EP2363518A1

EP2363518A1 - Allergy protecting fabric, use and method for its production

Info

Publication number: EP2363518A1
Application number: EP10425054A
Authority: EP
Inventors: Gianfranco Cipriani
Original assignee: Allergosystem Srl
Current assignee: Allergosystem Srl
Priority date: 2010-03-03
Filing date: 2010-03-03
Publication date: 2011-09-07

Abstract

In a fabric (1) comprising a first and a second plurality of yarns (2,3) woven in a weft and warp configuration, the warp is produced with a first yarn (2) comprising filaments formed of a plurality of fibres, having a count below 1.0 den/fibre, the sum of said fibres providing a filament having dtex between 45 and 170 and the weft is produced with a second yarn (3) comprising multi-filament threads having a count between 40 and 80 dtex. Said fabric has anti-allergen barrier properties, in particular against mites, and is used for said purpose.

Description

The present invention concerns a fabric for protection against allergies, the use thereof and a method for its production. More specifically, the invention concerns a fabric for protection against allergies due to mites, dust, mould and similar.
It is known that mites, in the form of their excrement, and dust can be responsible for the onset of allergies in humans; more specifically, research has identified that a particular source of allergens is represented by mattresses and pillows, also due to the time spent in contact with the same. Various types of textile products are known for preventing or reducing contact between users and mites and their allergens; in particular textile products in the form of mattress covers and pillow covers are known.
These textile products are produced by means of two different processes and they have different characteristics; a first type is formed of fabrics (i.e. fabrics with weft and warp) coated with Dicrylan and Teflon on at least one side to prevent the passage of the mites and their excrement. Said products have the drawback of not being very permeable to air and water vapour and therefore causing perspiration during use of the mattresses or pillows. Textile products based on non-woven fabrics obtained by spunbonding or spunlacing, from extrusion of thermoplastic filaments which are then drawn in a current of air and deposited on a movable support to form a non-woven fabric, are also known. The filaments thus obtained are then bonded, preferably by jets of water at high pressure (jetbonding). In the preferred embodiment filaments are used (more precisely monofilaments) in polypropylene 100%.
An example of a textile product of this type is known and is sold for use as a mattress cover or pillow cover for human use. For example, said non-woven fabric is produced by Texbond SpA and marketed under the name Softbond ® or Ultrabond ®.
The use as an anti-mite barrier of microfibre non-woven fabrics obtained from coextrusion of different materials (e.g. polyester and polyamide) positioned side by side to form different segments of one single filament is also known; when subjected to the above-mentioned jets of water at high pressure, the filaments split to give a plurality of sub-filaments which generate an intricate labyrinth structure of microfibres. The structure remains the same even when the gram weights are changed and after any material finishing processes. Preferably polyester and polyamide are used in a ratio 70/30 or 50/50.
EP 1251759 describes the anti-allergy use of said non-woven microfibre fabrics where the initial filament is split for at least 80% into microfibres with dimensions between 0.1 and 0.8 dtex.
An example of a product produced in this way is sold by Freudenberg under the name Evolon ® and by Orsa under the name Micro-Jet Orsa ®. Machines for obtaining these types of filaments and non-woven fabrics are sold for example by Farè SpA (IT) and by Reifenhauser (DE). An example of a process for producing a suitable product is described in US 6815382 and in W02008072278 .
The main drawback of this product is that, despite its filtering capacity, the surface retains large quantities of dirt and allergens.
In fact the main use of these products is the production of cleaning cloths which provide excellent results even without the use of detergent. Moreover, the gram weight, higher than 100 g/m², together with the thickness of 400 µm, gives the product a stiff rough feel.
Both coated fabrics and non-woven fabrics can be used only as mattress covers and pillow covers and are too unpleasant to the touch to be used as sheets, pillowcases or duvet covers. Furthermore, the characteristics of non-woven fabrics as an anti-allergy barrier diminish in the long term with washing and are ultimately lost or drastically reduced.
A new textile product is therefore necessary to combat allergies, in particular caused by mites, which is free from the problems mentioned above.
The object of the present invention is to solve the problems discussed above and provide a textile product with anti-allergic characteristics, i.e. able to act as an effective anti-allergy barrier, in particular as regards allergies caused by mites and dust, said product also being pleasant to the touch, inexpensive and reliable.
Said object is achieved by means of the present invention, which concerns a fabric characterised according to claim 1 and its use according to claim 7 or 8.
