JPS5947421A - Manufacture of aromatic polyamide synthetic fiber having high young's modulus - Google Patents

Abstract

PURPOSE:To manufacture the titled fiber having extremely high Young's modulus, without lowering the strength, by extruding a concentrated solution of an aromatic polyamide in air and wet-spinning the fiber, wherein the spinning is carried out under a specific take-up tension defined by the acid content of the coagulated fiber. CONSTITUTION:A polymer of poly-p-phenylene terephthalamide composed mainly of the structural unit of formula is dissolved in a >=98wt% concentrated sulfuric acid, chlorosulfuric acid, fluorosulfuric acid or their mixture to obtain an anisotropic dope. The dope is extruded into a non-coagulating phase, passed through a coagulating phase, and taken up under a tension of 1.0-4.0g/d keeping the weight ratio of the acid in the obtained coagulated fiber to the polymer in the fiber to 0.1-0.8. The intrinsic viscosity of the poly-p-phenylene terephthalamide is preferably >=5.1, and the polymer concentration is preferably >=14wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing poly-P-phenylene terephthalamide (hereinafter abbreviated as "PPTAJ")-based wIH, and more specifically, it has an extremely high Young's modulus. , and relates to a method for producing PPTA fiber #C, which is particularly useful for reinforcing plastics and rubbers.

PPTA is a polymer that has been known for a long time, and it is already known that fibers obtained from it have a rigid molecular structure and therefore have excellent heat resistance and mechanical properties.

According to Japanese Patent Application Laid-Open No. 47-39458, an aromatic polyamide-based polymer having a limited inherent viscosity is spun using sulfuric acid as a solvent and a dope having a certain polymer concentration by an air discharge wet method. With the twisted yarn,
In other words, it is not described that there is a fiber that is soft without drawing or heat treatment and has an exceptionally high tensile strength and Young's modulus. Although it is said that the Young's modulus of the yarn is as high as 1/l i i when spinning, it is often used in composite reinforcement yarns that require particular toughness, such as those used in aircraft and space applications. When used as 7, compared to ceramics, graphite, and boron e1, the Young's modulus is red enough. Not used in f size.

To this end, the spun twisted fibers were heated under tension in order to obtain an improved, high Young's modulus fiber that would be suitable for use as a differentiated plastic composite material.
A method for further improving the Young's modulus of
No. 43419.

However, in order to make fibers that can be used for advanced laminated materials, this heat treatment method requires that the spun and KN-shaped fibers be subjected to heat treatment again, resulting in an extremely low production cost; However, heating and stretching caused a decrease in intrinsic viscosity and a decrease in tensile strength.

Kaya Kaimei 52-12325, a method for welding high Young's modulus glue fibers of aromatic polyamide with PPTA containing PPTA.
Publication of ℃ and Japanese Patent Publication No. 52-1232f'+:
), and after pre-stretching a 1-inch coagulated yarn that had been spun in the air and wet-spun, it was further heated at 300°C.
It is said that fibers with high tensile strength and high Young's modulus can be made oblique by heat treatment at a high tensile strength.

30 (1/d Q; eρ with a high Young's modulus of 10) is obtained, but in order to reduce the Young's modulus, it is necessary to increase the Young's modulus by M+stretching and heat treatment. Two steps are required and the equipment is complicated.However, since the heat treatment is carried out at a high temperature of 300°C or higher, there is a serious drawback that energy consumption is large.

In general, it is known that the Young's modulus of a fiber corresponds to the crystal orientation measured by X-axis, etc.
It has been proposed that hot drawing treatment is an effective method for improving crystal orientation. Similarly, for fibers made from PPTA, it is disclosed that the method of drawing -μ spun and qQ fibers in a heated atmosphere as described above is extremely effective in improving Young's modulus. On the other hand, in the spinning process, by increasing the tension at the time of take-off, the effect of improving crystal orientation similar to that in the drawing process can be seen, but in general, the increase in take-off tension also causes destruction of the fiber structure. It has been said that the tensile strength of the fibers is markedly lowered, especially in a wet spinning method in which a polymer solution is introduced into coagulation.

However, the present inventors investigated the coagulation state and fiber properties under various spinning conditions, especially the coagulation state and fiber properties in coagulated yarns, in order to produce fine fibers with high Young's modulus and tensile strength from concentrated sulfuric acid solutions of aromatic polyamide polymers. While investigating the ratio of acid content and the take-up tension applied to the coagulated thread, it was surprisingly found that when the ratio of acid weight to polymer weight in the coagulated thread and the take-off tension are combined within a certain range. However, as a result of further intensive study, the present invention was completed. reached.

