JP2003119270A - Copolyester and heat bonding fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat bonding fiber excellent in heat bonding properties at a low temperature to a polyethylene terephthalate and other polyester fibers and capable of providing a nonwoven fabric excellent in hue. SOLUTION: Starting materials for polymerization comprising an alkylene glycol terephthalate and an oligomer thereof and an alkylene glycol isophthalate and an oligomer thereof are heated in a glycol together with a specific titanium compound and a specific phosphorus compound as catalysts to give a deposit. Using the thus-obtained deposit, a copolyester comprising 50-90 mole% of an ethylene terephthalate unit and 5-50 mole% of an ethylene isophthalate unit, both based on the all recurring units of the copolyester, and having an intrinsic viscosity in the range of 0.35-0.60 is obtained. This copolyester is employed as an adhesive component in a heat bonding fiber.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a copolyester and a heat-adhesive fiber, and more specifically, a copolyester having an excellent color tone obtained by using a catalyst for producing a polyester containing a specific titanium compound and phosphorus compound. And a heat-bondable fiber.

[0002]

2. Description of the Related Art In recent years, in the use of non-woven fabrics, with the increase in the proportion of polyester fibers used as constituent fibers, a polyester-based polymer having good thermal adhesiveness with the polyester fibers is used as a thermal adhesive component. There is an increasing demand for heat-adhesive fibers that do.

Further, in the production of non-woven fabrics and the like, from the viewpoints of production efficiency and energy saving, a method of adhering by a heat treatment at a relatively low temperature of 100 to 150 ° C. for a short time is often used. A polyester-based heat-bondable fiber having good properties is desired.

It is well known that when polymerizing such a polyester polymer, the reaction rate and the quality of the obtained polyester are greatly influenced by the kind of catalyst used in the polycondensation reaction step. As a polycondensation catalyst for polyethylene terephthalate, antimony compounds are most widely used because of having excellent polycondensation catalyst performance and obtaining a polyester having a good color tone.

However, when an antimony compound is used as a polycondensation catalyst, when polyester is continuously melt-spun for a long period of time, foreign matter (hereinafter, sometimes simply referred to as die foreign matter) adheres and deposits around the mouth of the die. However, there is a problem that the process becomes unstable due to this, and there is also a problem that the obtained fiber has a dark hue peculiar to antimony. However, there was a problem that antimony was eluted.

It has been proposed to use a titanium compound such as titanium tetrabutoxide as a polycondensation catalyst other than the antimony compound. However, when such a titanium compound is used, the above-mentioned deposition of foreign matter on the spinneret is prevented. Although the problem of moldability due to the problem can be solved, a new problem arises in that the obtained polyester itself is colored yellow and the melt thermal stability is poor.

In order to solve the above coloring problem, it is generally practiced to add a cobalt compound to polyester to suppress yellowing. It is true that the color tone (b value) of the polyester can be improved by adding the cobalt compound, but the melt heat stability of the polyester is lowered by the addition of the cobalt compound, and the decomposition of the polymer easily occurs. There is.

Further, as another titanium compound, Japanese Patent Publication No.
No. 8-2229 discloses titanium hydroxide and Japanese Patent Publication No.
JP-A 7-26597 discloses the use of α-titanic acid as a catalyst for polyester production. However, in the former method, it is not easy to pulverize titanium hydroxide into powder, while in the latter method, α-titanic acid is likely to be deteriorated, so that its storage and handling are not easy,
Therefore, neither is suitable for industrial use, and it is also difficult to obtain a polymer having a good color tone (b value).

Further, JP-B-59-46258 discloses a product obtained by reacting a titanium compound with trimellitic acid, and JP-A-58-38722 discloses a titanium compound and a phosphite. It is disclosed that each of the products obtained by reacting with and is used as a catalyst for producing polyester. Indeed, according to this method,
Although the melt heat stability of polyester is improved to some extent, the color tone of the obtained polymer is not sufficient,
Therefore, further improvement in polymer color tone is desired.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a non-woven fabric which has excellent low-temperature thermal adhesiveness to polyester fibers such as polyethylene terephthalate and which does not contain antimony and has an excellent hue. It is to provide an adhesive fiber.

