JPS60215812A - Polyimide fiber and its manufacturing method - Google Patents

Abstract

PURPOSE:To obtain the titled fibers having a high level of strength and elasticity and further improved moisture and light resistance, by melt spinning a copolyimide having repeating units derived from a specific aromatic diamine component and aromatic tetracarboxylic acid component. CONSTITUTION:A copolyimide, having repeating units derived from (A) an aromatic diamine component constituted of a mol component of formula I and if necessary b mol component of formula II and (B) an aromatic tetracarboxylic acid component constituted of c mol component of formula III and if necessary d mol component of formula IV in amounts satisfying the formula a+b= c+d at 0-1 ratio (b/a) and 0-3/7 ratio (d/c) and >=1.5 logarithmic viscosity number (inherent viscosity) is dissolved in a phenolic solvent to prepare a dope, which is then extruded into air, molded into a filament shape and coagulated in a coagulation bath. The resultant filaments are wound, washed, dried and hot-drawn at 250-420 deg.C at >=2 draw ratio to give the aimed fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a novel aromatic polyimide fiber and a method for producing the same.

[Prior art]

Aromatic polyimide is a polymer compound consisting of repeating units derived from an aromatic diamine component and repeating units derived from an aromatic tetracarboxylic acid component equivalent to the repeating unit, and has excellent heat resistance. Therefore, it is already widely used in films, varnishes, etc. In addition, attempts have been made to make aromatic polyimide into fibers, and these are as follows (1) and (
It can be roughly divided into two methods: 2).

(1) A method in which a polyamide and phosphoric acid solution is prepared by reacting a tetracarboxylic acid anhydride and a diamine, which is wet-spun into fibers, and then converted into polyimide fibers by heating.

(2) A method of synthesizing solvent-soluble polyimide and wet-spinning it to obtain polyimide fibers.

Method (1) is disclosed in, for example, Japanese Patent Publication No. 42-2936,
It is disclosed in Japanese Patent Publication No. 57-37687. However, this method requires careful control because water is generated when imidizing polyamic acid fibers.
In addition, pores are likely to be formed in the fibers due to the generation of water, making it impossible to produce high-strength fibers. Specifically, the special public
In the method disclosed in Japanese Patent No. 2936, the strength of the obtained fibers is only 2.8 to 6.6 fI/d, and the initial modulus of elasticity is as low as 31 to 77 f/d. In contrast, although improvements were made in the method disclosed in Japanese Patent Publication No. 57-37687, the fiber strength was still insufficient, with most of the fibers having a strength of about 10 Vd.

On the other hand, method (2), for example,
Although it is disclosed in Japanese Patent No. 33, the strength of the obtained fiber is only 1.27 to 2.65 Vd, and the initial elastic modulus is 32 to 2.65 Vd.
70 Vd, and satisfactory characteristics were not obtained.

In general, it is difficult to make fibers with sufficient strength and elastic modulus when using soft molecules that are easily soluble in solvents, and rigid polymers are difficult to dissolve in solvents and are difficult to form into fibers. .

Kevlar (trade name) manufactured by DuPont is a high-strength, high-elasticity polyamide fiber.
This fiber cannot exhibit sufficient properties in terms of moisture resistance and light resistance.

[Purpose of the invention]

The first object of the present invention is to have a high level of strength and elastic modulus that could not be achieved with conventional polyimide fibers, and
It is an object of the present invention to provide a polyimide fiber having excellent moisture resistance and light resistance.

A second object of the present invention is to provide a method for producing polyimide fibers that can stably and reproducibly produce polyimide fibers endowed with such excellent properties.

The first object of the present invention is to provide a polyimide fiber having repeating units derived from an aromatic diamine component and an aromatic tetracarpinic acid component, wherein the aromatic diamine component is a component of the following formula (A). a mol and optionally formula (B
), the aromatic tetracarpinic acid component is composed of C moles of the component of the following formula (C) and optionally d moles of the component of the formula (2), and a + b = e + d, A polyimide fiber characterized in that b/a is in the range of 0 to 1 and d/a is in the range of 0 to 3/7 (however, b and d are never 0 at the same time). achieved.