Suwachi, Kito [! The purpose of F1 is to propose a method for efficiently and inexpensively producing fibers with extremely high Young's modulus in potash, mechanical properties, and PK from aromatic polyamides through hot stretching and other treatments. (There is.

The method for producing aromatic polyamide yarn according to the present invention is based on the following formula: -Co-Arl -CO-, -NH-Ar, -N)
- and -CO-Ar, -NH [In the soil formula, Ar11+ to r2+Δr are each divalent':
y5 frost group group group group, 'JRArl y in the polymer
Ar2, and at least about 90 total of A, r3
Mol% is linear coordination. ] An anisotropic dope prepared by dissolving a polymer consisting of 98% carbon dioxide in a mixture of concentrated sulfur, acid, chlorosulfuric acid, fluorosulfuric acid, and acid-containing straw is extruded into the non-coagulated layer, and then the coagulated layer is formed. , and then the pieces of acid chlorine (hereinafter T, abbreviated as "WJ") in the coagulated thread and polymer weight g (hereinafter, abbreviated as "Wpl") in the system were Coagulated thread 1.0
~． It is characterized by applying and removing tension of s, Or/d. , under the sales conditions specified in the method of the present invention,
High Young's modulus without reducing tensile modulus! The details of the mechanism by which fibers are obtained are not clear, and it is difficult to escape from the estimated ft, but the destruction of the fiber structure that occurs at the same time as the orientation of the crystal part caused by the pulling tension remains as a solvent. I don't think this is due to the sulfuric acid being added to the sulfuric acid.

Therefore, in the method of the present invention, the coagulated fibers pulled out from the coagulation bath have an acid weight and a Bo11mer weight ratio Ws7 Liaop of the fibers, which are one index of the coagulation state, in the range of 01 to 08,
1.0 to 4. Q? It is necessary to apply and remove the tension of /d.

In a coagulated yarn with a WsZWp ratio of less than 0.1, it is necessary to apply a large tension that may cause structural destruction in order to increase the Young's modulus, resulting in fiber shedding and a significant decrease in tensile strength. On the other hand, coagulated threads with a WsZWp ratio of more than 08 have a coagulated thread of 1, and the tension applied due to incomplete fiber formation is 1.0 to 4.
．． (before 0r/d), even if it is 4, it is not a fiber with a high Young's modulus, and also causes a decrease in tensile strength.

Even if the WsZWp ratio is in the range of 0.1 to 0.8, the applied tension is 1. If the foam is less than O1i'/d, the Young's modulus cannot be improved sufficiently, and 4. If Or/d is lowered, a high Young's modulus can be obtained, but the elasticity of the υ-th j will be greatly reduced, making it impossible to achieve the desired purpose.

In the present invention, aromatic polyamide polymer 11
The following single (λγ -NH-Ar1-NH-(1), -Co-Ar2-CO
-(II) and -Co-A, r3-NH, -(II
I) [in the above formula 1. Qf, positions (1) and (11) are present in substantially equimolar amounts in the carbolimer, and Ar1.
Ar2, A, and r31: each represent a divalent aromatic group. In addition, at least 90 mol% of all the groups Arl, Ar2, and Ar3 in the polymer are those in which amide groups are bonded coaxially or in parallel in the opposite direction of the aromatic group, and the chain is linearly connected as a whole (directly connected). (referred to as a heavy aromatic polyamide)].

Divalent aromatic group, Ar1, Ar2M and Ar3, specific K IrJ1 paraphenylene, J, 4'-biphenylene, 1,4-naphthylene, 1,5-naphthylene, 2,
6-naphthylene, 2,5-pyridylene h, and
l et al., halogen, lower alkyl, nitro, methogin,
One, two or more substitutions may be made with an inert group such as a cyan group. Ar1, Ar2 and Ar3 are all 2
PJx may be more than one species, or even if they are the same
It's okay to stay.

The polymer of the present invention is produced from diamine, dicarboxylic acid, and aminocarboxylic acid corresponding to each unit by a conventionally known method. Specifically, a method in which a carboxylic group group is converted into Kl such as an acid noride, an acid imidazolide, an ester, etc. and then reacted with an amine group, or a method in which a diamine is reacted with an iso-
A method is used in which the dicarboxylic acid is induced into an ananate and reacted with a dicarboxylic acid. As for the polymerization method, so-called low-humidity solution polymerization, interfacial polymerization, melt polymerization, in-phase polymerization, etc. may be used, and the present invention is not limited to this method. With ten to give! h'wμP It's one thing that is voiced.

