KR101831879B1 - Polyester fiber using binder Having Advanced Adhesive Strength - Google Patents

Abstract

The present invention relates to a polyester fiber for binders having improved adhesive strength. The polyester fiber for binders comprises a sheath unit and a core unit. The core unit is formed of a general polyester resin, and the sheath unit is formed of a low melting point copolymerization polyester resin comprising: acidic components comprising terephthalic acid (TPA), isophthalic acid (IPA) or an ester-forming derivative thereof; and diol components comprising 2-methyl-1,3-propanediol (MPD), diethylene glycol (DEG), and ethylene glycol (EG). When a mole% of the isophthalic acid or the ester-forming derivative thereof among the acidic components refers to A, a mole% of 2-methyl-1,3-propanediol among the diol components refers to B, and a mole% of the diethylene glycol refers to C, the present invention satisfies all of formula (1), 40 <= A+B+C <= 60, formula (2), 0.5 <= A/B <= 2.0, and formula (3), 1.0 <= B/C, and has 50 kgf or more of an adhesive strength at room temperature and 4 kgf or more of an adhesive strength at high temperature.

Description

TECHNICAL FIELD [0001] The present invention relates to a polyester fiber for binder having improved adhesion strength. [0002] Having Advanced Adhesive Strength

The present invention relates to a polyester fiber for a binder having an improved adhesive strength, and relates to a polyester fiber for a binder having an improved bonding strength that maintains high adhesive strength even at room temperature and high temperature.

The thermally fusible binder fibers used to bond the filaments or staple fibers constituting the web or sheet of the nonwoven fabric should have a glass transition temperature close to that of a regular polyethylene terephthalate fiber with a heat bonding temperature of 140 to 150 ° C To do this, it is necessary to eliminate the crystal structure in the polymer and make the polymer structure into an amorphous form.

For this purpose, it is typical to copolymerize terephthalic acid with isophthalic acid as a copolymerization component in the synthesis of polyester resin, wherein isophthalic acid is added in an amount of 20 to 45 mol% based on the ester molar amount, and the polyester resin thus synthesized is amorphous And has a final melting point ranging from 145 to 180 ° C and can be used as a polyester fiber for a binder.

U.S. Patent No. 4,129,675 discloses a low melting point polyester binder based on terephthalic acid and isophthalic acid, but it is uneconomical because it requires a temperature of 200 ° C or more in heat bonding.

U.S. Patent No. 4,166,896 discloses a method for producing an unsaturated polyester by copolymerizing unsaturated dicarboxylic acid or the like with a low-molecular-weight water having depolymerized polyester, but the fiber according to the patent also has low economic efficiency, There is a disadvantage that it is excessively 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 not only difficult to use as a garment wick but also has low dimensional stability under high temperature conditions.

On the other hand, Korean Patent Laid-Open Publication No. 2001-11548 discloses a polyester resin composition comprising a dicarboxylic acid component of terephthalic acid and a phthalic anhydride, and a diol component of ethylene glycol and diethylene glycol, which are excellent in adhesion to polyester, Although the binder for ester-based fibers is provided, the binder is complicated in the reaction mechanism by directly using anhydrous phthalic acid, and thus has a disadvantage in that the condensation polymerization temperature must be lowered in order to prevent the problem of poor color of the copolymer polyester. In addition, such a low temperature polycondensation reaction has a problem in that the productivity is lowered.

In addition, the conventional polyester-based binder fibers have the problem that the adhesiveness is maintained at room temperature but the adhesiveness is rapidly deteriorated at a high temperature, which can not be used in various industrial fields.

It is an object of the present invention to provide a polyester fiber for a binder having improved adhesion strength that maintains an adhesive strength even at room temperature and high temperature.

Further, it is possible to improve the adhesion strength between the adjacent fibers due to the low glass transition temperature of the polyester fiber for binder during the drawing process through the low melting point copolymerized polyester resin having a glass transition temperature of 60 ° C or higher. It is an object of the present invention to provide a polyester fiber.

The present invention relates to a polyester fiber for a binder formed of a sheath portion and a core portion, wherein the core portion is formed of a general polyester resin, and the sheath portion is formed of an acidic (terephthalic) acid and an isophthalic acid (IPA) And a low melting point copolymer polyester resin formed of a diol component composed of 2-methyl-1,3-propanediol (MPD), diethylene glycol (DEG), and ethylene glycol (EG) (1) to (3), wherein A represents a molar percentage of isophthalic acid or its ester-forming derivative thereof, B represents molar% of 2-methyl-1,3-propanediol in the diol component, (3), a room temperature bonding strength of 50 kgf or more, and a high temperature bonding strength of 4 kgf or more.

