EP3540106A1

EP3540106A1 - Yarn and fabric comprising the yarn

Info

Publication number: EP3540106A1
Application number: EP18168836.7A
Authority: EP
Inventors: Omer AHMED; Hafiz KASHIF
Original assignee: Blue Star Denim LLC
Current assignee: Blue Star Denim LLC
Priority date: 2018-03-14
Filing date: 2018-04-23
Publication date: 2019-09-18

Abstract

The invention relates to a yarn and a fabric comprising the yarn. The invention seeks at providing a yarn with a flame retardant property from which a lightweight fabric with a flame retardant property is producible. Proposed is a yarn for producing a fabric, comprising first synthetic fibers 1, second synthetic fibers 2 and regenerated cellulose fibers 3. The first synthetic fibers 1, the second synthetic fibers 2 and the regenerated cellulose fibers 3 are different types of fibers. The first synthetic fibers 1 have a first flame retardant property, wherein the first flame retardant property is an inherent property of the first synthetic fibers 1. The second synthetic fibers 2 have a second flame retardant property, wherein the second flame retardant property is an inherent property of the second synthetic fibers 2. The yarn is suitable for producing a fabric with an area related mass of at most 14 ounces per square yard (475 grams per square meter) and with a flame retardant property.

Description

The invention relates to a yarn and a fabric comprising the yarn. Specifically, the invention relates to a yarn from which a (denim) fabric with a flame retardant property is producible. The fabric can be used to produce a garment with enhanced safety properties for protecting a person wearing the garment. Such safety properties can be e.g. flame and/or heat resistance, electric arc resistance, abrasion resistance and/or anti-static properties.
For example, in the electrical, oil and gas industry workers are often subjected to harsh and dangerous environmental and working conditions. Oil field workers can be faced with open fire during their work routine. Therefore, these workers often wear garments with a flame retardant property in order to protect them from injuries or reduce injuries.
Such garments are often heavy and uncomfortable. For these reasons, the agility of workers wearing these garments is often limited what in turn raises safety issues and exhausts workers. Thus, lightweight garments with a flame retardant property that are comfortable to wear are needed.
Sometimes comfortable and lightweight garments are treated with flame (fire) retardant compounds, because fibers of the yarn from which the garments are produced do not have an inherent flame retardant property. Often these compounds are water soluble and washing the garments in a common washing machine removes the compound whereby the flame retardant property of the garments is lost after several washing cycles. Therefore, lightweight and comfortable garments that keep their flame retardant property after several (e.g. 20) washing cycles are needed.
It is also desirable to have garments with a flame retardant property that have the look of regular garments. For example, workers from the above mentioned industries are often uncomfortable wearing certain garments with a flame retardant property in public places.
As the working environment of workers from the above mentioned industries is often harsh, it is desirable to have garments with an enhanced abrasion property in addition to the flame retardant property.
Static electrical discharges, caused by a build-up of electrostatic charge of garments that discharges when being close to a conductor, can cause fires in environments with flammable components, e.g. in oil or gas fields. Thus, the above mentioned garments are often wanted to have anti-static properties.
Electric arcs from e.g. voltage sources to workers can cause heavy injuries. The above mentioned garments are often wanted to have an enhanced electric arc resistance.
The problem to be solved by the invention is to provide a yarn with an inherent flame retardant property from which a lightweight fabric with a flame retardant property can be produced. It is another problem to be solved to provide a yarn with a flame retardant property from which a garment is producible which is lightweight, comfortable to wear and has a look similar to the look of a garment without a flame retardant property.
This problem is solved by a garment according to claim 1 from which a fabric according to claim 14 is producible. The yarn can be produced according to the method of claim 13.
A yarn for producing a fabric comprises first synthetic fibers and/or third synthetic fibers. The yarn also comprises second synthetic fibers and regenerated cellulose fibers. The first synthetic fibers, the second synthetic fibers and the regenerated cellulose fibers are different types of fibers. The first synthetic fibers have a first flame retardant property, wherein the first flame retardant property is an inherent property of the first synthetic fibers. The second synthetic fibers have a second flame retardant property, wherein the second flame retardant property is an inherent property of the second synthetic fibers. The yarn being suitable for producing a fabric with an area related mass of at most 14 ounces per square yard (475 grams per square meter) and with a flame retardant property.
The terms "flame retardant", "flame resistant, "fire retardant" and "fire resistant" are used interchangeably herein. These terms relate to fabrics that resist burning, retard burning, show a self-extinguishing effect, show increased heat resistance, show reduced heat transmission and/or show increased resistance to molten metal under certain conditions. For example, these properties can be defined by passing the tests according to ISO 17493:2000, EN ISO 15025:2016 (Method A), EN ISO 15025:2016 (Method B), EN ISO 9151:2016, EN ISO 6942:2002 (Method B), ISO 12127-1:2015, and/or ISO 9150:1988, preferably each in conjunction with the requisites of EN ISO 11611:2015, EN ISO 11612:2015, and/or EN ISO 14116:2015.
The yarn may be structured such that a fabric with a flame retardant property is producible from the yarn, wherein the area related mass of the fabric is at most 12 ounces per square yard (407 grams per square meter).
