Patent Application
20130095718
The present invention concerns a non-woven fabric material, in particular for making clothing such as T-shirts, shirts, overalls and suchlike, for example but not restrictively low cost and/or disposable. The non-woven fabric material according to the present invention has properties of wearability and elasticity comparable to those of a fabric with a weft-knit structure.
It is known to manufacture a fabric with a weft-knit structure, obtained with weft-knitting, commonly used in the clothing field and which has good properties of wearability, comfort and elasticity.
Articles of clothing manufactured in a known manner with said weft-knit fabric, also due to the cost, are not normally used to produce disposable articles, or articles with a limited or temporary use, and which, in the course of use, must be washed repeatedly, which has a considerable environmental impact. Manufacturing low cost articles of clothing, possibly disposable, is therefore desirable, also in terms of environmental friendliness.
One purpose of the present invention is to manufacture a non-woven fabric material which has mechanical and thermal characteristics comparable to a weft-knit fabric, so as to guarantee on the one hand that it is economical, and on the other hand that it is comfortable and wearable.
Another purpose of the present invention is to manufacture a non-woven fabric material that is more environmentally friendly compared with traditional fabrics with a weft-knit structure.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.
Unless otherwise defined, all the technical and scientific terms used here and hereafter have the same meaning as commonly understood by a person with ordinary experience in the field of the art to which the present invention belongs.
Even if methods and materials similar or equivalent to those described here can be used in practice and in the trials of the present invention, the methods and materials are described hereafter as an example. In the event of conflict, the present application shall prevail, including its definitions. The materials, methods and examples have a purely illustrative purpose and shall not be understood restrictively.
The word “comprise” and variants of the word such as “comprises” and “comprising” are used here to indicate the inclusion of a clearly expressed whole or clearly expressed wholes but not the exclusion of any other whole or any other wholes, unless in the context or in use an exclusive interpretation of the word is required.
The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.
In accordance with the above purposes, a non-woven fabric material according to the present invention is used to make articles of clothing. The non-woven fabric material of the present invention comprises a plurality of thin layers, superimposed and interlaced with each other, advantageously cross-disposed.
Each layer is formed by carded fibers and, according to the present invention, the carded fibers comprise at least 15% in weight, of the total of fibers present, of self-gathering, or self-crimping, fibers. Each self-gathering fiber develops in a main direction of development and is formed by two or more polymers that define corresponding two or more regions joined and adjacent to each other in the direction of development of the self-gathering fiber.
The non-woven fabric material according to the present invention has mechanical and thermal characteristics that are comparable to a weft-knit fabric, so as to guarantee good comfort and wearability.
In one form of embodiment, the non-woven fabric material comprises further fibers, different from the self-gathering fibers, in a mixture with the self-gathering fibers.
In another form of embodiment, the further fibers comprise biodegradable fibers of a natural origin and/or synthetic origin.
According to a variant, the biodegradable fibers of synthetic origin are fibers made of thermoplastic aliphatic polyesters of polylactide and/or viscose fibers.
According to one form of embodiment, the self-gathering fibers represent at least 20% in weight of the total of fibers present, preferably at least 25% in weight, even more preferably at least 30% in weight.
In a specific form of embodiment, the self-gathering fibers represent 100% in weight of the total of fibers present.
According to one form of embodiment, the carded fibers used, both the self-gathering ones and also the other non self-gathering ones, have an average length comprised between about 20 mm and about 110 mm, preferably between about 25 mm and about 105 mm, more preferably between about 30 mm and about 100 mm.
In some forms of embodiment, the carded fibers used, both the self-gathering ones and also the other non self-gathering ones, have a diameter comprised between about 0.7 and about 4 dTex, preferably between about 0.8 and 3.5 dTex, more preferably between about 0.9 and about 3 dTex.
According to some forms of embodiment, said polymers are biodegradable polymers.
According to some variant forms of embodiment, the polymers are chosen from the thermoplastic aliphatic polyesters of polylactide (PLA).
According to other variant forms of embodiment, the polymers are chosen from among the group comprising polytrimethylene terephthalate (PTT) and polyethylene terephthalate (PET).
