KR100407035B1 - Polyester binder fiber - Google Patents

Abstract

The invention of high-melting point polyethylene terephthalate, and as a low melting point copolyester has a composite spinning poly relates to ester-based binder fiber of the copolymer having a low melting point polyethylene terephthalate adipate having a molecular weight of 600-2000 as the first acid copolymer component 1,4-butanediol polyol and 1,4-butanediol is a polyester copolymerized as the second copolymer component, and the polyester binder fiber having such a copolyester as a low melting point component is the toughness of the final product. It provides an excellent tensile behavior when manufacturing nonwoven fabric by preventing the increase and the decrease of cutting strength as much as possible, and there is an advantage such that the nonwoven fabric strength is hardly reduced even at high temperature.

Description

Polyester binder fiber {Polyester binder fiber}

The present invention relates to a polyester-based binder fiber, and more particularly to a polyester-based binder fiber composite spun with conventional polyethylene terephthalate as a high melting point component and crystalline copolyester as a low melting point component.

In general, a padding product for clothing is a method of carding short fibers, laminating several layers of carding web products in a machine direction and a semi-machine direction, and then having inter-fiber adhesion as an adhesive material (binder). have.

Such nonwoven fabrics can be classified into two types. One method is to apply a single fiber to give adhesiveness, and then dissolve a resin such as polyvinyl alcohol or acrylic in a solvent and apply it to the surface of the nonwoven fabric. Another method is to bond the constituent fibers by heat treatment after mixing the binder fibers prepared by in-situ or sheath-core composite spinning in a matrix fiber with a certain ratio of melting point to the matrix fibers as in the present invention Way.

However, the method of dissolving and spraying polyvinyl alcohol or acrylic resin, which is the former method, is not only able to penetrate deeply to the inside of the web, but also due to environmental pollution by solvent and low compatibility with polyester which becomes a matrix. Due to the limited use of only the wick for clothing to simply adhere the surface of the non-woven fabric, there is a disadvantage that can not be applied to products requiring high strength due to low adhesiveness and rough touch. In addition, the organic solvents used are mostly volatile and harmful to the human body, and when used as a nonwoven fabric for molding, it is pointed out that the solvent and resin are buried in the mold.

The latter method is a method that does not use a solvent, and has a great advantage of instantaneous adhesion by heating, and in the field of fiber bonding, it contributes to the rationalization, personnel reduction, and speedup of the bonding process. Products are being developed and commercialized. However, the method of mixing and splicing the same matrix type or heterogeneous polymer with low melting point with cis-core type and side-by-side type and melt bonding during heat treatment has good compatibility between fibers. Because of the melting point, different components should be copolymerized to the polyester to lower the melting point.

One example of a technique using copolyester binder fibers to make nonwoven webs and sheets robust is described in US Pat. No. 3,989,788. Here, the copolyester binder is a method of obtaining the characteristics as a binder by changing some terephthalate repeating units in the polyethylene terephthalate into isophthalate units.

As another example, a method of using dicarboxylic acid, aromatic dicarboxylic acid such as isophthalic acid and phthalic acid or aliphatic dicarboxylic acid such as adipic acid and sebacic acid, in addition to terephthalic acid, and ethylene glycol, hexanediol, etc. as appropriate diol components are used. Here's how. For example, U.S. Patent No. 4,129,675 describes a method for preparing low melting point copolyesters using terephthalic acid and isophthalic acid. This method is economically disadvantageous due to heat fusion at a high temperature of 190 ° C. or higher. U.S. Patent No. 4,065,439 also describes a process for preparing low melting polyesters using terephthalic acid / isophthalic acid / adipic acid (or sebacic acid) and ethylene glycol / neopentyl glycol. The polyester according to this method has a melting point of 45-60 ° C. that is so low that it is difficult to use as a wick for clothing, but also has a weak strength.

