JPS59168144A - Polyamide sewing machine yarn - 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 The present invention relates to a sewing thread made of polyamide fiber that has excellent sewability and beautiful seams.

Conventional sewing thread made of polyamide fibers has excellent strength and robustness, so it has become widely used in place of cotton sewing thread to meet the Wash and Wear properties of polyester fabrics to be sewn. However, compared to cotton sewing thread, high-speed lockstitching performance was poor, and there were many skipped stitches, which caused sewing problems. The purpose of the present invention is to solve the above-mentioned problems with sewing thread made of polyamide fibers, and to provide excellent high-speed sewing performance for both lockstitch and chain stitch;
The present invention also provides a polyamide fiber sewing thread with less skipped stitches and less occurrence of puckering. That is, the gist of the present invention is that the relative viscosity of the fiber itself (measured in a 96% concentrated sulfuric acid aqueous solution at a polymer concentration of 10 wry/ml at 20°C, the same is 2 or less) is 3.5 or more, and the following (+ )～(
6) It is a polyamide sewing thread made of polyamide fibers that satisfies all of the formulas.

3 △nA-△nB≧0.5X10 -1ll Cutting strength (g/a) x [Cutting elongation (A) 11≧46.0
...(2) Cutting strength (g/a) ≧11.0
...(3) Single fiber denier (d,) ≦6
0...(4) Fiber long period (X)≧100...(5) Birefringence △n≧50X by small-angle X-ray diffraction
10''-3...(61) The polyamide that is the raw material for the fiber intended in the present invention has a relative viscosity of at least 3.5 or more when measured at a polymer concentration of 10 μ/rnl in a concentrated sulfuric acid solution of 96 cm at 20°C, Preferably 4.0 or higher, such as polycaprolactam, polyhexamethylene adipamide, polyhexamethylene sebaamide, copolymers of these polyamides, and 1,4-cyclohexane bis(methylamine) and linear fatty acids. There are polyamides made from condensation products of group dicarboxylic acids as a single material.Such polyamides can be added with matting agents, pigments, light stabilizers, heat stabilizers, antioxidants, antistatic agents, A dyeability improver, an adhesion improver, etc. can be blended, and all can be used except those that have a serious adverse effect on the properties of the present invention depending on the blending.The sewing thread made of the polyamide fiber of the present invention can be used. The strength of the sewing thread is substantially 7.og/a or more.

A drawback of conventional polyamide sewing threads is that during high-speed sewing, the sewing threads are fused and cut by the heated sewing machine needles, resulting in reduced sewability.

To solve this problem, it is desirable to improve the heat resistance of polyamide fibers, but there is a limit to the melting point of polyamide fibers, and it is impossible to dramatically improve heat resistance.

The sewing thread of the present invention does not melt even under high-speed sewing conditions where conventional polyamide sewing thread would easily melt, and even when sewing is continued for 30 seconds at 3000 rpm.
No photocleavage occurs.

The first reason is that the sewing thread has a strength of at least 7 g/d.

In order to make the sewing thread strength 7 g/d or more, it is essential that the polyamide yarn has a strength of 11 g/d or more.

Furthermore, the sewing thread of the present invention has a relative viscosity (RV) of 3.5.
The second reason is that it is made of polyamide with a very high viscosity and high molecular weight, preferably 4.0 or more.

In other words, conventional sewing thread has a relative viscosity of around 3.0 at most, and has a higher viscosity and higher molecular weight, which is effectively equivalent to improving the heat resistance of polymers. it is conceivable that.

The polyamide fiber used in the present invention may be a blend fiber containing a third component or a copolymer fiber. Furthermore, the denier, cross-sectional shape, and short fiber length are not particularly limited.

Polyamide sewing thread made of such polyamide fibers and meeting the above requirements has excellent high-speed sewing properties, low stitch skipping, and is resistant to puckering even in thin woven and knitted fabrics. have a property.

The method for manufacturing sewing thread of the present invention will be described in more detail.

The high-strength polyamide fiber used in the present invention can be obtained by the following method as a result of research by the present inventors.

