JPH06108334A - Machine sewing thread of polyester - Google Patents

Abstract

PURPOSE:To obtain machine sewing thread of polyester slightly causing packering, forming a beautiful stitch free from end breakage and skip stitch. CONSTITUTION:Constituent filament constituting machine sewing thread comprising polyester fiber having ethylene terephthalate as a main repeating unit has (1) dry heat shrinkage percentage HS<=1.5% at 150 deg.C, (a) temperature-dependent parameter of shrinkage percentage DELTAHS/T<=0.04%/ deg.C, (3) initial tensile resistance Mi>=105g/d, (4) peak temperature of dynamic loss tangent Tmax<=135 deg.C and (5) crystallinity index Xc<=55% to give machine sewing thread of polyester.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester sewing thread having excellent seamability and beautiful seams.

[0002]

2. Description of the Related Art Sewing threads made of conventional polyester fibers have high strength, high modulus, and excellent dimensional stability.
It is widely used for clothing and industry because it has little change in physical properties over time. However, in the conventional polyester sewing thread, many stitch skips occur when sewing at high speed,
There is a problem that a lot of puckering occurs when the product is press-dried. Various improvements have been made to date for these problems. For example,
JP-A-52-63454, JP-A-60-3942
As shown in Japanese Patent Publication No. 9, a polyester sewing machine thread is known, which is aimed at improving sewing by spinning at a speed of 2000 to 6000 m / min and stretching. However,
With these methods, the thermal shrinkage is still large and the initial tensile resistance is small, so that sufficient improvement cannot be achieved.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polyester sewing thread which does not cause puckering and is free from thread breakage and stitch skipping when sewing at high speed and forms a beautiful seam. Especially.

[0004]

DISCLOSURE OF THE INVENTION As a result of intensive studies aimed at solving such problems, the present inventors have solved the above problems by producing fibers having a specific structure by a specific spinning and drawing method. As a result of knowing what can be done, the present invention has been achieved. That is, in a sewing thread made of polyester fiber having ethylene terephthalate as a main repeating unit,
The constituent filaments have a dry heat shrinkage at 150 ° C. HS ≦ 1.5%, and a temperature dependence parameter of the shrinkage ΔHS / T ≦ 0.0.
4% / ° C Initial tensile resistance Mi ≧ 105 g / d Peak value of mechanical loss tangent tan δ ≦ 0.14 Peak temperature of mechanical loss tangent Tmax ≦ 135 ° C. Crystallinity Xc ≧ 55% It is a sewing thread.

The present invention will be described in detail below. The polyester of the present invention means 85 mol% or more, preferably 90 mol% of ethylene terephthalate repeating units in the molecular chain.
As described above, more preferably, the polyester contains 95 mol% or more. Polyethylene terephthalate is preferably used as the polyester, but other copolymerization components may be contained in a proportion of less than 15 mol%, preferably less than 10 mol%, more preferably less than 5 mol%.
Examples of such a copolymerization component include, for example, isophthalic acid,
Examples thereof include naphthalenedicarboxylic acid, adipic acid, oxybenzoic acid, diethylene glycol and 1-4 butanediol. Also, for these polyesters, stabilizers,
It does not matter even if it contains matting agents, coloring agents, etc.

The intrinsic viscosity of polyester fiber is 0.45.
It is preferable to be 0.8 to 0.85, and more preferable to be 0.
It is 5 to 0.75. If it is less than 0.45%, it is difficult to obtain strength, and if it exceeds 0.85, it is difficult to obtain strength. The polyester sewing machine thread of the present invention has a dry heat shrinkage ratio at 150 ° C. of 1.5% or less, preferably 1.0% or less.
If the dry heat shrinkage exceeds 1.5%, a large amount of puckering occurs when the product is sewn and then dried by heat.

