Patent Application
20090275253
The present invention relates to a staple fiber yarn, a textile fabric comprising the staple fiber yarn and articles comprising the textile fabric.
WO 97/25464 discloses a staple fiber yarn containing para-aramid staple fibers, having in each case a linear density that lies within the range of 3 to 6 dtex. WO 97/25464 teaches that the cut resistance of an article manufactured from such a yarn, e.g. a glove, can be increased by increasing the linear density of the staple fibers forming the yarn, whereby cut resistance means the force that is necessary to cut through the article, in which the length of the cut measures 25 millimeters. In addition, WO 97/25464 teaches that a staple fiber yarn with a linear density of the staple fibers higher than approx. 6 dtex leads to fabrics that indeed have a very good cut resistance; however, they are neither aesthetically acceptable nor do they offer a suitable wear comfort. Finally, WO 97/25464 teaches that a staple fiber yarn with a linear density of the staple fibers less than approx. 3 dtex leads to fabrics that indeed have a good wear comfort; however, their cut resistance constantly decreases the more the linear density of the staple fibers drops below 3 dtex. Thus, WO 97/25464 teaches that the increase in cut resistance can only be realized with a loss in aesthetic acceptance and wear comfort, while an increase in wear comfort and an improvement in aesthetic acceptance is only obtainable with a loss in cut resistance.
Therefore, the object of the present invention is to provide a staple fiber yarn that facilitates the manufacture of a textile fabric with a high cut resistance and simultaneously with a high wear comfort.
The object of the invention is achieved through a staple fiber yarn comprising a staple fiber blend, containing staple fibers A and staple fibers B, and additional staple fibers as necessary, whereby the staple fibers A as well as the staple fibers B consist of polymers that are selected from the groups of aramids, polyolefins, polybenzoxazoles and polybenzthiazoles, the staple fibers A having a linear density T(A) and the staple fibers B having a linear density T(B), and the linear density ratio of T(B):T(A) lying within the range from 1.5:1 to 8.8:1.
A textile fabric containing the staple fiber yarn according to the invention, and an article comprising this textile fabric, e.g. a glove, show a cut resistance that is at least the same as, if not indeed higher than the cut resistance of a textile fabric manufactured in the same manner from one staple fiber yarn, which contains exclusively staple fibers with a higher linear density T(B).
This is surprising, because one would expect, in light of the teaching given by WO 97/25464, that replacing the staple fibers having a higher linear density with staple fibers having a lower linear density would lead to a loss of cut resistance. Therefore, it is already surprising that the cut resistance does not decline due to the substitution just described. It is even more surprising that the cut resistance can actually be increased due to the aforesaid substitution.
In addition, in light of the teaching given in WO 97/25464, according to which a textile fabric manufactured using yarns from staple fibers with a linear density lower than approx. 3 dtex has a low cut resistance, it has to be surprising that the staple fiber yarn according to the invention comprises to a high degree cut-resistant embodiments that, measured according to DIN EN 388, e.g., are to be classified in cut resistance class 3, and for which the staple fiber linear density T(A) as well as the staple fiber linear density T(B) clearly lie below 3 dtex, so that textile fabrics manufactured from such yarns not only show a high cut resistance, but are also distinguished by a high wear comfort and an appealing appearance.
The staple fiber yarn according to the invention contains staple fibers A and B, whereby the staple fibers A as well as the staple fibers B consist of polymers that are selected from the groups of aramids, polyolefins, polybenzoxazoles and polybenzthiazoles.
Within the context of the present invention, “aramids” means aromatic polyamides, wherein at least 85% of the amide linkages (—CO—NH—) are attached directly to two aromatic rings. An aromatic polyamide particularly preferred for the present invention is polyparaphenylene terephthalamide, a homopolymer resulting from the mole-for-mole polymerization of paraphenylene diamine and terephthaloyl dichloride. In addition, copolymers are suitable as aromatic polyamides for the present invention, which copolymers contain, in addition to paraphenylene diamine and terephthaloyl dichloride, minor amounts of other diamines and/or other dicarboxylic acids embedded in the polymer chain. As a general rule it is understood that, in relation to paraphenylene diamine and terephthaloyl dichloride, the other diamines and/or other dicarboxylic acids can be incorporated in the polymer chain at an amount of up to 10 mole percent.
