JPS58132109A - Polyamide fiber with high strength - Google Patents

Abstract

PURPOSE:Polyamide fiber in which the relative viscosity of fiber itself, the optical birefringence in fiber cross section, the optical birefringence of fiber and the relationship between strength and elongation at break are in specific ranges, thus showing high strength and high fatigue resistance as a rubber-reinforcing material. CONSTITUTION:Melt spinning is carried out using a polyamide with a relative viscosity of over 3.5 such as polycaprolactam to give polyamide fiber having a relative viscosity of fiber itsefl exceeding 3.5 (measured at 20 deg.C using a solution of 10mg/ml polyamide concentration in 96% sulfuric acid), an optical birefringence in the fiber cross secion satisfying the equation: DELTAnA-DELTAnB>=0.5X10<-3> (DELTAnA is the optical birefringence at the position where r/R is 0.9; DELTAnB is the optical birefringence at the position where r/R is 0.0; R is fiber radius on the cross section; r is the distance from the center axis on the cross section), a fiber optical birefringence DELTAn of more than 50X10<-3> and satisfying the relationship of[strength at break (g/d)X elongation at break (%)]<-1/2>>=46.0.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved polyamide fiber 111%, and more particularly, to a polyamide fiber having high strength and excellent fatigue resistance particularly for reinforcing rubber.

The polyamide that is the raw material for the material intended in the present invention is 20″C
% 9611 concentrated sulfuric acid bath solution at an electrolyte concentration of 10 m/Wd, the relative viscosity is at least 8.6 or more, preferably 4.0 or more, such as l recablock tam,
Polyhexamethylene Vamide, l-hexamethylene sepacamide, copolymers of these polyamides and 1
．． There are 9 polyamides etc. based on 4-V chloromethane bis(methylamine) and O-condensed aliphatic dicarboxylic acid.

These polyamide materials are manufactured using melt spinning technology.
It will be embroidered. As a result of intensive research on the relative viscosity and physical properties of these polyamides, the present inventors discovered that the present invention Kjll
Send it.

When L-lyamide with a relative viscosity of less than 8.5 is refined using the usual spinning technique, the birefringence distribution within the fiber cross section is very small, and the birefringence between the outermost layer and the innermost layer is very small. The roof is
# Lutondo is extremely negligible, and the cutting strength is also high 4
Just know that tOg/dL is low.

On the other hand, for those with a relative viscosity of 8] or more, preferably 40 or more, it is possible to produce 11 m thick fibers by ordinary spinning technology, as described in detail below (as specified in the present invention). However, looking at the distribution of birefringence within the fiber cross section of the fiber obtained, the birefringence increases from the outer layer of 1 m + 1111 to the inner layer. The rate is small 1K (but the table below shows ΔIIA-ΔnBlG, 6Ki0-" (1)
m, and the refractive index Δn is 50 x 1 G-
If it is 3 or more, it will be cut off! ! IM, nodularity, and toughness [i.e. cut #? It was discovered that the strength ffX (breaking elongation) ``A'' was significantly improved, leading to the present invention. Polyamide is a long-known polymer that
n. Polyamide aim is widely used as a material for clothing and industrial use, and one of its major uses is as a rubber reinforcing material mainly for tire cords. Methods for manufacturing such fine polyamides for rubber reinforcement include a multi-stage method (Japanese Patent Publication No. 8M-51189), and a method using a polymer with a high degree of polymerization (Japanese Patent Publication No. 45-1!16).
No. 71) etc. have been proposed. If such a method is adopted, the strength of the polyamide delicate itself or when used as a rubber reinforcing material will be increased! Although the strength and degree of loss during wet temperature vulcanization are improved to some extent, the elongation is conversely reduced, so KI toughness is hardly improved, which is the condition required for rubber bonding materials for tire cords, etc. *M > 9.54g/
d cutting fltr*N (g/d) x (cutting elongation @] K44 @
, 0=what! ) is the required characteristic? t1 nine boreal fibers are difficult to obtain, so IIM obtained by the method
It must be said that the effect of using 49 rubber to improve the strength of #I4# bodies (tires, etc.) was insufficient.

