JPS5951604B2 - Manufacturing method of flame retardant polyamide fiber - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing flame-retardant polyamide fibers.

Polyamides, especially nylon 6 and nylon 66, are widely used as fibers and other molding materials because of their excellent mechanical properties, good dyeability, and beautiful appearance.

However, polyamides have the disadvantage of being easily combustible, which limits their use. Conventionally, as a method of imparting flame retardancy to polyamide, a method has been known in which the surface of a polyamide molded article, for example, polyamide fiber, is treated with a flame retardant such as thiourea.

However, in order to obtain a sufficient flame retardant effect using this method, it is necessary to increase the amount of flame retardant applied, which not only significantly impairs the appearance and texture of the product, but also causes poor durability of the flame retardant effect. It has the following drawback. As a method of eliminating such drawbacks, various attempts have been made to add flame retardants internally to polyamide before molding the polyamide.

However, the flame retardants that have been proposed so far do not have a sufficient flame retardant effect on polyamides, and require a large amount of addition to improve the effect. Moreover, since many flame retardants have reactivity with polyamide, adding a large amount of flame retardant is accompanied by undesirable phenomena such as significant decomposition, foaming, gelation, and coloring of polyamide, and the inherent physical properties of polyamide and the commercial value is significantly impaired. For example, special public service
Publication No. 546 describes a nuclear brominated diphenyl compound as a flame retardant for polyamide, and it is said that this compound has excellent heat resistance and hardly deteriorates the polyamide even when mixed with polyamide and heated. According to additional experiments conducted by the present inventors, when nylon 6 is melt-spun with 10% by weight of hexaprom diphenyl ether among nuclear brominated diphenyl compounds, the deterioration of nylon 6 is caused by other halogens. Although it is certainly less compared to compounds,
Even so, the color tone was yellowish compared to unmodified nylon 6, and the flame retardancy of the obtained thread was also insufficient.

On the other hand, extremely large amounts (15-30% by weight) are used as flame retardants.
Polyamide blended with the above-mentioned nuclear halogenated aromatic compound exhibits relatively good flame retardancy, but this method impairs the inherent physical properties and commercial value of the polyamide, and also increases cost.

Furthermore, this type of polyamide has a very serious defect in that it generates a large amount of toxic halogen gas when it is burned. In order to compensate for these deficiencies, various flame retardant aids such as metal oxides have been investigated in order to reduce the amount of halogen flame retardant and to provide higher flame retardancy.

For example, antimony oxide is well known as a flame retardant aid for halogen flame retardants. However, this method requires adding several percent or more of insoluble antimony oxide to the polyamide.
This is a major technical obstacle in fiberization. That is, antimony oxide aggregates and causes clogging of the melt spinneret bag, or forms knots in the yarn, causing frequent spun yarn breakage and drawn yarn breakage, making it virtually difficult to make fibers. . As mentioned above, the conventionally known flame retardants for polyamides have various drawbacks, and the degree of difficulty increases dramatically when converting them into fibers, so they have never been put to practical use. is the current situation.

The purpose of the present invention is to overcome the various deficiencies of the prior art, and to produce polyamide fibers that have excellent flame retardant performance by incorporating a small amount of flame retardant without impairing the original excellent physical properties of polyamide. Another object of the present invention is to provide a method for manufacturing polyamide fibers industrially easily and inexpensively.

That is, the present invention provides a polyamide with the general formula (1) [wherein Group or carbon number 7-1
6 aralkyl group or nuclear halogenated aralkyl group, provided that halogen is chlorine and/or bromine, and R'' has 1 to 1 carbon atoms.
6 alkylene group), 1 is an integer of 2 to 6, and m is O or 1.

] 0.5 to 1% based on the weight of the polyamide fiber from which at least one type of nuclear halogenated aromatic compound is obtained.
5%, and at least one carboxylic acid compound selected from the group consisting of succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid and hexahydrophthalic acid, based on the weight of the polyamide fiber obtained. Added at a ratio of 5 to 4%, after melt spinning, 50 to 14%
A method for producing flame-retardant polyamide fibers by hot stretching at a temperature of 0°C. The polyamide used in the present invention means ordinary synthetic linear polyamides, such as nylon 6, nylon 10, nylon 11, nylon 12, nylon 66.
, nylon 610, and copolyamides containing these as main components, among which nylon 6 and nylon 66 are preferably used.