A second object of the present invention is to provide a copolyimide having repeating units derived from an aromatic diamine component and an aromatic tetracarboxylic acid component, wherein the aromatic diamine component is , consisting of a mole of component of the following formula (A) and optionally b mole of component of formula (B), and the aromatic tetracarzene acid component is composed of mole of component C of the following formula (M) and, as necessary, of the formula consisting of d moles of component (D), and a+b=a+d
holds true, b/a is in the range θ ~ 1, d/c is 0 ~ 3/
7 (however, b and d are never 0 at the same time) and has a logarithmic viscosity of 1.5 or more, is dissolved in a phenolic solvent to prepare a dope, and this dope is passed through a nozzle. After the filament is discharged into the air and formed into a filament, the filament is formed into a filament that is compatible with the phenolic solvent and is made of a filament. Production of polyimide fibers characterized by introducing the fibers into a coagulation bath in which polyimide is not soluble, coagulating the fibers, winding them up, washing and drying them, and then hot-drawing them at 250 to 420°C to double or more. This is achieved by law.

c/) O- [Embodiment] As mentioned above, the polyimide fiber m of the present invention
3,4′-diaminodiphenyl ether r(
An aromatic diamine component to which 9-rough ethylenediamine of the formula (B) is added as necessary, and 3.3 of the formula (C)
', 4,4'-Diphenyltetracaldic acid anhydride optionally added with pyromelliudic acid hydrothermal hydrate of the formula (b) above to form an aromatic tetracal repeating unit derived from phosphoric acid cape hydrate. f) , a' + b = c
The condition +d is a necessary condition for producing a high molecular weight polyimide.

Among the blending ratios of the above-mentioned (A) to the first component, the most preferable blending ratios are the following three cases (:) to 011).

(1) d=o, that is, a+b=c, and b/a
= 1/9 to 1, 0i) b=0, i.e. ame+d, and d/e
= 1/4 to 3/7, 10 b/a = 1/9
~3/7, and d/c = 1/4~3/7.

That is, the blending ratios of b/a and d/c, including the optimal ratios listed above (1) to (liDK), define the preferred range of molecular rigidity.In other words, the (B) component and O)) component is a rigid component, (C) component is a slightly singing component, (A) is the softest component, but (B) and
If an attempt is made to synthesize a polyimide consisting only of such rigid components, it will not be possible to obtain a polyimide with a high molecular weight due to the precipitation polycondensation system. Furthermore, since the produced polymer does not dissolve in phenolic solvents, it becomes difficult to perform spinning. However, polyimides consisting only of soft components such as (A) and (C) are easily dissolved in solvents and can be easily spun, but the resulting fibers are soft. Furthermore, it is preferable to select the ratios of b/a and d/e to define a suitable range of molecular rigidity.

In this regard, it should be noted that conventional polyimide fibers have high strength and
The reason why high elasticity cannot be obtained is thought to be due to insufficient molecular rigidity.

In the present invention, according to the blending ratios (1) to 011), after spinning using a phenolic solvent and heat treatment, an initial elastic wheel of 400 fI/A or more and a tensile strength of 1
In addition to being able to obtain polyimide fibers with a P/d or higher, it has generally high levels of strength and elastic modulus, as well as excellent heat resistance, It acidity, 1, moisture resistance, and light resistance. polyimide fibers can be obtained.

Here, the expression "excellent in light resistance" means that it is superior to aromatic polyamide (trade name: Kevlar) ti, which is currently the only commercially available high-strength, high-elastic fiber. The reason for the poor light resistance of polyamide fibers is that the N-H bonds in the amide bonds are easily broken by light, which becomes an initiation reaction and causes a photodegradation chain reaction. It is thought that it has high resistance to light because it does not contain it. The copolyimide that is the raw material for the polyimide fiber of the present invention is composed of the aromatic diamine component and the aromatic tetracal. It can be produced by polycondensation of phosphoric acid components in a solvent. The method can be said to be the same as the method described in Japanese Patent Application No. 173394/1983.

