WO2018153844A1

WO2018153844A1 - Textile fabric and workwear manufactured thereof

Info

Publication number: WO2018153844A1
Application number: PCT/EP2018/054117
Authority: WO
Inventors: Regine Zumloh-Nebe; Jutta Krabbe
Original assignee: Teijin Aramid GmbH
Current assignee: Teijin Aramid GmbH
Priority date: 2017-02-27
Filing date: 2018-02-20
Publication date: 2018-08-30
Anticipated expiration: 2019-08-27
Also published as: EP3585927A1; CN110446805B; ES2948636T3; KR20190117668A; RU2019129085A; RU2019129085A3; JP2020510762A; CN110446805A; KR20230169408A; JP7044798B2; RU2753284C2; EP3585927B1

Abstract

A textile fabric is provided comprising a staple fiber yarn made of a staple fiber blend, wherein the blend comprises meta-aramid staple fibers, para-aramid staple fibers, and poly lactic acid staple fibers. The textile fabric is used to manufacture workwear.

Description

Textile fabric and workwear manufactured thereof

Description:

The present invention pertains to a textile fabric and workwear manufactured thereof. Textile fabrics are known. This type of fabrics should especially be heat protective and should also exhibit sufficient mechanical properties, for example sufficient tear strength.

US 201 1 /0138523 A1 describes a heat, flame and electric arc protective for use as single layer of a protective garment for a wearer, the fabric comprising: interwoven warp and weft yarn wherein the warp and weft yarn comprises a blend of 8 to 33 wt.-% meta-aramid staple fibers, 65 to 90 wt.-% para-aramid staple fibers, and 2 wt.-% anti-static staple fibers, the weft yarn and warp yarn being identical and comprising the side of the fabric facing away from a wearer and the side of the fabric facing the wearer, wherein the fabric provides ablative thermal protection on both sides. In an example a fabric with a twill K 21 1 Z construction and with a grammage of 230 g/m² exhibits a tear resistance of the warp to be 67.87 N and of the weft to be 34.4 N, measured using the ISO 13937-1 :2000 test procedure. EP 1740746 B1 describes a heat and flame resistant fabric for use as single or outer layer of protective garments. This fabric comprises fibers with a blend of 60 to 90 wt.-% of meta-aramid staple fibers and 5 to 40 wt.-% of para-aramid fibers. This fabric does not comprise polylactide staple fibers. WO 02/40755 A2 describes a fire resistant corespun yarn comprising a core of high temperature resistant continuous inorganic filaments and a first and a second sheath of staple fibers. The first sheath comprises natural and synthetic staple fibers with at least one fire retardant fiber. The staple fibers of the second sheath are selected from natural staple fibers or synthetic staple fibers. WO 02/40755 A2 is silent about a blend of meta-aramid staple fibers and para-aramid staple fibers with poly lactic acid staple fibers. Furthermore, a staple fiber composition DuPont™ Nomex^® IMA is known consisting of 93 % Nomex^® m-aramid staple fibers, 5 % Kevlar^® p-aramid staple fibers, and 2 % antistatic staple fibers. According to an internet presentation of DuPont a fabric made of the staple fiber composition DuPont™ Nomex^® IMA meets the NFPA 1975 standard for firefighters' station wear and is resistant to abrasion and tears.

However, there is an ongoing demand for heat protective textile fabrics with better mechanical properties, especially with higher resistance to tear and abrasion, because said fabrics are used to manufacture work wear which should have an as high as possible abrasion resistance and tear strength so that the fabrics can be worn for an as long as possible time. Furthermore, there is an ongoing demand for heat protective textile fabrics with better wear comfort, because said fabrics are often worn during high physical fatigue which should not be further increased by an uncomfortable feeling caused by the work wear.

Therefore, the problem underlying the present invention is to provide a fabric which exhibits higher tear strength and higher wear comfort in garments, especially workwear made thereof. Said problem is solved by a textile fabric comprising a staple fiber yarn made of a staple fiber blend, wherein the blend comprises meta-aramid staple fibers, para- aramid staple fibers, and poly lactic acid staple fibers. Surprisingly, the textile fabric according to the invention exhibits a higher resistance against abrasion and tear than a comparative textile fabric made from a staple fiber yarn which was manufactured from a staple fiber mixture consisting of meta-aramid staple fibers, para-aramid staple fibers and antistatic staple fibers. So, a garment comprising the textile fabric according to the invention can be worn for a longer time before it becomes damaged.