According to some forms of embodiment, the thin layers are cross-disposed each other.
The non-woven fabric material according to the present invention is less heavy and voluminous compared with a standard fabric with a weft-knit structure.
The non-woven fabric material according to the present invention also has suitable values of heat resistance and permeability to water vapor, guaranteeing the necessary transpirability and hence good comfort.
The non-woven fabric material according to the present invention has mechanical characteristics comparable to a weft-knit “fabric”. In particular the non-woven fabric material according to the present invention has elastic properties along both working axes, both in machine direction (MD), and transverse (CD, or Cross Direction); it also has an adequate drapery effect and hangs well. An article of clothing made with the non-woven fabric material according to the present invention therefore has good wearability.
In the form of embodiment with cross-disposed thin layers, the non-woven fabric material according to the present invention also has an adequate isotropicity of the mechanical properties in both directions, MD and CD.
The present invention also concerns an article of clothing, or similar or comparable article or product, made with a non-woven fabric material as described above.
It also comes within the spirit of the present invention to provide a method to manufacture a non-woven fabric material, which provides to make available a plurality of thin layers formed by carded fibers which are prepared comprising at least 20% in weight, of the total of fibers present, of self-gathering fibers, each self-gathering fiber developing in a main direction of development and being formed by two or more polymers that define corresponding two or more regions joined and adjacent to each other in the direction of development of the self-gathering fiber. The method also provides to superimpose and interlace said thin layers between them, advantageously cross-disposed, in order to obtain a mat of non-woven fabric material.
In a variant form, the method provides to subject the mat obtained to one or more heat treatments in the oven, with temperatures comprised between about 80° C. and about 140° C., preferably between about 85° C. and about 135° C., more preferably between about 95° C. and about 125° C. The duration of the heat treatment is comprised between about 1 minute and about 12 minutes, preferably between about 2 minutes and about 10 minutes, more preferably between about 4 minutes and about 9 minutes.
Thanks to the economy of the method according to the present invention compared with weft-knitting, the non-woven fabric material obtainable with the present invention is more economical and can be used to make articles of clothing such as for example T-shirts, shirts, overalls or suchlike, at low cost or disposable. In this way it is possible to considerably reduce the time the article of clothing is used and hence the environmental impact connected to the number of washes.
Thanks to the use, according to an advantageous variant, of biodegradable fibers, the non-woven fabric material according to the present invention is environmentally friendly, even in applications in disposable articles of clothing.
A non-woven fabric material according to the present invention comprises a plurality of thin layers, superimposed and constrained, bonded or interlaced with each other.
In one form of embodiment, the thin layers of fibers are bonded with each other by hydro-needlepunching, that is, by high pressure jets of water.
Alternatively, the thin layers can be interlaced by mechanical needlepunching or chemical constraint.
Hydro-needlepunching allows higher working speeds compared to mechanical techniques and also allows to obtain products with more regular surfaces. Moreover, this technique avoids producing visible holes. In the case where thermoformable fibers are used, the layers can be bonded by blowing in hot air and/or thermobonding.
Each layer comprises carded fibers and, according to the present invention, a determinate amount of said carded fibers is formed by self-gathering, or self-crimping, fibers. Each self-gathering fiber extends in a main direction of development.
The self-gathering fibers are formed by two or more polymers, which form in a single fiber two or more regions joined and adjacent to each other in the direction of the aforementioned main direction of development, that is, in a side-by-side disposition.
In one form of embodiment, the self-gathering fibers are bi-component, of the side-by-side type.
In particular, the self-gathering fibers have a three-dimensional gathered structure, regular or irregular, which achieves in the individual fiber a capacity for elastic extension. In this case, the gathered structure is helical or spiral.
The gathering of the fibers is determined by the different mechanical and thermal behavior of the two polymers that form the longitudinal portions of the fiber, and in particular is connected to differences in terms of shrinkage, force of shrinkage and elasticity modulus.
