JPH09291417A - Production of hot stretchable polyester fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for a hot stretchable polyester fiber capable of obtaining a cloth having a soft touch feeling after weaving or knitting, by carrying out a hot stretching treatment of a polyester-based un-non- stretching fiber under a specific condition, and also applicable to the production of hot stretchable fiber from other various lowly oriented non-stretching fibers. SOLUTION: This method for producing a hot stretchable polyester fiber is to heat-treat a polyester-based non-stretching fiber having >=45% ε0.2 structure uniformity parameter at >=Tg+50 deg.C, while stretching the same between a first roller 3 heated at (Tg+30) to (Tm-100) deg.C and a second roller 5 through a heater 4. The stretching ratio between the rollers 3, 5 is made as >=80% of that at break thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a heat-extensible polyester fiber, which has the property of being stretched by heating and can obtain a soft-textured fabric by knitting and weaving.

[0002]

2. Description of the Related Art Polyethylene terephthalate (PET)
Is widely used for clothing, industrial materials, and the like. Polyester fibers have high orientation and high crystallinity, and therefore have excellent properties such as firmness and stiffness, but have a drawback that the softness represented by softness and drape is slightly inferior.

As a method of imparting softness to a polyester fiber, there is a method of forming a heat-extensible fiber which is stretched by heat, and Japanese Patent Laid-Open No. 3-193948 discloses a method of heat-treating an undrawn yarn having a high polyester content and a low tension. After that, a method for producing by stretching at a low stretch ratio is disclosed.

However, this method uses a polyester highly oriented undrawn yarn obtained by high-speed spinning, and this method cannot be applied to a low oriented undrawn yarn. There are some yarns that cannot be made into highly oriented undrawn yarns, such as when copolymerized with other substances for imparting functionality to PET, and there is a problem that these yarns cannot be made into heat-extensible fibers. It was

[0005]

SUMMARY OF THE INVENTION It is a technical problem of the present invention to solve the above-mentioned problems and to provide a production method capable of producing a heat-extensible fiber by using various low orientation undrawn yarns. It is what

[0006]

The present inventors have arrived at the present invention as a result of intensive studies to solve the above-mentioned problems. That is, the present invention provides a polyester-based undrawn yarn having a structural integrity parameter (ε _0.2 ) of 45% or more with Tg
Tg + 50 between the first roller and the second roller while stretching is performed between the first roller and the second roller heated to +30 to Tm-100 ° C at a stretch ratio of 80% or more of the cutting stretch ratio of the unstretched yarn.
The gist is a method for producing a heat-extensible polyester fiber, which is characterized by heat treatment at a temperature of ℃ or more. However, Tg: glass transition temperature of undrawn yarn (° C) Tm: melting point of undrawn yarn (° C)

[0007] The structural integrity parameter (ε _0.2 ) referred to in the present invention represents the elongation when the yarn is treated in boiling water by applying a load, and is measured by the following method. . Using an ε-meter manufactured by Toyobo Engineering Co., a load of 0.2 g / denier is applied to the undrawn yarn having a length of 10 cm, and the yarn is treated in boiling water (about 98 ° C.) for 30 seconds. The length of the yarn before and after the treatment (the yarn after the treatment is immediately after pulling the yarn out of boiling water) is measured by applying the same load as above, and calculated by the following formula. ε _0.2 (%) = [(L ₁ −L ₀ ) / L ₀ ] × 100 where L ₀ : length before treatment (20 cm) L ₁ : length after treatment

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The polyester used in the present invention has ethylene terephthalate as a main repeating unit. However, in order to give a change in dyeing properties and hand, if it is about 5 mol% or less, isophthalic acid and 5-sodium are used as acid components. Aromatic dicarboxylic acids such as sulfoisophthalic acid,
Aliphatic dicarboxylic acids such as adipic acid and sebacic acid may be copolymerized with 1,4-butanediol, 1,9-nonanediol as an alcohol component.

In the present invention, it is necessary to use undrawn polyester yarn having a structural integrity parameter (ε _0.2 ) of 45% or more. Structural integrity parameter (ε _0.2 )
When the yarn having a content of less than 45% is subjected to a drawing heat treatment under the conditions of the present invention, only a yarn having a low thermal elongation is obtained, and such a yarn is mainly obtained by a high speed spinning method. However, the spinning equipment is limited, and it is difficult to use the staple fiber, which is not preferable. Although the upper limit of the structural integrity parameter (ε _0.2 ) of the undrawn yarn is not particularly limited, the structural integrity parameter (ε _{0.2
If 0.2} ) becomes too large, the yarn is likely to break during the drawing heat treatment, so it is preferable to set it to about 350%.

