JPS61186521A - Flameproof yarn - Google Patents

Abstract

PURPOSE:The titled yarn having high knot strength, improved spinning properties, wear resistance and flameproofing, obtained by adding a flame-retardant compound having dehydrating carbonization ability to flameproofing yarn of polyacrylonitrile having limited degree of flameproofing. CONSTITUTION:Flameproofing yarn of polyacrylonitrile having limit oxygen index (LOI for short) prescribed by JIS-K7201 of 21-35is blended with >=5wt%, preferably 10-20wt% flame-retardant compound having dehydrating carbonization ablity or organic halogen compound (bromine compound preferably hexabromobenzene, etc.) containing >=0.5 halogenating ratio, to give the aimed yarn. The flameproofing yarn having 21-35 LOI is provided with the flame- retardant compound or the halogen compound by immersing the yarn in a treating solution containing the compound.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to flame-resistant fibers with high knot strength, excellent spinnability, and abrasion resistance.

(Prior art) Traditionally, asbestos has been mainly used in fields that require flame resistance and heat resistance, but in recent years, carbon fibers and flame-resistant fibers have replaced asbestos due to their excellent flame and heat resistance. It is beginning to be used.

Among these, flame-resistant fibers are attracting attention because they have a low specific gravity and are flexible. but,
This fiber has the disadvantages of low knot strength and brittleness, and is extremely fluffy during weaving, and has very low strength and abrasion resistance after being made into a fabric, making it impractical. there were.

Such flame-resistant fibers include A1 compound, Fe compound, P
JP-A No. 59/1989 discloses that acrylonitrile-based fibers and m-fibers are treated in an aqueous solution prepared by mixing trace amounts of the three compounds to make them flame-resistant, thereby forming flame-resistant fibers with a limiting oxygen index of 45 or more.
This is proposed in the publication No.-76927. Although this fiber has flame resistance, its strength is low and the drawback of brittleness has not been solved.

(Problems to be Solved by the Invention) The present invention improves such conventional drawbacks, has high knot strength,
The present invention provides flame-resistant fibers with excellent spinnability and abrasion resistance.

The flame-resistant fiber of the present invention is unique in that it exhibits not only the above properties but also excellent flame resistance with a limiting oxygen index of 35 or more.

(Means for solving the problem) The limit oxygen index specified in JIS-7201 is 21~
The flame-resistant polyacrylonitrile fiber of No. 35 is a flame-retardant compound having dehydration carbonization ability or a halogenation rate of 0.
A flame-resistant fiber containing 5% by weight or more of at least one organic halogen compound of 5 or more.

The limiting oxygen index (hereinafter referred to as LOI) as used in the present invention is defined by JIS-7201, and is an index that is a measure of the degree of flame resistance and flame resistance performance. The measurement method is as follows.

' Wrap about 1 g of the measurement sample around a wire with a diameter of about Q and 3 mm as a support, make it into a string with a diameter of about 7 mm, and tie it vertically by 15 mm.
0111m frame and set it inside the combustion cylinder. Next, a mixed gas of oxygen and nitrogen was added to the mixture at 11.4
α/min, after approximately 30 seconds, the upper end of the sample is ignited and the minimum oxygen flow rate (A) required for the sample to continue burning for 3 minutes or more or for a combustion length of 50 mm or more after ignition. And the nitrogen flow at that time! (B). The ratio of the oxygen flow rate to the total flow rate of the mixed gas is the LOI.

LOI = [A/ (A + B)] The higher the value of x100-LOI, the more advanced the flame resistance is, and the higher the flame resistance performance.

The flame-resistant fiber as used in the present invention needs to be a specific fiber having the above-mentioned LOI in the range of 21 to 35.

Acrylonitrile fiber (PAN) with LOI less than 21
However, flame resistance is poor and no improvement in flame resistance can be expected. Furthermore, with PAN having an LOI exceeding 35, it is not possible to obtain a satisfactory nodule strength, and a dramatic improvement in the LOI value cannot be achieved.

The PAN referred to in the present invention is a PAN that is usually used as a precursor, and contains at least 80% of acrylonitrile.
It is a polymer or copolymer containing 5 mol% or more, preferably 95 mol% or more.

Such copolymerization components include, for example, allyl carboxylic acids and their esters such as acrylic acid, methacrylic acid, itaconic acid, methyl acrylate, and methyl methacrylate, as well as hydroxyethyl acrylic acid,
Hydrous acid group carboxylic acids and their esters such as hydroxyethyl acrylate and hydroxyethyl methacrylate, and vinyl group-containing compounds such as vinyl chloride, vinylidene chloride, α-chloroacrylonitrile, hydroxyacrylonitrile, and sodium allylsulfonate. can give.

There is no limit to the fineness of such PAN, but it generally only needs to be 0.5 d or more, and 1 to 15 d is particularly used.

The flame-resistant fiber of the present invention is characterized in that the knot strength of the single fiber is 0°9q or more, roughly 1.0g or more. That is, this fiber exhibits excellent performance in abrasion resistance and bending resistance.

The flame-resistant fiber of the present invention has an LOI of at least 35, roughly 40, while also having the above-mentioned strong performance improvement.
In particular, it is distinctive in that it achieves a dramatic improvement in flame resistance of 45 or more.

