Patent Application
20110237146
The present invention relates to a knitted fabric, in particular a knitted fabric that is a piece of clothing which protects the wearer against cutting injuries and has a good wear comfort.
Knitted fabrics of this type, e.g. in the form of a glove, are described in WO 2008/017400. The knitted fabrics described there, in particular gloves, are commonly worn directly on the skin and combine a good cut protection with a high tactility, which represents one aspect of the wear comfort and is particularly desired if the wearer has to deal carefully with small and delicate components. During rougher activities, the wear comfort, which adjusts to the wearer of the knitted fabric, depends to a great extent on the physical exertion to which the wearer is subjected.
If the wearer is subjected to a merely moderate level of physical exertion, during which there is little perspiration, the perspiration generated evaporates already within the sweat ducts of the skin and consequently generates an increased water vapor partial pressure in the microclimate between the skin surface and the inner surface of the knitted fabric; however, no liquid water accrues, so that the wearer does not detect a significant reduction in the wear comfort as long as there is no condensation of the water vapor into water in the microclimate between the skin surface and the inner surface of the knitted fabric.
In contrast, if the wearer is subjected to continuing, strenuous physical exertion, causing a great deal of perspiration, liquid water accrues on the skin surface and this is detrimental to the wear comfort.
Therefore, it is the object of the present invention to provide a knitted fabric that has a cut resistance equally as good as the knitted fabrics described in the prior art, yet increases the wear comfort.
This object is achieved by a knitted fabric I made of
Surprisingly, an inventive knitted fabric I, with an equally good cut resistance, shows a higher wear comfort in the form of a lower water vapor flow resistance in comparison to a comparison knitted fabric that differs from the inventive knitted fabric I only in that the yarns and twisted threads thereof have only the staple fiber component A and no staple fiber component B. The lower the water vapor flow resistance of a material, the higher the ability thereof to allow water vapor to permeate. The ability of a material to allow water vapor to permeate is also designated as the “breathability” of the material. Thus, an inventive knitted fabric I has a higher breathability than the corresponding comparison knitted fabric.
The surprisingly increased breathability of the inventive knitted fabric I leads to the fact that, during only moderate physical exertion of the wearer, the water vapor exiting from the sweat ducts of the skin is more quickly wicked away by the inventive knitted fabric I than by the comparison knitted fabric, so that the water vapor partial pressure in the microclimate between the skin surface and the inner side of the inventive knitted fabric I is lower than when wearing the comparison knitted fabric. Consequently, the inventive knitted fabric I has the effect that the wearer thereof senses a dryer and thus more pleasant feeling on the skin than the wearer of the comparison knitted fabric.
If the wearer is exposed to continuing, strenuous physical exertion, the inventive knitted fabric I can admittedly also not prevent the wearer from perspiring a great deal, so that liquid water accrues on the skin surface. However, the surprisingly increased breathability of the inventive knitted fabric I has the effect that, after the transition from strenuous to moderate physical exertion, the liquid perspiration accrued on the skin is more quickly wicked away by the inventive knitted fabric I than by the comparison knitted fabric, so that the wearer of the inventive knitted fabric I arrives at a state of dry skin surface, i.e. an increased wear comfort, more quickly than the wearer of the comparison knitted fabric.
Thus, the inventive knitted fabric I surprisingly effects an increase in wear comfort at the same cut resistance.
The staple fiber component A of the inventive knitted fabric I comprises aramid staple fibers. Preferably, the staple fiber component A of the inventive knitted fabric I is made of aramid staple fibers.
Within the context of the present invention, the term “aramid staple fibers” means staple fibers which are manufactured by tearing or cutting aramid filament yarns, i.e. filament yarns, the filament forming polymer whereof is an aramid, i.e. an aromatic polyamide, wherein at least 85% of the amide linkages (—CO—NH—) are attached directly to two aromatic rings.
The aramid staple fibers in the inventive knitted fabric I are preferably p-aramid staple fibers, particularly preferably poly(p-phenylene terephthalamide) staple fibers, thus staple fibers that are manufactured from a filament yarn, the filament forming polymer thereof resulting from the mole-for-mole polymerization of p-phenylene diamine and terephthaloyl dichloride. In addition, p-aramid staple fibers are suitable for the inventive knitted fabric I that are manufactured from a filament yarn, the filament-forming polymer whereof being a copolymer which contains, in addition to p-phenylene diamine and terephthaloyl dichloride, minor amounts of other diamines and/or other dicarboxylic acid chlorides embedded in the polymer chain. As a general rule it is understood that, in relation to p-phenylene diamine and terephthaloyl dichloride, the other diamines and/or dicarboxylic acid chlorides can be incorporated in the polymer chain in an amount of up to 10 mole percent.
