JPH08269843A - Fabric excellent in flame resistance - Google Patents

Abstract

PURPOSE: To obtain a flame-resistant fabric by specifying a blending ratio of a colorable flame-retardant fiber and a polybenzal fiber, having slight reduction in strength after being brought into contact with a flame, excellent in appreciating properties and comfortableness in wearing. CONSTITUTION: This fabric is obtained by mixing a colorable flame-retardant fiber with a polybenzal fiber in a weight ration of 97/3-80/20 and made into a fabric. The fabric has flame retardance of <=2cm carbonization distance evaluated by fiber product flammability test method A-4 of JIS L1091.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fabric having excellent flame resistance, and more particularly to a fabric useful for clothing used in the industrial field where fire hazard is predicted and in the fire field.

[0002]

2. Description of the Related Art As a clothing material for protecting oneself from danger such as a fire, a cloth made of many flame-retardant fibers has been put into practical use. In addition to the conventionally used flame-retardant cotton, wool, acrylic, rayon, etc., meta-aramid fiber is widely used due to its excellent performance. Further, as disclosed in JP-A-1-221537, attempts have been made to improve the perforation property during flame contact by mixing a small amount of para-aramid fiber with meta-aramid fiber.

[0003]

As mentioned above, although a small amount of para-aramid fiber is mixed with meta-aramid fiber to improve the perforation at the time of flame contact, the fabric after the flame contact has a large decrease in strength. However, it was unsatisfactory in terms of protecting the body during evacuation in the event of a fire. The present invention was devised in view of the current state of the art, and an object thereof is to provide a flame resistant fabric which has a small decrease in strength after flame contact and is excellent in aesthetics and comfort due to coloring. It is in.

[0004]

In order to achieve the above-mentioned object, the present inventor has conducted earnest studies on a material that suppresses the reduction of strength particularly after flame contact, and as a result, completed the present invention. That is, the present invention is a cloth made of a mixed yarn of a colorable flame-retardant fiber and a polybenzazole fiber, and the mixing ratio of the colorable flame-retardant fiber and the polybenzazole fiber is 97/3 by weight.
It is a fabric excellent in flame resistance, which is characterized in that it is 80/20.

Polybenzazole fiber is a fiber made of polybenzazole (PBZ) polymer. Polybenzazole (PBZ) is polybenzoxazole (PBZ)
O) homopolymer, polybenzothiazole (PBT) homopolymer, and random, sequential or block copolymers of PBO and PBT. Here, polybenzoxazole, polybenzothiazole and their random, sequential or block copolymers are described, for example, in Wolfe et al.
stalline Polymer Compositions, Process and Pr
oducts "U.S. Pat. No. 4,703,103 (1987, 1
(27th October), "Liquid Crystalline Polymer Compo
sitions, Process and Products "US Patent No. 45
No. 33692 (August 6, 1985), "Liquid Cry
stalline Poly (2,6-Benzothiazole) Composit
ions, Process and Products "US Patent No. 4533
No. 724 (August 6, 1985), "Liquid Crystal
line Polymer Compositions, Process and Produc
ts "U.S. Pat. No. 4,533,693 (August 6, 1985)
Sun), Evers et al., "Thermooxidatively Stable Arti
culated p- Benzobisoxazole and p- Benzobist
hiazole Polymers "U.S. Pat. No. 4,359,567 (1
November 16, 982), "Method for ma by Tsai et al.
"King Heterocyclic Block Copolymer" US Patent No. 4
No. 578432 (March 25, 1986).

The structural unit contained in the PBZ polymer is preferably selected from lyotropic liquid crystal polymers. The PBZ polymer used in the present invention preferably consists essentially of monomer units selected from the following structural formulas (a)-(h), and more preferably consists essentially of structural formulas (a)-(c). It consists of selected monomer units.

[0007]

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[0008]

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[0009]

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[0010]

[Chemical 4]

[0011]

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[0012]

[Chemical 6]

[0013]

[Chemical 7]

[0014]

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Suitable solvents for forming the dope of PBZ polymer include cresol and non-oxidizing acids capable of dissolving the polymer. Examples of suitable acid solvents include polyphosphoric acid, methanesulfonic acid and concentrated sulfuric acid or mixtures thereof. Further suitable solvents are polyphosphoric acid and methanesulfonic acid. The most suitable solvent is polyphosphoric acid.