It is preferred that the yarn is structured such that a fabric with a flame retardant property is producible from the yarn, wherein the area related mass of the fabric is at most 10 ounces per square yard (339 grams per square meter).
The yarn can comprise third synthetic fibers, additionally to first synthetic fibers and regenerated cellulose fibers or substituting the first synthetic fibers. The third synthetic fibers can be a different type of fibers than any one the type of the first synthetic fibers, the second synthetic fibers and the regenerated cellulose fibers.
The yarn can also comprise fourth synthetic fibers which can be different type of fibers than any one the type of the first synthetic fibers, the second synthetic fibers, the third synthetic fibers and the regenerated cellulose fibers.
The first synthetic fibers can comprise a polymer of which acrylonitrile is a monomer in the polymerization of the polymer.
Especially, the first synthetic fibers can comprise a copolymer. The copolymer can be a bipolymer. Acrylonitrile can be a monomer in the polymerization of the copolymer and a second monomer as another monomer in the polymerization of the copolymer can be selected from the group consisting of vinyl chloride, vinylidene chloride, vinyl bromide and mixtures thereof.
First synthetic fibers can be modacrylic fibers. Preferably the content of acrylonitrile in the first synthetic fibers is at least 35 wt.-%, more preferably at most 85 wt.-%, based on the total weight of first synthetic fibers.
The yarn can comprise the first synthetic fibers by between 30 wt.-% and 60 wt.-%. Preferably the yarn comprises the first synthetic fibers between 35 wt.-% and 55 wt.-%. Especially, the yarn can comprise the first synthetic fibers between 40 wt.-% and 50 wt.-%. The total weight of all fibers in the yarn is the reference value, i.e. the respective proportional weight is based on the total weight of all fibers of the yarn.
The second synthetic fibers can comprise a polyamide. Especially, the second synthetic fibers can comprise an aramid. It is preferred that the second synthetic fibers comprise a para-aramid.
The second synthetic fibers can be comprised by the yarn by at most 25 wt.-%. The yarn can also comprise between 3 wt.-% and 20 wt.-% of the second synthetic fibers. It is preferred that the yarn comprises between 7 wt.-% and 15 wt.-% of the second synthetic fibers. Again, the respective proportional weight is based on the total weight of all fibers of the yarn.
The regenerated cellulose fibers can be at least partially derived from a portion of a jute plant (jute).
Regenerated cellulose fibers are usually considered semi-synthetic fibers as these fibers are manufactured from cellulose that is derived from plants. Synthetic fibers as described above are considered as "totally" or "fully" synthetic fibers often being made from crudes and intermediates.
The yarn can comprise between 15 wt.-% and 45 wt.-% regenerated cellulose fibers. Preferably, the yarn comprises between 20 wt.-% and 40 wt.-% regenerated cellulose fibers. It is especially preferred that the yarn comprises between 25 wt.-% and 35 wt.-% regenerated cellulose fibers, wherein the proportional weight is based on the total weight of all fibers of the yarn.
Third synthetic fibers can be comprised by the yarn, instead of first synthetic fibers or additionally to first synthetic fibers.
The third synthetic fibers can comprise a polyamide. Especially the third synthetic fibers comprise a polyamide 6.6 or polyamide 6. Among polyamides for the third synthetic fibers polyamide 6.6 is especially preferred.
The yarn can comprise the third synthetic fibers by at most 30 wt.-%. Preferably, the yarn comprises the third synthetic fibers between 5 wt.-% and 25 wt.-%. It is especially preferred that the yarn comprises between 10 wt.-% and 20 wt.-%, wherein the proportional weight is based on the total weight of all fibers of the yarn.
Fourth synthetic fibers can be comprised by the yarn.
The fourth synthetic fibers can have an anti-static property. Preferably, the fourth synthetic fibers are electrically conductive fibers.
Especially, carbon modified (reinforced) polyamide 6 fibers can be used. Polyamide 6 can be the matrix polymer with carbon particles or fibers as conductive particles or fibers within the matrix polymer.
Fourth synthetic fibers can have a carbon content between 5 wt.-% and 50 wt.-%, especially between 10 wt.-% and 40 wt.-%, based on the total weight of fourth synthetic fibers.
The yarn can comprise at most 15 wt.-% of fourth synthetic fibers. The yarn can also comprise at most 10 wt.-% of fourth synthetic fibers. Especially, the yarn comprises between 1 wt.-% and 4 wt.-% of fourth synthetic fibers. The proportional weight is based on the total weight of all fibers of the yarn.
The disclosed yarn can be produced by ring spinning. First, second, third, fourth and/or regenerated cellulose fibers can be provided in a first step. In a second step the fibers are ring spun, thereby providing the yarn.
A fabric can be produced from the herein disclosed yarn, e.g. a woven fabric. The fabric comprises the yarn.
The yarn can be present in the fabric by at least 50 wt.-% of the total weight of the sum of all yarns in the fabric. Preferably the fabric comprises at least 90 wt.-% of the yarn, based on the sum of all yarns in the fabric.
It is especially preferred that the fabric comprises the same yarn for warp and weft.
The fabric can be a 3/1, a 2/1 or a 2/2 woven fabric.
Especially, the fabric is a denim fabric. Preferably, one of warp or weft is dyed with indigo and the other one is white.
The yarn and the fabric can comprise additional components, which are selected from the group consisting of bleaching agents, anti-oxidants, pigments, dyes, UV-stabilizers, antimicrobial agents, and mixtures thereof.
Embodiments of the invention are described in more detail with regard to the drawings. The description of the embodiments is not to be construed as to limit the scope defined by the claims. Like reference signs of the figures describe like elements.

