MXPA06011102A - Fabric for protective garments - Google Patents

Abstract

This invention relates to heat and flame resistant single ply fabric for use as a single or outer layer of a protective garment for a wearer. The fabric comprises at least one warp system and at least two weft systems. The warp system comprises a blend of 60 to 90 wt-%poly-m-phenylenisophtalamid (meta-aramid) and 10 to 40 wt-%poly-p-phenylenterephtalamid (para-aramid). The first of the at least two weft systems comprises a blend of 85 to 95-wt%meta-aramid and 5 to 15 wt-%para-aramid. The second of the at least two weft systems essentially comprises para-aramid.

Description

FABRIC FOR PROTECTIVE DRESS CLOTHES FIELD OF THE INVENTION The invention is concerned with a heat resistant fabric and flame for use as a single layer or outer layer of protective garments.; '' ' BACKGROUND OF THE INVENTION A garment that protects against heat and flame is also known as "waterproof clothing" and is usually used as a uniform to identify, for example, a fire fighter. Such a garment is usually quite heavy due to the mass and thickness of the garment itself if normally, the main factors that confer protection. "Consequently, the user of such garment is limited in his movements and suffers. thermal stress of such '' "4-W so that the comfort of global use decreases sharply. In the past 20 years, attempts have continually been made to develop new materials in order to improve the comfort of wearing such protective garments. For example, lightweight but more bulky insulation materials have been developed for this purpose. These materials impart more lightness to the final protective garment but could affect the user's respiratory activities due to their annoying dimensions. In addition, the freedom of movement is not necessarily improved by using these yy Reí .: 175475 '^ materials. Garments that protect against heat and flame are usually made of one or more layers. The choice of the different materials and the number of layers that constitute the final protective garment depend on the specific application of the garment itself. When designing a new protective garment, care must be taken that all the criteria of the relevant national and international standards are met. As an example, clothing resistant to heat and flame should be manufactured in accordance with EN-340, EN-531, EN 469 also as NFPA 1971: 2000, NFPA 2112: 2001 and NFPA 70E-2000. For example, a lighter protective garment could be manufactured by simply using lighter materials. However, this is usually associated with a decrease in the mechanical and thermal properties of the protective garment. In addition, attire raincoats are usually worn by most fire brigades for an average period of 5 years and therefore, are expected to fully maintain their performance in terms of heat and flame resistance, also as in terms of its aesthetic appearance, during such a period of time. WO 00/066823 discloses a fire resistant textile material comprising a woven front fabric which may include poly-m-phenylene isophthalamide (meta-aramid) fibers, the fabric includes a woven mesh of low thermal shrinkage fibers. WO 02/079555 discloses a reinforced fabric comprising a base fabric having on its rear surface a reinforced grid consisting of warp and weft yarns produced in a material having higher mechanical properties than those which produce the yarns of the base fabric . In such a reinforced fabric, the reinforced grid is bonded to the base fabric by its warp and weft yarns which are fixed on the base fabric at different points and intersecting each other to the outside of the base fabric. The products developed under the two prior art documents mentioned above increase the mechanical and thermal performance of the single layer structures. However, by adding such a reinforcing grid to the back side of the single layer, the fabric according to these prior art documents is converted into a semi-dyed woven structure in such a way that its specific weights are necessarily higher than those of the fabrics strictly single layer. The problem at the root of the present invention is therefore to provide a single-layer fabric resistant to heat and flame which maintains its performance and aesthetic appearance over the years and which, if used as one or only one outer layer of protective clothing, allows to increase the comfort of use and improve the dissipation of steam and heat produced by the user.

