Protective fabric and process of manufacturing same

Abstract

A fabric for use in arc and flame protection, and a process for producing a fire resistant fabric are provided. The fabric includes at least 70 wt % aramid fiber; less than 40 wt % modacrylic; 8 wt % nylon; and 2 wt % anti-static. The process includes shredding recycled fire resistant garments into fibers; creating yarn from the shredded fibers; weaving the yarn into fabric; and knitting the yarn to produce new garments. The fabric may be used to produce fire-resistant garments worn by workers in many industries such as the oil and gas.

Claims

1. A process for producing a fire resistant fabric, comprising: shredding recycled fire resistant garments into fibers such that the fibers comprise: approximately 70 weight percent (wt %) aramid fiber; approximately 20 wt % modacrylic; approximately 8 wt % nylon; and approximately 2 wt % anti-static; creating yarn from the shredded fibers; and weaving the yarn into the fire resistant fabric.

2. The process according to claim 1, further comprising dry cleaning the recycled garments using a chemical solvent, prior to the shredding.

3. The process according to claim 2, wherein chemical solvent is tetrachloroethylene.

4. The process according to claim 1, further comprising removing non-fire resistant components from the recycled garments, prior to the shredding.

5. The process according to claim 2, wherein the shredding is done by an industrial fabric shredder.

6. The process according to claim 1, wherein said weaving the yarn comprises carding the shredded fabric to produce a sliver.

7. The process according to claim 6, wherein carding is done by hundreds of wires in a carding machine.

8. The process according to claim 6, wherein said weaving the yarn further comprises feeding the sliver through a roving machine.

9. The process according to claim 8, wherein the sliver is twisted and elongated by the roving machine.

10. The process according to claim 1, wherein the weaving is done using a loom.

11. The process according to claim 1 further comprising: knitting the fire resistant fabric to produce new garments.

12. The process of claim 11, further comprising dying the fire resistant fabric.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the figures which illustrate by way of example only, embodiments of the present invention,

(2) FIG. 1 depicts a process for producing fabric from recycled components;

(3) FIG. 2 shows test results for a 3-second exposure to flame test on blue standard coveralls made from 70% aramid, 20% modacrylic, 8% nylon, and 2% anti-static, tested with 100% cotton t-shirt and briefs;

(4) FIG. 3 shows test results for a 5-second exposure to flame test on blue coveralls with visibility trim, double layer elbows and knees, made from 70% aramid, 20% modacrylic, 8% nylon, and 2% anti-static, tested with 100% cotton t-shirt and briefs;

(5) FIG. 4A shows detailed parameters and results of the 3-second test having burn number 4309 from FIG. 2;

(6) FIG. 4B is a graph depicting the percentage burn versus time for burn number 4309;

(7) FIG. 5A shows detailed parameters and results of the 3-second test having burn number 4312 from FIG. 2;

(8) FIG. 5B is a graph depicting the percentage burn versus time for burn number 4312;

(9) FIG. 6A shows detailed parameters and results of the 3-second test having burn number 4314 from FIG. 2;

(10) FIG. 6B is a graph depicting the percentage burn versus time for burn number 4314;

(11) FIG. 7A shows detailed parameters and results of the 5-second test having burn number 4311 from FIG. 3;

(12) FIG. 7B is a graph depicting the percentage burn versus time for burn number 4311;

(13) FIG. 8A shows detailed parameters and results of the 5-second test having burn number 4313 from FIG. 3;

(14) FIG. 8B is a graph depicting the percentage burn versus time for burn number 4313;

(15) FIG. 9A shows detailed parameters and results of the 5-second test having burn number 4315 from FIG. 3; and

(16) FIG. 9B is a graph depicting the percentage burn versus time for burn number 4315.

DETAILED DESCRIPTION OF THE EMBODIMENT

(17) A process 100 for producing a fire resistant fabric is shown at a high level in FIG. 1. The process begins with the collection and shredding 110 of used garments such as coveralls. The garments may initially have contaminants such as oil, dirt, etc. present thereon. These contaminants may be removed through dry cleaning using a chemical solvent such as tetrachloroethylene (perchloroethylene) commonly known as “PERC”. The garments may then be processed by manually removing any non-fire resistant components such as zippers, snaps, hook and loop fasteners (e.g. Velcro®), etc. After removal of these non-fire resistant components, the garments are shredded by means of an industrial fabric shredder to produce recycled fibers.

(18) At step 120, the recycled fibers are used to make yarn through carding by hundreds of fine wires in a carding machine, as is known in the art. The carding machine separates the fibers and produces a rope like strand of parallel fibers called a sliver. The sliver is fed through at least one roving machine, as is known in the art, where it is elongated and given additional twists to produce yarn.

(19) At step 130, the yarn is woven into a fabric using a loom as is known in the art.

(20) The fabric is then knitted at step 140, and then dyed and converted back into garments at step 150.

(21) In the most preferred embodiment, the resulting fabric is 6 to 7 oz twill comprising: 70 wt % aramids; 20 wt % modacrylic; 8 wt % nylon; and 2 wt % anti-static material. The warp comprises approximately ⅔ of the total weight of the fabric whereas the weft comprises approximately ⅓ of the total weight of the fabric.

