JP2002227050A - Sewing yarn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewing yarn solving a shrinkage by sewing of a seam and a deformation, having an excellent appearance quality of the seam, easily degradable in natural environment and suitable for a biodegradable cloth. SOLUTION: This sewing yarn is obtained by performing final twist on a plurality of multifilament yarns subjected to first twist and combining and is characterized by having -2 to 5% shrinkage percentage calculated by adding shrinkage percentage by dry heat and shrinkage percentage by boiled water and 10-50% lowering ratio of strength in a soil for one year and comprising an aliphatic polyester as a part of the ingredient composing the sewing yarn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing thread made of an aliphatic polyester fiber thread, and more particularly, the present invention relates to a sewing thread having excellent seam quality while making use of the vivid coloration and luster of an aliphatic polyester. The present invention relates to an aliphatic polyester thread suitable for a biodegradable fabric capable of suppressing seam shrinkage.

[0002]

2. Description of the Related Art Conventionally, aliphatic polyester fibers have been used mainly for industrial materials because of their excellent biodegradability, but they have not been specifically developed for clothing. It is. On the other hand, sewing threads made of polyester fibers made of an aromatic polyester such as polyethylene terephthalate are widely used for clothing. However, in the case of this aromatic polyester fiber, although it is a sewing thread excellent in Young's modulus and strength, there is a problem that the texture is coarse and hard, and the refractive index is high, so that the coloring property is poor and the seam shrinkage is large, Luster with a luxurious feeling is far away, and since it is not biodegradable and easily decomposed in the natural environment, it has a defect that it remains semi-permanently unless incinerated when disposed. In addition, sewing thread for clothing usually requires seam quality, dyeing properties, and sewing threads without sewing shrinkage.
A stitch sewn with a high shrinkage thread such as an aromatic polyester thread could not withstand the shrinkage of the thread, causing puckering and degrading the stitch quality of the fabric. .

[0003] In order to solve the above-mentioned problems, there has been a demand for the development of a sewing thread which satisfies the improvement of the seam quality and the coloring property.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to take advantage of the properties of aliphatic polyester fibers which are rich in luster and coloring, to suppress seam shrinkage, and to achieve seam quality. It is an object of the present invention to provide a sewing thread which is excellent in stiffness and can be easily decomposed in a natural environment.

[0005]

In order to solve the above-mentioned problems, the sewing thread of the present invention employs the following constitution. (1) In a sewing thread in which two or more multi-filament yarns subjected to a primary twist are drawn and twisted together, at least a part of the multi-filament yarn is an easily degradable aliphatic containing L-lactic acid as a main component. It is made of polyester fiber yarn, and both the lower twist coefficient and the upper twist coefficient are 6,000 or more.
A sewing thread characterized in that the thread has a weight of 20,000. (2) The sewing thread according to the above (1), wherein a relationship between a shrinkage ratio obtained by combining a dry heat shrinkage ratio and a boiling water shrinkage ratio satisfies the following expression.

-2.0 ≦ KS + FS (%) ≦ 5.0 (where KS: dry heat shrinkage (%), FS: boiling water shrinkage (%)) (3) The yarn constituting the sewing thread The sewing thread according to the above (1) or (2), wherein the strength reduction rate in soil is 10% to 50%.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the aliphatic polyester thread of the present invention will be described in detail.

[0008] The sewing thread according to the present invention is a multifilament thread that is subjected to priming, two or more multifilament threads are aligned and then twisted, and at least a part of the thread is mainly composed of L-lactic acid. And a readily degradable aliphatic polyester fiber yarn.

[0009] In order to express the excellent coloring property of the aliphatic polyester, both the lower twist coefficient and the upper twist coefficient are set to 6,000 to 20,000, so that the dry heat shrinkage and the boiling water shrinkage are reduced. The combined shrinkage rate is -2% to 5
%, The seam shrinkage is suppressed, and the seam quality is excellent. If the shrinkage exceeds 5%, the sewn fabric is forced to deform by the same amount as the shrinkage, resulting in seam shrinkage and loss of shape, which tends to significantly degrade the stitch quality.