The length of the aramid staple fibers of staple fiber component A of the inventive knitted fabric I preferably lies in the range from 20 mm to 180 mm, particularly preferably in the range from 30 mm to 120 mm, and more particularly preferably in the range from 30 mm to 100 mm.
The staple fiber component B of the inventive knitted fabric comprises at least one type of seed fibers or staple fibers manufactured by tearing or cutting lyocell fibers enriched with algae or a mixture of at least one type of seed fibers with staple fibers manufactured by tearing or cutting lyocell fibers enriched with algae.
In a preferred embodiment of the inventive knitted fabric I, the at least one type of seed fibers comprises kapok fibers, cotton fibers, akon fibers, or a mixture of two or three of the named seed fibers, in particular a mixture of kapok fibers and cotton fibers, wherein the weight ratio of kapok fibers:cotton fibers lies preferably in the range from 50:50 to 5:95, and particularly preferably in the range from 30:70 to 5:95.
Kapok fibers, which are obtained from the kapok tree, are cellulose hollow fibers with a length distribution that extends from fiber lengths of approximately 15 mm up to fiber lengths of approximately 40 mm.
Cotton fibers are seed hairs from cultivated Gossypium types, wherein the fibers have a length distribution, and the length distribution extends from fiber lengths of approximately 10 mm up to fiber lengths of approximately 55 mm.
Akon fibers are seed hairs from Asclepiadaceae and Apocynaceae, wherein the fibers have a length distribution, and the length distribution extends from fiber lengths of approximately 10 mm up to fiber lengths of approximately 30 mm, less often up to fiber lengths of approximately 40 mm as well.
In one embodiment, the inventive knitted fabric I comprises in the staple fiber component B staple fibers manufactured by tearing or cutting of lyocell fibers enriched with algae. Staple fibers of this type can be obtained under the trade name Seacell®, from SeaCell GmbH, Rudolstadt, Germany.
Lyocell fibers are cellulose synthetic fibers, that are manufactured in that cellulose dissolved in an organic solvent is regenerated in fiber form (see MAN-MADE FIBER YEAR BOOK, September 1997, Fiber Tables according to P.-A. KOCH, “Lyocell Fibers”, pages 41-47). The porous structure of the Seacell® staple fibers contributes in the inventive knitted fabric I to the breathability thereof and promotes the release of eudermic algae constituents contained in the Seacell® staple fibers to the skin, e.g. mineral salts like calcium- and magnesium salts, and vitamins like vitamin E, so that an inventive knitted fabric I comprising Seacell® staple fibers exerts a skin nourishing and skin curative effect, by which means a positive effect is achieved on skin diseases such as psoriasis and neurodermatitis. Further, the large degree of softness inherent in the Seacell® staple fibers contributes such that an inventive knitted fabric I comprising Seacell® staple fibers imparts a very pleasant feeling on the skin for the wearer. Consequently, an inventive knitted fabric I that comprises Seacell® staple fibers, shows a high degree of wear comfort.
The staple fibers manufactured by tearing or cutting lyocell fibers enriched with algae (Seacell® staple fibers), used in an embodiment of the inventive knitted fabric I, have preferably a length in the range from 20 mm to 180 mm, particularly preferably in the range from 30 mm to 120 mm, and more particularly preferably in the range from 30 mm to 100 mm.
In a preferred embodiment of the inventive knitted fabric I, the mixture of at least one type of seed fibers with the staple fibers manufactured by tearing or cutting lyocell fibers enriched with algae comprises a mixture of cotton fibers with staple fibers manufactured by tearing or cutting lyocell fibers enriched with algae.
In a further preferred embodiment of the inventive knitted fabric I, the weight ratio in the mixture of cotton fibers with staple fibers manufactured by tearing or cutting lyocell fibers enriched with algae lies in the range from 5:95 to 95:5, and particularly preferably in the range from 20:80 to 80:20.