Poly again! - Japanese Patent Publication No. 10888, No. 10888. Tokuko Showa 61-161! J1, special public service No. 48-119869
The Mk stop is proposed. With these methods,
The upper limit of the relative viscosity (IV) during yarn spinning is specified. For example, RV in the case of polycarbonate block tam embroidery is 80 to 44.4 in Japanese Patent Publication No. 48-Igosa, and IO Publication No. 51-2628. So 8.82~4.01. Tokuko Showa 4
8-JI9!19 stipulates that it is in the range of 8.00-450. However, when considering a method for increasing the strength of polyamide by going back to the basic principle, it is difficult to imagine that the strength will deteriorate due to the relative viscosity Rv being too high, that is, the molecular weight is too high. This is because as the molecular weight increases, there is a strong possibility that the number of I4 molecules will increase.On the other hand, currently, III value polyamide AUG with RV of 4.0 or more
An example of yarn spinning is #1, which is very pure, but this m
However, when the RV is 40 or more, the polymer's R resistance and elongational viscosity become extremely high, making stable yarn production extremely difficult.
) can be thought of as rounding, which makes it impossible to dice.

However, the inventors conducted extensive research and found that RV
〉8.5 polyamide, for example, by setting conditions that satisfy the Queen's formula: % formula %, it is known that a sufficient stretching ratio can be obtained in the hot-draw process. That is, the present inventors prepared a polyamide having a relative viscosity of ffRV>8.5 using the above formulas 13) to fε) IIIJi! The fibers must be spun in i, and further subjected to geothermal treatment, satisfying formula 1), I tension [cutting strength x (cutting elongation -) A] is 46.0 or more), and RV ≧8.6, high strength, high nodule ga
We provide polyamide fibers with new me structural properties, which are not found in conventional polyamide fibers, and which have new me structural properties.
It is impossible to make the iam degree, and using the iiamv* rimmer, the conventional boria cut fiber mK has a phase refractive index distribution in the cross section of nine, which is not seen in the conventional boria cut fiber mK. It is characterized by a long fine structure due to scattering, which is longer than that of ordinary meliamide. In particular, J[11 properties such as J[11] can be achieved by using a polyamide mainly consisting of polycaproamide or I-lyequinamethyleneadipamide. 4th place ILC is demonstrated. Among them, polyamide containing 75 mtl1 or more of 4-mericade-a-amide is most suitable. Relative viscosity of Tobo V amide [R
1l-1 like this at an elongational viscosity level of 8.6
It is difficult to create a refracting distribution within 1r, but for the purpose of six, V must be 8.5 or more, preferably 4.
．． Zero or more - must be used. l! In addition, when the 1jjji length phase determined by small-angle X-ray scattering is 100 Å or more, the high-strength properties are significantly improved. Also monofilament DAi
When the vv bell is 60d or less, (the structure in which 181 is added to formula 11 is created), the binding wJ bond is also high.Also, the influence of the birefringence Δn of the undrawn yarn on the total drawing ratio is In order to ensure a very large total drawing ratio of 460 times or more, it is preferable to set the coefficient of undrawn yarn to 0.017 or less.
h, (However, undrawn yarn ΔU is 80°C, 801iRH
・This is the measurement scale after the Lffhr disturbance). The polyamide fiber with the unique rut structure according to the present invention has a cutting strength of 11.0 g/d or more and a knot bond of 8.0 g/d or more, which is difficult to achieve with conventional technology! 4 that satisfies the characteristics
So, does this kind of cutting strength improvement effect affect the relative viscosity?
I & (Stretching a polymer with a high average molecular weight) is considered to be the key to increasing the number of I4 molecules compared to those with normal molecular weight. The effect is that the distribution of birefringence within the cross section is better in the outer layer than in the inner layer.

Birefringence - Rounding %amK with a tendency to Isa
@ζshi' is added and is considered to be the 99th number. Qayness of the polyamide fiber according to the present invention, that is, cutting! llIM×〔
The reason why the breaking elongation No. 3 is high is that by increasing the molecular weight, IM strength can be achieved without causing a decrease in elongation due to non-layered stretching. That is, the Km for producing the polyamide fiber of the present invention is Q/D 498$Ig/see -d
Since it is +, JII sets the spinning conditions to ensure a good harvest. If this condition is missing, the polymer discharge behavior at the nozzle orifice outlet in spinning # will be unsteady), and the spun yarn will break.
With t%A, there is a danger that the drawn yarn will break frequently, and even if it is drawn, it will not be possible to obtain a high-strength yarn.