In general, it is preferable to use a polymer with a high degree of polymerization in order to achieve a low yield yQ and a high Young's modulus. Specifically, for fiber braid, the intrinsic viscosity 1 measured under the condition of Δ1:1 constant φ determined by Y' is at least 5.
It's funny that it's 0. From θ size 5 x d1/J
) Ritomo is 55. In addition, it is preferable as a fiber because it causes a decrease in the degree of polymerization of the reamer during the -MF acid dissolution and the Ilil bobbin thread process of the spinning solution. f17 Intrinsic viscosity f (f, specifically ↑, melt j
117 (Although it varies depending on the wet store f1 and stay 1! Zr in the step and subsequent steps, it is recommended to use a polymer with an intrinsic viscosity at least 01 to 05 higher. Dandruff is not particularly limited, or it is desirable that the viscosity of the dope is about 10 or less.In carrying out the present invention, it is necessary to use these polymers as a dope. Sulfuric acid, however, consists essentially of a mixture of sulfuric acid, chlorosulfuric acid, fluorosulfuric acid, and the like at a concentration of at least 98%.Sulfuric acids include SO, in excess; ■1.Fuming sulfuric acid may be used, but excessive So.

If 111I is present, the inherent viscosity of the polymer decreases during dope storage.
ij: It is desirable to maintain the required minimum β[ψ and to perform the spinning in a short period of time while maintaining the dissolution humidity. For example, additives such as hydrofluoric acid, halomonoalkylsulfonic acid, and halogenated aromatic sulfonic acid may be mixed into the strained solvent. Also, antioxidants, ultraviolet absorbers, dyes, and flame retardants may be added to the dope.

Furthermore, a hoe having a high degree of strength and a high modulus useful as a high-performance plastic reinforcing agent, which is a feature of the present invention! I
In order to produce I', the concentration of polymer in the dope must be at least 14% by weight, preferably 17% or more, but specifically, the intrinsic viscosity and type of the polymer used must be , should be determined by the concentration and type of melting.

The aromatic polyamide dope used in the spinning method of the present invention is usually solid at room temperature, and at temperatures above the melting humidity, the polymer exists in a nematic liquid crystal state. When I observed and guessed it, 17F
4: 4g gloss is observed.

Pi18 brazed dope is spun using an air discharge wet spinning method using a drawing material and reversing an orifice. However, in the present invention, the air discharge wet spinning method refers to the dope being passed through an orifice and then spun in one short engraving process. A general term for a power spinning method in which an inert fluid layer, such as a gaseous medium or toluene or heptane, is compressed and then extruded into a coagulating liquid6, that is, in the spinning method of the present invention, the spinneret surface , rf coagulation liquid et al.
The thickness of the fluid layer is usually about 0.
The length is preferably 1 to 10 m, preferably 103 to 2 m. The fluid layer is not limited to stiffness, but
It is determined by factors such as the speed of dope discharge from the orifice, the draft of the spinning, and the possibility of reducing the chance of filament fusion.

Ws/Wp of coagulated thread is 0. In order to obtain the pre-concentration of J-0, 8, there is a method of changing the depth of the coagulation bath or thread removal speed to change the contact time between the dope and the coagulation bath, or changing the coagulation liquid composition and coagulation liquid. A method of changing the diffusion rate of the acid in the dope by changing the temperature is adopted.

Which one? However, before applying the power of the present invention to exert the effects of the present invention, it is necessary to use the method described in detail 1 below to apply X-mari/Wp! II is a power of 1.

In general, the shape of the coagulation bath r1 can be either vertical or horizontal t7, and as an example of a vertical type, a cup can also be used. In the bath, the coagulating liquid may be allowed to flow, especially preferably flowing in the same direction as the fibers, as this may cause unnecessary turbulence in the fibers.
Sulfuric acid aqueous solutions ranging from water to 70% concentration are used, but NH
4oH, CaCρ,.

K, COs, NaC, # It may be an aqueous solution of a salt such as Kasa or -1: straw imitation, or an aqueous solution of a suitable organic solvent such as methanol, ethanol, or ethylene glycol. It is not something that will be done.

