JPS5943114A - Poly(p-phenylene terephthalamide) fiber - Google Patents

Abstract

PURPOSE:To provide the titled fiber having high strength, uniform strength and Young's modulus, excellent homogeneity and little fluffs, composed of a number of filaments having uniform sectional area and specific density, crystal orientation angle and logarithmic viscosity, and useful as industrial fiber, etc. CONSTITUTION:Poly(p-phenylene terephthalamide) is dissolved in sulfuric acid, and deaerated under reduced pressure. The obtained dope is extruded through a spinneret having a number of circular nozzles, transferred in air, and introduced into an aqueous solution of sulfuric acid to obtain the objective fiber composed of >=50 filaments having a density of >=1.41g/cc, a crystal orientation angle of <=30 deg.C, and a logarithmic viscosity of >=3.0dl/g measured in 98wt% sulfuric acid at a concentration of 0.5g/dl at 25 deg.C. When the sectional areas of the filament are measured at >=50 points of arbitrary filaments or in a filament with intervals of >=1mm., the value obtained by dividing the mean square of the measure values with the mean of the measured values is <=0.14.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to an improved poly(p-phenylene teretalamide) (hereinafter sometimes abbreviated as PPTA) +1 fiber. More specifically, the present invention relates to a Pi)TA woven fiber having improved strength, small variations in strength and Young's modulus, and excellent homogeneity.

``It has been predicted for a long time that fibers with excellent tensile properties would be prepared from PPTA, which is a tetrafunctional polymer, and in fact, it has been predicted that fibers with excellent tensile properties could be prepared from PPTA, which is a tetrafunctional polymer. (Japanese Unexamined Patent Publication No. 47-39458) et al. have disclosed a method of placing high-strength edge sheaths.The PPTA fiber cords 61 produced by these methods have large variations in strength, Young's modulus, etc., and are suitable for use in ridges made of There is a problem in terms of reliability.This is caused by, for example, half-cut single filament.
Among the fibers (multifilaments) made from 11 fibers, the (average value) of the strength of the vinegar threads is approximately 20 qb greater than that of the fibers (multifilaments)! This is suggested by the description in Japanese Patent Application Laid-Open No. 47-39458.

According to the inventors' laboratory I], 1.1. During the production of precepts -
Due to excessive tension and temporal or spatial fluctuations during extrusion, elongation), coagulation, water washing, drying, heat treatment, etc., and abnormally large non-Newtonian properties of the dope,
10 elongation) ゛“0 spin D #”J 7 s: L tsu 0-
The fluctuation of 1 noi is the fluctuation of the cross-sectional area of the fiber (multifilament) in the yarn length direction and between the single yarns.
□This is the main reason for the imbalance of the tensile properties of the strong maragasa.

It was thought that this was the result of ki. In fact, commercially available PPTA fibers such as Kevlar and Kevlar 49, especially the latter, have a considerably large variation in cross-sectional area.

The present inventors have demonstrated that the tension during the production of PPT Affl fibers is low.
11 Through a combination of reduced density, spinning, IJ 742 3° arrangement, etc., fibers with a uniform cross-sectional area (multifilament), which has not been seen in conventional PP'l'A i)j% fibers, have been created.
They succeeded in producing a prototype of 1fIi fiber, and discovered that the variation in tensile properties such as elongation and Young's modulus was smaller than expected, and the average strength value was also increased by 2. Furthermore, they discovered that it has an unexpected feature of having few fuzz (fibril) defects, leading to the completion of the present invention.

That is, in the present invention, the density is 1.41 Vcc or more,
It has a crystal orientation angle of 30° or less and is 0.0% in 98% sulfuric acid at 25°C. ．． The logarithmic viscosity measured at the concentration of j597di is 3. , o 4 vg or more of poly(p-phenylene terephthalamide) substantially υ, 50 wood or more'';
41'ih', r; It is a fiber composed of fibers, and is straddled by beating different arbitrary single yarns in the fiber/and one within the same single yarn.
Poly(p-phenylene) whose value obtained by dividing the unbiased variance of the measured values by the average value of the measured values is 0614 or less when the single yarn cross-sectional area is measured at 50 or more points at arbitrary intervals of terephthalamide) fibers, all of which are provided.

