JP3193933B2 - Polyester sewing thread - Google Patents

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 which is excellent in dyeability and high-speed sewability and maintains high strength even after sewing.

[0002]

2. Description of the Related Art Sewing threads are required to have good thermal dimensional stability, good dyeing properties, good high-speed sewability, and the like. In order to satisfy these required characteristics, for example, Japanese Patent Publication No. 4-1456 / 1992 discloses a polyester sewing thread having excellent seamability and a beautiful seam, and the birefringence in the fiber cross section is doubled in the fiber outer layer. Fibers with higher and higher degrees of crystal orientation have been proposed. Japanese Patent Application Laid-Open No. 61-34218 discloses that the correlation between the spinning speed and the intrinsic viscosity of the fiber is specified to suppress a decrease in the strength of the original yarn for the sewing thread, and to improve heat resistance and high-speed sewability. There has been proposed a method of obtaining a raw yarn for polyester sewing thread having the same.

[0003] However, in all of the proposed sewing threads or sewing thread for sewing machines, the polymer has a high degree of crystal orientation, so that the dyeing property, which is one of the required properties of the sewing thread, is not always satisfied. I can't say that.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester sewing thread having excellent dyeability, high-speed sewability and heat resistance.

[0005]

An object of the present invention is to provide a polyester fiber comprising ethylene terephthalate as a main repeating unit, the polyester fiber having an intrinsic viscosity of at least 0.8 and a glass transition temperature of 80. C. or lower, specific heat of 2.0 J / g.degree. C. or higher, cutting strength of 6.0 g / denier or higher, and cutting elongation of 30% or lower.

The polyester used in the present invention is a polyester containing ethylene terephthalate as a main repeating unit. Preferably, 90 mol% or more of the repeating unit is ethylene terephthalate, and less than 10 mol% is a polyester which may be copolymerized with other components. Such copolymerization components include aromatic dicarboxylic acid components such as isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, and 5-sodium sulfoisophthalic acid; aliphatic dicarboxylic acid components such as adipic acid and sebacic acid; Oxycarboxylic acid components such as oxybenzoic acid and p-oxyethoxybenzoic acid; polyvalent carboxylic acid components such as trimellitic acid and pyromellitic acid;
, Tetramethylene glycol, hexamethylene glycol, propylene glycol, neopentyl glycol
And diol components such as 1,4-cyclohexanedimethanol.

The polyester fiber which is the raw thread of the sewing thread of the present invention must satisfy the following physical properties. First, the intrinsic viscosity needs to be 0.8 or more. If it is less than 0.8, the sewability and strength of the sewing thread will be poor. Normal,
In the process of converting the fiber into a sewing thread, for example, in the process of twisting such as priming and plying, or in the dyeing process, the strength is significantly reduced. Therefore, the upper limit of the intrinsic viscosity is not particularly limited, but the intrinsic viscosity is preferably higher at the stage of the raw yarn, and is preferably in the range of 0.9 to 1.1. In order to obtain a fiber having such an intrinsic viscosity, it is preferable that the intrinsic viscosity of the polyester be 1.0 to 1.2.

Further, the glass transition temperature (hereinafter referred to as Tg) needs to be 80 ° C. or less. Tg is 80
If the temperature exceeds ℃, the dyeability of the sewing thread is inferior. Also,
When the teeth are dyed, stain spots are likely to occur between the inner layer and the outer layer of the cheese. In order to further enhance the dyeability of the sewing thread, it is preferable that the Tg at the raw yarn stage be 75 ° C. or less. In the case of performing the cheese dyeing, in order to eliminate the above-mentioned stain spots, it is preferable to use a yarn having a boiling water shrinkage of 2.5% or less, preferably 1.5 to 2.0%. desirable.

The specific heat of the polyester fiber is 2.0 J / g ·
It is necessary to be higher than or equal to ° C. If it is less than 2.0 J / g · ° C., there is a problem that the strength of the sewing thread largely decreases before and after sewing due to the action of heat generated by friction between the cloth and the sewing needle, and the sewing thread breaks during sewing. Therefore, in order to suppress a decrease in strength before and after sewing the sewing thread, that is, to improve the heat resistance of the sewing thread, it is preferable that the specific heat at the raw yarn stage be 2.1 J / g · ° C. or more. .

The strength of the polyester fiber is required to be 6 g / denier or more. If it is less than 6 g / denier, the strength is significantly reduced due to mechanical deterioration such as impact and fatigue due to high speed rotation of the sewing machine during sewing, action of frictional heat, and the like,
The sewing thread breaks. Therefore, the strength is preferably higher at the raw yarn stage, and is preferably 7 g / denier or more.

Further, the elongation of the polyester fiber must be 30% or less. If it exceeds 30%, the Young's modulus of the fiber will be low, and the sewing thread will not be stiff. In addition,
It may also cause skipping during mucking and sewing. Preferably, the elongation is in the range of 15-20%.

