JP2003155334A - Modified polyester resin and polyester fiber and polyester nonwoven fabric using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modified polyester resin mainly composed of PET, suitable for obtaining a fiber structure such as nonwoven fabric having good flexibility and a flexible polyester fiber and a nonwoven fabric composed of the polyester resin. SOLUTION: This polyester resin comprises a polyester composed of an aromatic dicarboxylic acid component mainly containing terephthalic acid and an alkylene glycol component mainly containing ethylene glycol. In the resin, a phosphorus compound having a chemical structure represented by formula (1) (wherein R1 , R2 and R3 are each a 1-6C alkyl group) is copolymerized in an amount of 0.3-1.5 mol% based on total acid component of the polyester, and a temperature (Tmax ) at which tan δ in dynamic viscoelastic measurement according to a method described in the present specification exhibits a peak is within the range of 70 to 110 deg.C.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a modified polyester resin suitable for obtaining a fiber structure having good flexibility, and a polyester fiber and a polyester non-woven fabric using the same.

[0002]

2. Description of the Related Art Polyesters, especially polyethylene terephthalate (hereinafter abbreviated as PET), are used in films or bottles because of their excellent mechanical properties, dimensional stability, weather resistance, durability and recyclability. It is widely used as a fiber for molded articles, clothing, and industrial materials. Further, in the field of non-woven fabrics, there is a recent demand for using PET fibers for the purpose of cost reduction. Conventionally, for non-woven fabrics that require flexibility,
Fibers having excellent flexibility, such as polyamide fibers, have been preferably used. However, the polyamide fiber is more expensive than the polyester fiber, and there is a problem that weather resistance and dimensional stability are inferior. Therefore, in the field of non-woven fabrics, replacement of nylon fibers with polyester fibers is being studied.

[0003]

However, among the polyester fibers, the highly flexible polytrimethylene terephthalate fiber and polybutylene terephthalate fiber have problems such as poor weather resistance and high cost.
In addition, PET fibers that satisfy the same flexibility as nylon fibers have not yet been obtained. Therefore,
The object of the present invention is a modified polyester resin suitable for obtaining a fibrous structure such as a non-woven fabric having good flexibility while being a polyester mainly composed of PET, and a soft polyester fiber and non-woven fabric comprising the same. To provide.

[0004]

The present invention solves the above problems and has the following configuration. 1. A polyester composed of an aromatic dicarboxylic acid component mainly composed of terephthalic acid and an alkylene glycol component mainly composed of ethylene glycol and having a chemical structure represented by the following formula (1) for all acid components of the polyester. The phosphorus compound contained therein is copolymerized in an amount of 0.3 to 1.5 mol%, and the temperature (T _max ) at which tan δ has a peak in the dynamic viscoelasticity measurement by the method described in the present text is 70 to 11
A polyester resin characterized by being in the range of 0 ° C.

[0005]

[Chemical 2] (In the formula, R ₁ , R ₂ and R ₃ represent hydrogen or an alkyl group having 1 to 6 carbon atoms.)

2. Polyester fiber made of the above polyester resin. 3. The above polyester fiber having an apparent initial tensile resistance of 50 cN / dtex or less. 4. A polyester non-woven fabric using any one of the above polyester fibers. 5. The above polyester nonwoven fabric having a non-woven fabric bending resistance of 60 cN or less.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The polyester resin of the present invention is a polyester composed of an aromatic dicarboxylic acid component mainly composed of terephthalic acid (hereinafter abbreviated as TPA) and an alkylene glycol component mainly composed of ethylene glycol (hereinafter abbreviated as EG). Is a copolymer of a phosphorus compound having a chemical structure represented by the following formula (1).

[0008]

[Chemical 3] (In the formula, R ₁ , R ₂ and R ₃ represent hydrogen or an alkyl group having 1 to 6 carbon atoms.)

