Patent Application
20130212790
The present invention relates to a flame resistant fibre blend and in particular, although not exclusively, to yarns, fabrics, garments, woven, knitted, and non-woven products prepared from a flame resistant fibre blend.
Flame Resistant (FR) materials are employed in many textile applications. In particular, FR materials are used as barrier layers to protect more flammable internal components such as inner stuffing within furniture including mattresses, sofas and the like. FR materials are also used to make FR clothing used in specific industrial applications and the military.
First generation fire resistant materials, particularly for the construction of garments to be worn, were based on natural fibres, including in particular wool and cotton. The flame retardant functionality was provided by chemically treating the natural yarns with phosphorous based flame retardant chemicals. The resultant garments, whilst being resistant to flames were however disadvantageous for a number of reasons. In particular, these early FR garments were uncomfortable to wear for reasonable periods as they were typically heavy with the wearer becoming increasingly hot. More recently, synthetic FR blends have been developed with a view to providing lighter more breathable garments so as to increase comfort.
US 2008/0145543 discloses a high performance FR textile fabric for use in producing close fitting garments, such as undergarments, in direct contact with the skin. The fabric is formed from yarns of rayon filaments, and a cured phosphorous-based flame retardant compound is affixed to the filaments and imparts further flame retardant properties to the fabric.
US 2005/0204718 discloses a blended yarn designed to provide arc and flame protective properties. The yarn is manufactured from 40% to 70% by weigh of a modacrylic, 5% to 20% by weight of p-aramid and 10% to 40% by weight of m-aramid. The entirely synthetic material is designed to achieve a tensile strength sufficient to be resistant to ‘break-open’ when exposed to an electric arc.
WO 2008/027454 discloses flame resistant fabrics comprising a blend of a synthetic cellulosic and a FR modacrylic. Garments produced from the fibres are designed to be resistant to electric arc flash and flames.
However, whilst these more recent synthetic FR textiles perform better than the earlier natural fibre based garments there are a number of disadvantages. Firstly, entirely synthetic FR garments are expensive for a number of reasons. The component fibres are typically only available from specialist manufacturers resulting in limited availability. Secondly, the manufacture of these component fibres is complex, requiring a variety of chemical processing steps. Thirdly, FR textiles made entirely from synthetic fibres are typically uncomfortable for the wearer due, in part, to their poor softness and breathability characteristics.
There is therefore a need for a flame retardant fibre blend that may be conveniently and efficiently mass produced for the manufacture of FR garments that satisfy the required national and/or international safety standards whilst being comfortable for the wearer.
Accordingly, the inventors provide a fibre blend that is designed to be breathable, soft and provide moisture management characteristics. The present fibre blend is also configured to be multipurpose being suitable for use as a safety garment that offers a protective function within a variety of very different hazardous environments. Utilising natural materials further provides for a cost effective solution to the problem of increasing the FR of a textile.
For example, fabrics manufactured from the present fibre blend are configured to satisfy a variety of different safety standards including in particular, flame retardance protection against radiant and convective heat; electric arc; contact heat and protection against the effects of a hydrocarbon flash fire.
The present fibre blend comprises both synthetic and natural fibres. In particular, a natural cellulosic material is employed to provide a garment that is comfortable for the wearer due, in part, to the breathability and softness. The moisture management characteristics of the resulting textiles are also enhanced due primarily to the ‘wicking’ characteristics resultant from the synergistic combination of the natural and synthetic materials.
The present blend is specifically configured to be blended and spun to form a yarn having a composite structure formed from the fibre blend.
According to a first aspect of the present invention there is provided a flame retardant yarn having a composite structure formed from a collection of fibres twisted together, the fibres comprising a blend of:
The term modacrylic fibre refers to a modified version of acrylonitrile which is resultant from the copolymerisation of acrylonitrile with another compound. The copolymer may comprise 30% to 70% by weight of acrylonitrile and 70% to 30% by weight of a halogen-containing vinyl monomer. The halogen-containing vinyl monomer is preferably at least one monomer selected from vinyl chloride or vinylidene chloride.