That is, a polyamide with a relative viscosity RV of )3.5 is mixed with the following polyamide (7
)~a0 Formula is spun under conditions that satisfy formula (1), and by further heat treatment for stretching, the toughness [cutting strength ×
(Cutting Elongation Co., Ltd.) 1'- is 46.0 or more, RVVB is 25, and has completely new structural properties not found in conventional polyamide fibers, such as high bending and high knot strength. This is a method for producing polyamide fibers having the following methods.

Q/D” (982g/sec-m (7
)D -Vw/Q (,,12,8m/g
(s)T2OΣ100℃ (9) △n of undrawn yarn, (0,017(]0) The new structural properties mentioned here refer to the ultra-high RV polymer, which was considered impossible to achieve high strength with conventional technology. It has a fiber cross-sectional circular refractive index distribution not seen in conventional polyamide fibers, and has a microstructure in which the fiber length period determined by small-angle X-ray scattering is longer than that of ordinary polyamide fibers. These structural characteristics are particularly noticeable when polyamides mainly composed of polycaproamide or polyheximethylene adipamide are used. Among these, polycaproamide is Polyamide containing 75% by weight or more is optimal.However, it is difficult to create such a circular refractive index distribution in fiber cross section at an elongational viscosity level where the relative viscosity RV of polyamide is less than 3.5. has an RV of 3.5 or more, more preferably 4.
0 or more must be used. Furthermore, small angle
When the fiber long period determined by line scattering is 100^ or more, high strength properties are improved. Furthermore, when the single fiber denier level is 60 d or less, a structure that satisfies the formula (1) is more likely to be developed and the knot strength is high. In addition, the birefringence △n of undrawn yarn has a very large influence on the total draw ratio.In order to secure a total draw ratio of 4.50 times or more -E, △n of undrawn yarn must be set to 0.01.
It is preferable to set it to 7 or less (however, undrawn yarn △n
is the measured value after 24 hours at 30° C. and 80% RH).

The polyamide fiber having a unique microstructure according to the present invention has a cutting strength of 11, which was quite difficult to achieve with conventional technology.
．． It satisfies the strength properties of 0 g/d or more and knot strength 8.0 g/d or more, and this improvement in cutting strength can be achieved by stretching a polymer with a high relative viscosity and high average molecular weight. This is thought to be because the probability that the number of tie molecules increases is higher than that of molecules with a molecular weight of . The improvement in knot strength is due to the distribution of birefringence within the cross section of the fiber, where the outer layer tends to have a higher birefringence than the inner layer. It is considered that the high toughness of the polyamide fiber according to the present invention,
That is, the reason why the ratio of cutting strength x [cutting elongation] 1/2 is large is that by increasing the molecular weight, high strength can be achieved without causing a decrease in elongation due to excessive stretching. That is, in producing the polyamide fiber according to the present invention, firstly, Q/D'' (-982g/sec -atl
It is essential to set spinning conditions that satisfy the requirement (7). If this condition is lacking, the polymer discharge behavior at the nozzle orifice outlet during spinning will become unstable, resulting in spun yarn breakage or drawn yarn breakage. This occurs frequently, and even if it is possible to draw it, it is not possible to obtain a high-strength yarn. Secondly, the requirement of D2Vw/Q (, 12,8 cup (8)) is also an unreliable spinning condition, and without this requirement,
The spinning tension becomes high, the running of the spun yarn becomes unstable, and yarn breakage occurs frequently. Furthermore, even if the filament is not broken, the draw ratio in the drawing heat treatment step is reduced, and even when the drawing method according to the present invention is employed as well as the usual drawing method, sufficiently high strength cannot be developed. This is considered to be due to the fact that as the spinning tension increases, the thinning behavior of the spun yarn becomes unstable and the birefringence Δn of the undrawn yarn increases.

