WO2006087983A1

WO2006087983A1 - Flame-retardant polyvinyl alcohol fiber

Info

Publication number: WO2006087983A1
Application number: PCT/JP2006/302434
Authority: WO
Inventors: Ryota Komiya; Ryokei Endo; Hideki Kamada; Shunichiro Watanabe
Original assignee: Kuraray Co., Ltd
Priority date: 2005-02-21
Filing date: 2006-02-13
Publication date: 2006-08-24
Also published as: JPWO2006087983A1

Abstract

A flame-retardant PVA fiber, which is excellent in mechanical characteristics such as strength and elastic modulus while exhibiting high flame retardance, is efficiently obtained at low cost. This flame-retardant PVA fiber is suppressed in shrinkage when it is burnt. Specifically disclosed is a flame-retardant PVA fiber which is composed of a PVA polymer having a polymerization degree of not less than 1200 and a saponification degree of not less than 90 mol%, a halogen-containing vinyl polymer and a layered silicate. This flame-retardant PVA fiber is characterized in that the average interlayer distance of the layered silicate is not less than 20 ú.

Description

Specification

Flame retardant polybula alcohol fiber

Technical field

[0001] The present invention mainly comprises a polybulal alcohol (hereinafter, sometimes referred to as PVA) -based polymer, a fluorine-containing polymer, a logene vinyl polymer (hereinafter sometimes referred to as PVX), and a layered silicate. The present invention relates to a flame retardant PVA fiber as a component.

Background art

Conventionally, as flame retardant fibers, acrylic fibers and polyester fibers copolymerized with flame retardant monomers, regenerated cellulose fibers kneaded and reacted with flame retardant agents, and polymers themselves are flame retardant. Thermosetting fiber jaramide fiber, cotton and wool post-processed with a flame retardant agent are widely known (see, for example, Patent Documents 1 and 2;). However, in the case of the acrylic fiber, cyan gas is generated during combustion, in the case of the polyester fiber, melt drip is generated, in the case of the thermosetting fiber, the fiber strength is low, and the aramid fiber. In this case, the fiber itself is very expensive, and in the case of cotton and wool, there are various problems such as texture hardening by post-processing.

[0003] On the other hand, flame retardant PVA fibers have not been melt drip, have high strength and have excellent washing durability, and thus have been attracting attention as various flame retardant fibers. It is known that the flame retardant PVA fiber combined with a halogen-containing polymer also exhibits a high degree of flame retardancy (see, for example, Patent Documents 3 and 4). However, these conventional flame retardant PVA fibers are still not sufficiently flame retardant, and even shrink when burned. It was. Therefore, flame retardant PVA fibers have been strongly demanded to further improve flame retardancy and suppress shrinkage during combustion.

[0004] In addition, in recent years, V, a so-called polymer nanocomposite technology that combines layered silicates with polymer materials at the nanometer level, has been actively studied, and this technology aims to improve polymer performance. Has been proposed. For example, a polyamide resin composition and filament containing a layered silicate, a filament composed of a reinforced polyamide containing a swellable fluoromica compound, and a swellable fluoromica compound were uniformly dispersed. Strengthen Artificial turf yarns composed of polyamide rosin have been proposed. In these, fiber dimensional stability, heat resistance, and heat resistance are achieved by uniformly dispersing the layered silicate in polyamide-based rosin. It is described that the aqueous property is improved (for example, see Patent Documents 5 to 7).

[0005] It has also been proposed to use a layered silicate as a flame retardant. For example, a flame retardant molded article made of polybulal alcohol resin containing a layered silicate has been proposed, and it is described that flame retardancy is improved (see Patent Document 8).

[0006] Furthermore, PVA fibers in which layered silicates are nano-dispersed are also known (see Patent Document 9), but according to the study by the present inventors, their flame retardancy is not practical. Far away, for example, the flame retardant performance was insufficient compared to the conventional flame retardant PVA fiber composited with a halogen-containing vinyl polymer.