[0011]

Means for Solving the Problems As a result of intensive studies made by the present inventors in view of the above-mentioned prior art in order to achieve the above-mentioned objects,
The present invention has been completed.

That is, an object of the present invention is to use an alkylene glycol ester of terephthalic acid and its low polymer and an alkylene glycol ester of isophthalic acid and its low polymer as polymerization starting materials, and polycondense them in the presence of a catalyst. When obtaining a copolyester polymer, a titanium compound represented by the following formula (I) and a phosphorus compound represented by the following formula (II) are used as the catalyst in the number of moles of phosphorus element relative to the number of moles of titanium element ( (P / Ti) is in the range of 1 to 4 and 50 to 90 mol% of ethylene terephthalate units are used, based on the total repeating units of the copolymerized polyester, using the precipitate obtained by heating in glycol. Ethylene isophthalate units occupy 5 to 50 mol%, and the intrinsic viscosity is in the range of 0.35 to 0.60. Characterized in that to give the ester is achieved by the manufacturing method of the copolymerized polyester.

[0013]

[Chemical 4]

[0014]

[Chemical 5]

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

In the copolyester of the present invention, it is necessary that the terephthalic acid component accounts for 50 to 90 mol% based on the total dicarboxylic acid components constituting the polyester. When the content of the terephthalic acid component is less than 50 mol%, the obtained polymer or fiber is likely to cause fusion or sticking. On the other hand, if it exceeds 90 mol%, the texture becomes hard and the adhesiveness also deteriorates.

Further, if the isophthalic acid component is less than 5 mol% based on the total dicarboxylic acid components constituting the copolyester, the thermal adhesiveness is deteriorated, which is not preferable. Further, if it exceeds 50 mol%, it is disadvantageous in terms of cost.
Fusion is likely to occur during the production of the copolymerized polyester chip and further the resulting heat-bondable fiber. The isophthalic acid component is preferably 7 mol% or more and 50 mol% or less, more preferably 14 mol% or more and 45 mol% or less.

Further, the copolyester of the present invention is
It is necessary that the ethylene glycol component accounts for 90 mol% or more based on the total glycol components constituting the copolyester. When the content of the ethylene glycol component is less than 90 mol%, the cost becomes high, which is not preferable. The preferred range of the ethylene glycol component is 95
It is at least mol%.

The intrinsic viscosity of the copolymerized polyester of the present invention (measured in an orthochlorophenol solvent at 35 ° C.) is
It is necessary to be in the range of 0.35 to 0.60. If the intrinsic viscosity is lower than 0.35, the mechanical properties of the copolyester will be deteriorated, and the strength of the fused portion in the finally obtained heat-bonded product such as nonwoven fabric will be insufficient. On the other hand, when it is higher than 0.60, the fluidity of the polymer tends to be low, and the thermal adhesion performance tends to be low.
The intrinsic viscosity of the copolyester is 0.40 to 0.60.
Is preferable, and the range of 0.50 to 0.60 is more preferable.

The copolymerized polyester of the present invention may be copolymerized with a component other than the terephthalic acid component, the isophthalic acid component and the ethylene glycol component within a range that does not impair the characteristics thereof, preferably within a range of 5 mol% or less. Naphthalene dicarboxylic acid, orthophthalic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, benzophenone dicarboxylic acid,
Aromatic dicarboxylic acids such as phenylindanedicarboxylic acid, 5-sulfoxyisophthalic acid metal salt, 5-sulfoxyisophthalic acid phosphonium salt, adipic acid, heptanedioic acid, octanedioic acid, azelaic acid, sebacic acid, undecanedioic acid, Aliphatic dicarboxylic acids such as dodecanedioic acid, cyclohexanedicarboxylic acids, alicyclic dicarboxylic acids such as dichlorohexanedimethylenedicarboxylic acid, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol , Aliphatic glycols such as neopentylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene glycol, cyclohexanediol, cyclohexa Alicyclic glycols dimethanol, etc., o- xylylene glycol, m- xylylene glycol, p- xylylene glycol, 1,4-bis (2-
Hydroxyethoxy) benzene, 1,4-bis (2-hydroxyethoxyethoxy) benzene, 4,4′-bis (2-hydroxyethoxy) biphenyl, 4,4′-bis (2-hydroxyethoxyethoxy) biphenyl,
2,2-bis [4- (2-hydroxyethoxy) phenyl] propane, 2,2-bis [4- (2-hydroxyethoxyethoxy) phenyl] propane, 1,3-bis (2-hydroxyethoxy) benzene, 1,3-bis (2-hydroxyethoxyethoxy) benzene, 1,2
-Bis (2-hydroxyethoxy) benzene, 1,2-
Bis (2-hydroxyethoxyethoxy) benzene,
Aromatic glycols such as 4,4′-bis (2-hydroxyethoxy) diphenyl sulfone and 4,4′-bis (2-hydroxyethoxyethoxy) diphenyl sulfone, hydroquinone, 2,2-bis (4-hydroxyphenyl)
Diphenols such as propane, resorcin, catechol, dihydroxynaphthalene, dihydroxybiphenyl, dihydroxydiphenyl sulfone and the like can be mentioned. These may be used alone or in combination of two or more.