Furthermore, the higher values for resistance to abrasion and tear of the textile fabric according to the invention can be obtained with a lower grammage of the textile fabric, if compared with the grammage of a comparative textile fabric made of a staple fiber yarn which was manufactured from a staple fiber mixture consisting of meta-aramid staple fibers, para-aramid staple fibers and antistatic staple fibers. So, a garment comprising the textile fabric according to the invention can be worn with a higher wear comfort than a garment comprising the

comparative textile fabric. Alternatively, a garment comprising the textile fabric according to the invention, wherein the grammage of the textile fabric is increased to the value of the grammage of the comparative textile fabric, can be worn with the same wear comfort as the garment comprising the comparative textile fabric but for an even longer time, because the resistance of the garment with the textile fabric of the invention to abrasion and tear is even more increased.

Though poly lactic acid - in contrast to meta-aramid and para-aramid - is not intrinsically heat and flame resistant, the textile fabric according to the present invention surprisingly fulfills the minimum requirements in terms of radiant heat, convective heat, and contact heat. Finally, if the garment comprising the textile fabric according to the invention has to be discarded, the poly lactic acid component of the textile fabric can be fully recycled, because poly lactic acid is fully biodegradable resulting in compost. The compost can be used as substrate to grow corn. The corn can be fermented to lactic acid which can be polymerized to poly lactic acid from which poly lactic acid staple fibers can be manufactured. Therefore, the textile fabric according to the invention contains a renewable component.

Within the scope of the present invention the term "staple fibers" means fibers of limited length obtained from cutting or breaking a filament yarn.

Within the scope of the present invention the term "meta-aramid staple fibers" means staple fibers obtained from cutting or breaking a meta-aramid filament yarn, and the term "meta-aramid" means a polymer obtained by the polycondensation of a meta-oriented aromatic diamine and a meta-oriented dicarboxylic acid halide, wherein said polymer exhibits recurring units having amide bonds, and preferably at least 85 % of said amide bonds are located in the meta-oriented positions of the aromatic ring. Within the scope of the present invention the term "para-aramid staple fibers" means staple fibers obtained from cutting or breaking a para-aramid filament yarn, and the term "para-aramid" means a polymer obtained by the polycondensation of a para-oriented aromatic diamine and a para-oriented dicarboxylic acid halide of which recurring units have amide bonds, and preferably at least 65 %, more preferably at least 95 % and even more preferably at least 99 %, and most preferred 100 % of said amide bonds are located in the para-oriented positions of the aromatic ring.

Within the scope of the present invention the term "aramid staple fibers" means staple fibers obtained from cutting or breaking an aramid filament yarn. The term aramid means a polymer, wherein aromatic moieties are connected to one another by amide bonds. Usually aramid are synthesized by poly-condensation of aromatic diamines with aromatic dihalides. Aramid includes meta-aramid, para-aramid and aramid-copolymers such as copolymer [co-poly-(paraphenylene/3,4'- oxydiphenylene terephthalamide)] (Technora®).

Within the scope of the present invention the term "poly lactic acid staple fibers" means staple fibers obtained from cutting or breaking a poly lactic acid filament yarn, and the term "poly lactic acid" means a polymer having lactide recurring units and, therefore, is also called "polylactide".

Within the scope of the present invention the term "staple fiber blend" means an intimate mixture of the meta-aramid staple fibers, the para-aramid staple fibers, and the poly lactic acid staple fibers so that in each volume element of the staple fiber blend the same weight ratio of para-aramid staple fibers to meta-aramid staple fibers to poly lactic acid staple fibers is present. Said intimate mixture may for example be obtained by intermingling the meta-aramid staple fibers, the para- aramid staple fibers, and the poly lactic acid staple fibers in air.

Within the scope of the present invention the term "staple fiber yarn" means a yarn which has been manufactured from the staple fiber blend of the meta-aramid staple fibers, the para-aramid staple fibers, and the poly lactic acid staple fibers, by any known method to produce a staple fiber yarn, for example by ring spinning, or by open-end spinning such as air-jet spinning. Within the scope of the present invention the term "textile fabric" means a blend of staple fibers spun to yarns which are arranged in a certain fabric structure.

