JPS63309641A - Blended spun yarn excellent in shape stability at high temperature - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of the Invention] The present invention incorporates aromatic boliabad fibers, which have excellent shape stability and melt resistance at high temperatures, into the main fiber, thereby reducing the heat resistance of the main fiber. This is an attempt to effectively resolve the shortcomings.

This method can be used for various purposes without significantly changing the properties of the main fiber. For example, it can be applied to sportswear that prevents melting due to frictional heat, various types of protective clothing such as firefighting suits that prevent shrinkage due to heat during combustion, and various living items that prevent punctures caused by cigarette burns.

[Prior art]

As heat-resistant fibers, meta-aromatic polyamide fibers whose chemical composition is mainly composed of polymetaphenylene inophthalamide (hereinafter abbreviated as PMIA) are widely used. However, this fiber has insufficient morphological stability at high temperatures above its melting point. Therefore, it has even been proposed to incorporate a small amount of para-based aromatic polyamide fiber. However, para-aromatic polyamide fibers have high rigidity,
Since the fiber elongation is also low, it has the drawback of significantly reducing flexibility and post-processability as a clothing fiber.

Furthermore, PMIAljll fibers have poor post-dyeability, and when mixed with other main fibers, they have the disadvantage that vivid dyeing cannot be achieved.

[Means to be solved by the invention]

The present invention mainly uses aromatic polyamide fibers having the following characteristics (1) to (6) in order to effectively solve the drawbacks of the main fibers against heat without significantly changing the properties of the main fibers. It has been found that by blending edge MK, it is possible to obtain a blended yarn that covers the defects of the main fiber and has excellent shape stability at high temperatures.

That is, the present invention provides 5 aromatic polyamide fibers having characteristics satisfying the following formula.
~70% by weight blended yarn, Tm5350℃
(1) Tm-Tex≧30°C
(2) Xc≧10chi (8) DE≧
10% (4) DSR (Tm
)≦15% (5).

In the present invention, the aromatic polyamide fiber blended with the main fiber is almost the same as existing organic synthetic fibers, such as polyethylene terephthalate fiber, as shown in the characteristic values and physical property values of (1) to (6) above. Balanced general fiber performance represented by strength, elongation, and Young's modulus, and performance that existing heat-resistant organic synthetic fiber PMIA fiber does not have.
In other words, it has excellent morphological stability, with small thermal shrinkage even at high temperatures above the melting point, and the fibers do not firmly fuse together even when burned.

To explain these formulas (1) to (6), Tm (melting point) is 350°C or higher, and Tex (exothermic onset temperature) is 30°C or lower (Xc (crystallinity) is 10% lower than Tm).
When it is above, the fiber has excellent shape stability even at high temperatures above the melting point.

In other words, 'rm≧350℃ and Xc≧10%
Even if Tm-Tex is 30°C or higher and T
Comparing fibers with m-Tex of less than 30°C, the former, that is, Tex (thermal decomposition initiation temperature) is lower than Tm (melting point), 1
The one lower than 0℃ is the latter, that is, Tex is 930℃ lower than Tm.
This means that fibers with a temperature of less than 50% have better morphological stability at high temperatures that are higher than the Tm (melting point) of the fiber. This may seem absurd, but surprisingly, it actually turns out to be T.
The lower the ex, the better the shape stability.

I don't know the exact reason for this, but Tm53
In aromatic polyamide fibers where 50°C, Xc≧10 and Tex is 30°C or more lower than Tm, thermal decomposition starts from a relatively low Tex, so it occurs slowly and mainly in the amorphous region, and at that time, Since the microcrystals exist without melting in the crystalline region, the shrinkage is suppressed because the microcrystals act as restraint points for the molecular chains against thermal contraction that occurs when the orientation of the oriented molecular chains in the amorphous region is relaxed due to heat. Tsutsu,
It is thought that a type of crosslinking occurs between molecular chains as a result of the thermal decomposition reaction that proceeds simultaneously, forming a three-dimensional structure, resulting in good morphological stability even above the melting point.

On the other hand, even if Tm is 5350°C and Xc≧lO%, if Tex is lower than Tm by only 30°C, thermal melting will occur before a three-dimensional structure is formed due to sufficient intermolecular crosslinking. It is thought that thermal shrinkage and fusion between fibers increased, resulting in poor shape stability.

Therefore, the range of Tm-Tex is Tm-Tex530℃
Preferably Tm-Tex≧50°C, more preferably Tm-Tex≧70°C.

In addition, other fiber properties deteriorate to some extent at Tm or higher, so in order to be a heat-resistant fiber that can be used even at temperatures 9200°C or higher than general synthetic fibers, Tm must be 350°C or higher, which is preferable. is Tm≧400°C or higher, more preferably Tm≧420°C or higher.

