Description:FIELD OF THE INVENTION
The present disclosure relates to a carpet-tile comprising a tactile surface for commercial, industrial and residential purposes. Specifically, a carpet-tile with tactile surface formed of high denier yarns and its method of production are disclosed.
BACKGROUND OF THE INVENTION
Visually impaired persons acquire the skill of navigating in public areas via the sense of touch and hearing. Tactile warning surfaces are often employed in public places such as sidewalks, pavements, building hallways and staircases, walkway surfaces and pedestrian crossings, to guide and alert visually impaired people of the area they are entering. Tactile warning surfaces are generally textured surfaces that can be felt by touch, i.e. with feet, while walking or stepping on these surfaces, providing tactile cues to the person entering the region or surface. These surfaces are usually distinguished from normal surfaces by integrating truncated domes, cones, bars or strips,that essentially rise above the normal surface to provide a tactile sensation.
Traditionally, tactile surfaces have been created using techniques such as surface forming, deposition and etching. In surface forming, during the preparation of the surface a distinct pattern is created on the surface, such as stamping a concrete floor while laying the concrete to create patterns. Etching includes removing material from the surface using abrasives and the like, to create a distinct pattern. Deposition method includes deposition of materials on the surface, such as rubber, metals, plastic, that cure into different shapes like domes, cones, bars and strips. An issue with such techniques is that the patterns formed to provide tactile cue may not be uniform and can cause tripping of the person walking on such surfaces.
Currently, polyurethane and ceramic based tactile paving tiles are commercially available, with distinct patterns that are prepared using precise techniques. These tiles can be placed on previously constructed surfaces or walkways.
US20080107481 discloses an elongated tactile tile comprising multiple rows of elongated blisters with alternating rows offset, wherein the tiles are formed of a polyurethane casting resin to provide specific shape and configuration.
US20040067336A also discloses a tactile tile having a flat plate with a plurality of raised areas, said plate and raised areas comprised of polyurethane.
US5302049A provides a tile made of thermosetting resin for positioning on walkways, crosswalks and other areas of pedestrian traffic, for providing direction and warning to visually handicapped persons, wherein the tile includes a flat plate having top and bottom surfaces and an array of raised bumps coupled and formed integrally with the top surface of the plate, and projecting upward therefrom in a tactile pattern for providing tactile information.
US20040067336 discloses a rolled-up mat made from recycled tire-cord comprising tactile elements including rectangular array of truncated raised domes, aligned in horizontal rows and vertical columns of the mat.
Above disclosed tactile warning signs are prepared on hard surfaces or pre-installed pavements and are installed mostly in public spaces. Further, a major issue with such tactile patterns designed on sidewalks or walkways is that these materials are made of concrete, plastic etc. and there is high chance of breakage due to degradation, or collision with some object. Further, predesigned tactile tiles, if not properly installed, can trap air during installation, leading to breakage, and frequent replacements, which is time consuming and labor intensive.
Identifying the drawbacks present in traditional tactile warning surfaces, there is a necessity to produce tactile surfaces which are soft in nature, aesthetically pleasing, as well as can be used in both commercial and residential spaces.
U.S. Pat. No. 4,620,816 discloses a bipedal guidance system for permitting a person whose vision is impaired to continuously know his or her location with respect to the boundaries of an area having a walking surface and the spatial dimension of the area traversed. The guidance system comprises a plurality of tactile stimuli having predetermined physical characteristics distributed over substantially the entire walking surface. Typically, the tactual stimuli comprise a gradient of individual stimuli embossed within the walking surface and comprise studs which are generally cylindrically shaped and extend generally vertically upward. It also discloses the use of different types, heights or piles of carpet, spheres or semispheres, embedded pebbles or the like to form tactile surfaces. Likewise, stimuli of different shapes, for example, cross shaped, T-shaped, X-shaped, or the like, are also disclosed. While this disclosure provides significant details on at least 5 types of tactile or tactual stimuli and patterns for the same, there is no disclosure on how such patterns can be used to provide similar tactile cues to visually impaired persons in a closed environment, such as by using carpet-tiles that can provide similar tactile stimuli and cues. Barring one reference to use of piles of carpet, nothing herein teaches or suggests the preparation of carpet-tiles with tactile surface, such as those claimed herein.
U.S. Pat. No. 4,010,302 discloses carpet-tile including a tufted carpet facing portion including a stiffening and stabilizing layer, such as a primary backing layer and a glass fiber layer, in which the tufted carpet portion is embedded. The backing portion also includes a stiffening and stabilizing layer, such as a glass fiber layer. Interposed between the facing and backing portions is a resilient thermoplastic material made of polyvinyl chloride. The unitary carpet-tile of this disclosure is a tufted carpet that was designed to provide dimensional stability, stiffness, improved floor hugging properties during periods of concentrated stress, with flame retardance and low smoke emission properties. Nothing therein provides any teaching, suggestion or motivation to prepare carpet-tiles that provide tactile stimuli for the visually impaired, which aids in their safe movement in a defined space.
The present disclosure provides tactile structure to a soft surface, thereby allowing the provision of a tactile stimuli from a soft floor, such as that covered by a carpet having a high carpet face weight.