(1) 40? A + B + C? 60

(2) 0.5? A / B? 2.0

(3) 1.0? B / C

The isophthalic acid or its ester-forming derivative of the low melting point copolymerized polyester resin may be used in an amount of 10 to 20 mol% in the acid component, 2-methyl-1,3-propanediol in the diol component in an amount of 10 to 40 mol% Wherein the glycol contains 10 to 20 mol% of the diol component.

In addition, the low melting point copolymerized polyester resin has a softening temperature of 110 ° C to 130 ° C. The polyester fiber for a binder having improved adhesion strength is provided.

Also, the low melting point copolymerized polyester resin has a glass transition temperature of 60 ° C to 70 ° C. The polyester fiber for a binder having improved adhesion strength is provided.

The present invention also provides a nonwoven fabric comprising the polyester fiber for a binder as described above.

As described above, the polyester fiber for a binder having an improved bonding strength according to the present invention has a high adhesive strength at room temperature, and has an effect of maintaining an adhesive strength of a certain level or higher even at a high temperature.

When the glass transition temperature (Tg) of the low-melting-point copolymerized polyester resin forming the sheath portion of the polyester fiber for a binder is 60 ° C or higher, the stability of the spinning process is improved, The adhesion phenomenon can be prevented.

Hereinafter, a preferred embodiment of the present invention will be described in detail. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as to avoid obscuring the subject matter of the present invention.

As used herein, the terms &quot; about, &quot; &quot; substantially, &quot; &quot; etc. &quot;, when used to refer to a manufacturing or material tolerance inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

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

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

The low melting point copolymer polyester resin forming the sheath portion may be an acid component composed of terephthalic acid (TPA) and isophthalic acid (IPA) or an ester-forming derivative thereof, and an acid component comprising 2-methyl-1,3-propanediol (MPD) Ethylene glycol (DEG), and ethylene glycol (EG).

The isophthalic acid (IPA) or an ester-forming derivative thereof contained in the acid component is a compound that lowers the melting point of the polyester resin without lowering the glass transition temperature (Tg) of the polyester resin. It is a widely used compound.

2-methyl-1,3-propanediol (MPD) used in the present invention is a polymer having a methyl group bonded to a second carbon to facilitate rotation of the polymer main chain and to act as a polymer end portion, Thereby increasing the possibility of flow of the entire molecular chain. This makes the polymer irregular and has the same thermal properties as isophthalic acid. It improves elasticity due to the flexible molecular chains present in the polymer backbone and improves tear properties during nonwoven binding.

That is, 2-methyl-1,3-propanediol has a methyl group (-CH ₃ ) as a side chain in an ethylene chain bonded to terephthalate and secures a space for the main chain of the polymerized resin to rotate, And the softening point (Ts) and / or the glass transition temperature (Tg) can be controlled by inducing a decrease in crystallinity of the resin. This may have the same effect as in the case of using isophthalic acid (IPA) containing an asymmetric aromatic ring in order to lower the crystallinity of the conventional crystalline polyester resin.

The diethylene glycol (DEG), like the 2-methyl-1,3-propanediol, improves the thermal properties by widening the free space between the main chains.

In the present invention, the content of isophthalic acid (IPA) or an ester-forming derivative thereof contained in the acid component and the content of 2-methyl-1,3-propanediol (MPD) and diethylene glycol The softening temperature and the glass transition temperature (Tg) of the low melting point copolymer polyester resin are controlled.

In order to improve the adhesion of the low melting point copolymerized polyester resin used in the present invention, the isophthalic acid or the ester forming derivative of the low melting point copolymerized polyester resin is used in an amount of 10 to 20 mol% Propanediol is preferably contained in an amount of 10 to 40 mol% of the diol component and 10 to 20 mol% of diethylene glycol in the diol component. More specifically, it is preferred that the isophthalic acid or the ester- It is preferable that the mol% is A, the molar% of the 2-methyl-1,3-propanediol in the diol component is B, and the molar% of diethylene glycol is C to satisfy all the following formulas (1) to (3) will be.