The polycondensation reaction can be carried out either in a continuous operation or in a patch operation. As the polycondensation reaction apparatus, various types such as a stirring tank type and a kneader-mixer type can be used. The reaction must be carried out with air and moisture excluded. Furthermore, in order to discharge water produced in the condensation reaction out of the system, it is useful to flow dry inert gas (for example, high-purity nitrogen gas) into the reaction system. If the solvent or raw materials are solid at room temperature, they are supplied as solids to the reaction vessel, and then
The reaction solution can also be prepared by gradually heating and melting it. Alternatively, a method can also be used in which a solid solvent is heated and melted, and the aromatic diamine component and the aromatic tetracarzenic acid component are added thereto and dissolved.

Examples of solvents used in the above solution polycondensation reaction are:
p-chlorophenol, phenol, m-cresol,
Mention may be made of p-cresol, 2,4-dichlorophenol or mixtures thereof. Moreover, at this time, p-hydroxybenzoic acid can also be added as a reaction promoting agent. The monomer concentration in the reaction solution is preferably in the range of 2 to 15 parts by weight.

The reaction temperature varies depending on the boiling point of the solvent, but is generally preferably 160 to 210°C.

The reaction time is preferably several hours to several hundred hours.

The logarithmic viscosity (molecule Jl) of the polymer (copolyimide) produced by the above reaction increases with the ashing time. In order to produce polyimide fibers with excellent physical properties,
Preferably, the polyimide of the material is a high molecular weight polymer. However, if the increase in molecular weight is set to 0 and the reaction time is made longer, it is undesirable because R is generated.

After the reaction is completed, the reaction solution is diluted with methanol, ethanol,
Pour into a precipitation solvent such as acetone or a mixture thereof,
Separate the polymer and solvent by stirring vigorously. This polymer is passed through the mouth, washed and dried. In order to obtain polyimide fibers with high elasticity and high strength, which is the object of the present invention, the polyimide obtained as described above has a logarithmic viscosity (1, V).
must be 1.5 dll or more. l,
Polymers with low V tend to break during spinning and hot drawing operations, and the resulting fibers do not have sufficient strength. Furthermore (1,
V) is an abbreviation for intrinsic viscosity, and logarithmic viscosity is generally used as an approximate value of intrinsic viscosity. The conditions for measuring logarithmic viscosity in the present invention are as follows.

Solvent: Concentrated sulfuric acid 99-100 Polymer concentration: 0.5 t/d7! Measurement temperature: 30° C. The logarithmic viscosity is calculated from the measured value using a Cannon-Fenske viscometer using the following formula.

I, V = Lln (-) et.

However, C: Polymer 8 degrees '1fld7! ln=Natural logarithm t: Flowing time of the sample solution to: Flowing time of the solvent Next, the copolyimide powder produced as described above is dissolved in a phenolic solvent to prepare a dope (spinning stock solution). It can also be used as a dogu solution. Examples of the phenolic solvent used in the production of Dogue's solution include phenol, p-/lorphenol, m-cresol, p-cresol, or mixtures thereof. Preparation of the dope solution by dissolving the copolyimide is preferably carried out by kneading under reduced pressure while heating to 50 to 120° C. using a stirring tank or a kneader.

Next, the dope liquid is discharged into the air through a nozzle using a known wet spinning device and formed into a filament. 0.5
The filament passing through the air layer of CrII to 53 is
The fibers are introduced into a coagulation bath and wound up on a winder as fully coagulated fibers. As the coagulation bath, use a solvent that is compatible with phenolic solvents, such as methanol, ethanol, or a mixture of these alcohols and water, and that is insoluble in copolyimide. Due to vapor pressure, the temperature is often set at 60°C or lower.

