and a portion of region 130). Two different sizes of tiles are still required (according to the above formula ((3-1)/2) +1= 2), however, it is recognized that the following tile sizes may be employed: 18'' × 19.25'' and 14'' × 19.25 ''. By sizing tiles in this manner, the same tile length (19.25 ") is used for each tile, significantly simplifying cutting of tiles from a custom fabric and minimizing cutting waste, since a die having the same 19.25" length can be used.

Example 3

Installation of the carpet in the cabin of a boeing 777 economy class aircraft requires that the carpet be laid in 9 zones having the following widths:

region(s)	Width (inch)
		1	7
2	32.5
		3	39.5
4	20.5
		5	20.5
6	20.5
		7	39.5
8	32.5
		9	7

These 9 zones have four different width requirements (7, 32.5, 39.5 and 20.5 inches), the following zones have the same width: 1 and 9 (7 inches); 2 and 8 (32.5 inches); 3 and 7 (39.5 inches) and 4-6 (20.5 inches).

Carpet tiles installed in the nacelle may be sized to use only two different tile sizes, one tile size being 7 "in length and 32.5" in width, and the other tile size being 39.5 "in length and 20.5" in width. A7 × 32.5 tile may be installed in zones 1, 2, 8, and 9, and a 39.5 × 20.5 tile may be installed in zones 3-7.

Example 4

The configuration of example 3 can be modified as follows by dividing the areas 3 and 7 into two additional areas of width 7 "and 32.5":

region(s)	Width (inch)
		1	7
2	32.5
		3	7 and 32.5
4	20.5
		5	20.5
6	20.5
		7	7 and 32.5
8	32.5
		9	7

These 9 zones now have only three different width requirements (7, 32.5 and 20.5 inches), and the following zones have the same width: 1. 9 and a portion (7 inches) of regions 3 and 7; 2. 8 and a portion (32.5 inches) of zones 3 and 7; and 4-6 (20.5 inches).

Carpet tiles installed in the nacelle may be sized to use only two different tile sizes, one tile size being 7 "in width and 20.5" in length, and the other tile size being 32.5 "in width and 20.5" in length. A7 × 20.5 tile may be installed in regions 1, 4-6, 9 and a portion of regions 3 and 7, and a 32.5 × 20.5 tile may be installed in regions 2, 4-6, 8 and a portion of regions 3 and 7.

As with the configuration described in example 2, cutting of the tiles is simplified by using the same length (20.5 ") for each tile.

Carpet tile weight

Another embodiment of the present invention is a low weight carpet tile suitable for use in the public transportation field. The carpet tile includes carpet pile tufted or otherwise embedded within or attached to a primary backing layer, optionally with at least one additional backing layer, or optionally multiple backing layers, as shown in fig. 3, with a carpet 310 having face yarns 312 tufted into a tufted primary layer 314 and a precoat layer 316. Such a structure having yarns tufted into a tufted primary layer and optionally a pre-coat is sometimes referred to as a "face towel".

Fig. 4 shows another alternative embodiment, a carpet tile 410 having an additional secondary backing layer 418, and yarns 412 tufted into a tufted primary layer 414 and a pre-coat layer 416. The tufted primary layer 414 and the pre-coat layer 416 may be formed of the same materials as the tufted primary layer 314 and the pre-coat layer 316 described above.

Additional backing layers and components may also be employed, as well as other carpet constructions other than tufts. For example, the face yarn structure may be woven or sintered, or other alternatives.

In one embodiment, the face fibers are formed from nylon yarn, specifically nylon 6.6 or nylon 6 yarn. However, other yarns may also be used to form carpet pile including, but not limited to, wool/nylon blends, fibers from polyester, polypropylene, Polyetherimide (PEI) and polylactic acid (PLA), as well as other types of fibers known for use in the carpet art.

One suitable material for the tufted primary layers 314, 414 of the low weight carpet tile is a non-woven polyester. Other tufted primary layer materials are also known and available so long as they contribute (or at least do not unduly detract) from stability, durability, low weight, and other desirable properties described herein.

