KR100407034B1 - Thermally adhesive polyester and binder fiber comprising it - Google Patents

Abstract

The present invention (a) the dicarboxylic acid component is composed of 80 to 50 mol% of terephthalic acid and / or its ester forming derivatives and 20 to 50 mol% of di-beta-hydroxyethylene phthalate and / or its ester forming derivatives (b) a heat-adhesive copolyester and a binder fiber containing the diol component comprising 100 to 75 mol% of ethylene glycol and 0 to 25 mol% of diethylene glycol and showing only softening behavior without melting point. The present invention relates to a binder fiber that is excellent in adhesion and feel as well as making it possible to produce improved productivity of high quality polyester nonwovens with good color.

Description

Thermal Adhesive Polyester and Binder Fiber Containing It {Thermally adhesive polyester and binder fiber comprising it}

The present invention relates to heat-adhesive binder fibers used in the production of nonwoven fabrics and padding products, and more particularly, amorphous copolyester-based polyesters that exhibit high adhesion and excellent touch when thermally bonding fibers together. It relates to a binder fiber.

In general, nonwoven fabrics and padding products for clothing are made of carding short fibers, laminating several layers of carding web products in the machine direction and the semi-machine direction, and then having inter-fiber adhesion as an adhesive material (binder). It is widely known.

There are two main methods for manufacturing such a nonwoven fabric. The first method is to dissolve an acrylic or polyvinyl alcohol-based resin in a solvent and apply the adhesive onto the surface of the nonwoven fabric. It is a method of fusion of the constituent fibers by heat treatment after mixing the binder fibers prepared by complex spinning in the in-situ or sheath-core type with a low melting point of carding.

However, the first method of dissolving and spraying an acrylic or polyvinyl alcohol-based resin in a solvent does not allow the binder to penetrate deeply to the inside of the web, but also has low compatibility with the polyester, which is environmentally contaminated by the solvent and becomes a matrix. Due to the low adhesiveness also has a disadvantage of poor touch.

The method of using the heat sealability of the binder fiber without using a solvent has a big advantage that the adhesion is completed instantly by heating, and also contributes to the rationalization of the bonding process, the reduction of personnel, and the high speed even in the field of fiber adhesion. Because of this, a lot of development and commercialization. In particular, it is needless to say that the adhesive conditions must be gentle because adhesive sewing of textile products such as garments is important because the feel, color tone, etc. of the product are important.

BACKGROUND ART Conventionally, as heat-sealable binder fibers used for the production of nonwoven fabrics, padding products, and the like, conventional polyethylene, polypropylene, polyamide, ethylene-vinyl acetate copolymer, and the like are known. However, the conventional binder fibers do not have sufficient adhesive strength, in particular, adhesive strength to the polyester-based synthetic fibers, and are not satisfactory in terms of the touch of the adhesive portion. For example, copolymerized polyamide adhesives containing polyamide 11 (nylon 11) and polyamide 12 (nylon 12), which have relatively high adhesive strength and excellent solvent resistance, have a large temperature dependency of melt viscosity and a decrease in adhesive strength during use. In addition, it is difficult to improve the feel of the adhesive part, and there is a drawback in that a yellowing phenomenon occurs due to sunlight. On the other hand, polyester-based binder fibers having a high affinity with polyester-based fibers not only have excellent adhesion, but also have good touch and daylight resistance.

The heat-sealable polyester binder fibers known to date include terephthalic acid, isophthalic acid and aliphatic dicarboxylic acid having 30 or less carbon atoms as the aromatic dicarboxylic acid component, and diethylene glycol, tetramethylene glycol, neopentyl glycol as the diol component. Mostly consisting of polyethylene glycol and the like.

For example, US Pat. No. 4,129,675 describes low-melting polyester fibers based primarily on terephthalic acid and isophthalic acid. However, these fibers are economically disadvantageous because they require temperatures of 190 ° C. or higher when thermally bonded.

U.S. Patent No. 4,166,896 describes fibers made of unsaturated polyesters prepared by copolymerizing unsaturated dicarboxylic acids and the like on low molecular weight polymerized depolymerized polyesters. This fiber also has the disadvantage of low economical efficiency, too high melting point, high crystallinity to use as an adhesive.