Copolymer raw materials used in the above-listed prior arts have a disadvantage of acting as a defect in the polyester molecular chain after copolymerization or acting as a structure of a molecular chain rather than a straight line, leading to a decrease in crystallinity and a decrease in strength. In the case of using such a copolyester, since the crystallinity is inferior, the non-woven fabric loses its role as a binder at a temperature above the softening point. Thus, at the temperature above the softening point, the tear property of the nonwoven fabric is significantly reduced. It is not suitable for use.

Accordingly, the present invention is to provide a polyester-based binder fiber that can be preferably applied to the manufacture of automotive interior padding products or molding nonwoven fabric in view of the above problems of the prior art.

In the research to solve the above problems, when copolymerizing polyethylene terephthalate, when a specific copolymer is used, softening behavior is hardly exhibited up to a certain melting point. The present invention has been found to be very interesting to increase the varnish and to provide excellent tensile behavior in the production of nonwoven fabrics because there is no reduction in cutting strength, thereby providing a binder fiber having almost no decrease in strength even at high temperatures.

Therefore, according to the present invention, in a polyester-based binder fiber having a high melting point component of a conventional polyethylene terephthalate and a copolyester of a low melting point component, the low melting point component is the first copolymerized during polycondensation of polyethylene terephthalate. Adipic acid / 1,4-butanediol polyol having a molecular weight of 600-2,000 obtained by reacting adipic acid with 1,4-butanediol as a component is added so that the adipic acid component is 2-30 mol% of the mole of ester in the final copolymerized polyester. In addition, a polyester-based binder fiber is provided, characterized in that the copolyester reacted by adding 1,4-butanediol to 30-50 mol% relative to the molar ester in the final copolymerized polyester as the second copolymerization component.

Hereinafter, the present invention will be described in more detail.

In general, the low melting point component of the composite fiber for a binder decreases the crystallinity by copolymerizing a rigid chain or a broken molecular chain, thereby lowering the melting point. This not only lowers the strength of the fiber due to crystallinity deterioration or disappearance, but also prevents the formation of crystals, so that no melting point exists and only the softening temperature remains. However, the softening temperature is not a narrow temperature range, such as melting point, but is generally present over a wide temperature range of 20-40 ° C. or higher. Therefore, at least 10-20 ° C. above the final temperature of the softening temperature is required for thermal bonding.

Molecular weight obtained by reacting adipic acid with 1,4-butanediol instead of directly using adipic acid as the first copolymer component in order to improve the flexibility of the copolymer polyester molecular chain which is a low melting point component of the composite fiber for binders. The reaction product of 600-2,000 is used because the by-product by the dehydration condensation side reaction of 1,4-butanediol when copolymerized with 1,4-butanediol as a diol component having strong crystallinity during polycondensation of polyethylene terephthalate To reduce the acidity of the reaction system to minimize the generation of tetrahydrofuran, which is an environmental problem when generated into the atmosphere and induces a block of adipic acid and 1,4-butanediol to induce toughness of the polymer main chain This is to obtain augmentation effect.

In the copolyester of the present invention, by using 1,4-butanediol having strong crystallinity as the second copolymerization component, crystallinity is maintained even during copolymerization, and thermal bonding can be performed even at a temperature of only 5 ° C. at a melting point. Since temperature is strong in crystallinity, it becomes possible to obtain binder fiber with little deformation.

In addition, by introducing a flexible material, such as adipic acid / 1,4-butanediol polyol having a molecular weight of 600-2,000 to increase the flowability of the molecular chain as a whole to lower the melting point without disturbing the crystallinity of 1,4-butanediol In addition to facilitating processing, it is possible to improve the elasticity due to the flexible molecular chain present in the polymer backbone, thereby achieving improved effects such as increased tearing properties and toughness when binding nonwoven fabrics.

In the present invention, when the amount of 1,4-butanediol added as the second copolymerization component is less than 30 mol% of the ester mole in the final copolyester, the fusion temperature is not high, and thus it does not act as a low melting point binder. 4-butanediol becomes a main component in the diol component, and the fusion temperature is raised again.

