Title of Invention

"CARPET STRUCTURE METHOD OF MANUFACTURE THEREOF"

Abstract

The present invention provides a carpet structure which comprises a carpet layer, an intermediate layer of an adhesive of a predetermined thickness and a backing layer, said adhesive layer comprising a layer with intermediate pockets provided therein which act as sound dampeners and air cushions. The invention also relates to a method for the manufacture of the carpet structures and to an adhesive composition for use as an intermediate layer therein.

Full Text

MULTI-LAYER FLOOR COVERING STRUCTURE AND METHOD OF MANUFACTURE THEREOF Field of the invention The present invention relates to a carpet with a novel structure and to a method for the manufacture thereof The present invention also relates to an adhesive composition for use as an intermediate layer in a carpet structure of the invention. Background of the invention Floor coverings such as carpets are manufactured through a series of separate processes that are typically carried out on separate manufacturing lines For example, a first line is used to produce a carpet material that is formed either by weaving textile yams to form a woven layer or by attaching tufts of textile material to a woven primary backing. In either case, a thin polymeric locking layer is coated to the backside. The output of this process is an unbacked or unfinished carpet material, which is then wound into a roll and transferred to a second processing line. In the second processing line, a layer of vinyl material is added to the back of the carpet to fill the voids in and between the fibers and to provide a uniform surface for attachment of a backing layer. This vinyl layer is typically formed by applying an uncured layer of vinyl on a belt, pressing the unbacked carpet material onto the vinyl sheet and passing the assembly through an oven to cure the vinyl layer in place. Once the vinyl layer has been cured, the carpet/vinyl is separated from the belt and again wound into a roll for transfer to a third processing line where a backing layer is adhered to the vinyl layer. This typical manufacturing process is highly inefficient in that it requires a separate process line for the vinyl casting process. In addition, the method used to apply the vinyl layer requires the use of a relatively thick layer of vinyl. The cost of virgin vinyl is such that a reduction in the thickness of this layer would result in a significant overall cost reduction for the final product. Another problem of most prior art carpets is that the level of adhesion is not sufficient to ensure that the backing layer does not separate from the carpet layer itself. It is another significant disadvantage that the carpets in question do not also possess strength to resist wear and tear. US Patent 6406574 discloses a method for manufacturing a vinyl-backed carpet is described wherein the carpet is assembled in a single continuous finishing line. The method includes the application of a vinyl plastisol reinforcing layer directly to the back of unfinished woven or tufted carpet material. The method allows the use of a thinner vinyl layer that results in savings hi material, processing steps, and energy required for curing. However, the strength of the carpet is not good. The method is also not applicable for small scale hand loom manufacturing of carpets. US Patent 6299961 discloses recyclable textile floor coverings for motor vehicles with a multi-layer structure and processes for their preparation. In particular, recyclable textile floor coverings for motor vehicles with a multi-layer structure include a foam layer, a separation layer, a heavy layer, and a textile carpet, wherein the adhesiveness of the separation layer with respect to the heavy layer is different than the adhesiveness of the separation layer with respect to the foam layer. In another embodiment, the separation layer is separably bonded to the heavy layer by spot bonding and/or is separably bonded to the foam layer by spot bonding. The separation layer allows separate recycling of the foam layer on one hand and the textile carpet including the heavy layer on the other hand. However, in this case, the use of several different layers does not contribute to the strength of the carpet. It is therefore important to devise carpet structures which while being multi-layered are also strong and do not require expensive equipment for manufacture. Objects of the invention It is therefore an object of the invention to provide a carpet structure which is strong, resilient, possesses dimensional stability and provides good cushioning effect over a period of time. It is another object of the invention to provide a carpet structure with good sound deadening capability. It is a further object of the invention to provide a method for the manufacture of the carpet structure of the invention which is inexpensive and does not require substantial equipment