JPH1112349A - Copolyester and binder yarn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copolyester for producing a binder yarn having excellent adhesiveness for providing an adhesive yarn structure excellent in heat resistance and handle and the yarn using the same. SOLUTION: This copolyester comprises an acid component composed of 60-90 mol.% of an aromatic dicarboxylic acid component and 40-10 mol.% of an aliphatic dicarboxylic acid or aliphatic lactone component and an aliphatic diol component in a substantially equimolar amount to the dicarboxylic acid component as main components, has 100-190 deg.C melting point of crystal, 10<3> -10<4> Pa dynamic complex modulus of elasticity G* obtained by retention at the temperature 20 deg.C higher than the melting point of crystal for 5 minutes followed by measurement, at 1 Hz frequency and >=105 Pa absolute value |D(G*)| of rate of change of per unit temperature of the dynamic complex modulus of elasticity when the temperature is dropped from the temperature at 10 deg.C/minute temperature reduction and crystal transition occurs. The conjugate yarn comprises the copolyester and a polymer having >=220 deg.C melting point in which the copolyester amounts to at least a part of the surface of the yarn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolyester and a heat bonding type binder fiber containing the same as a heat bonding component.

[0002]

2. Description of the Related Art In recent years, structural fibers (such as roofing materials, interior materials for automobiles, nonwoven fabrics used as base fabrics for carpets, etc., fillings for bedding products such as pillows and mattresses, and cotton structures for quilting, etc.). For the purpose of bonding the main fibers to each other, heat-bonding binder fibers are widely used.

As the main fibers, polyester fibers which are relatively inexpensive and have excellent physical properties are most often used, and polyester fibers are preferably used as a binder fiber for adhering the fibers. And a polyester fiber structure bonded using the same (see, for example, US Pat. No. 4,129,67).
No. 5 and many others).

[0004] Incidentally, since polyester-based binder fibers generally use copolyester, they often do not show a clear crystal melting point (hereinafter simply referred to as melting point).
Usually softens at 90-200 ° C. Then, heat treatment is performed at a temperature equal to or higher than the softening point and lower than the melting point of the main fibers to bond the main fibers to each other.

However, if the fibers are bonded with binder fibers that do not show a clear melting point, good fluidity cannot be obtained.
There was a problem that the bonding strength was low and the strength of the product was insufficient.

[0006] Further, when a binder fiber having no melting point is used, there is a problem that when the obtained fiber structure is used in a high-temperature atmosphere, the adhesive strength is reduced and the fiber structure is deformed.

In order to solve these problems, a heat-bonding type binder fiber made of a copolyester having a melting point has been proposed. For example, JP-A-9-12693 discloses a binder composed of a copolyester having a melting point of 130 to 200 ° C., comprising a terephthalic acid component, an ε-caprolactone component, an ethylene glycol component and a 1,4-butanediol component. A fiber is disclosed. However, although this binder fiber is excellent in heat resistance, the nonwoven fabric bonded using this binder has a hard feeling, or conversely, the fibers constituting the nonwoven fabric are loosened due to insufficient adhesive strength. There was a problem of doing.

[0008]

DISCLOSURE OF THE INVENTION The present invention relates to a copolyester which is excellent in heat resistance and adhesiveness and is suitable for obtaining a binder fiber which gives a fibrous structure such as a nonwoven fabric having a soft feel, and a copolyester suitable for obtaining a binder fiber. The purpose of the present invention is to provide a binder fiber having the above-mentioned properties, using as a heat bonding component.

[0009]

The present invention solves the above-mentioned problems, and the gist thereof is as follows. 1. An acid component comprising 60 to 90 mol% of an aromatic dicarboxylic acid component and 40 to 10 mol% of an aliphatic dicarboxylic acid component or an aliphatic lactone component and an aliphatic diol component substantially equimolar to the dicarboxylic acid component as a main component. , Melting point 100 ~ 190 ℃
After holding at a temperature 20 ° C. higher than the melting point for 5 minutes, the dynamic complex elastic modulus G * measured at a frequency of 1 Hz is 10 ³ to 10
Is ⁴ Pa, absolute value of the rate of change per unit temperature of a dynamic complex elastic modulus at the time of crystal transition temperature was lowered at a rate 10 ° C. / min from the temperature | D (G *) | in the 10 ⁵ Pa or more A copolyester, characterized in that: 2. 2. A binder fiber comprising the copolyester according to claim 1 and a polymer having a melting point of 220 ° C. or higher, wherein the copolyester is a composite fiber occupying at least a part of the fiber surface.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The copolyester of the present invention is substantially equivalent to an acid component and a dicarboxylic acid component comprising 60 to 90 mol% of an aromatic dicarboxylic acid component and 40 to 10 mol% of an aliphatic dicarboxylic acid component or an aliphatic lactone component. It must have a mole of aliphatic diol as a main component and a melting point of 100 to 190 ° C.

