Patent Application
20100178829
This invention relates generally to a composite fabric and a method and apparatus for manufacturing a composite fabric, especially suitable for apparel application, upholstery, bed and bath applications.
Conventional textile fabrics are produced mainly through weaving and knitting technology. This value chain starts from fiber selection and development/modification so as to bring them to a spinnable form. This is followed by spinning of the yarns. Many spinning technologies are known in the art. However, ring spinning is the most versatile and dominant one. Compact spinning is the latest advancement in this ring spinning technology. Spinning is followed by weaving or knitting process wherein yarns are interlaced or intermeshed together to form a fabric.
Woven fabrics are interlaced structures involving two series of threads i.e. warp and weft at right angles to each other. The fabric properties are governed by its constructional parameters like yarn count, thread density, yarn crimp, weave and area density which is a function of all other parameters. Fabrics are woven with variety of structures like plain, twills, ribs and combinations thereof. Woven fabrics find a wide range of applications as apparels like denims, bottom weights, shirting, ladies dress material etc. Compared to knitted fabrics, woven fabrics are well known for their graceful appearance, crease recovery and drape. But the properties like thermal insulation, water vapor permeability & air permeability are poor in these constructions because of compact structures resulting from the pressure of interlacing at the cross over points. In order to make these fabrics more functional with respect to insulation properties and water vapor transmission, wrinkle free, etc structural modifications need be done in combination with suitable additional materials/chemicals.
On the contrary, knitted fabrics are intermeshed structures, which are developed from a single source of yarn. They can be weft knitted or warp knitted. Since there is no axial alignment of threads in knitted fabrics they lack the gracefulness as in case of woven fabrics. Thus, the drape is poor and these fabrics are soft to handle. Most of these fabrics in use are weft knitted and preferred for next-to-skin inner garments or as casual wear. The crease recovery of these fabrics is also poor.
Thus, in order to improve aesthetics of these constructions without affecting their basic functionality, reinforcement may be provided which is loose in construction and has open fiber configuration. Knitted fabrics can find wide spread applicability with all desirable functional properties and dimensional stability as a formal wear.
Additional function can be introduced in a basic fabric through the structural modifications or through chemical finishes. While modifying the parent woven and knitted fabric structures, it should always be borne in mind that the basic properties should not be affected. The structure-property inter-relationships are so intense in textile materials, that one property cannot be altered in isolation from all other properties. Further, route of chemical finishes has a limitation of life of finish and also the fabric doesn't remain eco-friendly
Thus, the most appropriate approach is to achieve optimization with respect to all functional properties at the same time taking into consideration the economic aspects of production. A composite textile fabric is the best solution. While the composite structure results in better functionality, composite structures can be made out of combination of woven and/or knitted and for nonwoven fabrics or layers.
Nonwoven is a latest technology of forming fabric directly from fibers and/or filaments. It involves first step of preparation of web of fibers and/or filaments followed by the bonding of the fibers so as to form a fabric. Chemical bonding and thermal bonding are the known methods. Fabrics made through these processes are very stiff and lag in handle and feel and not suitable for any application next to human skin.
Known composite fabrics include at least one layer of a non-woven fabric added on as a fused or interlined layer on a base fabric made of a woven or knitted material. Some composite fabrics include a sandwiched non-woven layer in-between two woven, knitted or any other synthetic layers. However, both need to be produced separately in the beginning and then should be bonded together in a separate process either by using chemicals or by means of heat or by stitching. Also these layers always tend to behave as separate entities and the characteristics of the two layers may not be complementing each other. Additionally it is a long and expensive process to produce a composite fabric.
Thus, there exists a need for a composite fabric wherein (i) the fabric is soft and lofty and suitable apparel textile (ii) air permeability is excellent and controllable (iii) the fabric could be made using fibers which otherwise could not be made through conventional textile processes (iv) the fabric has improved tensile strength and bursting strength (v) throughput of the textile machine is improved (vi) obtains reduced value chain.
Further, conventional composite fabrics, methods and systems for manufacture of the same do not provide a fabric (i) wherein induced stresses in the fabric are substantially minimized without repositioning of the yarns and/or reduction in dimensions of the finished fabric (ii) hygienic and eco-friendly method of manufacturing a composite fabric (iii) a composite fabric whose strength and properties can be adjusted during manufacture so as to suit desired application (iv) a significantly wider range of application as against traditional textiles.