OBJECTIVE OF THE INVENTION
It is an object of the present disclosure to provide an aesthetically pleasing and soft textured tactile surface for guiding visually impaired people.
Another object of the present disclosure is to provide a soft textured tactile surface on a carpet-tile that mimics the conventional hard tactile surfaces, without causing any physical harm to the person.
Yet another object of the present disclosure is to provide a versatile carpet-tile having a tactile surface that can be customized in different patterns, dimensions and shape as per user requirement, with a view to provide the tactile stimuli necessary for safe movement of visually impaired persons.
Still another object of the present disclosure is to provide a carpet-tile with tactile surface that can be anchored to any surface, including but not limited to wood, ceramic floors, concrete and the like.
A further object of the present disclosure is to provide a carpet-tile having tactile structure that can be installed in, including but not limited to, commercial spaces, industrial areas and residential buildings.
SUMMARY OF THE INVENTION
In an aspect of the present disclosure, there is provided a carpet-tile for guiding visually impaired persons having a top surface, a bottom surface and parallel sides, wherein the said top surface comprises (a) tufted, low-lying elements made from a plurality of multiple-ply synthetic yarns with a denier ranging from 900 to 3600; and
(b) tufted, protruding high-lying elements made from a plurality of multiple-ply synthetic yarns with a denier ranging from 900 to 4800,
wherein the low-lying and high-lying elements alternate with one another to form a tactile surface.
In preferred embodiments, the tactile surface comprises an array of (a) tufted, low-lying elements having a plurality of 2-ply to 4-ply nylon yarn of 900 denier to 1800 denier and (b) tufted, protruding high-lying elements having a plurality of 2-ply to 4-ply nylon yarn of 900 denier to 1800 denier, alternating with one another.
In an aspect of the present disclosure, the synthetic yarn may be selected from the group consisting of nylon, polypropylene, polyethylene terephthalate (PET), poly(trimethylene terephthalate) (PTT), polybutylene terephthalate (PBT), in virgin or recycled form, or a combination thereof. In preferred embodiments, the synthetic yarn is nylon.
In another aspect of the present disclosure, the multiple-ply synthetic yarn comprises 2-ply, 3-ply, 4-ply, 5-ply, 6-ply, 7-ply or 8-ply constructions. In preferred emboduments, the yarn is a 2-ply to 4-ply yarn.
In another aspect of the present disclosure, the said elements of the tactile surface are embedded on a primary backing layer.
In another aspect of the present disclosure the primary backing layer comprises a non-woven material made of polyethylene terephthalate (PET), polypropylene, polyester, in virgin or recycled form, or a combination thereof. In preferred embodiments, the primary backing layer is a non-woven polyethylene terephthalate layer.
In another aspect of the present disclosure the primary backing layer comprises a woven material made of polyethylene terephthalate (PET), polypropylene, polyester, in virgin or recycled form, or a combination thereof. In preferred embodiments, the primary backing layer is a woven polyethylene terephthalate layer.
In yet another aspect of the present disclosure, the carpet-tile further comprises a pile surface, wherein the pile surface is coated with a functional finishing agent. Pile is the raised surface or nap of the synthetic yarn, consisting of upright loops or strands of yarn, also referred to as pile yarn. In an aspect of the present disclosure, the functional finishing agent is applied to the synthetic yarn either through the addition of functional additives during extrusion process of filaments. In another embodiment, the functional finishing agent is applied at the finishing stage through coating or spraying of filaments.
In another aspect of the present disclosure, the carpet- tile further comprises a primary coat layer below the primary backing, made of ethylene vinyl acetate, styrene-butadiene rubber (SBR), cross-linked SBR (X-SBR), acrylic-based latex, or a combination thereof.

In further aspect of the present disclosure, the carpet-tile comprises a secondary backing layer, comprising a reinforcement layer of a thermoplastic elastomer copolymer or thermoplastic polymer, and a stabilizing layer of glass fiber. The thermoplastic elastomer copolymer may be selected from thermoplastic polyolefin, thermoplastic urethane, thermoplastic copolyester, or a combination thereof. The thermoplastic polymer may be selected from ethylene vinyl acetate, acrylic based latex and mixtures thereof. In preferred embodiments, the reinforcement layer is made of ethylene vinyl acetate.

In one aspect of the present disclosure, the the secondary backing layer further comprises a coating of a filler-reinforced thermoplastic polymer.

In yet another aspect of the present disclosure, the secondary backing layer further comprises a coating of polyvinyl chloride, a thermoplastic elastomer copolymer, or a combination thereof. In a preferred embodiment, the secondary backing layer comprises a coating of polyvinyl chloride.

In a still further aspect of the present disclosure, the bottom surface has an insulated cushion backing made of at least one material selected from the group consisting of polyethylene terephthalate (PET), recycled polyethylene terephthalate, synthetic rubber, polyurethane, recycled polyurethane, ethylene vinyl acetate (EVA), or a combination thereof. In preferred embodiments, the bottom surface has an insulated cushion backing made of polyethylene terephthalate.

In one embodiment, the carpet-tile has a carpet face weight in the range of about 25 oz to about 65 oz. In a preferred embodiment, the carpet-tile has a carpet face weight in the range of about 50 to about 65 oz. In another embodiment, the carpet-tile has a face weight of about 55oz to about 60 oz.