In the copolymerized polyester used in the present invention, if necessary, a small amount of additives such as lubricants, pigments,
Dyes, antioxidants, solid-phase polymerization accelerators, optical brighteners, antistatic agents, antibacterial agents, ultraviolet absorbers, light stabilizers, heat stabilizers,
It may contain a light-shielding agent, a matting agent and the like.

The copolymerized polyester of the present invention comprises a titanium compound represented by the following general formula (I) and a phosphorus compound represented by the following general formula (II) in the number of moles of phosphorus element relative to the number of moles of titanium element (P / Ti) needs to be polymerized using a titanium / phosphorus reaction product reacted in a range of 1 to 4.

[0023]

[Chemical 6]

[0024]

[Chemical 7]

If the number of moles of phosphorus element relative to the number of moles of titanium element (P / Ti) is less than 1, the resulting polyester may have poor color tone and its heat resistance may deteriorate, which is not preferable. If greater than 4,
The catalytic activity for the polyester-forming reaction becomes insufficient, which is not preferable. The number of moles of phosphorus element relative to the number of moles of titanium element (P / Ti) is preferably in the range of 1.2 to 3.5, and more preferably in the range of 1.5 to 3.0.

Further, the catalyst preparation of the titanium compound component (I) and the phosphorus compound component (II) needs to be heated and reacted in ethylene glycol. The reaction method is, for example, the phosphorus compound (II). Component and ethylene glycol are mixed, a part or all of the phosphorus compound component is dissolved in a solvent, and the titanium compound component (I) is added to this mixed solution.
Is added dropwise, and the reaction system is heated to a temperature of 0 to 200 ° C. for 30 minutes or more, preferably 60 to 150 ° C. for 40 to 90 minutes. In this reaction, there is no particular restriction on the reaction pressure, and it is usually carried out under normal pressure.

Examples of the titanium compound represented by the above formula (I) include titanium tetraalkoxides such as titanium tetrabutoxide, titanium tetraisopropoxide, titanium tetrapropoxide and titanium tetraethoxide, and octaalkyl trititanate. , Hexaalkyl dititanate, alkyl titanate, titanium acetate and the like.

In the phosphorus compound represented by the above formula (II), when p is 0 in the formula, for example, phenylphosphonic acid, methylphosphonic acid, ethylphosphonic acid, propylphosphonic acid, isopropylphosphonic acid, butylphosphonic acid. Acid, tolylphosphonic acid, xylylphosphonic acid, biphenylphosphonic acid, naphthylphosphonic acid, anthrylphosphonic acid, 2-carboxyphenylphosphonic acid, 3-carboxyphenylphosphonic acid, 4-carboxyphenylphosphonic acid, 2,3-di Carboxyphenylphosphonic acid,
2,4-dicarboxyphenylphosphonic acid, 2,5-dicarboxyphenylphosphonic acid, 2,6-dicarboxyphenylphosphonic acid, 3,4-dicarboxyphenylphosphonic acid, 3,5-dicarboxyphenylphosphonic acid,
2,3,4-tricarboxyphenylphosphonic acid, 2,
3,5-tricarboxyphenylphosphonic acid, 2,3
6-tricarboxyphenylphosphonic acid, 2,4,5-
Examples thereof include tricarboxyphenylphosphonic acid and 2,4,6-tricarboxyphenylphosphonic acid, and among them, monoarylphosphonic acid is preferable.