The above phosphorus compound is copolymerized for the purpose of giving flexibility to the fiber obtained from polyester, and the copolymerization amount thereof is 0.3 to 1.5 mol based on all acid components constituting the polyester. Must be%. When the copolymerization amount is less than 0.3 mol%, the fiber obtained from the polyester does not have the desired flexibility. On the other hand, when it exceeds 1.5 mol%, the polymer becomes three-dimensional and the excellent properties of polyester are impaired, and when it is used for melt spinning, troubles such as yarn breakage frequently occur and the operability is deteriorated.

Specific examples of the above phosphorus compound used in the present invention include phosphoric acid, dimethyl phosphate, diethyl phosphate, dipropyl phosphate, dibutyl phosphate, diamyl phosphate, dihexyl phosphate, trimethyl phosphate, triethyl phosphate, tripropyl phosphate. , Tributyl phosphate, triamyl phosphate, trihexyl phosphate and the like.

In addition, in order to obtain a flexible fiber, the polyester resin of the present invention is copolymerized with the above-mentioned predetermined amount of phosphorus compound, and further, in the dynamic viscoelasticity measurement.
It is necessary that the temperature (T _max ) at which tan δ shows a peak is within the range of 70 to 110 ° C, and preferably within the range of 90 to 110 ° C. Here, the method for measuring the dynamic viscoelasticity is as follows.

[Method of measuring dynamic viscoelasticity] First, a polyester resin is melted at 275 ° C. to 285 ° C.
A molded body with a thickness of 3 mm, a thickness of 1 mm and a length of 50 mm is obtained. Then, grip 10 mm from each end of the compact with a chuck, and uniaxially stretch it so that the length between the chucks of the compact (30 mm) is 3.5 times (105 mm) in a 70 ° C temperature atmosphere. After that, heat treatment is performed at 180 ° C. for 3 minutes. Then, a sample for measurement is obtained by cutting the middle part of the stretched and heat-treated molded body to a length of 35 mm. The size of the measurement sample prepared as described above is about 1.8 mm in width,
The thickness is about 0.8 mm and the length is 35 mm. Then, the dynamic viscoelasticity of the measurement sample was measured using a rheometric viscoelasticity analyzer RSA II, frequency 1.0 rad / s, temperature 30 to 200 ° C.
Measured between. At this time, the temperature at which tan δ becomes the highest was taken as the temperature at which tan δ shows a peak (hereinafter abbreviated as Tmax).

If T _max exceeds 110 ° C., a fiber structure having good flexibility cannot be obtained. On the other hand, T _max
Is less than 70 ° C., the good physical properties peculiar to polyester are impaired, for example, the heat resistance of the polyester resin is deteriorated, the polyester resins are blocked with each other, and yarn breakage occurs during melt spinning.

The polyester resin of the present invention includes aromatic dicarboxylic acid components other than terephthalic acid such as isophthalic acid, phthalic anhydride, 5-sodium sulfoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, An aliphatic dicarboxylic acid component such as dimer acid may be copolymerized. Also, diethylene glycol,
An alkylene glycol component other than ethylene glycol such as polyethylene glycol may be copolymerized.
The dicarboxylic acid component other than terephthalic acid and the alkylene glycol component other than ethylene glycol described above may affect Tmax, and may also affect the physical properties of other polyesters. Therefore, from the viewpoint of maintaining Tmax in the range of 70 to 110 ° C and maintaining good physical properties of the polyester, the content of those components is the proportion of dicarboxylic acid components other than terephthalic acid in the total acid components of the polyester. Is x mol% and the ratio of the alkylene glycol component other than ethylene glycol to the total alcohol component of the polyester is y mol%, the value of x + y is preferably 10 or less.

Fibers can be obtained from the polyester resin of the present invention by melt spinning. However, since the polyester resin of the present invention has the above-mentioned constitution, the fibers are highly flexible. Is.