US Pat. No. 4,065,439 describes low melting polyester fibers using terephthalic acid / isophthalic acid / adipic acid (or sebacic acid) and ethylene glycol / neopentyl glycol, but these binder fibers have a melting point of 45 ° C. to 60 ° C. Too low a wick for clothing is difficult to use disadvantages.

When the ester derivative is synthesized using terephthalic acid and isophthalic acid as the dicarboxylic acid component, a cyclic oligomer compound having a polymerization degree of 2 is generated. Since its melting point is about 325 ° C., it is higher than the spinning temperature of general polyester fiber, thus shortening the pack exchange cycle during the spinning process. It tended to lower productivity.

In view of the above drawbacks of the conventional binder fibers, the present inventors have attempted to provide a heat-adhesive polyester-based binder fiber having excellent adhesion to the polyester to be adhered and a good touch to the bonding site after adhesion. Orso-phthalic acid) molecular structure breaks the structural regularity of the polymer backbone compared to the symmetric molecular structure of terephthalic acid constituting the usual polyethylene terephthalate, lowering the melting temperature of the polymer and crystallinity compared to conventional isophthalic acid In view of the fact that the degree of destruction is high, the resin was prepared using the acid component as terephthalic acid and phthalic anhydride. As a result, a low molecular weight cyclic compound was produced, but its melting point was 198 ° C. The productivity was improved. However, the copolyester synthesized using phthalic anhydride (or ortho-phthalic acid) is poor in the color of the obtained polymer under the same conditions as the polyethylene terephthalate polycondensation process which is heated to 270 ° C to 290 ° C under a reduced pressure of 1 mmHg or less. I found that there is a problem. This problem is caused by thermal decomposition and side reactions caused by phthalic anhydride introduced in the composition of the reaction system under high temperature and high vacuum polymerization conditions, participating in the reaction in a ring-opening reaction, a direct esterification reaction, and a transesterification reaction. Caused by the creation of a substance.

Therefore, the present invention is excellent in adhesive strength with the polyester to be adhered, and good adhesion of the adhesive site after adhesion as well as good color, heat-adhesive copolymerized polyester-based binder fiber suitable for producing a high quality polyester nonwoven fabric The purpose is to provide.

In order to achieve the above object, the present inventors have conducted various studies for the purpose of improving the color defect problem occurring in the polycondensation polymerization process of copolyester. When using di-beta-hydroxyethylene phthalate obtained by reacting phthalic anhydride or ortho-phthalic acid with ethylene glycol instead of directly as a copolymerization component, the color of the obtained copolyester is improved and the softening behavior is shown without melting point. The present invention provides the excellent fiber adhesion function in a qualitative form, and it is found that the touch of the adhesion site after adhesion is also good.

Therefore, according to the present invention, in the copolyester of polycondensation of a dicarboxylic acid component containing terephthalic acid and a diol component containing ethylene glycol, (a) the dicarboxylic acid component is a terephthalic acid and / or its ester-forming derivative 80 It consists of-50 mol% and 20-50 mol% of di-beta-hydroxyethylene phthalate and / or its ester forming derivative, (b) 100-75 mol% of ethylene glycol and 0-25 diethylene glycol A heat-adhesive copolyester is provided which is composed of mol% and shows only softening behavior without melting point.

Moreover, according to this invention, the heat-adhesive co-polyester type binder fiber containing at least one part of said polyester is provided.

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

The heat-adhesive copolyester of the present invention is a terephthalic acid and / or its ester-forming derivative (hereinafter, terephthalic acid is used to include its ester-forming derivative) as a dicarboxylic acid component. 20 to 50 mole% of di-beta-hydroxyethylene phthalate and / or its ester-forming derivatives (hereinafter, di-beta-hydroxyethylene phthalate is used to include its ester-forming derivatives). use.

When the composition ratio of terephthalic acid and di-beta-hydroxyethylene phthalate as the dicarboxylic acid component is within the above range, the obtained polymer satisfies the desired softening temperature, adhesion performance and color. If the content of di-beta-hydroxyethylene phthalate is less than 20 mol%, crystals are formed in the prepared copolyester, and the softening temperature increases, causing processing temperature to rise, and if the content exceeds 50 mol%, As the softening temperature lowering effect becomes weaker, the physical properties of the copolyester are lowered and the color becomes poor.