According to a preferred embodiment of the invention, the fabric has a gram weight of between 40 and 90 g/m² and preferably between 50 and 70 g/m². The thickness of the fabric is less than 300 µm, preferably less than 200 µm and more preferably around 100 µm.
According to another aspect of the invention, the first yarn comprises 5 to 12 fibres per filament and forms the weft of the fabric; preferably said filament is of the "star" type. A "star" filament is a filament which is formed of a polyamide matrix and a plurality of single fibres, so-called "sub-filaments", generally in polyester or PET, immersed in the matrix. The number of sub-filaments (or fibres) is generally between 6 and 10 and in each single thread there are from 36 to 80 sheaths for a total number of fibres which varies from 216 to 640. The count of the fibres is below 1.0 den/fibre, preferably below 0.4 and more preferably below 0.3 den/fibre.
Yarns of this type can be obtained from the company HYOSUNG (Korea) and are identified as Nylon/PET conjugated yarns, for example under the initials XF in http://www.mipan.com/eng/customer support/pdf/nylon catalogue.pdf. "Star-type" or conjugated N/P yarns can also be obtained from the company Noyfil SpA (Sondrio, Italy) under the commercial name Micralon.
In one embodiment of the invention, the first yarn can also be formed of the type obtained from textured microfibre, for example PES, with a denier per fibre not higher than 1.0, preferably no higher than 0.6 and even more preferably no higher than 0.4. den/fibre Yarns of this type are sold for example by the company Noyfil.
The second yarn is a multifilament thread, preferably in PES, preferably with a count between 45 and 80 dtex and with bright trilobal section. In the preferential embodiment, the number of sub-filaments (or fibres) is at least 36 with a fineness of each single fibre of no higher than 1.3 den/fibre (1.4 dtex/fibre).
Yarns of this type are commercially available and can be obtained for example from the company Noyfil (Andalo Valtellino, Sondrio, Italia) under the name Micrell.
Preferably the first yarn forms the weft of the fabric and the second yarn forms the warp.
In any case, in the fabric according to the invention the filaments of the first yarn are in expanded form, i.e. the single fibres present in the initial filament are grouped together but not cohered. If the fibres are initially cohered and joined to one another, they must be singularised, i.e. separated from one another to increase the volume of the yarn and close the spaces initially present in the fabric.
Preferably, the warp yarns are formed of the multi-fibres filaments (i.e. the second yarn) and the weft yarns are formed of the micro-fibres filaments (i.e. with the first yarn).
The invention furthermore concerns a process for the production of a fabric as defined above, characterised as claimed in claim 9.
Said process is characterised by the fact that it comprises the following phases: prepare a fabric with weft and warp in which at least part of said weft or said warp is produced with a first yarn comprising filaments formed of a plurality of fibres having a count below 1.0 den/fibre preferably below 0.5 den/fibre and more preferably below 0.3 den/fibre, the sum of said fibres providing a yarn having a count between 45 and 170 dtex and in which said warp or weft is produced with a second yarn comprising yarns having a count between 45 and 80 dtex; if necessary, expand the fibres present in said first filament to reduce the spaces between weft and warp; perform any finishing operations.
According to an embodiment of the invention, the yarn is a star-type yarn comprising a polyamide matrix containing a plurality of fibres in PES or PET with a count below 0.4 den and the expansion phase of said fibres is obtained by treatment of the fabric in a basic solution.
According to another embodiment of the invention, the yarn comprises a plurality of fibres with a count below 0.4 den/fibre coextruded together and the expansion phase is performed by thermal/mechanical action on said yarn to separate said fibres.
According to another embodiment of the invention, the filament comprises a plurality of fibres with a count below 0.4 denier/fibre in polyester and in polyamide coextruded together and the expansion phase is performed by mechanical action on said filament to separate said fibres.
The fabric according to the invention has numerous advantages with respect to the known fabrics. Firstly it is able to function as an anti-allergen barrier, in particular against mites and their allergens. Secondly it is much cheaper to produce; furthermore, the fabric of the invention has a much better feel and appearance than those of the known textile products and can therefore be used to produce objects intended for direct contact with the user.
A further advantage is given by the fact that the anti-allergen properties of the fabric according to the invention endure in the long term, also after the fabric has been washed many times, unlike the coated fabrics and non-woven fabrics known in the art.
The invention will now be illustrated in further detail with reference to the accompanying drawing in which:

fig. 1 shows by way of non-limiting illustration a fabric structure according to the invention.