From the viewpoint of spinnability and productivity, the polymer concentration of the solution is preferably at least 7% by weight, more preferably at least 10% by weight, and most preferably at least 14% by weight. The maximum concentration is limited by practical handling characteristics such as polymer solubility and dope viscosity. Due to these limiting factors, the polymer concentration usually does not exceed 20% by weight.

The polymer, copolymer or dope suitable for the present invention is synthesized by a known method. Eg Wol
fe et al., US Pat. No. 4,533,693 (August 6, 1985), Sybert et al., US Pat. No. 4,772,678 (19).
September 20, 1988), Harris et al., U.S. Pat.
No. 350 (July 11, 1989). According to US Pat. No. 5,089,591 to Gregory et al. (February 18, 1992), the PBZ polymer has a high molecular weight at a high reaction rate in a dehydrating acid solvent at a relatively high temperature under a high breaking condition. It is possible.

The colorable flame-retardant fiber used in the present invention is a fiber colored with a dye or pigment by a so-called so-called dyeing method in the fiber manufacturing process, or can be colored with various dyes after the fiber manufacturing process. Fiber and L
A fiber having an OI value of 25 or more. For example, it refers to natural fibers such as cotton and wool that are imparted with flame retardancy, acrylics, rayon fibers, and aromatic polyamide fibers that are imparted with flame retardancy. Aromatic polyamide fibers are those generally called meta-aramid fibers having a basic structure of polymetaphenylene isophthalamide polymer, and may be improved by copolymerization or blending, for example, JP-A-55-2.
Aromatic polyamide polymers such as those described in JP-A No. 1406, JP-A-55-21406 or JP-A-55-29516 may be mixed.
Specifically, Nomex (Dupont), Conex (Teijin), Apiel (Unitika), Kermer (Kanebo)
Known as the trademark fiber such as.

The blended yarn of the colorable flame-retardant fiber and the polybenzazole fiber in the present invention can be obtained by a known method. For example, there are a method of mixing before carding and a method of making a sliver and then mixing. It is necessary that the mixing ratio of the above blended yarn is 97/3 to 80/20 in weight ratio of the flame-retardant fiber and the polybenzazole fiber which can be colored. If the mixing ratio of the polybenzazole fiber is less than 3% by weight, the strength retention after flame contact is so small that the desired performance fabric cannot be obtained. If the mixing ratio of the polybenzazole fiber exceeds 20% by weight,
The desired color tone cannot be obtained even when the colorable flame-retardant fiber is colored. Further, the texture of the cloth is deteriorated, which causes a problem in comfort and the like.

The blended yarn thus obtained is processed into woven or knitted fabrics having various structures and used in the intended field as a fabric having excellent flame resistance. The tissue is selected according to the purpose of use and is not particularly limited. The fabric weight is preferably 1
00 g / m ² or more, more preferably 200 g / m ²
m ² or more.

The fabric of the present invention is characterized in that it has a high strength retention after contact with flame. Specifically, JIS L
The carbonization distance evaluated by the A-4 method (vertical method) of the flammability test method for 1091 textiles is 2 cm or less. JI
The measurement of the carbonization distance defined in S is defined by the distance torn from the lower end of the sample when a constant load is applied to the sample after the flame contact, and the smaller the distance is, the strength retention ratio after the flame contact. Can be said to be large.

[0022]

EXAMPLES Examples and comparative examples will be shown below, but the present invention is not limited to these as long as the gist of the present invention is not exceeded.

Examples 1 to 3 A spinning dope prepared by dissolving 14% by weight of cis-polybenzoxazole having an intrinsic viscosity of 30 dl / g in polyphosphoric acid was used.
It was extruded from a nozzle of 334 holes having an orifice diameter of 22 mm at a temperature of 160 ° C. and a single hole discharge amount of 0.122 cc. The fibrous dope extruded from the nozzle is 22c
m air gap, pulled through it and passed through the coagulation bath adjusted to about 22 ° C, and traveling speed about 20
It was continuously washed with 5 or more pairs of rollers at 0 m / min, subsequently dried without being once wound, and after applying an oil agent for spinning, it was wound. The obtained fiber had a single fiber strength of 42 g / d and a single fiber denier of 1.5 d.
The obtained fiber was combined with a tow of 30,000 denier, crimped with a push-in crimper, and cut with a rotary cutter to obtain a polybenzoxazole staple having a fiber length of 44 mm.

