JP2001254230A - Latent crimping polyester conjugate fiber and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide latent crimping polyester conjugate fibers which can uniformly be cut, when processed into a nonwoven fabric, can give the nonwoven fabric having excellent elasticity, and does not need a worry for endocrine disruption which affects human bodies. SOLUTION: This latent crimping polyester conjugate fiber comprises a polyester A copolymerized with a metal sulfonate group-having aromatic dicarboxylic acid in an amount of 3 to 7 mol.% based on the total amount of the acid components and containing polyethylene terephthalate as a main constituting component and a polyester B containing ethylene terephthalate units as main repeating units, has a fiber strength of <=3.0 cN/dtex, a free shrinkage rate of >=15% on a 170 deg.C dry heat treatment, and a latent crimping performance for developing spiral crimps of >70 crimps/25 mm after the thermal treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endocrine system which improves the cutability of a non-woven fabric having excellent elasticity, which is composed of latently crimpable polyester fiber, improves the productivity of the non-woven fabric, and further has an adverse effect on the human body. TECHNICAL FIELD The present invention relates to a latently crimpable polyester composite fiber which becomes a nonwoven fabric which is not likely to disturb, and a method for producing the same.

[0002]

2. Description of the Related Art Nonwoven fabrics using polyester fibers have excellent properties such as functionality and recyclability.
Used in a wide range of applications. In particular, a nonwoven fabric using a polyester fiber having latent crimpability has excellent stretchability and elastic recovery properties, and is used as a sanitary material application or a patch material application.

[0003] Generally, in the case of producing a non-woven fabric using latently crimpable polyester fiber, the short fiber is made into a web with a card, entangled with the short fiber by needle punching or spunlace, and then heated at 140 to 180 ° C. Heat treatment is performed to develop crimps, and then the pieces are cut to a predetermined size. At the time of cutting the nonwoven fabric, the fibers have elasticity due to the appearance of micro-crimp, so that the fibers are elongated due to the stress of the blade at the time of cutting. As a result, the cutting property is reduced, and the single yarn jumps out from the cut surface, so that uniform cutting cannot be performed. However, elasticity is the most indispensable performance for current sanitary material applications and adhesive material applications, and there is an issue of improving cutability while having elasticity.

[0004] As a non-woven fabric fiber, for example, Patent No. 27
No. 03294 discloses that 2 to 10 mol% of isophthalic acid (hereinafter abbreviated as IPA) and 1 mol% or more and 3 mol% of an aromatic dicarboxylic acid having a metal sulfonate group.
A latently crimpable conjugate short fiber composed of a polyester copolymerized in a range of less than and a polyester mainly composed of ethylene terephthalate is disclosed. However, when the amount of the metal sulfonate group-containing monomer is less than 3 mol%, the fiber strength is increased, so that the cutability is reduced, and the single yarn jumps out from the cut surface of the nonwoven fabric, so that uniform cutting cannot be performed.
Further, when the copolymerization amount with isophthalic acid is increased, the fiber strength can be reduced, but there is a problem such as a decrease in spinnability due to a decrease in the melting point of the polyester.

[0005] In recent years, the problem of endocrine disrupting substances that have an adverse effect on the human body has been taken up, and the interest of society has been increasing. In particular, in the use of sanitary materials and patches that come into direct contact with the human body, However, there is an increasing need for fibers that are not concerned with endocrine disrupting properties.

For example, Japanese Patent Application Laid-Open No. 10-204726 discloses a polyester A mainly composed of polyethylene terephthalate and a polyester B obtained by copolymerizing an ethylene oxide adduct of IPA and bisphenol A (hereinafter abbreviated as BAEO). A latently crimpable polyester composite fiber is disclosed. From the composite fiber using this copolymer component, a nonwoven fabric having sufficient elasticity is obtained,
BAEO is a derivative of bisphenol A, which is an endocrine disrupting substance, and there is a concern about the same problem, and it is not preferable for use as a sanitary material or a patch for directly contacting the human body.

Further, as described above, when producing a nonwoven fabric having elasticity, heat treatment at 140 to 180 ° C. is performed to develop crimp, thereby imparting elasticity. Generally, the heat treatment temperature at which crimping of the nonwoven fabric is developed can be controlled by the tension heat treatment temperature in the drawing step of the conjugate fiber.