The fibers of the present invention consist essentially of PPTA. Here, the meaning of "substantially" means that polymers other than PPTA (for example, poly(m-phenylene terephthalamide), poly(P-phenylene isophthalamide), ),'p
ie IJ"' (rn-phenylene isophthalamide)
, poly(polyglutylene ethylenephthalamide), aliphatic polyamide, alicyclic polyamide, polyester, polyimide, 73? polyurethane, polyurea, etc.), PPTA is blended with other repeating units (e.g., nuclear-substituted p-phenylene units, nuclear-substituted or unsubstituted biphenylene units, o-phenylene units, m-phenylene units). , methylene units, pyridyref units, bonding units such as emether, urethane, urea, ether, thioether, etc.) are copolymerized, and various additives and compounding agents (for example, dyes, anti-aging agents, etc.) are copolymerized. □ indicates that UV absorbers, brighteners, pigments, etc.) are added.

The fibers of the invention should have a density of 419/cc or higher. If the density is less than 1.4197cc, it means that the fiber contains many cracks and voids, has extremely low crystallization, or has an uneven agglomerated structure, resulting in low strength. . Such a low-density 7-layer fiber can be obtained by wet spinning directly from a spinneret into a coagulation bath r4' or by spinning with a very small draft. For strength and knot strength to be at a more desirable level, at least 1.
PP1'A fibers with a density of 4397 ac are preferred.

The density of the PPTA 41 miscellaneous material of the present invention can be measured by a conventional method using toluene and carbon tetrachloride at 25°C using a density pipe.
It should have a crystal orientation angle of 30° or less, as measured by the diffraction peak at 2θ #23° according to the method described in Publication No. 012. This is because PP that does not meet this requirement
This is because TA fibers have low strength and Young's modulus, reducing their value as industrial fibers. Preferably, the fibers have a crystal orientation angle of 25° or less.

The fiber of the present invention comprises 3. Logarithmic viscosity of Od〆g or more (77,
,ゎ; 0.5 i/d in 98 wt% sulfuric acid at 25°C
611] at the density of i). This is because having a high degree of polymerization is one of the necessary conditions for having high strength. Desirably, the PPTA constituting the fiber is 4. It has a logarithmic viscosity of Od679 or more.

The present invention can be applied to fibers made up of 50 or more single yarns, but this is because variations in the cross-sectional area of single yarns are not considered a problem in fibers made up of fewer than 650 single yarns. The upper limit r of the number of single threads in the fiber is not particularly limited to 1. f) The effect of the present invention becomes more pronounced as the number of threads increases; for example, from 500 for tire cords.
When using fibers with a number of 3000 single yarns, the fibers of the present invention are superior to conventional fibers with large variations in cross-sectional area in terms of melting, average strength, elongation, Young's modulus, looseness, number of fuzz, etc. There is a significant difference.

The fiber of the present invention can be used between different arbitrary single yarns in the fiber or/and between one or more arbitrary intervals within the same JM system.
When the cross-sectional area of a single yarn is measured at 50 points or more, the value obtained by dividing the unbiased variance of the measured values by the average value of the measured values is 0.14 or less, and -11-< is 0.10 or less. It is. In other words, these characteristics mean that the fiber of the present invention has a cross-sectional area balance between single yarns, inside the yarn, and in the yarn length direction within the system.
? This means that it is very small. In contrast, conventional PPTA fibers have 11J within and/or between single yarns.
The variation per area is large. For example, double-layered Kevlar (referred to as PPTA fiber, made up of approximately 1000 circular filaments) and Kevlar 49 (PPTA fiber)
The diameter of PTA 4g (referred to as PTA fiber, which is composed of approximately 1000 circular single filaments) was then arbitrarily extracted using an optical microscope.
After measuring the points and adding the unbalanced TKJ bonds to 1 niji, the values obtained by dividing the unbiased variance by the average value are 0.17 and (, ), 28, respectively. The distance between single yarns was measured in the same manner, and the results of 1) were 0.16 and 0.30, respectively. It's moss, Japanese Patent Publication No. 47
Publication No. 39458 Publication I) Ability to manufacture PTA fibers (It can be easily determined that the cross-sectional area of the fibers of the 11 examples has considerable variation. Fiber kL with very little variation in
This is because special notes such as reduction of tension during manufacturing, improvement of spinning orifice arrangement, etc., are required.5
The fiber of the present invention, in which the value obtained by dividing the unbiased variance of the cross-sectional area of the single yarn measured at 0 points or more by the average value of the measured values, is 0.14 or less has an average strength value of 0.14 or less compared to conventional fibers. It has characteristics such as being soft, having small variations in strength and elongation and Young's modulus, and being less likely to generate fuzz (fibrils). Historically, when the fiber U1 of the present invention is twisted to make a cord, U
Il Yuru 4,! ,! It was also found that it has a /F+f color with a high power utilization rate. These characteristics are as described above, and (unbiased variance)/(mean value) is 010.
It becomes more serious in the following cases.