In another aspect of the present disclosure, there is provided a method of producing a carpet-tile having a tactile surface, comprising the steps of :
(i) extruding synthetic yarns with a fineness ranging from 900 denier to 2400 denier;
(ii) multiple-plying 900 denier yarns and 2400 denier yarns separately at 70 to 150 twists per meter to produce a plurality of multiple-ply 900 denier yarns and multiple-ply 2400 denier yarns, respectively;
(iii) heat-setting the yarns prepared in step (ii) at a predetermined temperature ranging from 125°C to 145°C;
(iv) tufting the heat-set yarns obtained in step (iii) into a desired pattern on a primary backing layer to form a tactile surface of the carpet-tile;
(v) applying a functional finishing agent on the tufted tactile surface obtained in step (iv);
(vi) applying a reinforcement layer comprising a coating of copolymer resin to the backside of the tufted tactile surface obtained in step (v);
(vii) applying a first layer of secondary backing on the backside of the tactile surface obtained in step (vi), comprising a thermoplastic polymer or thermoplastic elastomer copolymer, further reinforced with a glass fiber stabilizing layer;
(viii) applying a second layer of secondary backing, comprising a thermoplastic polymer or thermoplastic elastomer copolymer, to the backside of the tactile surface obtained in step (vii);
(ix) providing a coating of polyvinyl chloride, a thermoplastic elastomer copolymer, or a combination thereof to the backside of the tactile surface obtained in steps (vii) and (viii);
(x) preparing a bottom surface by providing an insulated cushion backing made of at least one material selected from the group consisting of polyethylene terephthalate (PET), recycled polyethylene terephthalate, polyurethane, recycled polyurethane, synthetic rubber, or a combination thereof;
(xi) adhesively bonding the bottom of the tactile surface obtained in step (ix) with the top surface obtained in step (x) to form a carpet; and
(xii) cutting the carpet into tiles to obtain tactile carpet-tiles.
In yet another aspect of the present disclosure, there is provided a method of production of carpet-tile having a tactile surface comprising the steps of :
(i) extruding nylon yarns with fineness of 900 denier to 2400 denier;
(ii) plying two to four yarns separately at 120 twists per meter to produce a plurality of 2-ply to 4-ply nylon yarns of 900 denier to 2400 denier and a plurality of 2-ply to 4-ply nylon yarns of 900 denier to 2400 denier;
(iii) heat setting the yarns prepared in step (ii) at 125°C for 60 seconds;
(iv) tufting the heat set yarns obtained in step (iii) into a desired pattern on a primary backing layer to form a tactile surface of the carpet-tile;
(v) applying a functional finishing agent on the tufted tactile surface obtained in step (iv);
(vi) applying a reinforcement layer comprising a coating of thermoplastic copolymer on the backside of the tufted tactile surface obtained in step (v);
(vii) applying a first layer of the secondary backing on the backside of the tactile surface obtained in step (vi), comprising a thermoplactic polymer or a thermoplastic elastomer polymer, further reinforced with a glass fiber stabilizing layer;
(viii) applying a secondary layer of the secondary backing, comprising a thermoplastic polymer or thermoplastic elastomer copolymer, to the backside of the tactile surface pbtained in step (vii)
(ix) providing a coating to the backside of the tufted tactile surface obtained in steps (vii) and (viii) with an agent selected from polyvinyl chloride, recycled polyvinyl chloride, thermoplastic polyolefin and mixtures thereof;
(x) preparing a bottom surface by providing an insulated cushion backing made of agents selected from polyethylene terephthalate (PET), recycled polyethylene terephthalate, polyurethane, recycled polyurethane, synthetic rubbers and combinations thereof,
(xi) adhesively bonding the bottom of the tactile surface obtained in step (ix) with the top surface obtained in step (x) to form a carpet; and
(xii) cutting the carpet into tiles to obtain the tactile carpet-tiles.
DETAILED DESCRIPTION OF THE INVENTION
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
Unless the context indicates otherwise, it is specifically intended that the various features of the invention described herein can be used in any combination.
Moreover, the present invention also contemplates that in some embodiments of the invention, any feature or combination of features set forth herein can be excluded or omitted.
All publications, patent applications, patents, and other references mentioned herein are incorporated by reference herein in their entirety for all purposes.
As used herein, “a,” “an,” or “the” can mean one or more than one.
In the following description, terms such as top, bottom, parallel and the like, are used solely for the purpose of clarity, and should not be taken as words of limitation.
The terms “tactile surface”, “tactile structure”, “tactual surface”, “tactual structure” may be used alternatively, but have the same meaning, and describe the specific tufting conducted to provide an elevated surface or structure on the carpet-tile that can be felt when touched, and which elevated surface is created in patterns or designs that help provide the desired tactile stimuli to visually impaired persons, to assist them in moving around safely in an area or environment.
As discussed in the background of the invention, conventional tactile structures and commercially available tiles have several drawbacks. The inventors of the present disclosure have therefore addressed the need for development of tactile surfaces that are soft in nature, are aesthetically pleasing and which can be used to provide the necessary tactile stimuli to visually impaired persons, in both commercial and residential spaces.
Carpet-tiles are a new genre of fashion statement combined with functionality for use in commercial spaces, as well as in residential areas.
Carpet-tiles and their process of manufacturing is well known in the art, and is disclosed in various documents. US3402094A merely discloses tufts that uniformly rise over a backing layer, possibly with the intention to create a uniform soft surface, but does not provide any detail on creating patterns that provide tactile stimuli. WO2009059366A1, which discloses carpet-tiles but focuses more on pre-coating of the tiles using at least one copolymer derived from an acrylic or methacrylic monomer and a styrenic monomer, and at least one copolymer derived from an acrylic ester and a methacrylic ester, does not teach carpet-tiles with defined patterns that provide tactile stimuli. US5834087 discloses a tile carpet comprising a sealer (or precoat) layer of a novel hot-melt type composition low in fumability (fuming property) and superior in a sealing (or precoating) effect and backing layers of a composition low in fumability. This tile carpet has a backward warp (warpage) to permit the carpet to come into close contact with the floor surface easily without leaving any gap and is thus superior in shape stability. It does not teach or suggest the tactile structured carpet-tile disclosed and claimed herein. JP 4166270 relates to a method of forming a carpet-tile having a polymer backing, the polymer backing preferably being made in-line without precuring the polyurethane-forming composition. It does not teach or disclose carpet-tiles with tactile structures for providing stimuli to the visually impaired. Thus, while carpet-tiles, the methods for making them, the components of the carpet-tiles and their materials of construction are known in the art, there is no disclosure on carpet-tiles disclosed and claimed herein.
Carpet-tiles have also been used for a while now, and have typically been placed on the floor without use of any adhesives. Tiles which are not adhesively adhered to the floor (known as free-lay tiles) are dimensionally unstable, particularly when subjected to concentrated stress, thereby making them impractical and commercially non-viable. Prestressing the carpet-tiles during manufacture to overcome the dimensional stability problem has been tried. A pre-stressed carpet-tile can be manufactured, for example, with a dome-type of orientation in which the center of the tile is slightly higher than all of the corners. While such a construction is purported to reduce dimensional instability, particularly under concentrated stress, the carpet-tiles of this type do not lie flat and tend to form exaggerated domes upon use, finally making them commercially unsatisfactory. Further, there is a need to develop stable carpet-tiles that can effectively provide tactile stimuli to enable visually impaired persons to get the required cues for safe movement.
Accordingly, the inventors of the present disclosure have developed carpet-tiles having tactile surfaces that are soft in nature, and can be used both in commercial as well as residential spaces. The tactile surface of the carpet-tiles of the present disclosure is prepared with high denier yarn, attributing to soft nature of the tactile surface. This is essential to avoid any physical harm that can be caused by tripping over or stumbling due to hard tactile surfaces. The carpet-tiles of the recent disclosure having a tactile structure consist of a primary backing layer, a reinforcing layer and a stabilizing layer.