Preferably, the modacrylic fibres are copolymers of acrylonitrile combined with vinylidene chloride, the copolymer further comprising at least one type of antimony oxide for improved fire retardancy. In particular, antimony trioxide and/or pentoxide may be used to dope the resultant copolymer. Accordingly, the flame retardant, physical and mechanical properties of the fibre blend may be tailored by, in particular, variation of the type and quantity of the antimony oxide added.
According to specific implementations, the modacrylic fibre of the present invention comprises the fibres disclosed in U.S. Pat. No. 3,193,602; U.S. Pat. No. 3,748,302; U.S. Pat. No. 5,208,105 and U.S. Pat. No. 5,506,042, the contents of which are incorporated by reference herein.
The preferred modacrylic fibres of the present invention are fibres based on Kanecaron™ (available from Kaneka Corporation, Kanecaron Division, 3-2-4, Nakanoshima, Kita-ku, Osaka 530-8288, Japan). Reference to Kanecaron™ includes Kanekaron™ and Kanekalon™.
More preferably, the present fibre blend may comprise any one or a combination of different grades of Protex™ selected from: Protex™ W; Protex™ M; Protex™ T; Protex and/or other modacrylic FR materials falling within the Protex™ family and available from Kaneka.
Preferably, the modacrylic comprises Protex Q™. Optionally, the modacrylic may comprise Sevel™ (available from Fushun Huifu Fire Resistant Fibre Co Limited, No 54, West Section Anshan Road, Fushun City, Conn.-113001 Lianong, China). Optionally, the modacrylic may comprise Tairylon™ (available from Formosa Chemical & Fibre Corporation, 201 Tung Hwan Road, Teipei, Taiwan, R.O.C).
The FR viscose may be sourced from a plurality of different manufacturers to suit the FR, physical and mechanical performance as required. In particular, and optionally, the FR viscose comprises Lenzing FR™ (available from Lenzing Fibres Inc, Aktiengesellschaft, 4860 Lenzing, Austria). Optionally, the FR viscose may be sourced from Shandong Helon Co. Ltd, No 555, Hai Long Road, Hanging District, Wei Fang, SDG 261100, China (herein referred to as Helon FR).
Preferably, the natural cellulosic material comprises any one or a combination of the following set of: Natural Cotton; Bamboo; Linen; and/or Jute. Reference to ‘natural cellulosic’ refers to a cellulosic material that has not been pre-treated so as to change the chemical, physical or mechanical properties including in particular enhancement of FR. This term also refers to a material available from a biological source such as a plant or shrub. The term includes such natural materials that have undergone minimal processing such that the resultant materials cannot be categorised as synthetic or ‘man-made’.
Optionally, the blend may further comprise nylon in the amount trace to 7% by weight or more preferably trace to 5% by weight.
Optionally, the blend may further comprise a para-aramid material in the amount trace to 7% by weight or more preferably trace to 5% by weight.
Optionally, the blend may further comprise an antistatic material and in particular a carbon based antistatic material in the amount trace to 5% by weight. The carbon or non-carbon based antistatic material may be sourced from a plurality of different manufacturers to satisfy the desired physical and mechanical properties as required. However and preferably, the antistatic material comprises any one or a combination of the following set of: Beltron™ (available from KB Seiren Limited, 14-15F, Umeda Daibiru Building, 3-3-10, Umeda, Kita-ku, Osaka, 530-0001 Japan); Negastat™ (available from William Barnet & Son, LLC, 1300 Hayn Street, P.O. Box 131 Arcadia, S.C., 29320, United States of America); antistatic material and fibres available from Jarden, US; and/or Bekinox™ (available from Bekaert, President Kennedypark 18, B-8500 Kortrijk, Belgium).
Preferably, the fibre blend comprises 40% to 55% by weight of the modacrylic; 10% to 20% by weight of the natural cellulosic material; and 25% to 35% by weight of the FR viscose based material.
More preferably, the fibre blend comprises: 45% to 55% by weight of Protex™; 10% to 20% by weight of natural cotton; 25% to 35% by weight of FR viscose; trace to 7% by weight nylon; and trace to 5% by weight of a carbon based antistatic material.