[0012] When the melting point is lower than 100 ° C, the adhesive strength is reduced when the bonded fiber structure is used in a high-temperature atmosphere. On the other hand, when the melting point is higher than 190 ° C, the fiber structure is thermally bonded. In this case, the bonding temperature must be high, and the main fibers are softened, the crimp is impaired, and the strength and bulkiness of the fiber structure are reduced, which is not preferable.

The ratio of the aromatic dicarboxylic acid component is 60
When the amount is less than mol%, a clear melting point is not exhibited, the crystallinity of the copolyester is reduced, and the glass transition temperature is also significantly reduced, so that practical handling becomes difficult. On the other hand, if the proportion of the aromatic dicarboxylic acid component exceeds 90 mol%, the melting point of the copolyester exceeds 190 ° C., which is not preferable.

Specific examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid,
4'-diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid and the like.

Further, specific examples of the aliphatic dicarboxylic acid include adipic acid, azelaic acid, sebacic acid, dodecandioic acid, hexadecandioic acid, eicosantioic acid and the like.

Further, aliphatic lactones include those having 4 carbon atoms.
There are ~ 11 lactones, and particularly preferred aliphatic lactones include ε-caprolactone and δ-valerolactone.

On the other hand, specific examples of the aliphatic diol include:
Ethylene glycol, 1,3-propanediol, 1,4-
Butanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, neopentyl glycol, 1,6-hexanediol, 1,9-nonanediol and the like.

The copolyester may contain other copolymer components such as a polycarboxylic acid such as trimellitic acid, pentaerythritol,
It may contain a polyol such as an ethylene oxide adduct of bisphenol A and additives such as a flame retardant, a stabilizer and a coloring agent.

The copolyester of the present invention has a melting point of 20
After holding at a high temperature for 5 minutes, the dynamic complex elastic modulus G * measured at a frequency of 1 Hz is 10 ³ to 10 ⁴ Pa, and the crystal transition occurs when the temperature is decreased from the above temperature at a rate of 10 ° C./min. Absolute value of the rate of change per unit temperature of the dynamic complex elastic modulus of
*) | Must be 10 ⁵ Pa or more.

G * represents the softness of the polymer. The larger the value, the harder the polymer is and the less likely it is to flow, and the smaller this value, the softer the polymer is and the easier it flows.

If the value of G * is less than 10 ³ Pa, the polymer flows too much, and the texture of the fibrous structure which is mixed with the main fiber as the composite binder fiber and thermally bonded becomes paper-like, which is not preferable. On the other hand, when G * exceeds 10 ⁴ Pa, the fluidity of the polymer is insufficient, so that the adhesiveness as a binder fiber becomes insufficient, and the adhesive strength of the fiber structure becomes weak, which is not preferable.

| D (G *) | represents the state of crystallization when crystallizing from the molten state. The larger the value, the faster the crystallization from the molten state and the easier the crystallization. means.

When | D (G *) | is less than 10 ⁵ Pa, substantial crystallization does not occur, and the fiber structure is deformed when the bonded fiber structure is used in a high-temperature atmosphere. Is not preferred.

The copolyester having G * and | D (G *) | can be obtained by appropriately selecting the components constituting the copolyester, the copolymerization ratio, the molecular weight, and the like.

For example, terephthalic acid is used as the aromatic dicarboxylic acid, and ethylene glycol or
In the case of a copolyester based on 1,4-butanediol, a short-chain aliphatic dicarboxylic acid such as adipic acid or ε-
When copolymerizing aliphatic lactones such as caprolactone, 10 to 40 mol% of these are used. When copolymerizing long-chain aliphatic dicarboxylic acids such as dodecane diacid and eicosane diacid, these are used in an amount of 10 to 20 mol%. It is good to copolymerize within the range.