In an embodiment, a composite fabric comprises a base fabric made by weaving or knitting. A plurality of gaps is disposed in-between the fibers of the yarns of the base fabric. A plurality of functional fibers is entangled in the gap, with predetermined retention to the yarns of the base fabric.
In an embodiment, a composite fabric manufacturing apparatus comprises at least one first entanglement unit for stabilizing a base fabric. At least one second entanglement unit is provided for entangling a plurality of functional fibers into the yarns of the base fabric. The entanglement units are configured having a plurality of injectors and perforated drums operating at predetermined operating parameters so as to lock the functional fibers into the yarns of the base fabric.
In an embodiment, a composite fabric manufacturing method comprises stabilizing and forming gaps in-between fibers in the yarns of a base fabric using a fluid jet of predetermined first pressure. A plurality of functional fibers is entangled in the gaps using fluid jet of predetermined second pressure wherein the functional fibers are coupled to the yarns of the base fabric with predetermined retention.
Various embodiments of this invention provide a composite fabric. Further embodiments of this invention provide a method and apparatus for manufacturing a composite fabric. However, the embodiments are not limited and may be used in connection with various applications that will be described in later part of this specification.
In an example, the base fabric (1) may comprise a natural fiber such as, a cotton fiber, vegetable fiber, etc. However, the base fabric (1) may also include a synthetic fiber. Examples of functional fibers (7) may include outlast fiber (phase change fiber), lyocell (anti-microbial fiber), organic cotton (eco-friendly fiber), Cotton, bamboo (anti-microbial), regenerated fiber (viscose), nylon, silk, polyester, wool or any other functional fiber depending on the required properties and application of the composite fabric product.
In an embodiment, an entanglement unit (130) comprises at least one perforated drum (D1) with or without sleeve and at least a pair of injectors (132). This entanglement unit (130) stabilizes the base fabric (1) and delivers the base fabric (1) to the next entanglement unit (140). A compaction belt (150) is provided to combine and compact the stabilized base fabric (1) and the web (110) from the carding unit (90). This is followed by entanglement of the functional fibers from the web (110) into the base fabric (1) thus forming a composite fabric (5). This entanglement is done using a plurality of drums (D2-D4) and injectors (142, 152, 162) at predetermined operating parameters. This is followed by a squeezing unit (160) that squeezes and removes excess water from the composite fabric (5) thus formed and delivers the composite fabric to a drying unit (170). The drying unit (170) comprises a plurality of steam heated drying cans and/or air-heated drums. Thus dried composite fabric (5) is wound on to a composite fabric winder (190).
Furthermore, in an embodiment of the method of manufacturing a composite fabric, the repositioning/reorganizing of the fibers simultaneously opens out the yarn structure in the base fabric (1). The opening out of the yarn structure in the base fabric (1) increases the surface area to generate additional space among the fibers to accommodate functional fibers (7) for entanglement.
In some embodiments, the fibers in the yarns of base fabric (1) may be treated with chemicals such as, caustic soda, ammonia, etc so as to facilitate availability of extra space for the functional fibers (7) to reside into. The base fabric (1) with yarns made out of partly or fully with the synthetic fibers may be heat set to stabilize and some times initiate the preliminary yarn-to-yarn and fiber-to-fiber bonding.
In some embodiments, fibers, yarns and/or the base fabric (1) itself may be treated with chemical adhesives, binders, etc so as to activate the surfaces thereby facilitating improved entanglement strength.
In some embodiment, fibers, yarns and base fabric (1) may be treated with plasma so as to activate the surfaces thereby facilitating improved entanglement strength.
In general, the base fabric (1) is constructed lightly facilitating achievement of required properties in the composite fabric (5).
In an embodiment, the yarns (3) of the base fabric (1) are spun with low twist levels (3% to 6%) and/or with much shorter and coarser fibers. This enables more yarn diameter and more free space among the fibers of the yarns (3). This also helps in fiber movement and creation of additional space during entanglement and stabilization of the base fabric (1). This helps in entangling more proportion of functional fibers (7) into the gaps among the fibers in the yarns of the base fabric (1).
Thus stabilized base fabric (1) is laid with functional fibers (7) from the web (110) followed by compacting.