In a preferred embodiment of the textile fabric according to the present invention the blend comprises

- 30 to 90 wt.-% of the meta-aramid staple fibers,

- 5 to 60 wt.-% of the para-aramid staple fibers, and - 5 to 40 wt.-% of the poly lactic acid staple fibers

with respect to a weight of the blend.

In a more preferred embodiment of the textile fabric according to the present invention the blend comprises

- 40 to 85 wt.-% of the meta-aramid staple fibers,

- 5 to 50 wt.-% of the para-aramid staple fibers, and

- 5 to 30 wt.-% of the poly lactic acid staple fibers

with respect to a weight of the blend.

In a most preferred embodiment of the textile fabric according to the present invention the blend comprises

- 50 to 85 wt.-% of the meta-aramid staple fibers,

- 10 to 40 wt.-% of the para-aramid staple fibers, and

- 5 to 25 wt.-% of the poly lactic acid staple fibers

with respect to a weight of the blend.

In an embodiment of the textile fabric according to the present invention the blend comprises at most 95 % of aramid staple fibers, preferably at most 90 % of aramid staple fibers, more preferably at most 80 % of aramid staple fibers, or at most 70 % of aramid staple fibers with respect to a weight of the blend.

In an embodiment of the textile fabric according to the present invention the blend comprises at least 40 % of meta-aramid staple fibers, preferably at least 50 % meta-aramid staple fibers and more preferably at least 60 % of meta-aramid staple fibers with respect to a weight of the blend.

In an embodiment of the textile fabric according to the present invention the blend comprises at most 85 % of meta-aramid staple fibers, more preferably at most 75 % meta-aramid staple fibers or at most 65 % of meta-aramid staple fibers with respect to a weight of the blend. In an embodiment of the textile fabric according to the present invention the blend comprises at least 10 % of para-aramid staple fibers, preferably at least 20 % para-aramid staple fibers and more preferably at least 30 % of para-aramid staple fibers with respect to a weight of the blend.

In an embodiment of the textile fabric according to the present invention the blend comprises at most 50 % of para-aramid staple fibers, more preferably at most 40 % para-aramid staple fibers or at most 35 % of para-aramid staple fibers with respect to a weight of the blend.

In an embodiment of the textile fabric according to the present invention the blend comprises at least 10 % of poly lactic acid staple fibers, preferably at least 15 % poly lactic acid staple fibers and more preferably at least 20 % of poly lactic acid staple fibers with respect to a weight of the blend.

In an embodiment of the textile fabric according to the present invention the blend comprises at most 35 % of poly lactic acid staple fibers, more preferably at most 30 % poly lactic acid staple fibers or at most 25 % of poly lactic acid staple fibers with respect to a weight of the blend.

As mentioned before, the term "staple fibers" means fibers of limited length obtained from cutting or breaking a filament yarn. If the staple fibers are obtained by breaking, the staple fibers exhibit a length distribution which is characteristic for the breaking technology which was applied, e.g., stretch-breaking.

Preferably, the staple fibers are obtained by cutting a filament yarn into a unitary length which is preset in the used cutting device. This results in staple fibers which have a unitary length.

In a preferred embodiment of the textile fabric according to the present invention the meta-aramid staple fibers have a unitary length of 30 to 140 mm, the para- aramid staple fibers have a unitary length of 30 to 140 mm, and the poly lactic acid staple fibers have a unitary length of 30 to 140 mm. In a more preferred embodiment of the textile fabric according to the present invention the meta-aramid staple fibers have a unitary length of 30 to 130 mm, the para-aramid staple fibers have a unitary length of 30 to 130 mm, and the poly lactic acid staple fibers have a unitary length of 30 to 130 mm.

In a most preferred embodiment of the textile fabric according to the present invention the meta-aramid staple fibers have a unitary length of 30 to 120 mm, the para-aramid staple fibers have a unitary length of 30 to 120 mm, and the poly lactic acid staple fibers have a unitary length of 30 to 120 mm.

In a preferred embodiment of the textile fabric according to the present invention the meta-aramid staple fibers have a linear density of 0.8 to 7 dtex, the

para-aramid staple fibers have a linear density of 0.8 to 7 dtex, and the poly lactic acid staple fibers have a linear density of 0.8 to 7 dtex.