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2003-335962

Patent Document 2: JP-A-1-221537

Patent Document 3: Japanese Patent Laid-Open No. 3-126749

Patent Document 4: JP-A-5-78909

Patent Document 5: Japanese Patent Laid-Open No. 3-81364

Patent Document 6: JP-A-8-3818

Patent Document 7: Japanese Patent Laid-Open No. 10-130956

Patent Document 8: Japanese Unexamined Patent Publication No. 2000-095915

Patent Document 9: Japanese Unexamined Patent Application Publication No. 2005-9029

Disclosure of the invention

Problems to be solved by the invention

[0008] An object of the present invention is to provide a flame retardant PVA fiber having improved flame retardance that does not impair mechanical properties such as strength and elastic modulus inherent in the PVA fiber, and shrinkage during combustion. And a method of manufacturing the same.

Means for solving the problem

[0009] As a result of intensive studies to obtain the above-mentioned flame-retardant PVA fibers, the present inventors have obtained a function by combining PVX polymers and layered silicates under specific conditions. It has been found that flame retardant PV A-based fibers having improved flame retardancy and shrinkage during combustion can be produced without degrading mechanical properties. That is, the present invention comprises a PVA polymer having a polymerization degree of 1200 or more and a saponification degree of 90 mol% or more, and PVX, a layered silicate, and the average interlayer distance of the layered silicate is 20 A or more. The flame retardant PVA fiber, preferably 15 to 65% by mass of PVX polymer and 1 to 30% by mass of layered silicate with respect to the PVA polymer. More preferably, it relates to a flame retardant PVA fiber in which the layered silicate is a smectite clay composite or a synthetic fluorine mica.

[0010] Further, the present invention provides the above flame-retardant PVA fiber characterized by spinning and drawing a spinning stock solution in which PVX and a layered silicate are uniformly dispersed in a solution in which PVA is dissolved. The present invention relates to a fiber manufacturing method.

The invention's effect

[0011] According to the present invention, an efficient and low-cost PVA-based flame retardant fiber having excellent mechanical properties such as strength and elastic modulus, high flame retardancy, and suppressed shrinkage during combustion. And can be applied to a wide variety of uses.

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] The present invention will be specifically described below. First, the PVA polymer constituting the PVA fiber of the present invention will be described. The degree of polymerization of the PVA polymer used in the present invention is not particularly limited, but taking into account the mechanical properties and dimensional stability of the resulting fiber, the average polymerization was also determined for the 30 ° C aqueous solution viscosity. The degree must be 1200 or more. A polymer having a high degree of polymerization is preferred because it is excellent in terms of strength, heat and humidity resistance, and the like, but a polymer having an average degree of polymerization of 1500 to 5000 is preferred from the viewpoint of polymer production cost and fiberization cost.

[0013] The degree of saponification of the PVA polymer to be used must be 90 mol% or more, and 98 mol% or more is preferred in view of the mechanical properties and water resistance of the resulting fiber. 99 mol% The above is more preferable. 99. More than 7 mol% is particularly preferred since it has excellent hot water resistance.

[0014] The PVA polymer constituting the fiber of the present invention is mainly composed of a bull alcohol unit. As long as it is a minute, it is not particularly limited, and other structural units may be included. Examples of such structural units include olefins such as ethylene, propylene, and butylene, acrylic acid and its salts and acrylic esters such as methyl acrylate, methacrylic acid and its salts, and methacrylic acid such as methyl methacrylate. Esters, acrylamide derivatives such as acrylamide and N-methyl acrylamide, methacrylamide derivatives such as methacrylamide and N-methylol methacrylamide, N-butamides such as N-Buylpyrrolidone, N-Buylformamide and N-Bulacetoamide , Aryl ethers having polyalkyleneoxide in the side chain, butyl ethers such as methyl beryl ether, nitriles such as acrylonitrile, halogenated burs such as butyl chloride, maleic acid and its salts or anhydrides thereof and the like ester Unsaturated dicarboxylic acids and the like. Such a modified unit may be introduced by copolymerization or post-reaction. Of course, as long as the effects of the present invention are not impaired, additives such as a dispersant, a stabilizer, a pH adjuster, and a special function agent may be included depending on the purpose.