Figure 1: depicts fibers 1, 2, 3, 4, 5 used for producing a yarn 10 in an embodiment.
Figure 2: depicts a yarn 10 in an embodiment.
Figure 3: depicts a fabric 30 in an embodiment.

Figure 1 schematically shows a yarn having first synthetic fibers 1, second synthetic fibers 2, regenerated cellulose fibers 3, third synthetic fibers 4, and fourth synthetic fibers 5.
Figure 2 shows the yarn 10 of Figure 1 in a cross-section.
Typically, the yarn 10 is produced by providing the fibers, e.g. first synthetic fibers 1, second synthetic fibers 2, regenerated cellulose fibers 3, third synthetic fibers 4, and fourth synthetic fibers 5, and using ring spinning. Other production methods may be used.
The yarn may pass through a rope dyeing process as known in the art.
A fabric can be produced by weaving, e.g. by using the dyed yarn for warp and an undyed yarn of the same fiber composition for weft. Thereby, a fabric is producible from the disclosed yarn.
The fabric can be coated with a transparent resin for improvement of the wet and dry rubbing fastness properties of the fabric.
The fabric is preferably woven as 3/1 right hand twill.
Fabrics are producible from the yarn having a combination of conflicting properties. The fabric has a low weight, i.e. at most 14 ounces per square yard (475 grams per square meter) or even at most 12 or 10 ounces per square yard (407 or 339 grams per square meter), and at the same time excellent safety related properties, as will be shown below.
A fabric 30 produced from the yarn 10 shown in Figures 1 and 2 is presented in Figure 3.
Garments can be produced from the fabric with excellent wear properties due to the softness of the fabric.
Such garments include e.g. trousers, shirts, gloves, and jackets.

Composition examples

An especially suitable yarn can have the following composition as example 1, wherein weight percentages are based on the total weight of the composition:

40 to 50 wt.-%	of modacrylic fibers (e.g. Dynel® or Verel®),
7 to 15 wt.-%	of para-amid fibers (e.g. Kevlar® or Twaron®),
25 to 35 wt.-%	of regenerated cellulose fibers (e.g. Rayon, Modal, or Lyocell),
10 to 20 wt.-%	of nylon 6.6 fibers,
1 to 4 wt.-%	of polyamide 6 fibers which are modified with carbon (e.g. Makamid® or UPA®).

Tests and results

In a specific example 2 a yarn comprises:

43 wt.-%	of modacrylic fibers,
11 wt.-%	of para-amid fibers,
29 wt.-%	of regenerated cellulose fibers,
15 wt.-%	of nylon 6.6 fibers,
2 wt.-%	of polyamide 6 fibers which are modified with carbon.

The respective fibers were provided in the respective weight ratios and the yarn was produced using ring spinning. From the yarn a denim fabric was woven using the (same) yarn for warp and weft. The denim fabric had an area related mass of 10 ounces per square yard (0.339 kg/m²) and was tested (pre-treated and/or non-pre-treated) as described below, wherein the properties described with reference to example 2 of the fabric are achieved by the compositions of example 1 as well, when being used to produce a denim fabric.

Breaking strength

Breaking strength was determined according to EN 13934-1:2013. The denim fabric was pre-treated in accordance with ISO 6330:2012 (temperature: 40 °C, 5 cycles method 4N and F drying.) An INSTRON dynamometer was used. The gauge length was 200 m. The rate of extension of warp and weft was 100 mm/min. The pretension for warp and weft was 5 N.
The pre-treated denim fabric showed a warp tensile strength of 1500 N as average value based on five measurements (minimum value 1400 N). The weft (fill) tensile strength was determined as average value of 1000 N based on five measurements (minimum value 960 N). The denim fabric passed the test as described in EN 13934-1:2013 with the rating "Performance Level A1" according to the requisite of EN ISO 11611:2015, EN ISO 11612:2015 and IEC 61482-2:2009.

Tear resistance

The tear resistance of the denim fabric was measured according to EN 13937-2:2000 after pre-treatment according to ISO 6330:2012 (temperature: 40 °C, 5 cycles, method 4N and F drying). An INSTRON dynamometer was used.
The pre-treated denim fabric showed a warp tear strength of 56 N and a weft (fill) tear strength of 52 N. The pre-treated denim fabric passed the requisite of EN ISO 11611:2015, EN ISO 11612:2015 and IEC 61482-2:2009.