Generally, room temperature or lower is preferred. The length K of the coagulation bath is not particularly limited, but in general, a length of several tens of meters to several meters is used for spinning, dried fibers, electric furnaces,
Alternatively, it is hot-stretched using a hot pin or the like. This hot stretching operation can be performed by a known technique. As for the hot stretching conditions, it is desirable to perform the stretching operation at a temperature of 250 DEG C. to 420 DEG C. for 15 seconds and a stretching ratio of 2.0 times or more. The heat treatment temperature is particularly important for the polyimide fibers of the present invention, and it is desirable to perform the treatment at as high a temperature as possible. The fiber properties were measured by a monofilament tensile test according to JIS-Lj069K. The tensile tester used was manufactured by Shinko Tsushin Kogyo, and the tensile speed was 1° fin/min.

Next, the FIJJ of the present invention will be explained in more detail with reference to Examples.

Example 1 Polyimide was composed of 3,4'-diamin diphenyl ether (DADE) and tri-phenylene diamine (PPD) as the amine component, and 31 as the acid component.
"lc4'-biphenyltetracarbyl anhydride (B
The ratio of these components is DADE:P
PD:BPDAy7:a:10 Nocopoly-imide was prepared.

4 tube 3o equipped with stainless steel stirring rod, nitrogen gas inlet, nitrogen gas outlet and sample input port.

tag Seno 4' Ufruy Lasconi BPDA 7.355
Add 5P (0,025 mol) and 174.2P of phenol, and stir for 30 minutes while heating to 60°C in an oil path under a nitrogen stream. JJADE' during the next event 3.
502 s y (0,0175 mol) and PPD O,8
111? (0,0075 mol) was added and at this temperature 1.
Stirred for 5' hours. Then, 8.625y of p-hydroxybenzoic acid (PHBA), a polymerization aid, was added to this reaction system.
(0,0625 mol) was added. Next, the temperature of the oil bath was raised to 175°C over about 1 hour to start the polyimidation reaction. As the bath temperature rose, the turbidity of the reaction solution disappeared and became a brown transparent liquid as time passed. As time went on, it became viscous.

Polymerization was carried out for 32 hours while stirring at a bath temperature of around 175°C. This polymerization solution was poured into methanol, pulverized with a mixer, and washed three times with a large excess of methanol, and then the polymer was taken out and dried at 100° C. under vacuum.

A yellow powdery polymer was obtained with a yield of ioo#I.

This polymer was added to Q, 100 mm H2 at a concentration of 5 ff/di.
It was dissolved in SO4 and its logarithmic viscosity (I, V values) were completely measured at 30°C using a Cannon Fenske viscometer.2. It was s 1 dt/y.

FIG. 1 shows the infrared absorption spectrum of this polymer measured by the film method.

Table 1 shows the elemental phase separation results of this polymer.

Table 11) Results of cumulative analysis of ADFJ/PPD(7/3)-BPDA copolyimide Table 2 also shows the results of this f IJ mom thermobalance measurement. In air using a Devon 951 thermobalance device,
Measurement was performed at a heating rate of 5° C./min.

Table 2 Thermobalance measurement results Example 2 8 parts of the polyimide powder produced in Example 1 and 92 parts of p-chlorophenol were placed in a rubble flask equipped with a Teflon stirring blade, and heated to 90°C. Stirring was carried out for a period of time to prepare a homogeneous viscous solution. Add this solution to 110
After degassing under reduced pressure for 2 hours at 8ONIHg at ℃,
wire mesh, stainless steel non-woven fabric (20 μ absolut
A spinning stock solution (dope) was prepared by passing through a pressurized filter using a filter combined with e). This dope was charged into the nozzle holder of the wet spinning device shown in Figure 1, and the discharge temperature was 120°C.
, a nozzle (pore diameter 0.15
m, 1 hole) and after passing through about 2 sub-air layers,
Construct an ethanol coagulation bath (effective column length 5 m), 18.
It was wound up at a speed of 9 m/1 nIn. The speed of the dipping roller is 17. I set it to Vmin. This fiber was soaked overnight in methanol as Zevin, washed, and then washed. This undrawn yarn was hot-stretched using the hot-stretching device shown in FIG. 2 to obtain high-strength, high-elasticity fibers as shown in Table 3. The stretching ratio was calculated using the following formula.