In the present invention, the method d for measuring the cross-sectional area of a single yarn is not particularly limited, and any known method can be applied. For example, a fiber is cut perpendicularly to the yarn length direction by C, and the cross section is yt.
Observation 1 by enlarging with a science microscope '3b'R shade, method of calculating cross-sectional area (can measure variation in cross-section '1t-i f?# between single filaments), When the fibers are present, the side surface of the wound fibers is observed with an optical microscope, the diameter is measured, and the cross-sectional area is determined from this (the variation between single fibers, the variation in the length direction within a single fiber, or both the t-nid) is determined. ), a single fiber is placed in an optical path with a constant cross-sectional area.
A method of calculating the cross-sectional area of a single yarn from the pre-cut that is directly interrupted by the single yarn (mainly, it is possible to measure the wobble of the single yarn in the yarn length direction. Since the average value is measured, in this case it is safe to convert it to the differential value of each point). Measure the cross-sectional area? Make sure that the location is not arbitrary. For example, when not measuring all single yarns, select single yarns at random, and when determining measurement points in the yarn length direction, measure points at equal intervals starting from 1 or 2, or at intervals proportional to the numbers on a random number table. It may be necessary to devise measures such as doing so. When measuring the cross-sectional area within a single yarn in the yarn length direction, it is necessary to use an interval of 1+mn or more. Also,
Regardless of the method used, it is necessary to measure the cross-sectional area at 50 points or more. These measurement conditions are important in improving the reproducibility of results. As long as the above points are observed, the measurement within a single yarn and the measurement between single yarns may be performed in a similar manner.

The fiber of the present invention is not particularly limited in its single yarn thickness (average value), but it is usually 0.1 to 10 deniers. Further, the cross-sectional shape is not particularly limited, but is usually substantially circular.

The fibers of the present invention have structural characteristics such as a high degree of polymerization, high density, and high crystal orientation, as well as small variations in cross-sectional area. is small 1, <,■ Sieve 8 for twisting rod force type when the helical electric type (fubblil) is difficult to reproduce and is undone: It is understood that the fibers of the present invention can be obtained only by adding /j2 to the manufacturing method of PPTΔ fibers. However, the manufacturing method thereof is not limited to the method described below.

Made of fibers) 1, PPT+ is sulfurized, and sulfuric acid is the main ingredient! At least about 15 V in the absence of solvent.

It is necessary to prepare a dissolved doi so that the polymer concentration is . In this case, IPTA i7. J:, as mentioned above, if necessary other r! The tray may be slightly closed, or it may be used in a small fan or blend with other 73 hirimar etc. Also, I) PTA is generally in a doped state and causes a slight decrease in the degree of polymerization, so take this into consideration.) PP and TA preferably have a viscosity of 3.5 J. Will.

For example, P-jiku TA is Tokufuyusho 3, . 5,,-. 1.4,
,,． 39,. The method described in Publication No. 9 can be used.

Prepare the dope. The solvent used for this is ・Sulfuric acid U (#t P2. It is preferable in terms of dissolution and dissolution.Oleum is also good.As for substances that can be mixed with acid,
Examples include chlorosulfuric acid, fluorosulfuric acid, dichloroacetic acid, acetic acid, phosphorus pentoxide, and nitrobenzene.

A fiber spun from a dope with a poly-concentration of about 15 layers is
In general, the density and degree are small, the structure and strength are also small, and it is solid. Concentrations of 1, 3, and 30 often require a little heating.