As used herein, the term ‘tufting’ is used as the term is conventionally used in textile industry, involving inserting yarn or fibres into a backing material to create a looped or piled surface. The loops are used to add texture and dimension to the fabric, depending on various parameters employed, and thereby provide a textured pattern that rises above the backing layer, creating a surface that provides tactile stimuli to the visually impaired.
As used herein, the term “high-low” is used to denote the comparative height of the tufted yarn forming the tactile surface with respect to each other, on the carpet-tile.
As used herein, the term “multiple-ply” implies yarns made by twisting multiple strands of yarn together to form a thicker, stronger thread. For instance, ‘two-ply’ implies yarns made by twisting two single strands of yarn together to create a thicker, stronger thread, and may be conventionally represented as 1800/2, indicating a two-ply1800 denier yarn.
As used herein, the term “ pile surface” refers to visible surface of the carpet-tile consisting of the tufted yarns.
As used herein, the term “virgin” implies materials in their pure, unprocessed, native state as produced and “recycled polymer” implies a material that has been recycled from polymeric waste, such as plastic waste, using chemical or mechanical recycling methods known in the art.
As used herein, the term ‘denier’ is a unit used for filament yarn (continuous long fibres), indicating the weight of 9000m of yarn i.e., if 9000m filament yarn weighs 1g, the fineness of the yarn is 1 denier, and if 9000m filament yarn weighs 50g, the fineness of the yarn is 50 denier. A yarn with a lower denier number is finer, while a yarn with a higher denier number is thicker. In the present disclosure, high denier yarns are used to obtain the tactile surface on the carpet-tile. In one embodiment, the plied nylon yarn contains 69 filaments. In one embodiment, the plied nylon yarn contains 69 filaments. In one embodiment, the plied nylon yarn contains 126 filaments. In one embodiment, the plied nylon yarn contains 210 filaments. In one embodiment, the plied nylon yarn contains 360 filaments.
In one embodiment of the present disclosure, the carpet-tile has a top surface, a bottom surface and parallel sides. The top surface of the carpet-tile acts as a tactile surface. The tactile surface is built in a high-low construction/texture, such that there is an alternating array of low lying elements present on the base of the carpet-tile, and protruding high lying elements that raise above the surface of the carpet-tile. This high-low construction/texture is achieved by using yarns of different fineness that are embedded or tufted on a primary backing layer.
In an embodiment of the present disclosure, the low-lying elements comprise a plurality of multiple-ply synthetic yarns with a denier ranging from 900 to 3600 tufted together on the primary backing layer, and high lying elements comprise a plurality of multiple-ply synthetic yarns with a denier ranging from 900 to 4800. In an embodiment, low-lying elements comprise a plurality of 2-ply 1800 denier yarns tufted together on the primary backing layer, and high lying elements comprise a plurality of 2-ply 2400 denier yarns tufted together on the primary backing layer. This implies 9000 metres of the yarn which is used for preparing the low-lying elements of the present disclosure weighs 1800 gram, and 9000 metres of the yarn used for preparing the high lying elements of the present disclosure weighs 2400 yarns. In another embodiment of the present disclosure, low-lying elements comprise a plurality of 3-ply 1800 denier yarns tufted together on the primary backing layer, and high lying elements comprise a plurality of 3-ply 2400 denier yarns tufted together on the primary backing layer. In yet another embodiment of the present disclosure, low-lying elements comprise a plurality of 4-ply 1800 denier yarns tufted together on the primary backing layer, and high lying elements comprise a plurality of 4-ply 2400 denier yarns tufted together on the primary backing layer. In still another embodiment of the present disclosure, low-lying elements comprise a plurality of 5-ply 1800 denier yarns tufted together on the primary backing layer, and high lying elements comprise a plurality of 5-ply 2400 denier yarns tufted together on the primary backing layer. In further embodiment of the present disclosure, low-lying elements comprise a plurality of 6-ply 1800 denier yarns tufted together on the primary backing layer, and high lying elements comprise a plurality of 6-ply 2400 denier yarns tufted together on the primary backing layer. In another embodiment of the present disclosure, low-lying elements comprise a plurality of 7-ply 1800 denier yarns tufted together on the primary backing layer, and high lying elements comprise a plurality of 7-ply 2400 denier yarns tufted together on the primary backing layer. In yet another embodiment of the present disclosure, low-lying elements comprise a plurality of 8-ply 1800 denier yarns tufted together on the primary backing layer, and high lying elements comprise a plurality of 8-ply 2400 denier yarns tufted together on the primary backing layer.
The high-low construction/texture can be prepared in any design and pattern by tufting yarns of different fineness, thereby making it customizable to user requirement. Unlike conventional tactile surfaces, this aspect of the present disclosure adds to producing aesthetically pleasing surfaces in accordance with the specifications provided by the user.The yarns forming the tactile surface of the carpet-tile can be made from a number of natural or synthetic fibres known in the art. Typically, there are two main types of yarns, spun and filament. The yarns of the present disclosure are preferably made of synthetic filaments selected from nylon, polypropylene, polyethylene terephthalate (PET), poly(trimethylene terephthalate) (PTT), polybutylene terephthalate (PBT), in virgin or recycled form, or a combination thereof. In a preferred embodiment, the synthetic yarns are made of nylon filaments.
The carpet-tile comprises of a primary backing layer that is usually a tufted fibrous layer that may be prepared by feeding the primary backing material to a conventional tufting machine which tufts fibres through interstices in the material. Tufting is typically performed in a manner such that the resulting tufts protrude from the underside face, with back stitches that hold the tufts in place on the topside of the material during processing. The protrusion of the tufts is designed to provide patterns that act as the tactile stimuli for the visually impaired.
In one embodiment of the present disclosure, the primary backing layer can be made of any woven and non-woven material known in the art. The primary backing layer may be made of polyethylene terephthalate (PET), polypropylene, polyester, in virgin or recycled form, or a combination thereof. Preferably, the primary backing layer of the present disclosure comprises non-woven polyethylene terephthalate (PET). The backing layer acts as a base or support onto which the yarn can be tufted.Once the yarns are tufted onto the primary backing layer, the pile surface is coated with a layer of functional finishing agent, applied to the synthetic yarn either through the addition of functional additives during extrusion or through coating or spraying during the extrusion process of filaments or at the finishing stage of the tiles. The functional finishing agents may include, but not limited to anti-staining agents incluing water, stain and oil repellants, antimicrobial protection, softness imparting agents, shape stabilizatig agents, flame retardats, UV protection agents, durable press antistatic agents, soil-resistant agents and the like. These finishing agents can be applied to carpet-tiles using chemical or mechanical methods known in the art. In a preferred embodiment, the pile surface is coated with a layer of anti-staining agent. The anti-staining agents are typically fluorinated chemicals, conventionally used in the art. Anti-staining properties may also be achieved through use of common materials such as nylon fibers that are treated to be stain resistant, polyester fibers that are naturally resistant to water-based stains, olefin (polypropylene) fibers that are resistant to water-based stains and bleaching. Use of these fibers in the carpet-tiles of the present disclosure help repel liquids and prevent them from penetrating deeply into the carpet structure, thereby ensuring that the tactile structure on the carpet-tile is always available to effectively provide a tactile stimuli to the visually impaired.
In an ambodiment of the present disclosure, a primary coat layer or a reinforcement layer is applied below the primary backing. The primary coat layer may be selected from ethylene vinyl acetate, styrene-butadiene rubber (SBR), cross-linked SBR (X-SBR), acrylic-based latex, or a combination thereof. In preferred embodiments of the present disclosure, the primary coat layer is of ethylene vinyl acetate.