D”Vv/Q≦118eIL/g
The spinning conditions that satisfy the requirement i41 are set. If the requirements for yarn are lacking, the spinning tension will be high, the running of the spun yarn will be unstable, and yarn breakage will occur frequently. In addition, even if the yarn is broken (if the yarn is broken, the draw ratio at the 4-draw heat treatment step will be lowered, and a sufficiently high IjIM cannot be achieved. This is thought to be due to the thinning behavior becoming unstable and the birefringence Δn of the undrawn yarn becoming high.
The spinning conditions are set to meet the requirement of 0°C. Under spinning conditions that lack this requirement, a high elongational viscosity polymer with RV≧865 is spun, so the Δn of undrawn yarn is
is very high (easily), and as shown in equation (6) above, unless Δn of the undrawn yarn is suppressed to 0.017 or less, K1 will be insufficient.
It is necessary to ensure a stretching ratio of 1l, and it is impossible to obtain high strength and fineness. Among the above conditions, particularly preferred is I#-spinning within a range that satisfies the requirements of formulas (3) to (6') below.

Q/D3 ≦600g/1ea-7(3')D V
w/Q! 6.0ciI/g (4'
)T300 4100℃ (5)
Tsoo: Yarn yarn at position 8oo■ in the yarn discharge direction (from the nozzle surface) Calculated circumference of spun yarn 6■ 9 position O away from the nozzle surface * a degree ('C) Song Gui yarn drawing Δ ≦ 0.018 (6')
If these spinning conditions are set, special elcRY, 44.8
Since the effect of stabilizing the spinning and drawing of the 9 ml mer has been steadily demonstrated, it is preferable to use I lyamide with a thickness of IIu or more for the du amide delicate 1III having an excellent 9 ml polymer of the present invention. 10 This is because the distribution of birefringence in the delicate garden, which is an essential requirement of this Jj II light, is
Ijv-0 relative viscosity is ll! i (This is because it is preferable to
It is impossible to achieve such a roaring Δn.
, on the other hand, the cutting strength decreases.

In addition, when a high-strength spun yarn with low axiality is drawn, the yarn quality will not be as high as shown in the formula in item 1.Also, the position of 80 mm in the yarn discharge direction from the nozzle surface It is special to increase the atmosphere of the yarn yarn 6 ■ separation position 8t1114M.
Chi RV! 4. OOdi l Y-(DΔn) It is effective to reduce the total temperature, and it is desirable to set the temperature to 100°C or higher.Also, if the diameter of the nozzle hole II is set to 04 mφ or less, as is clear from equations 13) and 14), the production You can increase your sexuality. Further, the stretching of the undrawn yarn according to the present invention is 1
．． After giving a preliminary stretching of 10 times or less, the first stage stretching is performed using hot rollers or room temperature rollers, or after the first stage stretching is performed using high temperature pressurized steam at 200 ° C. or higher, the second stage stretching is performed to 100 times or less. It is preferable to carry out the heat treatment at ~200°C. K to adopt any first-stage stretching method
However, in order to stabilize the stretching behavior, it is necessary to carry out stretching at a total stretching ratio of 50 or more in the first stage stretching, and it is preferable that the stretching ratio is higher than 1. Usually 4
．． 6 times or more, especially preferably 6.0 or more is 1i
It's adorable. In the case of roller stretching, the stretching temperature in the single-stage stretch must be 100° C. or lower. 100℃
If this value is exceeded, the V of the yarn becomes unstable on the roller, and the total elongation magnification decreases.

11th meeting! ! When applying high-temperature pressurized steam to grinding, the distance between the yarn and the steam outlet should be within 60 cm, preferably 20 cm.
It is necessary to keep the steam temperature at the steam nozzle from 200°C to 60G'C.