More preferably, the fibre blend comprises: 45% to 55% by weight of Protex™ T; 10% to 20% by weight of natural cotton; 25% to 35% by weight of FR viscose; trace to 7% by weight para-aramid; and trace to 5% by weight of a carbon based antistatic material. According to a further aspect of a present invention there is provided a fabric comprising a fibre blend as disclosed herein. According to a further aspect of the present invention there is provided a garment comprising a fabric made from the fibre blend as disclosed herein.
The present blend of textile fibres is suitable to form yarns to construct fabrics and/or garments that are considered fire and flame retardant such that garments formed from the present yarns may be worn in conditions where there is any threat of heat or flame trauma. The present blend is further advantageous by including natural fibre components to facilitate a degree of comfort to the wearer which cannot be achieved with blends of wholly synthetic component. The present fabrics and garments comprise thermostable elements or components to ensure compliance with relevant health and safety requirements whilst being comfortable and lightweight but achieving a high degree of protection against heat and flame.
The present blend may be presented in blend form, as yarns formed from staple fibres, filamentous yarns, filaments including monofilaments and multifilaments. Fabrics according to the present invention are constructed via the use of the present blend or a union of the present blended fibres in woven, non-woven, or knitted form.
In one aspect, the present invention comprises a knitted fabric comprising a fibre blend as described herein further comprising an antistatic fibre or fibres as a fibre yarn or filament wherein the antistatic fibre is included in the range trace to 10% by weight. According to further aspect, the present invention may comprise a woven fabric formed from the present fibres in a blend or union optionally further including addition of an antistatic fibre or fibres included in the range trace to 10% by weight.
Advantageously, the present fabrics comprise thermostable yarns or filaments or a combination of yarns and filaments in which yarns or filaments of a first type are interlaid, interlinked, interwoven or looped with yarns or filaments of a second type to create a blended composite fabric structure.
The thermostable component may comprise anyone or a combination of the following set of:
The thermostable fibres may comprise any one or a combination of the following set of: melamines, polyimides, polyamideimides, partially oxidized polyacrylonitriles, novoloids, poly (p-phenylen benzothiazoles), polyphenylene sulphides, polyethyl- or polydiethyl-ketones, polyketones, polyetherimides, and combinations thereof.
Advantageously, the thermostable component of the fabric as identified herein, is used to form a ‘construct’ reinforcement component of the fabric that provides structural integrity to the fabric during and following exposure to heat and flame Preferably, the thermostable component is included as a minority component within the fabric with the majority component being formed from the yarns or filaments of the present fibre blend comprising a modacrylic, cellulosic and FR viscose. Reference within the specification to minority and majority component encompass volume and weight percentage relative amounts of the first yarn, the second yarn or filament type and the combined volume or weight percentage of the first and second yarn or filament types.
According to a further aspect of the present invention there is provided a flame retardant fibre blend comprising:
Optionally, the blend comprises 5 to 20% of a polyamide.
Optionally, the thermostable element is a blend and comprises any one or a combination of:
Optionally, the majority component fibre blend and/or the minority thermostable fibre blend includes an antistatic fibre (as described herein) included in the range trace to 10% by weight.
According to a further aspect of the present invention there is provided a flame retardant fabric having a composite structure comprising;
Preferably, the fabric comprises a woven structure wherein the majority of the warps and wefts of the weave comprise the first yarn type; and wherein the second yarn and/or filament type is interwoven as warps and wefts at spaced apart intervals amongst the warps and wefts formed from the first yarn type.
Preferably, the second yarn and/or filament type is interwoven with the first yarn type at a regular spacing in the range 5 to 15 ends and 5 to 15 picks. More preferably, the second yarn and/or filament type is interwoven with the first yarn type at a regular spacing in 10 ends and 10 picks.