In another embodiment of the present disclosure, the carpet-tile comprises a secondary backing layer. The secondary backing layer is formed of two layers. The first layer is made of a primary material that is provided with a reinforcement layer of thermoplastic elastomeric copolymer or thermoplastic polymer, followed by a stabilizing layer of glass fiber. In another embodiment, a layer of nonwoven glass fiber is sandwiched between two polyvinyl chloride (PVC) layers to provide dimensional stability. In an embodiment of the present disclosure, the thermoplastic elastomer copolymer may be selected from thermoplastic polyolefin, thermoplastic urethane, thermoplastic copolyester, and combinations thereof. In another embodiment of the present disclosure, the thermoplastic copolymer may be selected from ethylene vinyl acetate, acrylic based latex and mixtures thereof. In a preferred embodiment of the present disclosure, thermoplastic copolymer of the reinforcement layer is selected from ethylene vinyl acetate, acrylic based latex and mixtures thereof. In one embodiment, thermoplastic copolymer of the reinforcement layer is ethylene vinyl acetate. In another embodiment, thermoplastic copolymer of the reinforcement layer is acrylic based latex. The reinforcement layer helps in providing strength and support to the carpet-tile. In a preferred embodiment of the present disclosure, the reinforcement layer comprising ethylene vinyl acetate (EVA) is used as a pre-coat. This pre-coat helps in efficiently bonding the tufts in position on the primary backing layer.
In one embodiment, a stabilizing layer of glass fiber is included to impart dimensional stability to the carpet-tile. It prevents the carpet-tile from elongation, stretching, shrinking or curling up under concentrated stress, such as when a visually impaired person uses a cane or stick to walk on these tiles. The layers also make the tiles durable in the long run by preventing deformation of the carpet-tile. This ensures prevention of curling up of ends of the carpet-tile, and prevents accidents that may otherwise occur.
In another embodiment of the present disclosure, the secondary backing layer is provided with a coating of a filler-reinforced thermoplastic polymer, constituting the second layer . A filler-reinforced thermoplastic polymer is a polymer that has been strengthened with a filler material. The filler material may include any material that is known in the art to produce filler reinforced polymer such as metal particles, carbon black, graphite fiber, metal oxide particles, glass and the like. The filler- reinforced thermoplastic polymer may be selected from polyvinyl chloride, recycled polyvinyl chloride, thermoplastic polyolefin and mixtures thereof. In preferred embodiments, the coating on the secondary backing layer is made of polyvinyl chloride.
In another embodiment of the present disclosure, the first and second layers of the the secondary backing layer is coated with a layer of polyvinyl chloride (PVC), a thermoplastic elastomer copolymer, or a combination thereof. The thermoplastic elastomer copolymer may be seleced from thermoplastic polyolefin, thermoplastic urethane, thermoplastic copolyester, or a combination thereof. In preferred embodiments, the secondary backing layer is coated with a PVC.The PVC layer imparts hardness to the texture of the tufted yarn so that the carpet-tile stays in place, and also imparts a tile-like-texture to the carpet.
The insulated cushion backing layer may be made of agents selected from polyethylene terephthalate (PET), recycled polyethylene terephthalate, synthetic rubber, polyurethane, recycled polyurethane, ethylene vinyl acetate (EVA) and combinations thereof. In one embodiment of the present disclosure, the carpet-tile has an insulated cushion backing layer comprising polyethylene terephthalate.
In an embodiment of the present disclosure, the carpet-tile comprising the tactile surface is anchored to a surface such as a wall, ceramic flooring, wood, concrete and the like, using methods known in the art. Such methods include, but are not limited to, using floor fixing adhesives, and drilling into the floor to fix the carpet-tiles with the help of anchoring screws. Floor fixing adhesives include pressure sensitive adhesives (PSA) that are ready-to-use adhesives and are viscous in nature, and are applied as a film. The basic formulation of a PSA comprises a base polymer, an adhesive resin and a plasticiser, and is commercially available.
Carpet face weight is the weight of the carpet's pile per square yard, measured in ounces (oz). It is a measure of how much yarn or fiber is used to create the surface of the carpet. Face weight is a useful way to compare two carpets that are similar. It must be noted that face weight only refers to the weight of the carpet's fibers, not the backing material. The total weight of a carpet includes both the backing and the fibers. A higher face weight usually indicates a more durable carpet. A good face weight for high-traffic areas is 40–60 oz per square yard, while 30–50 oz per square yard is good for low-traffic areas. Commercially available carpets for use in residential areas typically have a carpet face weight below 30 oz. Carpets with tactile structure that can provide stimuli to the visually impaired need to be sturdy and durable, while still being soft. As a result, the carpet face weight needs to be on the higher side. The carpet-tile of the present disclosure has carpet face weight in the range of about about 25 oz to about 65 oz. In a preferred embodiment of the present disclosure, the carpet face weight is in the range of about 50 oz to about 65 oz.
In an embodiment of the present disclosure, the carpet-tile comprising the tactile surface has a carpet face weight of 54 oz per cubic yard. This is different from commercially available carpet-tiles that have a lower face weight. The carpet-tile comprising the tactile surface of the present disclosure can be anchored to desired surfaces such as a floor, sidewalks, wood, concrete or an existing carpet-tile weighing 18-30 oz per cubic yard to produce the tactile stimuli, to guide the visually impaired. Anchoring can be done using methods known in the art, such as drilling the floor and anchoring via a screw, or by using adhesives.
The carpet-tile of the present disclosure typically has a length of about 100cm to about 150cm, a width of about 20cm to about 25cm and a height of about 7mm to about 8mm. Several carpet-tiles of this dimension are laid in a desired pattern, anchored to a surface, to provide tactile guidance to the user. The yarn pile of protruding high-lying tactile elements has a pile height of at least about 5mm, while the low-lying elements remain on the base of the top surface of the carpet-tile. This implies that the protruding high-lying elements on the top surface of the carpet-tile are higher than about 5mm or more, than that of the low-lying elements, thereby providing a high-low tactile texture.
In a preferred embodiment of the present disclosure, the primary backing layer has a thickness of at least about 0.1mm, the reinforcement layer has a thickness of at least about 0.25mm, the stabilizing layer has a thickness of at least about 0.1mm, the PVC coating layer has a thickness of at least about 0.25 mm and the insulated cushion backing has a thickness of at least about 1.2mm.
In another embodiment of the present disclosure, there is provided a method of production of carpet-tile having a tactile surface. The tactile surface of the carpet-tile is made of synthetic yarns of different deniers that are stitched/tufted together in a manner effective to achieve a high-low construction/texture, resulting in distinct yarn heights that mimic a hard surface on which visually impaired people can walk on and decipher the stimuli.
The method of producing the carpet-tile having the tactile surface of the present dislcosure, comprises the following steps:
(i) extruding synthetic yarns with a fineness ranging from 900 denier to 2400 denier;