When p is 1, for example, monomethyl phosphate, monoethyl phosphate, monotrimethyl phosphate, mono-n-butyl phosphate, monohexyl phosphate, monoheptyl phosphate, monononyl phosphate, monodecyl phosphate, monododecyl phosphate. , Monophenyl phosphate, monobenzyl phosphate, mono (4-dodecyl) phenyl phosphate, mono (4-methylphenyl) phosphate, mono (4-ethylphenyl) phosphate, mono (4-propylphenyl) phosphate, mono (4-dodecyl) (Phenyl) phosphate, monotolyl phosphate, monoxylyl phosphate, monobiphenyl phosphate, mononaphthyl phosphate, monoanthryl phosphate, etc. It is.

A method in which the titanium compound represented by the above formula (1) is used by previously reacting it with a polyvalent carboxylic acid of the following formula (III) and / or its anhydride is also preferably used.
In that case, the reaction molar ratio of the titanium compound to the polycarboxylic acid and / or its anhydride is preferably in the range of (2: 1) to (2: 5). A particularly preferred range is (1: 1) to (1:
2).

[0031]

[Chemical 8]

The amount of titanium element contained in the copolyester of the present invention is preferably in the range of 2 to 40 mmol% based on the total dicarboxylic acid component. If the amount of titanium element is less than 2 mmol%, the polymerization reaction will be delayed.
When it exceeds 40 mmol%, the color tone of the obtained polyester may be poor and the heat resistance thereof may be deteriorated, which is not preferable. The amount of titanium element is 5 to 35 mmol%
Is preferable, and a range of 10 to 30 mmol% is more preferable.

The heat-adhesive fiber of the present invention is a composite fiber comprising at least one polyester selected from the group consisting of polyethylene terephthalate type polyester, polybutylene terephthalate type polyester or polytrimethylene terephthalate type polyester and the above copolymerized polyester. Is preferred.

Here, the polyethylene terephthalate-based polyester refers to 90 repeating units of ethylene terephthalate based on all repeating units of the polyester.
Mol% or more, preferably 95 mol% or more, and the polytrimethylene terephthalate-based polyester is 90 mol% or more, preferably 9 mol% of trimethylene terephthalate repeating units, based on all repeating units of the polyester.
A polybutylene terephthalate-based polyester of 5 mol% or more refers to a polyester in which the butylene terephthalate repeating units account for 90 mol% or more, preferably 95 mol% or more, based on all the repeating units of the polyester. Another copolymerization component may be copolymerized in these polyesters as long as the characteristics of the polyester itself are not impaired.

Polyethylene terephthalate type polyester, polytrimethylene terephthalate type polyester and polybutylene terephthalate type polyester used in the heat-adhesive fiber of the present invention are also preferably polymerized with a titanium catalyst, and particularly polyethylene terephthalate type polyester is used. It is preferable to use the titanium compound used in the polyester for heat-bonding fibers of the present invention described above.

The intrinsic viscosity of the polyethylene terephthalate type polyester, polytrimethylene terephthalate type polyester and polybutylene terephthalate type polyester used in the heat-adhesive fiber of the present invention is usually 0. 50-1.00
What is used.

In the thermoadhesive fiber of the present invention, the copolyester provided as an adhesive component needs to be exposed at least on the surface of the composite fiber, and is exposed so as to occupy 40% or more of the surface. Is preferred. If the copolyester is not exposed on the surface of the composite fiber, the adhesive effect cannot be obtained, which is unsuitable. The area ratio of the copolymerized polyester in any cross section of the conjugate fiber is preferably 10 to 70%, more preferably 30.
˜70%, particularly preferably 30 to 50%.

The composite fiber having such a composite form may be in the form of a core-sheath type composite fiber, an eccentric core-sheath type composite fiber, a side-by-side type composite fiber or the like. In the case of a core-sheath type composite fiber, a copolymerized polyester is arranged as a sheath component, and polyethylene terephthalate-based polyester,
A core-sheath type composite fiber in which either a polybutylene terephthalate polyester or a polytrimethylene terephthalate polyester is arranged as a core component is particularly preferable. Further, in the case of the core-sheath type composite fiber, when the copolyester is used as the core component, it is necessary to make the core eccentric so that the core component is at least exposed on the fiber surface. Further, it can be preferably used also as a side-by-side type composite fiber.