The structural integrity parameter (ε _0.2 )
In order to obtain a low orientation unstretched yarn of 45% or more, melt viscosity of polyester, spinning speed, etc. may be appropriately selected to perform melt spinning, but the method of selecting the spinning speed is the easiest. The spinning speed may be about 800-2500 m / min.

First, this low-oriented undrawn yarn is treated with Tg + 30 to Tm-
It is necessary to draw between the first roller and the second roller heated to 100 ° C. at a draw ratio of 80% or more of the cutting draw ratio of the undrawn yarn. If the temperature of the first roller is lower than Tg + 30 ° C., the molecular flow inside the fiber is not sufficiently promoted, so that the heat-expandable fiber cannot be obtained. On the other hand, when the temperature exceeds Tm-100 ° C, the temperature is too high, so that yarn breakage occurs or the fiber becomes inferior in quality.

When the draw ratio is less than 80% of the cut draw ratio of the unstretched yarn, the orientation of the fibers does not proceed, so that the yarn does not become a heat-stretched yarn or a yarn that is easily adhered. The upper limit of the draw ratio is not particularly limited, but if the draw ratio becomes too high, the undrawn yarn may be cut or the yarn may not be uniformly drawn. Therefore, it may be about 95% of the cut draw ratio. preferable.

Next, heat treatment is performed between the first roller and the second roller at a temperature of Tg + 50 ° C. or higher while performing the stretching as described above. If the heat treatment temperature is less than Tg + 50 ° C, the obtained fiber does not become a heat-extensible fiber, and when heat is applied in the post-processing, the fiber shrinks, so the fabric obtained by weaving and knitting has a hard texture. Will be things. The upper limit of the heat treatment temperature is not particularly limited, but if the heat treatment temperature is too high, the structure of the fiber is fixed by the heat treatment, and the yarn tends not to be thermally elongated in the subsequent step, so it is set to about Tm-30 ° C. It is preferable.

Such heat treatment may be carried out after stretching between the rollers, and further, if the heat treatment carried out after stretching is a relaxation heat treatment with a relaxation rate of 2% or more, the heat expansion of the obtained fiber is carried out. The rate can be higher. The relaxation rate is preferably 2 to 10%, and when the relaxation rate exceeds 10%, troubles such as yarn breakage due to winding around the roller occur, and fluffs and loops frequently occur, and post-processing steps such as weaving step. The passability in is likely to deteriorate. The upper limit of the relaxation heat treatment temperature is not particularly limited, but if the heat treatment temperature is too high, the structure of the fiber is fixed by the heat treatment, and the yarn tends not to be thermally elongated in the subsequent step, so Tm-30
It is preferable that the temperature be about ° C.

By the manufacturing method of the present invention, the boiling water shrinkage rate is −
About 1.0 to -5.0% of heat-extensible fiber can be obtained.

Next, the manufacturing method of the present invention will be described with reference to the drawings. 1 and 2 are schematic process diagrams showing an embodiment of the production method of the present invention. First, a description will be given based on FIG. The yarn Y unwound from the package 1
And is heated by the first roller 3 at Tg + 30 to Tm-100 ° C. Then, while being stretched between the first roller 3 and the second roller 5, it is heat-treated at a temperature of Tg + 50 ° C. or higher by the heater 4 installed between the first and second rollers and wound on the pan 6. When the heat treatment is performed after the stretching between the first roller 3 and the second roller 5, the heater 4 is provided between the second roller 5 and the pan 6.

Next, description will be made with reference to FIG. The yarn Y fed from the package 1 passes through the aligning roller 2 and is heated by the first roller 3 at Tg + 30 to Tm-100 ° C,
Stretching is performed between the stepped stretching roller 8 and a portion having a large diameter (corresponding to a second roller). Then, it is passed through the saddle-shaped heater 7 and guided to a portion having a small diameter of the stepped stretching roller 8 to perform relaxation heat treatment, and is wound around the pan 6.