The fiber made of the polyester resin of the present invention (hereinafter referred to as the present polyester fiber) can be preferably used for producing a flexible nonwoven fabric. For that purpose, the apparent initial tensile resistance of the polyester fiber is preferably 50 cN / dtex or less. Here, the apparent initial tensile resistance as referred to in the present invention is measured as follows. First, a single yarn having a single yarn fineness d is elongated using a Tensilon UTM-4-100 type manufactured by Orientec Co., Ltd. under the conditions of a sample length of 10 mm and a pulling speed of 20 mm / min. A rising tangent line L is drawn from the stress-strain curve obtained at this time, and the elongation value on the tangent line L is 10
Read the strength value P corresponding to 0%. A value obtained by dividing this P by the single yarn fineness d is regarded as the initial tensile resistance. If the apparent initial tensile resistance exceeds 50 cN / dtex, the flexibility of the nonwoven fabric when formed into a nonwoven fabric tends to be impaired, which is not preferable.

The non-woven fabric stiffness, which is an index showing the flexibility of the non-woven fabric using the present polyester fiber, is as follows:
It is preferably 60 cN or less. Here, the non-woven fabric flexibility is based on JIS L-1096, 6.19.5 (handle rheometer method), with a basis weight of 50 g / m2, a sample width of 100 mm, and a sample length of 1
Prepare three 00 mm sample pieces (nonwoven fabric) and measure using a texture meter MODEL FM-2 manufactured by DAIEI KEIEI. 15m
A sample piece is placed on an m-width slit, and the force required when the arm pushes the sample between the slits is measured at four points in the vertical and horizontal directions on the front and back of the sample, and the total value is obtained.
This is measured for three sample pieces, and the average value is taken as the nonwoven fabric bending resistance. When the bending resistance of the non-woven fabric exceeds 60 cN, the texture of the obtained non-woven fabric tends to be felt, which is not preferable. The non-woven fabric may be either a long-fiber non-woven fabric or a short-fiber non-woven fabric, but a short-fiber non-woven fabric is preferred because a softer texture is easily obtained.

The polyester resin of the present invention can be produced, for example, by the following method. First, EG / TPA was placed in an esterification reaction tank in which bis- (β-hydroxyethyl) terephthalate and / or a low polymer thereof (hereinafter abbreviated as PET oligomer) was present at a temperature of 230 to 250 ° C. under nitrogen gas suppression. A slurry consisting of EG and TPA having a molar ratio of 1.1 to 2.0 is added, and an esterification reaction product having a reaction rate of 95% is obtained under a normal pressure with a residence time of 7 to 8 hours. This esterification reaction product is transferred to a polycondensation reaction can and the concentration is 1 to 10% by mass.
Add a predetermined amount of EG solution of phosphoric acid of, at a temperature of 230 ~ 250 ℃,
After conducting the esterification reaction for 0.5 to 2 hours, the polycondensation reaction catalyst is added, and the temperature is reduced to 250 to 28 at a reduced pressure of 0.01 to 13.3 hPa or less.
The polyester resin of the present invention can be obtained by carrying out a polycondensation reaction at 0 ° C. until the intrinsic viscosity becomes 0.5 or more, and then paying out by a conventional method. As the polycondensation catalyst, metal compounds such as antimony, germanium, tin, titanium and cobalt which have been generally used conventionally are preferable. Further, as long as the effects of the present invention are not impaired, antioxidants such as hindered phenolic compounds, cobalt compounds, fluorescent agents, color improving agents such as dyes, pigments such as titanium dioxide and cerium oxide The polyester resin may contain additives such as a light stabilizer.

When polyester fibers are produced from the polyester resin obtained as described above, polyester resin chips are dried under reduced pressure by a conventional method and then spun using a melt spinning device to obtain an undrawn yarn. Then, the obtained undrawn yarn may be drawn as necessary.

When short fibers are to be obtained, the above undrawn yarns may be bundled into a tow, drawn, drawn, preferably crimped, and then cut into short fibers. A short fiber nonwoven fabric can be used by using the short fibers thus obtained. As a method for producing a short fiber non-woven fabric, a card web can be formed using a card machine, and then the fibers can be entangled with each other by needle punching, or the fibers can be bonded with each other by performing an embossing roller treatment. .

When producing a long fiber nonwoven fabric,
The polyester resin chips may be dried under reduced pressure by a conventional method and then subjected to a known process to produce a long-fiber nonwoven fabric.