[0015] The fiber of the present invention needs to contain PVX as the first constituent component other than the PVA polymer. PVX in the present invention is a bull polymer having 50% or more of units containing a halogen element, that is, fluorine, chlorine, bromine and iodine. Examples of PVX include salt vinyl polymer (PVC), salt vinylidene polymer, vinyl bromide polymer, vinyl bromide polymer, chlorinated polyolefin, brominated polyolefin, etc. Among these, PVC is also preferred for its flame retardancy, thermal decomposition resistance, and cost.

[0016] PVX contributes to the improvement of flame retardancy, so the greater the content, the better the flame retardancy. In order to impart the desired flame retardancy, it is preferred to contain 15% by mass or more with respect to the PVA polymer, more preferably 30% by mass or more. On the other hand, if the PVX content exceeds 65 mass%, the mechanical properties of the fiber tend to be insufficient, so the PVX content is more preferably 50 mass% or less. For the purpose of improving flame retardancy, additives other than PVX, that is, tin compounds such as magnesium hydroxide, aluminum hydroxide and stannic oxide, antimony compounds, phosphate compounds, iron oxides, etc. It is also possible to add a known flame retardant aid such as [0017] The fiber of the present invention needs to contain a layered silicate as a second constituent component other than the PVA polymer. As the layered silicate to be used, those having a layer charge force so. 2 to 2.0 and a cation exchange capacity such that the cation exchange amount is 50 to 200 meq / 100 g are preferable. Specifically, smectite clay compounds such as montmorillonite, sabonite, hydelite, nontronite, hectorite, bi-mouth site and stevensite, divermicilite, trivermycillite, fluorine vermiculite, etc. Vermiculite clay composites, muscovite, noragonite, illite and other mica clay composites, Li-type fluorine theolite, Na-type fluorine theolite, synthetic fluorine-mica (Li-type tetrasilicon Fluorine mica, Na-type tetrasilicon fluorine mica, and the like. These may be natural products or synthetic products. Furthermore, in the present invention, these layered silicates can be used alone or in combination of two or more. Among these, smectite clay composites or synthetic fluorinated mica are low in cost, and are particularly preferred from the viewpoint of fiberization processability, fiber flame retardancy, and suppression of combustion shrinkage.

[0018] As the content of the layered silicate is increased, the flame retardancy is improved, and further, the shrinkage during combustion can be suppressed. In order to obtain desired flame retardancy and combustion shrinkage suppression effects, it is preferable to contain 1% by mass or more based on the PVA polymer. However, if the content of the layered silicate exceeds 30% by mass, the mechanical properties of the fiber are likely to be impaired. Therefore, the content is preferably 1 to 30% by mass. % Is more preferable.

In the present invention, the shrinkage during combustion is evaluated by measuring the dry heat contraction rate (Dsr) by the method described in Examples described later.

In the fiber of the present invention, it is necessary that the layered silicate used is nano-dispersed uniformly in the fiber so that the average interlayer distance is 20 A or more. When the average interlayer distance is less than 20 A, the intercalation between the polymer layers is insufficient, the layered silicate is not nano-dispersed in the fiber, and the desired physical properties are not exhibited. Here, the interlayer distance refers to the distance between the center of gravity of the plate of the layered silicate, and is specifically determined from the peak position of the (001) plane reflection of the layered silicate detected by wide-angle X-ray diffraction. The average interlayer distance is a value obtained by the method described in the examples described later. Nanodispersion is a layer of layered silicate, Or, on average, a multi-layer force of 10 layers or less means a state of being dispersed finely without forming a local lump in parallel or randomly, or in a state where parallel and random are mixed. In the fiber of the present invention, as shown in FIG. 1, the existence form of the layered silicate can be confirmed only by a transmission electron microscope (TEM).

[0020] The improvement in flame retardancy, which is one of the effects of the present invention, is considered to be because the diffusion of the volatile gas generated by the combustion of the PVA polymer is blocked by the layered silicate. . In the fiber of the present invention, the PVA polymer is intercalated between the layers of the layered silicate to expand the layers, and the layered silicate is nano-dispersed. Large area that can block diffusion. On the other hand, if the dispersion of the layered silicate is insufficient, that is, if the average interlayer distance is less than 20A, the area cannot be increased, and the desired flame retardancy cannot be obtained.

