JP2003041439A - Heat bonding conjugated fiber and nonwoven fabric using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide both a concentric core-sheath type heat bonding conjugated fiber having improved crimpability and high adaptability to a nonwoven fabric production process and a soft and bulky nonwoven fabric having a uniform formation. SOLUTION: This concentric core-sheath type heat bonding conjugated fiber comprises a core part which is a polyolefin and a core part that is a polyester having a higher melting point than that of the polyolefin by >=20 deg.C. The heat bonding conjugated fiber is crimped at 12-19 number of crimps (crimps/25 mm), 10-20 percentage of crimps (%) and 0.8-1.1 percentage of crimps/number of crimps. The web strength measured by the method described in the text is 0.3-1.2 [g/g] and the fineness of the heat bonding conjugated fiber is 1.1-6.6 dtex. The mass ratio of the core/sheath is preferably (70/30) to (30/70). The nonwoven fabric is obtained by using >=70 wt.% of the heat bonding conjugated fiber.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a heat-adhesive conjugate fiber and a nonwoven fabric using the same. More specifically, the present invention relates to a concentric core-sheath type heat-bondable composite fiber which gives a soft, bulky, and uniformly formed non-woven fabric and has high compatibility with the non-woven fabric manufacturing process, and a non-woven fabric using the same.

[0002]

2. Description of the Related Art Thermoadhesive conjugate fibers are widely used as binder fibers for non-woven fabrics and cushion materials. In particular, the heat-adhesive composite fiber using polyolefin as the sheath component and polyester as the core component gives a nonwoven fabric having a soft texture, and is therefore widely used mainly for sanitary materials such as the surface material of a disposable diaper. The core-sheath type heat-adhesive conjugate fiber gives a non-woven fabric having a good texture, but it cannot give sufficient crimps as compared with the eccentric core-sheath type adhesive conjugate fiber having a latent crimp-developing ability. Only the ones with low bulk can be obtained. Therefore, the heat-adhesive conjugate fiber is often used by mixing it with other fibers such as ordinary polyolefin-based short fibers, but a proposal for solving troubles in these non-woven fabric manufacturing processes, and recent non-woven fabric production card high speed Nothing is known about adaptation.

[0003]

The object of the present invention is to improve the crimping property of the conventional polyolefin-based concentric-core-sheath type thermoadhesive conjugate fiber, which is not suitable for the non-woven fabric manufacturing process. It is an object of the present invention to provide a heat-adhesive conjugate fiber and a nonwoven fabric thereof, which makes it possible to produce a nonwoven fabric which is high, soft and bulky and has a uniform texture.

[0004]

Means for Solving the Problems As a result of intensive studies by the present inventors in order to solve the above-mentioned problems, as a result of performing heat treatment on a tow at a specific temperature range before a draw crimping step of a heat-adhesive conjugate fiber, The inventors have found that it is possible to improve crimping properties of these core-sheath type heat-adhesive conjugate fibers, which are the conventional drawbacks, and to provide sufficient crimping, and arrived at the present invention.

The present invention has the following constitution in order to solve the above problems. (1) A core-sheath type thermoadhesive composite fiber having a sheath component of polyolefin and a core component of polyester having a melting point of 20 ° C. or more higher than the melting point of the polyolefin, and having a number of crimps (pieces / 25 mm). 12 to 19, crimp ratio (%) is 10
A heat-adhesive conjugate fiber, characterized in that a crimp having a crimp ratio / crimp number of 0.8 to 1.1 is provided. (2) The thermoadhesive conjugate fiber according to (1) above, wherein the web strength measured by the method described in the text is 0.3 to 1.2 [g / g]. (3) The fineness of the thermoadhesive conjugate fiber is 1.1 to 6.6d.
The thermoadhesive conjugate fiber according to (1) or (2) above, which is tex. (4) The heat-adhesive conjugate fiber according to any one of (1) to (3), wherein the core / sheath mass ratio is 70/30 to 30/70. (5) A non-woven fabric comprising the thermoadhesive conjugate fiber according to any one of (1) to (3) in an amount of 70% by weight or more. (6) A non-woven fabric obtained by laminating the non-woven fabric according to (5) above.