The temperature-dependent parameter of the dry heat shrinkage is 0.04% / ° C. or less, preferably 0.03, more preferably 0.025. The temperature-dependent parameter of the dry heat shrinkage is the result of measuring the change gradient of the dry heat shrinkage with respect to temperature from the 150 ° C. dry heat shrinkage and the 200 ° C. dry heat shrinkage by the method described later. The smaller this parameter, the less structural change with temperature. This is because there is little change in the fine structure of the fiber due to the temperature rise during dyeing and sewing,
This means that there is little reduction in initial tensile resistance. Therefore, the occurrence of skipped stitches at the time of high-speed sewing of the final product sewing thread is linked.

The polyester sewing machine thread of the present invention has an initial tensile resistance of 105 g / d or more. If it is less than 105 g / d, skipping is likely to occur during high-speed sewing, which is not preferable. It is possible to make it 105 g / d or more by the conventional technique, but at that time, the dry heat shrinkage ratio becomes high, the temperature dependence parameter of the dry heat shrinkage ratio becomes large, and at the same time, the requirements of the present invention are satisfied. Can not do it. Therefore, even if the initial tensile resistance is set to be high, the initial tensile resistance is greatly reduced due to the shrinkage due to the heat when dyeing the sewing machine thread, and the initial tensile resistance is reduced due to the heat generated during sewing. The problem of skipping stitches when sewing cannot be avoided. For example, in the above-mentioned conventional technique, when the initial tensile resistance of the present invention is set, the dry heat shrinkage ratio is 3.0.
%, The temperature-dependent parameter exceeds 0.04, but in the present invention, the dry heat shrinkage ratio is 1.5% or less, and the temperature-dependent parameter becomes 0.04 or less. Therefore, the present invention achieves a great improvement in terms of puckering and skipping during high-speed sewing.

The peak value tan δ of the mechanical loss tangent of the polyester sewing machine thread of the present invention is 0.14 or less, and the peak temperature Tmax is 135 ° C. or less, more preferably 1
It is 30 ° C or lower. If tan δ exceeds 0.14, sufficient orientation cannot be obtained and the initial tensile resistance cannot satisfy the requirements of the present invention. On the other hand, when Tmax exceeds 135 ° C., the strain in the amorphous part is not sufficiently relaxed, and the low heat shrinkage cannot be achieved as in the present invention.

The crystallinity of the polyester sewing thread of the present invention is 55% or more, preferably 60% or more. When the crystallinity is less than 55%, it is not possible to obtain a polyester sewing thread having a high initial tensile resistance and a low heat shrinkage ratio. As described above, in the fine structure of the fiber, the crystal part is sufficiently developed, while the amorphous part is sufficiently relaxed, so that the yarn breakage during high-speed sewing is extremely reduced.

The method for obtaining the polyester sewing thread as described above includes the following methods. A polyester containing ethylene terephthalate as a main repeating unit is melt-spun by a usual screw extruder. At this time,
The temperature of the extruded polymer is preferably maintained in the range of 270 ° C to 320 ° C, and the pore diameter of the spinneret is 0.2 to 1.0.
mm, denier per filament of spun yarn is 1
It is preferably 10 to 10.

The spun yarn discharged from the spinneret has a length of 5 cm or more and an internal atmosphere temperature of 150 ° C. to 35 ° C.
Pass through a heating zone that is 0 ° C. Then, 10 ~ 30 ℃
It is cooled and solidified by blowing some cold air by a known method. The method of blowing cold air may be a known method, but it is preferable to blow cold air from the outer periphery in consideration of yarn breakage during spinning and drawing and easiness of operation.

Then, after being cooled and solidified, it is wound at a speed of at least 6.0 Km / min, preferably 6.5 Km / min using an oiling guide as a focusing guide. The birefringence of the spun yarn thus obtained is 1.15 or more, which is a highly oriented spun yarn. The spun yarn obtained as described above may be once wound and then separately drawn, or may be directly drawn without being wound. The stretching treatment is performed in one stage or in multiple stages of two or more stages. The drawing speed in the case of separate drawing is arbitrary, but 500 considering the balance between yarn breakage and productivity.
The range of up to 3000 m / min is preferred.

