TW201811860A - Polyester fiber using binder having advanced adhesive strength characterized in that the core portion is formed of a common polyester resin and the sheath portion is formed of low-melting-point copolymer polyester resin through the use 2-methyl-1,3-propanediol - Google Patents

Abstract

The present invention relates to a polyester fiber using binder having advanced adhesive strength. The polyester fiber for a binder is formed of a sheath portion and a core portion, characterized in that the aforementioned core portion is formed of a common polyester resin and the sheath portion is formed of low-melting-point copolymer polyester resin through the use of 2-methyl-1,3-propanediol, the adhesive force is greater than 50kgf at room temperature, and the adhesive force is greater than 4kgf at a high-temperature.

Description

   Polyester fiber for bonding agent for improving bonding strength   

The present invention relates to a polyester fiber for an adhesive agent for improving the adhesive strength, and more particularly to a polyester fiber for an adhesive agent for improving the adhesive strength that maintains a high adhesive force at normal temperature and high temperature.

The hot-melt adhesive fibers used in order to form the filaments or multiple short fibers of a non-woven web or sheet should have a heat-bonding processing temperature of 140 to 150 ° C and should have the same properties as ordinary polyterephthalic acid. Fibers have similar glass transition temperatures, but to do this, the crystalline structure in the polymer needs to be removed to make the polymer structure into an amorphous state.

For this reason, in the process of synthesizing polyester resins, a representative method is to copolymerize terephthalic acid with isophthalic acid as a copolymer component, but at this time, based on the mole of the ester, add 20 ~ 45 mol% isophthalic acid, because the polyester resin thus synthesized has an amorphous molecular structure, and the final melting point will be in the temperature range of 145 ~ 180 ° C, so it can be used as a polyester fiber for binders.

U.S. Granted Patent No. 4,129,675 discloses a low-melting polyester adhesive with terephthalic acid and isophthalic acid as the main components. However, it is not economical because it needs to reach a temperature of 200 ° C or higher when performing thermal bonding. .

U.S. Patent No. 4,166,896 discloses a method for preparing unsaturated polyester by copolymerizing unsaturated dicarboxylic acid or the like in a low molecular weight of depolymerized polyester. However, the fibers in the above patent are not only economically low, but also have excessively high melting points. And high crystallinity makes it unsuitable for use as a binder.

U.S. Patent No. 4,065,439 discloses a low melting polyester obtained by using terephthalic acid / isophthalic acid / adipic acid (or sebacic acid) and ethylene glycol / neopentyl glycol. The melting point is 45 ° C to 60 ° C. Because the melting point is too low, it is not only difficult to use as a core for clothing, but also has poor morphological stability under high temperature conditions.

On the other hand, Korean Laid-Open Patent No. 2001-11548 provides polycondensation of a dicarboxylic acid component of terephthalic acid and phthalic anhydride and a diol component of ethylene glycol and diethylene glycol to achieve a polyether component with polyester. A binder for polyester fibers that has excellent adhesion and does not cause yellowing after being bonded. However, the above-mentioned adhesive has the disadvantage that the reaction mechanism is complicated because phthalic anhydride is directly used. The color of the copolymer polyester is defective, and it is necessary to lower the polycondensation temperature. In addition, such a low-temperature polycondensation reaction lowers work efficiency.

In addition, the conventional polyester-based adhesive fiber maintains adhesiveness at normal temperature, but the adhesiveness decreases sharply at high temperature, so that it cannot be used in various industrial fields.

The present invention has been made in order to solve the problems of the prior art as described above, and an object thereof is to provide a polyester fiber for an adhesive that improves the adhesive strength while maintaining a high adhesive force at normal temperature and high temperature.

Furthermore, an object of the present invention is to provide a polyester fiber for a binder that improves the bonding strength, that is, a low-melting copolymer polyester resin having a glass transition temperature of 60 ° C. or higher, which can be used for the binder in the stretching process. The low glass transition temperature of polyester fibers improves the problem of close contact between adjacent fibers.