(ii) multiple-plying 900 denier yarns and 2400 denier yarns separately at 70 to 150 twists per meter to produce a plurality of multiple-ply 900 denier yarns and multiple-ply 2400 denier yarns, respectively;
(iii) heat-setting the yarns prepared in step (ii) at a predetermined temperature ranging from 125°C to 145°C;
(iv) tufting the heat-set yarns obtained in step (iii) into a desired pattern on a primary backing layer to form a tactile surface of the carpet-tile;
(v) applying a functional finishing agent on the tufted tactile surface obtained in step (iv);
(vi) applying a reinforcement layer comprising a coating of copolymer resin to the backside of the tufted tactile surface obtained in step (v);
(vii) applying a first layer of secondary backing on the backside of the tactile surface obtained in step (vi), comprising a thermoplastic polymer or thermoplastic elastomer copolymer further reinforced with a glass fiber stabilizing layer;
(viii) applying a second layer of secondary backing, comprising a thermoplastic polymer or thermoplastic elastomer copolymer, to the backside of the tactile surface obtained in step (vii);
(ix) providing a coating of polyvinyl chloride, a thermoplastic elastomer copolymer, or a combination thereof to the backside of the tactile surface obtained in steps (vii) and (viii);
(x) preparing a bottom surface by providing an insulated cushion backing made of at least one material selected from the group consisting of polyethylene terephthalate (PET), recycled polyethylene terephthalate, polyurethane, recycled polyurethane, synthetic rubber, or a combination thereof;
(xi) adhesively bonding the bottom of the tactile surface obtained in step (ix) with the top surface obtained in step (x) to form a carpet; and
(xii) cutting the carpet into tiles to obtain tactile carpet-tiles.
In a highly preferred embodiment, the present disclosure provides a tactile carpet-tile comprising (i) a primary non-woven backing layer of polyethylene terephthalate, wherein the tactile structures are provided on the backing layer by plying 69 filaments of 2-ply 1800 denier yarns and 2-ply 2400 denier yarns at 120 twists per meter, and tufting the yarns after heat setting them at 125°C for 60 seconds, followed by coating the pile surface comprising the tactile structures with anti-staining agent, a primary coating of ethyl vinyl acetate below the primary backing layer and supporting the primary backing layer with a first layer of secondary backing comprising reinforced ethylene vinyl acetate (EVA) layer and a layer of glass fiber, followed by a second layer of seconday backing comprising filler-reinforced thermoplastic polymer , with a layer of PVC coated on the first and second layers of the secondary backing, and (ii) a bottom surface layer made of an insulated cushion layer of polyethylene terephthalate, wherein the primary backing layer supported by the secondary backing layer and the bottom surface layer are adhesively bonded to obtain tactile carpet rolls that are cut into carpet-tiles of desired size and shape. The tactile carpet-tile of this embodiment has a carpet face weight of 57 oz.
The present disclosure also provides a method of production of carpet-tile having a tactile surface comprising the steps of :
(i) extruding nylon yarns with fineness of 900 denier to 2400 denier;
(ii) plying two to four yarns separately at 120 twist per meter to produce a plurality of 2-ply to 4-ply nylon yarns of 900 denier to 2400 denier and a plurality of 2-ply to 4-ply nylon yarns of 900 denier to 2400 denier;
(iii) heat setting the yarns prepared in step (ii) at 125°C for 60 seconds;
(iv) tufting the heat set yarns obtained in step (iii) into a desired pattern on a primary backing layer to form a tactile surface of the carpet-tile;
(v) including an anti-stain agent on the tufted tactile surface obtained in step (iv)
(vi) applying a reinforcement layer comprising a coating of thermoplastic copolymer to the backside of the tufted tactile surface obtained in step (v);
(vii) applying a first layer of the secondary backing on the backside of the tactile surface obtained in step (vi), comprising a thermolastic polymer or a thermoplastic elastomer polymer reinforced with a glass fiber stabilizing layer
(viii) applying a secondary layer of the secondary backing comprising a thermoplastic polymer or a thermoplastic elastomer copolymer, to the backside of the tactile surface obtained in step (vii)
(ix) providing a coating to the backside of the tufted tactile surface obtained in step (vii) and step (viii) with an agent selected from polyvinyl chloride, recycled polyvinyl chloride, thermoplastic polyolefin and combinations thereof;
(x) preparing a bottom surface by providing an insulated cushion backing made of agents selected from polyethylene terephthalate (PET), recycled polyethylene terephthalate, polyurethane, recycled polyurethane, synthetic rubbers or a combination thereof,
(xi) adhesively bonding the bottom of the tactile surface obtained in step (ix) with the top surface obtained in step (x) to form a carpet; and
(xii) cutting the carpet into tiles to obtain the tactile carpet-tiles.
Specifically in the method of the present disclosure, nylon yarns comprising of 69 filaments with fineness of 1800 denier and 2400 denier are extruded at 270°C, in an extruding machine (such as that available from OerlikonTM).
Cabling is a mechanical process that upgrades yarn for carpet production. It involves twisting yarns together to create a cabled yarn or multi-fold yarn. Cabling can be done through methods known in the art. In an embodiment of the present disclosure, the yarns of different denier are separately plied in cabling machine, i.e. separate filaments obtained using two 1800 denier yarns and two 2400 denier yarns are twisted with 120 twists per meter. Post cabling, the cabled yarns are heat set at 125°C for about 60 seconds. Heat setting causes hardening of the yarn, which helps achieve the required texture without losing the strength of the yarn. The heat set yarns are then loaded into the creel of a tufting machine (such as TuftcoTM), where the yarns are passed individually through needles and then tufted on non-woven primary backing layer to provide the base for the yarns to be stitched together. SPI stands for stitches per inch, which is a measurement of carpet density. It indicates how many times a needle inserts a tuft into the carpet's backing as it moves one inch through the tufting machine. A higher SPI usually means more loops in the carpet and better quality. The present disclosure provides carpet with about 50 to about 65 stitches per 10cm.
The tufted yarn roll is then subjected to a coating machine where coating layer of ethylene vinyl acetate (EVA) is applied at 180°C. A sheet of glass fiber is then applied on top of the coating layer, followed by addition of a PVC layer at about 180°C to obtain a tile structure. The tiles are then cut in desired shape and size using a cutting machine. The invention is not limited to the shapes, sizes and/or designs that the tiles can be cut into, as that is known in the art, and can be achieved as per desire and knowledge of a skilled person.
EXAMPLES
Example 1
Recycled nylon chips and solution dyed master batch were used to make the carpet. 1800 denier and 2400 denier yarns having 69 filaments each denier were extruded. The yarns were then subjected to cabling to obtain 1800/2 denier and 2400/2 denier, with 120 twists per meter and twist direct was “S”. The 2400/2 two-plyed yarn was heat set at 125 degree Celsius and dwell time was 60 seconds. The heat set 2400/2 yarn was then tufted with 1800/2 denier yarn tufted onto a 120 grams per square meter (GSM) non-woven polyester primary backing, as per the desired design.
The tufting specification was as follows –
Pile Yarn-1 1800/2 denier, 138 Filament
Pile Yarn-2 2400/2 denier, 138 Filament
Pile Yarn GSM 54 oz
Backing 120 GSM Non-Woven Polyester
Machine Gauge 1/10 Loop
SPI 14.5

