KR20200065646A - Polyester fiber for binder with improved processing property - Google Patents

Abstract

The present invention relates to a polyester fiber for a binder with improved processability. In the polyester fiber for a binder formed of a sheath portion and a core portion, the core portion is formed of a general polyester resin, and the sheath portion is formed of a low melting point polyester resin composed of an acid component composed of terephthalic acid or an ester-forming derivative thereof, and a diol component composed of 2-methyl-1,3-propanediol, 2-methyl-1,3-pentanediol, and ethylene glycol.

Description

Polyester fiber for binder with improved processing property

The present invention relates to a polyester fiber for a binder with improved processability, and an improved thermal processability while having improved spinning processability.

Polyester is an eco-friendly material, and has excellent mechanical properties, excellent heat resistance and chemical resistance, and can be used in various fields requiring light weight and high physical properties. Recently, the role of polyester fibers represented by polyethylene terephthalate (PET) is increasing in the field of fibers such as nonwoven fabrics. Specifically, there is an increasing demand for heat-adhesive fibers that can be used for clothing adhesive cores or automobile interior materials by using polyester resin as an adhesive component.

Accordingly, efforts to improve the physical properties of the polyester fiber and to expand the utilization thereof are underway from various angles, and as part of these efforts, the structure of the polyester resin is modified to control temperatures such as softening point or glass transition temperature. Are being studied. For example, a technique for adjusting the melting point or glass transition temperature of a polyester resin by copolymerizing dicarboxylic acids such as terephthalic acid, isophthalic acid, adipic acid and sebacic acid with diol compounds such as ethylene glycol and neopentyl glycol has been developed. have.

In particular, when manufacturing a web or sheet of non-woven fabric with polyester fiber, a heat-sealable binder polyester fiber used to bond filaments or short fibers has a heat-sealing processing temperature of 120 to 200°C, which is typical polyethylene tere It should have a lower melting point or softening point than phthalate fibers.

For this purpose, in synthesizing the polyester resin, it is a typical method to copolymerize with terephthalic acid using isophthalic acid as the copolymerization component. At this time, isophthalic acid is added in an amount of 20 to 45 mol% based on the mole of the ester, and the thus synthesized polyester resin is amorphous. Since it has a molecular structure in the form, it has a final melting point in the range of 145 to 180°C and can be used as a binder polyester fiber.

U.S. Patent No. 4,129,675 discloses a low-melting polyester binder composed mainly of terephthalic acid and isophthalic acid, but this is uneconomical because it requires a temperature of 200°C or higher during thermal bonding.

U.S. Patent No. 4,166,896 discloses a method for preparing an unsaturated polyester by copolymerizing unsaturated dicarboxylic acid and the like with a low molecular weight polymer depolymerized, but the fiber according to the patent is not only low in economic efficiency but also difficult to use as a binder. There are disadvantages that are too high melting point and high crystallinity.

U.S. Patent No. 4,065,439 discloses a low melting point polyester obtained using terephthalic acid/isophthalic acid/adipic acid (or sebacic acid) and ethylene glycol/neopentyl glycol, but the melting point of the binder is 45°C to 60°C. It is too low to be used as a wick for clothing, and also has poor shape stability under high temperature conditions.

On the other hand, Korean Patent Publication No. 2001-11548 condensates the dicarboxylic acid component of terephthalic acid and phthalic anhydride and the diol component of ethylene glycol and diethylene glycol, and has excellent adhesion to polyester, and does not cause yellowing after adhesion. Although a binder for an ester-based fiber is provided, the binder has a disadvantage in that the reaction mechanism is complicated by directly using phthalic anhydride, and thus the condensation polymerization temperature must be lowered to prevent the problem of poor color of the copolymerized polyester. In addition, such a low-temperature condensation polymerization reaction has a problem of deteriorating operating productivity.

In addition, in the case of manufacturing a low-melting point heat-adhesive fiber in the form of a sheath-core, in the case of a low-melting material used in the sheathing part, an extruder (Extruder) during the spinning process compared to a general polyester resin in the core part due to low melting point (or softening point) It is common to set the temperature of low to proceed with spinning.

In this case, the temperature of each extruder of the sheath part and the core part has a temperature difference of about 30-50°C, but the flowability control of the general polyester resin having a high melting point in the nozzle part for the two polymers to pass through the extruder and for spinning and In order to prevent solidification, it is set to a high temperature of 280°C or higher.