BRIEF DESCRIPTION OF THE INVENTION Now, it has surprisingly been found that the above-mentioned problems can be overcome by a single-layer heat-resistant fabric and flame for use as a single layer or outer layer of a protective garment for a user, characterized in that at least one warp system and at least two weft systems, the warp system comprises a combination of 60 to 90% by weight of poly-m-phenylene isophthalamide (meta-aramid) and 10 to 40 % by weight of poly-p-phenyleneterephthalamide (para-aramid), the first of the at least two screen systems comprises a combination of 85 to 95% by weight of meta-aramid and 5 to 15% by weight of para-aramid. Aramid, the second of the at least two weft systems essentially comprise para-aramid and characterized in that the fabric is woven such that from about 55% by weight to about 80% by weight of the warp system appears on the side of cloth facing the user, from about 55% by weight to about 80% by weight of the first of the at least two screen systems appears on the side of the fabric facing away from the wearer and about 70% by weight at about 90% by weight of the second of the at least two weft systems appear on the side of the fabric facing the wearer. X. Another aspect of the present invention is a garment for protection against heat and flame comprising the above fabric as a single layer or outer layer, -f. - The garment according to the present invention strongly improves the comfort of the user both é? normal situations as in critical situations. It is lighter and thinner than conventional garments that have similar mechanical and thermal properties and allows a higher heat and vapor dissipation from the user's surface to the environment.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a schematic representation of the fabric representation of a fabric according to the present invention (example 1). Figure 2 is a schematic representation of the tissue construction of a comparative fabric (example 2). • X & and DETAILED DESCRIPTION OF THE INVENTION Due to its peculiar structure, the fabric according to the present invention can have a specific weight that is lower than that of conventional fabrics having comparable mechanical and thermal properties when used as a single layer or layer. external of a protective garment. The fabric of the present invention has particularly good mechanical properties due to the structure of its weft system consisting of an alternating sequence of yarns including a substantial amount of meta-aramid fibers and yarns comprising essentially para-aramid fibers. The particular fabric structure, according to which the fabric side facing the wearer includes more para-aramid fibers than the fabric side facing away from the wearer, allows to confer to the fabric according to the present invention thermal protection and aesthetic appearance optimized over time. The optimum amount and distribution of the meta-aramid and para-aramid fibers on all two sides of the fabric according to the present invention depend on the specific applications and the materials used. Generally speaking, the larger the amount of para-aramid fibers, the better the physical performance and resistance of the fabric itself to the open rupture during thermal exposure. On the other hand, too high a concentration of para-aramid fibers in the fabric affects its flexibility and aesthetic appearance. Preferably, the para-aramid fabrics constitute about 15 to about 30% by weight of the overall weight of the fabric.

