JP2682141B2 - High-strength modified polyester fiber and seat belt made of the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a modified polyester fiber having a high strength and capable of dyeing a basic dye. More specifically, the present invention relates to a modified dye dyeable with a basic dye. The present invention relates to a high-strength basic dye dyeable modified polyester fiber which is useful for seat belts, canvases and the like for which polyester fiber has not been used.

[Prior Art] Polyester (particularly polyethylene terephthalate) fibers have excellent mechanical properties such as high strength and high modulus, good dimensional stability, and excellent durability such as weather resistance. Widely used for various purposes. For such industrial applications, unmodified polyester (homopolyester) fibers, which are advantageous in terms of mechanical properties, are usually used, and particularly high strength and high toughness polyester fibers are used for seat belts.

[Problems to be Solved by the Invention] However, in recent years, consumers' tastes have been diversified, and there has been a strong demand for fashionable industrial materials such as seat belts. Compared with homopolyester fibers to meet such demands, dyeing and coloring properties of basic polyester dyeable modified polyester fibers, etc. are used, and by using these materials, different colors (multicolor) and It is considered to express a moku tone.

However, the conventional basic dye-dyed modified polyester fiber, which is said to have high strength, has a strength of at most 4.5 g / d, which is insufficient as an industrial material.

In response to the recent demand for fashionable industrial fibers,
If it is attempted to obtain a color pattern using only conventional non-modified polyester fibers, it is necessary to use dyed yarn, which increases the cost. A method in which polyester fibers and nylon fibers are interwoven is also conceivable, but it cannot be used as a seat belt because of its low strength and initial tensile elastic modulus. Further, when the polyester fiber is mixed with a known basic dye-dyeable modified polyester fiber, the strength of the basic dye-dyeable polyester fiber is low, and a seat belt satisfying the mechanical properties cannot be obtained.

The object of the present invention is to solve the above problems and to improve the strength as an industrial fiber for dyeing seat belts, canvas, etc., which satisfies the necessary strength and initial tensile modulus and is rich in fashionability. To provide polyester fibers.

[Means for Solving the Problems] The above-mentioned object of the present invention is a modified polyester fiber obtained by copolymerizing an isophthalic acid component containing 1.1 to 1.9 mol% of a metal sulfonate group, wherein the intrinsic viscosity [η] is A high-strength modified polyester fiber characterized by having a stretched yarn strength of 0.65 or more, a drawn yarn strength of 6.0 g / d or more, and a temperature dependence coefficient (K _T ) of the dyeing amount shown by the following formula of 2.0% / ° C or less Can be achieved.

The present invention will be described in more detail below.

The modified polyester of the present invention comprises ethylene terephthalate as a main repeating unit and an isophthalic acid component containing a metal sulfonate group (hereinafter referred to as S component) of 1.1 to 1.9.
It is a polyester copolymerized by mol%.

If the S component content is less than 1.1 mol%, satisfactory dyeability cannot be obtained even if the dyeing temperature is increased. On the other hand, when the content of the S component exceeds 1.9 mol%, the melt viscosity is remarkably increased due to the thickening effect of the S component, and the desired high-strength polyester fiber cannot be obtained. From this point of view, S
The content of the component is preferably 1.3 to 1.8 mol%.

In the present invention, the isophthalic acid component (S component) containing a metal sulfonate group is a compound represented by the following formula, specifically, dimethyl (5-sodium sulfo) isophthalate, bis-2-hydroxyethyl (5 -Sodium sulfo) isophthalate, bis-4-hydroxybutyl (5-sodium sulfo) isophthalate and the like.

(However, M is an alkali metal such as Na, Li, K, A,
A 'is -CH ₃ or - indicates a (CH _{2) n} OH. _n represents an integer of 2 or more. ) Preferred isophthalate components containing a metal sulfonate group include dimethyl (5-sodium sulfo) isophthalate and bis-2-hydroxyethyl (5-sodium sulfo) isophthalate.

Further, the polyester of the present invention is preferably copolymerized with a glycol component in addition to the isophthalic acid component. By copolymerizing the glycol component, the melt viscosity of the polymer can be lowered, which is advantageous for increasing the strength. Further, since the amorphous portion is increased, the dyeability is also improved.