The aliphatic polyester used in the present invention includes polylactic acid, poly-3-hydroxypropionate, poly-3-hydroxybutyrate, poly-3-hydroxybutyrate valerate and the like. Blends and modified products can also be used.

The thread constituting the sewing thread is composed of a synthetic fiber multifilament thread, and at least a part thereof is composed of an aliphatic polyester fiber thread. The composition of the sewing thread is 100% aliphatic polyester fiber thread or other material,
For example, a combination with a filament made of another polyester or a polyamide filament may be used. However, 100% use of the aliphatic polyester fiber yarn is the most preferable configuration.

The aliphatic polyester fiber yarn in the present invention has a refractive index of preferably 1.50 or less, more preferably 1.45 or less, in order to improve color developability. Further, when the melting point is lower than 130 ° C., the quality of the seam becomes extremely low, such as generation and remarkable reduction of fusion between the single yarns and melting defects during friction heating. The melting point of the polyester is preferably 130 ° C. or more,
0 ° C. or higher is more preferable, and 170 ° C. or higher is further preferable. Here, the melting point means a peak temperature of a melting peak obtained by DSC measurement.

The most desirable polymer as an aliphatic polyester from the viewpoint of physicochemical properties is a polyester containing L-lactic acid as a main component. Mainly containing L-lactic acid means that 60% by weight or more of the component is composed of L-lactic acid, and may be a polyester containing D-lactic acid in a range not exceeding 40% by weight. .

[0014] Polylactic acid can be produced by a two-stage lactide method in which lactide is once produced from lactic acid as a raw material, followed by ring-opening polymerization, or by direct dehydration condensation in a solvent using lactic acid as a raw material. Is known as a one-step direct polymerization method. Polylactic acid used in the present invention,
Polylactic acid obtained by any of the production methods may be used. In the case of polymers obtained by the lactide method,
Since the cyclic dimer contained in the polymer is vaporized at the time of melt spinning and causes thread spots, the content of the cyclic dimer contained in the polymer before the melt spinning is 0.1% by weight.
It is desirable to make the following. Further, in the case of the direct polymerization method, since there is substantially no problem caused by the cyclic dimer, it can be said that it is more preferable from the viewpoint of the spinning property.

The higher the average molecular weight of the polylactic acid, the better, usually at least 50,000, preferably at least 10
And more preferably 100,000 to 300,000. If the average molecular weight is lower than 50,000, the strength physical properties of the fiber are undesirably reduced.

The polylactic acid in the present invention may be a copolymerized polylactic acid obtained by copolymerizing other components having an ester-forming ability in addition to L-lactic acid and D-lactic acid. Examples of copolymerizable components include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid,
In addition to hydroxycarboxylic acids such as 6-hydroxycaproic acid, ethylene glycol, propylene glycol,
Compounds having a plurality of hydroxyl groups in a molecule such as butanediol, neopentyl glycol, polyethylene glycol, glycerin, pentaerythritol or derivatives thereof, adipic acid, sebacic acid, fumaric acid, terephthalic acid, isophthalic acid, 2,6 -Naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid, and other compounds containing a plurality of carboxylic acid groups in the molecule or derivatives thereof.

In order to reduce the melt viscosity of the aliphatic polyester, an aliphatic polyester polymer such as polycaprolactone, polybutylene succinate and polyethylene succinate can be used as an internal plasticizer or an external plasticizer. Further, inorganic fine particles and organic compounds as a matting agent, a deodorant, a flame retardant, a yarn friction reducing agent, an antioxidant, a coloring pigment and the like can be added to the aliphatic polyester as required.

As the melt spinning method of the aliphatic polyester fiber, spinning can be performed by using a known melt spinning apparatus. Not only the round cross section but also the cap holes for the corresponding irregular cross sections can be used. Profiled yarns can also be produced. For example, when obtaining a three-lobe fiber, a base having a T-shaped or Y-shaped base hole may be used.