In addition, the fabric according to the present invention can be manufactured under standard process conditions by using conventional machines for weaving single layer structures, thus making its production easier and more efficient in cost. Aramid materials suitable for the manufacture of the fabric according to the present invention may have various physical and chemical properties according to the specific use of the fabric. Suitable meta-aramid and paraaramide materials are for example commercially available under the trademarks NOMEX® and KEVLAR®, respectively, from E.I. du Pont de Nemours and Company, Wilmington, Delaware, United States of America. According to a preferred embodiment of the present invention, the ratio between the first and the second of the at least two raster systems is chosen in such a way that the ratio in total weight percent between meta-aramid and para-aramid in the at least two weft systems it is substantially the same as the proportion in weight percent of meta-aramid and para-aramid in the warp system. The term "substantially the same" means that the discrepancy between the values of the meta / para-aramid weight percent ratio of the warp and weft systems may not exceed approximately 30% of the value of either the proportion in weight percent meta / para-aramid of the warp or weft system. Advantageously, such a discrepancy can not exceed approximately 20% of the value of either one or the other of the meta / para-aramid weight percent ratio of the warp or weft system. According to a preferred embodiment of the present invention, the warp and weft systems of the fabric are, independently of one another, based on filaments, individual yarns and braided yarns. "Filament" means manufactured fibers that are extruded into filaments that are eventually converted into filament yarns. Advantageously, the warp and weft systems of the fabric according to the present invention are made of braided yarns. The linear mass of the yarns forming the warp and weft systems depends on the specific use of the fabric. Linear mass values are commonly between about 200 and about 500 dtex. According to another preferred embodiment of the present invention, the fibers constituting the first of the at least two raster systems have a linear mass. from about 1.1 to about 1.4 dtex, the fibers that make up the second of the at least two weft systems have a linear mass of about 1.7 to about 2.4 dtex and the fibers that make up the warp system have a linear mass value of approximately 1.7 to approximately 2.2 dtex. Such a difference in the linear mass of the fibers that make up the warp and weft systems is mainly due to the fact that the finer the fibers the better the thermal insulation they provide, so that the finer fibers will be used advantageously to the first of the at least two raster systems, such a raster system appears predominantly on the side of the fabric facing away from the user. Thus, in order to further increase the insulation effect of the fabric, particularly for exposures to heat and flames of up to three (3) seconds, the linear mass values of the fibers constituting the screen systems will preferably be lower than those of the fibers constituting the warp system and the weft systems will appear more predominantly on the side of the fabric facing away from the wearer. Preferably, the fabric of the present invention has two weft systems and its overall specific weight commonly ranges from about 170 to about 250 g / m2, preferably from about 180 to about 220 g / m2. Advantageously, the first of the at least two weft systems and the warp system of the fabric according to the present invention each comprise up to 4% by weight of anti-static fibers. The presence of such fibers makes it possible to prevent, to dissipate or at least strongly reduce electrical charges that can be produced on the surface of the fabric. Any kind of antistatic fiber appropriate for this purpose can be used. Examples thereof are inductive fibers such as carbon fibers laminated with polyamide, semi-conductive fibers such as polyamide or polyester coated with copper or silver and conductive fibers such as steel fibers. A second aspect of the present invention is a garment for protection against heat and flames comprising a structure made of at least one layer of the fabric described above. According to a preferred embodiment of the present invention, the garment comprises a structure comprising an inner layer, optionally an intermediate layer made of a waterproof, breathable material and an outer layer made of the fabric described above of the invention. The inner layer, which faces the body of the wearer, can be an insulating liner manufactured, for example, from a layer of two, three or more folds. The purpose of such lining is to have an additional insulating layer that additionally protects the wearer from heat. The inner layer can be made of a woven, knitted fabric, a non-woven fabric and combinations thereof. Preferably, the inner layer is made of a fabric comprising fire-resistant, non-meltable materials, such as a woven fabric quilted with a ++++ fleece made of meta-aramid. The garment according to the present invention can be manufactured in any possible way. It may include an additional inner layer made, for example, of cotton or other materials. The innermost layer is directly in contact with the user's skin or the user's underwear. The garment according to the present invention may be of any kind which includes, but is not limited to jackets, raincoats, trusses, gloves, coveralls and wraps. The invention will be further described in the following examples.