[0006]

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

Examples of the polyolefin as the sheath component used in the present invention include polyethylene, polypropylene, and copolymers containing these as a main component. Among them, high density polyethylene is preferably used.

Examples of the polyester as the core component include polyethylene terephthalate, polybutylene terephthalate and copolymers containing these as a main component.

The melting point of these polyesters is 20 ° C. or more higher than that of the sheath component. If the melting point difference between the core component and the sheath component is less than 20 ° C., not only the sheath component but also the core component is melted during thermal bonding, and the resulting nonwoven fabric has a hard texture. In addition, when the core component has at least one hollow portion, the hollow component is lost due to the melting of the core component, which hinders the bulkiness of the nonwoven fabric.

The thermoadhesive conjugate fiber of the present invention has a crimp number (pieces / 25 mm) of 12 to 19 and a crimp rate (%) of 10 to 2.
It is necessary that crimps satisfying 0 and a crimp ratio / crimp number of 0.8 to 1.1 are provided. If the number of crimps and the crimp ratio are smaller than this range, a large amount of scattered fibers and dropout fibers called fly are generated when passing the card in the nonwoven fabric manufacturing process. On the other hand, when it is larger than this range, the card winding of the fiber is increased and the texture of the non-woven fabric is deteriorated.

The morphology of the composite fiber must be a core-sheath type. If it is not a core-sheath type, it peels off during stretching and when passing through a card, resulting in poor texture.

Further, the cross-sectional shape of the composite fiber is required to be concentric so that the texture of the non-woven fabric is good. In the case of the eccentric type, latent crimps are expressed in the heat treatment step during the production of the nonwoven fabric, resulting in bulkiness, but at the same time, shrinkage of the web occurs during the heat treatment, resulting in large irregularities on the surface of the nonwoven fabric, resulting in poor texture.

The web tenacity of the heat-bondable conjugate fiber measured by the method described in the text should be 0.3 to 1.2 [g / g]. If the web strength is smaller than this range, many fly and drop fibers are generated when passing the card in the nonwoven fabric manufacturing process. On the other hand, when it is larger than this range, the card winding of the fiber is increased and the texture of the non-woven fabric is deteriorated. Especially preferred is web strength of 0.
It is 5 to 1.0 [g / g], and more preferably 0.6 to 0.9 [g / g].

The fineness of the heat-adhesive conjugate fiber is 1.1 to 6.6.
It is preferably dtex. If the fineness is less than this range, a soft non-woven fabric can be obtained, but fly tends to occur when the card passes. On the other hand, if it is larger than this range, a bulky nonwoven fabric can be obtained, but it is hard to be soft.

The core / sheath composite ratio of the heat-adhesive composite fiber is 70/30 to 30/70 in terms of mass ratio in view of spinnability, stretchability, fiber mechanical strength, thermal performance, and non-woven fabric physical properties. Is more suitable, and it is more preferable to set the mass ratio to 60/40 to 40/60. When the core component is increased, the heat-adhesive component is decreased, and the adhesive strength of the nonwoven fabric is lowered. On the contrary, when the sheath component is increased, a problem occurs in mechanical strength.

By using the thermoadhesive conjugate fiber of the present invention in an amount of 70% by weight or more, a soft, bulky and uniformly formed nonwoven fabric can be obtained, and further, the compatibility of the nonwoven fabric manufacturing process becomes high. Further, by using the non-woven fabrics laminated, the softness, bulkiness, non-woven fabric strength and the like can be adjusted.

In carrying out the method of the present invention, first, the above-mentioned polyolefin and polyester are used,
Melt spinning is performed by a conventional method to obtain a concentric core-sheath type composite undrawn fiber.

Then, after the unstretched fibers are drawn, a heat treatment is carried out using a heating medium or a heating device at about 30 to 100 ° C. before crimping. Examples of the heat treatment method include a heating roller and steam treatment.