[0022]

The present inventors believe that the polyester resin of the present invention can provide polyester fibers and nonwoven fabrics having good flexibility as follows. The polyester resin of the present invention has a branched molecular chain due to the copolymerization of the phosphorus compound. When this polyester resin is melt-spun and stretched, the branched structure becomes an obstacle, the orientation of the molecules is less likely to proceed than usual, and the alignment of the molecules becomes loose. However, if the alignment of the molecules becomes too loose, the good physical properties of the polyester will be impaired, so Tmax measured by the above method
The value of should be 70-110 ℃. As a result, it becomes possible to impart flexibility without impairing the physical properties of the polyester. For the reasons as described above, the fiber using the polyester resin of the present invention becomes a fiber having a high flexibility as compared with ordinary PET fiber, and a fiber structure such as a non-woven fabric obtained from this fiber is also, It has a soft and soft texture.

[0023]

EXAMPLES Next, the present invention will be described in detail with reference to examples. In addition, the measuring method and evaluation method of each characteristic value in an Example are as follows.

(A) Intrinsic viscosity ([η]) A mixture of phenol and tetrachloroethane at a mass ratio of 1/1 was used as a measuring solvent, and the temperature was measured at 20 ° C. (b) Color tone pelletized polyester resin, using Nippon Denshoku Industries Co. color difference meter ND-Σ80 type, Hunter Lab color system b
The value was measured. It should be noted that the larger the value of b, the more yellowish it is, and the smaller it is, the stronger it is bluish. It is said that the smaller the value, the better as it is not extremely small. (c) diethylene glycol content (D%) after alkaline hydrolysis of the obtained polyester resin,
Ethylene glycol and diethylene glycol were quantified using Shimadzu gas chromatograph GC-9A, and the number was calculated as the number of moles of diethylene glycol relative to ethylene glycol. (d) Temperature at which tan δ shows a peak (Tmax) The temperature was determined by the above-described dynamic viscoelasticity measurement method. The melting temperature in melt extrusion for sample preparation is
275 in the examples for the polyester resin of the present invention.
C. and 285.degree. C. in Comparative Example 5 for PET resin.

(E) Apparent Initial Tensile Resistance of Polyester Fiber The short fiber fibers obtained in Examples and Comparative Examples were obtained as samples by the method described above.

(F) Nonwoven fabric bending resistance It was determined by the method described above. (g) Texture of non-woven fabric A sensory test by 10 panelists evaluated the following three grades. 1: Extremely soft 2: Soft 3: Normal In addition, as a reference sample (usually), the nonwoven fabric obtained in Comparative Example 5 described later was used, and 7 out of 10 people had 1 or more.
Or, if it is 2, it is determined to be acceptable.

Example 1 A slurry of TPA and EG (molar ratio TPA / TG = 1 / 1.6) was continuously supplied to an esterification reaction vessel containing PET oligomer, and the reaction was carried out under the conditions of a temperature of 250 ° C. and a pressure of 0.1 MPaG. Then, the residence time was set to 8 hours, and an esterification reaction product with a conversion of 95% was continuously obtained. 50.25 kg of this esterification reaction product was transferred to a polycondensation reaction vessel, and 7.21 kg of an EG solution of phosphoric acid having a concentration of 3% by mass was transferred.
(The phosphoric acid content is 0.75 with respect to the total acid component of the polyester.
The amount of the esterification reaction is 250
It was carried out at ℃ for 1 hour. Then, 0.73 kg of an EG solution of antimony trioxide having a concentration of 2% by mass as a polycondensation catalyst (2 × 10 −4 of antimony trioxide to 1 mol of all acid components of polyester)
Molar amount), and then the temperature inside the reaction vessel is adjusted to 30
The temperature in the reaction vessel is gradually reduced to 280 ° C in 60 minutes.
It was set to 1.2 hPa or less after a minute. The polycondensation reaction was carried out for 4 hours with stirring under these conditions, and the polyester resin was pelletized by paying out and pelletizing by a conventional method. Next, the pellet-shaped polyester resin obtained above was dried under reduced pressure and supplied to a melt spinning device at a spinning temperature of 28
At 5 ℃, spinning speed 900m / min, discharge rate 360g / min,
Melt-spinning was performed using a spinneret with a hole diameter of 0.3 mm and the number of holes was 720, and then aligned to obtain an unstretched tow of 120,000 dtex. Next, this unstretched tow was first stretched 3.3 times at a heating roller temperature of 65 ° C. and then second stretched 1.1 times at a heating roller temperature of 60 ° C. After that, heat setting was performed at a heat drum temperature of 190 ° C., mechanical crimping was performed, and then cut into a length of 51 mm to obtain short fiber polyester fibers (short polyester fibers). Furthermore, the polyester short fibers obtained above were made into a card web having a basis weight of 50 g / m ² using a card processing machine, and then subjected to an embossing roller treatment under the conditions of a temperature of 200 ° C., a speed of 4 m / min, and a linear pressure of 490 N / cm. A polyester nonwoven fabric was obtained by carrying out.

