JP2001032136A - Polyester fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester fiber containing propylene terephthalate as a main repeating unit, having dipropylene glycol content and intrinsic viscosity satisfying a specific formula, having high dyeability and excellent softness and elastic recovery and suitable for sportswear and inner wear. SOLUTION: The objective fiber contains propylene terephthalate as a main repeating unit and has a dipropylene glycol(DPG) content and intrinsic viscosity(IV) satisfying the formulas: 0.2<=DPG (mol%)<=7.0 and 0.7<=IV<=1.2. The fiber preferably satisfies the formula: 60<=ΔTc( deg.C)<=100 wherein ΔTc is the temperature difference between the temperature increasing crystallization peak temperature (Tc1) and the temperature decreasing crystallization peak temperature (Tc2) measured by a differential scanning calorimeter(DSC).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester fiber which has higher dyeability than conventional polypropylene terephthalate fibers, is soft, and has excellent flexibility and elastic recovery (stretchability). More specifically, the present invention can provide a polyester fiber having a high commercial value, which can be suitably used for sports clothing, inner clothing, and the like, and is suitable for applications such as blending and blending with other fibers.

[0002]

2. Description of the Related Art Polyester fibers typified by polyethylene terephthalate have excellent mechanical strength, chemical resistance and the like, and are therefore widely used mainly for clothing and industrial purposes. However, since polyethylene terephthalate fiber has a low elongation recovery rate and a low recovery rate, it has not been suitably used for applications requiring stretchability, such as innerwear, sports clothing, and pantyhose. Various proposals have been made to improve the stretchability.

One of the characteristics is that polypropylene terephthalate (commonly used polytrimethylene terephthalate) fibers using 1,3-propylene glycol instead of ethylene glycol can increase the elongation elastic recovery rate and the bending recovery rate. It is disclosed in, for example, JP-A-52-5320. However, this method can increase the elongation elastic recovery rate and the flexural recovery rate, but has insufficient dyeability, and cannot be dyed in a dark color at normal pressure.

[0004] Some fibers are known which have improved physical properties by copolymerizing other components with polypropylene terephthalate. For example, JP-A-58-31114 discloses a polyester obtained by copolymerizing or blending polyethylene terephthalate with polypropylene terephthalate at 3,500.
A method is disclosed in which a fiber is spun at a spinning speed of m / min or more, and further hot-drawn to obtain a fiber. Also, JP-A-11-128
No. 47, JP-A-11-61562 and the like disclose a method of using trimethylene glycol and ethylene glycol as glycol components or spinning a polyester obtained by copolymerizing a polyoxyalkylene glycol to obtain a fiber. . However, although such polyester fibers certainly show some improvement in dyeing properties, in all cases, the spinning properties become unstable due to a large decrease in melting point, making the handling difficult, and also obtained. Fibers have low strength and low elastic recovery, and only poor performance can be obtained.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a polyester fiber having good spinnability, high dyeability as compared with conventional polypropylene terephthalate fiber, softness, and excellent flexibility and elastic recovery (stretchability). Is to provide.

[0006]

In order to solve the above-mentioned problems, the main repeating unit is propylene terephthalate, and the content of dipropylene glycol (hereinafter, referred to as DPG) and the intrinsic viscosity (hereinafter, referred to as IV) are represented by the following formula (1). ) And (2).

[0007] 0.2 ≦ DPG (mol%) ≦ 7.0 (1) 0.7 ≦ IV ≦ 1.2 (2) It should be noted that the DPG referred to herein has the following structural formula.

HO—CH ₂ CH ₂ CH ₂ —O—CH ₂ CH ₂ CH ₂ —OH

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted intensive studies on factors for realizing high dyeing while maintaining good softness, flexibility and elastic recovery, and found that polyalkylene glycol and ethylene glycol were simply used. It has been found that simply copolymerizing the above-mentioned compounds not only makes the spinnability unstable due to a large decrease in the melting point, but also greatly reduces the strength and elastic recovery of the obtained fiber. From this viewpoint, as a result of examining polyester fibers having high dyeing properties and excellent strength and elastic recovery, it is extremely effective to contain a specific amount of DPG, a compound similar to 1,3-propanediol. Was found. Furthermore, by using a polyester fiber having a specific IV together with the DPG content, a polyester fiber that is soft, has excellent flexibility and elastic recovery rate, and has high dyeing properties can be obtained in a stable thread-forming state.

The polyester fiber of the present invention is a fiber whose main repeating unit is propylene terephthalate and which is composed of a polyester having a specific DPG content and IV.

