JPH02139409A - High-shrinkable polyester fiber - Google Patents

Abstract

PURPOSE:To obtain the subject fiber having high strength and shrinkable, satisfying specific physical properties and suitable for packaging use, etc., by copolymerizing a specific amount of a 3rd component to ethylene terephthalate. CONSTITUTION:The objective fiber is a polyester fiber produced by copolymerizing 8-30mol% of a 3rd component (e.g., isophthalic acid or naphthalenedicarboxylic acid) to ethylene terephthalate and satisfying the formulas, i.e., intrinsic viscosity eta>=0.6,, strength S>=5g/de and boiling water shrinkage W>=25% at the same time, having a peak of a heat-stress curve at 70-160 deg.C and satisfying the formula R>=0.2g/de wherein R is thermal stress at 100 deg.C. The fiber can be produced by esterifying terephthalic acid with ethylene glycol to form terephthalic acid glycol este, etc., adding a prescribed amount of the 3rd component at an arbitrary stage in the above reaction and heating the reaction product under reduced pressure to effect polycondensation reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polyester fiber having high strength and high shrinkage.

[Prior Art] Polyester m1Iff has various excellent properties and is therefore widely used not only for clothing purposes but also for industrial purposes. In particular, its use in industrial applications is expanding year by year, and it is also used for special purposes. Although special physical properties are required depending on the application, polyester fibers used for ropes and strands generally require high strength, and few require high shrinkage performance. On the other hand, it is possible to impart high shrinkage performance to polyester fibers by using a polymer with a relatively low degree of polymerization, for example, as disclosed in JP-A-62-191511.
A method of winding at a speed of However, when this method is applied to polyester with a high η required for use in special applications, oriented crystallization tends to occur, and as oriented crystallization progresses, it is difficult to obtain high shrinkage properties. There is. Further, JP-A-63-196751 discloses a polyester having high shrinkage properties using a polyester copolymerized with isophthalic acid and made amorphous. However, JP-A-63-196751 @
The method disclosed in the publication uses a binder m suitable for nonwoven fabrics.
Since M is reduced, high strength and high shrinkage fibers cannot be obtained.

[Object of the Invention] An object of the present invention is to provide a polyester fiber with high strength and high shrinkage, and in particular to provide a yarn used for special purposes such as packaging.

[Structure of the invention] The present invention provides ethylene terephthalate containing 1 to 8 to 30 mol% of ethylene terephthalate.
A polynisder fiber copolymerized with a third component of
It satisfies the following 1) to 3) at the same time, has a peak in the temperature of 70 to 160°C in the thermal stress curve, and has a humidity of 7.
A highly shrinkable polyester fiber characterized by a thermal stress value at 00°C satisfying 4).

1) Intrinsic viscosity η: η≧06 2) Strength S: S≧5 g/de 3) Boiling water shrinkage rate: ≧25% 4) Thermal stress value R: R≧0.2 g/de.

The polymer constituting the highly shrinkable polyester fiber of the present invention has prephthalic acid as the main acid component, ethylene glycol as the main glycol component, and is further copolymerized with 8 to 30 mol% of a third component. Examples of the third component to be copolymerized include difunctional carboxylic acids such as isophthalic acid, naphthalene dicarboxylic acid, and adipic acid;
Examples include, but are not limited to, diol components such as neopentyl glycol, diethylene glycol, and propylene glycol.

If the copolymerization amount of this third component is less than 8 mol%, the high shrinkage properties that are the object of the present invention cannot be obtained, and if it exceeds 30 mol%, fusion of chips or melt-discharge may occur during the same phase polymerization of the culm during production. At times, there is a risk that the chip may not be properly engaged.

Further, the third component is not limited to one type, but can be used in combination of a plurality of types, and the total copolymerization amount may be 8 to 30 mol%. In addition, conventionally known catalysts, additives, and colorants may be included.

Next, the polyester fiber of the present invention has an intrinsic viscosity η≧0
It needs to be 6. When η is less than 0.6, the strength S
is 5 g/de or more and has high shrinkage.
m cannot be obtained. The higher the intrinsic viscosity η is, the more effective it is in developing strength, but if η exceeds 1.0, single filament breakage during melt discharge increases, which is unfavorable from the viewpoint of stringability.

The polyester fiber of the present invention can be obtained, for example, by the following method. That is, terephthalic acid and ethylene glycol, which are the main components, are directly esterified, a lower alkyl ester of terephthalic acid such as dimethyl terephthalate and ethylene glycol are transesterified, or terephthalic acid and ethylene glycol are transesterified. 1st step reaction and 1st step reaction product in which a predetermined amount of the third component is added at any stage of the reaction to produce glycol ester of terephthalic acid and/or its low polymer by reacting with oxide It is produced by a second stage reaction in which the polycondensate is heated under reduced pressure and subjected to a polycondensation reaction until a predetermined degree of polymerization is reached. Known catalysts are used in the first and second stage reactions, and additives and colorants may be used as necessary.