For example, Japanese Patent Application Laid-Open No. 62-78214 discloses a polyester composite fiber comprising a polyester A obtained by copolymerizing 3 to 6 mol% of a structural unit having a metal sulfonate group, and a polyester B mainly comprising polyethylene terephthalate. It is disclosed that the tension heat treatment temperature in the stretching step is preferably from 120 to 170 ° C. However, when the tension heat treatment temperature is increased, in order to obtain a nonwoven fabric having satisfactory elasticity, it is necessary to increase the heat treatment temperature of the nonwoven fabric or to slow the heat treatment speed, and in terms of cost and productivity. It becomes a problem.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves such drawbacks of the latently crimpable polyester composite fiber, and does not cause the single yarn to jump out in the cutting process of the nonwoven fabric, thereby enabling uniform cutting. It is a technical problem to provide a latently crimpable polyester composite fiber and a method for producing the same, which can provide a nonwoven fabric having excellent elasticity and also have no problem of an endocrine disrupting substance that adversely affects the human body. Is what you do.

[0010]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve such problems, and as a result, polyethylene terephthalate is the main constituent component obtained by copolymerizing an aromatic dicarboxylic acid having a metal sulfonate group. It has been found that the problem can be solved by subjecting a conjugate fiber composed of polyester A and polyester B whose main repeating unit is ethylene terephthalate to a tension heat treatment at a specific temperature in a stretching step, and thus has achieved the present invention. That is, the present invention has the following configuration. (1) Polyester A in which the main constituent component obtained by copolymerizing 3 to 7 mol% of an aromatic dicarboxylic acid having a metal sulfonate group with respect to all the acid components is polyethylene terephthalate
And the main repeating unit is a composite fiber composed of polyester B of ethylene terephthalate, the fiber strength of which is 3.0 cN / dtex or less, the free shrinkage at 170 ° C. dry heat treatment is 15% or more, and 70% after the heat treatment. A latently-crimpable polyester conjugate fiber having a latent-crimping ability of exhibiting a spiral crimp of at least 25 mm. (2) The method for producing a latently crimpable polyester composite fiber according to the above (1), wherein a stretching heat treatment at a temperature of less than 120 ° C. is performed in the stretching step.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the present invention, as the polyester A, a polyester whose main constituent component obtained by copolymerizing an aromatic dicarboxylic acid having a metal sulfonate group is polyethylene terephthalate is used. Here, examples of the aromatic dicarboxylic acid having a metal sulfonate group include 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, and 4-sodium sulfoisophthalic acid. In the present invention, 5-sodium sulfoisophthalic acid (hereinafter referred to as SIP)
Abbreviated. ) Is preferably used.

In the polyester A, the copolymerization ratio of the aromatic dicarboxylic acid having a metal sulfonate group to all the acid components needs to be 3 to 7 mol%. When the copolymerization ratio is less than 3 mol%, the fiber strength increases, and the cutability of the nonwoven fabric becomes poor. In addition, crimp expression power becomes insufficient,
A nonwoven fabric with excellent elasticity cannot be obtained. Further, when the copolymerization ratio exceeds 7 mol%, the fiber strength is lowered, and there is an advantage that the cutability of the nonwoven fabric is improved. Absent.

On the other hand, as polyester B, a polyester whose main repeating unit is ethylene terephthalate is used. In addition, polyester A and polyester B
As long as the effect of the present invention is not impaired, it may contain a copolymer component other than the component that becomes an endocrine disrupting substance, a flame retardant, a fluorescent agent, a coloring agent, an antibacterial agent, a deodorant, A modifier or an additive such as an antistatic agent may be contained.

The fiber strength of the conjugate fiber is 3.0 cN / dte
x or less. Fiber strength is 3.0 cN / dt
When the value exceeds ex, the cutability of the nonwoven fabric is reduced, so that uniform cutting cannot be performed, and single yarn jumps out. Further, the blade holding time is shortened, which causes a problem in cost. If the fiber strength is low, there is an advantage that the cutability of the nonwoven fabric is improved, but since the problem of a decrease in operability in the spinning and drawing step and the card step occurs, the fiber strength is 2.0 to 3.0 cN / dt.
ex is preferably a fiber strength.