Thirdly, under spinning conditions that do not satisfy the requirement T2o>100°C (9), △n of the undrawn yarn tends to become very high because a high elongation viscosity polymer called RVVB25 is spun, and as shown in equation (6) above, As described above, unless the Δn of the undrawn yarn is suppressed to 0.017 or less, it becomes difficult to secure a sufficiently high drawing ratio, and a high-strength fiber cannot be obtained. Among the above conditions, it is particularly preferable to carry out melt spinning within a range that satisfies the requirements of the following (7) (+0' formula).

Q/D3 (4500g/5ec-7(7)'D2VW/
Q <5. Om%J7 (8)'T30
0 '2-100℃ (9)'
T3oo = Ambient temperature of the spun yarn at a position 5ff away from the yarn at a position of 300 mrg from the nozzle surface in the yarn discharge direction [°C] △n of undrawn yarn 40.013 (+1
'If these spinning conditions are set, especially R, V) 4.
The effect of stabilizing the spinning and drawing of the polymer No. 50 is significantly exhibited. In carrying out the present invention, it is preferable to use polyamide F having a relative viscosity of 4.0 or more (11). This is because the polyamide fiber having excellent strength preferably has a large distribution of birefringence within the cross section of the fiber, and for this purpose it is preferable to increase the relative viscosity of the polymer. When the distribution of birefringence within the fiber cross section is increased by high-speed spinning, the birefringence △n becomes 50
It is impossible to achieve a high Δn greater than ×10 −3 and the cutting strength becomes low. Furthermore, when a low-viscosity, high-speed spun yarn is drawn, a yarn quality with high so-called "strength" as shown in equation (2) cannot be achieved. However, increasing the ambient temperature at a position 5H away from the yarn at a position 300 in the yarn discharge direction from the nozzle is particularly important for high RV, that is, RV '2-4.
It is effective to lower the Δn of a polymer with a temperature of 0.0, and it is desirable that the temperature is 100°C or higher. Also, if the nozzle hole diameter is set to 0.4 tits O or less, equation (7), (
8) As is clear from the equation, productivity can be increased. Further, in the drawing of the undrawn yarn according to the present invention, after giving a preliminary elongation of 1.10 times or less, first-stage drawing is performed using a hot roller or a room temperature roller (12) or using high-temperature pressurized steam at a temperature of 200° C. or more. After performing the first stage stretching, heat treatment is preferably performed at 100 to 200°C in the second stage stretching. Regardless of which first-stage stretching method is adopted, it is important to perform stretching at 50% or more of the total stretching ratio in the first-stage stretching in order to stabilize the stretching behavior.
Fi is necessary, and the higher the total stretching ratio is, the more preferable it is, usually 4.5 times or more, particularly preferably 5.0 times or more. Further, the stretching temperature in the first stage stretching must be 100° C. or lower in the case of roller stretching.

When the temperature exceeds 100°C, the yarn becomes unstable on the roller and the total draw ratio decreases. In addition, when applying high-temperature pressurized steam to the first stage drawing, the distance between the yarn and the steam outlet is 505 m.
It is necessary to set the temperature within 20 degrees, preferably within 20 degrees, and to keep the steam temperature at the steam nozzle from 200°C to 600°C. If the temperature is 200° C. or lower, the stretching speed cannot be increased sufficiently, and the stretching points cannot be fixed. Furthermore, if the temperature exceeds 600°C, the threads tend to melt and break, making it unstable. If the distance between the yarn and the steam outlet is 50+ m or more, the temperature of the yarn at the drawing point will drop significantly, and it will be difficult to fix the drawing point unless the yarn is run at an unreasonably low speed. In order to produce boria-amizo fibers with excellent strength, it is preferable to minimize the number of yarn contact areas in the drawing heat treatment step. For example, in the second drawing heat treatment step,
Non-contact type heaters are effective. Three-stage stretching or four-stage stretching is effective as a method for stretching at a high stretching ratio without producing voids or grain defects in the fibers. In the three-stage stretching example, the stretching conditions of the second and third stages are important, and ordinary hot rollers, pins,
Alternatively, when performing the second and third stage stretching using a hot plate, it is necessary to make the third stage heat treatment temperature substantially higher than that of the second stage, and the second stage stretching is performed at a temperature of 100 to 200%.
It is most preferable to select the third stage stretching temperature from the range of 160 to 220°C. It is also effective to carry out stretching in the second stage using high-temperature, pressurized steam. In particular, the four-stage stretching method involves completing the second-stage stretching using pot rollers, pins, or hot plates, then performing the third-stage stretching using high-temperature, high-pressure jet steam, and then performing high-temperature heat treatment. It is valid. The fibers used in the present invention are characterized by high strength, high knot strength, and high toughness. The superiority of the physical properties of fibers is closely related to the fine structure of the fibers, and is exerted by a special fine structure that cannot be realized by conventionally known manufacturing methods.