(Stretching ratio) = (Fineness of undrawn yarn) / (Fineness of hot drawn yarn) Table - 3DADF/PPD (7/3) - Example 3 of BPDA copolyimide fiber 3.4'-Diaminodiphenyl ether (DADE) 3,3',4,4'-diphenyltetracarboxylic anhydride (BPDA) and pyromellitic dianhydride (P
Copolyimide fibers with a loading ratio of MDA) of 10Nia:3 were produced.

BPDA 5.1489 P (0,
0175 mol) and PMDA 1.6359 F (0,
OO (75 moles) and phenol 176.151' were charged and stirred for 30 minutes while heating to 60° C. under a nitrogen atmosphere. Next, add DADE 5.006 I to this solution.
After adding P (0,0025 mol) and continuing stirring for 1.5 hours, PHBA8.6255' (0,062
5 mol) and raise the oil bath temperature to 175°C.

In this reaction system, the liquid becomes viscous over time. Some turbidity was observed in the liquid. After heating and stirring for 30 hours, the reaction solution was poured into methanol in the same manner as in Example 1 and pulverized with a mixer to recover the polymer. Yield 10.8 f
f.

Yield 99%. The I and V values of this polymer are 1.96 d4
/? Met.

FIG. 3 shows the infrared absorption spectrum (taken by the film method) of this polymer. In addition, the elemental analysis values of this polymer are shown in Table 4.

Table 4: The results of thermometric measurements of this polymer of DADE-BPDA7PMDA (7/'3) copolyimide are shown in Table 5 - The measuring equipment and conditions are the same as those shown in Example 1.

Table 5 Results of thermobalance measurements 9 parts of this polyimide powder and 91 parts of p-chlorophenol were heated, mixed, stirred and dissolved to prepare a spinning dope. Wet spinning and hot stretching were performed in the same manner as in Example 2 except that the discharge temperature was 110°C. The obtained fiber properties are shown in the table below.

Table 6 Tensile test results for copolyimide fibers Example 4
A copolyimide consisting of PPD, BPDA, and PMDA in a ratio of 8:2:8:2 was prepared. BPDA 5.884
411 (0,020 mol) and PNDA 1.0906p
After adding (0,005 mol) and phenol, DADK
4.0048F (0,020 mol) and PPD 0.54
Add 07 ff (0,005 mol) and further add PHBA
6.900 P CO0.05 mol] was added and the bath temperature was 175
Polyimidization was performed at around ℃ for 66 hours, ■, v value 2,
A polymer of 0.02 dt/11 was obtained. A spinning dope was prepared from 8 parts of this polyimide powder and 92 parts of p-chlorophenol. Discharge temperature 90℃, nitrogen pressure 2.8 ki/
Err? Spinning in the same manner as in Example 2 except for a.
Hot stretched. The obtained fiber properties are shown in the table below.

Table 7 Tensile strength test results for copolyimide fibers Example 5 D
T) copolyimide consisting of ADE, PPD and BPDA
They were manufactured by changing the ratio of ADE and PPD. Phenol was used as a polymerization solvent, and PHBA was used as a polymerization aid. The amount added was twice the molar amount of the amine component. The results are summarized in the table below.

3.4' -DADE : PPD : BPDA -
A spinning dope was prepared with 8 parts of polyimide powder of 9:1:10 and 92 parts of p-ria siphenol. Discharge temperature 90℃, nitrogen pressure 2.2 kg/lyr? The spinning and hot stretching were carried out in the same manner as in Example 2, except that G was used. The obtained fiber properties are shown in Table 9. Regarding the other three polyimide P, 8 parts of their powder and 92 parts of p-chlorophenol were added.
Dawg for spinning was prepared using the above-mentioned parts, and subjected to spinning and hot stretching. However, 3.4' -DADE : PPD : BPDA -
8: 2: 10 discharge temperature is 100℃, nitrogen pressure is 2.8 kf/crr? When using G and 6:4:10, it is 90℃, 3'f/crr? G5: 5:10
In the case of 90℃, 2.8 kg/cn? The spinning conditions were set to G. The obtained fiber physical properties are shown in Tables -10 to -12.