PVX, which is the first component other than the PVA polymer described above, has a radical scavenging function, which is known to be a mechanism for improving flame retardancy. The flame-retardant PVA system of the present invention exhibits remarkable flame retardancy due to the synergistic effect of PVX and the nano-dispersed layered silicate with the combustion gas diffusion blocking effect.

[0021] The fineness of the fiber obtained by the present invention is not particularly limited. For example, fibers having a fineness of 0.1 to LOOOOdtex, preferably 1 to LOOOdtex can be widely used. The fineness of the fiber should be adjusted appropriately according to the nozzle diameter and draw ratio.

[0022] Next, a method for producing the fiber obtained by the present invention will be described.

The flame-retardant PVA fiber of the present invention is produced by wet spinning, dry-wet spinning, or dry spinning of a spinning stock solution containing a PVA polymer, PVX, and a layered silicate. Solvents used in the spinning dope include those conventionally used in the production of PVA fibers, such as water, dimethyl sulfoxide (DMSO), dimethylformamide, dimethylacetamide, or glycerin, ethylene glycol, triethylene glycol, etc. One or a combination of two or more of polyhydric alcohols, diethylenetriamine, and rhodan salts can be used. Among these, water and DMSO are particularly preferable from the viewpoint of supplyability and impact on the environmental load. The method for preparing the stock solution is not particularly limited. PVA polymer, PVX, and layered silicate are each dissolved or dispersed in the stock solution solvent alone. Either a method of mixing the ingredients in an appropriate ratio, or a method of dissolving and dispersing them in batches in the undiluted solvent can be employed. There is no particular limitation on the order of addition.

. The concentration of solid content in the spinning dope (total amount of PVA polymer, PVX and layered silicate) is generally in the range of 6 to 60% by mass depending on the composition and degree of polymerization of the PVA polymer and the solvent. The liquid temperature at the time of discharging the spinning dope is preferably within a range where the spinning dope is not decomposed or colored, and is specifically preferably 50 to 150 ° C. Wet spinning is a method in which the spinning solution is discharged directly into the solidification bath, while dry and wet spinning is in the air or in an inert gas at an arbitrary distance from the spinning nozzle. The spinning solution is discharged and then introduced into the solidification bath.The dry spinning is the spinning nozzle force. The spinning solution is discharged into the air or inert gas without passing through the solidification bath. It is a method of obtaining fibers by drying.

[0023] Next, the thread formed in the solidification bath may be subjected to a wet stretching process, a drying process, a dry heat stretching process, and the like. In order to suppress interfiber sticking and improve the mechanical performance of the fiber, the wet draw ratio is preferably 1.5 to 5 times. Furthermore, it is preferable to improve the mechanical performance through a dry heat drawing step. As for the point force to obtain sufficient mechanical performance, it is preferable to set the total draw ratio to 6 times or more, and the dry heat drawing temperature is preferably about 200 to 250 ° C. In the present invention, the total stretch ratio is a ratio represented by the product of the wet stretch ratio and the dry heat stretch ratio. In order to increase water resistance, heat treatment is performed, and monoaldehydes such as formaldehyde, dartaldehyde, nonane dialdehyde, or derivatives thereof are used to acetalize the PVA molecule and Z or between molecules. However, it may be crosslinked with other crosslinking agents.

[0024] As described above, in the present invention, the layered silicate must be nano-dispersed in the PVA polymer. As a means for achieving this, for example, a PVA spinning stock solution prepared in advance and a layered silicate dispersion can be prepared and mixed to give a sufficient shearing force. Here, in order to give a sufficient shearing force, it is preferable to give high-speed stirring or lengthen the stirring time. In addition, when shear is applied in a relatively low-viscosity solution state, the PVA-based polymer is interlaced with the layered silicate and the nano-dispersion of the layered silicate tends to proceed. Specifically, PVA poly Solution viscosity at 90 ° C of a mixed solution of mer and layered silicate When rotated at 6 rpm using a B-type viscometer, it is preferred to be less than 700 boise. Is preferable. If it exceeds 700 boise, the stirring efficiency will deteriorate and it will be difficult to apply uniform shear stress to the entire solution.