In the method for manufacturing sewing thread of the present invention, conditions similar to those for manufacturing ordinary sewing thread can be selected except for the above-mentioned requirements.

Below, methods for measuring the main parameters used to identify the structure and measure the physical properties of the fibers constituting the sewing thread obtained by the present invention will be described.

<Relative viscosity measurement method 2 Prepare a sample solution by dissolving the sample in 96.3 ± 0.1% by weight reagent special grade concentrated sulfuric acid so that the polymer concentration is 10q/m1Vc, and prepare the sample solution at 20°C ± 0.05'. The relative viscosity of the solution is measured using an Ostwald viscometer with an ice fall time of 6 to 7 seconds at a temperature of C. One time for measurement, using the same viscometer,
The falling time T of 20 ml of sulfuric acid is the same as when preparing the sample solution. (seconds) and the falling time T of the sample solution 20i, (
sec), the relative viscosity RV is calculated using the following formula.

RV = T, /To(II) <Method for measuring birefringence (△n)> A Nikon polarizing microscope POH type Uin Bereck compensator was used, and the light source was a spectral light source activation device (Toshiba 5LS-3- Type B) was used (Na light source). 5～
A sample cut at a 45 degree angle to the fiber axis and having a length of 6 fl is placed on a glass slide with the cut surface facing up. Place the sample slide glass on the rotating stage and adjust the rotating stage so that the sample is at a 45 degree angle to the polarizer.
After inserting the analyzer and making it a dark field, set the compensator to 30 and count the number of stripes (n (i5). Turn the compensator clockwise and the eye of the compensator is the point where the sample first becomes darkest). &as Turn the compensator in the left-hand direction -E until the sample is first K"?I'
i After measuring the scale of the compensator at the darkening point (read up to 1/10 mark in each case), return the compensator to 30, remove the analyzer, measure the diameter d of the sample, and use the following formula. The original birefringence (Δn) is calculated (average value of 20 measurements).

△n = V/d (V = nλ. 1ε) λ =
589.3 C/100 of Niline compensator manual
i determined from 00 and i: (a-b) (: difference in compensator reading)
Nl, 0. N7.0) and outer layer refractive index (N±, 0.
9. The value of Nl, 0.9) reveals the unique molecular orientation of the fiber obtained by Honbori-1, and can show a relationship with the excellent strength of the fiber obtained by the present invention. The distribution of the average refractive index observed from the side of the fiber can be measured by the interference fringe method obtained using a transmission quantitative interference microscope (for example, interference microscope Interfcore manufactured by Karl Zeiss Jena, East Germany).

This method can be applied to fibers with an internal cross section. The refractive index of a fiber is characterized by the refractive index for polarized light vibrating parallel to the fiber axis (N/) and the refractive index for polarized light vibrating perpendicular to the fiber axis (N/). All measurements described here used a Cannon lamp as the light source, under polarized light, and with an interference filter wavelength of 544-P.
(N7 and N soil) obtained using green light.

The following is the N value obtained from the measurement of N7 and N//.

0 and N7. Q, 9[This will be explained in detail, but N1(N
1, O, and N soil, 0.9) can be measured in the same manner as in 1. The fibers to be tested are optically flat glass slides and coverslips.A mounting medium that is inert to the fibers has a refractive index (NE) that provides a shift in the interference fringes within the range of 0.2 to 1 wavelength. immerse in it. Refractive index of mounting medium (
NE) is a value at 20° C. measured using an Atsube refractometer using green light (wavelength λ-544-P) as a light source. This mounting medium can be adjusted to have a refractive index of 1.48 to 1.65 from a mixed solution of liquid paraffin and α-bromnaphthalene, for example. The Kl wood fibers are immersed in this mounting medium.