If the temperature is below 600° C., the stretching degree cannot be sufficiently increased, and the drawing point cannot be fixed, and if the temperature is above 600° C., the yarn is likely to melt and break), resulting in poor FK. If the distance between the yarn and the steam outlet is 50 mm or more, the temperature of the yarn at the drawing point will drop considerably, and unless the yarn is run at an extremely low speed, the constant drawing point will not open. be. It is preferable to make the polyamide a1m having excellent strength to reduce the number of yarn contact parts as much as possible in the drawing heat treatment process, for example, I! 2# Fly extension heat treatment process 4C
In this case, non-contact type heaters are effective. A method for stretching at a high draw ratio is to avoid creating voids or defects in the fine edges of the edges.
M! It is a divine effect of Toshinji. In the 8-stage stretching, the key points are the setting of the setting and the stretching conditions of the first stage. By pin or hot plate! Stage, 8th
When stretching columns, virtually! IIL! [Yo] It is also necessary to increase the heat treatment temperature in the 8th stage.
R-jishin at 100-200℃, 8th stage stretching at 160-22℃
It is most preferable to select each from a range of 0°C. It is also effective to carry out stretching using high-temperature, high-pressure jetted steam in the second stage. 4j! At lj Toshin, hot rollers,
After the second stage stretching using a bottle or hot plate is completed, the eighth stage stretching using high temperature and high pressure steam is not performed.
A four-stage stretching method in which a high-temperature heat treatment is subsequently performed is particularly effective. The fiber of the present invention is produced under the above conditions and is characterized by high strength, high knot strength, and high toughness. The superiority of the physical properties of the fibers is closely related to the fine structure of the fibers, and is exerted by a special fine structure that cannot be achieved by the conventionally known a &11# method. When the fiber of the present invention is used for reinforcing rubber etc., it is usually used in the form of a multifilament, but the use of the fiber of the present invention is not particularly limited. , sufu, chirin strands, etc. may be used. # of the invention
am is Iyanid.

In particular, it is suitably used for reinforcing cords in rubber fields, such as carcass cords in V-al structure tires for heavy-duty vehicles, and m* cords for other V-vets, flat belts, toothed baits, etc. Of course, the application of the present invention is not limited to the above-mentioned one, but is used in exactly the same way as the conventional Boria Iso delicacy. The following describes the main method for measuring Patume I used for determining the physical properties of the fiber structure of the present invention.

<Method for measuring relative viscosity> Prepare a sample solution by melting the sample so that the concentration of polymer in the 9g, 8f0.1 weight reagent special*a*i*shank is 1019/di (20 Using an Ostwald viscometer with an ice fall time of 6 to 7 seconds at a temperature of ℃±0.05℃, add m to the relative viscosity of the bath liquid.For measurement, use the same viscometer to adjust the sump A'llll liquid. The same Wtrll as when I did
B G510jl lower 111flllT o (seconds) J
Calculate the relative viscosity RV by the ratio of the time TI (seconds) of the 7"#bath M2Gmg using the following formula.

RV = j1/Tu (
7) <Measurement method of birefringence (Δa)> A Nikon polarization forward imager POH type Tzuits Bereck compensator was used, and a spectral light source activation device (Toshiba 8L8-8-B) was used as a light source (Na light source).6~6
A sample cut at an angle of 46° with respect to the W-length fiber axis is placed on a slide glass with the cut surface facing upward. Place the sample slide Dallas on the rotating stage and rotate the stage once so that the sample is at 467 fK with respect to the polarizer.
iL, after inserting the analyzer and making it a dark field, set the compensator to 80 and count the number of stripes (n pieces). Turn the compensator clockwise until the sample is 111
爾(Naru point's compensator's eye Il&.

Turn the compensator in the right-hand direction Kt and set the scale of the compensator at the point where the sample first becomes one line (read up to the I scale).

Return the compensator to 80, remove the analyzer, determine the sample diameter dt - 1/i based on the formula below.
Calculate birefringence (Δn) (average value of 20 measurements)
.

Δn = r/d (r zm 0 + l)
(Illkowm 589.8mμ C: C/100 in the Leitz compensator manual
m(a-b) (: difference in compensator readings) <Method for measuring Δn distribution in the cross section of the edge pongee> Central refractive index CN obtained using an interference MIIk mirror manufactured by Transmission Quantitative Co., Ltd. top, O,N/,0) and outer layer refractive index (N soil.