[0025] The fiber of the present invention can be used in any fiber form such as a stable fiber, a shortcut fiber, a filament yarn, and a spun yarn. The cross-sectional shape of the fiber at that time is not particularly limited even if it is a circular, hollow, or atypical cross section such as a star. Sarako may mix and use the fibers of the present invention with other fibers. At this time, the fibers that can be used in combination are not particularly limited, and examples thereof include PVA fibers that do not contain a layered clay compound, polyester fibers, polyamide fibers, and cellulose fibers.

[0026] Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the examples. In Examples, fiber strength, dry heat shrinkage, limiting oxygen index (LOI value), and average interlayer distance of the layered silicate are obtained by the following measurement methods.

[0027] [Fiber strength cNZdtex]

In accordance with JIS L1013, a pre-humidified yarn was measured under the conditions of a test length of 20 cm, an initial load of 0.25 cN / dtex and a tensile strength of 50% Z, and an average value of n = 5 was adopted. The fiber fineness (dtex) was determined by the mass method.

[0028] [Dry heat shrinkage (Dsr)%]

In accordance with JIS L1013, a yarn with a test length of lm was kept in a dryer at 300 ° C for 1 minute, and the shrinkage rate was measured when a load of lZlOg per yarn fineness was applied. By measuring this Dsr, the shrinkage during combustion was evaluated.

[0029] [Limited oxygen index value (LOI value)]

In accordance with JIS K7201, when making a 18 cm long sample with a braided fiber and igniting the upper end of the sample, the sample burns continuously for more than 3 minutes, or after ignition The minimum oxygen concentration required to continue burning over 5 cm in length was measured, and an average value of n = 3 was adopted.

[0030] [Average interlayer distance A of layered silicate] The average interlaminar distance of the layered silicate dispersed in the fiber was measured using CuK α-rays monochromatized with a graph-eye monochromator with a wide-angle X-ray diffractometer (“RINT2400” manufactured by Rigaku Corporation) Measurement was performed under the condition of 40 mV to 100 mA. Measures the angular dependence of diffraction intensity in the direction perpendicular to the fiber axis under the conditions of a scan speed of 2 Θ = 1 ° / min, a step width of 0.01 °, and a scan angle of 2 ° ≤ 2 Θ ≤ 10 °. did. The diffraction peak position from the (001) plane of the layered silicate was taken as the average interlayer distance, and calculated from the following Bragg equation.

[0031] [Equation 1] ά = λ / 2 s i n e

here

λ: X-ray wavelength (1.5 1 4 2 Α)

Θ: diffraction angle

[0032] [Example 1]

(1) PVA with an average degree of polymerization of 1700 and a key degree of 98.2 mol% was dissolved in water to a concentration of 20% by mass, and then PVC-water emulsion (40% concentration) with a degree of polymerization of 1000 was Mixing was performed so that the PVC content was 60% by mass with respect to PVA. Further, 1% by mass of boric acid and acetic acid was mixed to prepare a solution (Α). On the other hand, 95.5 parts by weight of water and montmorillonite (ΜΜΤ, Kunimine Kogyo Co., Ltd. “Kunipia F”) 4.5 parts by weight of the mixture were used in a high speed mixer (Osaka Chemical Co., Ltd. Oster Blender) Then, high-speed stirring (13 lOOrpm) for 30 minutes was performed to prepare a dispersion liquid (B) in which MMT was nano-dispersed. Further, mix solution (A) and dispersion (B) so that the amount of MMT added is 12% by mass with respect to PVA, and stir at 90 ° C for 5 hours at the same high speed mixer as above. A spinning dope was obtained by (13 lOOrpm). The solution viscosity of the spinning dope at this time was 50 poise when rotated at 6 rpm using a B-type viscometer.