The second yarn or filament type may comprise a single or two-ply structure. Where the second yarn and/or filament type comprises a two-ply structure, a first strand may comprise a yarn or filament formed from 100% by weight of the thermostable component and the second strand may comprise a yarn formed from the present blend. Optionally, the first strand may comprise 50:50 of the thermostable component and a modacrylic and the second strand may comprise 50:50 of the thermostable component and a modacrylic. Preferably, the first strand of the two-ply construct comprises 100% by weight para-aramid with the second strand comprising 100% by weight of the present blend.
Optionally, the second yarn or filament type may comprise a core spun construction wherein the central core strand comprises 100% para-aramid and the surrounding coil spun strand (sheath) comprises a yarn or filament formed from the present blend.
The second yarn or filament type is preferably interwoven with the first yarn type at regular spaced apart intervals. In particular, the second yarn or filament type may be included at a space in between every 5 to 15 warp and wefts formed from a yarn or filament of the first type. Accordingly, the second yarn or filament type is included within the fabric as a grid or mesh having warps and wefts included at every 10 ends and 10 picks of the fabrics in which the first yarn is the majority component. This second yarn or filament type therefore provides a ‘construct’ or reinforcement component to the fabric that maintains its physical integrity and warp and weft structure during and following exposure to flame and heat in excess of 500° C.
Reference within the specification to ‘a thermostable fibre that exhibits no appreciable decrease in mechanical strength’ encompasses a yarn or filament that retains the majority of its structure during and post exposure to heat in excess of 500° C. That is, where the thermostable yarn or filament is included as a component within a fabric in the form of a weft and warp, during and after exposure to heat in excess of 500° C., the thermostable warp and weft components of the fabric persist and have not perished to form a residual part of the fabric in the form of a grid or mesh that provides structural support for the majority component of the fabric that may have been charred, burnt, scorched, damaged and in some way degraded by the exposure to heat in excess of 500° C.
The present fibre blend is designed specifically for the manufacture of safety textiles being resistant to heat including extreme heat associated with molten metals, electric discharge and flames. The inventors provide a fibre blend and in particular a woven, non-woven, including a knitted fabric, that satisfies a number of different national performance test standards including in particular:
EN ISO 11611: 2007: Clause 6.1—tensile strength; Clause 6.2—tear strength; Clause 6.5—dimensional change; Clause 6.7—flame spread procedure A (surface ignition) and B (edge ignition); Clause 6.10—electrical resistance.
EN ISO 11612: 2008: Clause 7.4—molten aluminium splash; Clause 7.5—molten iron splash; Clause 7.6—contact heat.
NFPA 2112:2012: Section 7.1.1 Heat Transfer Performance (HTP; 7.1.2 flame resistance; 7.1.3 thermal shrinkage; 7.1.4 heat resistance; 7.1.5 predicted body-burn.
A protective fabric, particularly formed as a garment, capable of satisfying the above performance test requirements and based on a natural cellulosic material would provide significant advantages over existing FR fabrics. For example, the present safety fabric satisfies all of the above requirements and is capable of being characterised as a ‘universal’ safety fabric suitable for use in a variety of different hazardous environments as may be required by personnel working in for example, the military, rescue/emergency services and the metal manufacturing, utilities (oil, gas and electric), petrochemical and heavy industries.
The inventors identified the following criteria as being particularly important in the development of a universal heat resistant fibre
(a) required to pass the FR requirements of ISO11612 and associated Standards namely to withstand both face ignition source (as the previous Standard EN531) AND bottom-edge ignition source (as specifically required in the new replacement Standard ISO11612 and associated standards);
(b) required to have minimum tensile and tear strength properties of at least the minima specified in ISO11612 and EN11611
(c) required to achieve the requirements of Oekotex (Okotex) 100 “Standard”. Oekotex is a voluntary, non-Statutory, requirement for measurement of hazardous substances as defined only by the Oekotex organisation but may be used as a bench-mark by some end users. One of the qualifying criteria concerns the measurement of extractable antimony, which is used in the flame-retardant technology inherent to the modacrylic family of fibres.
Modacrylic fibres based on Protex™ W, Protex™ M, Protex™ Q and Protex™ T were identified as suitable components for the present fibre blend due to their FR grading. However, Protex™ T is generally acknowledged to be less ‘protective’ when employed in the manufacture of a garment due to its expected performance with respect to ‘charring’protection (associated with barrier formation within the textile to prevent flame penetration).