The present invention provides polyester fibers for a binder that improve the bonding strength. The polyester fibers for a binder are formed of a sheath portion and a core portion, wherein the core portion is formed of an ordinary polyester resin, and the sheath portion is formed of a low-melting copolymer. It is formed from an ester resin. The constituents of the low-melting-point copolymer polyester resin include an acid component composed of terephthalic acid or an ester-forming derivative thereof, and 2-methyl-1,3-propanediol (MPD). A diol component composed of ethylene glycol (DEG) and ethylene glycol (EG). In the above diol component, if the mole percentage of 2-methyl-1,3-propanediol is A, the mole of diethylene glycol is When the percentage is set to B, the following formulas (1) and (2) are satisfied, the adhesive force at room temperature is 50 kgf or more, the adhesive force at high temperature is 4 kgf or more, formula (1): 30 A + B 50, formula (2): 1.0 A / B.

The present invention provides polyester fibers for a binder that improve the bonding strength. The polyester fibers for a binder are formed of a sheath portion and a core portion, wherein the core portion is formed of an ordinary polyester resin, and the sheath portion is formed of a low-melting copolymer. It is formed from an ester resin, and the forming component of the low-melting copolymer polyester resin includes an acid component composed of terephthalic acid and isophthalic acid or an ester-forming derivative thereof, and 2-methyl-1,3-propanediol. A diol component consisting of 1, 2 glycol, and ethylene glycol. If the molar percentage of isophthalic acid or its ester-forming derivative is A in the acid component, the 2- When the molar percentage of methyl-1,3-propanediol is set to B and the molar percentage of diethylene glycol is set to C, then the formulas (1) to (3) are satisfied, and the adhesive force at room temperature is 50 kgf or more, and the adhesive force at high temperature is Above 4kgf, formula (1): 40 A + B + C 60, formula (2): 0.5 A / B 2.0, formula (3): 1.0 B / C.

In addition, the polyester fiber for a binder for improving the bonding strength provided by the present invention is characterized in that, in the low-melting-point copolymer polyester resin, 2-methyl-1,3-propanediol accounts for 20 to 40 of the diol component. In terms of mole percentage, diethylene glycol accounts for 10 to 20 mole percent in the diol component.

In addition, the polyester fiber for a binder for improving the bonding strength provided by the present invention is characterized in that, in the low-melting-point copolymer polyester resin, isophthalic acid or its ester-forming derivative accounts for 10 to 10 of the acid component. 20 mol%, 2-methyl-1,3-propanediol occupies 10 to 40 mol% in the diol component, and diethylene glycol occupies 10 to 20 mol% in the diol component.

In addition, the polyester fiber for a binder for improving the bonding strength provided by the present invention is characterized in that the softening temperature of the low-melting-point copolymer polyester resin is 110 to 130 ° C.

In addition, the polyester fiber for a binder for improving the bonding strength provided by the present invention is characterized in that the glass transition temperature of the low-melting copolymer polyester resin is 60 ° C to 70 ° C.

The present invention also provides a non-woven fabric comprising the polyester fiber for a binder described above.

As described above, the adhesive polyester fiber for improving the adhesive strength of the present invention has the effect of having a high adhesive force at normal temperature and maintaining a predetermined adhesive force at a high temperature.

In addition, the present invention has the effect that the glass transition temperature (Tg) of the low-melting-point copolymer polyester resin forming the sheath portion of the polyester fiber for the binder is 60 ° C. or higher, thereby improving the stability of the spinning process. It can be stored for a long time or can prevent the adhesion between fibers during transportation.

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

The terms "about", "substantially", and the like used in the present invention refer to meanings that adopt corresponding values or are close to corresponding values when suggesting inherent manufacturing tolerances and material tolerances for the mentioned meanings, This disclosure is intended to prevent unlawful offenders from using the disclosure in an accurate or absolute value to help understand the invention.

The present invention relates to a polyester fiber for an adhesive formed by a sheath portion and a core portion, and belongs to the composite fiber in which the core portion is formed of an ordinary polyester resin and the sheath portion is formed of a low-melting point copolymer polyester resin.