Such fibers can be achieved by adding 5% by weight or more of at least one kind of a compound having dehydration carbonization ability or an organic halogen compound having a halogenation rate of 0.5 or more to the above-mentioned specific flame-resistant fiber.

Examples of flame-retardant compounds having dehydration carbonization ability include, but are not limited to, 811m compounds, sulfamic acid compounds, guanidine compounds, melamine compounds, and phosphorus compounds.

Among these, flame-retardant compounds containing halogen and/or phosphorus as active ingredients are preferred.

Among such flame-retardant compounds, inorganic compounds or acid compounds are particularly preferred. For example, v! A acid, ammonium borate, borax, guanidine sulfamate, orthophosphoric acid, condensed phosphoric acid, ammonium phosphate, guanylurea phosphate, guanidine phosphate, melamine phosphate, zinc chloride, zirconium chloride, aluminum chloride ammonium bromide, etc. can give. Among such compounds, guanidine compounds are particularly preferred because they exhibit excellent stability.

An organic halogen compound having a halogenation rate of 0.5 or more is one in which the value obtained by dividing the total amount of halogen atoms contained by the molecular weight of the compound (halogenation rate) is 0.5 or more.

Examples of such compounds include halogen compounds such as hexachlorocyclododecane, pentachlorodiphenyl ether, hexabromocyclododecane, bentab, romodiphenyl ether, decabromodiphenyl ether, and hexabromobenzene. Among these, bromine compounds are preferred.

Such a compound is preferably contained in an amount of 7 to 30% by weight, particularly preferably 10 to 20% by weight, thereby reducing the LO
A synergistic improvement in I as well as nodule strength is achieved. Here, as for the form of inclusion, the form of attachment has the characteristic that it is particularly easy to achieve the effects of the present invention.

The fiber of the present invention is a PAN oxidized to the specific LOI.
This is achieved by applying the compound to the surface of the substrate by means of impregnation, padding, coating, or the like with a conventional processing agent solution.

The PAN-based flame-resistant fiber of the present invention is formed by a conventional method. That is, a normal PAN precursor is replaced with air,
It is formed by performing oxidation treatment in S02 or other oxidizing gas at a temperature of 200 to 300° C. for 10 minutes or more. The degree of flame resistance at this time is controlled to a specific range of LOI of 21 to 35, preferably 23 to 30. In other words, it is characterized by suppressing the degree of flame resistance.

After applying the compound, it is heated and dried if necessary.

Although the flame-resistant fiber thus obtained is a PAN with a low degree of flame resistance, it has excellent flame resistance, and simultaneously improves knot strength, abrasion resistance, and bending resistance.

(Example) Example 1 An acrylic copolymer consisting of 99.2 mol% acrylonitrile, 0.4 mol% itaconic acid, and 0.4 mol% sodium allylsulfonate was wet-spun into a single fiber by a conventional method. A fiber with a fineness of 2.3 d was obtained.

The obtained PAN was hung in a free state on an iron frame in the form of a windshield, and oxidized in air at 250°C. Flame-resistant yarns with different LOIs were formed by changing the oxidation conditions.

Each of the obtained PANs having various LOIs was provided with 10% by weight of phosphoric acid in terms of solid content.

These results were evaluated by tensile strength, knot strength and LOI.

The LOI in the table is 7021 according to JIS'- defined in the main text.
This is in accordance with. Furthermore, the tensile strength and knot strength are data for one single yarn.

From the results in Table 1, it is clear from the data on flame-resistant fibers that fibers whose original flame-resistant fibers have an LOI of 21 to 35 have high knot strength and tensile strength, and have improved flame resistance.

Examples 5 to 12 Using the flame-resistant fiber of Example 2 with an LOI of 25, various flame-retardant compounds were added in an amount of about 10% by weight, and the LOI of the obtained flame-resistant fiber was evaluated.

The results are shown in Table 2.

The X conversion rate in the table means the halogenation rate.

From the table, it can be seen that organic halogen compounds with a halogenation rate of 0.5 or more and compounds having dehydration carbonization ability have a large effect of improving flame resistance performance. In particular, it can be seen that compounds having dehydration carbonization ability have a large effect of improving LOI.

Examples 13 to 15 A guanidine phosphate aqueous solution was applied to the flame-retardant fiber of LOI 25 obtained in Example 2 with varying amounts of adhesion. The LOI of this fiber was measured. The results are shown in Table 3.

It can be seen from the table that the object of the present invention cannot be achieved if the content of the flame retardant compound is less than 5% by weight.

(Effects of the Invention) The present invention provides a flame-resistant fiber with high knot strength and excellent spinnability, abrasion resistance, and bending resistance. The flame-resistant fiber of the present invention simultaneously achieves the above properties and excellent flame resistance.

Claims (1)

[Claims] (1) Polyacrylonitrile flame-resistant fibers with a limiting oxygen index of 21 to 35 as defined in JIS-K7201 are made of flame-retardant compounds with dehydration carbonization ability or organic halogen compounds with a halogenation rate of 0.5 or more. A flame-resistant fiber containing 5% by weight or more of at least one kind.