JPH02221432A - Fine denier core spun yarn - Google Patents

Abstract

PURPOSE: To obtain a fine denier bicomponent corespun yarn for forming a fine texture useful for a fireproof safety wear by covering a core composed of a heat-resistant fiber with a wrapper composed of a cold-resistant fiber. CONSTITUTION: A core composed of an aramid fiber, a polybenzimidazole fiber or a heat-stabilized/oxidized polyacrylonitrile fiber is covered with a wrapper composed of a cold-resistant fiber (e.g. cotton, wool, polyester fiber or modacrylic fiber). The outer surface of the yarn has the appearance and general properties of the cold-resistant fiber. A fireproof safety wear having the appearance, dyeability, comfortableness, etc., of conventional woven fabric can be produced by the use of the yarn.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates generally to fine-grained bicomponent core-spun yarns and methods of forming core-spun yarns for forming textiles useful in the manufacture of fire-resistant safety apparel, and more particularly to the production of heat-resistant fibers. The present invention relates to a corespun yarn having a core and a core wrapper of cold resistant fibers surrounding and covering the core.

It is generally known to form heat resistant fabrics from various types of yarns. For example, dangerous industrial work clothes,
Firefighter uniforms and military protective clothing have been formed from fabricated fabrics of yarns formed from non-synthetic fibers such as cotton or wool.

These fabrics are then generally treated with conventional halogen- and/or phosphorus-based flame retardant chemicals.

However, garments formed from this type of fabric have a limited wear life and are heavier than flame retardant garment fabrics, typically chemical treatments adding about 15-20% to the weight of the fabric. When this type of fabric burns, it forms brittle chars that separate as the fabric moves.

Nomex is known to form fire-resistant safety garments consisting of fabricated fabrics of yarns formed entirely from non-flammable or heat-resistant fibers or blends of non-flammable fibers such as Nomex, Kevlar or Pal. ing. Although these fabrics exhibit thermal stability, they are significantly more expensive to manufacture and do not have the comfort, moisture absorption, and dyeability of fabrics formed from natural fiber yarns.

U.S. Pat. Nos. 4,381,639, 4,500,593 and 4,670,327 disclose yarns for forming heat resistant fabrics in which a core of continuous glass filaments is coated with a layer of heat resistant aramid fibers. However, the yarns and fabrics disclosed in these patent documents are significantly more expensive to manufacture due to the extremely high cost of the fibers required to produce these yarns and fabrics. Also, since the yarns and fabrics disclosed in these patent documents have the surface properties of aramid fibers, these fabrics have the dyeability of fabrics formed from conventional natural fibers such as cotton, wool, etc. and do not have desirable surface properties for comfort.

U.S. Pat. No. 4,331,729 discloses a heat resistant fabric formed from yarn having a core of carbon filaments and a cover of aramid fibers. The yarns and heat resistant fabrics disclosed in this patent also have similar drawbacks as pointed out in the above description of prior art patent documents.

Pending U.S. Patent Application No. 288,682, filed December 22, 1988, discloses ternary core spun yarns for forming fabrics useful in making fire resistant safety apparel. Three-component core span in the above application
The yarn has a core of heat resistant fibers, a core wrapper of cold resistant fibers and an outer sheath of cold resistant fibers. This three-component core spun yarn was spun on an 0REF friction spinning machine, and the finest yarn count obtained using this machine was 14.
/l cotton count (equivalent to 380 denier). Although this ternary core-spun yarn provides excellent fire resistance, dyeability, and comfort to fabrics formed from this yarn, it is often desirable to create microstructured fabrics of core-spun yarn with a fine count. .

It is therefore an object of the present invention to provide finely divided fibers that are useful in producing fire-resistant safety garments that have the look, feel, dyeability and comfort of conventional types of textiles formed from conventional natural fibers and without fire resistance. The present invention provides a fine-grained bicomponent core-spun yarn for forming tissue fabrics.