In addition, even if Tm≧350℃ and Tm-Tex 230℃, if the crystallinity is small (XC<10), there is almost no restraining effect on molecular chain movement due to microcrystals, so the glass transition point is much lower than Tm. As a result, thermal shrinkage rapidly increases and shape stability becomes poor.

For these reasons, it is necessary that Xc≧10chi,
Preferably, Xc≧15, and the fiber is for clothing;
In order to be used in the same way by blending with existing organic synthetic fibers in industrial materials, etc.
Processability and dyeability are essential conditions. For this purpose, it is important to have a sufficient balance between strength and elongation, especially elongation, and DE (fiber elongation) must be 10 inches. Preferably DE)15, more preferably pg>2o=1. In addition, as an aspect to further improve the shape stability at high temperatures, the fiber has DSR (Tm).
≦15 and DSR (Tm + 55°C) DSR (Tm) ≦3 must be satisfied.

If the DSR (Tm) exceeds 15%, dry heat shrinkage is already large at the melting point, and the shape stability cannot be said to be good. Even if DSR(Tm)≦15'16, DSR(Tm
+55℃) DSR (Trn) In the case of 〉3, the thermal contraction increases rapidly when the melting point is exceeded, so if you are wearing heat-resistant protective clothing and are damaged by an earthquake, it will be difficult to take it off and you will suffer more damage such as burns. There are 6 things I like and don't like.

I wanted to-CDSRσI'm+55'C)-DSR(T
m) It is important that the heat shrinkage is sufficiently small even at higher temperatures than the melting point of +55°C as shown in ≦3. When blending such heat-resistant aromatic polyamide fibers with the main fiber, If the fiber is a thermoplastic fiber, for example, jllll
Blended yarns and yarns that can exhibit heat-insulating effects, and when the main fiber is heat-resistant, blended yarns and yarns that can exhibit dimensional stability effects at high temperatures, and when the main fibers are flame-resistant fibers. This results in a blended yarn that not only improves dimensional stability but also exhibits the effect of improving flame retardancy.

Note that the characteristic values and physical property values of the aromatic polyamide fiber in the present invention represent values obtained using the measuring equipment and measuring conditions described below, respectively.

Tm: Melt failure: Approximately 10 or more samples were placed in an A1% sample dish using DSC-2C manufactured by PerkinElmer and heated at 10℃ per minute from room temperature to a predetermined temperature in a nitrogen gas stream (30*l/m1n). Obtain the DSC curve up to and let its endothermic peak temperature f: Tm.

Tax: Heat generation start temperature; PerkinElmer dDsc
At -2C, put about 10 cm of sample into an AtU sample dish in an air stream (30 ml/min) at 10°C per minute, draw a DSC curve from room temperature to the required temperature, and let the temperature at which the heat starts to heat up to Tex. .

Crystallinity: Xc; Rotating anticathode ultra-high intensity X-ray generator iRA D-rA (40KV 100mA, manufactured by Rigaku Denki ■)
(CuKz ray), obtain an X-ray diffraction intensity curve in the range of diffraction angle 2θ = 5 to 35 while rotating the sample in a plane perpendicular to the X-ray beam, and then divide the diffraction curve into a crystal region (Ac). Separated into amorphous region (AA'), value Xc calculated from the following formula
Let be the crystallinity.

X c = -X 100 (chi) Ac-)-Aa DE: Elongation of fiber; using an Instron tensile tester, sample length 10 cm, tensile speed scm/min, initial load 0.05 f
It was determined by conducting a tensile test under the conditions of /d.

DSR: Dry heat shrinkage rate; after applying a load of 0.1 f/d to the fiber sample and measuring its length to, it is free-treated in a hot air dryer at a predetermined temperature for 10 minutes, and then 30 minutes later, Q
, if/d was applied to measure the sample length t1, and the dry heat shrinkage rate DSR was determined by the following formula.

DSR=-xlOOchi t.

The aromatic polyamide fiber represented by the above-mentioned specific physical properties has, for example, carbon atoms 1 to 4 at the ortho position of the phenylene group directly connected to the nitrogen atom and/or carbon atom of the amide bond.
It is a fiber made of aromatic polyamide having a lower alkyl group, or a functional group selected from amine group, sulfone group, carboxyl group, hydroxyl group, etc., or a halogen atom.

The substituent present at the ortho-position of the phenyl group of the aromatic polyamide may be any substituent as long as it satisfies the physical properties of the fiber, but those described above are preferred. More preferred are lower alkyl groups having 1 to 4 carbon atoms.