The coagulating liquid is generally kept at a temperature of 15°C or lower, preferably 10°C or lower.

A method for imparting tension to the coagulated thread is, for example, a tension bar device in which one or more conventional pars are swirled in a zigzag pattern of 1 m between the coagulation bath and a take-off roll at an angle to the take-off direction of the coagulated thread. , a general method is used, such as applying an appropriate weight to a pair of rolls whose speed increases or to the fiber between a pair of rolls, but this method does not particularly satisfy βR.

Check the tension! isu7. Temperature and atmosphere at 17;'rK
Flir PJ? For example, 1o
It can be done by stretching in saturated water vapor at 00°C or higher, but in general, in order not to reduce the tensile strength and intrinsic viscosity of the u1 fiber, it is necessary to draw the fiber at room temperature It is carried out in one body.

The tensioned fibers are then washed with water and converted into a furnace. Washing with water will reduce the intrinsic viscosity, tensile strength, and Young's modulus during the drying process; in order to make the scale less sticky, the residual melt should be at least 1% or less based on the dry weight of the fiber, preferably 2nOppm.
It is preferable to do the following. There are no particular limitations on the method of washing with water, but for example, after the drawn fibers are once wound up on a bobbin, they are immersed in water and washed on the bobbin. In addition, it is preferable to wash by hand with a net, but neutralization with an alkali may be used in combination to reduce residual dissolved n-nephew in the iron.

The washed fibers are then dried and polished. Drying is not particularly limited (c), and is usually carried out on rolls or on a net conveyor at a temperature of about 50 to 300°C, and at a temperature of 80 to 300°C.
200°C is more convenient.

When producing aromatic polyamide synthetic fibers by the method of the present invention, if necessary, it is necessary to add an oil agent or an aphrodisiac to the fibers in the heating process, or to untangle the fibers by twisting or air jetting. It is also possible to give, and it is suitable for ten to increase productivity.

According to the method of the present invention, fibers having a high Young's modulus can be easily obtained without high-temperature heat treatment, and therefore costs can be significantly reduced. In addition, the fiber d1 produced by the method of the present invention maintains tensile strength and specific utilization, has excellent uniformity, and has at least 8 (
It has a Young's modulus of 10 f/d or more and a tensile strength of 21 f/d or more, and also exhibits good heat resistance. In addition, since the j-type yarn (t) is reduced to allow high young rods to be pierced without heat treatment at high temperatures, it is possible to significantly reduce costs.

Applications of the fibers produced by the method of the present invention include, but are not limited to, the use of fibers in the industrial materials field, particularly as high-performance plastic reinforcing materials, due to their invasive strength, Young's modulus, and heat resistance. It is useful.

A method for measuring the physical properties of the coagulated thread of the present invention will be described below.

<Intrinsic viscosity measurement> Concentration C = 0.5 in 985% concentrated sulfuric acid? /de
The viscosity of the solution containing the polymer fibers was measured at 30°C by the 'po method, and the intrinsic viscosity) θ (ηj
nh ) is calculated.

in ηret ηlnh = - <Oil method for experimental elongation characteristics of fibers> A load-extension curve was drawn at 20° C. and 65% RH using a constant speed elongation tensile tester, and the results were determined by writhing.

<Method for measuring the Ws/wp ratio of tethered yarn>
++ After winding up the fibers and making them into skeins, use a centrifuge to remove liquid for 1 minute under 6+0 (H1 rpm), perform neutralization titration with 01N NaOH, and measure the acid weight Wg. After titration. After washing and drying the fibers, the weight Wp was measured, and Ws/
Wp (7)) Find l1, n4. The present invention will be clearly explained with seven examples. In each example, composition ratios are based on weight % unless otherwise specified.

Reference Example A PPTA polymer was obtained using a low temperature solution polymerization method.

In a matching apparatus shown in Public Employment No. 53-43986, 70 parts of calcium chloride was dissolved in 1 part of N-methylpyrrolidone I, and then 48.6 parts of paraphenylene diamine was dissolved. After cooling to 8° C., 91.4 parts of terephthalic acid dichloride was added at once in powder form.

After a few minutes, the polymerization reaction product solidified into a cheese-like shape (7), so the polymerization reaction product was discharged from the polymerization reactor P according to the method v3 described in Japanese Patent Publication No. 53-43986, and was immediately transferred to a twin-screw closed kneader. The polymerization reaction product was then pulverized in the same kneader.Then, the pulverized product was transferred to a Henschel mixer, and 1% water was further pulverized. It was washed several times in dry water and dried in a hot oven at 110°C.