The inventive knitted fabric I contains the staple fiber component A and the staple fiber component B in a weight ratio of A:B that lies preferably in the range from 99:1 to 50:50, more preferably in the range from 97:3 to 60:40, and more particularly preferably in the range from 95:5 to 70:30. In this case, the aramid staple fibers of the staple fiber component A can consist of 100 wt. % of newly manufactured aramid staple fibers. Alternatively, the aramid staple fibers of the staple fiber component A can consist of 100 wt. % of recycled aramid staple fibers. Further, the aramid staple fibers of the staple fiber component A can consist of any mixture of newly manufactured and recycled aramid staple fibers.
In the inventive knitted fabric I, the twisted thread ZAB is manufactured from at least two of the mixed staple fiber yarns AB, wherein each of the mixed staple fiber yarns AB is manufactured from a homogeneous mixture of A and B. In this case, the expression “homogeneous mixture” means that essentially in each volume element of the mixture of A and B—and consequently also essentially in each volume element of the mixed staple fiber yarn AB manufactured from the homogeneous mixture—the prescribed mixture ratio of A:B is present.
In a preferred embodiment of the inventive knitted fabric I, the mixed staple fiber yarn AB has a linear density in the range from 10 tex to 1000 tex, particularly preferably in the range from 12 to 500 tex, and more particularly preferably in the range from 14 to 100 tex.
Further, in an embodiment of the inventive knitted fabric I, preferably 2 to 10 and particularly preferably 2 to 8 of the mixed staple fiber yarns AB are twisted to form a twisted thread ZAB.
Further, in an embodiment of the inventive knitted fabric I, preferably 1 to 10 and particularly preferably 1 to 8 of the twisted threads ZAB are processed into the inventive knitted fabric I.
In a further preferred embodiment of the inventive knitted fabric I, the knitted fabric I is knitted at a needle gauge, gg, wherein the needle gauge lies preferably in the range from 5 gg to 18 gg, and particularly preferably in the range from 7 gg to 18 gg.
In a further preferred embodiment of the inventive knitted fabric I, the knitted fabric I is knitted with a mesh density in courses, MiR, wherein the MiR preferably lies in the range from 2 to 15 and particularly preferably in the range from 3 to 12.
In a further preferred embodiment of the inventive knitted fabric I, the knitted fabric I is knitted at a mesh density in wales, MiS, wherein the MiS preferably lies in the range from 2 to 15 and particularly preferably in the range from 3 to 12.
The advantageous combination of cut resistance and wear comfort in the inventive knitted fabric I is noticeable in every type of clothing in which the inventive knitted fabric I is worn against the body. Preferably, the inventive knitted fabric I is an article of clothing that is formed as a glove, protective sleeve, hood, or shirt.
The underlying object of the present invention is further achieved by a knitted fabric II made of
Surprisingly, an inventive knitted fabric II, with an equally good cut resistance, shows a higher wear comfort in the form of a lower water vapor flow resistance in comparison to a comparison knitted fabric which differs from the inventive knitted fabric II only in that the yarns and twisted threads thereof only have the staple fiber component A and no staple fiber component B. In this case, the terms “aramid staple fibers”, “seed fibers”, and “staple fibers manufactured by tearing or cutting lyocell fibers enriched with algae” have the same meaning as was already explained in the description of the inventive knitted fabric I.
Within the context of the present invention, the term “polyolefin staple fibers” means staple fibers that are manufactured by tearing or cutting polyolefin filament yarns, i.e. filament yarns, the filament-forming polymer whereof is a polyolefin, preferably a polypropylene and particularly preferably a polyethylene. Consequently, the polyolefin staple fibers in the inventive knitted fabric II are preferably polypropylene staple fibers and particularly preferably polyethylene staple fibers. Thereby, in the context of the present invention, polyethylene is understood to be a substantially linear polyethylene material that has a molecular weight preferably greater than one million and can include minor amounts of chain branchings or of comonomers, whereby a minor amount is understood to mean that for every 100 carbon atoms in the primary chain, no more than 5 chain branchings or comonomers are present. The linear polyethylene material can additionally contain up to 50 wt. % of one or more polymer additives, such as alkene-1 polymers, in particular, low-pressure polyethylene and the like, or low-molecular additives such as antioxidants, UV absorbers, dyes and the like, which are usually incorporated. A polyethylene material of this type is known under the designation “extended chain polyethylene” (ECPE). Within the context of the present invention, polypropylene is understood to be a substantially linear polypropylene material having a molecular weight of preferably more than one million.
The length of the polyolefin staple fibers of staple fiber component A of the inventive knitted fabric II preferably lies in the range from 20 mm to 180 mm, particularly preferably in the range from 30 mm to 120 mm, and more particularly preferably in the range from 30 mm to 100 mm.