The method for producing aromatic polyamide fibers having such specific physical property values is not particularly limited, but for example, as described in Japanese Patent Application No. 117970/1987 filed separately by the present inventors, At least 95 moles of repeating units are 4-methyl-1,3-phenylene terephthalamide and/or 6-methyl-1゜3-phenylene terephthalamide, and 6.6 mmolth is used as the spinning stock solution, and the stock solution temperature is is maintained at 20 to 150°C, preferably 40 to 100°C, and metal salts such as Caαz, ZnQ! z, Lto2
Wet spinning is carried out in an aqueous solution containing 10 to 50 wt% of LiBr, etc. at a temperature of 30 to boiling point temperature and 50 to 100 °C, and then in an aqueous solution bath with almost the same composition as the coagulation bath. 50 to 100
℃After thorough washing in hot water, 100-200℃
It is manufactured by drying with hot air at 300° C. to 450° C. and then performing a dry heat stretching heat treatment of 1.1 to 5 times in air or an inert gas bath at 300° C. to 450° C.

Depending on the properties of the coagulation bath during wet spinning, it is possible to form unevenness on the surface of the resulting fiber, and if the fiber has such an uneven surface, it will have a good effect on its spinnability. I can do it.

〔Effect of the invention〕

There are no particular restrictions on the fibers to be blended with the aromatic polyamide fibers used in the present invention. When the main fiber is a heat-resistant fiber, the dimensional stability at high temperatures is further improved,
In the case of flame-retardant fibers, the main objective is to improve flame retardancy in addition to improving dimensional stability, and in the case of thermoplastic fibers, the main purpose is melt-proof processing using frictional heat.

In particular, the aromatic polyamide fiber used in the present invention has a lower alkyl group having 1 to 4 carbon atoms, an amino group, a sulfone group, or An aromatic polyamide with a functional group selected from carboxyl groups, hydroxyl groups, or halogen atoms! In the case of a fiber manufactured by I.L., it has better post-dyeability than PMIA fiber, so it is particularly useful as a clothing fiber without impairing the dyeability of the blended yarn. As described above, the blended yarn mixed with this aromatic polyamide fiber, which has dimensional stability and dyeability at high temperatures, can have heat resistance without impairing dyeability. Therefore, its application range is extremely wide.

Next, the eclipse mode of the present invention will be specifically explained with examples, but the present invention is not limited to these examples.

Example 1 Production of aromatic polyamide Terephthalic acid 166, Of' (0,9991 mol), and monopotassium terephthalate were placed in a 3-capacity separable flask equipped with a stirrer, thermometer, condenser, dropping funnel, and nitrogen introduction tube. salt 2.038i/, anhydrous N,N'-dimethylethyleneurea 1600ml. was charged under a nitrogen atmosphere and heated to 200°C with stirring on an oil bath.

While maintaining the contents at 200°C, a solution containing 174.0f (0,9991 mol) of tolylene-2,4-diisocyanate dissolved in 160 ulK of anhydrous N,N'-dimethylethylene urea was added dropwise from the dropping funnel over 4 hours, and then After continuing the reaction for an additional hour, heating was stopped and the mixture was cooled to room temperature. A portion of the reaction solution was poured into strongly stirred water to precipitate a white polymer, which was further washed with a large amount of water and dried under reduced pressure at 150°C for about 3 hours. The logarithmic viscosity of the obtained polymer was ,1? /d, / , 30
°C) was 2.2. The polymer concentration of the polymerization solution is about 11.0% by weight, and the viscosity of this solution is 420 voids (
Type B viscometer; 50°C). In addition, the obtained polymer showed a difference in IR spectrum and NMR spectrum (4
-Methyl-1,3-phenylene terephthalamide).

The above polymerization solution is degassed under reduced pressure at 50° C. to prepare a spinning dope that does not contain air bubbles. Then, while maintaining the temperature at 50°C, the pore diameter Q and l1
w, 54. into an aqueous coagulation bath containing 240% Caα maintained at 80°C through a nozzle with 600 holes (6 holes are circular).
Discharge at 41'/min. The filament discharged from the nozzle passes through a coagulation bath, and then is subjected to moist heat stretching in a bath with the same composition as the coagulation bath at a rate of about 1.6 times, and is thoroughly washed with water in a washing bath consisting of 80°C warm water. An oil agent is applied thereto, and the fiber is dried through a hot air tank at 150° C. to obtain a wet heat drawing method spun yarn.

The spinning yarn has an oval cross section but is homogeneous and has a diameter of 2900
It was a denier/600 filament.

Next, this spun yarn was subjected to dry heat stretching at a draw ratio of about 2.4 times using a nitrogen flow hollow dry heat drawing machine maintained at 430°C.
Phenylene terephthalamide)") ffl fibers were produced.