The fine-grained bicomponent corespun yarns of the present invention have a core of heat resistant fibers and a core wrapper or outer sheath of cold resistant fibers surrounding and covering the core. The heat-resistant fibers forming the core are aramid fibers, such as Kevlar or Nomex, or polybenzimidazole fibers, such as FBI, or heat-stabilized/oxidized polyacrylonitrile fibers, such as P manufactured by RK Textiles.
anox■ and Asahi Chemical Company La
It is 5tan■. The cold-resistant fibers of the core wrapper can be natural or synthetic fibers, such as cotton, wool, polyester,
Modacrylic fibers or blends of these fibers.

The fineness core spun yarn of the present invention is 22/1 (242
denier), 20/H266 denier) and 18/1
It is manufactured with a fine count of (295 denier).

The core of heat resistant fibers comprises about 20-25% of the total weight of the corespun yarn and the core wrapper of cold resistant fibers comprises about 80-75% of the total weight of the corespun yarn. Preferably, the core heat-resistant fibers constitute about 20% of the total weight and the core wrapper of cold-resistant fibers makes up about 80% of the total weight.

The core spun yarn is produced using Murata air jet spinning equipment (M
JS), into which the heat-resistant fibers of the core and the cold-resistant fibers of the core wrapper are fed together through the artificial end of a wrapper-type feeding device. The fibers are then passed through a drawing process through air jet nozzles in which air streams flow in opposite directions, and then wound into a winding package.

Since the air jet nozzle surrounds and coats the core with a core wrapper of cold-resistant fibers, the resulting yarns and fabrics have the surface properties of the cold-resistant fibers forming the core wrapper, but the yarns are subject to twist, torque and Even if it has activity, it has very little activity.

When woven fabrics formed from the fine-grained core-spun yarns of the present invention are exposed to flame and high heat, the core sheath of cold-resistant stable fibers surrounding and covering the core chars and burns, but remains in position around the glass fiber core. to provide a thermal insulation barrier.

The heat-resistant fiber core remains intact after the cold-resistant organic fiber core wrapper burns, and the core forms a lattice on which carbides remain to block the flow of oxygen and other gases. Meanwhile, the remaining support lattice provides the structure that the fabric remains intact after the core wrapper of low-temperature-resistant organic fibers burns and carbonizes.

The core spun yarns of the present invention have a low percentage by weight of expensive heat resistant fibers. Preferably about 20% by weight, the corespun yarns of the present invention can be produced at significantly more economical prices than refractory fabrics formed from yarns having a large proportion by weight of expensive refractory fibers. . For example, core heat resistant fibers cost about 9 to IO dollars/bond, and core wrapper cotton fibers cost about 60 to 80 cents/pound. Thus, by using approximately 80% cotton fibers, significant savings in manufacturing cost of the core spun yarns of the present invention are realized.

When textiles formed from the core-spun yarns of the present invention are exposed to high heat and flame, the core wrapper fibers become carbonized but remain in position around the heat-resistant core to provide a thermally insulating barrier. This provides an insulating air layer between the skin and the fabric. This property is important in the fire scene, where firefighters wearing shirts or hoods made from this fabric will be able to maintain their original strength even as the core wrapper fibers become carbonized. Thermal protection continues due to the insulating air layer between clothing and skin.

Fabrics woven or knitted with the core-spun yarns of the present invention can be dyed and printed, and are generally treated with conventional flame retardants in a manner similar to the flame retardant treatments applied to fabrics made from 100% cotton fibers. Can be treated with flame retardant chemicals. However, since the heat resistant fiber core does not absorb flame retardant chemicals, the weight added to the fabric by flame retardant treatment is significantly reduced to about 10% to 12%. Fabrics formed from core spun yarns of the present invention do not melt. No dripping, no afterflame or residual dust when burned.

The exterior of the carbonized fabric maintains the flexibility and integrity of the unburned portion of the fabric.

Next, the present invention will be described by way of examples with reference to the drawings.