In the present invention, the sewing thread composed of the aliphatic polyester fiber thread has a lower twist / first twist coefficient of 6,
000 to 20,000, preferably 8,000
More preferably, it is 0 to 16,000. When the lower twist or upper twist coefficient is less than 6,000, or a sewing thread constituted with a twist coefficient exceeding 20,000, thread breakage occurs during high-speed sewing and the stitch quality is reduced. The twist coefficient can be determined as appropriate depending on the fineness of the constituent filament yarns and the twist balance of the first twist / first twist. The method of calculating the twist coefficient is: twist coefficient (K) = twist number × √ (denier number).

The sewing thread of the present invention has a high gloss, a high color developing property, and a property of easily decomposing in a natural environment.
%, Which is an aliphatic polyester thread suitable for biodegradable fabrics. In addition, this sewing thread has a shrinkage ratio of -2% to 5%, which is a combination of dry heat shrinkage ratio and boiling water shrinkage ratio, suppresses seam shrinkage, suppresses seam deformation, is excellent in dyeability, and simultaneously improves seam quality. Can be done. In the present invention, for example, the ply twist / twist coefficient is 6,000 to 2
By setting it to 0000, preferably 8,000 to 16,000, the combined shrinkage of dry heat and shrinkage of boiling water can be set to -2% to 5%.

The aliphatic polyester fiber sewing thread in the present invention preferably has a fiber strength of 2.65 cN / dtex or more. If the strength is less than 2.65 cN / dtex, it is not preferable because thread breakage at the time of sewing or a decrease in product strength due to a decrease in seam quality and sewing tear strength is not preferred. The fiber strength is more preferably 3.1 cN / d
tex or more, most preferably 3.5 cN / dte
x or more. Here, the upper limit of the fiber strength is not specified, but a typical upper limit is 4.5 cN / dtex.

The elongation of the sewing thread made of the aliphatic polyester fiber of the present invention can be adjusted by setting the original yarn and the processing conditions so that the residual elongation is about 10 to 50%. It is preferable from the viewpoint of seam impact durability.

In the present invention, for example, a drawn yarn obtained under the following spinning conditions is used, and the twist coefficient is 8000 to 160.
By processing in the range of 00, a sewing thread having an elongation of 10 to 50% can be obtained.

A poly L-lactic acid chip having a melting point of 172 ° C. and a refractive index of 1.45 was dried for 48 hours in a vacuum dryer set at 60 ° C., and the dried chip was spun at a spinning temperature of 220 ° C.
At a spinning speed of 3,000 m / min.
An undrawn yarn of T-36F is obtained. The obtained undrawn yarn is drawn at a temperature of 80 ° C, a heat setting temperature of 115 ° C, and a draw ratio of 1.45.
Draw twice to obtain a drawn yarn of 84T-36F. The obtained polylactic acid filament has an 80.3 dtex / 36 filament and a strength of 3.0 cN / dtex. The filament yarn is twisted at 980 T / m in the S direction to obtain a lower twist yarn. Next, three lower twisted yarns are aligned and the upper twist is performed at 750 T / m in the Z direction using a normal twisting machine to obtain a yarn for sewing.

The sewing thread comprising the aliphatic polyester fiber of the present invention can be manufactured as follows. 980 T / m of aliphatic polyester filament yarn in S direction
Twisting to obtain a sub-twisted yarn. Next, the lower twisted yarn is
750T in the Z direction using a regular twisting machine
/ M to give a thread for sewing.

Next, the thread for sewing is wound around a bobbin for dyeing with a normal soft winder, and dyed at a temperature of 120 ° C. using a normal package dyeing machine. Next, after washing with hot water and water, dehydration and drying are performed, followed by rewinding with a normal corn winder to obtain a suture using 100% of the polylactic acid filament of the present invention.

The cross section of the fiber is not limited, and it is preferable to use gloss with a modified cross section or to reduce the weight by using hollow fibers. Similarly, the fineness is not limited, but fibers having a single-filament fineness of about 0.5 denier to about 10 denier are preferably used. Further, the total fineness of the sewing thread is preferably 22 to 500 Dtex.