The physical properties of the obtained fiber were as follows: single yarn denier = 2, strength = 5.
8f/dr% elongation = 25.4%, Young's modulus = 88f
/d%Tm=425°C, Tex=330°C, Tm-Te
x=95°C, Xc=24%, DSR(Tm)=DSR(
425°C) = 11°C, it can be seen that numerically it shows good general fiber physical properties and excellent shape and stability at high temperatures above the melting point.

The fibers thus obtained were mechanically crimped and cut into 38 baskets to produce fibers for spinning. Next, a 2dX 38 day cut polyethylene terephthalate fiber was mixed with aromatic polyamide fiber m/polyethylene terephthalate fiber at a weight ratio of 4/6, and a
A high-count spun yarn was made and woven, and a friction melting test was conducted. As a result, no holes were formed even under conditions where polyethylene terephthalate fibers were melted.Furthermore, no holes were formed even when a cigarette was directly fused to the fabric.

Example 2 Production of poly(metaphenylene isophthalamide) In a 2 t jacketed separable flask equipped with a stirrer, a thermometer, and a jacketed dropping funnel, 250.29 (1,232 mol) of isophthalic acid chloride, anhydrous tetrahydrofuran 60011/ was charged and dissolved, and the contents were cooled to 20'C by passing a refrigerant through the jacket. While stirring vigorously, add anhydrous tetrahydro 7, yn 40011VC metaphenylene diamine 133.7? (1,237 mol) was added dropwise over about 20 minutes. The obtained white emulsion was quickly poured into water (water-cooled) containing 2.464 mol of anhydrous sodium carbonate under strong stirring. Immediately, the slurry temperature rose to near room temperature. Subsequently, the slurry was prepared with caustic soda to a concentration of 11, and the resulting cake was thoroughly washed with a large amount of water and dried under reduced pressure at 150°C overnight. Logarithmic viscosity was 1.4.

Preparation of poly(metaphenylene isophthalamide) fiber The poly(metaphenylene isophthalamide) or PMIA polymer powder was mixed with N-methyl-2-pyridene (
NMP) and 2% to NMP. Then 80℃
It was discharged at 5.2 f/min from a nozzle with a hole diameter of 0.08 ta and 100 holes (6 holes are circular) into an aqueous coagulation bath maintained at 80 °C and containing 9 Caα 240 cm, and rotated at 10 m/min. The rollers are passed through a hot water bath at 80°C, thoroughly rinsed with water, and then the a-roller and rollers are stretched at 2.88 times in a hot water bath at 98°C. The yarn was dried by passing it through a tank to obtain a spun yarn that had been subjected to wet heat stretching. The spinning yarn has a homogeneous cocoon-shaped cross section,
It was 358 denier/100 filament.

Next, this spun yarn was subjected to dry heat stretching of 1.88 times on a plate at 310°C to obtain poly(metaphenylene isophthalamide) fiber.

The physical properties of the obtained fibers were as follows: single yarn denier = 2, strength = 4.
9'/d% elongation = 28.5%, Young's modulus = 80r/d
, Tm=425°C, Tex=405°C, Tm −Tex
=20℃, Xc=25%, DSR(Tm)=DSR(4
25°C) = 16%, and although this PMIA fiber exhibited good general fiber properties, it was poor in shape stability at high temperatures above the melting point.

The PM obtained in this way was machine crimped with IA woven fibers,
A 0 2/2 twill fabric was prepared by mixing the fibers cut into 38 mm and the fibers obtained in Example 1 at a weight ratio of 6:4, and obtaining a blended yarn of 30 count using the normal spun spinning method. When we conducted a combustion test, it showed self-extinguishing properties, and the burning part did not fuse and the flame did not penetrate. On the other hand, in a similar fabric made of only PMIA fibers, fusion occurs at the burning part, and that part shrinks thickly, creating a hole in the fabric and allowing the flame to pass through.

Patent applicant: RiRashi Co., Ltd. Same Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1. An aromatic polyamide having characteristics satisfying the following formula:
A blended yarn containing ~70% by weight. Tm≧350℃ Tm-Tex≧30℃ Starting temperature (°C
), Xc is crystallinity (%), DE is elongation (%), DSR
(Tm) is dry heat shrinkage rate (%) at melting point Tm, DSR
(Tm+55°C) represents the dry heat shrinkage rate at the melting point +55°C. ) 2. The aromatic polyamide fiber has a lower alkyl group having 1 to 4 carbon atoms, an amino group, a sulfone group, a carboxyl group, and a hydroxyl group in the ortho position of the phenylene group directly connected to the nitrogen atom and/or carbon atom of the amide bond. The blended yarn according to claim 1, characterized in that the fiber is made of an aromatic polyamide having a functional group or a halogen atom.