JP3107600B2 - Electric arc resistant lightweight fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This is a continuation-in-part of the applicant's serial number 07 / 528,358, filed on May 25, 1990.

[0002] Garments made from flame-resistant fibers provide electrical workers with protection from the intense radiation emitted by the strong electric arc that can pass nearby in the event of an accidental discharge in high voltage equipment. Although provided, this type of garment is made from flame-resistant cotton fabric (FR cotton fabric) and is unpleasant in a warm environment because of the heavy weight fabric required for reasonable protection. These garments can be made lightweight and still provide reasonable protection if made from certain flame resistant synthetic fibers, but due to the reduced moisture absorption compared to FR cotton fabrics, Is also uncomfortable.
Obviously lightweight fabrics with improved electrical arc shielding are needed by electrical workers to provide comfort and protection.

[0003]

SUMMARY OF THE INVENTION The present invention provides 15-50% of at least 25
A staple fiber having a limiting oxygen index (LOI) of 50 to 85% and a flame resistant cotton yarn of 50 to 85%;
Each of the above yarns contains 50% heat resistant staple fibers and 50-100% flame resistant cotton yarns.
− 135 to 20 with a linear density of 550 decitex
3 has a basis weight of g / m ^2, while still giving a high degree of comfort to the wearer with a high degree of resistance to radiant energy from high voltage electric arc, a woven fabric suitable for use in clothing provide.

[0004]

DETAILED DESCRIPTION OF THE INVENTION As used herein, staple fibers are textile fibers suitable for clothing, that is, having a linear density of less than 10 dtex per fiber, preferably less than 5 dtex per fiber. . Even more preferred are fibers having a linear density of about 1 to about 3 dtex per fiber and a length of about 1.9 to 6.3 cm (0.75 to 2.5 inches). From the viewpoint of aesthetics and processability of the woven fabric, crimped yarn is preferred.

"Heat resistance" is defined as the heat resistance time measured as described herein at least 0.018 seconds / g / m2.
² means (0.6 sec / oz / yd ²⁾ to increase the fiber. For comparison, flame resistant cotton yarn has a LO of 30.
It has a heat resistance time of only 0.01 s / g / m ² , and is considered flame resistant (LOI> 25) but not heat resistant.

[0006] The method for producing the fabric according to the present invention comprises 15
There are several stages of first producing a mixture consisting of 50% heat-resistant staple fibers and 50-85% cotton yarn. From this mixture, yarns from the 195 to 500 decitex (nominal 12th [cc] to 30th) monofilament yarn are spun, and these yarns as warp yarns, 0-50% heat-resistant fiber and 50-100% A basis weight of 118-187 g / m ² (3.5
– Weave 5.5 oz / yard ² ) fabric. A yarn having a lower linear density can be twisted to a similar linear density.

The fiber is then converted to a commercially available flame retardant, for example, Abright & Wils.
on Inc., PO. Box 26229, Richmond, VA) “Proban CC” or Ciba Geigy (Ciba-G)
Treat with "Pyrovatex CP" from Eygy. Both treatments are based on Japan Textile News ( Japane
se Textile News ), No. 394, 394, September 1987. Base weight after flame treatment is 135 to 203
g / m ² (4-6.0 oz / yard ² ) and a linear density of 215 to 550 decitex.

The amount of heat-resistant fiber required in the weft direction of the woven fabric according to the present invention varies depending on the structure of the woven fabric. For plain weave fabrics, wefts require at least 15% heat resistant fibers and up to 85% cotton yarn, while 2 x 1 and 3
In the × 1 twill woven fabric, all the weft yarns may be FR cotton yarns. Too little heat resistant fiber in the warp can result in tearing of the fabric when exposed to an electric arc created by the discharge of a high voltage device. On the other hand, an excess of heat-resistant fibers results in a loss of the desired aesthetic appearance of the cotton yarn and increases costs.