As the temperature increases, 71' in dope! (The rate of deterioration of the IJ machine will increase), so it is best to expose it to high temperatures for a long time (not preferable = normal) Room: Temperature to 120℃
A range of dopes is used.

What is the dope used in the present invention? Shows iochemical anisotropy.

It may also contain ordinary additives such as antioxidants, ultraviolet stabilizers, etc. .

The dope made in this way is transferred from the spinneret into a non-coagulable fluid and then held at a temperature of less than 3 degrees Celsius, which must be extruded into the same bath with a force of ≦3. It is especially useful for industrial heavy-duty processes to perform de-netification of the dope before it passes through the spinneret.

Saddle cap number 1. , the number of holes, the size of holes 9, and control! However, the distance between the spinneret center of the hole closest to the center of the spinneret surface and the distance of the hole farthest from the center of the spinneret surface is The distance between and the ratio of o, 5 to 1. , O, Niru, Isu, Shiku, must be between 0.65 and 1.0. That is, the holes should be located at the distance from the center of the spinneret surface to the position where i exists. There seem to be two reasons for this harmful request: 1. 1: Because the dope also has optical anisotropy, the non-Newtonian flow characteristics are extremely large, and there is a huge difference in the distance from the center of the entire surface of the spinning yarn. In the case of a single spinning spinneret with holes, there is a difference in the dope discharge between the holes, which is one of the causes of the increase in cross-sectional area between single yarns. Dust, and the other is: The dope flow discharged from the hole near the center of the spinneret surface and that from the outer 4n11 holes are affected by coagulation (solidification rate, tension, direction, and their distribution). ) is different, resulting in an increase in the unevenness of the cross-sectional area between single yarns and within each q single item.

The hole or raccoon dog may be of a so-called irregular shape, but usually a circular one is used.1. Its size is usually o, bla, 7.
A diameter of 0.01.5 mm is used. The linear velocity of the dope that can be deposited and discharged from the spinneret is not particularly limited, and may be determined based on requirements such as productivity and requirements for drafting, which will be described later. It is essential that the dope stream extruded from the spinneret first pass through a non-solidifying fluid. This is because it is difficult to make the draft larger than 1.5 when the spinning material is extruded into a solid coagulation bath without passing a non-coagulating fluid. (Jiwei is
It has a low density, low strength and elongation, and is a carcass. Examples of non-coagulable fluids include gases such as air, nitrogen, nitrogen, argon, and oxygen, and liquids such as toluene and heptane. Due to its economical advantages and ease of use, air is most preferred.

, non-coagulable flow, body thickness is approximately 0.2-50 cm (
Leprosy is appropriate.

The dope 0 stream extruded into the non-coagulable fluid is then (,)
It is necessary to extrude it into the same bath, where it undergoes coagulation.

In the production of the fiber of the second invention (d1), the temperature is preferably about 50°C or less, more preferably 1.
2) at temperatures below 5°C. +1℃, the first crystal of C is also good.
Ill be able to. Use 1' fl (', (47! Solid liquid is water, 11 city ling aqueous solution, caustic soda aqueous 戊戊, Ill'
Fil suggests a water solution of soda.
・(or methanol, ethylene glycol, acetone, etc. of these aqueous solutions 1≦(δ liquid).

A (; ij It < 1 The previous 1 Toro shape is due to the fact that the I polishing force applied to the coagulated threads and materials during doubt solidification is small; From the llijb points such as being immediately in symmetry,! Hemorrhoids 14) 4 1975
-122 (411I in Figure 3 of Publication No. 112-,
It would be preferable to use the f-trough for the so-called p-doo-shaped ζ. When waiting for Vεε ('iJ fixed yarn yarn tension?'
, -r % coagulated thread 2 white I snout was watered 7 times and dry FA / after this, ・or, ・(about 0.5 soybean per vinyl of r-)
) J, preferably below, and the yarn drawn from the coagulation bath, the shallow sulfur iβ in the south, is yje +) mer 1g
A draft of at least 1.5 is applied to the coagulated filament from the coagulation bath. Pull out at speed. Here, the draft is the value obtained by dividing the linear velocity of the coagulated filament when it is drawn out from the coagulation bath by the dope line 94nl-f passing through the spinneret. draft is 1
．． If the fiber is unfinished, the orientation of the PPTA molecular chains is often insufficient, resulting in fiber #1 having low strength and Young's modulus. 1.raft is preferably 2.0 or more.