The present fibre blend is advantageously suited to form a blended spun yarn
As will be appreciated, the present blend may be used to form a yarn via a process of mixing, carding, drawing, roving, spinning, twisting and winding as will be appreciated by those skilled in the art. In particular, the present fibre blend is specifically non-slickened or siliconised such that the staple fibres may be spun and/or twisted together to form the composite yarn structure wherein the fibres are held together via frictional contact being facilitated by the spinning and twisting construction as described above.
To illustrate the present invention, the following examples are provided. Test results, for the above criteria are also presented and confirm the advantages of the subject invention and its suitability for use as a component fibre of a protective textile and garment exhibiting degradation resistance to a variety of different hazardous environmental conditions involving significant elevated temperatures.
A fibre blend was ring spun on a cotton system to 40/2 NM. The fabric was woven to a twill construction at approximately 360 gsm. The fibre blend comprised 50% Protex™ M; 30% Helon FR viscose; 15% cotton and 5% nylon.
A fibre blend was ring spun on a cotton system to 40/2 NM. The fabric was woven to a twill construction at approximately 360 gsm. The fibre blend comprised 50% Protex™ W; 30% Helon FR viscose; 15% cotton and 5% nylon.
A fibre blend was ring spun on a cotton system to 40/2 NM. The fabric was woven to a twill construction at approximately 360 gsm. The fibre blend comprised 50% Protex™ T; 30% Helon FR viscose; 15% cotton and 5% nylon.
A fibre blend was ring spun on a cotton system to 40/2 NM. The fabric was woven to a twill construction at approximately 360 gsm. The fibre blend comprised 50% Protex™ M; 30% Lenzing™ FR viscose; 15% cotton and 5% nylon.
A fibre blend was ring spun on a cotton system to 40/2 NM. The fabric was woven to a twill construction at approximately 360 gsm. The fibre blend comprised 50% Protex™ W; 30% Lenzing™ FR viscose; 15% cotton and 5% nylon.
A fibre blend was ring spun on a cotton system to 40/2 NM. The fabric was woven to a twill construction at approximately 360 gsm. The fibre blend comprised 50% Protex™ T; 30% Lenzing™ FR viscose; 15% cotton and 5% nylon.
Performance testing was undertaken for the fibre blends of examples 3 and 6 and the results are presented in tables 1 to 6 below.
Tables 1 to 3 detail the experimental performance test results for the blend formulation of example 3 according to the identified performance criteria of each of the two standards EN ISO 11611: 2007; EN ISO 11612: 2008
Standard: Clause 6.1—tensile strength; Clause 6.2—tear strength; Clause 6.5—dimensional change; Clause 6.7—flame spread procedure A (surface ignition) and B (edge ignition); Clause 6.10—electrical resistance.
Pre-treatment: for 6.1, 6.2, 6.5 and 6.10 tests were made after 5 washing cycles in accordance with ISO 6330: 2000. Procedure 6A at 40° C. drying procedure E: tumble dry. The tumble drying was carried out after the completion of each wash. For 6.7 tests were made in the as received condition.
Standard: Clause 7.4—molten aluminium splash (D); Clause 7.5—molten iron splash (E); Clause 7.6—contact heat (F).
Pre-treatment: tests were made after 5 washing cycles in accordance with ISO 6330: 2000. Procedure 6A at 40° C. drying procedure E: tumble try. The tumble drying was carried out after the completion of each wash.
Specimen 3
5.1
Tables 4 to 6 detail the experimental performance test results for the blend formulation of example 6 according to the identified performance criteria of each of the two standards EN ISO 11611: 2007; EN ISO 11612: 2008
Standard: Clause 6.1—tensile strength; Clause 6.2—tear strength; Clause 6.5—dimensional change; Clause 6.7—flame spread procedure A (surface ignition) and B (edge ignition); Clause 6.10—electrical resistance.