The nuclear halogenated aromatic compound used in the present invention is represented by the general formula (1). Examples of such nuclear halogenated aromatic compounds include tribromobenzene, tribromotoluene, tetrabromobenzene, pentabromobenzene, pentabromoethylbenzene, pentabromotoluene, hexabromobenzene, pentabromo-n-decylbenzene, trichlorotoluene, and tetrabromobenzene. Chlorbenzene,
Nuclear halogenated benzene derivatives such as pentachlorobenzene, pentachlorotoluene, hexachlorobenzene, pentachloroethylbenzene, tetrachloroethylbenzene, tetraprom diphenyl ether, pentaprom diphenyl ether, hexaprom diphenyl ether,
Nuclear halogenated diphenyl ether derivatives such as decaprom diphenyl ether, triprom dichloro diphenyl ether, decachlor diphenyl ether, pentaprom pentachlor diphenyl ether, pentaprom diphenyl, hexachlor diphenyl, hexaprom diphenyl enyl, decapromdiphenyl, decachlordiphenyl, 4
- Nuclear halogenated diphenyl derivatives such as methyl nonaprom diphenyl and 4-n-decyl nonaprom diphenyl, nuclear halogenation such as pentaprom diphenylmethane, decaprom diphenylmethane, decabrom-1,10-diphenyldecane, etc. Diphenylalkyl derivative, benzyloxypentachlorobenzene, 1,2-di(2',4',
6'-tripromephenoxy)ethane, 1,6-di(2
Examples include ',4',6'-tripromephenoxy)hexane. Among these, nuclear bromine compounds are preferred from the viewpoint of imparting flame retardant properties, and in particular hexabromobenzene, pentabromotoluene, pentapromoethylbenzene, pentapromobenzene, tetrabromobenzene, tribromotoluene, diphenyl ether bromide ( 4 to 10), biphenyl bromide (bromine number 4 to 10), biphenyl bromide (bromine number 4 to 10),
~10) are preferred. On the other hand, the carboxylic acid compounds used in the present invention include the above-mentioned succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid,
Examples include hexahydrophthalic acid, among which succinic acid and hexahydrophthalic acid are preferred.

The amounts of both of the above compounds added can be appropriately selected depending on the intended use of the polyamide fiber.

Generally, the flame retardant performance increases as the amount added increases, but it must be added within a range that does not adversely affect the operability during spinning and drawing and the quality of textile products. Nuclear halogenated aromatic compounds are 0
．． 5 to 15% by weight, and the carboxylic acid compound is 0.5 to 15% by weight.
It may be used within a range of 4% by weight. Even if the amount of carboxylic acid compound added is within the range of 0.5 to 4% by weight, if the amount of nuclear halogenated aromatic compound is less than 0.5% by weight, the flame retardant performance of the fiber is not sufficient, and conversely, the flame retardant performance of the fiber is insufficient. If the amount is more than % by weight, it is not preferable because spinnability and drawability are reduced, the color tone of the product yarn is deteriorated, and a large amount of halogen gas is generated when the product yarn is burned. In addition, the nuclear halogenated aromatic compound is 0.5
Even within the range of ~15% by weight, the carboxylic acid compound is 0.
．． If it is less than 5% by weight, flame retardant properties etc. will not be sufficiently imparted, and if it is more than 4% by weight, spinnability and stretchability will deteriorate, which is not preferable. From this point of view, a more preferable range is 1 to 7% by weight of the nuclear halogenated aromatic compound and 0.7 to 2% by weight of the carboxylic acid compound, and particularly preferably 1 to 4% by weight of the nuclear halogenated aromatic compound. . In the method of the present invention, the above-mentioned nuclear halogenated aromatic compound and carboxylic acid compound are added to polyamide and melt-spun.

The timing of addition is preferably after the polyamide is turned into chips.
If added before, during or at the end of polymerization, undesirable phenomena such as coloring of the polyamide may occur. The method of adding both of the above compounds to the polyamide is not particularly limited.

For example, a specified polyamide and both compounds are put into a rotating drum and mixed, or the mixture obtained by mixing the polyamide and both compounds in a mixer is melt-kneaded using a known extruder or grid-type melting device, and then spun. I can do that. It is also possible to prepare a master chip by mixing and melting both of these compounds in polyamide at a high concentration, and then mixing and diluting ordinary polyamide chips to a predetermined concentration and spinning. In either method, it is necessary to mix until the mixture is sufficiently uniform.

If the mixing is insufficient, troubles such as yarn breakage may occur during the melt spinning process, and the quality of the resulting polyamide fibers will be less uniform. Therefore, a total of 5 minutes or more is required for mixing the polyamide and both compounds in a molten state, including the melt spinning step. However, if the mixing time is too long, changes in the physical properties of the polyamide will increase to a non-negligible extent, so the melt mixing time should be at most 1 hour. As the melt spinning method, a conventionally known melt spinning method can be adopted.