Example 2 Example 2 was repeated except that the amount of phosphoric acid added to the EG solution was changed in the polyester resin production process so that the copolymerization amount of phosphoric acid was the value shown in Table 1 below. Thus, a polyester resin and polyester short fibers and a polyester nonwoven fabric using the same were obtained.

Example 3 50.25 kg of an esterification reaction product from a PET oligomer obtained by the same method as in Example 1 was transferred to a polycondensation reaction vessel, and 7.21 kg of an EG solution of phosphoric acid having a concentration of 3% by mass (polyester) After adding 0.75 mol% of phosphoric acid to all the acid components) and 1.33 kg of diethylene glycol (amount of 5.0 mol% of diethylene glycol to 1 mol of all glycol components of the polyester), Esterification reaction at 250 ° C
I went there for 1 hour. Then, a polyester resin was obtained in the same manner as in Example 1 to obtain a polyester short fiber and a polyester nonwoven fabric.

Example 4 Example 3 was repeated except that the EG solution of phosphoric acid and the addition amount of diethylene glycol were changed during the production of the polyester resin so that the copolymerization amount of phosphoric acid and diethylene glycol would be the values shown in Table 1 below. Similarly to the above, a polyester resin and polyester short fibers and a polyester nonwoven fabric using the same were obtained.

Example 5 48.74 kg of an esterification reaction product from a PET oligomer obtained in the same manner as in Example 1 was transferred to a polycondensation reactor, and 4.80 kg of an EG solution of phosphoric acid having a concentration of 3% by mass (polyester). The amount of phosphoric acid is 5.0 mol% with respect to the total acid component of
After adding 2.19 kg of EG slurry of adipic acid having a concentration of 50% by mass (amount of adipic acid to be 3.0 mol% with respect to all acid components of polyester), esterification reaction was carried out at 250 ° C. for 1 hour. Then, a polyester resin was obtained in the same manner as in Example 1 to obtain a polyester short fiber and a polyester non-woven fabric.

Example 6 50.25 kg of an esterification reaction product from a PET oligomer obtained by the same method as in Example 1 was transferred to a polycondensation reaction vessel, and 5.00 kg of an EG solution of triethyl phosphate having a concentration of 10% by mass.
(The amount of triethyl phosphate is 1.1 mol% with respect to the total acid component of the polyester), and the average molecular weight is 2000.
After adding 3.84 kg of polyethylene glycol (amount occupying 8% by mass to the mass of polyester), the esterification reaction was carried out at 250 ° C. for 1 hour. After that, Example 1
A polyester resin was obtained in the same manner as in 1. to obtain polyester short fibers and a polyester nonwoven fabric.

Comparative Example 1 Example 3 was repeated except that the EG solution of phosphoric acid and the addition amount of diethylene glycol were changed during the production of the polyester resin so that the copolymerization amount of phosphoric acid and diethylene glycol would be the values shown in Table 1 below. Similarly to the above, a polyester resin and polyester short fibers and a polyester nonwoven fabric using the same were obtained.

Comparative Example 2 In the same manner as in Example 1 except that the addition amount of the phosphoric acid EG solution during the production of the polyester resin was changed so that the copolymerization amount of phosphoric acid became the value shown in Table 1 below. , Polyester resin was obtained. In this example, fiberization was not possible.