In an embodiment of the inventive knitted fabric II, the staple fiber component A comprises aramid staple fibers and polyolefin staple fibers, wherein the weight ratio of aramid staple fibers:polyolefin staple fibers lies in the range from 95:5 to 5:95, particularly preferably in the range from 80:20 to 20:80.
In a preferred embodiment of the inventive knitted fabric, the polyolefin staple fibers are polyethylene staple fibers.
In an embodiment of the inventive knitted fabric II, the pure staple fiber yarn RA preferably has a linear density in the range from 10 tex to 1000 tex, particularly preferably in the range from 12 to 500 tex, and more particularly preferably in the range from 14 to 100 tex.
Further, in an embodiment of the inventive knitted fabric II, the pure staple fiber yarn RB preferably has a linear density in the range from 10 tex to 1000 tex, particularly preferably in the range from 12 to 500 tex, and more particularly preferably in the range from 14 to 100 tex.
In addition, in an embodiment of the inventive knitted fabric II, preferably 2 to 10 and particularly preferably 2 to 8 of the pure staple fiber yarns RA are twisted to form a twisted thread ZA.
Further, in an embodiment of the inventive knitted fabric II, preferably 2 to 10 and particularly preferably 2 to 8 of the pure staple fiber yarns RB are twisted to form a twisted thread ZB.
In addition, in an embodiment, the inventive knitted fabric II is manufactured by plaiting preferably 1 to 8 of the twisted threads ZA with preferably 1 to 8 of the twisted threads ZB, wherein it is particularly preferred that the knitted fabric II is manufactured by plaiting 1 to 6 of the twisted threads ZA with preferably 1 to 6 of the twisted threads ZB.
In a further preferred embodiment, the inventive knitted fabric II is knitted at a needle gauge, gg, wherein gg lies preferably in the range from 5 to 18, and particularly preferably in the range from 7 to 15.
In a further preferred embodiment, the inventive knitted fabric II is knitted with a mesh density in courses, MiR, wherein the MiR preferably lies in the range from 2 to 15 and particularly preferably in the range from 3 to 12.
In a further preferred embodiment, the inventive knitted fabric II is knitted with a mesh density in wales, MiS, wherein the MiS preferably lies in the range from 2 to 15 and particularly preferably in the range from 3 to 12.
If the inventive knitted fabric II is varied in that the pure staple fiber yarn RA is replaced by a pure filament yarn RA′, there results in an otherwise identical structure likewise a knitted fabric II′, manufactured by plaiting, having an attractive combination of cut resistance, abrasion resistance, and wear comfort.
The advantageous combination of cut resistance and wear comfort in the inventive knitted fabric II is noticeable in every type of clothing in which the inventive knitted fabric II is worn against the body. Preferably, the inventive knitted fabric II is an article of clothing that is formed as a glove, protective sleeve, hood, or shirt.
The invention will be described in more detail using the following examples:
40 mm long staple fibers made of poly-p-phenylene terephthalamide (Twaron 1070 from Teijin Aramid GmbH) are used as staple fiber component A. Kapok fibers with a length distribution that extends from fiber lengths of approximately 15 mm up to fiber lengths of approximately 40 mm are used as staple fiber component B. A homogeneous staple fiber mixture is produced from 90 wt. % of component A and 10 wt. % of component B. A mixed staple fiber yarn AB with a linear density of Nm 28, i.e. 36 tex is manufactured from the homogeneous staple fiber mixture. Two of these mixed staple fiber yarns AB are twisted to form a twisted thread ZAB. Four of these twisted threads ZAB are fed parallel into a knitting machine and knitted into a glove with a needle gauge of 7 gg, a mesh density in courses, MiR, of 3.5, and a mesh density in wales, MiS, of 3.5.
Three inventive gloves, 1a, 1b, and 1c, are knitted in this way. The cut resistance N is measured on the inventive gloves 1a, 1b, and 1c according to ISO 13997 (August 1999).