0.9, N/, 0.9), it is clear that the fibers of the present invention have a particularly high molecular weight. It gets cloudy. The interference pattern mK obtained using, for example, an interference mirror interface manufactured by Lutzai Jena Co., Ltd., can be used to determine the flat refractive index observed from a delicate even surface. distribution can be measured. This method can be applied to fibers with a circular cross section. The refractive index of a fiber is characterized by the refraction ai (N/) for polarized light vibrating parallel to the fiber axis and the refractive index CN for polarized light vibrating perpendicular to the fiber axis. ζ where #i, all the measurements described are carried out using a xenon lamp as the light source and the refractive index (Nl and Nl) obtained under polarized light using a green light beam with an interference filter wavelength of 644 mμ. Below is the measurement of N/ and Nl, which is obtained
l, Q and Nl, 0.9 will be explained in detail, but NJ
L (Nl, 0 and NJL*0.9) can also be uniformly constant. The fibers to be tested are measured using optically flat slide glasses and cover glasses.
The refractive index (NH
) in a mounting medium that is inert to the fibers MK. The refractive index (NE) of the mounting medium is green light 1111 length λ-544
mμ) was measured using Atsube's refracting needle as a light source.
This is the value at 0°C. The mounting medium used for this purpose is, for example, a mixture of liquid paraffin and a-bromnaphthalene.
A material with a refractive index of ~1.66 can be used as N14. One piece of WtlIIk is immersed in this mounting medium. This interference fringe pattern is photographed, magnified 1000 to 2000 times, and analyzed. The 11th NK abbreviation tlO < The refractive index of the fiber encapsulant is N m λ, the distance between the parallel interference regions of the grasshopper ground (corresponding to 1λ) is DIk%, and the deviation of the edge line interference fringes on the embroidery is d
Let n be the optical path difference. When the refractive index of the sample is Nl, the refractive indices N1 and Nl of the filled liquid are N1(NIN I ) N
Using 2111-4 of g, evaluate the interference fringe I-band as shown in the first iWK.

14 - Lg Therefore, based on equation (9), the average refractive index of the fiber at each position (N
The distribution of l) can be found. The thickness t depends on whether it is calculated by assuming that the obtained fineness is an internal temperature cross section. However, due to variations in manufacturing conditions or changes after manufacturing, there may be cases where the circular cross-section is not formed. Rounding and measuring points to eliminate such inconveniences are i! !
It is appropriate to use a portion where the displacement of the interference fringes is symmetrical with m1llil as the axis of symmetry. When the radius of the fiber is R, the measurement is between 0 and 0.91. This is done at IR intervals and the average refractive index at each position is determined. The distribution of Nl can be found in the same way, so the birefringence distribution is Δn (r/R)=N/, r/R-Nl, r/R
1101 is required. Δn(r/R) is obtained by averaging titrations of 4C on at least 8 filaments, preferably 6 to 10 filaments.

<Method for measuring strength and elongation characteristics of fibers> Using Toyo Baldwin's TENV-Lon, sample length (gauge length) is 100 m, elongation if! Recording speed: 100/min Recording speed: 6
00 m/min, initial load 1/aog/d (D 4e
In this case, the cutting strength (g/d) of the S-8 song of Kosozen is constant.

Cutting elongation M (regret) and Young* (g/d) were calculated.

Young's modulus can be calculated based on the maximum slope near the origin of the S-S curve. Regarding the calculation of each characteristic value, measurements on at least 6 filaments, preferably between 10 and 20 Dy filaments are averaged.

<Measurement method of fiber nodule *M> Using Toyo Bold Twin Ten V-n, sample length 505
A sample consisting of a single diameter g loop of 1 m was attached to the upper and lower chucks of the ten Vron, and attached to the hook, and the gauge length was siO.
, extension speed = 100-/min, recording *xaoo■/min s
-s*- was measured, and the knot breaking strength Jl: (g/d) and the knot breaking elongation (s) were calculated and measured for at least 6 filaments, preferably 10 to go filaments You can get things by averaging them.