The precoat layers 316, 416 are formed from a polymeric material such as polyvinyl chloride, Styrene Butadiene Rubber (SBR), styrenated acrylic copolymer, acrylic, Ethylene Vinyl Acetate (EVA), polyethylene, ethylene propylene diene methylene terpolymer (EPDM) rubber, urethane, nitrile rubber, neoprene, and chloroprene rubber. It may also be formed from a bituminous coating material. The precoat layers 316, 416 may be styrenated acrylic copolymers available from Broadview Technologies of Newark, nj that have good flame retardancy and are well compatible with the tufted primary and secondary backing layers.

The secondary backing layer 418 preferably comprises a reinforcing layer of mesh or mat that incorporates a polymeric material such as polyvinyl chloride, polypropylene or polyethylene terephthalate (PET) therein. The reinforcing layer is preferably formed of a flame retardant material such as fiberglass, ceramic or polyvinyl chloride fibers, and may have a woven or non-woven structure. A particularly preferred secondary backing layer comprises polyvinyl chloride incorporated into a non-woven glass fibre mat. One useful polyethylene resin is the PVC acrylic copolymer Geon-138 resin available from PolyOne. A wide range of alternative commercial PVC resins may also be used, provided they provide the desired qualities described herein, as well as other suitable properties known to those skilled in the art in the manufacture of carpet tiles.

The secondary backing layer may also include a plasticizer to increase the flexibility of the layer. Useful plasticizers include phosphate esters, diisononyl phthalate (DINP), tricresyl phosphate (TCP), triphenyl phosphate isopropyl (TPP), ricino-based plasticizers and combinations thereof. A combination of TPP and phosphate esters is a preferred plasticizer. TPP is available from Great Lakes Chemical Corp. and phosphate is available from PAG Holdings. Other plasticizers are also known and may be used as appropriate.

It is also desirable to incorporate an optional smoke suppressant in the secondary backing layer. A useful smoke suppressant is Molybdenum trichloride available from Climax Molybdenum co.

The carpet pile of the present invention is preferably lighter in weight than conventional carpet piles. Weight reduction can be achieved by using a low weight face structure. Suitable face fibers are nylon, wool, blends of nylon and wool, and other known carpet fibers.

In addition, the tuft primary layers 314, 414 and additional layers (e.g., 316, 416, and 418) are preferably lighter in weight than comparable layers found in most conventional carpet tiles. Weight reduction in these layers can be achieved by using low weight fillers instead of the known filler materials. As discussed above, the use of low weight filler materials for carpet tiles has not been previously considered because low weight has not been an important consideration in previous carpet tile constructions.

Glass spheres, particularly hollow glass microspheres, are useful as low weight filler materials. One such microsphere filler material is available from Potters Industries, inc. Other suitable filler materials include fumed silica, Aerogels (silica-based foams available from Aspen Aerogels, inc.), fly ash, calcium carbonate, zinc borate, aluminum trihydrate, magnesium hydroxide, and glass fiber stabilizing fibers. Some of these materials provide the flame retardancy needed in carpet tiles designed for aircraft or other vehicle applications. However, glass microspheres may be preferred due to their low weight and flame retardancy. Microsphere filler materials, such as those available from Potters Industries, inc, of Valley Forge, pennsylvania, are formed from sodium silicate, sodium borate, water, and precipitated silica. But these are expensive. Other less expensive hollow microspheres are available and may also be suitable as filler materials. These hollow microspheres provide the backing layer(s) with a volume comparable to other filler materials (e.g., calcium carbonate), but with a significant weight reduction. For example, calcium carbonate has a density of about 2.7 g/cc, whereas the density of microsphere filler materials obtained from Potters Industries, Inc. of Valley form, Pa., is only about 0.12 g/cc.

In addition to physically adding filler material to the backing layer, the backing layer may be fluffed by mechanical or chemical treatment processes without substantially increasing the weight. For example, voids may be introduced in one or more backing layers by blowing or foaming with air, nitrogen, or some other inert gas. An example of a chemical loft approach suitable for the backing layer is provided by Expancel, which is an expandable microsphere incorporating droplets of liquid isobutane surrounded by a polymer shell. When exposed to heat, the shell softens and the isobutane vaporizes, causing the microspheres to expand.