The degree of polymerization of the obtained copolyester has an intrinsic viscosity η of about 06 to 0.7, and solid phase polymerization can be used to further increase the degree of viscosity η. That is, a polyester having a desired η can be obtained by carrying out a solid phase polymerization reaction at a temperature of 170 to 210° C. for several hours under reduced pressure while stirring a polymer chip obtained by cutting the copolymerized polyester described above in a rotary dryer. can. The temperature of the bolysul is 260℃.
When melt spinning at ~330°C, the single fiber fineness after drawing is 1 to 20 de and the total de is 500 to 2000 de.
After being discharged, it is exposed to a heated atmosphere at a temperature above the melting point for delayed cooling, and then cooled and solidified with cooling air, and an oil agent is applied in an amount of 0.05 to 10% by weight. As the oil agent, a general oil agent for fibers can be used, and methods such as an oiling roller method, a spray method, etc. can be used as the application method. The undrawn yarn thus obtained may be passed through a take-off roller and wound into an undrawn package and stretched in a separate process, or it may be continuously stretched without being wound up after passing through the take-off roller. . The take-off speed of the undrawn yarn is preferably 1500 i/sin or less in order to prevent oriented crystallization. The stretching conditions are as follows:
After preheating at a temperature of 75 to 95°C, it is stretched in one stage to a stretching ratio according to the speed of the take-up roller, for example, 2.0 to 5.0 times, and then wound up, or it is further passed through heated gas and heated in air. A second stage of stretching is performed while heating at a temperature in the range of ~160°C, followed by winding. If the preheating temperature is lower than 10 DEG C., although a boiling water shrinkage rate of 25% or more can be given, stable yarn spinning is not possible, which is not preferable. Furthermore, when the temperature of the yarn exceeds 160°C due to heating, the stress at 100°C in the thermal stress curve does not exceed 0.2 g/de, and furthermore, the peak of thermal stress appears above 160°C. The desired high shrinkage performance cannot be achieved.

The polyester fibers of the present invention have a highly strained fiber structure as indicated by a specific thermal stress curve. That is, in the thermal stress curve, humidity 700
Thermal stress in °C is 0.2 g/de, preferably 0.25
g/de or more, and has physical properties having a thermal stress peak within a temperature range of 75 to 160°C.

Such physical properties are obtained as a result of imparting a fiber structure with large distortion through the spinning and drawing conditions as described above. Thermal stress at 700°C humidity is 0.2 g
If it is less than /de, the tightening force during heat treatment will be insufficient, and the boiling water shrinkage rate will be less than 25%, making it impossible to achieve the object of the present invention. Furthermore, if the temperature at which the peak of thermal stress appears is less than 75°C, distortion will be imparted near the glass transition of the polymer, resulting in poor spinning properties, and if the temperature at which the peak of thermal stress appears exceeds 160°C, Thermal stress around ℃ is small, and its value may be less than 0.2 a/de. In any case, the yarn of the invention cannot be obtained.

As explained above, the yarn of the present invention has high strength and high shrinkage, so it is useful as a wrapping material in addition to general industrial materials, and particularly as a tightening yarn for rolled hams. used.

[Example 1] Polyethylene terephthalate copolymerized with 20 mol % of isophthalic acid was synthesized by a conventional method to obtain a polymer having an intrinsic viscosity of 0.64. This polymer was cut into a size of approximately 2×2×3IllI and subjected to in-phase polymerization to obtain in-phase polymerized chips having three types of limiting viscosities η as shown in Table 7.

These three types of in-phase polymer chips were melted with an extruder and metered and discharged through a nozzle with 250 holes and a hole diameter of 0.55111 m so that the total de of the drawn yarn was about 1000 de. The discharged yarn passed through a heated atmosphere with a length of 300 mm and a temperature of 330°C provided under the nozzle, and then was heated at a relative humidity of 6 over a length of 300 Ilm.
5%, temperature 25% cold f! The J shoulder was cooled and solidified by blowing air. The cold fJJ solidified yarn was coated with an oil agent using an oiling roller, and then wound up as a package of undrawn yarn. The polymer temperature and take-up speed at the time of melting and discharge are also listed in Table-1.

After preheating the obtained undrawn yarn with a heated supply row, and performing the first drawing (magnification: DRl) with rollers,
Further, the yarn was wound in a second stage of stretching in a stretching gas bath to obtain a drawn yarn having a total denier of about 3000 de. Table 1 shows the physical properties of the drawn yarn thus obtained. In addition, NO, 5, 7 in the table
, 8 show comparative examples. Also, BWS in the table is humidity 700
It refers to the heat shrinkage rate at °C.

(Hereinafter, blank space) (Magnification: DR2) at a speed of 290 m/win [Example 2J Isophthalic acid (below) in the same manner as Example 1.

Chips in which the amount of the copolymer (referred to as IA) was varied within the range of 5 mol % to 30 mol % were melt-polymerized and then solid-phase polymerized to obtain in-phase polymer chips with an intrinsic viscosity η of about 0.75. Using this same phase polymerization chip, the take-up speed is 880 n+/wi
An undrawn yarn was obtained using the same method as in Example 1 with the polymer temperature shown in Table 2 and other conditions. A drawn yarn was obtained from this undrawn yarn in the same manner as in Example 1 under the conditions listed in Table 2. The physical properties of the obtained drawn yarn are not shown in Table 2, and in Table 4, No. 19 shows a comparative example.

(Hereinafter, blank space) [Example 3] A drawn yarn was obtained in the same manner as in Example 2, except that the third component in Example 2 was changed from isophthalic acid to neobenchi glycol (hereinafter, referred to as NPG). Table 3 shows the physical properties of the drawn yarn obtained. In the table, No. 014 indicates a comparative example.

As shown in the above examples, polyester mN with high strength and high shrinkage, which is the object of the present invention, was obtained.

Claims (1)

[Claims] A polyester fiber made by copolymerizing ethylene terephthalate with 8 to 30 mol% of a third component, comprising the following 1) to 3.
), and the humidity is 70 in the thermal stress curve.
A highly shrinkable polyester fiber having a peak at ~160°C and a thermal stress value at a temperature of 100°C satisfying 4). 1) Intrinsic viscosity η: η≧0.6 2) Strength S: 5≧5 g/de 3) Boiling water shrinkage W: W≧25% 4) Thermal stress value R: R≧0.2 g/de