This was followed by coating, wherein the tufted fabric was pre-coated with topical finish (anti stain and anti soil) by a foaming process. The Pre coat GSM was 600. This was followed by a PVC coat with 2100 GSM, a 35 GSM glass fibre and a 300 GSM recycled cushion pad. Finally, the carpet thus obtained was dye cut to size of 25 cm X 100 cm, and packed for dispatch.
, Claims:We claim:
1. A carpet-tile for guiding visually impaired persons, comprising:
a top surface;
a bottom surface; and
a plurality of parallel sides;
where the top surface comprises:
(a) tufted, low-lying elements made from a plurality of multiple-ply synthetic yarns with a denier ranging from 900 to 3600; and
(b) tufted, protruding high-lying elements made from a plurality of multiple-ply synthetic yarns with a denier ranging from 900 to 4800, wherein the low-lying and high-lying elements alternate with one another to form a tactile surface.

2. The carpet-tile as claimed in claim 1, wherein the synthetic yarn is selected from the group consisting of nylon, polypropylene, polyethylene terephthalate (PET), poly(trimethylene terephthalate) (PTT), polybutylene terephthalate (PBT), in virgin or recycled form, or a combination thereof.

3. The carpet-tile as claimed in claim 1, wherein the multiple-ply synthetic yarn comprises 2-ply, 3-ply, 4-ply, 5-ply, 6-ply, 7-ply or 8-ply constructions.