In addition, if the adipic acid / 1,4-butanediol polyol having a molecular weight of 600-2,000, which is the first copolymerization component, is added in an amount such that the adipic acid component is less than 2 mol% of the mole of ester in the final copolymerized polyester, The effect of increasing molecular chain flexibility cannot be obtained, and when it exceeds 30 mol%, not only the crystallinity of the copolyester is lowered but also the heat resistance is worsened.

In the polyester-based binder fiber of the present invention, the composite form of the low melting point component and the high melting point component can be either a sheath-core type or a side-by-side type. Particularly preferred composites are also cis-core.

Polyester-based binder fiber according to the present invention can be thermally bonded at a similar temperature compared to conventional binder fibers, even when the durability and form stability in a high temperature atmosphere, such as automotive interior padding products used products using conventional binder fibers The strength is maintained at room temperature, and the molding nonwoven fabric has the advantage of preventing sagging under high temperature atmosphere.

Features and other advantages of the present invention as described above will become more apparent from the following examples. However, the present invention is not limited to the following examples.

The measurement of the evaluation item shown in the following Example and the comparative example was performed by the following method.

* Copolymer mole% measurement: The additive mole% of the copolyester was dissolved in trifluoroacetic acid using a Bruker Proton nuclear magnetic resonance apparatus ( ¹ H NMR) (model name: DRX-300). It was measured by.

* Melting point and softening behavior: Measured using a differential thermal scanning calorimeter (Perkin Elmer, DSC-7) and dynamic heat characteristic meter (Perkin Elmer, DMA-) when there is no heat absorption peak, that is, no melting point 7; TMA mode) softening behavior was measured.

* Intrinsic Viscosity (IV) Measurement: The copolyester was dissolved in phenol / tetrachloroethane (50/50 by weight) to make a 0.5% by weight solution, and then measured at 35 ° C. with a Uberod viscometer.

* Measurement of room temperature adhesive strength and high temperature adhesive strength: The prepared heat-sealed nonwoven fabric was fixed at a density of 2g / ㎠ and ASTM D1424 method, the normal temperature adhesive strength was measured at 25 ° C ambient temperature, the high temperature adhesive force at 100 ° C (dry heat). .

* Touch: Relative evaluation was performed by touching.

◎: excellent, ○: good, △: normal, ×: defective

Example 1

After terephthalic acid and ethylene glycol were added to an ester reactor, the reaction was carried out by a conventional method at a temperature of 258 ° C. to prepare an oligomer having a reaction rate of 96%, and adipic acid / 1,4-butanediol polyol having a molecular weight of 1,000 was added to the oligomer. 1.6 mole% of the adipic acid component to be added in an amount of 8 mole% in the final copolymerized polyester composition, and 37 mole to make 40 mole% of the 1,4-butanediol content relative to the mole of ester in the final copolymerized polyester. % Of 1,4-butanediol was added together with a conventional transesterification catalyst and transesterified at a temperature of 230 ° C. for 1 hour. After the usual condensation polymerization catalyst was added to the thus obtained esterified oligomer, the condensation polymerization reaction was carried out by raising the temperature to 260 ° C while gradually depressurizing the final decompression degree to 0.1 mmHg.

Sheath-core polyester binder fibers having 4 denier single yarn fineness were prepared using the copolyester chip thus prepared as a cis component and a general polyethylene terephthalate chip as a core component. These fibers were cut into 51 mm of fiber length and given mechanical crimps together. Thereafter, the roller carding machine was mixed with a conventional polyethylene terephthalate at a 50:50 weight ratio, and thermally bonded for 1 minute at a temperature of 175 ° C. Table 1 shows the experimental results of the above-mentioned evaluation items.

[Examples 2 to 4 and Comparative Examples 1 to 2]

As described in Table 1, the same procedure as in Example 1 was repeated except that the copolymerization ratio of the adipic acid / 1,4-butanediol polyol having a molecular weight of 1,000 as a copolymerization component and the 1,4-butanediol was changed. The evaluation results of each example are shown in Table 1.