(22) The warp is 45 wt % aramids, 13 wt % modacrylic, 6.5 wt % nylon, and 0.65 wt % anti-static material based on total fabric weight. For the warp aramids, 49 wt % are virgin aramid and 20% wt are recycled aramids based on the total fabric weight. Based on only the weight of the warp, the warp comprises 69 wt % meta-aramids, 19 wt % modacrylic, 10 wt % nylon, and 2 wt % anti-static.

(23) The weft is 26 wt % aramids, 7 wt % modacrylic, 2 wt % nylon, and 1.4 wt % anti-static material based on total fabric weight. For the weft aramids, 55 wt % are recycled aramids and 18 wt % are virgin aramids based on total fabric weight. Based only on the weight of the weft, the weft comprises 73 wt % meta-aramids, 20 wt % modacrylic, 5 wt % nylon, and 2 wt % anti-static.

(24) The Applicant has found that the resulting fabric produces unexpected and superior performance in mannequin burn tests. The garments were tested in accordance with ASTM F1930-15 Standard Test Method for Evaluation of Flame Resistant Clothing for Protection Against Fire Simulations Using an Instrumented Manikin. The test results were conducted by the Protective Clothing and Equipment Research Facility (PCERF) at the University of Alberta (reference number P23-009-13). Appendix A, herein incorporated by reference in its entirety. Two garment systems were evaluated by the tests:

(25) 1. Blue standard coveralls, GR 2015-TW-1, 70% aramid/20% modacrylic/8% nylon/2% anti-static, tested with 100% cotton t-shirt and briefs; and

(26) 2. Blue coveralls with visibility trim, double layer elbows and knees, GR 2015-TW-1, 70% aramid/20% modacrylic/8% nylon/2% anti-static, tested with 100% cotton t-shirt and briefs.

(27) The test apparatus used comprised a thermally instrumented mannequin. Flash fires were produced with propane diffusion flames. One hundred and ten stimulant sensors were used to measure the rate of heat transfer to the mannequin. A computer controlled data acquisition system was used to run the test, record and store the data, calculate the extent and nature of the skin damage, and display the results. The sampling rate of the system was 1100 Hz.

(28) The tests were conducted on Sep. 24, 2015. The exposure heat flux at the start of the test was 82.4 kW/m.sup.2, and at the end was 80.7 kW/m.sup.2. The test room temperature ranged from 15° C. to 22° C., and the relative humidity ranged between 40% and 50%. Sensor temperature measurements (data collection) were taken for 60 seconds during and after flame exposure. The specimen garments were laundered one time as per AATCC (Association of Textile, Apparel and Materials Professionals) method 135 91, V A iii), as described in ASTM F1930-15 paragraph 9.1.4, and conditioned at 21° C. and 65% relative humidity for a minimum of 24 hours after laundering. Garments were tested within 10 minutes of removal from the conditioned environment.

(29) Tests performed on the first garment system (GR 2015-TW-1 Standard Coveralls) for a 3-second exposure resulted in 14.5% of the mannequin surface receiving 2.sup.nd and 3.sup.rd degree burns, and 7.3% of the mannequin surface under the garment receiving 2.sup.nd degree burns. These results were calculated as the mean of the burn predictions over three replications of the test. The three replications of the 3-second test are summarized in FIG. 2. More details of the test replications are provided in FIGS. 4A, 4B, 5A, 5B, 6A, and 6B. With reference to FIG. 2, it is clear that the garment protected the mannequin surface such that there were no (0%) 3.sup.rd degree burns, and only approximately 7.3% of the surface received 2.sup.nd degree burns. FIGS. 4A, 5A, and 6A show summarized test parameters and results for the three replications of the 3-second test. FIGS. 4B, 5B, and 6B are graphs depicting the percentage of total mannequin surface reaching criteria for 3.sup.rd degree burn (in square dots) as well as the percentage of total mannequin surface reaching criteria for 2.sup.nd and 3.sup.rd degree burn (in circular dots), versus time.

(30) Tests performed on the second garment system (GR 2015-TW-1 Coveralls with visibility trim) for a 5-second exposure resulted in 25.6% of the mannequin surface receiving 2.sup.nd and 3.sup.rd degree burns, and 21.8% of the mannequin surface under the garment receiving 2.sup.nd degree burns. These results were calculated as the mean of the burn predictions over three replications of the test. The three replications of the 3-second test are summarized in FIG. 3. More details of the test replications are provided in FIGS. 7A, 7B, 8A, 8B, 9A, and 9B. With reference to FIG. 3, it is clear that the garment protected the mannequin surface such that there were no (0%) 3.sup.rd degree burns, and only approximately 21.8% of the surface received 2.sup.nd degree burns. FIGS. 7A, 8A, and 9A show summarized test parameters and results for the three replications of the 5-second test. FIGS. 7B, 8B, and 9B are graphs depicting the percentage of total mannequin surface reaching criteria for 3.sup.rd degree burn (in square dots) as well as the percentage of total mannequin surface reaching criteria for 2.sup.nd and 3.sup.rd degree burn (in circular dots), versus time.

(31) Although the embodiments described herein demonstrate fabric of between 6 to 7 oz twill, other embodiments may be a fabric of between 5.25 to 8 oz twill.

(32) Although the embodiments described herein demonstrate a particular process for making yarn and fabric, other processes may be used as is known in the art to produce fabric with similar characteristics as described herein.

(33) The above-described embodiments are intended to be examples of the present invention and alterations and modifications may be effected thereto, by those of skill in the art, without departing from the scope of the invention, which is defined solely by the claims appended hereto.