Particularly preferred as the copolyester of the present invention are terephthalic acid and adipic acid or ε-caprolactone in a molar ratio of 90/10 to 60/40 as acid components, and ethylene glycol and 1,4 -Butanediol in a molar ratio of 80/20 to 30/70, preferably 75 /
It was used at a ratio of 25 to 50/50.

The copolyester of the present invention can be obtained, for example, as follows. First, the temperature 230-250 ℃
Under a nitrogen gas control, the esterification reaction tank in which bis (β-hydroxyethyl) terephthalate and its low polymer are present is charged with a molar ratio of terephthalic acid to ethylene glycol of 1
/1.5 slurry is continuously supplied, and the esterification reaction is carried out under the conditions of normal pressure and a residence time of 7 to 8 hours to continuously obtain an esterification reaction product having an esterification reaction rate of 95% or more.
This esterification reaction product is transferred to a polycondensation reaction vessel, a predetermined amount of a slurry of aliphatic dicarboxylic acid or aliphatic lactone and aliphatic diol is added, and at a temperature of 230 to 250 ° C., 1 to 1
The esterification reaction is performed for 2 hours.

Next, the temperature is raised to 250-280 ° C., and 0.01-13.3
The polycondensation reaction is performed under reduced pressure of hPa or less until a copolyester having an intrinsic viscosity of about 0.63 to 0.70 is obtained.

If the melt viscosity of the copolyester is too low, G * at the time of melting becomes too low, and the operability at the time of composite spinning also deteriorates. Therefore, the intrinsic viscosity should be 0.63 or more. Is desirable.

The polycondensation reaction is carried out in the presence of a polycondensation catalyst. As the polycondensation catalyst, conventionally used compounds of metals such as antimony, germanium, tin, titanium and cobalt are used.

The copolyester (low-melting copolyester) of the present invention is used as a binder fiber composed of a composite fiber with a high-melting polymer having a melting point of 220 ° C. or higher. The low-melting copolyester alone can be used as the binder fiber, but the low-melting copolyester alone has a problem in the spinnability, and when this binder fiber is used, the nonwoven fabric becomes paper-like and has a hard feeling. Or
The strength of the nonwoven fabric may be insufficient.

The high melting point polymer forming the composite fiber must have a melting point of 220 ° C. or higher, and a lower melting point polymer is preferred since the difference in melting point from the low melting point copolyester becomes small. Absent.

As specific examples of the high melting point polymer, polyethylene terephthalate, polybutylene terephthalate and polyesters based on these and nylon 66 can be used. In particular, polyethylene terephthalate and polyesters based on these are preferred in terms of strength characteristics. Is preferred.

To produce the binder fiber of the present invention,
Using the low melting point copolyester and the high melting point polymer as described above, a composite fiber is formed by a conventional method. For example, spinning speed
After compound spinning at 700-1000m / min, it is bundled in tow shape,
Using a heating roller at 60-80 ° C, stretch the film in two steps 3-5 times, crimp it with a crimper, and cut it with a fiber length of 30 with a cutter.
Cut to ~ 100 mm. However, the temperature of the sliver before entering the cutter is preferably 80 ° C. or less, and steam blowing on the crimper may be performed by checking the fusion state of the fibers inside the cutter.

The form of the conjugate fiber may be a conjugate fiber in which the low-melting copolyester occupies at least a part of the fiber surface. The concentric or eccentric core-sheath type, side-by-side type, sea-island type, or a static mixing element may be placed in a spinning pack. It can be a composite fiber or the like in which a high-melting polymer inserted and spun is dispersed in a layered or streak-like manner. The concentric core-sheath type has good yarn-making properties, and the eccentric core-sheath type or the side-by-side type has a potential crimping property. Therefore, it is preferable to select an appropriate composite form according to the application.

The binder fiber of the present invention is preferably used as a binder fiber for producing a nonwoven fabric.

In order to produce a non-woven fabric, for example, the above binder fiber and ordinary polyethylene phthalate short fiber are mixed at a predetermined ratio, and after carding, 30 to 120 in accordance with the target product of basis weight. After adjusting to g / m ² , hot air having a temperature equal to or higher than the melting point of the low-melting copolyester may be applied for 1 to 2 minutes. The hot air temperature should be equal to or higher than the melting point of the low melting point copolyester, and preferably 5 to 15 ° C. higher than the melting point.