95 parts of a pale yellow PPTA polymer of hard and viscous 5 was obtained.

In addition, the polymer (c) with a reduced intrinsic viscosity can be easily prepared by changing the ratio between N-methylpyrrolidone and the monomer (para-phenylenediamine and terephthalic acid dichloride) and the ratio between the monomers. Obtainable.

According to Example 1 and the example, "1 built PI with 56 unique clay dams"'
The TA polymer was placed in 995% concentrated direct acid at 70°C so that the polymer concentration was 18%. it f
Dissolved. The melting process is carried out under vacuum, and after melting, it is left to stand still for 2 hours! The dope was anisotropic. Dope is passed through gear pump-cyp3
0゜mesh stainless steel gold λ, 8 layers of i feathers, 5 layers of stainless steel gold 8.1:j, 2 tons of winding, 7 sigiyandoru filter to perform F vortex, O, T 16mmφ orifice 100 Spun with gold [] from 5-open air core ', ', iifi, then concentrated N 5%, temperature 2
It was extruded into a sulfuric acid coagulation solution at ℃. The coagulated thread taken out from the shoulder bath through the direction change guide has a Ws/Wp ratio of 0.4.
It was 2.

Place five shuttles in the atmosphere between a pair of rolls】6゜2
After applying tensions of 0 and 2.8 f/d, it was wound up onto a bobbin, washed with running water overnight, and dried at 110° C. for 2 hours. The first fiber thus obtained had a high Young's modulus as shown in Table 1.

As a comparative example, we will show the physical properties of a fiber that was rolled up on a hobbin, washed with water, rolled and encouraged without applying any tension.
The following is shown υ7 Example 2 Hardness 1 viscosity) O65 PPT manufactured by 1"J in contrast to the reference example
Polymer A was placed in 995% concentrated sulfuric acid so that the polymer concentration was 20% 1C-. this dope order 7
(+, spinning yarn with 06 diameter 500 (1, l [from 1 gold, 0,5 r++m (7') '!,' between sj: Q, dark bar: 40%, i, X #' - Pressed in a sulfuric acid aqueous solution at -5℃ and poured out.)! Pulled out from the same bath.
The No. 16 coagulated thread had a WII/■/p of 0.74. The fibers were placed in the atmosphere between a pair of rolls at 1.2,1
．． 5 and 2. After applying a tension of flf/d, the fibers were shaken off onto a net conveyor, and then dried on a net conveyor to obtain fibers with a high Young's modulus as shown in Table 2.

Example 3: 50 mol% of terephthalic acid dichloride, 40 mol% of phenylenediamine, and 4,4'-diaminodiphenyl dichloride I (1 mol% as a reference example). K F is a polymer manufactured by I; (995% of polymer with
The polymer was dissolved in sulfuric acid so that the concentration of the polymer was 2 f1%.The dope was extruded into water at a temperature of 2°C in the same manner as in Example 1, and then pulled out from the coagulation bath. The fl coagulated yarn has a Wt+/Wp of 0.12. The fibers were washed with water and dried in the same manner as in Example 1 to obtain fibers having a high Young's modulus as shown in Table 3.

s, bottom margin

Claims (1)

[Claims] 1. Units represented by the following formulas -CO-Arl-CO-, -NH-Ar2-NH- and -CO-Ar, , -NH- [In the above formula, Ar7. Ar2 and Ar3 are each 2
represents a valent aromatic group in the polymer, Ar1. A
At least about 90 mol% i3 of the total amount of r2 and Ar3
i7j is easy to distribute. ] An r-oriented dope prepared by dissolving a polymer consisting of 988 weight or more of concentrated sulfuric acid, chlorosulfuric acid, fluorosilicic acid, or a mixture thereof, is extruded into a non-coagulated layer, and the coagulated layer is passed through, Next, the ratio of 9 weight (hereinafter abbreviated as "W8") in the coagulated thread to the polymer mold part (hereinafter abbreviated as "Wp") in the system becomes 01, and the coagulated thread becomes 08. 1
．． A method for producing aromatic polyamide fibers, which comprises applying and removing a tension of 0 to 4.0 f/d by +1. 2. A method for producing poly-P-phenylene terephthalamide having an intrinsic viscosity of at least 5.1. 3. The manufacturing method according to claim 1, characterized in that a p-tropic dope having a polymer concentration of at least 14 is used.