change and is applicable across both automated and manual carpet manufacture. It is a further object of the invention to provide a adhesive composition which enables strong adhesion between the carpet layer and the backing and acts as an intermediate layer with good resilience and adhesive strength. Summary of the invention Accordingly the present invention provides a carpet structure which comprises a carpet layer, an intermediate layer of an adhesive of a predetermined thickness and a backing layer, said adhesive layer comprising a layer with intermediate pockets provided therein which act as sound dampeners and air cushions. In one embodiment of the invention, the carpet layer is selected from woven carpet and a tufted carpet wherein the pile is on the outside and the fiber on the inside layer. In another embodiment of the invention, a plurality of air voids are provided in the intermediate layer in a predetermined pattern. In a further embodiment of the invention, a foam layer is provided as the backing layer. In yet another embodiment of the invention, the backing layer comprises ethylene propylene foam. In another embodiment of the invention, the primary backing and adhesive layer comprises a mixture of Neoprene, Aromatic hydrocarbon, and a Synthetic Resin and optionally a pigment. The composition comprises neoprene in an amount of 8 to 12 % by weight, the aromatic hydrocarbon in an amount of 88 to 80 % by weight and phenolic resin in an amount of 4 to 8 % by weight. In another embodiment of the invention, the aromatic hydrocarbon comprises toluene. In yet another embodiment of the invention, the synthetic resin comprises phenol formaldehdye resin. The invention also relates to a method for the manufacture of a carpet structure comprising carpet layer, an intermediate layer of an adhesive of a predetermined thickness and a backing layer, said adhesive layer comprising a layer with intermediate pockets provided therein which act as sound dampeners and air cushions, said method comprising forming a carpet layer in the form of a raw carpet from cotton/woolen/acrylic, coating said carpet layer with a primary adhesive paste to form an intermediate adhesive layer with air pockets provided therein, applying a secondary backing layer to intermediate layer. In one embodiment of the invention, the primary adhesive paste is applied mechanically or manually. In another embodiment of the invention, the air pockets are formed by a voids mesh is pasted with the carpet by applying the pressure on it and curing done at appropriate temperature and at low humidity. The present invention also relates to an adhesive composition for the use in creation of a adhesive layer for carpets, said composition comprising, Neoprene, Aromatic hydrocarbon, and a Synthetic Resin and optionally a pigment. The composition comprises neoprene in an amount of 8 to 12 % by weight, the aromatic hydrocarbon in an amount of 88 to 80 % by weight and phenolic resin in an amount of 4 to 8 % by weight. In another embodiment of the invention, the aromatic hydrocarbon comprises toluene. In yet another embodiment of the invention, the synthetic resin comprises phenol formaldehdye resin. The invention also relates to a novel synergistic adhesive composition for use as an intermediate layer in the manufacture of floor covering structures, said composition comprising Neoprene, Aromatic hydrocarbon, and a Synthetic Resin and optionally a pigment. The composition comprises neoprene in an amount of 8 to 12 % by weight, the aromatic hydrocarbon in an amount of 88 to 80 % by weight and phenolic resin in an amount of 4 to 8 % by weight. In another embodiment of the invention, the aromatic hydrocarbon comprises toluene. In yet another embodiment of the invention, the synthetic resin comprises phenol formaldehdye resin. The adhesive composition of the invention is a synergistic composition with improved and unexpected properties over the aggregate properties of the individual ingredients and is not a mere admixture. Brief description of die accompanying drawings Figure 1 is a pattern drawing of the floor covering structure of the invention. Detailed description of the invention Process parameters at which the method of the invention is carried out are given in Table 1 below: Table 1 Curing Conditions: 1. Temperature: 70° c to 80° c 2. Humidity: 40% Max 3. Rolling Pressure: 2 Kg/cm2 4. Curing Time: 3-4 Hrs. 5. Moisture Content: 38% Max The method of the invention is carried out manually by applying a roller or like device to cure the carpet structure after the application of the adhesive and the backing layers. The entire method can also be carried out mechanically. It is an advantage of the invention, that the method can be applied irrespective of whether the carpet manufactured is of synthetic material such as acrylic or natural material such as cotton and whether the carpet manufacture process is mechanised or