The polyester of the present invention comprising propylene terephthalate as a main constituent unit has terephthalic acid or a derivative thereof as an acid component, and 1,1-propanediol, 1,1 as a glycol component.
2-propanediol, 2,2-propanediol,
1,3-propanediol can be mentioned. Among these glycol components, 1,3-propanediol is preferred from the viewpoints of stretchability and dyeability of the obtained fiber. Further, the unit of propylene terephthalate in the polyester constituting the fiber is preferably at least 80 mol%, more preferably at least 90 mol%, from the viewpoint of stretchability and the like.

The DPG content in the polyester fiber of the present invention must satisfy the following expression (1).

0.2 ≦ DPG (mol%) ≦ 7.0 (1) If DPG is less than 0.2 mol%, the dyeability is insufficient.
When DPG exceeds 7.0 mol%, not only a soft hand cannot be obtained, but also the elastic recovery rate tends to decrease and the strength tends to decrease. From such a viewpoint, the DPG content is preferably in the range of 0.5 ≦ DPG (mol%) ≦ 5.0, and more preferably in the range of 0.8 ≦ DPG (mol%) ≦ 4.0.

It is necessary that the IV of the polyester fiber satisfies the following expression (2).

0.7 ≦ IV ≦ 1.2 (2) If the IV of the polyester fiber is less than 0.7, the melt viscosity is low, and the fiber forming ability is poor. Is not satisfactory due to low strength. on the other hand,
When the IV exceeds 1.2, the melt viscosity is high, so that the metering with a gear pump is not performed smoothly, and the spinning property is deteriorated because it cannot be extruded stably. When the Young's modulus of the polyester fiber exceeds 35 g / d, the softness of the texture, which is a feature of the present invention, is lost. Therefore, the polyester fiber is preferably 20 to 30 g / d. Further, if the elastic recovery at 10% elongation is less than 85%, the stretchability is lacking. Preferably it is 95% or more.

The polyester fiber of the present invention has a temperature difference (hereinafter referred to as ΔTc) between a temperature rise crystallization peak temperature (Tc1) and a cooling crystallization peak temperature (Tc2) measured by a differential scanning calorimeter (hereinafter referred to as DSC). ) Is preferably in a specific range.

If the ΔTc of the polyester fiber exceeds the above range, the feeling, elastic recovery and dyeability may be poor.

The polyester fiber of the present invention is a polyester comprising propylene terephthalate as a main constituent unit and a fiber comprising DPG-containing polyester. In addition to the dicarboxylic acid component and glycol component constituting the polyester, the polyester fiber is dyed. Other components can be further copolymerized to improve the properties and texture. Examples of the dicarboxylic acid component and glycol component to be copolymerized include acid components such as aromatic dicarboxylic acid, aliphatic dicarboxylic acid and alicyclic dicarboxylic acid, and glycol components such as aromatic glycol, aliphatic glycol and alicyclic glycol. Can be mentioned.

The above-mentioned dicarboxylic acid component, glycol component and the like may be used alone or in combination of two or more. The amount of the copolymer component is preferably 20 mol% or less, more preferably 10 mol% or less, in view of mechanical properties such as strength of the obtained fiber, dyeability, elastic recovery and the like.

The polyester constituting the polyester fiber in the present invention is obtained by the following method. For example, (1) polyester is produced by transesterification of dimethyl ester of carboxylic acid with glycol and subsequent polycondensation reaction, and (2) polyester is produced by esterification reaction of dicarboxylic acid and glycol and subsequent polycondensation reaction. In a conventional method, DPG can be obtained by adding DPG at any stage of the polyester reaction step and incorporating it into the polyester.

The catalyst used for the polyester reaction is as follows:
A general reaction catalyst for producing a polyester can be used. For example, esterification and transesterification catalysts include alkaline earth metals, zinc, manganese,
As a metal compound such as cobalt and titanium, and a polycondensation reaction catalyst, antimony, titanium, and germanium compounds can be used.

The polyester fiber of the present invention may be a pigment such as titanium oxide or carbon black, a surfactant such as an alkylbenzene sulfonate, a conventionally known antioxidant, or a coloring inhibitor as long as the object of the present invention is not impaired. , A light stabilizer, an antistatic agent and the like.

The polyester fiber in the present invention can be produced by a conventionally known method. For example, 500
A method of melt-spinning at a speed of 次 い で 2500 m / min, followed by drawing and heat treatment, a method of melt-spinning at a speed of 1500 to 5000 m / min, and simultaneously performing drawing and false twisting, or performing drawing and false twisting, Any spinning conditions such as a method of spinning at a high speed of 5000 m / min or more and omitting a stretching step depending on the application can be adopted.