When a stretching treatment is carried out, the stretch ratio of the obtained fiber is 8% to 18%, preferably 9% to 15%.
The draw ratio is determined so that When the draw ratio is set so that the elongation is less than 8%, the yarn breaks frequently during the drawing.
On the other hand, if it is 18% or more, the strength and initial tensile resistance of the obtained fiber are insufficient. The specific draw ratio varies depending on the birefringence of the spun yarn obtained, but in the case of the polyester fiber of the present invention, it is generally in the range of 1.1 to 1.5.

At this time, the stretching temperature is set in the range of 50 to 250 ° C. and the stretching treatment is carried out. After the above stretching, subsequently, 0.9 to 1.0 times, the temperature 180 ℃ ~ 250 ℃
Relax heat treatment is performed within the range. By this relaxing heat treatment, the stress strain caused by stretching is uniformly relaxed, and the raw yarn for sewing yarn having the physical properties of the present invention can be obtained.

[0016]

The present invention will be described with reference to the following examples. The measurement methods used in the examples are as follows. (1) Intrinsic viscosity [η] Using an Ostwald viscometer, orthochlorophenol was used as a solvent, and the viscosity was measured in a constant temperature bath at 35 ° C. (2) Strength TS, elongation E, initial tensile resistance Mi using Shimadzu Autograph SS-100 type, yarn length 20c
m, the tensile speed was 100% / min, and the initial tensile resistance was defined as the strength gradient at 1% elongation from the strength-elongation curve. (3) Heat shrinkage rate HS and temperature dependency parameter of shrinkage rate ΔHS / T The sample length was 100.0 cm, and after free shrinking for 30 minutes in an air oven at 150 ° C. and 200 ° C., the yarn length was measured. It was calculated by the formula.

HS (%) = {(100.0-l) /100.0} × 100 l: Yarn length after heat treatment Also, the temperature dependence parameter ΔHS / T of the shrinkage ratio was obtained by the following formula. ΔHS / T (% / ° C.) = (HS ₂₀₀ −HS ₁₅₀ ) / 50 HS ₂₀₀ : 200 ° C. heat shrinkage ratio HS ₁₅₀ : 150 ° C. heat shrinkage ratio (4) Crystallinity Xc Carbon tetrachloride / adjusted by n-heptane The density ρ was measured at 25 ° C. using the density gradients thus obtained, and calculated by the following formula.

Xc (%) = {ρ _c (ρ−ρ _a ) / ρ (ρ _c −ρ _a )] × 100 ρ _c : 1.455 g / cm ³ ρ _a : 1.335 g / cm ³ (5) Birefringence [Delta] n It was measured by a retardation method using a polarizing optical microscope manufactured by Olympus, using sodium D ray as a light source, [alpha] -bromonaphthalene / olive oil as an immersion liquid, and a Berek compensator. (6) Mechanical loss tangent tan δ and peak temperature Tmax Using a rheovibron DDV-II type dynamic viscoelasticity measuring device manufactured by Toyo Baldwin Co., Ltd., tan δ at each temperature was measured at a measurement frequency of 110 Hz and a heating rate of 5 ° C./min. It was measured. Here, for convenience, the peak value is defined as tan δ, and the temperature at that time is defined as Tmax. (7) Sewability test Four pieces of blended Surge T2001 made of 55% polyester fiber and 45% rayon were layered together to make a sewn fabric.
Using the i-DLD43A type high-speed sewing machine, use sewing machine needle No. 14, and perform a sewing test at 6000 rpm.
The time to break was measured. (8) Puckering test Two pieces of blended Surge T2001 made of 55% polyester fiber and 45% rayon are piled up and sewing pitch is 14 stitches / 2.
Sew 5 cm, wash for 20 minutes in home washing machine, rinse 4
After 0 minutes and dehydration, the product was treated with a press dryer at 200 ° C. for 15 seconds at a press pressure of 2 Kg / cm ² and visually evaluated according to the following criteria.