[0015] The free shrinkage of the composite fiber in the 170 ° C dry heat treatment must be 15% or more. Free shrinkage is 1
If it is less than 5%, in order to obtain a nonwoven fabric satisfying elasticity, it is necessary to perform a heat treatment temperature in the nonwoven fabric manufacturing process or to reduce the heat treatment speed, which is a problem in cost and productivity. Occurs.

Further, the conjugate fiber of the present invention needs to have a latent crimping ability to develop a spiral crimp of 70 pieces / 25 mm or more by free shrinkage heat treatment at 170 ° C. In order to obtain a nonwoven fabric having elasticity, when a crimp is developed, it is necessary that the fibers constituting the nonwoven fabric have a spiral crimp of 50 fibers / 25 mm or more, preferably 60 fibers / 25 mm or more. It is necessary to have a spiral crimp developing ability of 70 pieces / 25 mm or more in a raw cotton state.

In order to obtain the latently crimpable conjugate fiber of the present invention, it is necessary to perform a tension heat treatment at a temperature of less than 120 ° C. in the step of drawing the conjugate fiber. Heat treatment temperature is 1
When the temperature exceeds 20 ° C., in order to obtain a nonwoven fabric which can satisfy the elasticity, it is necessary to perform a heat treatment in the nonwoven fabric process at a higher temperature or to reduce the heat treatment speed, which causes problems in cost and productivity. Come up.

[0018]

According to the present invention, uniform cutting is possible in the step of cutting a non-woven fabric made of latently crimpable polyester composite fiber, and a non-woven fabric having excellent stretchability can be obtained.
The present invention provides a latently crimpable polyester conjugate fiber that is not concerned with endocrine disrupting properties that adversely affect the human body, for the following reasons. The conjugate fiber of the present invention uses, as the polyester B, a polyester whose main component is 3 to 7 mol% of an aromatic dicarboxylic acid having a metal sulfonate group with respect to all the acid components and whose main component is polyethylene terephthalate. Since the main repeating unit is a polyester of ethylene terephthalate, the fiber strength is low, and the latent crimpable polyester composite fiber having good crimp development property, the nonwoven fabric obtained from this composite fiber has improved cuttability. It has excellent elasticity and safety to the human body. In addition, since the conjugate fiber having the polymer structure is subjected to a tension heat treatment at a specific temperature in the drawing step, it is possible to stably obtain a latently crimpable polyester conjugate fiber having the above characteristics.

[0019]

Next, the present invention will be described specifically with reference to examples. The measuring method is as follows. (1) Intrinsic viscosity (η) Using an equal weight mixed solvent of phenol and ethane tetrachloride,
It was measured at a temperature of 20 ° C. (2) Single yarn fineness (dtex) Measured according to the method of JIS L-1015 7-5-1-1A. (3) Fiber strength (cN / dtex) Measured according to the method of JIS L-1015 7-7-1. (4) Heat shrinkage (%) Measured according to JIS L-1015 7-15. (5) Number of crimps (pieces / 25 mm) Measured according to the method of JIS L-1015 7-12-1. The latent crimp was made visible by heat-treating the short fibers at 170 ° C. for 15 minutes under conditions that allow free shrinkage. (6) Elongation The nonwoven fabric was cut into a width of 5 cm, the length L0 under a load of 30 g and the length L1 under a load of 240 g were measured, and the elongation was calculated from the following equation. Elongation rate (%) = [(L1-L0) / L0] × 100 (7) Nonwoven fabric cutting property The nonwoven fabric was cut using a guillotine cutter, and the rate at which a single yarn jumped out of the cut surface was used as an evaluation index. The smaller this value is, the better the cutability of the nonwoven fabric is.

Examples 1 and 2, Comparative Example 1 As the polyester A constituting the component of the conjugate fiber, 2 mol%, 3 mol% and 5 mol of SIP having an intrinsic viscosity of 0.80 were used, respectively.
Mol% copolymerized three types of polyethylene terephthalate copolymerized polyesters were used, and as polyester B, polyethylene terephthalate having an intrinsic viscosity of 0.68 was used.
A composite melt spinning apparatus uses a composite spinneret having a fiber cross-sectional shape of side-by-side type and having 1390 discharge holes, a composite ratio of 1/1, a spinning temperature of 282 ° C, and a take-up speed of 1
Spin at 170 m / min and discharge rate of 989 g / min.
A kind of undrawn yarn was obtained.