Weight savings may also be achieved by reducing the weight of the face yarns 312, 412 within the carpet pile. A typical carpet pile is formed from 4 face yarns and is constructed in a loop or cut pile arrangement. By reducing the face yarn to 3 plies, the weight of the carpet pile can be reduced from about 18-20 osy (ounces per square yard) to about 16 osy or less, and more preferably, about 14 osy or less. Alternatively, by tufting the finished yarn ends in a lighter format (e.g., by varying the stitch count per inch, pile height, machine gauge, or some combination of these), a lower weight of 4-ply yarns may be employed. When low areal weight yarns are used, a black (or other dark colored) tufting primary layer may be used to reduce "bottoming", i.e., the tufting primary layer is visible between the yarns. By incorporating conductive materials such as carbon black or conductive glass fibers, the static dissipative properties of the finished carpet fibers can be improved.

As noted above, any carpet tile used in public transportation vehicles, such as passenger aircraft, should preferably meet the specifications for fire, smoke, and toxicity. Thus, the carpet tile preferably meets one or more of the following criteria: federal Aviation Regulation ("FAR") 25.853 (inside cabin), Boeing BSS 7239 (toxic Smoke), Boeing BSS 7238 (optical Smoke Density), Boeing D6-51377 (Smoke toxicity) and Boeing BSS 7230("Determination of airborne Material Flammability"). These standards are incorporated herein in their entirety by reference.

To meet one or more of these criteria, if the tufted primary layer 314, 414 is a spunbond (spun laid) non-woven polyester available from, for example, freudenberg non wovens NA, the backing may be treated with phosphate or antimony to improve its flame retardancy.

The carpet tile may also include an additional layer of flame retardant latex material (not shown), such as is available from Broadview Technologies of Newark, new jersey. If additional flame and fire retardancy is desired, this layer may be included in addition to the flame retardant primary backing layer described above. To reduce the amount required to 10 or less ounces per square yard ("osy"), the precoat may be highly foamed.

The carpet tile may include another optional layer (e.g., a fiberglass layer), as shown in fig. 5, which shows the carpet tile 510 having face yarns 512 tufted into a tufted primary layer 514 and backed by a pre-coat layer 516, a secondary backing layer 518, and a fiberglass layer 520. The fiberglass layer 520 provides additional dimensional stability to the carpet tile, which is useful in aircraft and other public transportation applications. Another optional layer is shown as an adhesive layer 522 pre-applied to the carpet tile during construction.

The fiberglass material used for both the secondary backing layer 418 and the optional additional fiberglass layer 520 is non-woven micro-denier fiberglass available from, for example, Owens Corning Fiberglas Company of Toledo, ohio. Micro-denier glass fibers: generally have good fire and smoke characteristics; the fibers are smaller than conventional fiberglass materials and therefore less skin irritating; the backing layer thus formed is less sensitive to buckling due to pressurisation and depressurisation of the aircraft cabin. Additionally, micro-denier glass fibers are less porous than conventional glass fibers, and therefore produce a more solid surface per unit weight than conventional glass fibers. While micro-denier glass fibers have these properties, other materials, including conventional fiberglass backing materials, may be employed.

As noted above, the low weight carpet tiles described herein preferably provide good dimensional stability characteristics. One method of measuring the dimensional stability of a tile is specified in the international organization for standardization (ISO) 2551, also known as the Acchen test for dimensional stability. The low weight carpet tiles described herein preferably have a dimensional stability of +/-0.2% (tile size variation in either direction of no more than 0.2%), more preferably +/-0.1% (tile size variation in either direction of no more than 0.1%), as determined by ISO 2551.