As described above, the polyester resin of the sheath portion melted at a high temperature at the nozzle portion is a low-melting point material, and the melt viscosity is extremely reduced, causing excessively high flowability, resulting in non-uniformity in fibers (eccentricity, etc.), and processability such as warping and trimming when spinning. There was a problem of lowering, and lowering the uniformity of the physical properties of the polyester fiber produced.

The present invention was invented to solve the problems of the prior art as described above, and the polyester resin forming the sheath portion at the time of manufacturing the sheath-core type polyester fiber for a binder does not significantly decrease the melt viscosity even at high temperatures. An object of the present invention is to provide a polyester fiber for a binder having improved processability.

In addition, an object of the present invention is to provide a polyester fiber for a binder having improved processability, improved physical properties, and improved processability.

The present invention is a polyester fiber for a binder formed of a sheath part and a core part, wherein the core part is formed of a general polyester resin, and the sheath part is an acid component composed of terephthalic acid or an ester-forming derivative thereof, and 2-methyl-1. It provides a polyester fiber for improved processability characterized in that it is formed of a low-melting polyester resin formed of a diol component consisting of, 3-propanediol, 2-methyl-1,3-pentanediol, and ethylene glycol. .

In addition, 2-methyl-1,3-pentanediol of the low melting point polyester resin provides a polyester fiber for improved processability, characterized in that it contains 0.01 to 5 mol% of the diol component.

In addition, 2-methyl-1,3-pentanediol of the low melting point polyester resin provides a polyester fiber for improved processability characterized in that it contains 0.05 to 2 mol% of the diol component.

In addition, the low-melting polyester resin provides a polyester fiber for improved processability, characterized in that the difference between the melting viscosity of 220°C and the melting viscosity of 260°C is 600 poises or less.

In addition, the general polyester resin of the core portion is characterized in that the melt viscosity of 280 °C is 2,000 to 4,000 poise, and the polyester resin of the sheath portion is 600 to 1,500 poise of 260 °C. Provided is a polyester fiber for a binder with improved processability.

In addition, it provides a nonwoven fabric comprising the polyester fiber for the binder.

As described above, the polyester fiber for a binder having improved processability according to the present invention has a non-uniform cross-section in the spinning process because the low-melting-point polyester resin forming the sheath portion at the time of manufacturing the sheath-core polyester fiber does not significantly decrease the melt viscosity even at high temperatures. , By suppressing phenomena such as warp, trimming, etc., there is an effect that the spinning processability is greatly improved.

In addition, the polyester fiber for a binder having improved processability of the present invention has an effect of improving processability and improving physical properties and adhesion.

Hereinafter, a preferred embodiment of the present invention will be described in detail. First, in describing the present invention, detailed descriptions of related known functions or configurations will be omitted so as not to obscure the subject matter of the present invention.

As used herein, the terms'about','substantially', etc. are used in the sense of or close to the numerical values when manufacturing and material tolerances unique to the stated meaning are presented, and to understand the present invention. To aid, accurate or absolute figures are used to prevent unscrupulous use of the disclosed disclosure by unscrupulous infringers.

The present invention relates to a polyester fiber for a binder formed of a sheath portion and a core portion, and the core portion is formed of a general polyester resin and the sheath portion is a polyester fiber formed of a low melting polyester resin.

Any of the general polyester resins forming the core part can be used, but it will be preferable to use polyethylene terephthalate (PET) resin made of terephthalic acid and ethylene glycol.

The low-melting polyester resin forming the sheath portion is an acid component composed of terephthalic acid or an ester-forming derivative thereof, and 2-methyl-1,3-propanediol (2-Methyl 1,3 Prorpanediol), 2-methyl-1, It is a polyester resin formed of a diol component composed of 3-pentanediol (2-Methyl 1,3 Pentanediol) and ethylene glycol (EG).

The 2-methyl-1,3-propanediol used in the present invention is a methyl group bonded to the second carbon to facilitate the rotation of the polymer main chain and acts as if it is the end of the polymer, widening the free space between the main chains, and the entire molecular chain. Increase the flowability of This makes the polymer amorphous and has the same thermal properties as isophthalic acid. Due to the flexible molecular chain present in the polymer main chain, it improves elasticity and plays a role in improving the tearing property when binding the nonwoven fabric.