The molecular weight range of the preferred glycol component is 400-6000
The one having a molecular weight of less than 400 has a small effect of improving the dyeability, and due to the low boiling point of glycol, glycol is scattered out of the system during the polycondensation reaction to make the copolymerization amount constant. Becomes difficult. On the other hand, a glycol component having a molecular weight of more than 6000 deteriorates the oxidative decomposition resistance of the copolymerized polymer and makes it difficult to uniformly copolymerize the glycol component.

The molecular weight of the glycol component is more preferably 400 to 2000, particularly preferably 400 to 1000.

Typical examples of the glycol component having a molecular weight of 400 to 6000 include polyalkylene glycol represented by the following formula.

A (C _n H _2n O) _m H (A is C _l H _{2l + 1} O or OH, _l is 1 to 10, _n is 2 to 5, _m
Is 3 to 100) As the polyalkylene glycol, polyethylene glycol having OH groups at both ends is more preferable.

The copolymerization amount of the glycol component is preferably in the range of 0.5 to 1.9% by weight based on the obtained polyester. If it is less than this range, the effect of improving the dyeability becomes small, and if it is more than this range, the weathering fastness and oxidative decomposition resistance of the dyed product are greatly reduced. Therefore, the copolymerization amount of the glycol component is more preferably 0.7 to 1.5% by weight.

In addition to the copolymerization component, a normal transesterification catalyst,
It may contain a polymerization catalyst, a side reaction inhibitor such as a phosphorus compound or an alkali metal salt, a matting agent such as titanium dioxide, a coloring inhibitor, and an oxidative decomposition inhibitor.

In particular, the alkali metal salt has an effect of suppressing the amount of diethylene glycol as a by-product, and the oxidative decomposition inhibitor has an effect of suppressing deterioration of oxidative degradability of the polymer due to glycol copolymerization,
It is preferred to use. Further, it is preferable to contain a weathering agent such as an ultraviolet absorber.

The modified polyester fiber of the present invention has an intrinsic viscosity [η] of 0.
Must be 65 or higher. When the intrinsic viscosity is less than 0.65, the degree of polymerization is low, so the durability of the yarn is low, and the life required as a seat belt is not particularly satisfied. For this reason, the intrinsic viscosity of the modified polyester fiber of the present invention is more preferably 0.70 or more.

Further, the strength of the modified polyester fiber of the present invention needs to be 6.0 g / d or more. For strength less than 6.0g / d, for industrial use,
In particular, it does not meet the mechanical properties required as fibers for seat belts. Therefore, the strength of the modified polyester fiber of the present invention is more preferably 7.0 g / d or more, and further, 8.
It is particularly preferably 0 g / d or more.

The temperature dependence coefficient (K _T ) of the dyeing amount of the modified polyester fiber of the present invention needs to be 2.0% / ° C. or less. Where K
_T is expressed by the following equation, and is a parameter indicating that the greater the value, the greater the change in the amount of dyeing due to the temperature change.

When K _T exceeds 2.0, the change in dyeing rate due to the change in dyeing temperature in the dyeing process becomes too large. For example, in the dyeing process such as seat belts that are heat-set after being placed in a dye bath, uneven dyeing increases and it cannot be used as a product, so considering industrial production, K _T needs to be 2.0 or less, 1.7 or less. Is more preferable.

Further, the degree of amorphous orientation π of the modified polyester fiber of the present invention
It is preferable that a is 0.52 to 0.85. Where πa is 0.
When it is less than 52, the initial tensile elastic modulus of the obtained fiber is low and only a belt having a low modulus can be obtained when used as a seat belt. Furthermore, the temperature dependency coefficient K _T of the dyeing amount of the fiber is 2.0.
It tends to be higher than [% / ° C]. Therefore, the degree of amorphous orientation of the drawn yarn is preferably 0.52 or more. Further, when the degree of amorphous orientation exceeds 0.85, the fibers are likely to be fibrillated, the number of yarn breakage during twisting is increased, and the durability is lowered.Therefore, the degree of amorphous orientation of the drawn yarn should be 0.85 or less. preferable.