EXAMPLES Example 1 (Of the invention) A combination of fibers, commercially available from E.I. Du Pont de Nemours and Company, Wilmington, Delaware, United States of America, under the trade name Nomex® N305 having a cut length of 5 cm and consisting of: - 75% by weight of pigmented poly-metaphenylene isophthalamide staple fibers (meta-aramid) of 1.7 dtex; 23% by weight of poly-paraphenylene terephthalamide (para-aramid) fibers of 1.7 dtex; and - 2% by weight of carbon fibers laminated with polyamide (anti-static fibers); was spun by rings to a single cut yarn (Yl) using conventional cotton staple fiber processing equipment. Yl had a linear mass of Nm 55/1 or 182 dtex and a torsion of 871 turns / m (TPM) in Z direction and was subsequently treated with steam to stabilize its tendency to wrinkle. Two Yl wires were then folded and braided together. The resulting folded yarn (TY1) had a line density of Nm 55/2 or 364 dtex and a twist of 621 TPM in the S direction. The TY1 yarn was used as a warp yarn. A combination of fibers, commercially available from E.I. du Pont de Nemours and Company, Wilmington, Delaware, United States of America, under the trade name Nomex® N313, which has a cut length of 5 cm and which consists of: - 88% by weight of pigmented staple fibers of poly-metaphenylene isophthalamide (meta-aramid), 1.4 dtex; 10% by weight of poly-paraphenylene terephthalamide (para-aramid) fibers of 1.7 dtex; and - 2% by weight of carbon fibers laminated with polyamide (anti-static fibers); was spun by rings to a single cut yarn (Y2) using conventional cotton staple fiber processing equipment. Y2 had a linear mass of Nm 55/1 or 182 dtex and a torsion of 890 TPM in the Z direction and was subsequently treated with steam to stabilize its tendency to wrinkle. Two Y2 yarns were then folded and braided together. The resulting folded and braided yarn (TY2) had a linear density of Nm 55/2 or 364 dtex and a twist of 620 TPM in the S direction. The TY2 yarn was used as the weft yarn. Broken fibers stretched (100% by weight) commercially available from E.I. du Pont de Nemours and Company, Wilmington, Delaware, United States of America, under the tradename Kevlar® T970 black, were spun by rings to a single cut yarn (Y3) using a conventional worsted cut fiber processing equipment. Y3 had a linear density of Nm 50/1 or 200 dtex and a torsion of 560 TPM in the Z direction and was subsequently treated with steam to stabilize its tendency to wrinkle. Two Y3 wires were then folded and braided together. The resulting folded yarn (TY3) had a linear density of Nm 50/2 or 400 dtex and a torsion of 500 TPM in the S direction. The TY3 yarn was used as the weft yarn.

A fabric weave having a special woven plane as described in Figure 1 was prepared. This fabric had 28 threads / cm (warp) of TY1, 22 threads / cm (weft) (20 threads / cm of TY2 and 2 threads / cm of TY3) and a specific weight of 185 g / m2. The warp system appeared predominantly on the side of the fabric facing the wearer (61%), the first of the two weft systems appeared predominantly on the web side facing away from the wearer (65%) and the second raster system appeared predominantly on the cloth side facing the user (80%). The following physical tests were carried out on the fabric described in this example 1: - Determination of breaking strength and elongation in accordance with ISO 5081; - Determination of tear strength according to ISO 4674/2; - Radiant heat and convection tests combined with the thermal protection performance test (TPP) method (ISO-FDIS 17492) as a single layer with a thermal flow calibrated at 2.0 calories / cm2 / second, TPP is the factor that measures the energy in (cal / cm2) needed to simulate a second degree burn on the skin of an individual; - The fabric failure factor (FFF) which is defined as follows: FFF = 100 x TPP (cal / cm2) / weight of fabric (g / m2); The fabric described in this example 1 was tested both as a single layer ("fabric" in Tables I and II) and as the outer covering of a multilayer structure ("clothing" in Tables I and II) which also consisted of of (1) an intermediate layer of a polytetrafluoroethylene (PTFE) membrane laminated to a non-woven fabric made of 85% by weight of Nomex® and 15% of Kevlar® and has a specific gravity of 135 g / m2 (commercially available under the trade name GORE-TEX® Fireblock er N of the Company WL Gore and Associates, Delaware, United States of America) and (2) an inner layer of a meta-aramid thermal bar that has a weight of 140 g / m2 padded on a 100% by weight Nomex® N 307 fabric having a specific weight of 110 g / m2. The results are given in Table 1.