(2) This spinning dope was extruded through a die with a pore size of 0.08 mm and a pore number of 1000 into a 40 ° C coagulation bath containing 20 g ZL sodium hydroxide and 350 g ZL sodium sulfate to form a thread. After treatment with lOOgZL sulfuric acid and 300gZL sodium sulfate temperature 35 ° C After neutralization through a bath, washing with water and drying, a fiber subjected to 5 times wet drawing was obtained. Thereafter, the fiber was stretched twice in a hot air oven at 230 ° C to obtain a fiber having a stretch ratio of 10 times.

(3) The average interlayer distance of the layered silicate over the obtained fiber was 28 A for the fiber subjected to 5 times wet drawing, 27 A for the fiber having a draw ratio of 10 times, and in the fiber The dispersion state of the layered silicate was nano-dispersed as shown in FIG. Further, the limited oxygen index value (LOI value), dry heat shrinkage (Dsr), and mechanical properties of the obtained fiber were evaluated. Table 1 shows the results of fiber performance evaluation. As shown in Table 1, the fibers obtained by the above method were excellent in both flame retardancy and combustion shrinkage in addition to the mechanical properties of conventional PVA fibers.

[0033] [Example 2]

Fibers were obtained by spinning under the same conditions as in Example 1 except that the amount of MMT added was 16% by mass with respect to PVA. The fiber performance evaluation results are shown in Table 1. The average interlaminar distance of the layered silicate in the obtained fiber is 25A for both the fiber that has been wet-stretched 5 times and the fiber that has been stretched 10 times, and the dispersion state of the layered silicate in the fiber is shown in the figure. As shown in Fig. 1, it was nano-dispersed. In addition to the mechanical properties of conventional PVA fibers, the obtained fibers were excellent in both flame retardancy and combustion shrinkage.

[0034] [Example 3]

Fibers were obtained by spinning under the same conditions as in Example 1 except that the amount of MMT added was 8% by mass with respect to PVA. The fiber performance evaluation results are shown in Table 1. The average interlaminar distance of the layered silicate in the obtained fiber is 28A for the fiber subjected to 5 times wet drawing and 29A for the fiber with a draw ratio of 10 times, and the dispersion state of the layered silicate in the fiber. As shown in Fig. 1, it was nano-dispersed. In addition to the mechanical properties of conventional PVA fibers, the resulting fibers were excellent in both flame retardancy and combustion shrinkage.

[0035] [Example 4]

The amount of added PVC was 30% by mass with respect to PVA, and fibers were obtained by spinning under the same conditions as in Example 1. The fiber performance evaluation results are shown in Table 1. In the obtained fiber, the average interlayer distance of the layered silicate is 28A for both the fiber subjected to 5 times wet stretching and the fiber having a stretching ratio of 10 times, and the dispersion state of the layered silicate in the fiber is shown in FIG. As shown in 1 Nano-dispersed. Furthermore, in addition to the mechanical properties of conventional PVA fibers, the obtained fibers were excellent in both flame retardancy and combustion shrinkage.

[0036] [Comparative Example 1]

Spinning was carried out under the same conditions as in Example 1 without adding the MMT dispersion and PVC emulsion to obtain a fiber of polybulal alcohol alone. The obtained fiber had a low LOI value, no flame retardancy, and dry heat shrinkage was extremely severe.

[0037] [Comparative Example 2]

A fiber containing only PVC as a component other than polyvinyl alcohol was obtained by spinning under the same conditions as in Example 1 except that no MMT dispersion was added. The obtained fiber had a low L OI value, inferior flame retardancy, and extremely severe dry heat shrinkage.

[0038] [Comparative Example 3]

A fiber having only MMT was obtained by spinning in the same manner as in Example 1 except that PVC was not added. The average interlaminar distance of the layered silicate in the obtained fiber was 29A for the fiber that was wet-stretched 5 times, and 28A for the fiber that was stretched 10 times. As a result, the obtained fiber had a low LOI value and inferior flame retardancy, and the flame retardancy was not at a practical level.