In some applications of the present invention, static dissipation is required. For example, compliance with ANSI/ESD S20.20, which is an electrostatic discharge association standard for developing electrostatic discharge control programs for protecting electrical and electronic parts, components and equipment. There is also a need for carpet tiles that meet the electrostatic discharge specifications issued by the manufacturer of the vehicle (e.g., aircraft) in which the carpet tile will be installed. To facilitate this, conductive filaments or other components, such as carbon black, metal fibers or conductive glass fibers, may be incorporated within each yarn end to dissipate static electricity. For example, with three yarns, the conductive filament may be twisted or air-entangled with the other three yarns. Alternatively, or in combination, a conductive material such as carbon black may be incorporated into one or more backing layers.

Carpet tiles incorporating the above materials can be made at significantly lower weights than current carpet tiles. Typical carpet tiles range in weight from about 120 to about 130 osy. In contrast, carpet tiles formed from the above materials may weigh less than about 100 osy. While carpet tiles weighing about 82-100 osy are suitable, tiles weighing about 66-82 osy are preferred. More preferred are carpet tiles having a weight of about 56-66 osy. Most preferred are carpet tiles having a weight of about 48-56 osy or even 42-48 osy. For use in the passenger aircraft field, lower weight tiles are preferred.

Example 5

The following formulation was used for the above secondary backing layer:

manufacture of

Low weight (and other) carpet tiles may be manufactured by producing a composite carpet fabric 612 as shown in fig. 6 using a process comprising:

placing the fiberglass fabric 614 on a conveyor belt or other suitable support structure in a carpet manufacturing line;

a resin layer 618 (as shown above in example 5) is applied over the fiberglass fabric 614;

placing a tufted face towel 620 on the resin layer 618;

heating the composite carpet fabric 612 to reduce the viscosity of the resin layer 618 and begin curing it;

pressure is applied by contacting the composite carpet fabric 612 with at least one embossing, nipping or similar pressure applying roller ("pressure roller") that is free of stops or otherwise configured to apply significant pressure, as further described below.

Fig. 6 and 6a are schematic side views of a backing thread 610, which backing thread 610 may be used to make a composite carpet fabric 612 of the present invention by unwinding a fiberglass fabric 614 onto a lower conveyor belt 616. A resin layer 618 is deposited on top of the fiberglass fabric 614 and a tufted or other face towel 620 is placed within the resin layer 618. The fiberglass fabric 614 and resin layer 618 form the secondary backing layer 418 described above. The composite carpet web 612 is heated, for example, by passing it through a heated platen 622. The platen 622 may be heated by hot oil, steam, electricity, or some other heat source. The heated resin within resin layer 618 begins to cure and its viscosity decreases. The composite fabric should preferably be heated to at least about 315 ° f. Just prior to composite carpet web 612 passing between pressure rollers 628 and 630, additional heat is provided by Infrared (IR) heater 626 positioned adjacent to secondary backing layer 418 of composite carpet web 612.

The composite carpet web 612 is typically cooled in ambient air and then deposited onto a drum (not shown). Alternatively, the cooled composite carpet fabric 612 is not rolled up, but rather may immediately proceed to a cutting station (not shown) and be cut into tiles of the desired size.

The thermal profile during the manufacturing process is important. Good results have been obtained by maintaining composite carpet fabric 612 at a relatively constant temperature throughout most of the manufacturing cycle and employing additional heaters 626 just prior to composite carpet fabric 612 passing between pressure rollers 628, 630 to force some of the molten resin into and around the embedded backstitch or tufted portions of the tuft primary layers 314, 414. Such an inverted stitch is formed, for example, in face yarn 312 (fig. 3) in a tufting primary layer (e.g., tufting primary layer 314 in fig. 3). The increased temperature of the backing material at pressure rollers 628, 630 causes a decrease in the viscosity of resin layer 618, which facilitates better penetration of the backing material into the tufted primary layer.

Applying substantial pressure with pressure rollers 628 and 630 facilitates forming a lighter, stronger composite carpet web 612. This may be accomplished with conventional opposing pressure rollers 628 and 630 by omitting stops normally associated with at least one of pressure rollers 628 and 630. The stop is used in most carpet manufacturing applications to limit movement of one or both of the rolls toward each other, thereby maintaining a minimum spacing between the rolls to prevent crushing of the face yarns 312, 412. Removing the stops allows the still hot backing material to be pressed further into and around the back stitches in the tufted primary layers 314, 414, allowing a strong composite carpet fabric 612 to be formed with less backing material. Obviously, because the substantial force applied by the rollers is very short, undesirable crushing of the face yarns 312, 412 is limited.