Pre-treatment: for 6.1, 6.2, 6.5 and 6.10 tests were made after 5 washing cycles in accordance with ISO 6330: 2000. Procedure 6A at 40° C. drying procedure E: tumble dry. The tumble drying was carried out after the completion of each wash. For 6.7 tests were made in the as received condition.
Standard: Clause 7.4—molten aluminium splash (D); Clause 7.5—molten iron splash (E); Clause 7.6—contact heat (F).
Pre-treatment: tests were made after 5 washing cycles in accordance with ISO 6330: 2000. Procedure 6A at 40° C. drying procedure E: tumble try. The tumble drying was carried out after the completion of each wash.
Specimen 3
4.9
A fibre blend was ring spun on the cotton system to 60/2 Nm. The fabric was woven to a twill structure at approximately 190 gsm (or 5.5 oz per sq yd). The fibre blend comprised of 50% Protex™ C; 30% Helon FR viscose, 15% cotton and 15% para-aramid, with addition to 2% of antistatic fibres, all in intimate blend. Additional a reinforcement structure in the form of a grid at intervals of 10 ends and 10 picks was interwoven into the structure of the main fabric.
Independent testing body: Vartest Laboratories, New York, USA Accredited to ISO/IEC 17025: 2005
Minimum of Three items to be tested. Tested as received.
Immediately after specified exposure, the specimens shall be removed and examined for evidence of ignition, melting and dripping or separation.
Specimens shall be measured for shrinkage. Not to exceed 10% in either direction.
Dimensional change: Avg. Length Direction=−3.0%, Avg. Width Direction=−3.9%
Result: PASS when evaluated after heat at 500° F.
Test temperature: 500° F., Test Exposure Time: 5 Minutes
Minimum of Three items to be tested. 3× per NFPA 2112 Section 8.1.3
Immediately after specified exposure, the specimens shall be removed and examined for evidence of ignition, melting and dripping or separation.
Specimens shall be measured for shrinkage. Not to exceed 10% in either direction.
Dimensional change: Avg. Length Direction=−5.4%, Avg. Width Direction=−5.8%
Result: PASS when evaluated after heat at 500° F.
NFPA 2112 Sections 7.1.5; 8.5 Predicted body Burn by Instrumented Manikin
Test according to the ISO13506 “Protective clothing against heat and flame, test method for complete garments, Prediction of burn injury using an instrumented manikin” European Test equivalent to ASTM F 1930
Independent testing body: Empa, Swiss Federal Laboratories for Materials Science and Technology St. Gallen, Switzerland
International Standard ISO 13506: 2008
“Protective clothing against heat and flame—Test method for complete garments—Prediction of burn injury using an instrumented manikin”
The test specimen was placed onto an adult sized manikin and exposed to a laboratory flash fire simulation with controlled heat flux, duration and flame distribution. Heat which was transferred through the test specimen during and after exposure was measured with the heat flux sensors. A software programme calculates the various degrees of burns and the total burn area.
The complete procedure (manikin, burners and test room) is regulated with a special computer programme which also records the sensors' activities and calculates the various areas of burn and degrees of burn.
The measurements are taken on the fully dressed manikin. Length of fabric at specific points on the garment is measured with a metal ruler. Shrinkage is assessed as percentage of the measure after flame exposure to the one measured before.
Table of burn prediction and graphical display of distribution of burns on the manikin. Total area of predicted pain, 1st, 2nd and 3rd degree burn injury (based on the area of manikin containing valid heat flux sensors) 60 s after beginning of flame exposure. Detailed information about the results of each sensor can be found in the attached tables.
The width of gap between the conductive threads was measured in five areas with a steel rule.
The sample was conditioned and tested at 23+/−1° C. and 25+/−5% r.h.
The charge decay time and shielding effect were measured according to BS EN 1149-3: 2004 Method 2 (induction charging)
Based on the tests carried out on the sample supplied:
a) for a material containing conductive threads in a stripe or grid pattern the spacing of the conductive threads in one direction shall not exceed 10 mm.
b) the results of BS EN 1149-3 Method 2: 2004 meet the requirements specified in BS EN 1149-5: 2008 of the shielding factor being greater than 0.2 and/or the half decay time being less than 4 seconds.