7. When pulled out from the hard bath, the proboscis must be washed with water. Washing with water is carried out in one stage or two or more stages, and in order to do this efficiently, it may be combined with an alkaline aqueous solution such as Kahii soda.

It is preferable to extract and store as much of the solvent as possible by washing with water. For example, when using Type 161 acid as the solvent, the
It is preferable that the residual amount is as follows. Washing with water is preferably carried out under a tension of about 1 or less per 1/L of the fibers after drying, and from this point of view, the coagulated threads are deposited on the net. The method of pouring water on the water is preferable, and among these methods, Japanese Patent Application Laid-Open No. 55-122011 and Japanese Patent Application Laid-open No. 5
5-1.2 2012-Disclosed in the same publication (f4〒Under the specified conditions, the net 10 is 71 years old, steam treated, dried,・■
It is most preferable to increase the dimensional stability of the fibers and improve fatigue resistance.

After being washed with water, the fibers are treated with oil, etc. if necessary, (1) dried, (2) dried, treated with water, and (() washed with water. The yarn is then heat-treated and made into a finished product using one of the following methods.During this process, steam treatment, etc., may be added if necessary.

It is done using the well-known technique i+ti. Through h(
, preferably above 1-11°C, for a period of time such that the amount of water in the fibers is less than 10,000 degrees P-cent/F- respectively.

- The method is free, for example, depositing it on a net, l? It can be done by simply attaching it to a bottle or wire, or by running it on a heated roll.

2nd stage or more
It may be heated to 1-1' at a different temperature or in the same or different manner.

Strictly speaking, drying and heat treatment cannot be used to tighten the fibers, but in the present invention, the act of applying heat under no tension or under (lower tension) is used for the sole purpose of reducing moisture in the fibers. :iHI: The act of applying heat to a fiber under tension for the purpose of significantly changing the elongation r!s'h- and Young's modulus of the fiber is called hot sawing. 1 inch long (・ has a high elongation of 11 to -, and is suitable for uses such as tire cords. On the other hand, after drying at 17, it can be kneaded, or it can be washed with water without drying and heat treated to i0 contact. The fiber has a high Young's modulus and is suitable for use in plastics. Heat treatment must be performed at 200 to 550°C under a tension of at least 0.2 g/d. This is because, if these conditions are met, P PTA -J='1 fibers with an extremely large Young's modulus can be produced by heat treatment, making them useful for reinforcing plastics. Ameshuke 250-45 (H:) Appropriate heat treatment time is 1, depending on the temperature, but generally +'Q is applied between 0.1 seconds and 10 minutes.Heat 9 (1 fl
The atmosphere in which this is carried out may be air, but in most cases it is inert nitrogen or argon.

The fiber #fi of the present invention is a conventional PPTA 18! with high strength and high Young's modulus. ll! In addition to the fiber's l period, it has 11 strong elongation, small variation in yafugu rate, few fuzz defects, 10 is added, and e-M is 7 years old.
It also has characteristics such as a high strength utilization rate (when ab is loosely twisted), and by making use of these properties, it can be used as a reinforcing material for rubber such as □Diaco P1□ for various belts, □as a supplement for Delastitta.
It is useful as an H material. *MV of the present invention is these-
1? When used for reinforcing aluminum or plastics, it is usually used in the form of a multifilament, and in this case, the above characteristics are maximized, but the fibers of the present invention are limited to each of them. Ropes, woven fabrics and plastics, metals, cement, etc., in the form of monofilaments, roving yarns, staples, chopped strands, etc.
It can also be used as a reinforcing material for ceramics, etc., or as a rug.

Example 1 and Comparative Example 1 PPTA having a logarithmic viscosity of 5.8 dl19 was obtained according to the reference example of JP-A-55-122012.

PPTA 9'9. '6 Polymer concentration in sulfuric acid is 1
Dissolve at 75°C to a concentration of 8% by weight, and defoam under reduced pressure for about 2 hours. While filtering the dope maintained at 25 to 80°C, t.0. □0□65-diameter, circular, 200 pores, extruded through a spinneret, about 5 mm.
After running □ in the air, it was extruded into a 7°C sulfuric acid aqueous solution of 51%.