That is, for example, there is a method in which the nuclear halogenated aromatic compound and the carboxylic acid compound are mixed with polyamide chips, melted in an extruder, metered with a gear pump, extruded from a spinneret, and then formed into a thread and wound up. At this time, it is also possible to melt the polyamide, knead it in a kneading device such as a static mixer (for example, 1SG mixer manufactured by Tokushu Kaika Kogyo Co., Ltd.), and then spin it. The spinning temperature can be arbitrarily selected depending on the polyamide used and the type and amount of both compounds added, but generally the spinning temperature is higher than the melting point of the polyamide.
A range of 80°C or less is desirable. Preferably, the range is the melting point of polyamide + (10 to 50°C). After melt spinning by the above method, the obtained undrawn polyamide yarn is drawn at a draw ratio of 11 or more, preferably 30 or more.

When drawing, a method of hot drawing at a temperature in the range of 50° C. to 140° C. is convenient for preventing drawn yarn breakage and stabilizing quality. Examples of hot stretching methods include hot pin stretching and hot roller stretching, but hot pin stretching is particularly preferred. According to the method of the present invention, flame-retardant polyamide fibers having excellent flame retardancy and without degrading the original excellent properties of polyamide can be obtained very easily. In the present invention, by using the above-mentioned carboxylic acid compound in combination, the amount of the nuclear halogenated aromatic compound to be blended can be much smaller than in the past, which is advantageous in terms of cost.
In addition, there were no problems with spinnability, and the light resistance of the resulting fibers was
The whiteness etc. are also sufficiently satisfactory. Furthermore, it is also possible to greatly reduce the generation of toxic halogen gases during combustion of the polyamide fibers. In the method of the present invention, there is no problem in adding third components to the polyamide, such as matting agents, antioxidants, heat stabilizers, light stabilizers, antistatic agents, colorants, and fluorescent brighteners. The present invention will be explained in detail below with reference to Examples.

In the Examples, the relative viscosity [ηRel] is the value measured by an Ostwald viscometer at 25° C. after dissolving the polyamide in concentrated sulfuric acid to a concentration of 1%. Flame retardancy is evaluated using the limiting oxygen index (L, O, I) according to the following measurement method.
) and the number of times of flame contact using the 45° coil method. J(a) L, O, I measurement method Fabric sample is JIS-K-7201-1972A method-2
L, O, and I were measured according to No.

For yarn samples, weigh 0.5 g from the fiber to be tested;
A twisted rod with a length of 100 mm and a twist number of 10 was prepared, a wire was inserted into the center, and the rod was held vertically at the center bottom of a combustion cylinder and measurements were made in the same manner. (b) Method for measuring the number of times of flame contact using the 45° coil method The cloth sample is based on JIS-L-1091-19.
The number of flame contacts was measured according to the 71D method.

For yarn samples, a twisted rod with a weight of 1 g, a length of 100 mm, and a number of twists of 10 is made from the fiber to be tested, and this twisted rod is
．． Insert it into a coil made of 5mmφ stainless steel wire with a diameter of 10mm, a coil pitch of 2mm, and a length of 150mm, hold it at a 45 degree angle, and burn it by touching the lower end with a Mitaro burner with a flame length of 45mm for 10 seconds. When the flame goes out, shift the position and apply the flame again to the lower end in the same way. In this way, the number of times of flame contact until 10 cm of the twisted rod was completely burnt out was measured, and the average value of the five times was shown. The compatibility test method and evaluation method are as follows. That is, 30mmφ×200m
About 27 g of polyamide brite pellets and a predetermined amount of the compound are thoroughly mixed and then poured into a test tube.

To prevent oxidation of the polyamide, the test tube is heated to a temperature higher than the melting point of the polyamide while flowing nitrogen to melt the contents. After melting, mix thoroughly and uniformly with a stirring rod. Next, the state of the melt was observed with the naked eye through the glass wall, and the evaluation was roughly divided into the following three stages. ◯=uniformly dissolved, the polymer was transparent, and no oil droplet dispersion was present.

Δ=Most of the polymer is dissolved, but the polymer is translucent due to some dispersion.

× = Polymer is opaque, and a large amount of undissolved matter is dispersed.

However, in the case of being located in the middle of the above three stages, an intermediate display such as 〇△ was used.

The evaluation criteria for colorability are as follows.

That is, the colored state of the fibers was visually evaluated as follows.
◎ = All < No coloration, equivalent to unmodified polyamide. ○=Slightly colored, but close to unmodified polyamide. Δ=Coloring is clearly observed compared to unmodified polyamide.