That is, 2-methyl-1,3-propanediol contains a methyl group (-CH ₃ ) in the ethylene chain bound to terephthalate as a side chain to secure a space so that the main chain of the polymerized resin can rotate, thereby freeing the main chain. The softening point (Ts) and/or the glass transition temperature (Tg) can be controlled by inducing an increase and a decrease in the crystallinity of the resin. This may exhibit the same effect as when using isophthalic acid (IPA) containing an asymmetric aromatic ring to lower the crystallinity of a conventional crystalline polyester resin.

The 2-methyl-1,3-pentanediol, like the 2-methyl-1,3-propanediol, has a methyl group attached to the second carbon to facilitate rotation of the polymer main chain and impart low melting point properties to the polyester resin. It has the characteristics of, and increases the melt viscosity of the polyester resin with a molecular chain longer than 2-methyl-1,3-propanediol, thereby preventing the melt viscosity from rapidly decreasing at high temperatures.

The low-melting polyester resin of the present invention formed of the above-mentioned diol component has 20 to 50 moles of 2-methyl-1,3-propanediol of the low-melting polyester resin in order to improve the low melting point properties and adhesion. % Will be preferred.

If the 2-methyl-1,3-pentanediol is contained in less than 0.01 mol% of the diol component, the effect of improving the melt viscosity is negligible, and when it exceeds 5 mol%, the melt viscosity increases rapidly and the spinning processability may be reduced. 2-methyl-1,3-pentanediol will preferably contain 0.01 to 5 mol% of the diol component.

The 2-methyl-1,3-pentanediol will most preferably contain 0.05 to 2 mol%.

As described above, the low-melting polyester resin of the sheath portion containing 2-methyl-1,3-pentanediol has a difference in melting viscosity of 220°C and melting point of 260°C at a high temperature of 600 poises or less, and the melt viscosity at high temperatures. It has a characteristic that does not drop rapidly.

The lower the difference between the melting viscosity of 220°C and the melting viscosity of 260°C of the low-melting polyester resin is, the lower is preferable, and more preferably 500 poise or less.

The polyester fiber for the binder of the present invention is a sheath-core type composite fiber, and for the spinning property of the composite fiber in the spinning process, the general polyester resin of the core portion has a melt viscosity of 280°C of 2,000 to 2,500 poise, and the sheath The negative polyester resin will preferably have a melt viscosity of 260°C of 500-1,400 poise.

If the melt viscosity of the general polyester resin of the core portion is too high, the spinning processability may be lowered to cause a trimming phenomenon, and if the melt viscosity of the core portion is lower than that of the polyester resin of the sheath portion, the shape stability of the composite fiber may be reduced. That is, the sheath-core type fiber cross-section may not be formed, and the general polyester resin of the core portion may preferably have a melt viscosity of 280°C to 2,000-4,000 poise.

The polyester resin of the sheath portion is too high and the shape stability of the composite fiber may be deteriorated. If the melt viscosity of the sheath portion is too low, non-uniformity of cross-section, warpage, trimming, etc. may occur. The resin preferably has a melt viscosity of 260°C of 600-1,500 poise, and more preferably a melt viscosity of 260°C of 700 poise or more.

The melting point of the general polyester resin forming the core portion and the melting viscosity of the polyester resin forming the sheath portion are advantageous in improving the shape stability and spinning processability of the composite fiber in a certain range. It is preferable that the difference between the melt viscosity of 280°C of the resin and the melt viscosity of 260°C of the polyester resin forming the sheath portion is 700 to 2,500 poise, more preferably 1,000 to 2,000 poise difference.

The low-melting polyester resin of the present invention containing 2-methyl-1,3-propanediol and 2-methyl-1,3-pentanediol as described above has a softening temperature of 100°C to 150°C, and a glass transition temperature. It has excellent physical properties of 50°C to 90°C and an intrinsic viscosity of 0.50 Pa/g or more.

The polyester fiber for a binder having improved processability of the present invention as described above can not only be heat-sealed at a low temperature in a range similar to the temperature applied to the existing binder fiber, but also improves the processability so that the properties of the fiber are uniform and the adhesion is improved. As the glass transition temperature is 60℃ or higher, the strength is maintained even when durability and shape stability are required in a high temperature atmosphere, such as a product for automobile interior, and it has the advantage of preventing sagging in a high temperature atmosphere even in a non-woven fabric for molding. It can be used for non-woven fabrics for various purposes.