The cross-sectional shape of the polyester fiber of the present invention is not limited to a circle, but may be a triangular, flat, multi-lobe, polygonal, H-shaped, or Π-shaped cross-section. Further, the filamentous form of the fiber,
Either filament or staple may be used, and is appropriately selected depending on the application.

The polyester fiber of the present invention can be used in the form of a fabric, such as a woven fabric, a knitted fabric, or a non-woven fabric, depending on its use.

The polyester fiber of the present invention can be obtained, for example, by the following method. Using dimethyl terephthalate and 1,3-propanediol, using a titanium compound and an alkali metal compound in combination as a transesterification reaction catalyst, heating the mixture for 4 hours with stirring to 140 to 230 ° C., and terminating the transesterification reaction; A phosphorus compound is used as a coloring inhibitor. Next, a DPG and a titanium compound as a polymerization catalyst are added, and a polycondensation reaction is carried out at a temperature of 250 ° C. under reduced pressure to obtain an intrinsic viscosity of 1.0 or more and a DPG content of 0.1.
More than 2 mol% of polymer is obtained.

After the chips thus obtained are dried, the melt diameter is adjusted by a usual melt spinning method at a spinning temperature of 260 ° C. to a pore diameter of 0.3 mm.
Spinning speed 500m /
Spin for more than a minute to get undrawn. The obtained undrawn yarn is drawn using a usual hot roll drawing machine to obtain a drawn yarn of 75 denier and 24 filaments.

[0028]

The present invention will be described in more detail with reference to the following examples. In addition, each characteristic value in an Example was calculated | required by the following method. A. IV Orthochlorophenol (hereinafter OC) at a temperature of 25 ° C
0.8 g of a sample is dissolved in 10 ml of P), and the relative viscosity (ηr) is obtained from the following equation using an Ostwald viscometer, and IV is calculated.

Ηr = η / η₀= (T × d) / (t₀× d₀) IV = 0.0242ηr + 0.2634 η: viscosity of polymer solution η₀: Viscosity of OCP t: falling time of solution (sec) d: density of solution (g / cm)^Three) T₀: Fall time of OCP (second)  d₀: Density of OCP (g / cm^ThreeB.). Quantification of DPG Using VARIAN UNITYINOVA600
hand,¹H-NMR is measured, and the integral ratio of the obtained signal is measured.
Quantified from C. ΔTc (° C.) by DSC Using DSC (PerkinElmer DSC7 type)
A thermogram was obtained by the measurement method described in. polyester
10 mg of fiber is pre-treated at 280 ° C for 5 minutes
It was cooled and heated up to 280 ° C at a heating rate of 16 ° C / min.
Thereafter, the temperature was immediately lowered at a rate of 16 ° C./min. During the heating
Onset crystallization peak temperature and onset recrystallization during cooling
PerkinElmer data source for crystallization peak temperature
ΔTc (° C.) was determined using a physical system. D. Young's modulus, strength, elongation Using a Tensilon tensile tester manufactured by Toyo Baldwin
With a test length of 20 cm and a tensile speed of 10 cm / min.
-The value was determined from the distortion curve. E. FIG. Elongational elastic recovery rate The sample was measured using a constant-speed
20c with initial load of 1 / 30g per neal
m, and set the pulling speed to 1
Stretch to a predetermined elongation to 0%. Immediately, the same speed
Weight, and from the recorded stress-strain curve to the specified elongation.
Constant elongation at α, reduced until stress equals initial load
Assuming that the recovered elongation is β, it can be obtained by the following equation.

Elongation elastic recovery (%) = β / α × 100 Texture The softness was determined by a sensory evaluation in five stages. The case where these were the best was evaluated as grade 5, and the case where they were the worst was evaluated as grade 1. (Grade 3 or higher is passed.) Evaluation of Dyeing Property Two polyester fibers obtained were drawn and aligned to prepare a 24-gauge jersey cylinder, and a treatment bath containing 1 g / l of "Sundet" G-29 (manufactured by Sanyo Chemical Co., Ltd.) and 1 g / l of soda ash. In the course of scouring, a dyed sample fabric was obtained. Further, the dyed sample fabric was prepared by adding 0.3 g / l of Sun Salt and Resorin Blue FB.
Dyeing was performed in a bath of L 0.2 g / l at 110 ° C. for 60 minutes (bath ratio 1: 100). After cooling, the knitted fabric was taken out, soaped, washed and air-dried, and the dye exhaustion was determined by the following formula. The higher the dye exhaustion rate, the better the dyeability.