In addition, since the amorphous orientation degree of the drawn yarn can be increased by using a hot plate having a temperature gradient during drawing, the temperature dependency coefficient K _T of the dyeing amount can be 2.0% / ° C or less. it can.

As described above, the polyester fiber of the present invention is not only dyeable with a basic dye, but also has durability, high strength, and stable dyeability, so that a basic dye dyeable polyester fiber could not be conventionally developed. It can be deployed for industrial use for the first time. Especially when it is used for seat belts, its effect is exhibited. When used for a seat belt, it is preferable to interweave the fiber of the present invention with a fiber having different dyeability, because a pattern and a moku tone can be expressed. The fiber different in dyeability from the fiber of the present invention refers to a fiber that is non-staining with a basic dye, and particularly, the third fiber.
Polyester fibers having no copolymerized components are preferred.
Here, polyethylene terephthalate which is not copolymerized with the third component is preferably ordinary polyethylene terephthalate,
It may be included without departing from the object of the present invention. When weaving, the weaving ratio (homopolyester fiber / high-strength modified polyester fiber of the present invention) is preferably 30/70 to 98/2, and more preferably 50/50 to 90/10.

The high-strength modified polyester fiber of the present invention can be specifically produced, for example, as follows.

Isophthalic acid component containing 1.1 to 1.9 mol% of metal sulfonate group, more preferably polyethylene terephthalate copolymerized with 0.5 to 1.9 wt% of polyalkylene glycol, having an intrinsic viscosity of about 0.5 to 0.6 by melt polymerization reaction. After obtaining, the intrinsic viscosity of the polymer is increased to 0.80 or more by solid-state polymerization reaction. At this time, the solid phase polymerization time is 30
It is preferable that the time is less than or equal to the time from the viewpoint of yarn-forming property and yarn physical property.
Here, when the intrinsic viscosity of the polymer is less than 0.80, the intrinsic viscosity decreases due to thermal decomposition / hydrolysis during spinning, and the intrinsic viscosity of the fiber becomes less than 0.65. Therefore, the intrinsic viscosity of the polymer is 0.80 or more.

The polymer thus obtained is spun using an extruder type spinning machine at a spinning temperature of 290 to 310 ° C., and a heating cylinder having a temperature of 250 to 350 ° C. and a length of 100 to 300 mm is attached under the spinneret and gradually cooled. Subsequently, the yarn is cooled using a chimney style, and is drawn or continuously drawn. At this time, it is preferable to carry out spinning under the conditions satisfying the following respective formulas, since the Wooster spots are small and the strength can be enhanced.

Apparent viscosity ηa ≦ 10 ⁴ [poise] Shear rate ≦ 3000 [sec ⁻¹ ] The shear rate is more preferably 1000 to 2000 [sec ⁻¹ ].

The undrawn yarn obtained as described above is drawn using a hot plate having a temperature gradient from the inlet side to the outlet side. Since stable drawing is difficult with ordinary hot roll drawing and many yarn breakages and fluffs occur, a hot plate having a temperature gradient is used.

[Examples] The polyester fiber of the present invention will be specifically described below with reference to Examples. The physical properties in the examples were measured by the following methods.

(Intrinsic viscosity [η]) Orthochlorophenol was measured at 25 ° C.

(Dyeing amount (dyeability)) 5% ow of malachite green oxalate (trade name, manufactured by Kanto Chemical Co., Inc.) was used for a tubular knitted fabric obtained from fibers to be evaluated.
f, Dyeing is performed for 60 minutes in a hot aqueous solution of 0.5 g / acetic acid and 0.5 cc / sodium acetate at a constant temperature (dyeing temperature) at a bath ratio of 1: 100. Then, determine the dye exhaustion rate of the tubular knitted fabric by measuring the dye concentration in the dyeing residual liquid after pulling up the tubular knitted fabric,
This is defined as the dyed amount (dyeability).

(Fiber strength / elongation) Fiber strength / elongation is in a standard state test room, and a constant-speed extension type universal tensile tester TENSILON manufactured by Toyo Baldwin Co., Ltd.
It was measured using UTM-III.