It has been found that in 2 × 1 or 3 × 1 twill weaves, the heat-resistant fibers need only be present in the warp yarns, ie, all the weft yarns may be cotton yarns. If the warp faces the arc, i.e. on a surface remote from the wearer of the garment, severe tearing is avoided. Under the reverse conditions, where the surface of the warp is away from the arc and the 100% FR cotton-filled yarn is exposed, severe tearing of the fabric can occur even if a sufficient amount of heat-resistant fiber is present in the warp. Would. With a sufficient amount of heat resistant fibers in both the warp and weft yarns, the fabric will resist tearing in any direction. The survivability of the 2 × 1 and 3 × 1 twills with 100% FR cotton weft is believed to be due to the long warp that shields the weft on the surface exposed to the arc and preferentially absorbs radiation. ing. Minimum although in that it meets the criteria for the fabric cleavage 2 × 1 twill is better than plain weave, the 3 × 1 Z twist twill 1
This is even more preferred since it does not split even if it has a 00% cotton weft yarn. This is a 3 x 1 twill float 2
× 1 twill longer than that of, and is believed to be due to be given elasticity by "z" twist yarns of Z twist configuration.

[0010] Textile of the present invention described containing a mixture of FR cotton and heat resistant fibers, from good electrical arc than fabrics made with all flame resistant synthetic fibers having a basis weight equivalent to the currently marketed Protection against blast and heat.

[0011] Table 1 shows that under severe and mild exposure conditions, the fabrics of the present invention exhibit heavier poly (m-phenyleneisophthalamide) (MPD-I) / poly (p-phenylene). Terephthalamide) (PPD-T) 9
It is as good as a 5/5% fiber blend fabric, indicating better performance than the flame resistant cotton fabric used in garments normally worn by electricians.

The use of yarns in the fabrics of the present invention exceeds 500 decitex, as the use of such heavy yarns in lightweight fabrics results in an undesired unprotected fabric and results in poor protection to the wearer. It is important not to. If the yarn size is less than 215 decitex, the thickness of the lightweight fabric will be insufficient to protect against damage from absorbed radiation and the fabric will tear.

[0013] The fibers can be spun into yarns by several different spinning methods, including, but not limited to, ring spinning, air jet spinning and friction spinning. Both mixtures and sheath-core types are possible.

An exemplary heat resistant fiber for use in the present invention is poly (p-phenylene terephthalamide) (PP
DT) (LOI 28, heat resistance time 0.04 sec / g / m) staple fiber. This fiber can be made as described in U.S. Pat. No. 3,767,756 and is commercially available.

Other heat resistant organic staple fibers that may be used include, but are not limited to: terephthalic acid, as described in US Pat. No. 4,075,172, and 3,4 Fiber of a copolymer of a mixture of '-diaminophenyl ether and a diamine consisting of p-phenylenediamine (LOI 25, heat resistance time 0.024 sec /
g / m). Polybenzimidazole is also suitable (LOI
41, heat-resistant time 0.04 seconds / g / m).

[0016]

[Test measurement]

[0017]

Test for determining the resistance to [arc resistance test] arc, exposing the fabric in air, one feet away to two electric arc which is generated by applying 15,000 volts to the electrodes placed Things. A small copper wire connected to the electrode is used to initiate the arc. At the beginning of the arc, reduce the voltage to an average value of 500 volts RMS (root mean square) and apply 8,000 amps RMS current for 1/6 second using 60 cycles of alternating current.

Two levels of exposure were used. For more severe tests, the sample (30 cm) at a distance of 15 cm from the arc
× 30 cm) in a frame. 20 x 20 c in center
Because a 30 x 30 cm, 0.8 cm thick stainless steel plate with m openings was placed in the arc-facing frame, only 20 x 20 cm of the sample was exposed to the arc.
The specimen is clamped between a stainless steel plate, a 0.63 cm fenric spacer (constructed similarly to the stainless steel plate) and a 0.08 cm copper plate. This creates a gap of 0.63 cm between the specimen and the copper plate.
For tests under mild exposure, a mannequin wearing a 100% cotton yarn tee shirt is wrapped with a shirt made from the textile and placed at a distance of 20 cm from the arc.