Within the context of the present invention, “polyolefins” means polyethylene or polypropylene.
Thereby, “polyethylene” is understood to be an essentially linear polyethylene material, which has a molecular weight preferably greater than one million and can include minor amounts of chain branchings or of comonomers, whereby “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, e.g. alkene-1 polymers, in particular, low-pressure polyethylene, low-pressure polypropylene 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 an essentially linear polypropylene, having a molecular weight of preferably more than one million.
Within the context of the present invention, “polybenzoxazoles” and “polybenzthiazoles” are understood to be polymers having the structural units presented in the following, whereby the aromatic groups attached to the nitrogen are preferably carbocyclic, as shown in the structural units. However, said groups can also be heterocyclic. In addition, the aromatic groups attached to the nitrogen are preferably six-membered rings, as shown in the structural units. However, said groups can also be formed as fused or unfused polycyclic systems.
The statement that the staple fibers A as well as the staple fibers B consist of polymers that are selected from the groups of aramids, polyolefins, polybenzoxazoles and polybenzthiazoles means, within the context of the present invention, that all combinations possible through said selection of the polymers mentioned for the staple fibers A and B are comprised.
In a preferred embodiment of the staple fiber yarn according to the invention, the staple fibers A and the staple fibers B are each selected from only one of the groups. This comprises embodiments, in which the staple fibers A are selected either from the group of aramids or from the group of polyolefins or from the group of polybenzoxazoles or from the group of polybenzthiazoles, and the staple fibers B are selected either from the group of aramids or from the group of polyolefins or from the group of polybenzoxazoles or from the group of polybenzthiazoles.
In a more preferred embodiment of the staple fiber yarn according to the invention, the staple fibers A and the staple fibers B are selected from the same group. This comprises embodiments, in which the staple fibers A and the staple fibers B are selected either from the group of aramids or from the group of polyolefins or from the group of polybenzoxazoles or from the group of polybenzthiazoles.
In an especially preferred embodiment of the staple fiber yarn according to the invention, the staple fibers A and the staple fibers B are selected from the same group of aramids, preferably from the para-aramids, whereby within the last-mentioned embodiment, polyparaphenylene terephthalamide is particularly preferred.
The staple fiber yarn according to the invention contains in a preferred embodiment the staple fibers A and B in an at least approx. homogenous blend. This means, within the context of the present invention, that in each volume unit of the staple fiber yarn according to the invention, the weight ratio A:B of the staple fibers A and B specified is at least approx. the same during the manufacture of the yarn, so that in this preferred embodiment, the staple fiber yarn according to the invention is at least approx. free from any core-sheath structure. It is especially preferred that the staple fiber yarn according to the invention contains the staple fibers A and B in a homogenous blend, so that in this especially preferred embodiment the staple fiber yarn according to the invention is free from any core-sheath structure.
In the staple fiber yarn according to the invention, the linear density ratio T(B):T(A) lies in the range from 1.5:1 to 8.8:1. At a linear density ratio less than 1.5:1, the advantageous effects of the yarn are not brought to bear. At a linear density ratio greater than 8.8:1, the wear comfort of an article manufactured from such a yarn, e.g. a glove, leaves much to be desired.
At a linear density ratio T(B):T(A) according to the invention in the range from 1.6:1 to 4.4:1 and in particular in the range from 1.7:1 to 3.2:1, the advantageous effects initially described appear particularly clearly.
In the staple fiber yarn according to the invention, the weight ratio of staple fibers A to staple fibers B can be set within a broad range, e.g. in the range from 90:10 to 10:90. However, at a weight ratio of staple fibers A to staple fibers B from 80:20 to 20:80; in particular at a weight ratio of staple fibers A to staple fibers B from 75:25 to 25:75; and to a still greater degree at a weight ratio of staple fibers A to staple fibers B from 70:30 to 30:70, the advantageous effects initially described appear particularly clearly.