manual. The pile height to intermediate layer thickness to backing layer thickness is preferably in the range given in Table 2 below Table 2 Sr. No.Pilc Height Intermediate Layer Thickness Backing Layer Thickness (Table Removed) The adhesive layer comprises a mixture of neoprene, an aromatic hydrocarbon such as toluene and a synthetic resin such as phenol formaldehyde resin. In order to improve the aesthetic appearance of the carpet intermediate layer, a pigment can also be added to the adhesive layer composition. Ingredients in the adhesive layer composition are preferably in the following amounts: Table 3: (Table Removed) Raw Carpet in form of Woven Carpet or Tufted Carpet (i.e., Pile on one side and fibrous on other side) is produced from Yam of Cotton/Woolen/Acrylic or other materials is coated with primary backing paste mechanically or manually. Air voids may be or may not be provided in the carpet. If air voids are required, a voids mesh is pasted with the carpet by applying the pressure on it and curing is done at suitable temperature and at low humidity. Secondary EP foam backing is provided to this intermediate layer by application of strong bond adhesive layer manually or mechanically subject to securing of air voids, which generates extra cushioning effect in the carpet. Table 4 below shows the advantages in performance of the carpets of the invention: Table 4 (Table Removed) We Claim: 1. A carpet structure which comprises a carpet layer, an intermediate layer of an adhesive of a predetermined thickness and a backing layer, said adhesive layer comprising a layer with intermediate pockets provided therein which act as sound dampeners and air cushions. 2. A carpet as claimed in claim 1 wherein the carpet layer is selected from woven carpet and a tufted carpet wherein the pile is on the outside and the fiber on the inside layer. 3. A carpet as claimed in claim 1 wherein a plurality of air voids are provided in the intermediate layer in a predetermined pattern. 4. A carpet as claimed in claim 1 to 3 wherein a foam layer is provided as the backing layer. 5. A carpet as claimed in claim 4 wherein the backing layer comprises ethylene propylene foam. 6. A carpet structure as claimed in claim 1 to 4 wherein the intermediate layer comprises a patterned structure made of neoprene, an aromatic hydrocarbon and a synthetic resin. 7. A method for the manufacture of a carpet structure comprising carpet layer, an intermediate layer of an adhesive of a predetermined thickness and a backing layer, said adhesive layer comprising a layer with intermediate pockets provided therein which act as sound dampeners and air cushions, said method comprising forming a carpet layer in the form of a raw carpet from cotton/woolen/acrylic, coating said carpet layer with a primary adhesive paste to form an intermediate adhesive layer with air pockets provided therein, applying a secondary backing layer to intermediate layer. 8. A method as claimed in claim 7 wherein the primary adhesive paste is applied mechanically or manually. 9. A method as claimed in claim 7 wherein the air pockets are formed by a voids mesh is pasted with the carpet by applying the pressure on it and curing done at appropriate temperature and at low humidity. 10. A method as claimed in claim 7 to 9 wherein the curing of the carpet structure is preferably carried out at a temperature in the range of 70° to 80°C, humidity of up to 40%, rolling pressure of about 2 Kg/cm2, curing time in the range of 3-4 Hrs., and moisture content of up to 38% 11. An adhesive composition for the use in creation of a adhesive layer for carpets, said composition comprising, Neoprene, Aromatic hydrocarbon, and a Synthetic Resin and optionally a pigment. 12. An adhesive composition as claimed in claim 11 wherein the composition comprises neoprene in an amount of 8 to 12 % by weight, the aromatic hydrocarbon in an amount of 88 to 80 % by weight and phenolic resin in an amount of 4 to 8 % by weight. 13. An adhesive composition as claimed in claim 11 or 12 wherein the aromatic hydrocarbon is toluene. 14. An adhesive composition as claimed hi claim 11 wherein the synthetic resin is phenol formaldehyde resin. 15. A carpet structure substantially as described hereinbefore and with reference to the accompanying drawing. 16. A method for the manufacture of a carpet structure substantially as described hereinbefore and with reference to the accompanying drawing. 17. An adhesive composition for use as an intermediate layer in a carpet structure substantially as described hereinbefore and with reference to the accompanying drawing.

Documents:

805-del-2002-abstract.pdf

805-del-2002-claims.pdf

805-del-2002-corrsepondence-others.pdf

805-del-2002-corrsepondence-po.pdf

805-del-2002-description (complete).pdf

805-del-2002-drawings.pdf

805-del-2002-form-1.pdf

805-del-2002-form-19.pdf

805-del-2002-form-2.pdf

805-del-2002-form-3.pdf

805-del-2002-gpa.pdf