Table-93,4'-DADE:ppI): BPDA
= 9:1:10&-103,4'-DADE:
PPD: BpDA=8:2:10 table-113,4'
-DADK: PPD: BPDA failure 6:4:10
Tensile test result table of copolyimide fiber-123,4'-DADE: PPD: BPD
A = 5:5:10 Example 6 DADE was prepared in a similar manner using the apparatus described in Example 1.
A copolyimide with a ratio of BPDA and PMDA of 8:2 was produced. Phenol was used as the polymerization solvent, and the monomer concentration charged was 5wt1. Further, p-HBA was used as a polymerization aid, and the amount added was 2.0 times the mole of the amine component. 1 like this
The reaction was carried out for 43 hours at a bath temperature of around 175°C under the conditions of 1. v
Value 2.25d/! /7 :ff polyimide was obtained.

A spinning dope was prepared from 8 parts of this polyimide powder and 92 parts of p-chlorof-nol. Discharge temperature 100℃, confinement pressure 2.4 kg/err? The spinning and hot stretching were carried out in the same manner as in Example 2, except that G was used. The obtained fiber properties are shown in the table below.

Table-13 Example 7 DADE, PPD and BPDA (DADE/D-7
/3) When producing Codeliimi V, polymerization was carried out without adding p-HBA as a polymerization aid. Phenol is used as the solvent, and the IIl! The polymerization apparatus, polymerization method, conditions, etc. are the same as those described in Example 1, except that the concentration is 5 wt%. As a result, the combined time is 62
A copolyimide with a t and v value of 2.27 #/p was obtained.

Example 8 Continuing with this example, a cylinder consisting of ADE, PPD and BPDA,
When producing a copolyimide with a charging ratio of DADE and PPD of 8:2, PCP was used as the polymerization solvent, and the resulting polymerization solution was poured into a large excess of methanol without post-treatment. This is an example in which a copolyimide fiber was produced by direct spinning and further hot drawing.

BPDA 5.8844 f in the apparatus described in Example 1
? (0.02 mol) and PCP 126.5 F were added under heating at 75°C under a nitrogen gas stream, and after 30 minutes, K DADE 3.2039 t (0,016 mol) was added.
and PPDo, 4326P (0,004 mol) was added,
After stirring for 1.5 hours p-HBA 5.52 F! (0,0
4 mol) was added thereto, and the bath temperature was raised to around 175°C over 1 hour to initiate polymerization. Monomer preparation concentration is 7w
It was t4.

After carrying out polymerization for 16 hours at this aK, the obtained brown transparent polymerization liquid was passed through the mouth as it was, defoamed, and packed into a spinning strip, and spun and hot-stretched by the method shown in Example 2. Discharge temperature 100
°C, nitrogen pressure 3 k/j/crr? It was set as G.

A portion of this polymerization solution was sampled and the copolyimide I and V values obtained after treatment were measured and found to be 3.36 d//
It was 4.

Table 14 Comparative Example 1 Using the apparatus described in Example 1, DA was carried out in the same manner.
A polyimide consisting of DE and BPDA 25- was produced.

Both monomer components were prepared so that the monomer concentration was 6wt, and 9.5% of phenol was added in the presence of p-HBA.
Polymerization was carried out for a period of time to obtain a polyimide with I and V values of 2.64 dt/f(1').

A spinning dope was prepared from 8 parts of this polyimide powder and 92 parts of p-chlorophenol. Discharge temperature 120℃, nitrogen pressure 2.2 kP/crr? The fiber labeled G was spun and hot-stretched in the same manner as Example 2. The obtained fiber properties are shown in the table below.

Table 15 Comparative Example 2 Using the apparatus described in Example 1, DADE was
Consists of BPDA and PMDA, BPDA and PMDA
A copolyimide with a ratio of 9=1 was prepared and phenol was produced in the presence of p-HBA at a monomer concentration of 5wt4.
After 9 hours of polymerization, a copolyimide with a v value of 2.13 was obtained.