It has been stated that, as the polyester having the above-mentioned physical properties, it is preferable that at least 90 mol% of the repeating units be ethylene terephthalate. For improvement, it is preferable to add only a glass transition point depressant (hereinafter, referred to as a Tg depressant) or a combination of a Tg depressant and solid fine particles to the polyester.

The Tg lowering agent is defined as a Tg lowering agent when 2% by weight of the Tg lowering agent is added to the polyester used in the present invention.
An additive having the property of lowering the glass transition temperature of the polyester by 2 ° C. or more as compared with the case where no depressant is added. The glass transition temperature of the polyester can be easily measured by a differential scanning calorimeter or the like.

As the Tg lowering agent, any one having the above properties can be used, but the following general formula (I):

R ↑ 1O—X—OR ↑ 2 (I) (wherein X is an aromatic group, and R ↑ 1 and R ↑ 2 have 6 to 6 carbon atoms.
(Representing an alkyl group or arylalkyl group of 18).

In the compound represented by the general formula (I),
Preferred examples of the aromatic group X include the following formulas (II) to (II).
And a divalent group represented by (IX).

[0017]

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[0018]

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[0019]

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[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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Further, Tg suitable for use in the present invention
As the depressant, for example, the following general formulas (X) to (XII)
The compound represented by I) can be mentioned.

[0026]

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[0027]

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[0028]

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[0029]

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The addition amount of the Tg lowering agent is preferably in the range of 0.5 to 10% by weight based on the weight of the polyester. When the addition amount of the Tg lowering agent is less than 0.5% by weight,
If the effect of improving the dyeability is not exhibited, and if it exceeds 10% by weight, the sewability of the sewing thread is undesirably reduced. More preferably, it is in the range of 1 to 5% by weight.

The solid fine particles have an average particle size of 1
Inorganic fine particles in the range of 5 to 70 mμ, more preferably 30 to 50 mμ, are desirable. When the particle diameter of the solid fine particles is less than 15 mμ, the friction durability of the obtained fiber is insufficient, while
If it exceeds 70 μm, the fibers tend to be fibrillated, which is not preferable. The surface of the solid fine particles may be modified by introducing an aluminum coat or an alkyl group. Examples of the solid fine particles used in the present invention include silica, alumina, kaolin, calcium carbonate, and titanium oxide.
In particular, silica having an average particle diameter of 15 to 70 mμ and a refractive index of 1.65 or less is preferred for imparting transparency and the distinctive color clarity of the cationic dye to the fiber.

The amount of the solid fine particles to be added is preferably in the range of 0.1 to 3.0% by weight based on the weight of the polyester. If the added amount of the solid fine particles is less than 0.1% by weight, the high-speed sewability as a sewing thread is inferior. More preferably, 0.3 to 2.0% by weight
Range.

The timing and method of adding the Tg lowering agent and the solid fine particles to the polyester are not particularly limited. For example, even if the Tg lowering agent and the solid fine particles are added simultaneously,
Also, they may be added at completely different times. Further, the Tg lowering agent and the solid fine particles may be added at an appropriate time before or after the polymerization of the polyester, or may be added during melt spinning.

The polyester fiber of the present invention can be easily obtained by a general melt-spinning method, and the obtained spun yarn can be drawn by an ordinary method. For example,
After preheating with a heating roller in the range of 70 to 95 ° C. which is equal to or higher than the glass transition temperature of the polyester, stretching is performed in a range of 3.0 to 5.0 times, which is a stretching ratio according to the speed of the winding roller, 150 to 18 which is higher than the crystallization temperature of the polyester
What is necessary is just to heat-treat in the range of 0 degreeC. Further, a method in which spinning and drawing are directly connected, such as a spin draw, may be used.

[0035]

When a Tg-lowering agent or a Tg-lowering agent and solid fine particles are added to a polyester fiber containing ethylene terephthalate as a main repeating unit, dyeability and high-speed sewability can be simultaneously satisfied. By using a Tg depressant and solid fine particles together, the specific heat of the polyester increases, and even under high-speed sewing conditions where a conventional sewing thread made of polyester fiber is easily cut off, the specific heat of the polyester fiber is high because the specific heat of the polyester fiber is high. It is difficult for the yarn temperature to rise, and for the yarn to hardly melt.