The sewing thread of the present invention is used for sewing ordinary fabrics, but is particularly suitably used for clothing and the like made of aliphatic polyester fiber yarns. That is, since both the sewing thread and the fabric are made of biodegradable threads, they are both decomposed, have little effect on the environment, and have excellent coloring properties. Therefore, they are optimally used for dyeing products.

As described above, the use of the sewing thread of the present invention is most suitable as a sewing thread for a fabric which can be decomposed in a natural environment such as aliphatic polyester fiber, cotton, rayon and the like. As other uses, it can be suitably applied to a sewing thread for medical clothing.

[0030]

The present invention will be specifically described below with reference to examples.

The measured values in the examples and comparative examples were obtained by the following methods.

(1) Raw yarn strength (cN / dtex) and raw yarn elongation (%) According to a tensile test described in JIS-L-1073, it was measured using an Instron type tensile tester.

(2) Fineness of sewing thread Five samples of 90 m in length were collected using a normal measuring machine.
The weight was averaged.

Y (dtex) = 1.111 × denier (3) Suture breaking elongation (%) and suture breaking strength (kg) Instron type tensile tester according to the tensile test described in JIS-L-2511 Was measured at a test length of 25 cm and a tensile speed of 30 cm / min.

(4) Lower Twist / Fon Twist Coefficient The twist coefficient was defined as twist coefficient (K) = twist number × √ (denier number).

Here, T is the number of ply twists / twist twists (T /
m), K is the primary / twist coefficient, D is the thread fineness (dte
x).

(5) Actually Measured Twist Twist / Over Twist The number was measured 10 times with a test length of 25 cm using a normal twisting machine.
The average was calculated.

(6) Decrease in strength in soil The suture of the present invention is buried at a depth of 10 cm in the soil, the strength of the suture is measured every six months, and the suture before embedding in the soil is L
1. The sewing thread taken out of the soil was designated as L2. The strength reduction rate was calculated from the following equation.

Strength reduction ratio (L) = L2 / L1 (%) (7) Dry heat shrinkage ratio Measured according to JIS-L-1013, 8.18.2 scab shrinkage ratio (A) method.

(8) Boiling water shrinkage ratio 5.10 Hot water shrinkage ratio Measured in accordance with JIS standard L1090-1992 A method (skew shrinkage ratio).

Example 1 A poly L-lactic acid chip having a melting point of 172 ° C. and a refractive index of 1.45 was dried for 48 hours in a vacuum dryer set at 60 ° C., and the dried chip was spun at a spinning temperature of 220 ° C. C. at a spinning speed of 3,000 m / min to obtain an undrawn yarn of 122T-36F. The obtained undrawn yarn was drawn at a drawing temperature of 80 ° C., a heat setting temperature of 115 ° C., and a draw ratio of 1.45 to obtain a drawn yarn of 84T-36F. The obtained polylactic acid filament is 80.3 dtex
-36 filaments, strength was 3.0 cN / dtex. The filament yarn was twisted at 980 T / m in the S direction from a twist coefficient of 8500 to obtain a lower twist yarn. Next, three lower twisted yarns were aligned and the upper twist was performed in the Z direction at 750 T / m with a twist factor of 11000 using a normal twisting machine to obtain a yarn for sewing. [Example 2] Spinning and drawing were performed in the same manner as in Example 1 to obtain a drawn yarn of 80.6 dtex-36f.

The obtained polylactic acid filament yarn was twisted at 1485 T / m in the S direction from a twist coefficient of 13000 to obtain a lower twist yarn. Next, three lower twisted yarns are aligned.
Using a normal twisting machine, a twist of 857 T / m was performed in the Z direction with a twist factor of 13000 to obtain a thread for sewing.

Comparative Example 1 Polyester multifilament 81.3 dtex-36 filament was twisted at 850.
From 0, 980 T / m was twisted in the S direction to obtain a lower twisted yarn. Next, three lower twisted yarns are aligned and a twist coefficient of 8500
From above, 750 T / m was twisted in the Z direction to obtain a thread for sewing.