The heat-adhesive fiber of the present invention may be made into a non-woven fabric after forming an aggregate of only the heat-adhesive fiber, but it is usually combined with another fiber containing 10 wt% or more of the heat-adhesive fiber. It is used as a non-woven fabric after forming a mixed fiber aggregate of.

The heat-adhesive fiber of the present invention is suitable for use in producing a nonwoven fabric by heat-bonding polyester fiber, but it is also used for other heat-adhesive applications such as cushioning material and cotton wadding. It can be widely used.

[0041]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In addition, the part in an Example shows a weight part. Various characteristics were evaluated by the following methods. (1) Intrinsic viscosity: Orthochlorophenol was used as a solvent at 35 ° C., and the relative viscosity was determined by a conventional method. (2) Color tone (L value and b value): 290 for polymer sample
Melt for 10 minutes under vacuum at ℃, form a plate with a thickness of 3.0 ± 1.0 mm on an aluminum plate, then immediately quench in ice water, and dry the plate at 160 ℃ for 1 hour. The plate was placed on a white standard plate for color difference meter adjustment, and the Hunter L value and b value on the plate surface were measured using a Hunter type color difference meter CR-200 manufactured by Minolta.
The L value indicates the lightness, the larger the value, the higher the lightness, and the larger the value, the higher the degree of yellow coloring. (3) Metal element content: fluorescent X-ray measuring device 3 manufactured by Rigaku Corporation
270 was used. (4) Adhesive strength: In accordance with the method described in JIS L1096, the tensile breaking strength was measured at a gripping interval of 10 cm and an extension rate of 20 cm / min. The adhesive strength was a value obtained by dividing the tensile breaking strength by the weight of the test piece.

Reference Example 1 In 131 parts by weight of ethylene glycol, 3.6 parts by weight of phenylphosphonic acid was heated at 120 ° C. for 10 minutes to be dissolved. 134.5 parts by weight of this ethylene glycol solution was further added with 40 parts of ethylene glycol.
After adding parts by weight, titanium tetrabutoxide 3.
8 parts by weight were dissolved. The resulting reaction system was heated at 120 ° C for 6
After stirring for 0 minutes, the titanium compound was reacted with phenylphosphonic acid to obtain a white slurry of the catalyst containing the reaction product. The titanium content of this catalyst slurry was 0.3% by weight.

[Reference Example 2] 0.8 part by weight of trimellitic anhydride was dissolved in 2.5 parts by weight of ethylene glycol, and 0.7 part by weight of titanium tetrabutoxide (based on the molar amount of trimellitic acid anhydride) was added to this solution. 0.5 mol%) was added dropwise, and the reaction system was kept in air at 80 ° C. for 60 minutes under atmospheric pressure to react titanium tetrabutoxide with trimellitic anhydride to age the reaction product. After that, the reaction system was cooled to room temperature, 15 parts by weight of acetone was added thereto, and the precipitate was separated into No. It was filtered with 5 filter paper, collected, and dried at a temperature of 100 ° C. for 2 hours. The titanium content of the obtained reaction product was 11.2% by weight.

Then, 3.6 parts by weight of phenylphosphonic acid was dissolved in 131 parts by weight of ethylene glycol by heating at 120 ° C. for 10 minutes. This ethylene glycol solution 13
After further adding 40 parts by weight of ethylene glycol to 4.5 parts by weight, 5.0 parts by weight of the above titanium compound was dissolved therein. The resulting reaction system is stirred at 120 ° C. for 60 minutes to react the titanium compound with phenylphosphonic acid,
A white slurry of catalyst containing the reaction product was obtained. The titanium content of this catalyst slurry was 0.3% by weight.

Reference Example 3 3.5 parts by weight of mono-n-butyl phosphate were dissolved in 131 parts by weight of ethylene glycol by heating at 120 ° C. for 10 minutes. After adding 40 parts by weight of ethylene glycol to 134.5 parts by weight of this ethylene glycol solution, 3.8 parts by weight of titanium tetrabutoxide was dissolved therein. The reaction system obtained was 1
The mixture was stirred at 20 ° C. for 60 minutes to react the titanium compound with mono-n-butyl phosphate to obtain a white slurry of the catalyst containing the reaction product. The titanium content of this catalyst slurry was 0.3% by weight.