(1) 40? A + B + C? 60

(2) 0.5? A / B? 2.0

(3) 1.0? B / C

When the content (A + B + C) of isophthalic acid or its ester-forming derivative, 2-methyl-1,3-propanediol and diethylene glycol is less than 40 mol% as in the above formula (1) If it exceeds 60 mol%, the physical properties of the low melting point copolymerized polyester resin may be deteriorated.

When A / B is less than 0.5, that is, when the content of 2-methyl-1,3-propanediol is two times or more higher than that of isophthalic acid or an ester-forming derivative thereof as in the formula (2) When the content of isophthalic acid or an ester-forming derivative thereof is two times or more than the content of 2-methyl-1,3-propanediol, the hardness is lowered and the polymerization The production of the cyclic compound as a side reaction product in the process can be enhanced. The most preferable numerical value of the A / B value of the formula (2) is 1.0? A / B? 2.0.

When B / C is less than 1.0, that is, when the content of diethylene glycol is more than 2-methyl-1,3-propanediol as shown in the formula (3), the glass transition temperature (Tg) And the shape stability of the nonwoven fabric may be deteriorated at the time of production.

When the content of 2-methyl-1,3-propanediol is contained in the diol component in an amount of 20 mol% or more, the production of a cyclic compound as a side reaction product in the polyester polymerization process is also inhibited.

As described above, the softening temperature of the low melting point copolymer polyester resin of the present invention, in which the content of 2-methyl-1,3-propanediol and diethylene glycol is controlled, is controlled at 110 ° C to 130 ° C and the glass transition temperature is 60 ° C To 70 ° C, and an intrinsic viscosity of 0.55 dl / g or more.

As described above, the polyester fiber for a binder having improved adhesion strength of the present invention having a low melting point copolymerized polyester resin as described above has an excellent adhesive force at room temperature adhesive strength of 50 kgf or more and has a high adhesive force of 4 kgf or more maintain.

The polyester fiber for a binder having the improved adhesive strength of the present invention as described above can be thermally adhered at a low temperature in a range similar to the temperature applied to conventional binder fibers and also has a glass transition temperature of 60 ° C or higher, The strength is maintained even when durability and shape stability are required in a high temperature atmosphere, and the molding nonwoven fabric has an advantage of preventing sagging under a high temperature atmosphere and can be used for nonwoven fabrics for various purposes.

Hereinafter, examples of the method for producing a polyester fiber for a binder having an improved adhesive strength according to the present invention are shown, but the present invention is not limited to the examples.

Example  1 to 3

Polyethylene terephthalate was used as a core part and a low melting point copolymer polyester resin was used as a sheath part to produce a polyester fiber for a binder having an improved bonding strength of the present invention through a general composite spinning process.

(TPA) and ethylene glycol (EG) are fed into an ester reaction tank, and a typical polymerization reaction is carried out at 258 ° C to obtain a polyethylene terephthalate polymer (PET oligomer) having a reaction rate of about 96% . 2-methyl-1,3-propanediol (MPD), diethylene glycol (DEG) and isophthalic acid (IPA) were mixed in the polyethylene terephthalate (PET) The ester exchange reaction was carried out at 250 ± 2 ° C by adding an ester exchange catalyst. Thereafter, a condensation polymerization catalyst was added to the obtained reaction mixture, and the final temperature and pressure in the reaction vessel were adjusted to 280 ± 2 ° C and 0.1 mmHg, respectively, to perform condensation polymerization.

Comparative Example  One

Polyethylene terephthalate was used as the core part in the same manner as in Example 1, and a low melting point copolymer polyester resin was used as the sheath part, but the low melting point copolymer polyester resin of the sheath part was composed of terephthalic acid (TPA), isophthalic acid , IPA) was used as a diol component and diethylene glycol (DEG) and ethylene glycol (EG) were used as diol components.

Comparative Example  2

Polyethylene terephthalate was used as the core part in the same manner as in Example 1, and the low melting point copolymer polyester resin of the sheath portion was used as the sheath portion, but terephthalic acid (TPA) as the acid component and diethylene Glycol (DEG), and ethylene glycol (EG).

division Acid content (mol%) Diol component (mol%) IPA TPA MPD DEG EG Example 1 10 90 20 10 70 Example 2 10 90 20 15 65 Example 3 20 80 10 15 75 Comparative Example 1 30 70 0 15 85 Comparative Example 2 0 100 0 30 70

◈ Measurement of physical properties of examples and comparative examples

The following properties of the low melting point copolymerized polyester resin and the polyester fiber for binder produced in the above Examples and Comparative Examples were measured, and the results are shown in Table 3 below.