However, the measurement conditions are 5kg f tension type load cell,
Gripping interval 25 cm, pulling speed 30 cm / min, recording paper feed speed 5
It was set to 0 cm / min.

(Amorphous orientation degree πa) The amorphous orientation degree of the fiber was calculated by the following formula by measuring the fiber density ρ [g / cm ³ ] and the birefringence Δn.

Here, Δn: Birefringence measured by compensator method Δnc: Intrinsic birefringence of crystal (0.212) Δna: Intrinsic birefringence of completely amorphous (0.199) πc: Crystal orientation determined by wide-angle X-ray scattering method χc: Crystallinity ρ: Density measured by the density gradient tube method using n-heptane / carbon tetrachloride in light / heavy liquid [g / cm ³ ] ρa: Completely amorphous density 1.335 [g / cm ³ ] ρc: Crystalline density 1.455 [g / cm ^3] temperature dependence coefficient dyeing amount (temperature dependence coefficient K _T dyeing amount) KT [% / ℃] is dyeing temperature 110
The amount of dyeing at C and 130 C (M ₁₁₀ and M ₁₃₀ , respectively) was measured and calculated by the following formula.

Example 1 150 kg of dimethyl terephthalate, 9 ethylene glycol
4kg, lithium acetate dihydrate 210g, manganese acetate tetrahydrate 30
g, antimony trioxide 60g in a mixture of dimethyl (5-sodium sulfo) isophthalate 4kg (1.7mol% copolymerization)
Was added to carry out a transesterification reaction. Next, trimethyl phosphate 64.5 g, ethylene glycol slurry containing titanium dioxide 16% by weight 810 g, and the decomposition inhibitor Irganox 1010 (manufactured by Ciba Geigy) 15
After adding 0 g, the pressure in the can was reduced to 500 mmHg to remove 25 kg of ethylene glycol. After that, 1.0% by weight of polyethylene glycol (molecular weight 1000) was added and polycondensation reaction was carried out. The obtained polymer was further held at 225 ° C. under vacuum for solid phase polymerization to obtain two types of polymers having [η] of 0.80 and 0.90. Next, each polymer was melt-spun under the conditions shown in Table 1 below. The apparent viscosities of these spinning properties are 8283 and 9100 [poise], respectively, and the shear rate is 906 sec.
It was ^-1 .

The undrawn yarn obtained from a polymer having an [η] of 0.8 was drawn under the drawing conditions shown in Table 2 to obtain 1000 denier.
A drawn yarn of 192 filaments was obtained. (Experiment No. 1 in Table 3) At this time, between the first hot roll and the second hot roll, the total length is 120 cm and the distance from the beginning to the end is 120 ° C / 1
A heating plate having a temperature gradient so as to be 35 ° C / 156 ° C / 176 ° C / 198 ° C / 230 ° C was provided.

Under the same drawing conditions, drawn yarn was obtained from a polymer having [η] of 0.9 (Experiment Nos. 2 and 3 in Table 3). Here, Experiment Nos. 2 and 3 were obtained by setting the draw ratio to 4.8 times and 4.0 times, respectively. Further, the same polymerization, spinning and drawing conditions as in Experiment No. 1 except that the copolymerization amounts of dimethyl (5-sodium sulfo) isophthalate were 1.1 and 1.9 (mol%), respectively. A drawn yarn of 5 was obtained.

Here, the apparent viscosity ηa at the time of spinning in Experiment Nos. 1 to 5 is
They were 8283, 9100, 9100, 6940, and 9510 [poise], respectively. The physical properties, dyeability, and temperature dependence coefficient (K _T ) of the dyed amount of each drawn yarn are also shown in Table 3. The amorphous orientation of the drawn yarn of Experiment No. 2 was 0.6, and the initial tensile modulus was 140.
g / d.

As is clear from Table 3, the fibers of Experiment Nos. 1 to 5 satisfying the requirements of the present invention all have good dyeability, and the temperature dependence coefficient (K _T ) of the dyeing amount is 2.0 or less, which is desirable. Fibers having a strength of When the fibers of Experiment Nos. 1 to 5 were evaluated as a seat belt, the mechanical properties and durability were excellent, and the quality was good with no stains.