In a more preferred embodiment of the textile fabric according to the present invention the meta-aramid staple fibers have a linear density of 0.8 to 6 dtex, the para-aramid staple fibers have a linear density of 0.8 to 6 dtex, and the poly lactic acid staple fibers have a linear density of 0.8 to 6 dtex.

In a most preferred embodiment of the textile fabric according to the present invention the meta-aramid staple fibers have a linear density of 0.8 to 5 dtex, the para-aramid staple fibers have a linear density of 0.8 to 5 dtex, and the poly lactic acid staple fibers have a linear density of 0.8 to 5 dtex.

In a preferred embodiment of the textile fabric according to the present invention the blend additionally comprises up to 5 wt.-%, preferably from 0 to 4 wt.-% and most preferred from 0 to 3 wt.-% of antistatic staple fibers with respect to a weight of the blend. Preferably the antistatic staple fibers comprise polyester, carbon or steel or mixtures thereof as the antistatic fiber forming polymer. In a preferred embodiment of the textile fabric according to the present invention the antistatic staple fibers have a length of 30 to 140 mm, and a linear density of 0.8 to 7 dtex. In a more preferred embodiment of the textile fabric according to the present invention the antistatic staple fibers have a length of 30 to 130 mm and a linear density of 0.8 to 6 dtex.

In a most preferred embodiment of the textile fabric according to the present invention the antistatic staple fibers have a length of 30 to 120 mm and a linear density of 0.8 to 5 dtex.

Preferably, the meta-aramid staple fibers comprised by the staple fiber blend exhibit a crimp with a crimp value which preferably ranges from 2 to 13 crimps per cm, more preferably from 3 to 10 crimps per cm.

Preferably, the para-aramid staple fibers comprised by the staple fiber blend exhibit a crimp with a crimp value which preferably ranges from 2 to 13 crimps per cm, more preferably from 3 to 10 crimps per cm.

Preferably, the poly lactic acid staple fibers comprised by the staple fiber blend exhibit a crimp with a crimp value which preferably ranges from 3 to 13 crimps per cm, more preferably from 5 to 10 crimps per cm. In a preferred embodiment of the textile fabric according to the invention the staple fibers comprised by the staple fiber blend, including aramid staple fibers, exhibit a crimp value of 2 to 13 crimps per cm, preferably a crimp value of 3 to 10 crimps per cm and poly lactic acid staple fibers, exhibit a crimp value of 3 to 13 crimps per cm, preferably a crimp value of 4 to 10 crimps per cm. In a preferred embodiment of the textile fabric according to the present invention the meta-aramid staple fibers are poly(meta-phenylene isophthalamide) staple fibers which preferably have been spun from a solution comprising poly(meta- phenylene isophthalamide) in dimethyl acetamide, the para-aramid staple fibers are poly-(p-phenylene terephthalamide) staple fibers or poly(p-phenylene-3,4'- oxydiphenylene terephthalamide) staple fibers, and the poly lactic acid staple fibers are poly-L-lactic acids staple fibers or poly-D-lactic acid staple fibers or staple fibers made of a racemic mixture of poly-L-lactic acid and poly-D-lactic acid or staple fibers made of a stereo complex of poly-L-lactic acid and poly-D-lactic acid .

Macromolecules of identical chemical composition but different configuration of repeating units are able to form an intermolecular complex called stereo complex. Stereo complex formation of polylactides occurs due to non-covalent interactions of enantiomeric chains of poly-L-lactic acid (PLLA) and poly-D-lactic acid (PDLA) and results in higher thermal stability. Preferably, the PLLA and PDLA are arranged alternatively in the stereo complex to form a crystal structure.

In a preferred embodiment of the textile fabric according to the present invention the yarn is manufactured from the blend by ring spinning or air jet spinning.

The textile fabric according to the present invention may in principle be any network of fibers which are arranged in a certain fabric structure and which is suited to form a garment.

Preferably, the textile fabric according to the present invention is a woven or knitted textile fabric.