A series of fluid jets at predetermined pressure (example 60 bar up to 400 bar) is used for entanglement of functional fibers (7) from the web (110) with the base fabric (1). In the process, functional fibers (7) are systematically separated out from the web followed by pushing them preferably in a single fiber form into the gaps created among the fibers in the yarn. For those functional fibers (7), which do not get this opportunity, are assembled in a proper format followed by their entanglement with the already entangled functional fibers (7) and at the end amongst themselves. For example, the number of fluid jets is at least two. This step is followed to lock the functional fibers 7 into the gaps in-between the fibers of the yarns (3). A plurality of the functional fibers 7 is locked in-between the yarns and the functional fibers 7 are also mutually entangled.
The high-pressure fluid jet is impacted on the base fabric (1) such that the fluid jet penetrates into the fibers of the yarn (3). The penetrated fluid jet further gets reflected at substantially in all directions from the surface of the sleeve or the surface of the perforated drum (D1) through the fibers in the yarn (3). The fibers in the yarn (3) get reoriented/reorganized wherein during such repositioning/reorganization of the fibers, the fibers absorb the energy from the fluid jet and thereby get relieved of their stresses and also reach to the minimum energy position.
The wet base fabric (1) delivered by the entanglement unit (140) is uniformly squeezed so as to remove excess water and at the same time facilitate further pushing of partially pushed-in functional fibers (7) into the spaces still available in the yarns and in the base fabric (1). In case of surface activated base fabric (1), the squeezing helps in creating uniform bonding thereby improving entanglement strength. The squeezing helps in reducing the overall weight of the composite fabric being offered for the drying under a predetermined tension. This weight reduction and reduction of mobilizing agent like water enables the reduction of the possibilities of weakening of entanglement points before they are frozen during drying.
A plurality of functional fibers is entangled to the base fabric (1) from at least one side of the base fabric (1).
In an embodiment, the perforated drums (D1-D4) are covered with sleeves with predetermined openness (example 20% up to 80%). This is one of the factors to control the entanglement strength.
The length of the fluid jet (example 6 mm up to 12 mm) decides the entanglement strength. For example, lower the length of the fluid jet, the entanglement strength initially increases followed by more scattering of the functional fibers (7) due to severe reflection from the surface of the drum and the sleeve, with further reduction thereby resulting into reduction of the entanglement strength.
A vacuum slot (6 mm up to 14 mm) in the perforated drum (D1) decides the amount of reflection of the fluid jet from the surface of the sleeve or the perforated drum (D1) and thereby the entanglement strength.
In an embodiment, the number of jets per inch is in the range of 10 up to 120. The jet size is in the range of 0.07 mm up to 0.3 mm. The number of rows of jets is in the range from 1 up to 3. These parameters decide the way of entanglement and the entanglement strength.
In an embodiment, the through-put rate of 10 m/min up to 100 m/min decides the residence time of entanglement zone on the composite fabric (5) and thereby the entanglement strength.
In an embodiment, the number of passes through the entanglement unit (140) also decides the entanglement strength. For example, increased number of passes will result in improved entanglement strength to an optimum. Further additional passes start deteriorating the entanglement strength and also composite fabric (5) becomes more stiff comparable to paper material.
In an embodiment, in the entanglement unit (140), on drum (D4) another side of the composite fabric (5) is treated by at least a pair of high-pressure fluid jets (example 20 bar to 120 bar) and preset parameters (0.07 mm to 0.12 mm jet size, 40 to 80 holes/inch, etc) to a necessary level thereby achieving the necessary surface effects require for apparel, upholstery, bed and bath applications.
In an embodiment, on the drum (D4), by selecting suitable sleeve and fluid jets, various surface effects such as striking off of loose hairs, loose color, embossing, aperturing effects may be created on the composite fabric suitable for apparel, upholstery, bed and bath applications.
In an embodiment, on drum (D4), by adjusting one of the fluid jets, at an angle (example 20 deg to 35 deg) to the drum and fabric surface thereby combing the yarn surfaces very effectively. This arrangement may be used for creating the effects equivalent to pitching or emery finishes on the composite fabric (5) surface suitable for apparel application.
The composite fabric (5) made according to this invention may be further processed using chemicals or heat so as to lock and freeze the entanglement points to a necessary level thereby achieving a balance between elastic and plastic movement.
Thus, according to the principles of this invention, the composite fabric can be made at an affordable cost in the following way.