In a preferred embodiment of the staple fiber yarn according to the invention, the linear density of the staple fibers A lies in the range from 0.5 to 5.0 dtex, and e.g. is 0.52 dtex, especially preferably in the range from 0.6 to 4.0 dtex wherein in each case the condition T(B):T(A)=1.5:1 to 8.8:1 is fulfilled.
In a further preferred embodiment of the staple fiber yarn according to the invention, the linear density of the staple fibers B lies in the range from 0.5 to 5.0 dtex and e.g. is 4.5 dtex, especially preferably in the range from 0.6 to 4.0 dtex wherein in each case the condition T(B):T(A) 1.5:1 to 8.8:1 is fulfilled.
The total linear density of the staple fiber yarn according to the invention lies preferably in the range from 12 to 500 tex, especially preferably in the range from 16 to 200 tex.
The staple fiber yarn according to the invention can be manufactured—as soon as the staple fibers A and B have been selected in the manner according to the invention—in principle by every method for manufacturing a staple fiber yarn, such as e.g. by a method comprising the following steps:
a) providing of staple fibers A and staple fibers B and, if necessary, additional staple fibers, whereby the staple fibers A as well as the staple fibers B consist of polymers that are selected from the groups of aramids, polyolefins, polybenzoxazoles and polybenzthiazoles, the staple fibers A having a linear density T(A) and the staple fibers B having a linear density T(B), and the linear density ratio T(B):T(A) lying in the range from 1.5:1 to 8.8:1,
b) blending at least approx. homogeneously the staple fibers A and B and, if necessary, the additional staple fibers present, in the linear density selected in step a) by producing a sliver, and
c) spinning the sliver produced in step b) into a staple fiber yarn.
Thereby, the previously mentioned process characteristics have the corresponding meaning initially explained within the description of the staple fiber yarn according to the invention.
The staple fibers A and B provided by the method according to the invention in step a) can be manufactured by one of the known methods for the manufacture of staple fibers, e.g. by shredding or preferably by cutting the corresponding filaments to the desired length, which e.g. lies in the range from 25 to 100 mm and especially preferably in the range from 30 to 60 mm.
Thereby, the previously mentioned staple fibers A and B can be manufactured exclusively from unused filaments.
However, the previously mentioned staple fibers can also be manufactured from filaments that were already in use, e.g. in a recycling process, in which an already used textile fabric, such as e.g. a woven, knitted, or crocheted fabrics made of aramid, polyolefin, polybenzoxazole or polybenzthiazole fibers has been processed into staple fibers. Preferably, the staple fibers derived through recycling in step a) of the previously described method should, however, only be provided by blending with the staple fibers manufactured from unused filaments, so that the initially described advantageous characteristics of the staple fiber yarn, produced by the previously described method, and the textile fabric manufactured from said yarn would be in effect.
The at least approx. homogeneous blending of staple fibers A and B and the, if necessary, additionally present staple fibers implemented in step b) of the method according to the invention by manufacturing a sliver can be implemented in any manner that results in the fact that at least the staple fibers A and B are at least approx. homogeneously distributed in the sliver so obtained. This means, that in every volume unit of the sliver the specified weight ratio A:B of the staple fibers A and B is at least approx. the same. For this purpose, one can employ, in principle, any method which is able to produce the desired—preferably completely homogenous—staple fiber blend, such as, e.g. sliver blending.
The spinning implemented in step c) of the method according to the invention of the sliver produced in step b) into a staple fiber yarn can be implemented by any of the known methods for manufacturing a staple fiber yarn, such as, e.g. by rotor, friction, or preferably ring spinning, such as e.g. by cotton or worsted spinning.
The underlying object of the present invention is further achieved by a textile fabric comprising a staple fiber yarn according to the invention.
Preferably, the textile fabric according to the invention is knitted, crocheted, plaited or woven.
In a further preferred embodiment, the textile fabric according to the invention has a mass per unit area in the range from 150 to 1500 g/m2, especially preferably in the range from 200 to 900 g/m2.
