Fabric and use of the fabric in protective clothing for fire fighting

Abstract

A fabric having a core yarn having a core consisting of 100% polyamide and a sheath consisting of flame-retardant synthetic cellulose, optionally aramid, in particular para-aramid, and optionally antistatic fibers, the yarn optionally comprising in total 1% to 12% aramid, in particular para-aramid, 52% to 70% flame-retardant synthetic cellulose, 26 to 35% polyamide, and optionally up to 2% antistatic fibers. Furthermore, the use of the fabric in protective clothing for open land fire fighting and / or technical rescue is disclosed.

Description

Technical Field

[0001] This invention relates to a fabric and its application in fire-fighting protective clothing in open areas.

[0002] Such fabrics not only need to be flame-retardant, but also must have sufficient strength. In addition, they must shrink only slightly after a certain number of washing cycles and be comfortable to wear. Background Technology

[0003] Such fabrics are known from, for example, EP 2079332 A1 and US 2005 / 0025962 A1. Furthermore, EP3831992 A1 relates to a fabric having a core yarn in the warp direction, comprising a core composed entirely of polyamide and a sheath layer composed of flame-retardant synthetic cellulose and antistatic fibers. This fabric can be used in fire-fighting protective clothing. CN 109706572 B and CN109629060 B disclose a similar yarn containing polyamide and a relatively high proportion of aramid. CN 109183223 A also employs a relatively high proportion of aramid, and CN 109629056 A constitutes further prior art. Similar fabrics also include those described in EP 2534289 A2, in which the fabric is named Defender M.

[0004] The latter patent aimed to improve upon the known Defender M fabric, particularly in terms of abrasion resistance. To this end, the proportion of polyamide was increased. However, this deteriorated the fabric's ability to suppress flame spread in terms of afterglow to the point that it was unsuitable for outdoor firefighting.

[0005] Whether new or after washing, its smoldering time in the warp and weft directions is 6.7 seconds and 8 seconds respectively, which significantly exceeds the performance requirement of ≤2 seconds in the EN ISO 15384 standard.

[0006] In addition, the yarn used is conventional ring-spun yarn, i.e., tightly blended yarn. Summary of the Invention

[0007] In this context, there is a need to improve the abrasion resistance of known fabrics without causing the flame spread suppression performance to deteriorate to the point that the fabric no longer meets the "open area fire protection" standard.

[0008] This objective is achieved by the fabric described in claim 1 of the patent.

[0009] Accordingly, the fabric comprises a core yarn whose core is composed of 100% polyamide. The sheath comprises flame-retardant synthetic cellulose, aramid (especially para-aramid), and optional antistatic fibers. The total yarn composition includes 1%-12% aramid (especially para-aramid), 52%-70% flame-retardant synthetic cellulose, 26-35% polyamide, and optionally up to 2% antistatic fibers. The strength is essentially guaranteed by the polyamide (especially PA 6.6) in the core, which can be constructed, for example, as a multifilament. Therefore, the proportion of (para-aramid) as the load-bearing material can be reduced, which has a favorable impact on manufacturing costs. It should be noted that the aramid used preferably accounts for at least 4% of the total, and / or can be para-aramid and / or meta-aramid; however, the yarn may be particularly free of meta-aramid. The polyamide in the core is also preferably present in the form of a high-strength and shrunken filament yarn. Because of the use of core / sheath yarns containing polyamide, the proportion of polyamide can be set significantly higher than that in EP 2534289 A2 without worsening the flame spread.

[0010] Due to this yarn structure, the yarn, and especially the fabrics made from it, have inherent flame retardancy, which is cost-effective and beneficial as it eliminates the need for flame-retardant finishing of the fabric.

[0011] At the same time, fabrics made from the aforementioned yarn offer relatively comfortable wear because the sheath is primarily composed of synthetic cellulose, which advantageously exhibits good moisture absorption. Furthermore, this material also boasts excellent dyeability and printability.

[0012] Due to its specific construction, the fabric according to the invention retains its textile properties even when heated. Even after prolonged (5 minutes) exposure to high temperatures (260°C), it does not become brittle, retains its material flexibility, and thus meets the requirements of EN ISO 15384 as tested according to EN ISO 17493. In contrast, fabrics with, for example, a PES core (with a sheath having the same composition as described herein) become brittle and "crush."

[0013] The sheath can be spun around the core and then twisted. Furthermore, when the fabric is exposed to flame, the sheath ensures that the polyamide in the core is protected, preventing it from burning, smoldering, melting, or producing molten particles. Therefore, a polyamide content of up to 35% can be achieved, which is beneficial for strength and avoids the aforementioned potential problems.

[0014] The (para)aramid fibers in the sheath also have a positive effect, namely reducing heat transfer caused by radiation. Kevlar, Twaron, and others can be used as para aramid fibers. Therefore, para aramid fibers are used as heat insulation and barrier layers when exposed to flames; in other words, the fabric will not "disintegrate".

[0015] In summary, the strength properties are concentrated in the core, while the favorable properties for wearing comfort and printability are concentrated in the sheath. Furthermore, it meets the aforementioned requirements for outdoor firefighting, and this new fabric is relatively inexpensive.