As mentioned above, the fabric 1 according to the invention comprises a first and a second plurality of yarns, 2 and 3, woven in a weft and warp configuration; at least part of said weft or said warp is produced with a first yarn, 2, which is of the type that comprises a multiplicity of filaments in turn formed of a plurality of fibres having a count below 1.0 den/fibre, preferably below 0.4 den/fibre, the sum of said filaments providing a yarn having dtex between 45 and 170.
Vice versa, the remaining part of the fabric, i.e. the warp (if the yarn 2 is used for the weft) or the weft (if the yarn 2 is used for the warp) is produced with a yarn 3 having a count between 45 and 80 dtex; the yarn is multi-fibres with fineness of 1.2 den/fibre.
Suitable fibres are, for example, those mentioned above and produced and marketed by the companies Hyosung (Ulsan, Korea) and Noyfil (Andalo Valtellino, Sondrio, Italy).
In a preferential embodiment, the fibres cohere with one another temporarily and can be processed as if they formed one single element or fibre. Said fibres can be separated by partial breakage or dissolution of the filament 2 to give an expansion of the filament which is transformed into a bundle of fibres, or microfibres, and increases its volume so as to close or substantially reduce the spaces initially present between weft and warp.
The term multi-fibres threads indicates yarns which have a count between 40 and 80 dtex, preferably between 50 and 60 dtex; preferably the fibre is made of smooth polyester, non-loaded and more preferably trilobal to give the end fabric a silky appearance and feel. In the preferential embodiment, the number of fibres is at least 36 per yarn with a fineness of each single fibre no higher than 1.3 den/fibre (1.4 dtex/fibre).
In the preferential embodiment, the multi-filament threads are used for the warp and the multifibre filaments are used for the weft. Preferably the weave is of the plain type, the number of threads per cm is between 55 and 90 and the number of weft threads per cm between 32 and 46.
The gram weight of the fabric is in the range between 40 and 90 g/m², preferably between 50 and 80 g/m² and more preferably between 60 and 70 g/m² - A preferred gram weight is 60 g/m².
In the preferential embodiment of the invention, the weft yarn has a count between 50 and 160 den with 36 to 80 sheaths for a total number of fibres which varies from 216 to 640 and a count not higher than 0.3 den/fibre; the warp yarn has a count between 50 and 60 dtex with number of fibres no less than 36 and with a fineness of each single fibre no higher than 1.3 den/fibre. Alternatively the weft yarn is made of PES textured microfibre , with a den/fibre not higher than 0.4.
In fig. 1 it can be seen that the difference between weft and warp yarns is also reflected in their appearance. The enlarged photograph shows the fabric of the invention in its final configuration; it can be observed that the warp yarns 3 have a plurality of substantially parallel filaments while the weft yarns 2 are formed of an "expanded" or "voluminous" mass of fibres/sub-filaments of small dimensions, or microfibres.
The photograph of fig. 1 also shows a thread 4, of dark colour, which follows a weft yarn; the thread 4 has the function of strengthening the structure and preventing any breakages of the fabric. Threads suitable for said purpose have a count of approximately 120-160 dtex, preferably around 140 dtex, and are preferably used also in the warp to obtain a square effect. The dimensions of the square range from 4 to 8 cm per side.
In variations of the invention, in addition to the thread 4 or in its place are silver threads with bactericidal function and/or carbon threads which function as a barrier to electromagnetic waves.
The process for production of the fabric according to the invention entails initial preparation of the fabric in the manner known in the art. In the preferential embodiment the weave is of the plain type.
In the embodiment that uses a "star-type" yarn for the weft it is necessary to separate the fibres contained in the polyamide sheath. This phase is performed by treatment in a bath of a basic solution, generally with NaOH. Treatments of this type are known in the art for star-type fabrics, i.e. fabrics obtained only from star-type yarns, and require approximately 24 hours to be completed. Analogous treatments can be used also to treat the fabric according to the present invention.
However, to operate more rapidly and, above all, due to the different composition of the fabric of the invention with respect to the known fabrics, the dissolution of the sheath and release from the same of the fibres/microfibres contained in it is performed in conditions very different from the known conditions: a solution of NaOH from 4 to 30 degrees Baumé is used at a temperature between 60 and 140°C for a treatment time between 30 and 60 minutes.
Preferential ranges are solutions with density from 10 to 30 degrees Baumé and bath temperature between 105 and 125 degrees C.
The bath described above is followed by thorough washing with detergents and drying, preferably of the free type.
The dry fabric then undergoes a heat-setting treatment in a hot-air tentering (Rameuse) machine. Hot calendering is then performed on the fabric at a temperature between 160 and 190°C, preferably approximately 180° with a pressure between 50 and 70 tons, preferably 60 tons, and at a speed of between 6 and 20 metres per minute.
As mentioned above, the fabric thus obtained has anti-mite barrier properties. The permeability to the air is between 200 and 300 l/min/m².
Further characteristics of the fabric are the following:
filament density per square decimetre between 100,000 and 250,000 fibres.