Furthermore, it is preferred that the textile fabric according to the present invention has a twill or plain weave construction. It is also preferred that the textile fabric according to the invention has a twill or plain weave construction comprises at least one warp system and at least one weft system, and the at least one warp system and the at least one weft system comprise yarns with the same blend of staple fibers or yarns with different blends of staple fibers.

Preferably, the textile fabric according to the present invention has a grammage of 50 to 400 g/m², more preferred 80 to 380 g/m², and most preferred 100 to 350 g/m².

The advantageous properties of the textile fabric according to the present invention transform themselves to a garment which is manufactured using said textile fabric. Such a garment comprises at least one textile fabric according to the invention. Due to the improved abrasion resistance and pilling resistance, such garments are especially suited for workwear. Therefore, the use of said textile fabric to manufacture workwear is also part of the present invention.

The present invention is explained in more detail in the following non-limiting examples.

Examples

Sample preparation: Example 1 (according to the invention)

a) Manufacturing of a staple fiber blend (Example 1)

An intimate staple fiber blend consisting of

- 25 wt.-% poly(p-phenylenterephthalamide) staple fibers of Type Twaron 1070 having a length of 40 mm, a linear density of 1 .7 dtex, and a crimp value of 4 to 8 crimps per cm.

- 65 wt.-% poly(m-phenylenisophthalamide) staple fibers of Type TeijinConex T BL1 , which have been spun from a solution comprising poly(meta-phenylene isophthalamide) in dimethyl acetamide having a length of 50 mm and

a linear density of 1 .7 dtex, and a crimp value of 3 to 7 crimps per cm, and

- 10 wt.-% poly lactic acid staple fibers "ingeo" obtained from RMB fibers AG (CH) having a length of 38 mm, a linear density of 1 .5 dtex, a tenacity of

38 cN/tex, an elongation at break of 40 %, a crimp value of 7 crimps per cm, and a boiling water shrinkage of 5.4 %

was manufactured by intimately blending the above staple fibers with the above weight percentages. b) Manufacturing of a staple fiber yarn (Example 1)

From the staple fiber blend which resulted in step a) two Nm 40/1 staple fiber yarns were manufactured. Said two Nm 40/1 staple fiber yarns were twisted to result in a Nm 40/2 twisted staple fiber yarn. c) Manufacturing of a woven fabric (Example 1)

From the Nm 40/2 twisted staple fiber yarn which resulted in step b) a woven fabric was manufactured having the construction 21 1 Z according to DIN EN ISO 721 1 -1 , i.e., a twill weave exhibiting two lifts and one lowering in Z-direction, wherein both the warp threads and the weft threads consist of the staple fiber yarn which resulted in step b). The textile fabric consists of warp threads with a thread density of 191 threads/10 cm and of weft threads with a thread density of 182 threads/10 cm. The thread density was determined according to DIN EN ISO 1049-2.

The grammage of the woven fabric amounts to 202 g/m² and was determined according to DIN EN ISO 12127.

Comparative Example 1 (CE1)

a) Providing a comparative staple fiber blend (CE1)

A comparative staple fiber blend obtained from DuPont (USA) under the trade name Nomex® MIA was provided consisting of

- 5 wt.% poly(p-phenylenterephthalamide) DuPont™ Kevlar® staple fibers having a unitary length of 50 mm, a linear density of 1 .7 dtex,

- 93 wt.-% poly(m-phenylenisophthalamide) DuPont™ Nomex® staple fibers> having a length of 50 mm, a linear density of 1 .7 dtex, and a crimp value of crimps per cm, and

- 2 wt.-% antistatic staple fibers having a unitary length of 50 mm, a linear density of 1 .7 dtex. b) Manufacturing of comparative staple fiber yarns (CE1)

From the Nomex® IMA staple fiber mixture provided in step a) one Nm 60/1 staple fiber yarn and one Nm 60/1 staple fiber yarn were manufactured. Said two staple fiber yarns were twisted to result in a comparative Nm 60/2 twisted staple fiber yarn. c) Manufacturing of a comparative woven fabric (CE1)

A comparative textile fabric was manufactured having the construction 21 1 Z according to DIN EN ISO 721 1 -1 , i.e., a twill weave exhibiting two lifts and one lowering in Z-direction, wherein both the warp threads and the weft threads consist of the comparative twisted staple fiber yarn which resulted in step b). The textile fabric consists of warp threads with a thread density of 386 threads/10 cm and of weft threads with a thread density of 244 threads/10 cm. The thread density was determined according to DIN EN ISO 1049-2. The grammage of the comparative textile fabric amounts to 225 g/m² and was determined according to

DIN EN ISO 12127.