Hydraulic or other pressure mechanisms may be used for one or both of the pressure rollers if desired.

Roller 628 may be a steel roller or other similar material, and may be a conventional embossing roller or other roller capable of applying pressure on the backing material as described herein. The roller 628 is preferably stationary, i.e., it does not move perpendicular to the face of the composite carpet fabric 612 (but it rotates). The roll may be cooled to facilitate "locking" of the backing material into the tufts of the face towel.

The roll 630 of contacting face yarn does not require, and generally should not, transfer heat to the face yarn it contacts, and may have a roll face of rubber or other similar material. Roll 630 is preferably not stationary, i.e., it is movable perpendicular to the face of composite carpet web 612 (toward and away from roll 628). The roll 630 may also be cooled.

The diameter of rollers 628 and 630 is typically 11-13 ". As mentioned above, the amount of pressure applied to the one or more rollers may be such that undesirable crushing of the face tissue does not occur. In a configuration where a 90 "long, 13" diameter rubber coated roll 628 is driven by a pair of pneumatic pistons of approximately 1.5 "diameter, pressures of up to 75 pounds per square inch are applied to the pistons without causing undesirable face tissue collapse. Other pressures may be used with other piston and roller sizes and to accommodate variations in backing material, face yarns, or otherwise.

The composite carpet web may pass between rollers 628, 630 at a suitable speed which will allow the resin in resin layer 618 to be pressed into the tufts within face towel 620 without crushing face towel 620 and which will allow for sufficient heat transfer and curing of the resin within composite web 612. A line speed of 20 feet per minute has been found to be suitable. Other line speeds may be used as long as they provide sufficient cure time for the resin within the composite web 612.

Benefits derived from such manufacturing techniques include:

1) less backing material is used. The combined heat and pressure presses the resin into the voids of the tufted face towel 620 to provide better tuft lock and delamination resistance.

2) The fiberglass secondary backing layer is driven almost, if not completely, into the composite carpet fabric so that the fiberglass is not exposed. This allows the use of less expensive non-irritating fiberglass products than would be often used if the installer were likely to touch the exposed fiberglass. Moreover, the performance of the tiles is improved since generally the closer the glass fibers to the faces provide better dimensional stability and less wrinkling of the glass fibers.

3) The use of pressure essentially corrects for backing defects that can be transferred to the face and cause uneven wear. The more direct contact between the face tissue and the backing improves the appearance of the product as it becomes worn. The heat and pressure smooth the inverted stitch profile.

4) In conventional carpet tile production, it is difficult to drive the glass fibers into the resin if the resin composition is too viscous. However, this is not very important when made according to the present invention, as the glass fibers are pushed towards the face of the carpet with pressure. This allows the use of more viscous resin compositions and, therefore, less resin than some conventional manufacturing processes.

5) Less resin was used:

approximately half the size or "footprint" of the backing line,

reduces the backing cure time (thereby requiring a shorter tape) and does not require reheating to laminate the towel,

so that the curing is easier to realize,

the production of tiles that are easier to cut,

the weight of the utility model is reduced, and the weight of the utility model is reduced,

making it easier to push the glass fibers in the secondary backing closer towards the "top" or face of the tile (because there is less resin component that must move through the glass fibers), and

less space is required to transport and store tiles so that more tiles can be packed in a particular sized container.

The foregoing is provided for the purpose of illustrating, explaining and explaining embodiments of the present invention. Further modifications and variations to these embodiments will be apparent to those skilled in the art and may be made without departing from the spirit of the invention or the scope of the claims. Moreover, not all aspects of the invention need to be implemented in every embodiment of the invention. For example, some embodiments of the invention may be manufactured or installed in a wide-width configuration, while others may employ square tiles. Other embodiments may not use the lightweight filler described herein or may not use a pressure roll when manufacturing a product.