Dynamometric strength Elongation % Stitching strength

Kg kg

Warp weft warp weft warp weft

25 60 18 35 30 30

Claims

A fabric (1) comprising a first and a second plurality of yarns (2,3) woven in a weft and warp configuration, characterised in that at least part of said weft or said warp is produced with a first yarn (2) comprising filaments formed of a plurality of fibres, having a count below 1.0 den/fibre, the sum of said fibres providing a filament having dtex between 45 and 170 and in that, vice versa, said warp or weft is produced with a second yarn (3) comprising multi-filament threads having a count between 40 and 80 dtex.
The fabric as claimed in claim 1, wherein said fabric has a gram weight between 40 and 90 g/m².
The fabric as claimed in claim 1 or 2, wherein said plurality of fibres comprises 5 to 12 fibres per filament.
The fabric as claimed in any of the preceding claims, wherein said multifibre filaments are of the type comprising a polyamide matrix conjugated with PES/PET microfibres.
The fabric as claimed in any of the preceding claims, wherein said textile material has a permeability to the air measured with DIN EN ISO 9237 in the range between 150 and 400 l/dm²*min.
The fabric as claimed in any of the preceding claims, wherein the warp yarns are formed of said second yarn and the weft yarns are formed of said first yarn.
The fabric as defined in one or more of the claims from 1 to 6 for use as protection against allergies.
The use of a fabric as defined in one or more of the claims from 1 to 6 as mattress covers, pillow covers, sheets, pillowcases or duvet covers.
A process for the production of a fabric as claimed in any claim 1 to 6, characterised in that it comprises the following steps: prepare a weft and warp fabric in which at least part of said weft or said warp is produced with a first yarn comprising filaments formed of a plurality of fibres having a count below 1.0 den/fibre, the sum of said fibres providing a filament having dtex between 45 and 170 and in which said warp or weft is produced with a second yarn comprising multi-filament threads having a count between 40 and 80 dtex; if necessary expand the fibres present in said first filament to reduce the spaces present between weft and warp; perform any finishing operations.
The process as claimed in claim 9, wherein said filament is a filament comprising a polyamide matrix in which a plurality of said fibres with a count below 1.0 den are present and in which said expansion of said fibres is obtained by treatment of the fabric in a basic solution.
The process as claimed in claim 9, wherein said filament comprises a plurality of fibres with a count below 10 dtex in polyester and in polyamide coextruded together and wherein said expansion phase occurs by thermal/mechanical action on said filament to separate said fibres.
The process as claimed in claim 10, wherein said treatment in basic solution is performed in a solution of NaOH from 4 to 30 degrees Baumé at a temperature between 60 and 140°C.
The process as claimed in claim 12, wherein said fabric is subsequently washed, dried and lastly undergoes a heat-setting treatment in a hot-air tentering machine.
The process as claimed in claim 12 or 13, furthermore comprising a hot calendering phase at a temperature of approximately 180° with a pressure of 60 tons and at a speed ranging from 6 to 20 metres per minute.