In accordance with Annex G of EN ISO 11612: 2008 the uncertainty of measurement associated with the test methods was not taken into account.
Independent testing body: Shirley Technologies Ltd, Manchester, UK
Article Description: Blue dyed woven fabric Ref: Protal 5 NG/WAX-129
Blue dyes woven fabric sample was submitted for testing the extractable antimony content.
The samples submitted were as follows:
Sample 1: Blue dyed woven fabric
The sample was extracted in artificial sweat solution and analysed on the inductively coupled plasma (ICP)
Detection limit of this test is—0.8 mg/kg
The performance test results, for examples 3 and 6 confirm the fabrics satisfy all of the desired requirements. In particular, the blend of example 3 was found to perform better than the blend of example 6 with regard to tensile strength, tear strength, electrical and contact heat resistivity. The Oekotex standard requirements were also satisfied for both samples 3 and 6 following respective testing.
The performance test results for Example 7 show compliance with both the sections of US Standard NFPA 2112 which relate to a fabric (namely Sections 7.1.1, 7.1.2, 7.1.3, 7.1.4 and 7.1.5) as well as the EU standards EN11612, and EN14116 for FR performance of garments, with EN1149-5 for anti-static performance and thus shows a “Universal Compliance”: the test results for Oekotex100 limit for extractable antimony illustrates that the fabric would conform to the whole Oekotex 100 requirement as there is known compliance for all other elements.
The presented results confirm that the present fibre blend based on the combination of a modacrylic with a natural cellulosic material and a FR viscose, at the appropriate weight % is capable of satisfying different performance standards with regard to fabric safety. This is perhaps contrary to expectation as, for example, cotton fibres are not considered to be inherently flame resistant and are susceptible to burn. The inventors have realised a synergistic affect between the blend of a modacrylic with a natural cellulosic (natural cotton) and FR viscose. The effect is manifested in an observed increase in the combined limited oxygen index (LOI) of the fabric wherein the LOI of the blend is greater than the sum of the LOI of the individual components. As will be appreciated, the LOT refers to the minimum concentration of oxygen that will just support flaming combustion of a material. The affect of incorporating a natural cellulosic may be considered to increase the charring affect of fabric when exposed to extreme heat which increases the LOI by expelling oxygen within the matrix as the charred carbon barrier forms during initial heat contact.
The present invention is therefore advantageous for use as a ‘universal’ protective fabric that has exhibited proven performance as a protective layer to flame, electric discharge and molten metal hazards.
A fibre blend comprising 50% Protex™; 30% Helon FR viscose; 15% cotton 5% para-aramid was mixed, carded, drawn, roved, spun and wound to create a yarn according to a first yarn type. A second yarn type having a two-ply construction was formed by the same spun yarn process of as the first yarn using a fibre blend comprising a 50% by weight para-aramid (for example KEVLAR by E.I. Du Pont de Nemours and Co) and 50% by weight of the fibre blend of the first fibre type.
A woven fabric was constructed using the first yarn type as a majority component via interweave of warps and wefts. The second yarn type was interwoven with the first yarn type (as a single weave assembly) at every 10 ends and 10 picks (with respect to warps and wefts). Accordingly, the resulting fabric structure comprised predominantly warps and wefts of the first yarn type and interwoven warps and wefts of the second yarn type spaced at regular intervals to create a grid network repeated every 10 ends and 10 picks.
| Number | Date | Country | Kind |
|---|---|---|---|
| GB0813401.7 | Jul 2008 | GB | national |
| PCT/GB2009/050676 | Jun 2009 | GB | national |
This application is a continuation-in-part of U.S. patent application Ser. No. 13/055,239, filed on Apr. 4, 2011, which claims priority to and all the benefits of International Patent Application Ser. No. PCT/GB2009/050676, filed on Jun. 15, 2009, which claims priority to and all the benefits of Great Britain Patent Application Ser. No. GB0813401.7, filed on Jul. 22, 2008, each of the specifications of which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13055239 | Apr 2011 | US |
| Child | 13842988 | US |