Claims (20)

1. A method for making a carpet having an underside, comprising:

a. placing the fabric onto a conveyor belt in a carpet manufacturing line;

b. applying a resin layer to the fabric, wherein the resin layer has a viscosity;

c. placing a tufted face towel over the resin layer to form a composite structure,

d. heating the composite structure at least to a temperature at which the viscosity of the resin layer begins to decrease; and

e. applying pressure to the composite structure by passing the composite structure between a first pressure roller and a second pressure roller while maintaining the composite structure at or above a temperature at which the viscosity of the resin layer begins to decrease, wherein the first pressure roller contacts the tufted face tissue and the second pressure roller contacts the fabric and the pressure drives the fabric and the resin layer into the composite structure such that the fabric is not exposed,

wherein at least one of the first pressure roll and the second pressure roll is cooled.

2. The method of claim 1, further comprising allowing the composite structure to cool and cutting the composite structure into carpet tiles.

3. The method of claim 2, wherein the carpet tile meets one or more of the following fire, smoke, or toxicity criteria: FAR 25.853; BSS 7239; BSS 7238; d6-51377 and BSS 7230.

4. The method of claim 1, wherein the fabric comprises fiberglass.

5. The method of claim 4, wherein the glass fibers are micro-denier glass fibers.

6. The method of claim 4, wherein the resin layer comprises polyvinyl chloride, polypropylene, polyethylene terephthalate, or a combination thereof.

7. The method of claim 6, wherein the resin layer further comprises a plasticizer.

8. The method of claim 7, wherein the plasticizer comprises diisononyl phthalate, tricresyl phosphate, triphenyl phosphate isopropyl, a ricino-based plasticizer, or a combination thereof.

9. The method of claim 8, wherein the plasticizer comprises triphenyl phosphate isopropyl.

10. The method of claim 6, wherein the resin layer further comprises a filler selected from the group consisting of glass spheres, fumed silica, silica-based foam, and combinations thereof.

11. The method of claim 10, wherein the filler comprises glass spheres, and wherein the glass spheres are hollow glass microspheres.

12. The method of claim 1, wherein the carpet weighs less than 82 ounces per square yard.

13. The method of claim 1, wherein the carpet weighs less than 56 ounces per square yard.

14. The method of claim 1, wherein the carpet has a dimensional stability of equal to or less than plus or minus 0.2% as defined by ISO 2551.

15. The method of claim 1, wherein the temperature at which the viscosity of the resin layer will begin to decrease is at least 315 ° f.

16. The method of claim 1, wherein the first pressure roller is rubber or rubber-coated and the second pressure roller is steel.

17. The method of claim 1, wherein the pressure is applied by the first and second pressure rollers, and wherein a stop associated with at least one of the first and second pressure rollers is removed.

18. The method of claim 1 wherein the tufted face towel comprises yarns tufted into a tufted primary layer and a pre-coat layer on the underside of the tufted primary layer, wherein the pre-coat layer is flame retardant.

19. The method of claim 1, wherein the resin layer further comprises a smoke suppressant.

20. A method for making a carpet having an underside, comprising:

a. placing a fiberglass fabric onto a conveyor belt in a carpet manufacturing line;

b. applying a resin layer onto the fabric, wherein the resin layer has a viscosity and includes a filler with glass spheres;

c. placing a tufted face towel over the resin layer to form a composite structure, wherein the tufted face towel includes yarns tufted into a tufted primary layer and a pre-coat layer on the underside of the tufted primary layer, wherein the pre-coat layer is flame retardant;

d. heating the composite structure at least to a temperature at which the viscosity of the resin layer begins to decrease; and

e. applying pressure to the composite structure by conveying the composite structure between a first pressure roll and a second pressure roll while maintaining the composite structure at or above a temperature at which viscosity of the resin layer begins to decrease, wherein: 1) the first pressure roll contacting the tufted face tissue and the second pressure roll contacting the web, 2) at least one of the first and second pressure rolls being cooled; and 3) the pressure drives the fiberglass fabric and the resin layer into the composite structure such that the fabric is not exposed,

wherein the carpet weighs less than 82 ounces per square yard.