In a further preferred embodiment, the textile fabric is a knitted fabric, whereby the knitted fabric preferably has a knit density of 3 to 9 courses or wales and, especially preferably, of 3 to 8 courses or wales.
Finally, the underlying object of the present invention is achieved through an article that comprises the textile fabric according to the invention. At the same time, the article according to the invention profits correspondingly from the advantageous characteristics of the textile fabric, i.e. from the fabric's combination of high cut resistance with high wear comfort and appealing appearance.
Therefore, concrete embodiments of the article according to the invention are objects, in which the advantageous characteristics just mentioned are desired in whole or also only in part. For example, a preferred embodiment of the article according to the invention is a glove, an apron, a pair of pants, a jacket, a sleeve, a hose, a hose jacket or a vandalism-resistant article.
The invention will now be described in more detail by way of the following examples.
Step a): Staple fibers A and B composed of polyparaphenylene terephthalamide are used, whereby the staple fibers A have a linear density of 0.93 dtex and a length of 50 mm and the staple fibers B have a linear density of 2.5 dtex and a length of 50 mm.
Step b): Slivers are manufactured from the staple fibers A and B by sliver blending, which slivers each have a weight ratio A:B of 30:70, 50:50, and 70:30, and in which the staple fibers A and B are present in a homogeneous blend.
Step c): All slivers produced in step b) are spun by ring spinning to a staple fiber yarn according to the invention with a total linear density of 36 tex, whereby staple fiber yarns with a weight ratio of A:B of 30:70 (Example 1a), 50:50 (Example 1b), and 70:30 (Example 1c) are produced.
As a comparison, a staple fiber yarn is manufactured as described above with a total linear density of 36 tex, which yarn comprises 100 wt. % of the staple fibers B with a linear density of 2.5 dtex (Comparison Example 1V).
A glove is manufactured from each of the staple fiber yarns according to the invention from Examples 1a-c and from the staple fiber yarn from Comparison Example 1V, which glove is produced as described in the following: Two of the respective staple fiber yarns are processed into a twisted thread. Four such twisted threads are fed parallel into a knitting machine and knitted, whereby the needle gauge is 7 gg (7 needles per 2.54 cm), the mesh density is 3.5 in courses and 4 in wales.
Table 1 lists the total weight, the mass per unit area, and the thickness of the gloves produced. In addition, the table lists the lowest single value determined, according to DIN EN 388, from 10 measurements of cut resistance for each case.
Table 1 shows, that the cut resistance of the gloves manufactured from the staple fiber yarns according to the invention is 12% (compare Example 1b with Example 1V) to 25% (compare Example 1c to Example 1V) higher than the corresponding values of the glove manufactured from the comparison staple fiber yarn, although the total weight of these gloves is increased by only 2% (compare Example 1a with Example 1V) to 8% (compare Example 1c with Example 1V), and the mass per unit area of these gloves is only increased by 3% (compare Example 1a with Example 1V) to 10% (compare Example 1c with Example 1V). In addition, the thickness of the gloves manufactured from the staple fiber yarns according to the invention is 2% (compare Example 1c with Example 1V) to 6% (compare Example 1b to Example 1V) lower, so that the gloves manufactured from the staple fiber yarns according to the invention have a higher tactility than the glove manufactured from the comparison staple fiber yarn. The previously described advantageous characteristics are achieved with linear densities of the staple fibers A and B considerably less than 3 dtex, so that the gloves manufactured from the staple fiber yarns according to the invention have an agreeable wear comfort and an appealing appearance.
Step a): Staple fibers A and B composed of polyparaphenylene terephthalamide are used, whereby the staple fibers A have a linear density of 0.93 dtex and a length of 50 mm and the staple fibers B have a linear density of 2.5 dtex and a length of 50 mm.
Step b): Slivers are manufactured from the staple fibers A and B by sliver blending, which slivers each have a weight ratio A:B of 30:70 and 70:30, and in which the staple fibers A and B are present in a homogeneous blend.