Any of the common polyester resins forming the core may be used, but preferably, a polyethylene terephthalate (PET) resin made of terephthalic acid and ethylene glycol is used.

In the present invention, the low melting point copolymer polyester resin forming the sheath portion is a copolymer polyester resin using 2-methyl-1,3-propanediol as a diol component, and is divided into a first embodiment and a second embodiment. example.

In the first embodiment, the composite fiber forming the sheath portion is a polyester resin formed of an acid component and a diol component that is composed of terephthalic acid or an ester-forming derivative thereof. The diol component is composed of 2-methyl-1,3-propanediol, diethylene glycol, and ethylene glycol. In the second embodiment, the composite fiber forming the sheath portion is composed of the following acid component and the following diol A polyester resin composed of components, that is, an acid component composed of terephthalic acid (TPA) and isophthalic acid (IPA) or an ester-forming derivative thereof, and 2-methyl-1,3 -A polyester resin formed of a diol component composed of propylene glycol (MPD), diethylene glycol (DEG), and ethylene glycol (EG) is a composite fiber forming a sheath portion.

The polyester fiber for a binder for improving the bonding strength in the first embodiment will be described.

In the 2-methyl-1,3-propanediol used in the sheath portion of the composite fiber of the present invention, since the methyl group is bonded to the second carbon, the rotation of the polymer main chain can be facilitated, and the polymer can function as a polymer. The terminal part acts the same, thereby expanding the free space between the main chains and increasing the possibility of flow of the entire molecular chain. This makes the polymer amorphous and has the same thermal characteristics as isophthalic acid. The soft molecular chain existing in the polymer main chain is used to improve the elasticity, thereby improving the tearing properties when bonding the non-woven fabric.

That is, 2-methyl-1,3-propanediol rotates the main chain of the polymerized resin by including a methyl group (-CH ₃ ) as a side chain in an ethylene chain combined with ethylene terephthalate. The method ensures space, so that the softening point (Ts) and / or the glass transition temperature (Tg) can be adjusted by inducing an increase in the degree of freedom of the main chain and a decrease in the crystallinity of the resin. This can have the same effect as the case where an asymmetric aromatic cycloisophthalic acid (IPA) is used conventionally to reduce the crystallinity of the crystalline polyester resin.

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

In the first embodiment, the softening temperature and the softening temperature of the low melting point copolymer polyester resin are adjusted by adjusting the content of 2-methyl-1,3-propanediol (MPD) and diethylene glycol (DEG) used as the diol component. Glass transition temperature (Tg).

In addition, in order to improve the adhesion of the low-melting-point copolymer polyester resin used in the present invention, it is preferable that in the low-melting-point copolymer polyester resin, 2-methyl-1,3-propanediol is contained in the diol component. It accounts for 20 to 40 mole percent, and diethylene glycol accounts for 10 to 20 mole percent of the diol component. In more detail, in the above diol component, if the mole percentage of 2-methyl-1,3-propanediol is set Is A, and if the molar percentage of diethylene glycol is set to B, the following formula (1), formula (2), and formula (1) are satisfied: 30 A + B 50, formula (2): 1.0 A / B.

As shown in the above formula (1), when the total content (A + B) of 2-methyl-1,3-propanediol and diethylene glycol is less than 30 mol% of the diol component, the high-temperature adhesion may be high. If it is lower than 50 mol%, the physical properties of the low-melting copolymer polyester resin may decrease.

As shown in the above formula (2), when A / B is less than 1.0, that is, when the content of diethylene glycol is greater than 2-methyl-1,3-propanediol, since the glass transition temperature (Tg) decreases, It may be restricted in use.

The polyester fiber for a binder for improving the bonding strength of the second embodiment described above.

In the second embodiment, by adjusting isophthalic acid (IPA) or its ester-forming derivative contained in the acid component and 2-methyl-1,3-propanediol (MPD) contained in the diol component, Diethylene glycol (DEG) content to adjust the softening temperature and glass transition temperature (Tg) of the low-melting copolymer polyester resin forming the sheath portion.