[0016] Preferred embodiments are further described in the claims.

[0017] Advantageously, in terms of wearing comfort, it is preferable that the sheath (i.e. the outer surface of the yarn) contains at least 83%, and particularly at least 91%, flame-retardant synthetic cellulose, i.e., flame-retardant viscose fiber.

[0018] Advantageously, the fabrics made of the aforementioned yarns according to the invention have a warp strength of 900 to 1100 N / 5 cm, particularly at least 1000 N / 5 cm, and / or a maximum weft tensile strength of 800-1000 N / 5 cm, particularly at least 900 N / 5 cm, according to ASTM D 5034 or EN ISO 13934-1. Thus, the specified strengths can be achieved.

[0019] Furthermore, tear resistance and expansion resistance are improved by employing tear-resistant weaving.

[0020] Preferably, the tear resistance in the warp and / or weft directions is at least 50 N, according to ASTM D 2261 or EN ISO 13937-2.

[0021] Meanwhile, according to EN 12127, the weight of the fabric can be kept at a relatively low 180-200 g / m², especially about 190 g / m².

[0022] This also applies to a 2% change in warp and / or weft dimensions after five household washing cycles according to AATCC 135 or EN ISO 5077 / 6330.

[0023] As previously stated, the fabrics produced according to this invention meet the requirements of EN ISO 15384 standard, tested according to EN ISO 15025 Methods A and B. In other words, the smoldering time and afterflame time are at most 2 seconds. No sample should exhibit burning or molten particle shedding. Furthermore, no sample should have holes of 5 mm or more in any direction.

[0024] Regarding the heat transfer values ​​measured using method B = 20 kW / m² according to EN ISO 6942:2002, whether new or after washing, the RHTI24 value (i.e., a back-side temperature rise of 24 K (K = Kelvin)) is reached only after 13 seconds, and in all cases exceeds 11 seconds. A back-side temperature rise of 12 K, i.e., RHTI12, occurs after at least 6 seconds, and in all cases exceeds 4 seconds, with an average air permeability of less than 55%, and a maximum of 70% in all cases. Therefore, the fabric according to the invention advantageously achieves the target values ​​according to EN ISO 15384:2022.

[0025] According to EN ISO 12947-2, the abrasion resistance under a 12 kPa load is also very high, i.e., at least 140,000 cycles, while the abrasion resistance of similar fabrics used for fire-fighting protective clothing in open areas is about 60,000 cycles.

[0026] In general, the fabrics produced according to the present invention advantageously provide protective clothing for firefighting in open areas, thus conforming to EN ISO 15384. This also conforms to EN 16689:2017. These standards also specify specific color values ​​and lightness factors after exposure, thereby achieving high visibility conforming to EN ISO 20471. Fabrics produced according to the present invention with a reduced para-aramid content also advantageously meet these requirements in the standards.

Claims

1. A fabric having a core yarn having a core composed of 100% polyamide and a sheath composed of flame-retardant synthetic cellulose, aramid, especially para-aramid, and optionally antistatic fibers, the yarn comprising a total of 1%-12% aramid, especially para-aramid, 52%-70% flame-retardant synthetic cellulose, 26-35% polyamide, and optionally up to 2% antistatic fibers.

2. The fabric according to claim 1, Its features are, The sheath contains at least 83% flame-retardant viscose fiber as flame-retardant cellulose.

3. The fabric according to claim 1 or 2, Its features are, The sheath contains at least 91% flame-retardant viscose fiber.

4. The fabric according to any one of the preceding claims, Its features are, According to ASTM D 5034 or EN ISO 13934-1, its tensile strength in the warp direction is 900 to 1100 N / 5 cm, and / or in the weft direction is 800 to 1000 N / 5 cm.

5. The fabric according to any one of the preceding claims, Its features are, It features tear-resistant weave.

6. The fabric according to any one of the preceding claims, Its features are, According to ASTM D 2261 or EN ISO 13937-2, its tear resistance in the warp and / or weft directions is at least 50 N.

7. The fabric according to any one of the preceding claims, Its features are, Its surface weight is 180-200 g / m², especially about 190 g / m².

8. The fabric according to any one of the preceding claims, Its features are, After five household washing cycles according to AATCC 135 or EN ISO 5077 / 6330, the maximum dimensional change in the warp and / or weft directions is 2%.

9. The fabric according to any one of the preceding claims, Its features are, It meets the requirements of EN ISO 15384 standard, tested according to EN ISO 15025 Method A and Method B.

10. The fabric according to any one of the preceding claims, Its features are, Whether new or after washing, it has an RHTI24 value of at least 13 seconds, and / or an RHTI24-RHTI12 value of at least 6 seconds, and / or an average air permeability of at most 55% according to EN ISO 15384:2022.

11. The fabric according to any one of the preceding claims, Its features are, According to EN ISO 12947-2, its abrasion resistance is at least 140,000 cycles under a load of 12 kPa.

12. The use of the fabric according to any one of the preceding claims in protective clothing for firefighting and / or technical rescue in open areas.