[Comparative Example 2] Polyester multifilament 81.3 dtex-36 filament was prepared with a twist coefficient of 130.
From 00, twisting was performed at 1485 T / m in the S direction to obtain a lower twisted yarn. Next, three lower twisted yarns are aligned and the twist coefficient is 130.
From 00, 867 T / m was first twisted in the Z direction to obtain a thread for sewing. Next, the thread for sewing was wound around a bobbin for dyeing with a normal soft winder, and dyed at a temperature of 120 ° C. using a package dyeing machine. Next, after washing with hot water and water, dehydration and drying were performed, and rewinding was performed with a normal cone winder to obtain a sewing thread. An aliphatic polyester filament thread and a polyester filament thread were obtained. The performance of the obtained suture was measured, and the results are shown in Table 1.
It was shown to.

Next, the thread for sewing was wound up on a bobbin for dyeing with an ordinary soft winder, and dyed at a temperature of 120 ° C. using an ordinary package dyeing machine.
Next, after washing with hot water and water, dehydration and drying were performed, followed by rewinding with a normal cone winder to obtain a sewing thread using 100% of the polylactic acid filament of the present invention. The performance of the obtained sewing thread was measured, and the results are shown in Table 1.

[0046]

[Table 1]

As apparent from Table 1, the shrinkage of the sewing threads of Examples 1 and 2 was 3.2%, 4.7%, which is the sum of the dry heat shrinkage and the boiling water shrinkage, and the shrinkage was suppressed. Because
It was visually confirmed that there was no seam shrinkage or shape loss of the seam of the polylactic acid fiber fabric. -Shrinkage rate during dry heat treatment
The ratio of 0.8% is as follows: when the heat treatment is performed, the sewing thread itself slightly expands spontaneously, thereby suppressing the seam shrinkage at the seam, preventing the shape from being lost, and having optimum characteristics as the sewing thread. However, in Comparative Examples 1 and 2, the combined shrinkage ratios of the dry heat shrinkage ratio and the boiling water shrinkage ratio were both high, and seam shrinkage and shape loss occurred.

In the embodiment, the rate of decrease in the strength of the sewing thread was 4
It is 7% and 40%, which proves that biodegradation is actually easily performed in the natural environment. On the other hand, in the comparative example, the shrinkage rate of the sewing thread was high, the shape could not be coped with the seam shrinkage at the seam, and the shape collapsed, and the seam quality was poor. In addition, in terms of biodegradability in soil, aromatic polyesters have extremely high durability in the natural environment and do not easily decompose in the natural environment. Therefore, they remain semi-permanently unless incinerated when disposed. .

[0049]

The sewing thread of the present invention has a luster when used as a sewing thread.
Excellent color developability. By setting the range of shrinkage, which is a combination of dry heat shrinkage and boiling water shrinkage, to -2% to 5%, seam shrinkage and shape loss can be solved, and seam quality can be improved. It is a globally friendly sewing thread because it can be easily decomposed in the natural environment by setting the strength reduction rate in soil at 10% to 50%.

Claims (3)

[Claims] An easily decomposable yarn comprising at least a part of L-lactic acid as a main component, wherein at least a part of the multifilament yarn is made of L-lactic acid as a main component in a multi-filament yarn which has been subjected to a primary twist and two or more yarns are aligned and then super-twisted. It is made of an aliphatic polyester fiber yarn, and both the lower twist coefficient and the upper twist coefficient are 6,
000 to 20,000. 2. The sewing thread according to claim 1, wherein a relationship between a shrinkage ratio of the dry heat shrinkage ratio and a boiling water shrinkage ratio satisfies the following expression. −2.0 ≦ KS + FS (%) ≦ 5.0 (where KS: dry heat shrinkage (%), FS: boiling water shrinkage (%)) 3. The sewing thread according to claim 1, wherein the strength reduction rate of the thread constituting the sewing thread in the soil is 10% to 50%.