Crimpers are applied to the heat-treated fibers with a crimper. At this time, crimps are adjusted with a nip pressure and a stuffing pressure. The tow temperature immediately before the crimper is 30 to 30.
It is preferably 70 ° C. At the same time, it is necessary to set the temperature of the crimper roller to 60 to 90 ° C. At this time, if the treatment temperature is too low, the treatment effect is not substantially exhibited and the crimp is low. If the treatment temperature is too high, the polyolefin of the sheath component is fused and the yarn breaks frequently, which is not preferable.

The crimped fiber is subjected to hot air heat treatment in a tensionless state and dried. The hot air-heated fibers are cooled and cut into heat-adhesive composite short fibers.

The thermoadhesive conjugate fiber thus obtained has a concentric cross section but is sufficiently crimped to give a nonwoven fabric which is soft and bulky and has a uniform texture. Highly compatible with non-woven fabric manufacturing processes.

When a non-woven fabric is produced using the heat-adhesive conjugate fiber obtained by the method of the present invention, a web is usually formed using only the heat-adhesive conjugate fiber, and the web is heated to a temperature higher than the melting point of the polyolefin as the sheath component. The sheath component of the heat-adhesive conjugate fiber is melted by a heated heat treatment device, and the fibers are spot-joined.

If necessary, the heat-adhesive conjugate fiber obtained by the method of the present invention is mixed with other fibers such as polyolefin-based heat-adhesive conjugate fiber, polyester-based staple fiber, natural fiber such as rayon and cotton. It is also possible to manufacture a nonwoven fabric, a cushioning material, etc. by heat-bonding as a web.

With the recent widespread use of non-woven fabrics, the thermoadhesive conjugate fibers are often used at a high mixing ratio of 70% or more, or 100%, which is effective for a laminated non-woven fabric having such a layer.

The heat-adhesive conjugate fiber may contain additives such as a flame retardant, an antistatic agent, a matting agent and an antibacterial agent in the core component and the sheath component as long as the characteristics are not impaired.

[0026]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, the measuring method of the characteristic value etc. under implementation are as follows. (A) Number of crimps and crimp ratio Measured by the method described in JIS L-1015.

(B) Web Strength The web strength referred to here is measured by the following procedure. : The heat-bondable composite fiber is defibrated with a single beater opener. : About 10 g of the defibrated heat-adhesive conjugate fiber is uniformly put into a miniature card of about 10-inch width (here, SC200 manufactured by Daiwa Kiko Co., Ltd.), and almost all of the heat-adhesive conjugate fiber is removed from the card. Take the web until it comes out and wind it up on a drum to make a web (one pass through the card). : Remove the created web from the drum without applying tension and cut it to 25 cm in the fiber axis direction (MD). : The web cut into 25 cm is folded in three in the width direction (CD) and set in the tensilon with a chuck length of 18 cm. : Tensile tensile strength (unit: g) is determined at a tensile speed of 100 mm / min. : The weight (g) of the broken web is measured, and the value obtained by dividing the breaking stress by the web weight is taken as the web strength. : The operation of ~ is repeated three times and the average value of the three times is taken as the web strength.

(C) Nonwoven Fabric Bulk (Initial Bulk, Compressed Bulk) Tens of samples obtained by cutting a nonwoven fabric into a size of 50 mm × 50 mm are stacked in the same direction, and a thickness (initial volume) when a load of 3 g / m ² is applied. ), And the thickness (compressed bulk) when a load of 35 g / m ² is applied is measured. All are basis weight 30g / m
Correct with ² . (D) Nonwoven fabric strength (vertical (MD) strength, horizontal (CD) strength) A sample obtained by cutting a nonwoven fabric into MD and CD in a size of 25 mm × 150 mm is subjected to tensile measurement with Tensilon (with a basis weight of 30 g / m ²⁾ . to correct).

(E) Evaluation of non-woven fabric step A non-woven fabric was prepared from 100% of the heat-adhesive conjugate fiber at a speed of 100 m / min and a basis weight of 25 g / m ² from a 90-inch wide card. Summarized in 1.