Resistance against small molten metal splashes

A resistance of the fabric against small molten metal splashes was tested according to ISO 9150:1988. For the testing, the fabric was pre-treated according to ISO 6330:2012 (temperature: 40 °C, 5 cycles, method 4N and F drying).
The fabric showed a classification value of 22 drops and an average value of 23 (average of ten measurements), thereby meeting the requisite of EN ISO 11611:2015, point 6.8 for a class 1 rating.

Flame spread

For the determination of flame spread properties, the fabric was tested according to EN ISO 15025:2016 (Method A) using a 13008IE12 equipment. Propane was used as gas. The outer surface of the fabric was exposed to the flame.

Results of un-pre-treated fabric are shown in table 1.

Table 1

Specimen	1	2	3	4	5	6
Direction	Warp			Weft
Flaming to top or either side edge	No	No	No	No	No	No
Afterflame time [s]	0	0	0	0	0	0
Afterglow time [s]	0	0	0	0	0	0
Loose waste	No	No	No	No	No	No
Inflammation of the filter paper detached from waste	No	No	No	No	No	No
Hole formation	No	No	No	No	No	No

Results of pre-treated (ISO 6330:2012, temperature: 40 °C, 5 cycles, method 4N and F drying) fabric are shown in table 2.

Table 2

The performance level of the tested fabric is A1 according to EN ISO11611:2015, A1 according to EN ISO 11612:2015, Index 3 according to EN ISO 14116:2015, and Index 3 according to EN ISO 14116:2015 modified according to IEC 61482-2:2009.

Flame spread

For additional determination of flame spread properties, the fabric was tested according to EN ISO 15025:2016 (Method B) using a 13008IE12 equipment. Propane was used as gas. The edge (hemmed fabric specimen) was exposed to the flame.

Results of un-pre-treated fabric are shown in table 3.

Table 3

Specimen	1	2	3	4	5	6
Direction	Warp			Weft
Flaming to top or either side edge	No	No	No	No	No	No
Afterflame time [s]	0	0	0	0	0	0
Afterglow time [s]	0	0	0	0	0	0
Loose waste	No	No	No	No	No	No
Inflammation of the filter paper detached from waste	No	No	No	No	No	No

Results of pre-treated (ISO 6330:2012, temperature: 40 °C, 5 cycles, method 4N and F drying) fabric are shown in table 4.

Table 4

The performance level of the tested fabric is A2 according to EN ISO11611:2015 and A2 according to EN ISO 11612:2015.

Vertical electric resistance

Vertical electric resistance of the fabric was tested according to EN 1149-2:1997. The fabric was conditioned according to EN ISO 11611:2015. The radius of the inner electrode was 50.4 mm, the inner radius of the outer electrode was 69.2 mm, and the outer radius of the outer electrode was 89.0 mm. The contact pressure was 2.25 kPa, the applied potential was 100 V, and the current was measured after 15 s.
The test specimens were pre-treated according to ISO 6330:2012 (temperature: 40 °C, 5 cycles, method 4N and F drying) prior to measurements.
The fabric shows a classification value of 1.72 - 10⁶ Ω and an average value of 2.16 - 10⁶ Ω based on 5 measurements. According to EN ISO 11611:2015 the fabric is rated "Pass".

Dimensional change after domestic laundering

The dimensional change after domestic laundering was measured according to ISO 6330:2012 and ISO 5077:2008.
The fabric was pre-treated according to ISO 6330:2012 using a 4N washing procedure, 5 cycles, a temperature of 40 °C, and a F drying procedure (tumble dryer). A Wascator type A horizontal rum with front loading was used. A 13337E12 as equipment was used. The detergent was 98 ECE reference detergent. A Type III - 100 % polyester counterweight was used. The drying type was A3.
For preparation, marking and measuring of fabric specimens the procedure described in EN ISO 3759:2011 was used.
The dimensional change was determined according to EN ISO 5077:2008 as an average value of -2.5 % for warp and as an average value of -1.0 % for weft. Each average value is based on two measurements for independent specimens. Negative values indicate shrinkage.
Thus, in accordance with EN ISO 11612:2015, point 6.4, the fabric is rated "Pass".

Heat resistance

Heat resistance of the denim fabric was determined according to ISO 17493:2000. An air stove was used, a temperature of 180 °C was applied, and the test specimens were tested for 5 min. The fabric was pre-treated (ISO 6330:2012, temperature: 40 °C, 5 cycles, method 4N and F drying) prior to testing.
Results are depicted in table 5. Table 5

Specimen Flame Melting Shrinkage/Elongation

1 No No Warp -2.2 %

Weft -1.4 %

2 No No Warp -2.4 %

Weft -1.9 %

3 No No Warp -2.3 %

Weft -1.7 %
Thus, the fabric passed the requisite of EN ISO 11612:2015.

Heat transmission on exposure to flame

Heat transmission on exposure to flame of the fabric was tested according to EN ISO 9151:2016. The fabric was pre-treated prior to testing the fabric (ISO 6330:2012, temperature: 40 °C, 5 cycles, method 4N and F drying).
A convective heat apparatus was used and the heat flux density was 80.68 kW/m².
The heat transfer index (HTI) as defined in ISO 9151 showed a classification value for HTI 12 of 3.5 s and an average value based on three measurements for HTI 12 of 3.6 s.
The HTI 24 classification value was 5.3 s and the HTI 24 average value, based on three measurements, was 5.4 s.
Thus, the tested pre-treated fabric shows a performance level according to EN ISO 11612:2015 of B1.