Hereinafter, an example of a method for producing a polyester fiber for improved processability according to the present invention is shown, but the present invention is not limited to the examples.

Example 1 to 6

Polyethylene terephthalate having a melt viscosity of about 2,300 poise at 280°C was used as the core portion, and the sheath portion was made of low-melting polyester resin, and the weight ratio of the sheath portion and the core portion was 50:50. A polyester fiber for a binder having improved processability was prepared.

The low melting point polyester resin is added to terephthalic acid (TPA) and ethylene glycol (EG) in an ester reaction tank, and a typical polymerization reaction is performed at 258°C to prepare a polyethylene terephthalate polymer (PET oligomer) having a reaction rate of about 96%. Did. 2-Methyl-1,3-propanediol contained about 42 mol% of the diol component in the prepared polyethylene terephthalate (PET), and the content ratio of 2-methyl-1,3-pentanediol shown in Table 1 below The mixture was mixed with and transesterification reaction was performed at 250±2° C. by adding a transesterification catalyst. Then, a condensation polymerization reaction catalyst was added to the obtained reaction mixture, and the final temperature and pressure in the reaction tank were adjusted to be 280±2° C. and 0.1 mmHg, respectively, to prepare a condensation polymerization reaction.

Comparative Example 1

In the same manner as in Example 1, polyethylene terephthalate was used as the core part, and the low melting point polyester resin of the cis part used terephthalic acid (66.5 mol%) and isophthalic acid (33.5 mol%) as the acid component, and diethylene as the diol component. It was prepared using glycol (10.5 mol%) and ethylene glycol (89.5 mol%).

Comparative Example 2

Polyethylene terephthalate was used as the core part in the same manner as in Example 1, and terephthalic acid was used as the acid component for the low-melting polyester resin of the cis part, and 2-methyl-1,3-propanediol (42.5 mol%) as the diol component. , It was prepared using ethylene glycol (57.5 mol%).

division Softening point
(℃) Tg
(℃) IV
(dl/g) 2-methyl-1,3-pentanediol (mol%) Melt viscosity 220℃ 240℃ 260℃ Example 1 122 60.9 0.561 0.1 1254 1019 783 Example 2 119 61.8 0.562 0.5 1314 1078 864 Example 3 120 61.9 0.562 1.0 1528 1387 1196 Example 4 123 63.5 0.562 2.0 2271 1739 1444 Example 5 123 64.8 0.563 3.5 2833 2571 2213 Example 6 126 67.3 0.561 5.0 3341 3041 2733 Comparative Example 1 113 56.8 0.563 0 1011 739 467 Comparative Example 2 121 61.5 0.561 0 1197 992 664

As shown in Table 1, it can be seen that as the content of 2-methyl-1,3-pentanediol increases, the melt viscosity increases, and in Examples 1 to 6, the melt viscosities of 260°C are all higher than 700 poise at high temperatures. It can be seen that the melt viscosity is maintained.

In addition, in Examples 2 to 4, in which 2-methyl-1,3-pentanediol was contained in 0.5 to 2 mol% of the diol component, the difference between the melting viscosity of 220°C and the melting viscosity of 260°C was 300 to 500 poise. It can be seen that the difference is lower than Comparative Examples 1 and 2, which are 684 and 674 poises.

In addition, as in Examples 5 and 6, when 2-methyl-1,3-pentanediol is contained in 3 mol% or more of the diol component, it can be seen that the melting viscosity of 260°C is rapidly increased to 2,000 poise or more. .

◈ Measurement of physical properties of Examples and Comparative Examples

By measuring the following physical properties of the polyester fiber for a low-melting polyester resin and a binder prepared in Examples and Comparative Examples, the results are shown in Tables 1 and 2.

(1) Softening point (or melting point) and glass transition temperature (Tg) measurement

The glass transition temperature (Tg) of the copolymerized polyester resin was measured using a differential scanning calorimeter (Perkin Elmer, DSC-7), and the softening behavior in the TMA mode was measured using a dynamic mechanical analyzer (DMA-7, Perkin Elmer). Did.