Example 2 (Comparative) A combination of fibers, commercially available from E.I. du Pont de Nemours and Company, Wilmington, Delaware, United States of America under the trade name Nomex® N305 having a cut length of 5 cm and consisting of: - 75% by weight of staple fibers of poly-metaphenylene isophthalamide (meta -aramid) pigmented of 1.7 dtex; 23% by weight of poly-paraphenylene terephthalamide (para-aramid) fibers of 1.7 dtex; and - 2% by weight of carbon fibers laminated with polyamide (anti-static fibers); was spun by rings into a single cut yarn (Yl) using a conventional cn staple fiber processing equipment. Yl had a linear mass of Nm of linear mass of Nm 55/1 or 182 dtex and a torsion of 871 turns / m (TPM) in Z direction and was subsequently treated with steam to stabilize its tendency to wrinkle. Two Yl wires were then folded and braided together. The resulting folded yarn (TYl) had a linear density of Nm 55/2 or 364 dtex and a twist of 621 TPM in the S direction. The TYl yarn was used as a warp yarn. A fabric weave having a fabric plane especially as described in Figure 2 was prepared. This fabric had 29 threads / cm (warp) of TYl, 25 threads / cm of TYl and a specific weight of 195 g / m2. The same physical tests as in example 1 were carried out on the fabric described in this example 2. The results are given in Table 1.

TABLE 1 Table 1 shows that the physical and thermal properties according to the present invention (example 1) are much better than those of the comparative fabric (example 2), although the last fabric has a higher specific weight. The fabric is in particular with respect to air permeability and its thermal protection when used as an outer covering of a garment, better values of these elements allow not only to increase protection against heat and flame, but also to increase comfort of use and the dissipation of heat and steam from the fabric. fifteen Example 3 (Comparative) A fabric structure was prepared in accordance with the teachings of prior art document WO 00/066823, which is a structure comprising a woven front fabric and a woven mesh back part of low thermal shrinkage. The front of the fabric was manufactured from a combination of fibers, commercially available from E.I. du Pont de Nemours and Company, Wilmington, Delaware, United States of America, under the trade name Nomex® N307, having a cut length of 5 cm and consisting of: - 93% by weight of pigmented staple fibers of poly-metaphenylene isophthalamide (meta-aramid) of 1.4 dtex; 5% by weight of poly-paraphenylene terephthalamide (para-aramid) fibers of 1.7 dtex; and 2% by weight of carbon fibers laminated with polyamide (anti-static fibers); such a combination of fibers was spun by rings as in example 1 to a braided cut yarn using conventional cn staple fiber processing equipment. The obtained braided cut yarn had a linear density of Nm 40/2 or 500 dtex. A woven mesh back part made of para-aramid cut yarn was woven together with the front material according to WO 00/066823.

The final composition of the fabric was 89% by weight of meta-aramid, 9% by weight of para-aramid and approximately 2% by weight of anti-static fiber. The specific weight of the fabric was 215 g / m2.

Example 4 (Comparative) A fabric structure was prepared in accordance with the teachings of the prior art document WO 02/079555, this is a reinforced fabric comprising a base fabric having on its rear surface a reinforced grid consisting of yarns of warp and weft produced from a material that has superior mechanical properties than those that produce the threads of the base fabric. In such a reinforced fabric, the reinforced grid is bonded to the base fabric by its warp and weft threads which are fixed on the base fabric at different points and intersecting each other to the outside of the base fabric. The fabric front was made from a combination of fibers, commercially available from E.I. du Pont de Nemours and Company, Wilmington, Delaware, United States United States, under the trade name Nomex® N307, having a cut length of 5 cm and consisting of: - 93% by weight of pigmented staple fibers of poly-metaphenylene isophthalamide (meta-aramid) of 1.4 dtex; - 5% by weight of poly paraphenylene terephthalamide (para-aramid) fibers of 1.7 dtex, and - 2% by weight of carbon fibers laminated with polyamide (anti-static fibers); such a combination of fibers was spun by rings as in example 1 to a braided cut yarn using conventional cotton staple fiber processing equipment. The obtained braided cut yarn had a linear density of Nm 60/2 or 333 dtex. A reinforcing grid made of para-aramid cut yarn was bonded to the base fabric by its warp and weft yarns which were fixed on the base fabric at different points and intersecting each other to the outside of the base fabric in accordance with WO 02/079555. The final composition of the fabric was 82% by weight of meta-aramid, 16% by weight of para-aramid, and about 2% by weight of anti-static fiber. The specific weight of the fabric was 220 g / m2. Table II shows the values of FFF and TPP, as well as the air permeability of the fabric according to the present invention (example 1) and of the fabrics of the comparative examples 2, 3 and 4. The values of FFF and TPP they have been obtained by testing the fabrics as the outer covering of a garment as described in Example 1, while the air permeability was tested on the fabrics as a single layer.