40 mm long staple fibers made of poly-p-phenylene terephthalamide (Twaron 1070 from Teijin Aramid GmbH) are used as staple fiber component A. Kapok fibers with a length distribution that extends from fiber lengths of approximately 15 mm up to fiber lengths of approximately 40 mm are used as staple fiber component B. A homogeneous staple fiber mixture is produced from 90 wt. % of component A and 10 wt. % of component B. A mixed staple fiber yarn AB with a linear density of Nm 28, i.e. 36 tex is manufactured from the homogeneous staple fiber mixture. Two of these mixed staple fiber yarns AB are twisted to form a twisted thread ZAB. One of these twisted threads ZAB is fed into a knitting machine and knitted into a glove with a needle gauge of 13 gg, a mesh density in courses, MiR, of 6.0, and a mesh density in wales, MiS, of 7.5.
Three inventive gloves, 2a, 2b, and 2c, are knitted in this way. The cut resistance N is measured on the inventive gloves 2a, 2b, and 2c according to ISO 13997 (August 1999).
Only staple fiber component A is used, i.e. 40 mm long staple fibers made of poly-p-phenylene terephthalamide (Twaron 1070 from Teijin Aramid GmbH). A staple fiber yarn with a linear density of Nm 28, i.e. 36 tex, is manufactured from 100 wt % of component A. Two of these staple fiber yarns are twisted to form a twisted thread. Four of these twisted threads are fed parallel into a knitting machine and knitted into a glove with a needle gauge of 7 gg, a mesh density in courses, MiR, of 3.5, and a mesh density in wales, MiS, of 3.5.
Three comparison gloves, V1a, V1b, and V1c, are knitted in this way. The cut resistance N is measured on the comparison gloves V1a, V1b, and V1c according to ISO 13997 (August 1999).
Only staple fiber component A is used, i.e. 40 mm long staple fibers made of poly-p-phenylene terephthalamide (Twaron 1070 from Teijin Aramid GmbH). A staple fiber yarn with a linear density of Nm 28, i.e. 36 tex, is manufactured from 100 wt % of component A. Two of these staple fiber yarns are twisted to form a twisted thread. This twisted thread is fed into a knitting machine and knitted into a glove with a needle gauge of 13 gg, a mesh density in courses, MiR, of 6.0, and a mesh density in wales, MiS, of 8.0.
Three comparison gloves, V2a, V2b, and V2c, were knitted in this way. The cut resistance N is measured on the comparison gloves V2a, V2b, and V2c according to ISO 13997 (August 1999).
The results are summarized in Table 1.
The comparison of the inventive gloves 1a-c with the comparison gloves V1a-c shows that the inventive gloves, despite the proportion of 10 wt. % of kapok fibers, have, with the same mass per unit area, a cut resistance N that is equally as good as that of the comparison gloves V1a-c.
The comparison of the inventive gloves 2a-c with the comparison gloves V2a-c shows that the inventive gloves, despite the proportion of 10 wt. % of kapok fibers and despite a somewhat lower mass per unit area, have a cut resistance N that is indeed somewhat better than that of the comparison gloves V2a-c.
A further inventive glove 1d is manufactured using the same conditions as for the gloves 1a-c. According to DIN EN 31 092 (February 1994) or ISO 11092 (15 Oct. 1993), the water vapor flow resistance Ret is measured on the inventive glove 1d. According to the cited standards, Ret means the water vapor partial pressure difference between the two surfaces of the glove, i.e. between the inner and outer sides of the glove, divided by the evaporation heat flow per unit area that results along the water vapor partial pressure gradient.
A further comparison glove V1d is manufactured using the same conditions as for the comparison gloves V1a-c. According to DIN EN 31 092 (February 1994) or ISO 11092 (15 Oct. 1993), the water vapor flow resistance Ret is measured on the comparison glove V1d.
The results of the Ret measurements are presented in Table 2.
The comparison of the inventive glove 1d with the comparison glove V1d shows that the water vapor flow resistance Ret of the inventive glove 1d is 21% lower than the water vapor flow resistance Ret of the comparison glove V1d. Consequently, the breathability of the inventive glove 1d is 26% greater than the breathability of the comparison glove V1d.
Thus, under the conditions of DIN EN 31 092 (February 1994) or ISO 11092 (15 Oct. 1993), which simulate moderate physical exertion, the inventive glove 1d shows a higher wear comfort than the comparison glove V1d at the same cut resistance.
In wear tests without physical exertion of the wearer, the inventive glove 1d also shows a wear comfort that is described by the wearer as more comfortable than the wear comfort of the comparison glove V1d.
| Number | Date | Country | Kind |
|---|---|---|---|
| 08171183.0 | Dec 2008 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2009/066534 | 12/7/2009 | WO | 00 | 6/8/2011 |