[0019] To pass the arc resistance test, the fabric or shirt must not form a tear greater than 7.5 cm in length or 0.75 cm in width. If more than two tears occur, or if the tee or outer shirt ignites, the sample has failed the test.

[0020]

[Heat-resistant time] The heat-resistant time is measured using a device for measuring the tearing of the fabric described in U.S. Pat. No. 4,198,494. Use the same heating conditions as the above patent, but modify the sample holder (2.5 x 2.5 cm strip) to
Expose an area of × 6.3 cm to the heat flow. One end of the sample is fixed and the other end is connected to a 1.8 kg weight suspended by a thread through a pulley and placed under a 1.8 kg tensile load. The load is applied only in the warp direction, and the measurement is performed on the fabric with the surface of the fabric facing downward and facing the flame. The time recorded is the time required to break the sample. The time to tear of the sample in seconds divided by the basis weight of the fabric in g / m is reported as the heat residence time. This type of heating device is available from Custom Scientific Instruments, Inc.
entificInstruments Inc., 13 Wing Drive, Cedar Knol
ls, NJ 07927) as CS-206.

With respect to the measurement of the heat resistance time, a woven fabric from staple fibers or a continuous filament yarn can be used. A plain woven fabric having substantially the same number of warp and weft yarns of the same type should be used. The basis weight of the fabric should be 170 to 340 g / m (5-10 ounces / yard).

[0022]

[Limited oxygen index] This was measured using ASTM method d2863-77.

[0023]

Example 1 An arc resistant fabric according to the present invention was prepared from a ring spun yarn of an intimate mixture of PPD-T staple fibers and cotton yarn.

A picker-blend silver of 30% PPD-T fiber having a linear density of 1.65 dtex (1.5 dpf) with a cut length of 3.8 cm (1.5 inches) and 70% carding was applied to a ring spinning frame using a conventional cotton yarn system. 1cm using
Each yarn was processed into a spun yarn having seven "z" twists (18.5 tpi). The yarn produced in this manner is a single yarn spun yarn of 272 dtex (nominal 21.5 count; 247 denier), which is used as a warp in a shuttle loom and is 100% having the same twist and linear density as the warp. A 3 × 1 left- twisted twill weave configuration was made with a single spun filled yarn made from cotton yarn. This twill fabric has 30 warp yarns per cm x 1
19 wefts per cm (76 warps per inch x 47 wefts per inch) and 162 g / m
(4.8 ounces / yard). The fabric is dyed blue and then from Abright F. Wilson's "Proba
n) Flame retardant available as CC ", molar ratio 2: 1
With an aqueous solution of tetrakis- (hydroxymethyl) phosphonium chloride (THPC) / urea concentrate. The fabric was turned into a shirt and the warp was hooked on a mannequin 20 cm from the electric arc. The shirt did not cleave or ignite, and the tee shirt did not ignite when subjected to the mild exposure arc resistance test. If the shirt is turned over and the cotton-filled yarn is directed at the arc and subjected to the same test, the shirt will tear vertically over the entire length of one side and
A 5 cm breach occurred.

[0025]

Example 2 A 3 × 1 right- twisted twill woven fabric was constructed using the warps described in Example 1 in both the warp direction and the weft direction. 20 cm from arc after treatment with flame retardant
The fabric also passed the arc resistance test (mild exposure) when tested as a shirt on a mannequin.

[0026]

Example 3 A warp yarn as described in Example 1 having a linear density of 354 dtex (nominal 16.5 count, 322 denier)
Using a 100% cotton weft to constitute a 2 × 1 of the right twist twill fabric. This fabric has 30 warp yarns per cm ×
14 wefts / cm (76 warps / inch x 36 wefts / inch) and 162g /
m (4.8 ounces / yard).
Shirt of this fabric (after flame resistance treatment) 20 cm from arc
The mannequin was exposed with the warp facing outwards and subjected to an arc resistance test, which revealed only two small tears and no post-flame or ignition of the tee shirt. When turned over, the shirt was torn open due to excessive breakage.