TABLE II Table II shows that the fabric according to the present invention has the highest FFF value among all the fabrics that have been tested, so that its performance in terms of thermal protection per unit of specific weight is not only much better than that of comparative example 2, but still much better than that of the prior art materials described in examples 3 and 4 which are semi-double-weave structures. The air permeability of the fabric of the invention is significantly higher than that of the fabric of the prior art, in such a way that the thermal stress is decreased and the comfort of the user strongly improved. Table II also shows that global protection (TPP value) of the garment having external cover the fabric according to the present invention is better than that of any other garment having as external cover the fabrics of the comparative examples 2 to 4.

This will give the user more protection than a reduced overall weight of the garment. It is noted that, in relation to this date, the best method known by the applicant to carry out the aforementioned invention is the conventional one for the manufacture of the objects to which it relates.

Claims (10)

1. CLAIMS -s éá Having described the invention as above, the claim contained in the following claims is claimed as property: "1. A single-layer heat-resistant fabric and flame for use as a single layer or outer layer of a protective garment. for a user, characterized in that it comprises at least one warp system and at least two weft systems, the warp system comprises a combination of 60 to 90% by weight of poly-m-phenylene isophthalamide (meta-aramid) and 10 to 40% by weight of poly-p-phenylene terephthalamide (para-aramid), the first of the at least two screen systems comprises a combination of 85 to 95% by weight of meta-aramid and 5 to 15% by weight of para-aramid, the second of the at least two screen systems comprises essentially para-aramid and wherein the fabric is woven in such a way that from about 55% by weight to about 80% by weight. The weight of the warp system appears on the cloth side facing the wearer, from about 55% by weight to about 80% by weight of the first of the at least two weft systems appearing on the fabric side of the fabric. far away from the user and approximately 70% by weight < - '' '- OS approximately 90% by weight of the second of the at least two screen systems appears on the side of the fabric facing the user. ß l-.
2. 2. The fabric according to claim 1, characterized in that the ratio between the first and the second of the at least two weft systems is chosen in such a way that the proportion in percent by weight between meta-aramid and for Aramid in the at least two weft systems is substantially the same as the proportion in weight percent between meta-aramid and para-aramid in the warp system.
3. 3. The fabric according to claim 1, or 2, characterized in that the warp and weft systems are independent of each other, based on individual filaments, yarns and twisted yarns .. The fabric in accordance with any of the - "- the preceding claims, characterized in that the fibers constituting the first of the at least two systems. Weft has a linear mass of about 1.1 to about 1.4, the fibers that constitute the second of the at least two raster systems they have a linear mass1 of 1.7 to about 2.
4. 4 and the fibers that make up the weft system have a linear mass of about 1.7 to about 2.2.
5. 5. The fabric according to any of the preceding claims, characterized in that the first of the at least two weft systems and the warp system each comprise up to 4% by weight of static anti-static fibers. ,: - 6.
6. The fabric according to any of the preceding claims, characterized in that the warp and weft systems are twisted yarns.
7. The fabric according to any of the preceding claims, characterized in that it has a specific weight of about 170 to about 250 g / m2. - •
8. 8. The fabric according to any of the preceding claims, characterized in that it has two weft systems.
9. 9. A garment for protection against heat and flames, characterized in that it comprises a structure made of at least one layer of a fabric according to any of claims 1 to 8.
10. 10. The garment in accordance with Claim 9, characterized in that it comprises a cap? internal, optionally an intermediate layer made of a breathable waterproof material and an outer layer made of the fabric according to any of claims 1 to 8.