Grade 5: Almost no waviness is observed. Grade 4: The waviness is slight. 3rd grade: Waves are noticeable. Level 2: The wave is pretty bad. Grade 1: The waviness is remarkable. (9) Skipping property 4 pieces of blended Surge T2001 made of 55% polyester fiber and 45% rayon are piled up to form a sewn fabric.
Using the i-DLD43A type high-speed sewing machine, use sewing machine needle No. 14 and perform a sewing test with the number of rotations of 5000 rpm.
The skipped state was judged according to the following criteria.

B: Almost no skipping is observed. Δ: Skipping is observed. X: Remarkable skipping. As shown in Table 1, polyethylene terephthalate chips having an intrinsic viscosity of 0.52 to 0.80 were used, and the spinning temperature was 295 ° C.
And was spun at a spinning speed of 3.0 to 8.0 km / min to obtain a spun yarn having a birefringence of 0.035 to 0.151. In addition, as the spinneret, a spinneret in which 24 holes of nozzles having a hole diameter of 0.35 mm are concentrically arranged is used, and after discharging from the spinneret,
As shown in Table 1, a heating zone having a length of 15 to 25 cm set at a temperature of 250 to 300 ° C. is passed, and a temperature of 20 from the outer periphery is passed.
Chilling cold air was blown at 0.3 m / sec, and it was wound using an oiling nozzle as a focusing guide.

The above spun yarn was treated with the first roller at a temperature of 70 ° C.
Second roller temperature 150 ° C, third roller temperature 240
And a fourth roller temperature of 240 ° C. were used, and the treatment was carried out at a stretching ratio shown in Table 1 to 1500 m.
It was wound up at a speed of 1 / min to obtain a polyester fiber of 70 denier and 24 filaments. In addition, at the draw ratio in the table, DR1
Is the speed ratio of the second roller to the first roller, DR2
Is the speed ratio of the third roller to the second roller, R1 is the speed ratio of the fourth roller to the third roller, and R2 is the speed ratio of the winder to the fourth roller. The physical properties of the drawn yarn obtained at this time are shown in Table 1. Experiment No. 1
6 to 6 are examples of the present invention, and experiments 7 to 10 are comparative examples.

Then, each of the obtained drawn yarns was 880T.
/ M undertwisting, 560T / m overtwisting while making 3 ply yarns, heat setting, then 130
Dye under the conditions of 40 ° C for 40 minutes and add 3% of silicone oil
The attached finishing treatment was performed and wound up on a bobbin for sewing thread. The results of performance evaluation of this sewing thread are shown in Table 1. Experiment No. of the present invention. Nos. 1 to 6 have good sewability during high-speed sewing, less skipping, and less puckering after press drying. On the other hand, the comparative experiment No. 7-
No. 10 has a poor sewing thread performance.

[0023]

[Table 1]

[0024]

EFFECTS OF THE INVENTION The polyester sewing machine yarn of the present invention has a highly drawn crystalline yarn, the amorphous portion is sufficiently relaxed, low heat shrinkage, high initial tensile resistance, and structural change with temperature. Since there are few sewing threads, the thread breakage during high-speed sewing is small.

Fewer stitch skips at high speed sewing. Little puckering when heat-dried. And so on.

Claims (1)

[Claims] 1. In a sewing machine thread composed of polyester fibers containing ethylene terephthalate as a main repeating unit, the constituent filaments have a dry heat shrinkage ratio HS ≦ 1.5% at 150 ° C. and a temperature dependence parameter ΔHS / T ≦ 0 of the shrinkage ratio. .0
4% / ° C Initial tensile resistance Mi ≧ 105 g / d Peak value of mechanical loss tangent tan δ ≦ 0.14 Peak temperature of mechanical loss tangent Tmax ≦ 135 ° C. Crystallinity Xc ≧ 55% Sewing thread.