Radiant heat transfer

The radiant heat transfer of the fabric was tested according to EN ISO 6942:2002 (Method B). The fabric was pre-treated prior to testing according to ISO 6330:2012, temperature: 40 °C, 5 cycles, method 4N and F drying.
A heat flux density of 19.66 kW/m² was applied.
The radiant heat transfer index (RHTI) as defined in ISO 6942 showed a classification value for RHTI 12 of 8.1 s and an average value of 9.2 s, based on three measurements.
The RHTI 24 classification value was 14.3 s and the average value, based on three measurements, was 15.1 s.
The TF classification value was 54.0 % and the average value, based on three measurements, was 57.0 %.
Thus, the tested pre-treated fabric is rated C1 according to EN ISO 11612:2015 and rated class 1 according to EN ISO 11611:2015.

Contact heat protection

The fabric was tested with regard to contact heat protection according to ISO 12127-1:2015. The fabric was pre-treated according to ISO 6330:2012, temperature: 40 °C, 5 cycles, method 4N and F drying, prior to testing.
A threshold time classification value of 7.1 s and an average value of the threshold time of 7.2 s were measured, when applying a contact temperature of 250 °C.
According to EN ISO 11612:2015, the pre-treated fabric is rated F1.

Protective clothing for use in welding and allied processes

The above described results show that a fabric according to the invention fulfills the requisites of EN ISO 11611:2015 and can be used for production of protective clothing for use in welding and allied processes.

Protective clothing to protect against heat and flame

The above described results show that a fabric according to the invention fulfills the requisites of EN ISO 11612:2015 and can be used for production of protective clothing to protect against heat and flame.

Charge decay: Protective clothing electrostatic properties

The charge decay of the denim fabric was tested according to EN 1149-3:2004. Prior to testing the fabric was pre-treated according to ISO 6330:2012, temperature: 40 °C, 5 cycles, method 4N and F drying.
Induction charge (test method 2) was used. A potential of 1200 ±50 V in 30 µs and a measurement time of 30 s was used.
An average shielding factor of 1.00 was measured based on three measurements. The average value of the measured decay half time was smaller than 0.01 s, based on three measurements.
Thus, the fabric fulfils the requirements of EN 1149-5:2008 and EN 1149-3:2004, Method induction charging, and is rated "Pass".

EN 61482-1-2:2014 (equivalent to IEC 61482-1-2:2014) - Protective clothing against the hazards of an electric arc

The denim fabric was tested for its behavior against a thermal risk when exposed to heat energy from an electric arc according to EN 61482-1-2:2014 (equivalent to IEC 61482-1-2:2014). Prior to testing the fabric was pre-treated according to ISO 6330:2012, temperature: 40 °C, 5 cycles, method 4N and F drying.

Test conditions are summarized in table 6.

Table 6

Test conditions
Class	Class 1
Testing atmosphere	17.30 °C
Testing atmosphere	29.80 % RH
Test current I_class for class 1	4 kA ± 5 %
Calibration test curve	4123 A
Average direct exposure incident energy E_io	142.3 kJ/m²
Arc duration	500 ms ± 5 %
Average real arc duration	488.3 ms
Test voltage	400 V ± 5 %
Average real test voltage	405.2 V
Average real Arc Energy W_arc	173.3 kJ
Gap between electrodes	30 ± 1 mm
Distance between the electrodes and sample	300 ± 5 mm

Visually obtained data are presented in table 7.

Table 7

Property	Measurement	Specimen 1	Specimen 2	Specimen 3	Specimen 4
	Class	Class 1	Class 1	Class 1	Class 1
Burning time	Video	0.000 s	0.000 s	0.000 s	0.000 s
Hole formation > 5 mm	Visual	No	No	No	No
Melting through to the inner side	Visual	No	No	No	No
Embrittlement	Visual	No	No	No	No
Damage on the outside	Visual	No	No	No	No
Charring on the outside	Visual	Yes	Yes	Yes	Yes
Dripping	Visual	No	No	No	No
Shrinkage	Calculated	No	No	No	No

Table 8 shows data of the conducted tests limited at 30 s. t_i is the time at which the difference between the transmitted incident energy E_it and the Stoll energy E_iStoll is maximal.

Table 8

Class 1
Property	Specimen 1	Specimen 2	Specimen 3	Specimen 4
Transmitted incident energy E_it	61.74 kJ/m²	64.50 kJ/m²	62.29 kJ/m²	65.88 kJ/m²
Time to delta peak temperature t_max	30.00 s	30.00 s	30.00 s	30.00 s
Delta peak temperature Δ T_p	11.18 °C	11.68 °C	11.28 °C	11.94 °C
Differences AEi of the transmitted energy to the Stoll limit value at t_max	-72.92 kJ/m²	-70.16 kJ/m²	-72.37 kJ/m²	-68.78 kJ/m²
Minimum difference between the transmitted energy E_it to the Stoll energy E_iStoll in t_i	-33.31 kJ/m²	-32.10 kJ/m²	-33.86 kJ/m²	-34.86 kJ/m²
Excess of the Stoll curve by the heat curve of the transmitted incident Energy E_it(t)	No	No	No	No

Thus, the tested pre-treated fabric passes the requirements of EN 61482-1-2:2014 for class 1.