Comparative Example 2 (CE2)

a) Providing a comparative staple fiber blend (CE2)

A comparative staple fiber blend consisting of

- 60 wt.-% poly(p-phenylenterephthalamide) staple fibers of Type Twaron 1072 having a length of 50 mm, a linear density of 1 .7 dtex, and a crimp value of 4 to 9 crimps per cm and

- 40 wt.-% poly(m-phenylenisophthalamide) staple fibers of Type TeijinConex YE5, which have been spun from a solution comprising poly(meta-phenylene isophthalamide) in dimethyl acetamide having a length of 50 mm and a linear density of 1 .7 dtex, and a crimp value of 3 to 7 crimps per cm was manufactured by intimately blending the above staple fibers with the above weight percentages. The manufacturing process b) of the staple fiber yarns of CE 2 and the manufacturing process c) of the woven fabric of CE 2 is performed as for Comparative Example 1 (CE1 ).

The value of threads/1 Ocm of the woven fabric amounts to 188 warp-threads and 199 weft-threads and was determined according to DIN EN ISO 1049-2.

The grammage of the woven fabric amounts to 204 g/m² and was determined according to DIN EN ISO 12127.

Comparative Example 3 (CE3)

a) Providing a comparative staple fiber blend (CE3)

A comparative staple fiber blend consisting of

- 40 wt.-% poly(p-phenylenterephthalamide) staple fibers of Type Twaron 1072 having a length of 50 mm, a linear density of 1 .7 dtex, and a crimp value of 4 to 9 crimps per cm and

- 60 wt.-% poly(m-phenylenisophthalamide) staple fibers of Type TeijinConex YE5, which have been spun from a solution comprising poly(meta-phenylene isophthalamide) in dimethyl acetamide having a length of 50 mm and a linear density of 1 .7 dtex, and a crimp value of 3 to 7 crimps per cm was manufactured by intimately blending the above staple fibers with the above weight percentages.

The manufacturing process b) of the staple fiber yarns of CE 3 and the

manufacturing process c) of the woven fabric of CE 3 is performed as for

Comparative Example 1 (CE1 ).

The value of threads/10cm of the woven fabric amounts to 188 warp-threads and 179 weft-threads and was determined according to DIN EN ISO 1049-2. The grammage of the woven fabric amounts to 204 g/m² and was determined according to DIN EN ISO 12127.

For the purpose of clarity the staple fiber blend compositions of example 1 and of the comparative examples (CE1 to CE3) are shown in table 1 .

Table 1

Example 1 , CE1 CE2 CE3 acc. to the

invention

para-aramid

staple fibers 25 5 60 40

[%]

meta-aramid

staple fibers 65 93 40 60

[%]

poly lactic acid

staple fibers 10

[%]

antistatic

2

staple fibers Methods

The properties of the woven fabric and of the comparative woven fabrics were determined as follows:

- the tensile strength [N] and the elongation at break [%] of the woven fabric according to the invention and of the comparative woven fabric both measured according to DIN EN ISO 13934-1 ,

- the tensile strength [N] of the staple fiber yarn according to the invention measured according to DIN EN ISO 13934-1 ,

- the tear strength [N] of the woven fabric according to the invention and of the comparative woven fabric both measured according to DIN EN ISO 13937-2,

- the pilling resistance of the woven fabric according to the invention and of the comparative woven fabric both measured according to DIN EN ISO 12945-2 after a certain number of cycles, wherein assessment 1 represents the lowest pilling resistance and assessment 5 means the highest pilling resistance,

- the abrasion resistance of the woven fabric according to the invention and of the comparative textile fabric both measured according to DIN EN ISO 12947-2 after a certain number of cycles till complete destruction of two threads in the sample was detected, wherein each 3 samples were measured and the arithmetic mean value of the abrasion resistances of the 3 samples was calculated, - the convective heat of the woven fabric according to the invention measured according to ISO 9151 and resulting in the Heat Transfer Index t_Hn [s], i.e., the time in seconds after which a calorimeter installed in a certain distance above the textile fabric measures a temperature increase of 24 °C, wherein the textile fabric is arranged at a certain distance above a Bunsen burner burning with 80 kW/m²,