The fine core spun yarn of the present invention, shown at 10 in FIG. 1, comprises a heat resistant fiber core 11 and a cold resistant core wrapper 12 surrounding and covering the core 11. As shown in Figure 1, the heat-resistant fiber of the core 11 is generally a core spun yarn.
The core rough par 1 extends in the axial direction or length direction of O.
The main portion of the cold-resistant fibers of No. 2 extend helically around the core 110. Small portions of the cold-resistant fibers of the core roughper 12 separate to form a tangle wrapper that wraps helically around the main portion of the fibers, as shown at 13. The cold-resistant staple fiber core wrapper 12 surrounds and covers core II so that the outer surface of the yarn has the appearance and general characteristics of the cold-resistant stable fiber forming the core sheath 12.

The heat-resistant fibers of the core 11 are mainly aramid fibers such as Kevlar and Nomex, polybenzimidazole fibers such as PBI, or Pa manufactured by RK Textiles.
nox% and Asahi Chemical Company La5t
Heat stabilized/oxidized polyaquaroni like an■) IJ
fibers or mixtures or blends of these fibers. The cold-resistant fibers of the core rough par 12 can be either natural or synthetic fibers, such as cotton, wool, polyester, modacrylic, rayon, or blends of these fibers.

The heat-resistant fiber core 11 constitutes about 20-25% of the total weight of the core-spun yarn 10, and the cold-resistant fiber core rough 12 constitutes about 80-7% of the total weight of the core-spun yarn IO.
It constitutes 5%. The heat-resistant fiber core 11 accounts for approximately 2 of the total weight.
Preferably, the core wrapper 12 of cold-resistant fibers comprises about 80% of the total weight.

Core 11 is preferably formed entirely of aramid fibers or a blend of these fibers and polybenzimidazole fibers. Core rough par 12 is core 11
The fibers forming the yarn are completely hidden and hidden from view in the fabric made from this yarn, surrounding and covering the core 11.

As mentioned above, the core spun yarn 10 of the present invention
Preferably, it is produced on a Murata air jet spinning apparatus of the type outlined in the figure. Murata air jet spinning equipment is disclosed in a number of patents, including U.S. Pat. As shown schematically in FIG.
1 along with a sliver of cold-resistant staple fiber 12 to form a core wrapper surrounding and covering the core. The fibers are then passed through a set of drawing rolls 16, a first fluid swirling air jet nozzle 17 and a second fluid swirling air jet nozzle 18. The spun yarn,
A combination of delivery rolls 19 pulls the fluid from the second swirling air jet nozzle 18 and winds it into a winding package, not shown. The first and second fluid swirl nozzles or air dienes 17.18 are configured to provide swirling fluid flows in opposite directions, as outlined in FIG. The action of 17.18 causes a small portion of the staple fiber to separate and wrap around the unseparated staple fiber, causing the wound staple fiber to tightly seal the core sheath 12 to the core 11. The core 11 is surrounded and covered.

Next, an example of the core spun yarn produced according to the present invention will be shown, but the present invention is not limited thereto.

A 0.50 bank roving (r
One end of the oving) was fed to the end of the trumpet-shaped population 15. Also, at the same time one end of 100% carded cotton sliver was fed into the end of the wrapper shape 15 giving the necessary weight to reach 80% of the total yarn weight. core 1
1 was fed onto the top of the cotton sliver 12 to spin cotton fibers around the core. Next, the fine core spun yarn obtained by this air jet spinning method was knitted into a fabric 20 having a plain knit jersey structure as shown in FIG. The core spun yarn 10 formed a continuous course of netted loops in the fabric 20.

This knitted fabric 20 is particularly suitable for use in forming protective hoods or undergarments for firefighting soils and is dyed and subjected to an essentially fire-retardant chemical treatment and then, if required, conventional durable treatments. Finished with pressure resin.

This fabric had the feel and surface properties of a similar type of knitted fabric made from 100% cotton fibers, while possessing desirable fire resistance properties not present in knitted fabrics made entirely of cotton fibers. .