Photograph this interference fringe pattern and
Analyze at 00x magnification. As shown schematically in Figure 1, the refractive index of the fiber encapsulant is NE, the average refractive index between s/sl/ of the fiber is Nz, the thickness between s'sl/ is t, and the wavelength of the light beam used is λ. The distance between the parallel interference fringes of the ground (corresponding to 1λ) is Dn.

If the deviation of the interference fringes due to the fiber is dn, the optical path difference is expressed as dn. When the refractive index of the sample is Ns, the refractive indices N1 and N2 of the filled liquid are N5 (N.

Using two persimmons with Ns:>N2, the pattern of interference fringes as shown in FIG. 1 is evaluated.

Therefore, based on equation (13), the average refractive index of the fiber at each position (
The distribution of N/) can be obtained.

The thickness t can be calculated by assuming that the obtained fiber has a circular cross section. However, due to variations in manufacturing conditions or accidents after manufacturing, there may be cases where the cross section is not circular.

In order to eliminate this inconvenience, it is appropriate to use a portion to be measured where the displacement of the interference fringes is symmetrical with the fiber axis as the axis of symmetry.

The measurement is performed between O0 and 0.9R, where R is the radius of the fiber.
．． It is possible to obtain the average refractive index at each position by performing the measurement at IR intervals. Similarly, the distribution of N soil can be obtained, so the birefringence distribution is △n (r/R) -Nz, r/R-N soil, r/R (1
4) More required. Δn(r/R) is obtained by averaging measurements on at least 3 filaments, preferably 145 to 10 filaments.

<Measurement method of strength and elongation properties of fibers> Using Tensilon manufactured by Toyo Bold Twin, sample length (gauge length) in order of 100, elongation speed -100%/min recording speed 50
Single fiber S-8 under the conditions of 0 m/min and initial load of 10 g/d.
The curve was measured and the cutting strength (g/d), cutting elongation (%), and Young's modulus (g/d) were calculated. Young's modulus was calculated from the maximum slope near the origin of the SS curve. For the calculation of each characteristic value, at least 5 filaments, preferably 10 to
It is obtained by averaging the measurements for 20 filaments.

<Delicate knot strength measurement method 2 Using Tensilon made by Toyo Bold Twin, a sample consisting of a single fiber with a sample length of 50 degrees loose was placed on the hook sandwiched between the Tensilon upper and lower chucks, and the gauge length was 501 and the elongation speed = S- at 100%/min, recording speed 50011m/min
The S curve was measured, and the knot cutting strength (g/d) and knot cutting elongation (%) were calculated. at least five wooden filaments,
It is preferably obtained by averaging measurements of 10 to 20 filaments.

<Measurement method of fiber long period by small-angle X-ray diffraction> The measurement of the small-angle X-ray scattering pattern is carried out using, for example, an X-ray generator manufactured by Rigaku Corporation (RU-3H type). For measurement, tube voltage 45
KV, a tube current of 70 mA, a copper anticathode, and a CuK-containing tube made monochromatic with a nickel filter (λx=1.5418). Place the fiber sample in the sample holder so that the single threads are parallel to each other. The thickness of the sample is 0.5~
1. It is appropriate to set it to about Otm. X-rays are incident perpendicularly to the fiber axes of these parallelly arranged fibers using a proportional counter prog manufactured by Rigaku Denki Co., Ltd.
Proportional Counter Probe
: 5PC-20) Test A Teifratatometer equipped with P at 8W and 300 positions is rotated at a rotational speed of 2 seconds/min to measure the diffraction intensity curve. Long-period small-angle scattering angle 2 from the peak position or shoulder position of the diffraction intensity curve
Read α and calculate the fiber long period d according to equation (14) (see Figures 2 (A) and (B)).