[0038]

The copolyester of the present invention is a low-melting copolyester which is crystalline and has a distinct melting point and exhibits melt fluidity, but it is kept below a certain level. Therefore,
It is recognized that the binder fiber containing the copolyester as a heat bonding component exhibits excellent adhesiveness, and the heat bonding component does not spread so much at the time of bonding, so that the texture of a fibrous structure such as a nonwoven fabric does not become hard. In addition, after the binder fiber is once melted and bonded to the main fiber, the copolyester crystallizes quickly when the temperature is lowered, and even if the temperature is raised again, the adhesive strength is reduced to a temperature near the melting point of the copolyester. It is recognized that the physical properties and shape are not impaired even when the fiber structure is used in a high temperature atmosphere.

[0039]

Next, the present invention will be described specifically with reference to examples. In addition, the measuring method of the characteristic value in an example is as follows. (a) Intrinsic viscosity ([η]) It was determined from the solution viscosity measured at a temperature of 20 ° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent. (b) Melting point Using PerkinElmer's DSC-7 differential scanning calorimeter,
The measurement was performed at a heating rate of 20 ° C./min. (c) Copolymer composition of copolyester 0.5 g of copolyester is heated and decomposed by heating with methanol to convert the acid component into a methyl ester, and the methyl ester of the acid component and the diol component into a gas chromatograph GC manufactured by Shimadzu Corporation. It was determined quantitatively using -9A. (d) Polymer G * The polymer was molded into a 50 mm x 50 mm x 1 mm flat plate using an injection molding machine, a 20 mm diameter disk was cut out from the plate, and two sheets were stacked. Using an SR-200 model, the sample was kept at a temperature 20 ° C. higher than the melting point under a nitrogen atmosphere for 5 minutes, and then measured at a frequency of 1 Hz. (e) | D (G *) | of polymer In the above measurement of G *, the largest value was selected by differentiating the value of G * measured from a temperature 20 ° C. higher than the melting point at a temperature lowering rate of 10 ° C./min. . (f) Strong non-woven fabric A non-woven fabric with a width of 25 mm and a length of 100 mm was used, and a constant-speed elongation type tensile tester UTM-4-100 manufactured by Orientic was used.
It was measured at a pulling speed of 100 mm / min. The strength under heating was measured after the sample setting part was left in a furnace at a predetermined atmospheric temperature for 90 seconds. (g) Hand of nonwoven fabric The sensory test was conducted by 10 panelists to evaluate the following three levels. Pass if up to 7 out of 10 are 1 or 2
If 4 or more were 3, the test was rejected. 1: Soft, 2: Normal, 3: Hard

Example 1 A slurry of terephthalic acid and ethylene glycol at a molar ratio of 1 / 1.5 was continuously supplied to an esterification reactor in which bis (β-hydroxyethyl) terephthalate and its low polymer were present, and the temperature was 250 ° C. The reaction was carried out under the conditions of a temperature of 0.1 ° C. and a pressure of 0.1 MPa, and the residence time was set to 8 hours, whereby an esterified product having an esterification reaction rate of 95% was continuously obtained. 52.5 kg of this esterified product
Was transferred to a polycondensation reactor, and 31.8 kg of a slurry of adipic acid and 1,4-butanediol in a molar ratio of 60/40 was added. Antimony trioxide was used as a polycondensation catalyst in an amount of 5 × 10 ^-4 mol / acid component. Mol and tetrabutyl titanate were added at 1 × 10 ⁻⁴ mol / mol of acid component, and the esterification reaction was carried out for 1 hour while stirring at a temperature of 240 ° C. and a pressure of 0.1 MPa. Next, the temperature in the reactor was raised to 260 ° C. in 30 minutes, and the pressure in the reactor was gradually reduced to 1.2 hPa or less after 60 minutes. The polycondensation reaction was carried out for 3 hours while stirring under these conditions to obtain a copolyester. This copolyester, [η] 0.68, melting point 2
Polyethylene terephthalate at 56 ° C was spun at a spinning temperature of 270 ° C, a discharge rate of 227 g / min, and a composite weight ratio of 1/1 by a concentric core-sheath composite spinneret having 225 discharge holes using a conventional composite melt spinning apparatus. , Melt spinning so that the former becomes a sheath,
After cooling, it was wound at a speed of 700 m / min to obtain a composite undrawn yarn. The undrawn yarn is bundled into a 100,000 d tow and drawn at a drawing temperature of 62
The film was stretched at a stretching ratio of 2.0 times at the first stage and 1.2 times at the second stage at a temperature of ° C., crimped with a press-type crimper, and cut into a fiber length of 51 mm to obtain a binder fiber having a fineness of 4d. . 30% by weight of this binder fiber, fiber length 51mm, fineness 2
d) Polyethylene terephthalate fiber (main fiber) was mixed with 70% by weight, passed through a card to give a web having a basis weight of 50 g / m ² , and heat-treated at each temperature shown in Table 1 for 2 minutes to obtain a nonwoven fabric.