[Reference Example 4] 0.8 parts by weight of trimellitic anhydride was dissolved in 2.5 parts by weight of ethylene glycol, and 0.7 part by weight of titanium tetrabutoxide was added to the solution. 0.5 mol% based on the molar amount of meritic acid) was added dropwise, and the reaction system was kept at 80 ° C. for 60 minutes in air under atmospheric pressure to react titanium tetrabutoxide with trimellitic acid anhydride, and the reaction The product was aged. After that, the reaction system was cooled to room temperature, 15 parts by weight of acetone was added thereto, and the precipitate was separated into No. It was filtered with 5 filter paper, collected, and dried at a temperature of 100 ° C. for 2 hours. The titanium content of the obtained reaction product was 11.2% by weight.

Next, 3.5 parts by weight of mono-n-butyl phosphate was added to 120 parts of 131 parts by weight of ethylene glycol.
It melt | dissolved by heating at 10 degreeC for 10 minutes. After adding 40 parts by weight of ethylene glycol to 134.5 parts by weight of this ethylene glycol solution, 5.0 parts of the above titanium compound was added thereto.
Part by weight was dissolved. The obtained reaction system is 60 at 120 ° C.
After stirring for a minute, the titanium compound was reacted with mono-n-butyl phosphate to obtain a white slurry of the catalyst containing the reaction product. The titanium content of this catalyst slurry was 0.3% by weight.

[Example 1] 60 parts of terephthalic acid, 40 parts of isophthalic acid and 45 parts of ethylene glycol were subjected to an esterification reaction at 240 ° C, and the obtained reaction product was placed in a polycondensation flask equipped with a rectification column. 1.7 parts of a 20% titanium oxide ethylene glycol slurry, 1.92 parts by weight of the slurry prepared in Reference Example 1 as a polycondensation catalyst (20 mmol in terms of titanium atomic weight based on the total amount of terephthalic acid and isophthalic acid) %) And 0.0001 part by weight of terazol blue as a color-adjusting agent, and the resulting reaction system was subjected to polycondensation reaction under high vacuum at a temperature of 285 ° C. and 30 Pa, and was made into chips according to a conventional method. The polymer obtained had an intrinsic viscosity of 0.570. The results are shown in Table 1.

Examples 2 to 4 and Comparative Example 1 Example 1 was repeated except that the catalyst was changed as shown in Table 1.

[Reference Example 5] Polyethylene terephthalate having an intrinsic viscosity of 0.62 was obtained in the same manner as in Example 1, except that 100 parts of terephthalic acid was used without using isophthalic acid.

[Example 5] The copolymer polyester obtained by the operation of Example 1 was used as a sheath component, and the polyethylene terephthalate produced in Reference Example 5 was used as a core component, and sheath / core = 5.
It was melted and discharged from the core-sheath type composite spinneret at 0/50 (weight ratio), and taken out at a speed of 800 m / min. At this time, the melting temperature of the sheath component was 240 ° C and the melting temperature of the core component was 280 ° C.

The undrawn yarn thus obtained was drawn at a drawing temperature of 60 ° C. and a draw ratio of 3.0, and crimped at a crimp ratio of 10%. Then, the obtained crimped yarn was cut into a length of 51 mm to obtain 5 dtex of heat-bondable fiber.

The area ratio of the copolyester in the cross section of the fiber was 50%, and there was no sticking between the fibers during spinning and stretching, and stable production was possible.

20 parts by weight of this heat-adhesive fiber and 80 parts by weight of polyethylene terephthalate short fiber having a cut length of 51 mm were mixed and heat-bonded at 130 ° C. to obtain a nonwoven fabric. The heat-adhesive fibers did not stick to the device during the production of the nonwoven fabric, and the processability was good. The adhesive strength of the obtained nonwoven fabric was 195 N / g.

[Example 6] The same procedure as in Example 5 was repeated except that the polyester obtained in Example 4 was used as the heat-bonding polyester for the sheath. The heat-adhesive fibers did not stick to the device during the production of the nonwoven fabric, and the processability was good. The adhesive strength of the obtained non-woven fabric was 200 N / g.