Kukotori
The definition of the ll11 scattering pattern can be done using, for example,
The tube voltage was 45 KV and the tube 11 [70 mA] for l determination using the H@ raw equipment (RU-8H micro).

It is made monochromatic with a copper anticathode and a Nikke V filter to produce 9CuKQ (
λ! -1,5418 people). Attach the sample holder KMIMI so that the single threads are parallel to each other. The thickness of the sample is 0.6 to 1. It is appropriate to make it about OU. This parallel arrangement of il!
The diffraction intensity curve is measured by injecting xiIi perpendicularly to the axis of the miscellaneous fibers and rotating a Proportion Concave Null Counter Vifractometer manufactured by Masu Denki Co., Ltd. at an angular speed of 2 seconds/minute. The peak position of the diffraction intensity curve or V! Read the long period small angle scattering angle 2a from the position of V and calculate the fiber long period according to formula 9.09 (see Figure 2, Q3)).

2binα λX=1.6418 people (6)
Hereinafter, the configuration and effects of the present invention will be explained in a different manner by giving an example of a dormitory experience. 111 In the example, "parts" and "-" indicate @p "parts by weight" and "rtt" unless otherwise specified.

Test example 11! 11! Using polycaproamide with a relative viscosity shown as a raw material, spinning was performed under the conditions shown in the same table to obtain a yarn with a birefringence Δm (Il selected at 24 hours at 80°C and 8011RH) and a relative viscosity Niv shown in the table. The heating zone under the 1# nozzle is placed between the nozzle and the cooling zone, and when spinning, an appropriate amount of Q spinning oil is applied to the yarn surface before taking the unjishin yarn. It was attached to.

Igi the nine unearthed divine threads obtained! Stretched under the conditions shown in the table,
A drawn yarn having the quality shown in #18 was obtained.

As is clear from Table 8, the polyamide 1kt embroidery of the present invention (971 Examples 1 to 9) has physical properties that are not as fine as conventional polyamides. On the other hand, in Comparative Example 1, since the relative viscosity of polycaproamide is low, the length of the flat binding molecules tIi4 constituting the yarn is short, and sufficient cutting strength cannot be obtained. In addition, in Comparative Example 2, the T2O was too low and the Δn of the undrawn yarn exceeded the specified value, resulting in poor drawability, cut #41 degrees, and knotting! iiIM is inferior.

[Brief explanation of drawings]

@1 Figure (2) is a schematic diagram showing the interference fringes seen when the fiber of the present invention is subjected to 1111G from the lateral direction using an interference mirror. #@) is a schematic diagram of the new surface of the fiber, wg2 is a schematic diagram showing the arrangement of the sample and film surface in small-angle X-ray diffraction measurement, and (6) is a schematic diagram showing the small-angle X anaphoric diffraction pattern of the fiber of the present invention. It is a diagram. Applicant Toyobo Co., Ltd. (A) Figure 1 Figure 2 2g Age M angle 55-

Claims (1)

[Scope of Claims] The relative viscosity ff (9616-64! Polymer+1fflO cape/sl in an acid aqueous solution, measured at 20°C: hereinafter X1l) of the koji itself is 8.6 or more, and the fiber cross section is The birefringence within is the formula; % formula % (1) is added, and the delicate birefringence Δn is δ0XIG- or more. Cut Wlt9NX (g/d) X (cut 11n+/l”
(1)) ')46.0
(The borea cut edge line has an excellent strength of 1.) At least 476 or more of the borea cut edge line is made of polycaproamide. Polyamide an as described in section. (11 small angle Xi1 diffraction!, i11!l11jljl1
Term #1 G OALU claims 1st or S! Delicate polyamide material. (4) The polyamide fiber according to any one of claims 111 to 8, wherein the carpet has a relative viscosity of 10 or more. (Il shrimp 111M is 60 de=-v or less /U amide iin according to any one of claims 1glN4. 1f1) Claims where the cutting m degree is 11.0 g/d or more F15 Fine polyamide according to any one of item 1. m1lllb spear #8.0 g/d or more Claims W! BJII! The polyamide twill wire according to any one of items 1 to 6.