- the radiant heat of the woven fabric according to the invention measured according to ISO 6942 and resulting in t₂₄°c, 20kw m² [s] and t₂₄°c,₄okw/m² [s], i.e., the time in seconds after which on one side of the textile fabric a temperature increase of 24 °C is measured, wherein the textile fabric is arranged at a calibrated distance from a radiant heat source radiating with 20 kW/m² or

80 kW/m², thereby simulating the breakthrough time of radiant heat in the case of operation, after which second-degree burns are expected,

- the contact heat of the woven fabric according to the invention measured according to ISO 12127 and resulting in the threshold time tt_hreshoid [s], i.e., the time in seconds after which a calorimeter installed under the textile fabric in a certain distance measures a temperature increase of 10 °C, wherein the textile fabric is in contact with a drum having a temperature of 250 °C,

- the heat shrinkage of the woven fabric in [%] at 180 °C, and

- the heat shrinkage of the woven fabric in [%] at 250 °C.

For the tensile strength [N], the elongation at break [%], and the tear strength [N] the standard deviations are given, wherein each five samples were measured in warp and in weft direction.

Experimental results

Experiment 1

In Experiment 1 two woven fabrics (Example 1 according to the invention and Comparative Example 1 ) are tested to compare their properties. The results are shown in table 2. Table 2

Example 1 acc. CE1 to the invention

warp weft warp weft

Threads/10cm 191 182 386 244

Fabric grammage [g/m²] 202 225

Tensile strength of the 1151 1097 1169 1097 woven fabric [N] ± 39.0 ± 36.0 ±15.3 ±9.5

Elongation at break of 10.0 11.5 47.0 32.3 woven fabric [%] ± 0,5 ± 0,3 ±2,0 ±0,5

Tensile strength of the 12.1 12.1

yarn [N] ±0.4 ±0.4

Tear strength of the 72.2 75.9 54.4 54.7 woven fabric [N] ±0.8 ±6.2 ±1.8 ±1.5

Pilling resistance of the assessment assessment woven fabric after

125 cycles 4-5 5

500 cycles 4 4 1000 cycles 3-4 3 2000 cycles 3 3 5000 cycles 3 3-2 7000 cycles 3 3-2

Abrasion resistance 120000 70000 - 80000 of the woven fabric cycles cycles

Convective heat t_Hn [s] 5.1

of the woven fabric assessment B1

radiant heat t₂ °_c,20kw/m² [s] 11.2

of the woven fabric assessment C1

radiant heat t₂ °_c, okw/m² [s] 6.4

of the woven fabric

contact heat foreshow [s] 7.2

of the woven fabric assessment F1

heat shrinkage [%] 2.5 0.5

of the woven fabric at 180 °C

heat shrinkage [%] 3.2 1.0

of the woven fabric at 250 °C From table 2 the following can be concluded:

The abrasion resistance of the woven fabric according to the invention (120 000 cycles) is 33 % to 42 % higher than the abrasion resistance of the comparative woven fabric (70 000 to 80 000 cycles).

The warp tear resistance, i.e., the warp tear strength of the woven fabric according to the invention (72.2 N) is 33 % higher than the warp tear strength of the comparative woven fabric (54.4 N), and the weft tear strength of the woven fabric according to the invention (75.9 N) is 39 % higher than the weft tear strength of the comparative woven fabric (54.7 N).

The higher resistances against tear and abrasion of the woven fabric according to the invention are obtained with a fabric grammage of 202 g/m², i.e., with a fabric grammage that is 10 % lower than the fabric grammage of the comparative woven fabric (225 g/m²).

Though the woven fabric according to the invention contains 10 wt.-% of poly lactic acid which is not intrinsically heat and flame resistant, the woven fabric according to the invention exhibits

- a convective heat expressed as t_Hxi of 5.1 s which is assessed to be B1 ,

- a radiant heat expressed as t₂₄°c,20kw/m² of 1 1 .2 s which is assessed to be C1 , and

- a contact heat expressed as shoid of 7.2 s which is assessed to be F1 .