Comparative Example 3

After terephthalic acid and ethylene glycol were added to the ester reactor, the reaction was carried out in a conventional manner at 258 ° C. to prepare an oligomer having a reaction rate of 96%, and 35 mol% of neopentyl glycol based on the mole of polyethylene terephthalate to the oligomer. Was added to the ethylene glycol in the form of a slurry with a conventional transesterification catalyst to undergo a transesterification reaction at a temperature of 240 ℃. After the usual condensation polymerization catalyst was added to the thus obtained esterified oligomer, the condensation polymerization reaction was carried out by raising the temperature to 280 ° C while gradually reducing the pressure to a final decompression ratio of 0.1 mmHg. Binder fiber was manufactured by the method similar to Example 1 using the obtained polymer chip as a sheath component, and the performance was evaluated. The evaluation results of this example are shown in Table 1.

[Comparative Example 4]

The same procedure as in Comparative Example 3 was repeated except that 40 mol% of neopentyl glycol was used as the copolymerization component. The evaluation results of this example are shown in Table 1.

[Comparative Example 5]

The same procedure as in Comparative Example 3 was repeated except that 30 mol% of isophthalic acid was used as the copolymerization component. The evaluation results of this example are shown in Table 1.

Comparative Example 6

The same procedure as in Comparative Example 3 was repeated except that 40 mol% of isophthalic acid was used as the copolymerization component. The evaluation results of this example are shown in Table 1.

division Example Comparative example One 2 3 4 One 2 3 4 5 6 Copolymer Input Composition (mol%) P-AB ^{* 1} 1.6 3.0 4.0 6.0 9.0 2.5 - - - - BD ^{* 2} 37 28 20 5 - 8 - - - - NPG ^{* 3} - - - - - - 35 40 - - IPA ^{* 4} - - - - - - - - 30 40 Copolymerization composition (mol%) AA ^{* 5} 7.8 14.9 19.5 29.2 43.5 11.9 - - - - BD 39.5 41.0 40.5 38.5 51.0 20.0 - - - - NPG - - - - - - 30.1 34.2 - - IPA - - - - - - - - 29.8 39.7 Intrinsic viscosity (IV) 0.70 0.69 0.69 0.68 0.68 0.70 0.69 0.69 0.65 0.64 Melting Point (℃) 169 154 144 121 - 197 - - - - Softening Temperature (℃) - - - - 98 - 115 112 120 115 Room temperature adhesive force (kg) 4.5 4.7 4.8 4.7 5.0 - 2.3 2.9 1.5 2.4 High Temperature Adhesion (kg) 2.4 2.3 2.2 2.0 0.9 - 0.5 0.3 0.2 0.1 touch ◎ ◎ ◎ ◎ ◎ - △ △ × ×

week. * 1) P-AB: Adipic acid / 1,4-butanediol polyol with a molecular weight of 1,000

* 2) AA: adipic acid, * 3) BD: 1,4-butanediol

* 4) NPG: neopentyl glycol, * 5) IPA: isophthalic acid

As is evident from the above experimental results, the present invention uses a copolymer polyester having high crystallinity and little deformation at a temperature below the melting point as a cis component by introducing a molecular chain having excellent crystallinity and flexibility into the polyethylene terephthalate backbone. It provides a binder fiber, such binder fiber has the advantage of preventing the increase in toughness of the final product and the fall of the cutting strength as much as possible to provide excellent tensile behavior when manufacturing the nonwoven fabric, such that there is almost no decrease in the strength of the nonwoven fabric at high temperatures.

Claims (2)

In a polyester-based binder fiber in which a high melting point component is a conventional polyethylene terephthalate and a low melting point component is copolymerized polyester, The adipic acid component is adipic acid / 1,4-butanediol polyol having a molecular weight of 600-2,000 obtained by reacting adipic acid and 1,4-butanediol as the first copolymerization component during condensation polymerization of polyethylene terephthalate. Copolymer poly which was added to be 2-30 mol% of the mol of ester in the final copolymerized polyester, and 1,4-butanediol was added as 30-50 mol% of the mol of ester in the final copolymerized polyester as the second copolymerization component. Polyester-based binder fiber, characterized in that the ester. The polyester-based binder fiber according to claim 1, wherein the composite form is sheath-core type or side-byside type.