[0030]

[Table 1]

(F) Texture of non-woven fabric For a sample obtained by cutting a non-woven fabric into a size of 100 mm × 100 mm, five panelists evaluated the softness by touch, and judged according to the following four grades. ◎: Good, ○: Slightly good, △: Normal, ×: Poor

Examples 1 to 5, Comparative Example 1 Polyethylene having a melting point of 130 ° C. is used as a sheath component, and the melting point is 260.
The core-sheath composite unstretched fiber having a core / sheath mass ratio of 40/60 as a core component was melt-spun. At this time, the sheath component was introduced into the composite spinneret pack at 260 ° C. and the core component at 295 ° C., and the discharge amount was 1442 g / from the spinneret having 1800 spinning holes with a hole diameter of 0.5 mm.
After spinning for 5 minutes and cooling and solidification, it is collected at a speed of 1500 m / min, single fiber 5.3 dtex, total 9500 dte.
An unstretched fiber bundle of x was obtained. This unstretched fiber bundle is heated to 70
After drawing 2.6 times at ℃, it was taken out at a speed of 120 m / min, and after steam heat treatment, crimping was given with a heated push-in crimper, and the temperature was 100% without tension.
It was treated with hot air at ℃ for 5.4 minutes, cooled and cut to obtain a heat-adhesive composite short fiber having a fineness of 2.6 dtex and a length of 44 mm. The heat-adhesive composite short fibers 100% are passed through a card machine to make a non-woven web, and the temperature is set to 1 by a hot air circulation type heat treatment machine
It was heat-treated at 40 ° C. for 10 seconds to prepare a nonwoven fabric having a basis weight of 30 g / m ² .

Table 2 shows the results of the evaluation of the fiber properties, web strength, nonwoven fabric properties, nonwoven fabric process, and texture of the nonwoven fabrics of the heat-bondable composite staple fibers obtained in the above Examples and Comparative Examples. In Comparative Example 1, since the crimp is low and the web strength is low,
Frequent fly was generated when passing the card, and the non-woven fabric had a low bulk and had a bad texture.

[0034]

[Table 2]

[0035]

According to the present invention, in the polyolefin-based concentric core-sheath type heat-bondable composite fiber, sufficient crimping can be imparted, and the composite fiber has high compatibility with the nonwoven fabric manufacturing process and is soft. It is possible to provide a nonwoven fabric that is bulky and has a uniform texture.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4L041 AA08 AA15 AA20 AA25 BA02                       BA05 BA21 BA49 BA59 BD04                       BD11 CA06 CA36 DD01 DD05                       DD14                 4L047 AA14 AA21 AA27 AB02 AB07                       AB09 BA09 BB01 BB06 BB09                       CB01 CB02 CB10

Claims (6)

[Claims] 1. A concentric core-sheath type heat-bondable composite fiber, wherein the sheath component is a polyolefin and the core component is a polyester having a melting point of 20 ° C. or more higher than the melting point of the polyolefin, and the number of crimps (piece / 25 mm). ) Is 12 to 19, the crimp ratio (%) is 10 to 20, and the crimp ratio / crimp number is 0.8 to
A heat-adhesive conjugate fiber, which is provided with a crimp of 1.1. 2. The heat-bondable conjugate fiber according to claim 1, wherein the web strength measured by the method described in the text is 0.3 to 1.2 [g / g]. 3. The fineness of the thermoadhesive conjugate fiber is 1.1 to.
The thermoadhesive conjugate fiber according to claim 1 or 2, which has a 6.6 dtex. 4. A core / sheath mass ratio of 70/30 to 30/70.
The thermoadhesive conjugate fiber according to any one of claims 1 to 3, wherein 5. A non-woven fabric comprising 70% by weight or more of the thermoadhesive conjugate fiber according to any one of claims 1 to 3. 6. A non-woven fabric obtained by laminating the non-woven fabric according to claim 5.