The components that form the portions of the self-gathering fibers may be different polymers, provided that they are coordinated and compatible, at least in terms of adhesion, or they may be the same polymer, with differences in terms of orientation, crystallinity or relative viscosity such as to ensure the desired differences in terms of shrinkage, force of shrinkage and elasticity modulus.
In one form of embodiment, the self-gathering fibers of the non-woven fabric material according to the present invention are at least 20% in weight of the total of fibers present, preferably 25% in weight, more preferably at least 30% in weight.
According to a particular form of embodiment, the fibers present in the non-woven fabric material are all self-gathering fibers.
According to an alternative form of embodiment, the non-woven fabric material comprises a mixture of self-gathering fibers with further fibers that are not self-gathering, or not self-crimping.
The components of the self-gathering fibers may also be biodegradable, such as thermoplastic aliphatic polyesters of polylactide or polylactic acid (PLA), or non-biodegradable, in which case it is possible to use for example PA6/PA66, PET/PBT, PE/PP or other pairs of polymers and copolymers, such as for example PET/co-PET.
In one form of embodiment, the non-biodegradable components of the self-gathering fibers are polytrimethylene terephthalate (PTT) and/or polyethylene terephthalate (PET).
In one form of embodiment, the further fibers comprise biodegradable fibers of natural or synthetic origin, such as cotton, wool, linen or bamboo fibers.
In other forms of embodiment, as biodegradable fibers of synthetic origin for the further fibers it is possible to use fibers of thermoplastic aliphatic polyesters of polylactide or polylactic acid (PLA) and/or fibers of viscose or rayon, regenerated cellulose, for example fibers marketed with the trademarks Tencel® or Modal®. In some forms of embodiment, the further fibers can be a mixture of biodegradable fibers of natural and synthetic origin.
In some forms of embodiment mixtures of fibers are provided, of different biodegradable polymers of synthetic origin.
According to one form of embodiment, the non-woven fabric material comprises only biodegradable fibers, both with regard to the self-gathering fibers and to the further fibers.
According to one form of embodiment, the thin layers of carded fibers of the non-woven fabric material are disposed in a structure with cross thin layers, with an angle of stagger between the layers such as to give a CD to MD ratio equal to about 1. This cross-disposition obtains in the non-woven fabric material a high degree of isotropicity in terms of mechanical properties in the machine direction and cross direction.
According to one form of embodiment, the non-woven fabric material may comprise one or more silicon-based softening agents, for example comprising aminosiloxanes, applied on the already formed non-woven fabric material.
According to one form of embodiment, the non-woven fabric material of the present invention may include micro-holes.
A method for the production of non-woven fabric material according to the present invention provides that the self-gathering fibers and the further fibers (in the form of staples) are subjected to an opening step. The open fibers are then mixed together in the desired proportions. The mixed fibers are then subjected to carding and then sent to a crosslapper to form the layers. The mat obtained has a structure with interlaced cross-disposed layers, with a CD to MD ratio of about 1, and is then subjected to hydrobonding or hydro-needlepunching. After a first pass in the oven with a drying function to remove the residual water, the mat is subjected to a damp finishing treatment and a softening agent applied.
According to one form of embodiment, the non-woven fabric material with the thin layers already subjected to bonding, may be subjected to one or more heat treatments in the oven, with temperatures comprised between about 80° C. and about 140° C., preferably between about 85° C. and about 135° C., more preferably between about 90° C. and about 130° C., still more preferably between about 95° C. and about 125° C. The duration of the heat treatment is comprised between about 1 minute and about 12 minutes, preferably between about 2 minutes and about 10 minutes, more preferably between about 4 minutes and about 9 minutes. The processing parameters as above are chosen carefully according to the type and properties of the fibers selected. The heat treatments allow to increase the degree of crimping of the self-gathering fibers and hence to increase the elastic stretching properties of the fibers.
In this case, the mat obtained as described above is then subjected to a second heat treatment, with drying in a ventilated oven at 130° C. for about 9 minutes.
It is clear that modifications and/or additions of parts may be made to the non-woven fabric material as described heretofore, without departing from the field and scope of the present invention.
It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of non-woven fabric material, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.