λx = 1.5418A The configuration and effects of the present invention will be specifically explained below with reference to experimental examples. In the experimental examples, "parts" and "1%" refer to "parts by weight" and "% by weight" unless otherwise specified.

Examples Using polycaproamide with a relative viscosity shown in Table 1 as a raw material,
Spinning was carried out under the conditions shown in the same table, and the birefringence △ shown in the same table was
An undrawn yarn with a relative viscosity of RV (measured after waiting for 24 hours at 30'C and 80% RH) was obtained. The heating zone below the nozzle was placed between the nozzle and the cooling zone, and during spinning, an appropriate amount of spinning oil was applied to the surface of the yarn before taking off the undrawn yarn.

Each of the obtained undrawn yarns was drawn under the conditions shown in Table 2.
A drawn yarn having the quality shown in the table was obtained.

As is clear from Tables 1 to 3, the fibers (Examples 1 to 9) constituting the sewing thread of this invention show excellent values in all yarn qualities, compared to the comparative examples. In No. 1, since the relative viscosity of polycaproamide is low, the average molecular chain length constituting the yarn is short, and sufficient cutting strength cannot be obtained. Furthermore, in Comparative Example 2, T2o is too low and Δn of the undrawn yarn exceeds the specified value, resulting in poor drawability and failure to satisfy the cutting strength and knot strength.

Next, 100 drawn yarns (filaments) of Example 8 were combined, then first twisted, three yarns were combined, further twisted, and then heated to 100°C'? Dye it and make it into sewing thread.

When this sewing thread was used to stack four layers of plain fabric (weighing 150 g/i) made of 65% polyester and 35% rayon and sewn at a sewing speed of 3000 rpm, the sewing thread did not break in 1 minute. Ta.

In addition, the strength of this example was approximately 50% higher (cutting strength 8-9 g/d) compared to the conventional polyamide sewing thread, and the stitchability was good, with almost no skipped stitches. .

[Brief explanation of drawings]

Figure 1 (A) is a schematic diagram showing the interference fringes seen when the fiber obtained according to the present invention is observed from the side with a microscope; Figure 1 (B) is a schematic diagram of the cross section of the fiber; (A) is a schematic diagram showing the arrangement of the sample and film surface in small-angle X-ray diffraction measurement, and (B) is a schematic diagram showing the small-angle X-ray diffraction pattern of the fiber obtained by the present invention. T Serimu Applicant: Toyobo Co., Ltd. - Prohibition proceedings Amendment: Rose (voluntary) May 19, 1980 & Relationship with the case of the person making the amendment Patent applicant 2-2-8-4 Dojimahama, Kita-ku, Osaka Subject of the amendment (1) Detailed description of the invention in the specification & Contents of the amendment (1) Specification No. Change “100 books” on line 28111 to “
Corrected to 10 books. Procedures Amendment (spontaneous) L Indication of the case 1981 Patent Application No. 403'79 2 Name of the invention Zaryamide Sewing Machine Thread & Person making the amendment Relationship to the case Patent applicant 2-2 Dojimahama, Kita-ku, Osaka No. 8 student Replace with Table 1 of the type print subject to correction. Replace with Table 1 of type mark d. (2) Table 2 on page 26 of the same specification shall be replaced with Table 2 on the separate type print. (8) Replace Table 3 of Section 27 of the same specification with Table 3 of the separate type print. 1-1

Claims (1)

[Claims] 1. The relative viscosity of the fiber itself (measured at a polymer concentration of 10 cm/-120°C in a 96-ton concentrated sulfuric acid aqueous solution; the same applies hereinafter) is 3.5 or more, and ) ~ (Polyamide sewing thread made of polyamide fibers that satisfies all formulas 61. △nA-△na≧0.5 ≧46.0
, (2j cutting strength (g/d)≧1140...
・(3) Single fiber denier (d)≦60...(4
) Fiber long period (A)≧100 by small-angle X-ray diffraction
(5) Birefringence △n≧50×10-3...
(6)