(2) Intrinsic viscosity (IV) measurement

After the polyester resin was dissolved at a concentration of 0.5% by weight in a solution in which phenol and tetrachloroethane were mixed at a 1:1 weight ratio, intrinsic viscosity (I.V) was measured at 35°C using a Uberod viscometer.

(3) Melt viscosity measurement

After the polyester resin was melted at the measured temperature, the melt viscosity was measured using RDA-III from Rheometric Scientific. Specifically, when measured by setting from the initial frequency = 1.0 rad/s to the final frequency = 500.0 rad/s under the frequency sweep condition at the set temperature, the value at 100 rad/s was calculated as the melt viscosity.

(4) Measurement of compressive hardness

After opening 5 g of polyester fibers and stacking them at a height of 5 cm in a circular mold having a diameter of 10 cm, heat-sealing at a set temperature for 90 seconds to produce a cylindrical shaped article. The manufactured molded product was compressed by 75% through Instron to measure the load applied to compression, and the compressive hardness was measured. In this experiment, compressive hardness was measured by heat bonding at 140℃, 150℃, and 160℃ respectively.

(5) Measurement of emissivity (%, 24hr)

The spinning yield was calculated by measuring the amount of polyester resin used for 24 hours and the amount of spun fiber.

Spinning yield (%) = (Amount of spun fiber (kg) / amount of PET resin used (kg)) * 100

division Compressive hardness (kgf) Emission yield
(%, 24hr) 140℃ 150℃ 160℃ Example 1 0.55 0.72 0.98 98.5 Example 2 0.57 0.79 1.07 99.2 Example 3 0.62 0.88 1.21 99.3 Example 4 0.61 1.24 1.36 99.5 Example 5 0.73 1.39 1.55 95.6 Example 6 0.76 1.54 1.86 91.3 Comparative Example 1 0.41 0.57 0.74 97.8 Comparative Example 2 0.52 0.73 0.91 98.1

The higher the compression hardness, the better the thermal adhesion between the fibers of the molded article. As shown in Table 2, Examples 1 to 6, which are polyester fibers for the binder of the present invention, have higher compression hardness than Comparative Examples 1 and 2. It can be seen that the heat sealability is excellent,

In addition, the difference between the melting viscosity of 220°C and the melting viscosity of 260°C is low. Examples 2 to 4 show that the spinning yield has a higher value, and the binder polyester fiber of the present invention has excellent processability and high processability. It can be seen that the heat sealability is improved.

In addition, as in Examples 5 and 6, when 2-methyl-1,3-pentanediol is contained in 3 mol% or more of the diol component, it can be seen that the spinning yield is lowered due to a high melt viscosity.

Particularly, Examples 2 to 4 in which 2-methyl-1,3-pentanediol is contained in 0.5 to 2.0 mol% of the diol component is very excellent in compressive hardness and emissivity, and the 2-methyl-1,3-pentanediol is a diol. It will be preferable to contain 0.5 mol to 2.0 mol% of the components.

Claims (6)

In the polyester fiber for a binder formed of a sheath portion and a core portion,
The core portion is formed of a general polyester resin,
The cis part is a low melting point formed of an acid component composed of terephthalic acid or an ester-forming derivative thereof, and a diol component composed of 2-methyl-1,3-propanediol, 2-methyl-1,3-pentanediol, and ethylene glycol. A polyester fiber for a binder having improved processability, which is formed of a polyester resin. According to claim 1,
2-methyl-1,3-pentanediol of the low-melting polyester resin is a polyester fiber for improved processability characterized in that it contains 0.01 to 5 mol% of the diol component. According to claim 1,
2-methyl-1,3-pentanediol of the low-melting polyester resin is a polyester fiber for improved processability, characterized in that it contains 0.05 to 2 mol% of the diol component. According to claim 1,
The low-melting polyester resin is a polyester fiber for improved processability, characterized in that the difference between the melting viscosity of 220 ℃ and the melting viscosity of 260 ℃ is less than 600 poise (poise). According to claim 1,
The general polyester resin of the core portion has a melt viscosity of 280°C to 2,000 to 2,500 poise, and the polyester resin of the sheath portion has a melt viscosity of 260°C to 600 to 1,500 poise. Improved polyester fiber for binders. Non-woven fabric comprising the polyester fiber for a binder according to any one of claims 1 to 5.