(1) Measurement of softening point (Ts) and glass transition temperature (Tg)

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 was measured in a TMA mode using a dynamic mechanical analyzer (DMA-7, Perkin Elmer) Respectively.

(2) Intrinsic viscosity (IV) measurement

The polyester resin obtained in Examples and Comparative Examples was dissolved in a solution of phenol and tetrachloroethane in a weight ratio of 1: 1 at a concentration of 0.5 wt%, respectively, and the intrinsic viscosity (IV ) Were measured.

(3) Adhesion measurement at normal temperature and high temperature

The nonwoven fabrics having the density fixed to 2 g / 100 cm 2 were prepared by thermally fusing the polyester fibers of the examples and the comparative examples. The prepared nonwoven fabric was subjected to heat treatment at 25 ± 0.5 ° C. (room temperature) and 100 ± 0.5 ° C. (high temperature) according to ASTM D1424 The adhesive strength was measured.

(4) High temperature shrinkage

The polyester fiber for a binder is made into a short fiber and then carded into a cylindrical shape. After heating at 170 ° C for 3 minutes, the reduced volume is measured. As the volume is reduced to 330 cm 3, it can be evaluated that the shape stability is not good as the volume is reduced. Generally, when it is 250 cm 3 or less, the form stability is inferior, and when it is 280 cm 3 or more, it can be evaluated as excellent.

division Thermal properties
IV
(dl / g) Adhesion
Morphological stability Softening temperature
[° C] Tm
[° C] Tg
[° C] Adhesion at room temperature
[kgf] High temperature adhesion
[kgf] High temperature shrinkage
[Cm 3] Example 1 120 - 62.0 0.579 61 4.2 271 Example 2 115 - 60.7 0.582 54 4.2 263 Example 3 125 - 60.5 0.579 64 4.0 267 Comparative Example 1 112 - 61.0 0.579 55 3.2 263 Comparative Example 2 - 199.7 57.7 0.581 56 1.8 259

As shown in Table 2, in Examples 1 to 3, the low melting point copolymer polyester resin of the present invention has a softening point of 110 to 130 캜, which indicates excellent low melting point characteristics. The glass transition temperature (Tg) Lt; 0 &gt; C or more, which is superior to the comparative example.

In Examples 1 to 3 and Comparative Examples, the adhesive strength at room temperature was found to be excellent at not less than 55 kfg. However, in Examples 1 to 3, the adhesive strength at room temperature was not less than 4.0 kfg, kfg. &lt; / RTI &gt;

In addition, in Examples 1 to 3 and Comparative Examples at the time of producing the nonwoven fabric, the high temperature shrinkability was found to be at a satisfactory level of 260 cm 3 or more.

Claims (5)

A 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 cis portion is composed of an acid component composed of terephthalic acid (TPA) and isophthalic acid (IPA) or an ester-forming derivative thereof, and an acid component comprising 2-methyl-1,3-propanediol (MPD) A low melting point copolymerized polyester resin formed of a diol component composed of ethylene glycol (DEG), and ethylene glycol (EG)
Wherein A represents the molar percentage of the isophthalic acid or its ester-forming derivative in the acid component, B represents the molar percentage of 2-methyl-1,3-propanediol in the diol component, and C represents the molar percentage of diethylene glycol 1) to (3), a room temperature bonding strength of 50 kgf or more, and a high temperature bonding strength of 4 kgf or more.
(1) 40? A + B + C? 60
(2) 0.5? A / B? 2.0
(3) 2.0? B / C The method according to claim 1,
The isophthalic acid or its ester-forming derivative of the low-melting-point copolymer polyester resin is used in an amount of 10 to 20 mol% in the acid component, 2-methyl-1,3-propanediol in the diol component in an amount of 10 to 40 mol% Wherein the polyester fiber comprises 10 to 20 mol% of the diol component. The method according to claim 1,
Wherein the low melting point copolymerized polyester resin has a softening temperature of 110 ° C to 130 ° C. The method according to claim 1,
Wherein the low melting point copolymerized polyester resin has a glass transition temperature of 60 ° C to 70 ° C. A nonwoven fabric comprising a polyester fiber for a binder according to any one of claims 1 to 4.