[Example 7] The same procedure as in Example 5 was repeated except that the core polyester was changed to polybutylene terephthalate. The heat-adhesive fibers did not stick to the device during the production of the nonwoven fabric, and the processability was good. The adhesive strength of the obtained non-woven fabric was 165 N / g.

Example 8 Example 8 was repeated except that the core polyester was changed to polytrimethylene terephthalate. The heat-adhesive fibers did not stick to the device during the production of the nonwoven fabric, and the processability was good. The adhesive strength of the obtained nonwoven fabric was 180 N / g.

[0058]

[Table 1]

[0059]

EFFECT OF THE INVENTION The copolyester of the present invention has a good hue, and the obtained fiber has excellent thermal adhesiveness at low temperature to polyester fibers such as polyethylene terephthalate and, at the same time, has a good texture of the obtained nonwoven fabric. It is also excellent and can be usefully used in a wide range of non-woven fabric applications.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J029 AA03 AB04 AC02 AD01 AE02                       BA03 CB05A CB06A HA01                       HB01 HB02 JB131 JC571                       JC581 JC591 JC751 JF321                       KB02 KE02 KE03                 4L041 AA20 BA02 BA05 BA21 BA49                       BD03 BD11 CA06 CA07 CA12                       CA62 DD05 EE01

Claims (12)

[Claims] 1. A copolyester polymer prepared by polycondensing an alkylene glycol ester of terephthalic acid and / or a low polymer thereof and an alkylene glycol ester of isophthalic acid and / or a low polymer thereof in the presence of a catalyst. In obtaining the compound, a titanium compound represented by the following formula (I) and a phosphorus compound represented by the following formula (II) are used as the catalyst, and the number of moles of phosphorus element relative to the number of moles of titanium element (P / Ti) Is 1
The content of ethylene terephthalate units occupies 50 to 90 mol% based on the total repeating units of the copolyester, using the precipitate obtained by heating in glycol, and the amount is 5 to 50 mol. %, Ethylene isophthalate units account for 0.35 to 0.
A method for producing a copolyester, characterized in that a copolyester having a range of 60 is obtained. [Chemical 1] [Chemical 2] 2. The method for producing a copolyester according to claim 1, wherein a phosphorus compound in which the value of p in the formula (II) is 0 is used. 3. The method for producing a copolyester according to claim 2, wherein the phosphorus compound is a monoarylphosphonic acid. 4. The method for producing a copolyester according to claim 1, wherein a phosphorus compound in which the value of p in the formula (II) is 1 is used. 5. The method for producing a copolyester according to claim 4, wherein the phosphorus compound is a monoalkyl phosphate. 6. The copolyester according to claim 1, wherein the titanium compound of the formula (I) uses a catalyst for producing a polyester selected from titanium tetraalkoxides, octaalkyl trititanates, and hexaalkyl dititanates. Manufacturing method. 7. A titanium compound of the formula (I) is previously reacted with a polyvalent carboxylic acid of the following general formula (III) and / or its acid anhydride in a reaction molar ratio of (2: 1) to (2: 5). The method for producing a copolyester according to claim 1, wherein the composition is reacted with the phosphorus compound of the formula (II) after the reaction. [Chemical 3] 8. Obtained by the method of claim 1,
The content of titanium element is 2 to 40 based on the total dicarboxylic acid component.
Copolyester in the range of millimole%. 9. A thermoadhesive fiber comprising the copolymerized polyester according to claim 8 disposed so as to be exposed at least on the surface thereof. 10. The heat-adhesive fiber according to claim 9, wherein the heat-adhesive fiber is a core-sheath type composite fiber in which polyethylene terephthalate-based polyester is arranged in a core component and copolymerized polyester is arranged in a sheath component. 11. The heat-adhesive fiber according to claim 9, wherein the heat-adhesive fiber is a core-sheath type composite fiber in which polytrimethylene terephthalate-based polyester is arranged in a core component and copolymerized polyester is arranged in a sheath component. . 12. The heat-adhesive fiber according to claim 9, wherein the heat-adhesive fiber is a core-sheath type composite fiber in which polybutylene terephthalate-based polyester is arranged in the core component and copolymerized polyester is arranged in the sheath component.