Step c): All slivers produced in step b) are spun by ring spinning to a staple fiber yarn according to the invention with a total linear density of 36 tex, whereby staple fiber yarns with a weight ratio of A:B of 30:70 (Example 2a) and 70:30 (Example 2b) are produced.
As a comparison, a staple fiber yarn is manufactured as described above with a total linear density of 36 tex, which yarn comprises 100 wt. % of the staple fiber B with a linear density of 2.5 dtex (Comparison Example 2V1).
As an additional comparison, a staple fiber yarn is manufactured as described above with a total linear density of 36 tex, which yarn comprises 100 wt. % of the staple fiber A with a linear density of 0.93 dtex (Comparison Example 2V2).
A glove is manufactured from each of the staple fiber yarns according to the invention, according to Examples 2a-b, and also from the staple fiber yarn from Comparison Example 2V1, and from the staple fiber yarn from Comparison Example 2V2, which glove is produced as described in the following: Two of the respective staple fiber yarns are processed into a twisted thread. Four such twisted threads are fed parallel into a knitting machine and knitted, whereby the needle gauge is 7 gg (7 needles per 2.54 cm), the mesh density is 3.5 in courses and 4 in wales.
Table 2 lists the mass per unit area and the cut resistance, whereby the cut resistance is stated as cutting force, which is determined according to EN ISO 13997. The cutting force is the weight expressed in Newtons, which must be exerted on a blade of standardized sharpness in order to cut through the material to be examined with one straight cut of 20 mm made by the blade.
Table 2 shows that the cutting force of the gloves manufactured from the staple fiber yarns according to the invention is 15% (compare Example 2a with Example 2V1) to 17% (compare Example 2b to Example 2V1) higher than the corresponding values for the glove manufactured from the comparison staple fiber yarn. At the same time, the mass per unit area of the glove from Example 2a according to the invention is even 2% lower and the mass per unit area of the glove from Example 2b according to the invention is only 1% higher than the mass per unit area of the comparison glove from Example 2V1. The previously described advantageous characteristics are achieved with linear densities of the staple fibers A and B considerably less than 3 dtex, so that the gloves manufactured from the staple fiber yarns according to the invention have an agreeable wear comfort and an appealing appearance.
Step a): Staple fibers A and B composed of poly paraphenylene terephthalamide are used, whereby the staple fibers A have a linear density of 0.93 dtex and a length of 50 mm and the staple fibers B have a linear density of 1.7 dtex and a length of 50 mm.
Step b): Slivers are manufactured from the staple fibers A and B by sliver blending, which slivers each have a weight ratio A:B of 30:70 and 50:50, and in which the staple fibers A and B are present in a homogeneous blend.
Step c): All slivers produced in step b) are spun by ring spinning to a staple fiber yarn according to the invention with a total linear density of 36 tex, whereby staple fiber yarns with a weight ratio of A:B of 50:50 (Example 3a) and 70:30 (Example 3b) are obtained.
As a comparison, a staple fiber yarn is manufactured as described above with a total linear density of 36 tex, which yarn comprises 100 wt. % of the staple fiber B with a linear density of 1.7 dtex (Comparison Example 3V1).
As an additional comparison, a staple fiber yarn is manufactured as described above with a total linear density of 36 tex, which yarn comprises 100 wt. % of the staple fiber A with a linear density of 0.93 dtex (Comparison Example 3V2).
A glove is manufactured from each of the staple fiber yarns according to the invention, according to Examples 3a-b, and also from the staple fiber yarn from Comparison Example 3V1, and from the staple fiber yarn from Comparison Example 3V2, which glove is produced as described in the following: Two of the respective staple fiber yarns are processed into a twisted thread. Four such twisted threads are fed parallel into a knitting machine and knitted, whereby the needle gauge is 7 gg (7 needles per 2.54 cm), the mesh density is 3.5 in courses and 4 in wales.
Table 3 lists the mass per unit area and the cut resistance, whereby the cut resistance is stated as cutting force, which is determined according to EN ISO 13997.