[0039] [Comparative Example 4]

In Example 1 (1), fibers were obtained in the same manner as in Example 1 except that the stirring time after mixing the solution (A) and the dispersion (B) was 1 hour. The resulting fiber had a short stirring time when the spinning solution was prepared, so the MMT average interlayer distance was 12 A, which was less than 20 A. As a result, the fiber was inferior in drawability, and the fiber with a draw ratio of 10 times was unable to obtain severe breakage. Furthermore, the obtained fiber was inferior in mechanical properties and flame retardancy (LOI value), and did not exhibit the effect of suppressing combustion shrinkage.

[0040] [Table 1] Amount added Average interlayer Fiber properties

(% By mass / PVA) Stretch ratio Distance LO I Ds r

PVC MMT (times) (A) (%)

Example 1 60 12 5 28 2. 2 33. 7 18

10 27 2. 4 34. 3 41

Example 2 60 16 5 25 1. 9 34. 4 10

10 25 3. 9 34. 8 25

Example 3 60 8 5 28 2. 3 33. 3 28

10 29 4. 5 33. 6 49

Example 4 30 12 5 28 2. 8 32. 5 19

10 28 5. 8 32. 5 43

Comparative Example 1 0 0 5 4. 3 18. 8 63

10 ― 9. 0 18. 5 76

Comparative Example 2 60 0 5 ― 2. 7 26. 8 61

10 ― 4. 6 27. 0 75

Comparative Example 3 0 12 5 29 4. 1 22. 8 20

10 28 8. 9 23. 0 47

Comparative Example 4 60 12 5 1 0. 5 29. 7 40

10 Cannot measure due to broken yarn

[0041] As is apparent from the results in Table 1, the flame-retardant PVA fiber of the present invention comprising the layered silicate having an average interlayer distance of 20A or more described in Examples 1 to 4 and PVX, Excellent flame retardancy such as LOI value and combustion shrinkage. On the other hand, it can be seen that PVA fibers do not contain PVX or layered silicate as in Comparative Example 1 and have no flame retardancy. In addition, as in Comparative Example 2, when only PVX is used as a flame retardant component, the combustion shrinkage is inferior. On the other hand, as in Comparative Example 3, sufficient flame retardant performance is not exhibited only with a layered silicate. I understand.

From these contrasts, the flame-retardant PVA fibers of Examples 1 to 4 that satisfy the constituent requirements of the present invention achieve the flame retardancy and suppression of combustion shrinkage more than expected in the comparative example, which is a conventional technique. I can tell you.

Furthermore, Comparative Example 4 in which the average interlayer distance of the layered silicate does not satisfy the requirements of the present invention indicates that sufficient characteristics are not exhibited in terms of mechanical properties, flame retardancy, and combustion shrinkage suppression. Industrial applicability

[0042] According to the present invention, a flame-retardant PVA fiber having excellent mechanical properties such as strength and elastic modulus, high !, flame retardancy, and suppression of shrinkage during combustion is efficiently and efficiently produced. It can be provided at low cost, and can be applied to a wide variety of uses that require high flame resistance, such as flameproof clothing. Brief Description of Drawings

[0043] [Fig. 1] Nano-dispersed layered silicate in the flame-retardant PVA fiber of the present invention FIG.

Claims

The scope of the claims

[1] Polybulal alcohol polymers with a polymerization degree of 1200 or more and a saponification degree of 90 mol% or more, and halogen-containing bull polymers, layered silicate strength, and the average layer distance of the layered silicate is 20A or more. A flame-retardant polybula alcohol fiber characterized by being.

[2] 15 to 65 mass of halogen-containing bully polymer with respect to polybulal alcohol polymer

2. The flame-retardant polyvinyl alcohol fiber according to claim 1, which comprises:

[3] The flame-retardant polybulal alcohol fiber according to claim 1 or 2, wherein the layered silicate is a smectite clay composite or a synthetic fluorine mica.

[4] The spinning stock solution in which the halogen-containing polymer and the layered silicate are uniformly dispersed in the polybulualcohol-based polymer solution is spun and drawn to produce a yarn. The manufacturing method of the flame-retardant polybula alcohol fiber as described in a term.