[0027]

Example 4 A 3 × 1 right- twisted twill woven fabric was produced in the same manner as in the fabric of Example 2. 50% PPD-T and 50
% Cotton yarn was used for both the warp and weft yarns. The fabric was tested as a shirt (warp outward) on a mannequin 20 cm from the arc and passed the arc resistance test.

[0028]

Example 5 A fabric similar to that of Example 1 was produced except that the weft yarn had a linear density of 354 dtex (nominal 16.5 count, 322 denier). This fabric is 1cm
30 warp yarns per 1 x 16 weft yarns per 1cm (1
It had a configuration of 76 warps per inch x 41 wefts per inch) and a basis weight of 179 g / m (5.3 oz / yard). The fabric passed the arc resistance test when tested as a shirt on a mannequin 20 cm from the arc.

[0029]

Example 6 Both warp and weft are 15% PPD-T
/ 85% cotton yarn and constituted a plain woven fabric having a linear density of 390 dtex (15th, 354 denier) between warp and weft. This fabric was dyed green,
21 warp yarns per cm x 20 weft yarns per cm (54 warp yarns per inch x 50 warps per inch
Composition and 203 g / m (6.0 oz / yard)
And the basis weight. The fabric passed the more severe arc resistance test when held in a frame 15 cm from the arc.

[0030]

TABLE 1 TABLE Comparison moderate exposure arc testing of an embodiment of the present invention described and Control Example - mannequin basis weight of the arc from the 20 cm (g / m) Test results MPD-I / PPD-T ( 95 / 5%) 203 Passed 100% FR Cotton Yarn 203 Dropped Example 1-4 162 Passed Example 5 179 Passed Severe Exposure-Frame 100% FR 15cm from Arc 100% FR Cotton Yarn 203 Dropped Plain Weave 291 Dropped PPD-T / FR Cotton Yarn 50 / 50% warp 100% FR cotton filled yarn Example 6 203 Passed The main features and aspects of the present invention are as follows.

1. 15-50% of a heat-resistant staple fiber having a limiting oxygen index of at least 25 and 50-85%
Having a flame-resistant cotton, 215 -550 has warp threads having a linear density of dtex, having a basis weight of 135 to 203 g / m ^2, Note radiant energy from the electric arc while providing a high degree of comfort to the wearer Woven fabric suitable for use in clothing that is resistant to.

2. The woven fabric according to claim 1, wherein the heat-resistant fiber is poly (p-phenylene terephthalamide).

3. The woven fabric according to claim 1, wherein the woven fabric is a 3 × 1 twill weave.

4. The woven fabric according to claim 3, wherein the yarn composition is a 3 × 1 left hand twill weave, and the weft yarn is 100% flame-resistant cotton yarn.

5. 2. The woven fabric according to claim 1, wherein the woven fabric is a 2 × 1 twill weave.

6. 2. The woven fabric according to claim 1, wherein the woven fabric is plain woven, and the weft yarn contains at least 15% of heat-resistant fiber and up to 85% of flame-resistant cotton yarn.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-196741 (JP, A) JP-A-51-72677 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D03D 1/00-27/18

Claims (3)

(57) [Claims] 1. A 15 - 50% of the heat-resistant staple fibers and 50 having at least 25 restriction oxygen index - Ri Na contain mixed yarn of 85% of the flame resistant cotton, has a linear density of 215 -550 dtex have a warp, 135 to 203
having a basis weight of g / m ^2, blast from the electric arc while providing a high degree of comfort to the wearer, woven suitable for use in clothing having resistance to heat and radiant energy
Thing . 2. A twill weave having a woven fabric composition of 2 × 1 or 3 × 1.
And the weft consists of 100% flame-resistant cotton yarn
The woven fabric according to claim 1, characterized in that: 3. A fabric having a 3 × 1 left-twisted twill weave.
The woven fabric according to claim 2, wherein