Examples 2 to 9 The procedure of Example 1 was repeated except that the acid component, the diol component and the nonwoven fabric forming temperature were changed according to Tables 1 and 2.

Comparative Examples 1 to 6 The same procedures as in Example 1 were carried out except that the acid component, the diol component and the nonwoven fabric forming temperature were changed according to Tables 1 and 2.

Tables 1 and 2 summarize the results of the above Examples and Comparative Examples. In Table 1, the acid components and diol components indicated by the abbreviations represent the following compounds. TPA: Terephthalic acid AD: Adipic acid ε-CL: ε-Caprolactone SE: Zehasinic acid AZ: Azelaic acid DDA: Dodecane diacid IPA: Isophthalic acid EG: Ethylene glycol BD: 1,4-butanediol

[0044]

[Table 1]

[0045]

[Table 2]

The nonwoven fabrics obtained in Examples 1 to 9 had a soft feel and exhibited good strength.

On the other hand, the comparative example has the following problem. In Comparative Example 1, the copolymerization amount of AD was too small, the melting point was high, and an adhesion temperature close to the melting point of the main fiber was required. Therefore, the shape of the nonwoven fabric was damaged, and the strength of the nonwoven fabric could not be measured. In Comparative Example 2, since the copolymerization amount of AD was too large, a clear melting point was not exhibited, and the glass transition temperature was low, so that the single yarn adhered at the time of spinning, and the spinnability was poor.
Since D (G *) | was less than 10 ⁵ Pa, it did not substantially crystallize, and the nonwoven fabric was deformed when the bonded nonwoven fabric was used in a high-temperature atmosphere at 110 ° C. In Comparative Example 3, G * was low due to the low [η] of the copolyester, and the heat bonding component spread too much during heat bonding, resulting in a hard nonwoven fabric. In Comparative Example 4, the nonwoven fabric strength was not obtained in a 110 ° C atmosphere because the melting point was too low. In Comparative Example 5,
Since G * exceeds 10 ⁴ Pa, the fluidity of the copolyester is insufficient, and sufficient nonwoven fabric strength cannot be obtained.
The strength of the nonwoven fabric in an atmosphere of ° C was not obtained. Comparative Example 6
In this case, since the [η] of the polymer is too low and G * is less than 10 ³ Pa, the fluidity of the copolyester is excessive and the nonwoven fabric becomes paper-like. Sex was also bad.

[0048]

According to the present invention, it has excellent adhesiveness,
A copolyester suitable for a binder fiber providing an adhesive fiber structure having good heat resistance and feeling and a binder fiber having the above properties are provided.

Claims (2)

[Claims] 1. An aromatic dicarboxylic acid component of 60 to 90 mol% and an aliphatic dicarboxylic acid component or an aliphatic lactone component of 40 to 10%.
After maintaining for 5 minutes at a temperature of 100-190 ° C. and a melting point of 20 ° C. higher than the crystal melting point, the main component of which is an aliphatic diol component substantially equimolar to the acid component and the dicarboxylic acid component consisting of The dynamic complex elastic modulus G * measured at a frequency of 1 Hz is 10 ³ to 10 ⁴ Pa, and the speed is 10 ° C. from the above temperature.
A copolyester characterized in that the absolute value | D (G *) | of the rate of change per unit temperature of the dynamic complex modulus at the time of a crystal transition at a temperature falling per minute is 10 ⁵ Pa or more. 2. A binder fiber comprising the copolyester according to claim 1 and a polymer having a crystalline melting point of 220 ° C. or higher, wherein the copolyester is a composite fiber occupying at least a part of the fiber surface.