Comparative measurements

A denim fabric produced from the yarn of example 2 was compared to a commercially available denim fabric ce1 and a non-denim fabric ce2.
Denim fabric ce1 consists of cotton (100 wt.-%). The denim fabric ce1 has been treated with a flame resistant coating. The fabric ce1 has a specific weight of 10 ounces per square yard.
Fabric ce2 consists of cotton, a polyester, and a static-control. The fabric ce2 has been treated with a flame resistant coating. The fabric ce2 has a specific weight of 10.5 ounces per square yard.

Test results are reported in table 9.

Table 9

Property	Example 2	ce 1	ce 2
Abrasion (ISO 12947-2), [cycles]	50,000	25,000	25,000
Tensile strength, warp (ASTM D5034 Mod.), [kg]	110	65	65
Tensile strength, weft (ASTM D5034 Mod.), [kg]	75	40	45
Tear strength, warp (ASTM D1424 Mod.), [kg]	10.0	5.5	6.0
Tear strength, weft (ASTM D1424 Mod.), [kg]	8.5	4.0	4.5

As shown in table 9, the fabric according to the invention shows increased abrasion resistance, increased tensile strength of warp and weft, and increased tear strength of warp and weft, compared to other fabrics (ce1 and ce2).
Additional to the significantly enhanced physical properties compared to other fabrics (ce1 and ce2), the flame resistant (flame retardant) property of the fabric according to the invention will remain after multiple washing procedures, since the flame resistant property of the fabric is inherent due to the use of fibers with inherent flame resistant property for the yarn. The flame resistant property of ce1 and ce2 will decrease with an increasing number of washing cycles.
Thus, the fabric produced from the yarn surprisingly shows excellent safety related properties while being lightweight (low area related mass of the fabric) and soft. These properties qualify the fabric (produced from the yarn) for production of garments that are to be worn by workers which work under harsh environmental conditions.
Further embodiments of the invention (the number is the number of the embodiment)