This fire-resistant knitted fabric is certified by the National Fire Department, including resistance to vertical combustion for 12 seconds against Bunsen burner flames.
When tested using the National Prepension Association Test Method (NFPA 701), this knitted fabric has a
．． It showed a char length of less than 81 cm (1.5 inches) and no afterflame or residue. US Federal Test Method 5905
According to the company, when exposed to two 12-second exposures to a high-heat flux butane flame, a similar type of knitted fabric of similar weight and construction made entirely of cotton fibers and treated with fire-resistant chemicals has a vertical burn rate of 45%. It had an afterflame of 0 seconds with 22% depletion, compared to 22% depletion and an afterflame of 6 seconds. The textile carbonized area remains flexible and intact throughout the entire combustion test;
It showed no brittleness, melting or fabric shrinkage. The cotton fiber core wrapper burned and carbonized, but remained in place surrounding the heat-resistant Kevlar fiber core to provide a thermally insulating barrier, and the Kevlar core provided a matrix or lattice that prevented fabric breakdown. The insulating barrier prevented flames from penetrating the fabric and reaching the skin of the person wearing the hood.

In textiles used to form fire-resistant safety garments, as described above, the core-spun yarn 10 is comprised of two components:
That is, the heat-resistant fibers mainly extend in the axial or longitudinal direction of the yarn, the core 11, and the cold-resistant fibers mainly extend in the core 1.
The fiber has a core rough part 12 which extends mainly around the core 11 in a helical direction and surrounds and covers the core 11. The heat resistant fibers of core 11 are selected from the group consisting essentially of aramid fibers, polybenzimidazole) fibers and heat stabilized/oxidized polyacrylonitrile fibers, and core 11 exposes the fabric formed from this yarn to a high temperature flame. Even when exposed, it remains intact. The fibers of the core rough par 12 surround and cover the core 11. The fibers of core wrapper 12 provide the desired surface properties to fabrics formed from these corespun yarns. When a fabric formed from the core spun yarns of the present invention is exposed to a high temperature flame atmosphere, the fibers of the core rough par 12 burn and carbonize, but remain in position around the core 11 and have approximately the same flexibility and flexibility as an unburned fabric. Remain in its original form.

[Brief explanation of the drawing]

FIG. 1 is a partial enlarged view of the core-spun yarn of the present invention with a portion of the core roughness removed; FIG. 2 is a portion of the Murata air jet spinning apparatus of the type used to form the fine-grained core-spun yarn of the present invention. FIG. 3 is a partially enlarged view of the knitted fabric of the core spun yarn shown in FIG. 1. 10...Core span Yarn 11...Core 12...Core wrapper (or core sheath) 15.
...Trumpet-shaped population 16...Stretching roll 17...
- First fluid swirling air jet nozzle 18...Second fluid swirling air jet nozzle 19...combination delivery roll

Claims (1)

[Claims] 1. A fine-grained core spun yarn for forming a fire-resistant safety garment comprising essentially aramid fibers, polybenzimidazole fibers and heat stabilized/
A fine-grained core spun yarn characterized by having a core made of heat-resistant fibers selected from the group consisting of oxidized polyacrylonitrile fibers, and a core wrapper of cold-resistant fibers surrounding and covering the core. 2. The core of heat-resistant fibers constitutes about 20-25% of the total weight of the core-spun yarn, and the core wrapper of cold-resistant fibers constitutes about 80-75% of the total weight of the core-spun yarn. The fine-grained core-spun yarn according to claim 1. 3. The core of heat-resistant fibers constitutes about 20% of the total weight of the core-spun yarn, and the core wrapper of cold-resistant fibers constitutes about 80% of the total weight of the core-spun yarn. The fine-grained core-spun yarn according to claim 2. 4. The fine-grained core spun yarn according to claim 1, wherein the core is made of aramid fiber. 5. The fine-grained core spun yarn according to claim 1, wherein the core wrapper is made of cotton fiber. 6. The fine-grained core spun yarn according to claim 4, wherein the core is made of Kevlar fiber.