Comparative Example 3 Example 3 was repeated except that the amount of phosphoric acid added to the EG solution during the production of the polyester resin was changed so that the amount of phosphoric acid copolymerized was the value shown in Table 1 below. , A polyester resin and polyester short fibers and a polyester nonwoven fabric using the same were obtained.

Comparative Example 4 The same as Example 5 except that the EG solution of phosphoric acid and the addition amount of adipic acid were changed so that the copolymerization amount of phosphoric acid and adipic acid became the values shown in Table 1 below. went. In this example, fiberization was not possible.

Comparative Example 5 Polyester short fibers (that is, PET short fibers) and polyester non-woven fabric (that is, PET non-woven fabric) were obtained in the same manner as in Example 1 using ordinary PET resin.

The characteristics of the polyester resin, polyester fiber, and polyester nonwoven fabric in the above Examples and Comparative Examples are summarized in Table 1 below.

[0039]

[Table 1]

As is clear from Table 1, the polyester resins of the present invention obtained in Examples 1 to 6 had an intrinsic viscosity sufficient to be formed into fibers and had a good color tone. Further, since the polyester fibers obtained from these polyester resins are flexible fibers having a low apparent initial tensile resistance, it is possible to obtain a soft non-woven fabric having a low non-woven fabric bending resistance. On the other hand, in Comparative Example 1, since the amount of copolymerization of the phosphorus compound was too small, the apparent initial tensile resistance of the fiber was high and the flexibility was inferior, so that the non-woven fabric had a high bending resistance and a soft texture. I couldn't do that. Further, in Comparative Example 2, the copolymerization amount of the phosphorus compound was too large, so that the polyester resin became three-dimensional, and as a result, many yarn breakages occurred during spinning, and fibers could not be obtained. It was In Comparative Example 3, since the Tmax of the obtained polyester resin exceeds 110 ° C., the apparent initial tensile resistance of the fiber is high and the flexibility is inferior, so that the non-woven fabric has a high bending resistance and a soft texture. I couldn't get it. In Comparative Example 4, since the Tmax of the obtained polyester resin was less than 70 ° C., many fiber breakages occurred during spinning, and fibers could not be obtained.

[0041]

EFFECTS OF THE INVENTION According to the present invention, a modified polyester resin which is a polyester mainly composed of PET and is suitable for obtaining a fiber structure having good flexibility, and a flexible polyester fiber using the same Can be provided.
Further, the polyester non-woven fabric obtained from the polyester fiber has a soft texture, and can be suitably used for applications requiring flexibility such as non-woven fabrics for interlining.

Continued front page    F-term (reference) 4J029 AA02 AA03 AB01 AB07 AC02                       AD01 AE02 BA03 BH03 CB06A                       DC07 FA02 HA01 HB01                 4L035 BB31 EE08 FF05 GG01                 4L047 AA21 AB02 AB03 AB10 BA08                       CB01 CB04

Claims (5)

[Claims] 1. A polyester comprising an aromatic dicarboxylic acid component containing terephthalic acid as a main component and an alkylene glycol component containing ethylene glycol as a main component, wherein all the acid components of the polyester are represented by the following formula (1): 0.3-1.5 mol% of phosphorus compound having the indicated chemical structure
A polyester resin characterized in that the temperature (T _max ) at which tan δ has a peak in the dynamic viscoelasticity measurement according to the method described herein is in the range of 70 to 110 ° C. . [Chemical 1] (In the formula, R ₁ , R ₂ and R ₃ represent hydrogen or an alkyl group having 1 to 6 carbon atoms.) 2. A polyester fiber comprising the polyester resin according to claim 1. 3. The polyester fiber according to claim 2, which has an apparent initial tensile resistance of 50 cN / dtex or less. 4. A polyester non-woven fabric comprising the polyester fiber according to claim 2 or 3. 5. The polyester nonwoven fabric according to claim 4, which has a non-woven fabric bending resistance of 60 cN or less.