4. The carpet-tile as claimed in claim 1, wherein the tactile surface is embedded on a primary backing layer.

5. The carpet-tile as claimed in claim 4, wherein the primary backing layer comprises a woven or non-woven material made of polyethylene terephthalate (PET), polypropylene, polyester, in virgin or recycled form, or a combinations thereof.

6. The carpet-tile as claimed in claim 1, further comprises a pile surface, wherein the pile surface is coated with a functional finishing agent, applied to the synthetic yarn either through the addition of functional additives during extrusion or through coating or spraying during the extrusion process of filaments or at the finishing stage of the tiles.

7. The carpet as claimed in claim 1, further comprising a primary coat layer below the primary backing, made of ethylene vinyl acetate, styrene-butadiene rubber (SBR), cross-linked SBR (X-SBR), acrylic-based latex, or a combination thereof.

8. The carpet-tile as claimed in claim 1, further comprising a secondary backing layer, wherein the primary material is provided with a reinforcement layer of a thermoplastic elastomer copolymer or thermoplastic polymer, followed by a stabilizing layer of glass fiber.

9. The carpet-tile as claimed in claim 8, wherein the thermoplastic elastomer copolymer is selected from a group consisting of thermoplastic polyolefin, thermoplastic urethane, thermoplastic copolyester, or a combination thereof.

10. The carpet-tile as claimed in claims 8, wherein the secondary backing layer further comprises a coating of a filler-reinforced thermoplastic polymer.

11. The carpet-tile as claimed in claim 1, wherein the bottom surface is an insulated cushion backing made of at least one material selected from the group consisting of polyethylene terephthalate (PET), recycled polyethylene terephthalate, synthetic rubber, polyurethane, recycled polyurethane, ethylene vinyl acetate (EVA), or a combination thereof.

12. The carpet-tile as claimed in claim 1, wherein the carpet face weight ranges between about 25 oz and about 65 oz.

13. A method of producing a carpet-tile having a tactile surface, comprising the steps of :
(xiii) extruding synthetic yarns with a fineness ranging from 900 denier to 2400 denier;
(xiv) multiple-plying 900 denier yarns and 2400 denier yarns separately at 70 to 150 twists per meter to produce a plurality of multiple-ply 900 denier yarns and multiple-ply 2400 denier yarns, respectively;
(xv) heat-setting the yarns prepared in step (ii) at a predetermined temperature ranging from 125°C to 145°C;
(xvi) tufting the heat-set yarns obtained in step (iii) into a desired pattern on a primary backing layer to form a tactile surface of the carpet-tile;
(xvii) applying a functional finishing agent on the tufted tactile surface obtained in step (iv);
(xviii) applying a reinforcement layer comprising a coating of copolymer resin to the backside of the tufted tactile surface obtained in step (v);
(xix) applying a first layer of secondary backing on the backside of the tactile surface obtained in step (vi), comprising a thermoplastic polymer or thermoplastic elastomer copolymer further reinforced with a glass fiber stabilizing layer;
(xx) applying a second layer of secondary backing, comprising a thermoplastic polymer or thermoplastic elastomer copolymer, to the backside of the tactile surface obtained in step (vii);
(xxi) providing a coating of polyvinyl chloride, a thermoplastic elastomer copolymer, or a combination thereof to the backside of the tactile surface obtained in steps (vii) and (viii);
(xxii) preparing a bottom surface by providing an insulated cushion backing made of at least one material selected from the group consisting of polyethylene terephthalate (PET), recycled polyethylene terephthalate, polyurethane, recycled polyurethane, synthetic rubber, or a combination thereof;
(xxiii) adhesively bonding the bottom of the tactile surface obtained in step (ix) with the top surface obtained in step (x) to form a carpet; and
(xxiv) cutting the carpet into tiles to obtain tactile carpet-tiles.