Each of the obtained undrawn yarns is weighed at 110 ktex.
And a drawing ratio of 2.38 and a drawing temperature of 75.
After stretching at 110 ° C., performing tension heat treatment at 110 ° C., and applying mechanical crimping with a stuffing box, the cut length is 51 m.
m to obtain short fibers having a fineness of 2.8 dtex. Next, using a roller card, the staple fiber was processed at a speed of 20 m /
After forming a web in minutes, performing a needle punching treatment, and then performing a heat treatment at 170 ° C. for 3 minutes using a hot air passage type heat treatment machine to prepare a nonwoven fabric. Table 1 shows the characteristic values of the raw cotton and the nonwoven fabric.

Comparative Examples 2 to 4 Composite fibers and nonwoven fabrics were obtained in the same manner as in Example 1 except that the copolymerization components of polyester A and the copolymerization ratio were changed as shown in Table 1. Table 1 also shows the characteristic values of the obtained raw cotton and nonwoven fabric.

[0023]

[Table 1]

As is clear from Table 1, in Examples 1 and 2, the amount of the SIP copolymer was satisfied, so that the fiber strength of the obtained composite fiber was low and the cutability of the nonwoven fabric was good.
In addition, a nonwoven fabric having excellent crimp expression and excellent stretchability was obtained.

On the other hand, in Comparative Example 1, since the amount of the copolymerized SIP was small, the fiber strength was high and the cutability of the nonwoven fabric was poor, and a single yarn jumped out on the cut surface. In addition, a nonwoven fabric with little crimping and poor elasticity was obtained. Next, in Comparative Example 2, as a result of using the copolyester of SIP / IPA, the fiber strength was high, the cutability of the nonwoven fabric was poor, and the single yarn jumped out on the cut surface. In Comparative Example 3, as a result of increasing the copolymerization amount of SIP and IPA, the fiber strength decreased,
Although the cutability of the nonwoven fabric was good, yarn breakage occurred frequently in the spinning process, and there was a problem in operability. Further, in Comparative Example 4, as a result of using the BAEO / IPA copolymerized polyester, although the stretchability of the nonwoven fabric was the best, the fiber strength was high and the cutability of the nonwoven fabric was poor. In addition, since it contains bisphenol A, which is an endocrine disrupting substance, it cannot be suitably used as a sanitary agent or patch material intended for use.

Examples 3-4, Comparative Example 5 Composite fibers and nonwoven fabrics were obtained in the same manner as in Example 1, except that the tension heat treatment temperature in the stretching step was changed as shown in Table 2. Table 2 also shows the characteristic values of the obtained raw cotton and nonwoven fabric.

[0027]

[Table 2]

As is clear from Table 2, Examples 3 and 4
Satisfies the heat treatment temperature in the stretching step,
The crimping property of the composite fiber was good, the stretchability of the nonwoven fabric was excellent, and the heat shrinkage was low, so that a uniform nonwoven fabric was obtained.

On the other hand, in Comparative Example 5, since the heat treatment temperature in the stretching was high, crimping of the conjugate fiber was small, and the nonwoven fabric was poor in elasticity.

[0030]

Industrial Applicability The composite fiber of the present invention is composed of a component that is not likely to cause endocrine disruption that adversely affects the human body, and has a low fiber strength and a good crimp development property. Since it is a fiber, the nonwoven fabric obtained from this composite fiber has improved cuttability, and has excellent elasticity and safety for the human body. Further, according to the production method of the present invention, it is possible to stably obtain the conjugate fiber having the above-described configuration.

Claims (2)

[Claims] 1. A polyester A whose main constituent component is polyethylene terephthalate obtained by copolymerizing 3 to 7 mol% of an aromatic dicarboxylic acid having a metal sulfonate group with respect to all acid components, and a polyester B whose main repeating unit is ethylene terephthalate A composite fiber consisting of
The fiber strength is 3.0 cN / dtex or less, the free shrinkage at 170 ° C. dry heat treatment is 15% or more, and the material has a potential crimping ability to develop a spiral crimp of 70 pieces / 25 mm or more after the heat treatment. Latent crimpable polyester composite fiber. 2. The method for producing a latently crimpable polyester composite fiber according to claim 1, wherein a tension heat treatment at less than 120 ° C. is performed in the drawing step.