[0036]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited thereto. In addition, each physical property in an Example was measured and calculated | required by the following method. (1) Intrinsic viscosity of fiber ([η]) The fiber was prepared by mixing phenol / tetrachloroethane (weight ratio 1:
It melt | dissolved in the mixed solvent of 1), and measured at 30 degreeC. (2) Glass transition temperature of fiber Tg (° C.) Using a differential scanning calorimeter (DSC: TA3000, manufactured by Metra Corporation), 10 mg of a sample was heated from 50 ° C. to 300 ° C. at a rate of 20 ° C./min in a nitrogen atmosphere. And then left for 3 minutes, rapidly cooled to room temperature, again in a nitrogen atmosphere, at a heating rate of 1
The temperature was raised to 300 ° C. at 0 ° C./min and determined from the DSC curve. (3) Specific heat of fiber (J / g · ° C.) Using a DSC, 10 mg of a sample was heated from 50 ° C. to 280 ° C. in a nitrogen atmosphere at a rate of 10 ° C./min.
The specific heat at ° C was determined. (4) Fiber breaking strength (g / d) and elongation (%) Measured and determined in accordance with JIS L 1013. (5) Shrinkage rate of boiling water (%) After measuring the original length (cm) of a 10-wound wrap around 1 m per lap under a load of 0.1 g / denier, it was treated in boiling water for 15 minutes to obtain 0.1 g. / Length after treatment under denier load (c
m) was measured and calculated by the following equation. Boiling water shrinkage (%) = [(Original length-Length after treatment) / Original length]
× 100 (6) Sewability Five blended twill 6200S made of polyester fiber and cotton were stacked to form a sewing fabric, and Union Special 63400A type (sewing machine needle No. 14) was used as a high-speed sewing machine. A sewing test was performed at 3750 rpm of the number of needles of the sewing machine, and the sewing length until the thread was cut was measured. The longer the sewing length, the better the sewability. (7) Dyeing properties The drawn polyester yarn was knitted into a tube, and dyed in boiling water at 3% owf using Eastman polyester navable as a dye. After the staining, the cells were heat-fixed and the color difference was determined. The judgment was made in five stages, and the higher the value, the higher the value. The dyeing was performed in the same bath.

Example 1 [η] = 2% by weight of a Tg depressant represented by the general formula (XII) and 1% by weight of silica having an average particle size of 30 μm
Polyethylene terephthalate of 0.98 has a spinning speed of 13
Melt spinning and stretching at 00 m / min, 70 denier 2
A 4-filament raw yarn for a sewing thread was obtained. The obtained raw yarn was twisted and ply-twisted to form three yarns, and dyed at 130 ° C. Then, the sewing thread obtained was tested for sewability. The physical properties of the original thread for sewing and the sewing thread were measured, and the results are shown in Table 1.

Example 2 Polyethylene terephthalate of [η] = 1.20 containing 2% by weight of a Tg lowering agent represented by the general formula (XII) was melt-spun and drawn at a spinning speed of 1000 m / min. ,
A 70 denier 24 filament raw yarn was obtained. The obtained raw yarn is twisted and plied three times to form a single yarn.
Stained at 30 ° C. Then, the sewing thread obtained was tested for sewability. The physical properties of the original thread for sewing and the sewing thread were measured, and the results are shown in Table 1.

Comparative Example 1 A yarn for sewing was obtained in the same manner as in Example 1 except that no Tg-lowering agent was added.
Three twisted yarns were twisted and twisted and dyed at 130 ° C. Then, the sewing thread obtained was tested for sewability. The physical properties of the original thread for sewing and the sewing thread were measured, and the results are shown in Table 1. Compared to the yarn obtained in Example 1, the yarn has the same intrinsic viscosity, but has a high Tg and a low specific heat, so that not only the sewing property but also the dyeing properties of the sewing thread are significantly inferior. Was.

Comparative Example 2 A yarn for sewing was obtained in the same manner as in Example 1 except that solid fine particles were not added.
Three twisted yarns were twisted and twisted and dyed at 130 ° C. Then, the sewing thread obtained was tested for sewability. The physical properties of the original thread for sewing and the sewing thread were measured, and the results are shown in Table 1. Compared with the original yarn obtained in Example 2, the intrinsic viscosity of the original yarn became smaller and the specific heat became smaller, and the sewability as a sewing thread was significantly inferior.

Comparative Example 3 A raw yarn for a sewing machine was obtained in exactly the same manner as in Example 1 except that the Tg depressant and the solid fine particles were not added. 130
Stained at ° C. Then, the sewing thread obtained was tested for sewability. The physical properties of the original thread for sewing and the sewing thread were measured, and the results are shown in Table 1. Compared with the yarn obtained in Example 1, although the yarn has the same intrinsic viscosity, the Tg is high and the specific heat is small, so that not only the sewing property but also the dyeability of the sewing thread were inferior. .

[0042]

[Table 1]

[0043]

The sewing thread obtained in the present invention is excellent in dyeability and high-speed sewability, and does not decrease in strength even after sewing.
It is of high industrial value.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-34218 (JP, A) JP-A-4-228612 (JP, A) JP-A-2-210037 (JP, A) JP-A 63-342 315633 (JP, A) JP-A-3-124876 (JP, A) JP-A-59-211638 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D02G 3/00-3 / 46 D01F 6/62

Claims (1)

(57) [Claims] 1. A polyester fiber comprising ethylene terephthalate as a main repeating unit, having an intrinsic viscosity of 0.8 or more, a glass transition temperature of 80 ° C. or less, and a specific heat of 2.0 J / g · ° C. or more. A sewing thread made of polyester fiber having a cutting strength of not less than 6.0 g / denier and a cutting elongation of not more than 30%.