As the diol constituting the copolyester by the polycondensation reaction, ethylene glycol may be used alone or 25 mol% or less of diethylene glycol based on the moles of dicarboxylic acid units in addition to ethylene glycol may be used together. When the composition ratio of ethylene glycol and diethylene glycol is within the above range, the desired softening temperature, adhesion performance and processability of the obtained polymer are satisfied. If the content of diethylene glycol exceeds 25 mol% softening start temperature of the copolyester is too low below 50 ℃ is unsuitable for use as a wick for clothes and the like.

Moreover, according to this invention, a polyfunctional component can be added to a copolyester reaction system. Examples of preferred polyfunctional components for addition include polycarboxylic acids, polyols, polyoxycarboxylic acids, and the like, with the addition amount being 10 to 1,000 ppm, preferably 50 to 500 ppm relative to the copolyester component. Examples of the polyfunctional component include trimellitic acid, trimesic acid, 3,3 ', 4,4'-benzophenonetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, acid esters thereof, acid anhydrides, and the like. Derivatives, glycerin, pentaerythritol, sorbitol and the like can be used alone or in combination of two or more thereof.

When the polyfunctional component is added within the above-mentioned addition amount range, it is possible to reduce the reaction temperature and shorten the reaction time during the polycondensation of the desired copolyester, thereby improving color defects, and at the same time, workability during spinning and stretching into fibers It can be improved. If the amount of the polyfunctional component is less than 10 ppm, it is insufficient to serve as a desired crosslinking agent. If the content of the polyfunctional component is more than 1,000 ppm, the crosslinking phenomenon may cause problems during polymerization, spinning, and stretching due to rapid crosslinking. Do.

The heat adhesive copolyester according to the invention can be used as part or all of the binder fiber raw material. In-situ spinning or a composite spinning method can be used to prepare binder fibers from the copolyester of the present invention. That is, the binder fiber may be prepared by spinning with the copolyester polyester component of the present invention, or by composite spinning with other fiber-forming components. The fiber form by the composite spinning can be made into the bi-side form, and can also be made into the sheath-core form which uses the copolyester of this invention as a sheath component.

Preferably, the heat-adhesive copolyester-based binder fiber according to the present invention has no melting point, exhibits softening behavior at an adhesive processing temperature in the range of 110 ° C to 180 ° C, has excellent adhesion, soft touch, and excellent color. It is advantageous in that it can be effectively applied especially in the manufacture of polyester-based nonwovens or padded products.

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.

Measurement of the evaluation items shown in the following Examples and Comparative Examples was as follows.

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

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

* Adhesive force: The sheath-core polyester binder fiber having 4 denier single yarn fineness produced by using the prepared copolyester chip as the cis component and the conventional polyethylene terephthalate chip as the core component was cut into 51 mm of fiber length, and mechanically crimped. After impregnating together, in a roller carding machine, a non-woven fabric of 2g / 100㎠ was mixed by carding at a weight ratio of 50:50 with a conventional polyethylene terephthalate, and heat-bonded for 1 minute at a temperature of 165 ° C., followed by ASTM D1424. Measured.

* Touch: Relative evaluation was performed by touching the adhesive force measurement sample by hand.

◎ (excellent), ○ (good), △ (normal), Ⅹ (bad)

Example 1

70 mol% of di-beta-hydroxyethylene phthalate (hereinafter, abbreviated as "DEP") in an ester reactor containing polyethylene terephthalate oligomer obtained by direct esterification of terephthalic acid and ethylene glycol in a ratio shown in Table 1 After the addition of di-beta-hydroxyethylene phthalate at a rate of 30 mol%, the transesterification reaction was completed at 245 ° C. for 1 hour in the presence of manganese acetate, a common transesterification catalyst. After adding antimony trioxide which is a normal condensation polymerization catalyst, it heated up to 275 degreeC under reduced pressure so that final vacuum might be 1 mmHg or less, and the polycondensation reaction was performed. The physical properties of the copolyester obtained at this time were measured. The measurement results are shown in Table 1.