The following two types of spinnerets were used.

A: It has a spinneret surface with a diameter of 36 mm, and 47 pieces are placed on a pitch circle with a diameter of 32.0' from the center of the spinneret surface, 27.
41 pieces on a pitch circle with a diameter of 8ynm, 23.6m+a
35 pieces on a pitch circle with a diameter of , 29 pieces on a pitch circle with a diameter of 19.4 m, 15. 22 pieces on a pitch circle with a diameter of '2+mn, 11. There are 200 pores in total, 16 on a pitch circle with a diameter of 1.5 mm and 10 on a pitch circle with a diameter of 6.8 -, with the pores closest to the center of the spinneret surface. The ratio of the distance from the center to that of the pore farthest from the center of the entire surface of the spinneret is 0.21.
.

B: It has a spinneret surface with a diameter of 45, and there are 59 pieces on a pitch circle with a diameter of 41.0-36.8 from the center of the spinneret surface.
53, (m, 32Brr
47 pieces on a pitch circle of diameter m and 28.41+I!
A total of 200 pores, 41 of which are located on a pitch circle with a diameter of The ratio of that to that is 0.69.

The coagulation bath, water washing, and drying steps are described in Japanese Patent Application Laid-Open No. 55-1220.
The process was carried out using the apparatus and method conditions of Example 1 of Publication No. 12 (that is, a steam treatment step was added between the water washing step and the drying step) to obtain ppTA fibers.

Table 1 lists the varying conditions and properties of the obtained fibers.
Shown below. The strength, elongation, and Young's modulus of the fibers are the values measured for 200 single-filament multifilaments at n=10, and the cross-sectional area of the single threads was measured using an optical microscope (400x magnification) because they have a circular cross section. The diameter of the single yarn was measured, and the cross-sectional area was calculated from this result. At this time, the variation in cross-sectional area between single yarns is determined by 1 randomly extracted from 200 single yarns.
Measurements were made for 00 single yarns, and the variation in cross-sectional area within the single yarn was measured using 1. '5wn5mm
ioo point was measured.

The fibers of the present invention with small variations in single yarn cross-sectional area (Example 1-1 and Example 1-2) are different from the fibers with large variations in single yarn cross-sectional area (Comparative Example 1-1 and Comparative Example [-2) compared to,
The average strength and Young's modulus are large, and the variation in strength and elongation and Young's modulus is small.

J Go 11., Kashiro Comparative Example 2 The process up to coagulation was carried out by the method and conditions of Comparative Example 1-2, and the washing and drying were carried out on a rotating roller.

To the obtained fiber P&! 2, density], 4311/mm, degree of crystal orientation 20', (unbiased dispersion)/(average value) of tri yarn cross-sectional area I (same as the definition in Table 1) is 0.26, which is the cross-sectional area between single yarns. The wobble was extremely large. The strength of this fiber (multifilament) measured in the same manner as in Example 1 was an average value of 19.8.9/d, an unbiased dispersion of 4° Og/d,
The strength properties of the fibers of Example 1-2 were inferior to those of Comparative Example 1-2 as well as the fibers of Example 1-2.

Example 2 and Comparative Example 3 The fibers obtained in Example 1-2 and Comparative Example 1-2 were heated at 350°C.
A tension treatment was performed for approximately 1.0 seconds. Table 2 shows the physical properties of the fibers after heat treatment. Example 2 is a fiber of the present invention, and Comparative Example 3 is a fiber other than the present invention.

Tsu,] 7 margins 79-

Claims (1)

[Claims] 1. Density is l, 41 jj/cc or more, 30°
If the crystal orientation angle is as follows,
, 597"de) The logarithmic viscosity measured at 3fJ degrees is 3.
Practically, from poly(1)-phenylene teretalamide) which is less than or equal to 7', 1. "It is a fiber composed of 50 or more vinegar threads), and there is also a difference between the single threads of different numbers in the fiber."/And one or more threads within the same thread. Between the intervals [1], the concave area of the single yarn is 50
A poly(p-phenylene prephthalamide) fiber AfG which, when measured, has a value of 014 or less, which is obtained by dividing the unbiased variance of the measured values by the average value of the measured values.