×1: Significant coloring compared to unmodified polyamide.

However, if the item is at an intermediate stage, an intermediate symbol such as △× is used. Moreover, evaluation of spinnability was performed as follows.

〇 = As few thread breakages as unmodified nylon 6, less than 1 thread breakage per 1 million m.

△ = Thread breaks approximately 5 to 20 times per million meters.

× = Yarn breakage occurs frequently and a satisfactory spun yarn cannot be obtained. However, when the yarn is at an intermediate stage, an intermediate indication such as △× is also used.

Example l Nylon 6 full-dull chip (relative viscosity 260, moisture content 0
．． The various compounds listed in Table 1 were thoroughly mixed in advance with 08% by weight) and melt-spun using a conventional extruder-type spinning machine at a temperature of 260° C. and a spinning speed of 600 m/min.

Next, the fiber was hot-stretched (hot-pin-stretched) to 3.4 times at a temperature of 90°C to obtain a 40-denier fiber consisting of 10 filaments. The combustibility of the obtained fibers was tested by measuring L, O, and I, and by measuring the number of flame contacts using a 45° coil method. The evaluation methods for compatibility, colorability, spinnability, etc. are as described above.

The results are shown in Table 1.

As shown in Table 1, nuclear halogenated aromatic compounds 4.0
% by weight and 1.5% by weight of a carboxylic acid compound into nylon 6 chips and spun the products C1 to 5) of the present invention, with almost no problems in compatibility, colorability, and spinnability. , its flame retardant performance is also excellent.

On the other hand, 6, f). 7 and 8 are cases where only 4% by weight of the nuclear halogenated aromatic compound was blended and spun, and although there were no problems with compatibility, colorability, spinnability, etc., the important flame retardant No performance improvement effect was observed. Also f).
No. 9 and No. 10 are cases in which 4% by weight of a nuclear halogenated aromatic compound and 2% by weight of antimony trioxide are combined, but these have poor compatibility and spinnability, and their flame retardant effect is still insufficient. In case No. 11, the amount of pentabromotoluene was increased from that in case No. 7, and it was blended and spun to 10% by weight. Although the flame retardant performance was improved due to the increased additive amount compared to Black 7, it was still not sufficient, and the colorability and spinnability deteriorated. Example 2 Nylon 6 full dual tip (relative viscosity 255, moisture content 0)
．． 09% by weight), succinic acid and hexabromidiphenyl ether in various proportions were thoroughly mixed in advance, and a 40-denier fiber consisting of 10 filaments was obtained in the same manner as in Example 1.

The L. O. I. The number of flame contacts was measured using the 45° coil method. Compatibility, colorability, and spinnability were also evaluated using the methods described above. The results are shown in Table 2. As is clear from the results in Table 2, when succinic acid or hexaprom diphenyl ether was added alone, almost no flame retardant performance improvement effect was observed, but when both were used together in appropriate amounts, It was possible to obtain nylon 6 fibers having excellent flame retardant performance without degrading the original properties of nylon 6.

Example 3 Nylon 66 chips (relative viscosity 245) were thoroughly mixed with the various compounds listed in Table 3, and the same method as Example 1 was used except that the spinning temperature was 270°C and a 40 denier film consisting of 10 filaments was prepared. Obtained fiber.

The L. O. I. The number of flame contacts was measured using the 45° coil method. Compatibility, colorability, and spinnability were also evaluated using the methods described above. The results are shown in Table 3. As is clear from the results in Table 3, the products of the present invention (Haruka 1 to 3), which use a combination of a nuclear halogenated aromatic compound and a carboxylic acid compound, have excellent flame retardant performance and other good properties. However, when the nuclear halogenated aromatic compound was used alone (▲4 to 6), the flame retardant performance did not improve, and when the amount added was increased ('9), it had an adverse effect on the polyamide properties.

Furthermore, even if antimony trioxide, a known flame retardant aid, is used in combination (7-8), the flame retardant performance is insufficient, and the compatibility is poor.
Properties such as spinnability also deteriorated. Example 4 Nylon 6 semi-double chips (relative viscosity 2.60, moisture content 0.08% by weight) were thoroughly mixed with 1.3% by weight of succinic acid and 3.5% by weight of decapromobiphenyl in a conventional extruder type 1. Using a spinning machine at a temperature of 260°C and a spinning speed of 6
Melt spinning was performed at 00 m/min.

The obtained undrawn yarn was drawn by various drawing methods as shown in Table 4. However, the stretching ratio is 3.4 in all cases. Table 4 shows the measurement results of stretchability and yarn unevenness (R%) of the drawn yarn. As shown in Table 4, in cold drawing, the drawability is insufficient regardless of the presence or absence of pins, and the R% value is also high and is still insufficient even with pins.