A spinning dope was prepared from 8 parts of this polyimide powder and 92 parts of p-chlorophenol. Discharge temperature 90℃, nitrogen pressure 3.2 kg/1w? The spinning and hot stretching were carried out in the same manner as in Example 2, except that G was used. The obtained fiber properties are shown in the table below.

Table 16 Comparative Example 3 DADE was carried out in the same manner using the apparatus described in Example IK.
It is composed of PPD and BPDA, and the ppm ratio of DADE is 4.
A copolyimide of =6 was prepared in the presence of p-HBA.

The monomer concentration charged was in relation to S wt. Polymerization progressed heterogeneously, and after 120 hours of polymerization, ■, v, value 2, 2
A copolyimide of 6 dl/f was obtained. In order to make fibers from this polymer, an attempt was made to manufacture Dogue by dissolving it in 8 parts of polymer and 92 parts of PCP using the method described in Example 2, but the polymer did not dissolve in PCP, resulting in uneven doping and spinning. It was impossible.

Comparative Example 4 DADE was produced in the same manner using the apparatus described in Example 1.
A:lff polyimide composed of BPDA and PMDA with a ratio of BPDA to PMDA of 6:4 was prepared in the presence of p-HBA at a monomer concentration of 5 wt%. The polymerization reaction proceeds heterogeneously, and the awaited copolyimide I and V
, the value was as small as 0.73 dt/FI, and spinning was impossible.Example 9 The present invention shows that the /limide fiber of the present invention has excellent light resistance. The polyimide fiber used in this example is DA
This is a heat treatment system consisting of DE-PPD-BPDA (composition strength: 7:3:10). For comparison, aromatic polyamide fiber Kevlar 49 was tested at the same time.

The test equipment used was a Weather-Ometer MIQ-1 model manufactured by Toyo Seiki Co., Ltd., which was partially modified.
This shortens the distance between the sample and the light source and increases the intensity of the light hitting the sample. That is, 600 at the center of the above device.
An aluminum cylinder (about 20 Crn in diameter and 33 Crn in height) is placed around a 0W xenon arc lamp, and 7 to 10 polyimide fibers each having a length of about 15 (7) and a polyamide fiber for comparison are placed on the inner wall of this cylinder for a predetermined period of time. Tensile tests were carried out on single fibers by cutting samples for several minutes. Note that the surface temperature of the aluminum cylinder reached approximately 100°C.

No water injection was performed on the sample. The deterioration of fibers is primarily due to the action of light. The aromatic polyamide fiber used in the comparative test was soaked with methanol, water and n-
It was used after washing with hexane.

The test results are shown in Tables 17 and 18.

From these tables, Kevlar 49 has an intensity of 5.2 after 24 hours of irradiation! The polyimide fiber of the present invention has a strength retention ratio of 17.4 even after 24 hours, although the strength retention ratio is only 20%.
It has a strength of 51/d and a strength retention rate of 84.

Although the specification of Japanese Patent Application No. 173394 states that polyimide fibers using tolidine have better light resistance than Kevlar 49, the present invention is based on the specification of Japanese Patent Application No. 173394.
The light resistance of the polyimide fiber described in I. Lu is further improved.

Table 17 Results of light resistance test of polyimide fiber Table 18 Results of light resistance test of polyamide fiber (Kevlar 49) Example 1O This example shows the results of a dry heat degradation experiment of fiber.

3.4'-DADB: PPD: BPDA=7
: 3 : 10 hot drawn yarn under constant tension (0,341
1/d) and wrap it around the frame.

In that state, it was placed in the open at 300°C. After the specified time has passed, remove it from the open and let it cool.

Strength and elongation were measured. For comparison, commercially available Po17-
Similar experiments were conducted with p-7 enylene terephthalamide fiber (DuPout, Kepler 49). The results are shown in the table below.