1. Yarn for producing a fabric, comprising one or more of: first synthetic fibers (1), second synthetic fibers (2) and regenerated cellulose fibers (3); wherein
the first synthetic fibers (1), the second synthetic fibers (2) and the regenerated cellulose fibers (3) are different types of fibers;
optionally, the first synthetic fibers (1) having a first flame retardant property, the first flame retardant property being an inherent property of the first synthetic fibers (1);
optionally, the second synthetic fibers (2) having a second flame retardant property, the second flame retardant property being an inherent property of the second synthetic fibers (2); and
the yarn being suitable for producing a fabric with an area related mass of at most 14 ounces per square yard (475 grams per square meter), and optionally with a flame retardant property.
2. Yarn of embodiment 1, comprising third synthetic fibers (4), wherein the third synthetic fibers (4) being a different type of fibers than any one of the type of the first synthetic fibers (1), the second synthetic fibers (2) and the regenerated cellulose fibers (3).
3. Yarn of embodiment 2, wherein the yarn comprises the third synthetic fibers (4) by at most 30 wt.-% of the total weight of all fibers, preferably between 5 and 25 wt.-%, more preferably between 10 and 20 wt.-%.
4. Yarn of any one of embodiments 1 to 3, wherein the yarn comprises the first synthetic fibers (1) between 30 and 60 wt.-% of the total weight of all fibers, preferably between 35 and 55 wt.-%, more preferably between 40 and 50 wt.-%.
5. Yarn of any one of embodiments 1 to 4, wherein the yarn comprises the second synthetic fibers (2) by at most 25 wt.-% of the total weight of all fibers, preferably between 3and 20 wt.-%, more preferably between 7 and 15 wt.-%.
6. Yarn of any one of embodiments 1 to 5, wherein the first synthetic fibers (1) comprising a polymer, wherein acrylonitrile is a monomer in the polymerization of the polymer.
7. Yarn of any one of embodiments 1 to 6, wherein the first synthetic fibers (1) comprising a copolymer, preferably a bipolymer, wherein acrylonitrile is a monomer in the polymerization of the copolymer and a second monomer, selected from the group consisting of vinyl chloride, vinylidene chloride, vinyl bromide and mixtures thereof, is another monomer in the polymerization of the copolymer.
8. Yarn of any one of embodiments 1 to 7, wherein the second synthetic fibers (2) comprising a polyamide.
9. Yarn of any one of embodiments 1 to 8, wherein the second synthetic fibers (2) comprising an aramid, preferably a para-aramid.
10. Yarn of any one of embodiments 1 to 9, wherein the regenerated cellulose fibers (3) comprising being at least partially derived from jute and/or wherein the yarn comprises the regenerated cellulose fibers (3) between 15 and 45 wt.-% of the total weight of all fibers, preferably between 20 and 40 wt.-%, more preferably between 25 and 35 wt.-%.
11. Yarn of any one of embodiments 2 to 10, wherein the third synthetic fibers (4) comprising a polyamide, preferably a polyamide 6.6 or a polyamide 6, more preferably a polyamide 6.6.
12. Yarn of any one of embodiments 1 to 11, wherein the yarn comprises fourth synthetic fibers (5), preferably fibers having an anti-static property, more preferably electrically conductive fibers, most preferably polyamide 6 fibers which are modified with carbon, and/or wherein the yarn comprises the fourth synthetic fibers (5) by at most 15 wt.-% of the total weight of all fibers, preferably by at most 10 wt.-%, more preferably between 1 and 4 wt.-%.
13. Method of producing a yarn of any one of embodiments 1 to 12, using ring spinning.
14. Fabric, comprising the yarn of any one of embodiments 1 to 12, preferably the fabric comprises the same yarn for warp and weft.
15. Fabric according to embodiment 14, wherein the fabric being a 3/1, a 2/1 or a 2/2 fabric.
16. Fabric according to any one of embodiments 14 or 15, wherein the fabric shows a tensile strength of the warp of at least 400 N, preferably at least 800 N, measured according to EN 13934-1:2013 and/or shows a tensile strength of the weft (fill) of at least 300 N, preferably at least 600 N, measured according to EN 13934-1:2013.
17. Fabric according to any one of embodiments 14 to 16, wherein the fabric shows a warp tear strength of at least 15 N, preferably at least 30 N, measured according to EN 13937-2:2000 and/or shows a weft (fill) tear strength of at least 10 N, preferably at least 20 N, measured according to EN 13937-2:2000.
18. Fabric according to any one of embodiments 14 to 17, wherein the fabric shows a temperature increase of the back side of the fabric of 40 °C only after application of at least 15 drops, preferably 20 drops, of molten metal to the front side of the fabric as determined according to ISO 9150:1988.
19. Fabric according to any one of embodiments 14 to 18, wherein the fabric shows no flaming to top or either side edge, no hole formation in any layer of 5 mm or greater in any direction, no flaming or molten debris, an afterflame time of at most 2 s, and/or an afterglow time of at most 2 s, as determined according to EN ISO 15025:2016 (Method A).
20. Fabric according to any one of embodiments 14 to 19, wherein the fabric shows no flaming to top or either side edge, no hole formation in any layer of 5 mm or greater in any direction, no flaming or molten debris, an afterflame time of at most 2 s, and/or an afterglow time of at most 2 s, with a pre-treatment (ISO 6330:2012, temperature: 40 °C, 5 cycles, method 4N and F drying) of the fabric and as determined according to EN ISO 15025:2016 (Method A).
21. Fabric according to any one of embodiments 14 to 20, wherein the fabric shows no flaming to top or either side edge, no flaming or molten debris, an afterflame time of at most 2 s, and/or an afterglow time of at most 2 s, as determined according to EN ISO 15025:2016 (Method B).
22. Fabric according to any one of embodiments 14 to 21, wherein the fabric shows no flaming to top or either side edge, no flaming or molten debris, an afterflame time of at most 2 s, and/or an afterglow time of at most 2 s, with a pre-treatment (ISO 6330:2012, temperature: 40 °C, 5 cycles, method 4N and F drying) of the fabric and as determined according to EN ISO 15025:2016 (Method B).
23. Fabric according to any one of embodiments 14 to 22, wherein the fabric, pre-treated according to ISO 6330:2012 (temperature: 40 °C, 5 cycles, method 4N and F drying) or non-pre-treated, shows a vertical electric resistance of at least 1.0 · Ω, preferably at least 5.0 · Ω, more preferably at least 1.0 · Ω, as determined according to EN 1149-2:1997.
24. Fabric according to any one of embodiments 14 to 23, wherein the fabric shows a dimensional change of less than ±3 % in warp and/or weft direction as determined according to EN ISO 5077:2008, wherein the fabric is pre-treated according to ISO 6330:2012 (temperature: 40 °C, 5 cycles, method 4N and F drying).
25. Fabric according to any one of embodiments 14 to 24, wherein the fabric shows one or more of the following properties: no layer ignites, no layer melts, and/or no layer shrinks more than 5 %, as determined according to ISO 17493:2000.
26. Fabric according to any one of embodiments 14 to 25, wherein the fabric shows a heat transfer index 24 as defined in ISO 9151 of at least 2 s, preferably at least 4 s, more preferably at least 5 s, as determined according to EN ISO 9151:2016.
27. Fabric according to any one of embodiments 14 to 26, wherein the fabric shows a heat transfer index 12 as defined in ISO 9151 of at least 1 s, preferably at least 2 s, more preferably at least 3 s, as being determined according to EN ISO 9151:2016.
28. Fabric according to any one of embodiments 14 to 27, wherein the fabric shows a radiant heat transfer index 24 as defined in ISO 6942 of at least 7 s, preferably at least 10 s, more preferably at least 13 s, as determined according to EN ISO 6942:2002.
29. Fabric according to any one of embodiments 14 to 28, wherein the fabric shows a radiant heat transfer index 12 as defined in ISO 6942 of at least 7 s, preferably at least 8 s, as being determined according to EN ISO 6942:2002.
30. Fabric according to any one of embodiments 14 to 29, wherein the fabric shows a threshold time of at least 5 s, preferably at least 7 s, as determined according to ISO 12127-1:2015, preferably at a contact temperature of 250 °C.
31. Fabric according to any one of embodiments 14 to 30, wherein the fabric shows a decay half time that is smaller than 4 s and/or shows a shielding factor that is greater than 0.2, wherein the decay half time and the shielding factor can be determined according to EN 1149-3:2004 and/or EN 1149-5:2008, Method induction charging.
32. Fabric according to any one of embodiments 14 to 31, wherein the fabric shows a burning time of at most 5 s, no melting through to the inner side, no hole bigger than max. 5 mm in any direction in the innermost layer and/or all four pairs of values (E_it - t_max) are below corresponding Stoll values, and all four heat curves E_it(t) of transmitted energy are at any moment of time "t" of the exposure period below the Stoll curve, as determined according to EN 61482-1-2:2014.