In addition, in order to improve the adhesion of the low-melting-point copolymer polyester resin of the second embodiment, it is preferable that, in the low-melting-point copolymer polyester resin, isophthalic acid or an ester-forming derivative thereof has an acid component. It accounts for 10-20 mole percent, 2-methyl-1,3-propanediol accounts for 10-40 mole percent of the diol component, and diethylene glycol accounts for 10-20 mole percent of the diol ingredient. In more detail, In the acid component, if the molar percentage of isophthalic acid or its ester-forming derivative is A, and the molar percentage of 2-methyl-1,3-propanediol in the diol component is B, When the molar percentage of diethylene glycol is set to C, then formulas (1) to (3) are satisfied, and formula (1): 40 A + B + C 60, formula (2): 0.5 A / B 2.0, formula (3): 1.0 B / C.

As shown in the above formula (1), the total content (A + B + C) of isophthalic acid or its ester-forming derivative, 2-methyl-1,3-propanediol, and diethylene glycol is less than 40 moles. In the case of a percentage, the high-temperature adhesive force may decrease, and in the case of more than 60 mol%, the physical properties of the low-melting copolymer polyester resin may decrease.

As shown in the above formula (2), when A / B is less than 0.5, that is, the content of 2-methyl-1,3-propanediol is compared with isophthalic acid or its ester-forming derivative. When it is more than 2 times, the high-temperature adhesion may be reduced. When A / B is greater than 2.0, that is, the content of isophthalic acid or its ester-forming derivative is 2-methyl-1, When the content of 3-propanediol is twice or more, the economy may be reduced, and the cyclic compound that is a side reaction product in the polymerization step may have high productivity. The optimum value of the A / B value as the above formula (2) is 1.0 A / B 2.0.

As shown in the above formula (3), when the B / C is less than 1.0, that is, when the content of diethylene glycol is more than 2-methyl-1,3-propanediol, the glass transition temperature (Tg) decreases. It may be restricted in use, and the morphological stability may decrease when it is made into a non-woven fabric.

When the content of the 2-methyl-1,3-propanediol is 20 mol% or more in the diol component, it has the effect of suppressing the production of a cyclic compound as a side reaction product in the polyester polymerization step.

As described above, in the low-melting-point copolymer polyester resin for forming the sheath portion of the composite fiber of the present invention in which the content of 2-methyl-1,3-propanediol and diethylene glycol is adjusted, the softening temperature is adjusted to 110 ~ 130 ° C, glass transition temperature is 60 ° C to 70 ° C, inherent viscosity is 0.55dl / g or more, so it has excellent physical properties.

As described above, the polyester fiber for improving the adhesive strength of the present invention using a low-melting-point copolymer polyester resin to form a sheath portion has a normal-temperature adhesive force of 50 kgf or more, has excellent adhesive force, and achieves a high-temperature adhesive force of 4 kgf. Above, therefore, the adhesive force above the prescribed level is maintained at high temperature.

As described above, the polyester fiber for adhesives for improving the adhesive strength of the present invention can not only be thermally bonded at a temperature suitable for the existing adhesive fibers and low temperatures in a similar range, but also because the glass transition temperature can reach 60 ° C or more. Therefore, even if it is required to maintain durability and morphological stability in a high-temperature atmosphere, such as products for automotive interiors, it maintains its strength and has the ability to prevent sagging in a high-temperature atmosphere in non-woven fabrics for molding. Advantages, it can be used for non-woven fabrics for a variety of purposes.

Hereinafter, examples of the method for producing the polyester fiber for an adhesive for improving the adhesive strength of the present invention will be described, but the present invention is not limited to the examples.

Examples 1 to 3

Polyterephthalic acid was used as the core portion, and a low-melting-point copolymer polyester resin was used as the sheath portion, and the polyester fiber for an adhesive agent for improving the bonding strength of the present invention was prepared through a common composite spinning process.