The obtained PBO staple and LOI value are 3
A flame-retardant polynodix staple (trade name: Toughban, manufactured by Toyobo Co., Ltd.) of 0 was changed in mixing ratio (weight ratio) as shown in Table 1 to produce a 20th-count mixed yarn. Using each of the obtained blended yarns of each mixing ratio, a basis weight of 200 g
A plain weave fabric was woven with a target of / m ² . The obtained cloth was evaluated for the strength retention after flame contact from the carbonization distance according to the A-4 method (vertical method) of the flammability test method for JIS L 1091 fiber products. The dyeability is Kayanc manufactured by Nippon Kayaku Co., Ltd.
ion Navy E-CM 6% owf and anhydrous Glauber's salt 67g / l,
Sodium carbonate 20g / l at 80 ° C for 60 minutes, bath ratio 1:20
Dyeing was carried out under the conditions of, and evaluation was made based on apparent dyeing unevenness. In each of Examples 1 to 3, the strength retention after flame contact and the dyeability were excellent.

Examples 4 to 6 The mixing ratio (weight ratio) of the polybenzoxazole staple obtained in Example 1 and the meta-aramid fiber having a LOI value of 28 (trade name: Nomex, manufactured by DuPont) is shown in Table 1. To produce a 20th count blended yarn. The weight per unit area of 200
A plain weave fabric was woven with a target of g / m ² . The obtained cloth was evaluated for the strength retention after flame contact from the carbonization distance according to the A-4 method (vertical method) of the flammability test method for JIS L 1091 fiber products. In each of Examples 4 to 6, the strength retention rate after the contact with flame was excellent.

Comparative Examples 1 to 3 The mixing ratio (weight ratio) of the polybenzoxazole staple obtained in Example 1 and the flame-retardant polynodix staple having a LOI value of 30 (trade name Toughban, manufactured by Toyobo) is shown in Table 1. A 20th count blended yarn was produced by changing as shown. A plain weave fabric was woven by using each of the obtained blended yarns having different mixing ratios with a target weight of 200 g / m ² . The obtained cloth was evaluated for the strength retention after flame contact from the carbonization distance according to the A-4 method (vertical method) of the flammability test method for JIS L 1091 fiber products. The dyeability is Nippon Kayaku Co., Ltd.
Made Kayacion Navy E-CM 6% owf and anhydrous Glauber's salt 6
7 g / l and 20 g / l of sodium carbonate were dyed and processed under the conditions of 80 ° C., 60 minutes and a bath ratio of 1:20, and evaluated by an apparent dyeing unevenness.

In Comparative Examples 1 and 2, the carbonization distance after flame contact was very large because the mixing ratio of the polybenzazole fiber was too small. Further, in Comparative Example 3, since the mixing ratio of the polybenzazole fiber is too large, the uneven dyeing is large and the aesthetic appearance is deteriorated.

Comparative Examples 4, 5 Staples of meta-aramid fiber (trade name: Nomex, manufactured by DuPont) and para-aramid fiber (trade name: Kevlar 29, manufactured by DuPont) having LOI values of 28 were changed as shown in Table 1. A 20th count blended yarn was produced. Using each of the obtained blended yarns, a plain weave fabric was woven with a target weight of 200 g / m ² . The obtained cloth is JIS
The strength retention rate after flame contact was evaluated from the carbonization distance according to the A-4 method (vertical method) of the flammability test method for L 1091 textiles. Since Comparative Examples 4 and 5 do not contain polybenzazole fiber, the carbonization distance is very large.

[0029]

[Table 1]

[0030]

The fabric of the present invention has a specific mixing ratio (weight ratio).
Since it is composed of a mixed yarn of the flame-retardant fiber and the polybenzazole fiber, which can be colored, a flame-resistant fabric having a large strength retention after flame contact and being excellent in aesthetics and wearing comfort by coloring can be obtained.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location D03D 15/00 D03D 15/00 D

Claims (2)

[Claims] 1. A fabric composed of a mixed yarn of a colorable flame-retardant fiber and a polybenzazole fiber, wherein the mixing ratio of the colorable flame-retardant fiber and the polybenzazole fiber is 97/3 by weight.
A fabric excellent in flame resistance, characterized in that it is -80/20. 2. A fabric excellent in flame resistance according to claim 1, which has a carbonization distance of 2 cm or less evaluated by A-4 method (vertical method) of the flammability test method for JIS L 1091 textiles.