The fabric produced from the yarn in the embodiments above shows excellent safety related properties while being lightweight (low area related mass of the fabric) and soft.
These properties qualify the fabric (produced from the yarn) for production of garments that are to be worn by workers which work under harsh environmental conditions.

Claims

Yarn for producing a fabric, comprising first synthetic fibers (1), second synthetic fibers (2) and regenerated cellulose fibers (3), wherein
(a) the first synthetic fibers (1), the second synthetic fibers (2) and the regenerated cellulose fibers (3) are different types of fibers;

(b) the first synthetic fibers (1) having a first flame retardant property, the first flame retardant property being an inherent property of the first synthetic fibers (1);

(c) the second synthetic fibers (2) having a second flame retardant property, the second flame retardant property being an inherent property of the second synthetic fibers (2); and

(d) the yarn being suitable for producing a fabric with an area related mass of at most 14 ounces per square yard (475 grams per square meter) and with a flame retardant property.
Yarn of claim 1, comprising third synthetic fibers (4), wherein the third synthetic fibers (4) being a different type of fibers than any one of the type of the first synthetic fibers (1), the second synthetic fibers (2) and the regenerated cellulose fibers (3).
Yarn of claim 2, wherein the yarn comprises the third synthetic fibers (4) by at most 30 wt.-% of the total weight of all fibers, preferably between 5 and 25 wt.-%, more preferably between 10 and 20 wt.-%.
Yarn of any one of claims 1 to 3, wherein the yarn comprises the first synthetic fibers (1) between 30 and 60 wt.-% of the total weight of all fibers, preferably between 35 and 55 wt.-%, more preferably between 40 and 50 wt.-%.
Yarn of any one of claims 1 to 4, wherein the yarn comprises the second synthetic fibers (2) by at most 25 wt.-% of the total weight of all fibers, preferably between 3and 20 wt.-%, more preferably between 7 and 15 wt.-%.
Yarn of any one of claims 1 to 5, wherein the first synthetic fibers (1) comprising a polymer, wherein acrylonitrile is a monomer in the polymerization of the polymer.
Yarn of any one of claims 1 to 6, wherein the first synthetic fibers (1) comprising a copolymer, preferably a bipolymer, wherein acrylonitrile is a monomer in the polymerization of the copolymer and a second monomer, selected from the group consisting of vinyl chloride, vinylidene chloride, vinyl bromide and mixtures thereof, is another monomer in the polymerization of the copolymer.
Yarn of any one of claims 1 to 7, wherein the second synthetic fibers (2) comprising a polyamide.
Yarn of any one of claims 1 to 8, wherein the second synthetic fibers (2) comprising an aramid, preferably a para-aramid.
Yarn of any one of claims 1 to 9, wherein the regenerated cellulose fibers (3) comprising being at least partially derived from jute and/or wherein the yarn comprises the regenerated cellulose fibers (3) between 15 and 45 wt.-% of the total weight of all fibers, preferably between 20 and 40 wt.-%, more preferably between 25 and 35 wt.-%.
Yarn of any one of claims 2 to 10, wherein the third synthetic fibers (4) comprising a polyamide, preferably a polyamide 6.6 or a polyamide 6, more preferably a polyamide 6.6.
Yarn of any one of claims 1 to 11, wherein the yarn comprises fourth synthetic fibers (5), preferably fibers having an anti-static property, more preferably electrically conductive fibers, most preferably polyamide 6 fibers which are modified with carbon, and/or wherein the yarn comprises the fourth synthetic fibers (5) by at most 15 wt.-% of the total weight of all fibers, preferably by at most 10 wt.-%, more preferably between 1 and 4 wt.-%.
Method of producing a yarn of any one of claims 1 to 12, using ring spinning.
Fabric, comprising the yarn of any one of claims 1 to 12, preferably the fabric comprises the same yarn for warp and weft.
Fabric according to claim 14, wherein the fabric being a 3/1, a 2/1 or a 2/2 fabric.