Dye exhaustion rate = (617.2 of dye solution before dyeing)
(absorbance at nm-617.2 nm absorbance of dye solution after dyeing) /617.2 nm absorbance of dye solution before dyeing × 100 Example 1 95 parts by weight of dimethyl terephthalate, 75 parts by weight of 1,3-propanediol and ester As an exchange reaction catalyst, tetrabutyl titanate (hereinafter referred to as TBT) 0.02
Parts by weight, lithium acetate dihydrate (hereinafter referred to as LAH)
Using 0.02 parts by weight, the temperature was raised over 4 hours while stirring to 140 to 230 ° C. to terminate the transesterification reaction,
0.005 parts by weight of phosphoric acid was added as a coloring inhibitor.
Then, 1.85 parts by weight of DPG and 0.10 parts by weight of TBT were added, and a polycondensation reaction was carried out at a temperature of 250 ° C. under reduced pressure to obtain a polymer. The IV of this polymer is 1.12
And the DPG content was 2.3 mol%. Next, after drying the obtained polymer, spinning is performed at a spinning temperature of 260 ° C. and a spinneret having a hole diameter of 0.3 mmφ × 24 holes at a spinning take-off speed of 1800 m / min by a normal melt spinning method.
Unstretched was obtained. The obtained undrawn yarn was drawn at a temperature of 1 HR at 60 ° C., at a temperature of 2 HR at 90 ° C. and a draw ratio of 3.1 times using a usual hot roll drawing machine to obtain a drawn yarn of 75 denier and 24 filaments. The properties and results of the obtained fibers are shown in Table 1. The dye exhaustion rate was 79%, and the soft feeling was good. Comparative Examples 1 to 3 Comparative Example 1 is the same as Example 1 except that DPG is not added, and Comparative Examples 2 and 3 are the same as Example 1 except that the amount of DPG added is changed. Polymers and fibers were obtained. The properties of the obtained fiber are shown in Table 1. Comparative Example 1 was inferior in dyeability. Further, Comparative Examples 2 and 3 each had a low elongation elastic recovery property, and the yarn shrank and became hard, resulting in poor softness. Examples 2 to 6 Polymers and fibers were obtained in the same manner as in Example 1 except that the amount of DPG was changed. The properties of the obtained polyester fiber are shown in Table 1. The fibers obtained in Examples 2 to 9 have good dyeing properties and stretch elastic recovery properties,
The soft feeling was also good. Comparative Examples 4 and 5 Fibers were obtained in the same manner as in Example 1 except that the IV of the polymer was changed. The properties of the obtained polyester fiber are shown in Table 1. In Comparative Example 4, the spinnability was unstable, and the obtained fiber had many fluffs and low strength. Comparative Example 5 was inferior not only in the dyeability but also in the softness. Examples 7 and 8 In Example 7, 0.05 parts by weight of TBT and 0.05 parts by weight of antimony trioxide were used as polymerization catalysts.
A polyester fiber was obtained in the same manner as in Example 1 except that 0.05 parts by weight of BT and 0.05 parts by weight of germanium oxide were used. Table 1 shows the properties of the obtained fibers. Examples 7 and 8 satisfying the scope of the present invention have good dyeing properties,
It had stretch elastic recovery characteristics and had a good soft feeling.

[0032]

[Table 1]

[0033]

The fiber obtained by the present invention has higher dyeability than conventional polypropylene terephthalate fiber, is soft and has excellent flexibility and elastic recovery (stretchability), and is therefore suitable for sports clothing, inner clothing and the like. It is suitable for applications such as blending and blending with other fibers.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 CF051 GK01 4L035 AA09 BB33 BB89 BB91 EE01 EE08 EE20 HH10

Claims (2)

[Claims] A polyester fiber whose main repeating unit is propylene terephthalate and whose dipropylene glycol (DPG) content and intrinsic viscosity (IV) satisfy the following formulas (1) and (2). 0.2 ≦ DPG (mol%) ≦ 7.0 (1) 0.7 ≦ IV ≦ 1.2 (2) 2. The temperature difference (ΔTc) between the temperature-rise crystallization peak temperature (Tc1) and the cooling crystallization peak temperature (Tc2) measured by a differential scanning calorimeter (DSC) satisfies the following equation (3). The polyester fiber according to claim 1, wherein 60 ≦ ΔTc (° C.) ≦ 100 (3)