Table 3 shows that the cutting force of the glove manufactured from the staple fiber yarn from Example 3b according to the invention is practically the same as the cutting force of the glove from Example 3V1 manufactured from the comparison staple fiber yarn with almost the same mass per unit area. This is surprising, because the aforesaid staple fiber yarn according to the invention comprises 70 wt. % staple fibers of the lower linear density, which, in light of the teaching given in WO 97/25464, should lead to a distinctly reduced cutting force.
In addition, Table 3 shows that the cutting force of the glove manufactured from the staple fiber yarn according to the invention from Example 3a is even 11% higher than the cutting force of the glove from Example 3V1 manufactured from the comparison staple fiber yarn, even though in this staple fiber yarn according to the invention, 50 wt. % of the staple fibers present have the lower linear density. At the same time, the mass per unit area of the glove according to the invention from Example 3a is even 10% lower than the mass per unit area of the comparison glove from Example 3V1. The previously described advantageous characteristics are achieved with linear densities of the staple fibers A and B considerably less than 3 dtex, so that the gloves manufactured from the staple fiber yarns according to the invention have an agreeable wear comfort and an appealing appearance.
Step a): Staple fibers A and B composed of poly paraphenylene terephthalamide are used, whereby the staple fibers A have a linear density of 0.52 dtex and a length of 50 mm and the staple fibers B have a linear density of 4.5 dtex and a length of 50 mm.
Step b): Slivers are manufactured from the staple fibers A and B by sliver blending, which slivers each have a weight ratio A:B of 30:70 and 50:50, and in which the staple fibers A and B are present in a homogeneous blend.
Step c): All slivers produced in step b) are spun by ring spinning to a staple fiber yarn according to the invention with a total linear density of 36 tex, whereby staple fiber yarns with a weight ratio of A:B of 50:50 (Example 4a) and 70:30 (Example 4b) are obtained.
As a comparison, a staple fiber yarn is manufactured as described above with a total linear density of 36 tex, which yarn comprises 100 wt. % of the staple fiber B with a linear density of 4.5 dtex (Comparison Example 4V1).
As an additional comparison, a staple fiber yarn is manufactured as described above with a total linear density of 36 tex, which yarn comprises 100 wt. % of the staple fiber A with a linear density of 0.52 dtex (Comparison Example 4V2).
A glove is manufactured from each of the staple fiber yarns according to the invention, according to Examples 4a-b, and also from the staple fiber yarn from Comparison Example 4V1, and from the staple fiber yarn from Comparison Example 4V2, which glove is produced as described in the following: Two of the respective staple fiber yarns are processed into a twisted thread. Four such twisted threads are fed parallel into a knitting machine and knitted, whereby the needle gauge is 7 gg (7 needles per 2.54 cm), the mesh density is 3.5 in courses and 4 in wales.
Table 4 lists the mass per unit area and the cut resistance, whereby the cut resistance is stated as cutting force, which is determined according to EN ISO 13997.
Table 4 shows that the cutting force of the glove manufactured from the staple fiber yarn from Example 4b according to the invention is 15% higher than the cutting force of the glove from Example 4V1 manufactured from the comparison staple fiber yarn with a mass per unit area which is only 3% lower than the mass per unit area of the glove according to the invention example 4b. This is surprising, because the aforesaid staple fiber yarn according to the invention comprises 70 wt. % staple fibers of the lower linear density, which, in light of the teaching given in WO 97/25464, should lead to a distinctly reduced cutting force. In addition, Table 4 shows that the cutting force of the glove manufactured from the staple fiber yarn according to the invention from Example 4a is 12% higher than the cutting force of the glove from Example 4V1 manufactured from the comparison staple fiber yarn, even though in this staple fiber yarn according to the invention, 50 wt. % of the staple fibers present have the lower linear density. At the same time, the mass per unit area of the glove according to the invention from Example 4a is only 2% higher than the mass per unit area of the comparison glove from Example 4V1.
| Number | Date | Country | Kind |
|---|---|---|---|
| 06016797.0 | Aug 2006 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2007/006743 | 7/31/2007 | WO | 00 | 1/12/2009 |