A cis-core polyester binder fiber having a single yarn fineness of 4 denier was produced by using the obtained copolymerized polyester chip as a cis component and a normal polyethylene terephthalate chip as a core component. The binder fiber was cut into 51 mm of fiber length, and mechanically crimped together, and the web was laminated in a roller carding machine at a weight ratio of 50:50 with a conventional polyethylene terephthalate, and the webs were laminated and heat-bonded for 1 minute at a temperature of 165 ° C. To produce a nonwoven fabric of 2 g / 100 cm 2. The adhesion and the touch of the prepared nonwoven fabric were measured. The measurement results are shown in Table 1.

[Examples 2 to 4 and Comparative Examples 1 to 5]

As described in Table 1, the same procedure as in Example 1 was repeated except that the copolymerization ratio of terephthalic acid, di-beta-hydroxyethylene phthalate, phthalic anhydride, isophthalic acid, ethylene glycol, diethylene glycol, and trimellitic acid was changed. It was.

division Example Comparative example One 2 3 4 One 2 3 4 5 Copolymerization composition (mol%) Terephthalic acid 70 73 75 80 82 45 70 85 80 Di-β-hydroxyethylene phthalate 30 27 25 20 18 55 - - - Phthalic anhydride - - - - - - 30 - - Isophthalic acid - - - - - - - 15 20 Ethylene glycol 100 98 92 85 100 100 100 75 95 Diethylene glycol - 2 8 15 - - - 25 5 Trimellitic acid - 150 150 150 - - - - - Polymer properties Intrinsic viscosity (IV) 0.60 0.59 0.60 0.61 0.60 0.58 0.60 0.60 0.59 Color (b) 4.5 3.0 3.5 3.0 2.5 15.0 12.0 2.2 2.0 Melting point (℃) - - - - 201 - - 182 196 Softening Temperature (℃) 112 115 108 111 - 92 110 - - Nonwoven Characteristic Adhesive force (㎏) 2.6 2.5 2.4 2.2 0.5 1.7 2.4 1.2 0.9 touch ○ ◎ ◎ ○ × △ ○ △ ×

As can be seen from the results of Table 1, the copolymerized polyesters of Examples 1 to 4 and the copolymerized polyesters of Comparative Examples 2 and 3 exhibited no softening point but only softening behavior. Examples 1 to 4 are excellent in color, adhesion, and feel, while Comparative Example 2 in which the amount of di-beta-hydroxyethylene phthalate exceeds the scope of the present invention is poor in color, adhesion, and feel, When phthalic anhydride was used, the color was poor. In addition, in the case of Comparative Example 1 in which the amount of di-beta-hydroxyethylene phthalate was less than the range of the present invention, melting point appeared, adhesion and touch were very poor, and melting point in Comparative Examples 4 and 5 using isophthalic acid. Was measured and the adhesion and touch were very poor.

As described above, the heat-adhesive binder fiber made of the copolyester according to the present invention is amorphous and exhibits only softening behavior without melting point, and lowers the adhesion temperature and processing temperature when manufacturing nonwoven fabrics compared with conventional polyester-based binder fibers. In addition to excellent productivity, excellent adhesion and feel as well as good color, it is very useful for producing high quality polyester nonwoven fabric.

Claims (5)

In the copolyester obtained by condensation polymerization of a dicarboxylic acid component containing terephthalic acid and a diol component containing ethylene glycol, (a) the dicarboxylic acid component is 80 to 50 mol% of terephthalic acid and / or its ester-forming derivative and di Beta-hydroxyethylene phthalate and / or its ester-forming derivative 20 to 50 mol%, (b) the diol component consists of 100 to 75 mol% of ethylene glycol and 0 to 25 mol% of diethylene glycol, Heat-adhesive copolyester characterized by showing only softening behavior without melting point. delete The heat-adhesive copolyester of Claim 1 which adds 10-1000 ppm polyfunctional component with respect to a polyester component. The polyfunctional component according to claim 3, wherein the polyfunctional component is trimellitic acid, trimesic acid, 3,3 ', 4,4'-benzophenonetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid and acids thereof A heat-adhesive copolyester, characterized in that one or two or more mixtures selected from the group consisting of esters, acid anhydrides, glycerin, pentaerythritol, and sorbitol. The heat-adhesive co-polyester-based binder fiber containing at least a part of the heat-adhesive co-polyester according to any one of claims 1 to 4.