Table 19 Example 11 This example shows the results of a wet heat deterioration experiment on fibers.
, 3.4'-DADE : PPD : BPDA=
7:3:10 hot drawn yarn under constant tension (0,3
4#/d) around a frame, and in that state was placed in an autoclave and subjected to steam treatment at 200°C. After a predetermined period of time had elapsed, it was taken out of the autoclave, allowed to cool and dry, and then its strength and elongation were measured. For comparison, a similar experiment was conducted on Kepler-49. The results are shown in the table below.

Table 20 Example 12 This example shows the results regarding the acid resistance of the fibers. 3.4'-DADE: PPD: BPDA=7
: 3 : 10 hot-drawn yarns are mixed with 40 sulfuric acid aqueous solution and 4
The sample was immersed in a 0% aqueous acetic acid solution and treated at 85°C for a predetermined time.

after that.

After repeated washing with water and methanol, strength and elongation were measured after drying. For comparison, a similar experiment was conducted on Kepler-49. The results are shown in Table 21-22.

Table 2140 Thisulfuric Acid Aqueous Solution Table 2240% Acetic Acid Aqueous Solution [Effects of the Invention] The polyimide fiber of the present invention is manufactured from conventional polyimide dough. T? Compared to polyimide fibers, it has significantly improved strength and elasticity, and also exhibits excellent light resistance. Furthermore, as demonstrated in the Examples, excellent properties can also be exhibited in terms of chemical resistance (acid resistance), steam resistance, and heat resistance. Also,
Polyimide fibers exhibiting such excellent VC properties can be produced stably and with good reproducibility, particularly by the method for producing 4-limide fibers of the present invention.

[Brief explanation of the drawing]

FIGS. 1 and 3 are diagrams showing infrared absorption spectrum curves of the polyamide according to the present invention produced in "Example". FIG. 2 is a schematic diagram showing an example of a spinning device used in the present invention. 1... Nitrogen cylinder, 2... Nitrogen intermediate distiller, 3... Pressure gauge. 4... Nozzle holder ~, 5... Nozzle, 6... Coagulation bath. 7... Guide, 8... Dipping roller, 9... Winding bobbin, 10... Temperature controller.

Claims (6)

[Claims] (1) A polyimide fiber having one repeating unit derived from an aromatic diamine component and an aromatic tetracarboxylic acid component, the aromatic diamine component having the following formula (A)
The aromatic tetracarboxylic acid component is composed of a mole of component of formula (B) as required and b mole of component of formula (B) as required.
Consisting of C mol of component C) and d mol of component 2) if necessary, and a+bwe+d, % b/a is in the range of O to 1, and d/c is in the range of θ to 3/7 ( However, b and d do not become O at the same time.) A polyimide fiber characterized by: /\ C〇 complete set (D): (2) The polyimide fiber according to claim 1, wherein d=O and J) b/a is in the range of 1/9 to 1. (3) The polyimide fiber according to claim 1, which has a b-0 thickness and a d/e thickness of 1/4 to 3/17. (4) b/m is in the range of 1/9 to 3/7, d/e is in the range of 1/9
Claim No. 4 to 3/7 (the polyimide fiber according to claim 0). (5) The polyimide fiber according to any one of claims (1) to (4), which has an initial elastic modulus of 400 ffA or more and a tensile strength of 13 Vd or more. (6) A copolyimide having a repeating unit derived from an aromatic diamine component and an aromatic tetracardic acid component, wherein the aromatic diamine component is a mole of the component of the following formula (A) and, if necessary, the formula Composed of b moles of component (B), the aromatic tetracardic acid component is represented by the following formula (C):
consisting of component C moles of and optionally d moles of component
and d/c is in the range of O to 3/7 [However, b and d are never O at the same time. ], the logarithmic viscosity is 1
．． A dope is prepared by dissolving a copolyimide of 5 or more in a phenolic solvent, and this dope is discharged into the air through a nozzle to form a filament. Polyimide fibers characterized by introducing the fibers into a copolyimide-insoluble coagulation bath to coagulate the fibers, then winding them up, washing and drying them, and then hot-stretching them at 250 to 420°C to double or more. Manufacturing method for 7 people