Tear and Tensile strength of the base fabric (1) can be improved substantially by virtue of realizing the strength of fibers directly from the non-woven web combined with the base fabric (1). The composite fabric (5) can be made isotropic or anisotropic by controlling non-woven web geometry. Therefore, there is no need to use expensive fibers.
Fabric body can be improved, for example, a 11-ounce fabric can be made to feel like 14-ounce fabric. This can be achieved through web geometry and level of entanglement with base fabric (1).
Complete dimensions of the fabric can be retained to as close as possible to the loom/manufacturing stage dimensions with the achievement of best dimensional stability. Functional fibers from the web (110) which are locked into the yarn structures of the base fabric (1) will freeze the yarn positions as they are, resulting into minimal shrinkage potential and best dimensional stability.
Keeping the OE based fabrics, flatness and washdowns of ring yarns based fabrics may be obtained. Also, economical stretches can be developed through this route and flat washdowns can be achieved.
Wherever possible by using heavier functional fiber webs (110) of waste and/or blend of waste and virgin fibers, basic fabric can be made lighter and/or thinner thereby saving overall costs.
Also, there will be a great opportunity for bringing down the raw material cost. The usage of expensive fibers can be curtailed in the conventional fabric process and can be supplemented by proper selection of fibers, web geometry, hydro-entanglement energy and number of passes through the hydro-entanglement process. This is a most economical way.
Conventionally, functions are introduced in the fabric by way of chemical finishes that do not stay long. Expensive functional fibers are blended with regular fibers. And one doesn't have a direct control on fiber position in yarn structure. Accordingly, there will not be a complete realization of benefits of these functional fibers. Also, if the fibers are of different origin, will call for dyeing of both which would be an expensive proposal.
In an embodiment, according to this invention, in a composite fabric, we can place only required quantity of fibers at the right place and realize the complete benefits. Also, in case of backside functional layer, the fibers selected need not be dyed or else one can use predyed fibers and initiate the action. Since these fibers are of only adequate quantity and are properly entrapped into yarn structures, the fibers will stay long enough and offer functions for a substantial long time.
According to the principles of this invention, the applications of the composite fabric may include:
Fibers and additives undoable through conventional processes can be done using the principles of this invention and be made as the integral part of the base fabric (1).
Further, aperturing, embossing tools of this non-woven fabric can be used for enhancing further the base fabric using the principles of this invention. For example, (i) wash and remove Indigo/Sulphur from the selected areas on the fabric and generate various patterns, logos, etc on face side of fabric (ii) Emboss the patterns and generate different look, touch and feel of the fabric (iii) offer pre-washed fabric wherein one can vary the level of wash, uniformity of wash and also generate virtual optics during wash. This can be achieved through proper selection of jet pressures, throughput rates, and different embossing sleeves. If the need be, fabric can be apertured in different patterns using different aperturing sleeves.
However, one can take any fabric, define a function, get right fiber and/or additives hydro-entangle the composites together using right combination of parameters. In the apparel textiles, upholstery, towels and wipes, conventional textile process doesn't need much changes implying easy to get through. We can use all types of staple fibers manmade, natural, etc. Also, one can use powders/very small fibers like wood pulp, paper pulp, etc and find out new applications. This is a 100% hygienic process since it uses water in the form of high pressure jets to bond the composites. Accordingly, products are hygienic.
The fear of pilling or poor abrasion resistance or peeling off of layers does not exist, as there is no 100% non-woven fabric. Fibers from the web (110) are pushed through and are entrapped into yarn structure of the base fabric (1). Also, the right combination of web GSM, Fiber type, web geometry, hydro-entanglement energy levels, entanglement time and number of passes will result into trouble free composite fabric (5).
Various applications of the composite fabric includes durable stain and water repellent fabric using film/membrane and staple fibers, work wear and protective wears, long life chemical finishes using plasma activation technology, semi durable and durable goods.
Thus, various specific embodiments of this invention provide a method and a system for treating a fabric. Further embodiments of this invention provide a method for manufacturing a composite fabric and a composite fabric thereof.
Various modifications of this invention are possible. However, it will be recognized by those skilled in the art that all such modifications have been deemed to be covered by this invention and are within the spirit and scope of the claims appended hereto.
| Number | Date | Country | Kind |
|---|---|---|---|
| 433/MUM/2007 | Mar 2007 | IN | national |
| 598/MUM/2007 | Mar 2007 | IN | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IN2007/000605 | 12/18/2007 | WO | 00 | 2/23/2010 |