The above-mentioned low-melting-point copolymer polyester resin is prepared as follows: terephthalic acid (TPA) and ethylene glycol (EG) are put into an ester reaction tank, and a common polymerization reaction is performed at a temperature of 258 ° C to prepare a reaction A PET oligomer with a rate of about 96%. In the prepared polyterephthalic acid (PET), 2-methyl-1,3-propanediol (MPD) and diethylene glycol (DEG) were mixed at a content ratio shown in Table 1 below, and a transesterification reaction was added. The catalyst is used to carry out the transesterification reaction at a temperature of 250 ± 2 ° C. Subsequently, a polycondensation reaction catalyst is added to the obtained reaction mixture, and the final temperature and pressure in the reaction tank are adjusted to 280 ± 2 ° C. and 0.1 mmHg, respectively, and a polycondensation reaction is performed.

Examples 4 to 6

Polyterephthalic acid was used as the core portion and a low-melting point copolymer polyester resin was used as the sheath portion. The polyester fiber for an adhesive agent for improving the bonding strength of the present invention was prepared through a common composite spinning process.

The above-mentioned low-melting-point copolymer polyester resin is prepared as follows: terephthalic acid (TPA) and ethylene glycol (EG) are put into an ester reaction tank, and a common polymerization reaction is performed at a temperature of 258 ° C to prepare a reaction A PET oligomer with a rate of about 96%. In the prepared polyterephthalic acid (PET), 2-methyl-1,3-propanediol (MPD), diethylene glycol (DEG), and isophthalic acid (DEG) were mixed at a content ratio shown in Table 1 below. isophthalic acid (IPA), by adding a transesterification reaction catalyst, the transesterification reaction is performed at a temperature of 250 ± 2 ° C. Subsequently, a polycondensation reaction catalyst is added to the obtained reaction mixture, and the final temperature and pressure in the reaction tank are adjusted to 280 ± 2 ° C. and 0.1 mmHg, respectively, and a polycondensation reaction is performed.

Comparative Example 1

As in Example 1, polyterephthalic acid was used as the core portion and a low-melting point copolymer polyester resin was used as the sheath portion. However, in the low-melting point copolymer polyester resin of the sheath portion, terephthalic acid was used as the acid component ( TPA), the glycol component contains 30 mole percent of diethylene glycol (DEG) and 70 mole percent of ethylene glycol (EG).

Comparative Example 2

In the same manner as in Example 4, polytetraphthalic acid was used as the core portion and the low-melting point copolymer polyester resin was used as the sheath portion. However, in the low-melting point copolymer polyester resin of the sheath portion, 70 mol% of the acid component was contained. Terephthalic acid (TPA), 30 mole percent isophthalic acid (IPA), the diol component has 15 mole percent of diethylene glycol (DEG), and 85 mole percent of ethylene glycol (EG).

The following physical properties of the low-melting-point copolymer polyester resin and the polyester fiber for a binder prepared in the above examples and comparative examples were measured, and the results are shown in Table 2 below:

(1) Measure the softening point (Ts) and glass transition temperature (Tg)

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

(2) Determination of intrinsic viscosity (IV)

The polyester resins obtained in the examples and comparative examples were each dissolved at a concentration of 0.5% by weight in a solution in which phenol and tetrachloroethane were mixed at a weight ratio of 1: 1, and then at 35 ° C using an Uberloth viscosity meter. Determine the intrinsic viscosity (IV) at a temperature of.

(3) Determination of adhesion at room temperature and adhesion at high temperature

Non-woven fabrics with a fixed density of 2 g / 100 cm ² were prepared by hot-melting the polyester fibers of the examples and comparative examples, and measured at 25 ± 0.5 ° C (normal temperature) and 100 ± 0.5 ° C (high temperature) according to ASTM D1424. Non-woven fabric cohesion at temperatures

(4) High temperature shrinkage

After the polyester fiber for a binder is prepared from short fibers, it is prepared into a cylindrical shape by carding. After applying heat at 170 ° C for 3 minutes, the reduced volume was measured. The existing volume is 330 cm ^3. If the volume is reduced more, it can be evaluated as poor morphological stability. Generally, when it is 250 cm ³ or less, the level of morphological stability is reduced, and when it is 280 cm ³ or more, it can be evaluated as excellent.