Said assessments are defined in DIN EN ISO 1 1612 and mean that the woven fabric fulfills the minimum requirements for heat and flame protective clothing.

Experiment 2

In Experiment 2 three woven fabrics (Example 1 according to the invention and Comparative Example 2 and 3) are tested to compare their properties. CE3 is a comparative example similar to Example 1 . It contains a similar amount of para- aramid staple fibers and meta-aramid staple fibers, but no poly lactic acid staple fibers. The results are shown in table 3.

Table 3

From table 3 the following can be concluded:

The abrasion resistance of the Example 1 according to the invention shows with 120 000 cycles a 50 % to 100 % higher value than the comparative woven fabrics (CE2: 60 000; CE3: 80 000 cycles).

The pilling resistance of Example 1 according to the invention is at least one level higher than the pilling resistance of CE2 and CE3 and at a higher number of cycles the difference between Example 1 and CE2 and CE3 becomes more apparent. In case of 5000 and 7000 cycles the difference is two levels. The comparison of Example 1 with CE3 shows that the Example 1 with poly lactic acid staple fibers has a better pilling resistance and abrasion resistance.

Claims

Textile fabric and workwear manufactured thereof Claims:

1 . Textile fabric comprising a staple fiber yarn made of a staple fiber blend, wherein the blend comprises meta-aramid staple fibers, para-aramid staple fibers, and poly lactic acid staple fibers.

2. Textile fabric according to claim 1 , wherein the blend comprises

- 30 to 90 wt.-% of the meta-aramid staple fibers,

- 5 to 60 wt.-% of the para-aramid staple fibers, and

- 5 to 40 wt.-% of the poly lactic acid staple fibers

with respect to a weight of the blend.

3. Textile fabric according to claim 1 or 2, wherein the meta-aramid staple fibers have a unitary length of 30 to 140 mm, the para-aramid staple fibers have a unitary length of 30 to 140 mm, and the poly lactic acid staple fibers have a unitary length of 30 to 140 mm.

4. Textile fabric according to one or more of claims 1 to 3, wherein the meta- aramid staple fibers have a linear density of 0.8 to 7 dtex, the

5. Textile fabric according to claim 1 to 4, wherein the blend additionally comprises up to 5 wt.-% of antistatic staple fibers with respect to a weight of the blend.

6. Textile fabric according to claim 5, wherein the antistatic staple fibers have a length of 30 to 140 mm, and a linear density of 0.8 to 7 dtex.

7. Textile fabric according to one or more of claims 1 to 6, wherein the meta- aramid staple fibers are poly(meta-phenylene isophthalamide) staple fibers, the para-aramid staple fibers are poly-(p-phenylene terephthalamide) staple fibers or poly(p-phenylene-3,4'-oxydiphenylene terephthalamide) staple fibers, and the poly lactic acid staple fibers are poly-L-lactic acids staple fibers or poly-D-lactic acid staple fibers or staple fibers made of a racemic mixture of poly-L-lactic acid and poly-D-lactic acid or staple fibers made of a stereo complex of poly-L-lactic acid and poly-D-lactic acid.

8. Textile fabric according to one or more of claims 1 to 7, wherein the yarn is manufactured from the blend by ring spinning or air jet spinning.

9. Textile fabric according to one or more of claims 1 to 8, wherein the textile fabric is a woven or knitted textile fabric.

10. Textile fabric according to claim 9, wherein the textile fabric is a woven

textile fabric having a twill or plain construction.

1 1 .Woven textile fabric according to claim 10, wherein the twill or plain weave construction comprises at least one warp system and at least one weft system, and the at least one warp system and the at least one weft system comprise yarns with the same blend of staple fibers or yarns with different blends of staple fibers.

12. Textile fabric according to one or more of claims 1 to 1 1 , wherein the textile fabric has a grammage of 50 to 350 g/m².

13. Textile fabric according to one or more of claims 1 to 12, wherein the blend comprises at most 95 % of aramid staple fibers, preferably at most 90 % aramid staple fibers, more preferably at most 80 % aramid staple fibers, or at most 70 % or aramid staple fibers with respect to a weight of the blend.

14. A garment comprising at least one textile fabric according to one or more of claims 1 to 13.

15. Use of the textile fabric according to one or more of claims 1 to 13 to

manufacture workwear.