[0018]

EXAMPLES Next, the present invention will be described in detail with reference to examples. The characteristic values in the examples were measured as described below. (1) Structural integrity parameter (ε _0.2 ) Measured by the method described above. (2) Shrinkage rate of boiling water Using ε meter manufactured by Toyobo Engineering Co., Ltd., sample length
The measurement was performed at 20 cm, a temperature of 98 ° C., a treatment time of 30 seconds, and a load of 0.001 g / denier. (3) Intrinsic viscosity [η] Equivalent mixture of phenol and ethane tetrachloride is used as a solvent at 20 ℃.
It was measured at. (4) Cutting draw ratio (elongation) of unstretched yarn Using Tensilon UTM-4-100 type manufactured by Oriental Co.,
It was measured at a sample length of 10 cm and a pulling speed of 10 cm / min. (5) Glass transition temperature (Tg), melting point (Tm) Using a differential scanning calorimeter DSC-7 type manufactured by Perkin Elmer Co.,
It was measured at a temperature rising rate of 10 ° C / min. (6) Feel (Soft feeling) A circular knitted fabric was circularly knitted using the obtained heat-expandable fiber, and treated under high pressure in water at 130 ° C for 1 hour.
The texture (softness) of the obtained knitted fabric was evaluated by 10 panelists on a 10-point scale by touching, and A to D based on the total score.
It was evaluated in four stages. A: 80 points or more Very soft B: 60 to 79 points Soft C: 40 to 59 points Slightly hard D: 39 points or less Hard

Examples 1 to 5 and Comparative Examples 1 to 5 PET having an intrinsic viscosity [η] of 0.69 was used in a conventional spinning machine,
At a spinning temperature of 295 ° C., the spinning speed was changed as shown in Table 1, and undrawn yarns having various structural integrity parameters (ε _0.2 ) were collected. At this time, using a spinneret with a spinning hole having a round cross section and a number of holes of 36, the discharge rate was adjusted so that the fineness after stretching was 75 denier. Table 1 shows the structural integrity parameter (ε _0.2 ) and the strength and elongation of the obtained undrawn yarn. The undrawn yarn had a Tg of 72 ° C and a Tm of 256 ° C.

Next, using the obtained undrawn yarn, according to the process shown in FIG. 1 or FIG. 2, drawn at a drawing speed of 400 m / min,
Heat treatment was performed. The temperature of the first roller, the draw ratio, the heat treatment temperature, and the relaxation rate during heat treatment were variously changed as shown in Table 2. Table 2 also shows boiling water shrinkage ratios of the obtained yarns.

[0021]

[Table 1]

[0022]

[Table 2]

As is clear from Table 2, according to the methods of Examples 1 to 5, fibers which are elongated by heat were obtained, and the cloths obtained by using these fibers had a soft texture. . On the other hand, in Comparative Example 2, the heat treatment temperature was too low, in Comparative Example 3, the heat treatment temperature at the time of stretching was too low, and in Comparative Example 4, the draw ratio was too low. The fabric obtained by using this fiber was poor in softness. In Comparative Example 1, since a highly oriented undrawn yarn having a small structural integrity parameter (ε _0.2 ) was used, a spinning machine and a winder for high speed spinning were required to obtain this undrawn yarn, and further, the obtained product was obtained. The fiber could be a heat-extended fiber, but the elongation rate was low.

[0024]

INDUSTRIAL APPLICABILITY According to the present invention, a heat-extensible fiber capable of obtaining a soft-textured fiber is obtained by knitting and weaving various low-oriented undrawn yarns and then subjecting them to heat treatment. It becomes possible.

[Brief description of drawings]

FIG. 1 is a schematic process drawing showing one embodiment of a production method of the present invention.

FIG. 2 is a schematic process chart showing another embodiment of the production method of the present invention.

[Explanation of symbols]

 1 Undrawn yarn cheese 2 Alignment roller 3 First roller 4 Heater 5 Second roller 6 Winder 7 Saddle-type heater 8 Stepped roller

Claims (3)

[Claims] 1. The structural integrity parameter (ε _0.2 ) is 45
% Or more of polyester unstretched yarn, Tg + 30 ~ Tm-100
Heat treatment at a temperature of Tg + 50 ° C or more between the first roller and the second roller while stretching between the first roller and the second roller heated to ℃ at a stretching ratio of 80% or more of the cutting and stretching ratio of the unstretched yarn. A method for producing a heat-extensible polyester fiber, which comprises: However, Tg: glass transition temperature of undrawn yarn (° C) Tm: melting point of undrawn yarn (° C) 2. The structural integrity parameter (ε _0.2 ) is 45.
% Or more of polyester unstretched yarn, Tg + 30 ~ Tm-100
Thermal stretching characterized by heat-treating at a temperature of Tg + 50 ° C or higher after stretching at a stretching ratio of 80% or more of the cutting and stretching ratio of the unstretched yarn between the first roller and the second roller heated to ℃ For producing water-soluble polyester fiber. However, Tg: glass transition temperature of undrawn yarn (° C) Tm: melting point of undrawn yarn (° C) 3. The method for producing a heat-extensible polyester fiber according to claim 2, wherein after stretching, a relaxation heat treatment of 2% or more is performed at a temperature of Tg + 50 ° C. or more.