A high R% value means that the thickness of the yarn is non-uniform, which is not preferable because it is expected that there will be some undrawn parts, which is likely to cause problems such as dyeing spots. In hot stretching, the hot pin stretchability and hot roller single stretching are both good in stretchability and R% value.

However, when the stretching temperature is 40° C., the R% value tends to increase and the stretchability also decreases to some extent, which is not preferable. On the other hand, when the stretching temperature is 150° C., although the R% value is good, the drawability is somewhat lowered, and in particular, the threads tend to fuse and breakage occurs frequently at the start of drawing, which is not preferable.

Therefore, the hot stretching temperature is preferably 50 to 140°C. Example 5 5% by weight of succinic acid and 12% by weight of pentapromethylbenzene were thoroughly mixed in advance with nylon 6 fulldulchip (relative viscosity 2.70, moisture content 0.08% by weight), and melted at 250°C using an Edust router. Kneaded and obtained master chips.

Such a master chip has a succinic acid content of 1.25% by weight and a pentapromethylbenzene content of 3% by weight.
Nylon 6 full dual tip (relative viscosity 2.
70, moisture content 0.08% by weight) and was mixed well using an extruder type spinning machine at a temperature of 255°C and a spinning speed of 650m.
/min. Next, the fiber was hot-stretched by about 3.3 times using a hot pin at 90° C. to obtain a 40-denier fiber consisting of 1.0 filament. The strength of this fiber was 48 g/d and the elongation was 35%, which was not much different from that of unmodified nylon 6 ordinary yarn.
This fiber was subjected to normal warping and knitting to obtain a tricot sample. There were no particular problems with workability during warping and knitting, and the results were comparable to those of unmodified nylon 6. Further, this tricot sample was subjected to usual scouring and dyeing. Dyeing was carried out by both dispersion dyeing and acid dyeing, and the dyeability was good with no major difference from unmodified nylon 6. In order to evaluate the flame retardant performance of the obtained dyed tricot cloth, the number of times it was exposed to flame was measured.

Claims (1)

[Claims] 1 Polyamide has the general formula (1) ▲ Numerical formula, chemical formula, table, etc. ▼ ... (1) [In the formula, X is chlorine and/or bromine, Y is R, OR or OR'
OR (R is an alkyl group, aryl group, or nuclear halogenated aryl group having 1 to 10 carbon atoms, or an aralkyl group or halogenated aralkyl group having 7 to 16 carbon atoms, and the carrier halogen is chlorine and/or bromine; R' is (alkylene group having 1 to 6 carbon atoms), 1 is an integer of 2 to 6, and m is 0 or 1. ] 0.5 to 15 based on the weight of the polyamide fiber obtained from at least one type of nuclear halogenated aromatic compound
%, and at least one carboxylic acid compound selected from the group consisting of succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid and hexahydrophthalic acid.
．． Added at a ratio of 5 to 4%, after melt spinning, 50 to 140
A method for producing flame-retardant polyamide fibers by hot stretching at a temperature of ℃. 2. The manufacturing method according to claim 1, wherein the polyamide is nylon 6 or nylon 66. 3. The production method according to claim 1, wherein in the nuclear halogenated aromatic compound represented by general formula (1), all halogens are bromine. 4 The nuclear halogenated aromatic compound represented by the general formula (1) is hexabromobenzene, pentabromotoluene, pentabromoethylbenzene, pentabromobenzene, tribromotoluene, diphenyl ether bromide with a bromine addition number of 4 to 10, and a bromine addition number 4 The manufacturing method according to claim 3, which is at least one compound selected from the group consisting of -10 biphenyl bromides. 5 1 for the weight of the polyamide fiber from which the nuclear halogenated aromatic compound represented by the general formula (1) is obtained in the polyamide
The manufacturing method according to claim 1, 3, or 4, wherein ~7% is added. 6. The production method according to claim 1, wherein the carboxylic acid compound is succinic acid and/or hexahydrophthalic acid. 7. The manufacturing method according to claim 1 or 6, wherein the carboxylic acid compound is added to the polyamide in an amount of 0.7 to 2% based on the weight of the polyamide fiber obtained. 8. The manufacturing method according to claim 1, wherein a nuclear halogenated aromatic compound represented by general formula (1) and a carboxylic acid compound are added to the polyamide after chipping. 9. The manufacturing method according to claim 1, wherein the hot stretching is hot pin stretching or hot roller stretching. 10. The manufacturing method according to claim 9, wherein the hot stretching is hot pin stretching.