Comparative Example 1 Dimethyl (5-sodium sulfo) in Example 1
The copolymerization amount of isophthalate (S component) was changed to the amount shown in Table 4.

In Experiment No. 11, the dyeability was low because the amount of S component copolymerized was small. On the other hand, in Experiment No. 12 in which the copolymerization amount of the S component was 2.2 mol%, the copolymerization amount of the S component was too large and the dyeability was good, but the apparent viscosity (ηa) was high and spinning was difficult. The obtained fiber also had low strength.

Also, except that the [η] of the chip is 0.65,
Experiment No. 13 of Comparative Example 1 obtained in the same manner as in Example 1
Fibers were low in strength.

In Experiment No. 14 in Table 5 in which the intrinsic viscosity of the yarn obtained from the same undrawn yarn as in Experiment No. 13 of Comparative Example 1 by changing the draw ratio was less than the lower limit of the present invention, K _T was within the range of the present invention. When used as a seat belt, the dyeing spots were large and satisfactory results could not be obtained. In Experiment No. 15, the same undrawn yarn as in Experiment No. 1 was used, but since the hot plate with the temperature gradient was not used, the degree of amorphous orientation of the drawn yarn was as low as 0.49, and K _T was within the range of the present invention. And the dyeing spots on the seat belt were large and a satisfactory yarn could not be obtained.

Example 2 Example 1 Modified polyester fiber (1000 denier 192 filaments) of Experiment No. 2 and ordinary polyester fiber (1
A seat belt was prepared by using 000 denier-192 filament Toray Co., Ltd. and changing the interweaving ratio to 80:20, 50:50 and 20:80. The resulting belt was immersed in a cationic dye bath and then heat set at 200 ° C., followed by being placed in a disperse dye bath and heat set at 200 ° C.

In the seat belt thus obtained, the modified polyester fiber was dyed with a cationic dye and the ordinary polyester fiber was dyed with a disperse dye, respectively, and dyed in two colors.
Thus, a seat belt having an unprecedented fashionability, good quality and excellent mechanical properties was obtained. However, the number 1 of the mixed weaving ratio (homopolyester fiber / high-strength modified polyester fiber of the present invention) 20/80 was slightly inferior in weatherability.

[Effects of the Invention] The high-strength modified polyester fiber according to the present invention has
Since it is a basic dye-dyeable fiber which has excellent mechanical properties such as modulus and durability and has good dyeability and color development, it can be developed as an industrial fiber such as a seat belt.

Claims (6)

(57) [Claims] 1. A modified polyester fiber obtained by copolymerizing an isophthalic acid component containing 1.1 to 1.9 mol% of a metal sulfonate group, having an intrinsic viscosity [η] of 0.65 or more and a drawn yarn strength of 6.0 g / d or more. A high-strength modified polyester fiber characterized by having a temperature dependence coefficient (K _T ) of the dyeing amount represented by the following formula: 2.0% / ° C or less. (M ₁₃₀ and M ₁₁₀ : Dyeing amount at 130 ° C and 110 ° C, respectively) 2. A high-strength modified polyester characterized in that the modified polyester according to claim (1) is obtained by copolymerizing a polyalkylene glycol represented by the following formula with a molecular weight of 400 to 6000 in an amount of 0.5 to 1.9% by weight. Polyester fiber. A (C _n H _2n O) _m H (A is C _l H _{2l + 1} O or OH, _l is 1 to 10, _n is 2 to 5, _m
Is 3 to 100) 3. A high-strength modified polyester fiber, characterized in that the strength of the drawn yarn according to claim (1) or (2) is 7.0 g / d or more. 4. A seat belt comprising the high-strength modified polyester fiber according to any one of claims (1), (2) and (3). 5. A seat belt obtained by interwoven with the high-strength modified polyester fiber according to claim 1, and polyester fiber different in dyeability from said fiber. 6. A high-strength modified polyester fiber according to claim 1, a polyester fiber not copolymerized with a third component, and a weaving ratio of 70/30 to 2/98. A seat belt made up of.