As shown in Table 2 above, in Examples 1 to 6, it can be seen that the softening point of the low-melting-point copolymer polyester resin of the present invention is 110 to 130 ° C, and has excellent low-melting point characteristics. The glass transition temperature (Tg) is uniform. It was 60 ° C or higher, which was higher than Comparative Example 1, and it was found that it was very excellent.

In addition, as for the adhesive force of the polyester fiber for adhesives, in Examples 1 to 6 and Comparative Examples, the room temperature adhesive force was 55 kfg or more, and all were determined to be excellent. However, in terms of high temperature adhesive force, in the Examples, From 1 to Example 3, it was 4.0 kfg or more, and it was found that it was very superior to 1.8 kfg of Comparative Example 1 and 3.2 kfg of Comparative Example 2.

In addition, in the preparation of non-woven fabrics, Examples 1 to 6 and Comparative Examples all achieved high-temperature shrinkage of 250 cm ³ or more, and it was found that a good level was achieved. In particular, those with high 2-methyl-1,3-propanediol content It was found that the high-temperature shrinkage of Example 1 was 285 cm ³ and was very excellent.

Claims (7)

A polyester fiber for an adhesive agent for improving the bonding strength. The polyester fiber for the adhesive agent is formed of a sheath portion and a core portion, wherein the core portion is formed of an ordinary polyester resin, and the sheath portion is formed of a low melting point copolymer polyester resin. The forming component of the low-melting copolymer polyester resin includes an acid component composed of terephthalic acid or an ester-forming derivative thereof, and 2-methyl-1,3-propanediol, diethylene glycol, and ethylene glycol. For a diol component having an alcohol composition, in the above diol component, if the molar percentage of 2-methyl-1,3-propanediol is set to A and the molar percentage of diethylene glycol is set to B, the following formula ( 1), formula (2), the adhesive force at room temperature is above 50kgf, the adhesive force at high temperature is above 4kgf, formula (1): 30 A + B 50, formula (2): 1.0 A / B. A polyester fiber for an adhesive agent for improving the bonding strength. The polyester fiber for the adhesive agent is formed of a sheath portion and a core portion, wherein the core portion is formed of an ordinary polyester resin, and the sheath portion is formed of a low melting point copolymer polyester resin. The forming component of the low-melting copolymer polyester resin includes an acid component composed of terephthalic acid and isophthalic acid or an ester-forming derivative thereof, and 2-methyl-1,3-propanediol, For a diol component composed of glycol and ethylene glycol, if the molar percentage of isophthalic acid or its ester-forming derivative in the acid component is A, and the 2-methyl group in the diol component is When the molar percentage of -1,3-propanediol is set to B and the molar percentage of diethylene glycol is set to C, then the formulas (1) to (3) are satisfied, and the adhesive force at room temperature is 50 kgf or more, and the adhesive force at high temperature is 4 kgf or more. ,     The polyester fiber for an adhesive agent for improving the adhesive strength according to item 1 of the scope of the patent application, wherein in the low-melting copolymer polyester resin, 2-methyl-1,3-propanediol is contained in a diol component. It accounts for 20 to 40 mole percent, and diethylene glycol accounts for 10 to 20 mole percent of the diol component.         The polyester fiber for an adhesive for improving the bonding strength according to item 2 of the scope of the patent application, wherein in the low-melting copolymer polyester resin, isophthalic acid or an ester-forming derivative thereof is acidic. The composition accounts for 10 to 20 mole percent, 2-methyl-1,3-propanediol accounts for 10 to 40 mole percent of the glycol component, and diethylene glycol accounts for 10 to 20 mole percent of the glycol component.         The polyester fiber for an adhesive agent for improving the bonding strength according to item 1 or item 2 of the scope of the patent application, wherein the softening temperature of the low-melting-point copolymer polyester resin is 110 to 130 ° C.         The polyester fiber for an adhesive agent for improving the bonding strength according to item 1 or item 2 of the scope of the patent application, wherein the glass transition temperature of the low-melting copolymer polyester resin is 60 ° C to 70 ° C.         A non-woven fabric, comprising the polyester fiber for a binder as described in the first or the second item of the patent application.