JPH07258951A - Nonwoven fabric and its production - Google Patents

Abstract

PURPOSE:To obtain a high-strength and high-modulus spunbonded nonwoven fabric comprising sheath-core type polyester conjugate fibers, suitable as a base fabric for asphalt roofings or tufted carpets. CONSTITUTION:Firstly, sheath-core type polyester conjugate fibers 8-10 denier in single fiber fineness made up of, a polyethylene terephthalate >=0.15 in birefringence as core component and a polyester 200-230 deg.C in melting point consisting of a polyethylene terephthalate/polytetramethylene isophthalate block copolymer as sheath component in the sheath-core ratio of (5:5) to (9:1) is produced by direct spin-draw process at a nozzle shear rate of 1000-4000sec<-1> and a draw ratio of 4.0-6.0. Subsequently, the fibers are pulled by an air sucker after passing an electric opener, stacked on a net conveyer to form into a web, which is, in turn, subjected to hot-air treatment to effect fusing of the intersections of the conjugate fibers in the web, thus obtaining the objective nonwoven fabric good in balance between fiber strength and interfiber bond strength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-woven fabric and a method for producing the same, which is composed of a polyester-based composite filament having a core-sheath structure and a large fineness, and has a high modulus and high strength, and is particularly useful as a base for asphalt roofing and tufted carpet. The present invention provides a non-woven fabric which is suitable as a cloth and can be efficiently produced by the spunbond method.

[0002]

2. Description of the Related Art The spunbond method is known as a method for manufacturing a nonwoven fabric. FIG. 1 shows an example thereof, 1 is a spinning nozzle, 2 is a spinning cylinder, and a large number of polyester-based composite fibers having a core-sheath structure discharged from the spinning nozzle 1 (the core component is polyethylene terephthalate, the sheath component is A multifilament yarn 3 made of a low-melting polyester polymer) is cooled by passing through a spinning cylinder 2, passed through a spinning guide 4 and taken up by a take-up take-up roll 5, and then by three preheating rolls 6, 7, 8. After being preheated, it is drawn between the four lower drawing rolls 9, 10, 11, 12 and then opened by the electric opening device 13 and discharged from the air sucker 14 onto the lower net conveyor 15. Then, the web 16 is formed. Then, the web 16 is conveyed in the direction of the arrow P by the net conveyor 15, and a required number of the webs 16 are piled up so that their fiber directions intersect at right angles according to the purpose, and then treated with hot air to obtain the composite fiber. The sheath component is melted, and the intersections of the composite fibers are heat-sealed to form a nonwoven fabric.

Conventionally, in the case of producing polyethylene terephthalate fiber, in order to reduce yarn breakage in the drawing region and enable stable spinning, the shear rate (however, the shear rate is the nozzle discharge amount Q (Cm ³ / sec),
Since it is common knowledge to set the hole diameter of the spinning nozzle and the spinning take-off speed so that (when the nozzle hole diameter is d (cm), 32Q / πd ³ is defined), 6000 sec ^-1 or more. Even when the polyester-series conjugate fiber having a core-sheath structure is directly spun and drawn as described above, the shear rate is set to 6000 sec ^-1 or more, as in the case of spinning a single component of polyethylene terephthalate.

[0004]

However, when the composite fiber containing polyethylene terephthalate having a birefringence of 0.15 or more as the core component is directly produced by the spinning and drawing process as described above, the yarn unevenness increases and the draw ratio is increased. When the value is set to 4.0 times or more, which is necessary for the physical properties of yarn, there is a problem that yarn breakage occurs frequently.

The present invention comprises a polyester-based composite fiber containing polyethylene terephthalate having a birefringence of 0.15 or more as a core component, and has less unevenness in the thickness of the fiber and less breakage during drawing, which is efficient. It has a large void between fibers and can be combined with a high viscosity solution such as asphalt or urethane, or it has excellent mechanical properties and can be used as a tufted carpet base fabric. The present invention provides a non-woven fabric and a method for producing the same.

[0006]

A nonwoven fabric of the present invention is a span obtained by depositing a composite fiber having a core-sheath structure composed of a core component and a sheath component having a low melting point in a web form and melting the sheath component. It is a bonded non-woven fabric, and the above-mentioned composite fiber has a birefringence of 0.
15 or more polyethylene terephthalate as a core component,
A polyester having a melting point of 200 to 230 ° C. is used as a sheath component, a core-sheath ratio is 5/5 to 9/1, and a fineness is 8 to 18 denier.

The method for manufacturing a nonwoven fabric according to the present invention is
Polyethylene terephthalate as core component, melting point 200
Polyester of ~ 230 ° C is used as the sheath component, and the core-sheath ratio is 5
A composite fiber having a core-sheath structure of / 5 to 9/1 and a fineness of 8 to 18 denier is produced by a direct spin-drawing method, the obtained composite fiber is deposited in a web form, and the web is treated with hot air to obtain a web. In the method for producing a non-woven fabric in which the intersecting portions of the conjugate fibers therein are fused, the above-mentioned conjugate fibers are spun at a nozzle shear rate of 1000.
The stretching is performed under the condition of ˜4000 sec ⁻¹ and the stretching ratio is 4.0 to 4.0.
It is characterized in that it is performed at 6.0 times.

The core component of the above composite fiber has a birefringence of 0.1.
It is composed of 5 or more polyethylene terephthalates. If the birefringence is less than 0.15, a high melting point that cannot withstand the heat treatment for heat-sealing the intersections of the composite fibers and the asphalt impregnation during asphalt roofing production, and the asphalt roofing or toughness will not be obtained. The high modulus required as a base fabric for a ted carpet cannot be obtained.

The sheath component of the above composite fiber has a melting point of 200-2.
The polyester is composed of 30 ° C., and examples of the polyester include a block copolymer of polyethylene terephthalate / polytetramethylene isophthalate, a phosphorus-containing copolymerized polyester, or a copolymerized polyester containing at least two of them. Particularly preferred is a block copolymer of polyethylene terephthalate / polytetramethylene isophthalate. The above melting point is 200
If the temperature is lower than ℃, there is a risk that the non-woven fabric will be separated at the fused part of the composite fiber during the asphalt impregnation, and if it is higher than 230 ° C, the core component will be deteriorated by heat when the cross part of the composite fiber is heat fused. However, the strength of the nonwoven fabric is reduced.

The constituent ratio of the core component and the sheath component in the above composite fiber is 5/5 to 9/1, preferably 6/4 to 8 /.
When the above ratio is less than 5/5, the thickness of the core component is insufficient. On the other hand, when it exceeds 9/1, the adhesive strength is insufficient. I can't get it.

The fineness of the above composite fiber is 8 to 18 denier, preferably 10 to 16 denier. If it is less than 8 denier, the desired single yarn tenacity and non-woven fabric tenacity cannot be obtained, and it is formed in the non-woven fabric. The voids become narrow, making it difficult to impregnate asphalt or urethane. On the other hand, if it exceeds 18 denier, the contact distance between the single yarns becomes sparse and the strength of the nonwoven fabric decreases.

The nonwoven fabric of the present invention is produced by laminating a web made of the above-mentioned composite fiber so as to have a basis weight suitable for the purpose and melting the sheath component. The basis weight is 40 to 3
00 g / m ² and particularly preferably 80 to 200 g / m ² .
When the basis weight is less than 40 g / m ² , the strength is insufficient, and when it exceeds 300 g / m ² , on the contrary, it becomes heavy and the workability is deteriorated, which is not preferable. In addition, the arrangement of the composite fibers is preferably a random arrangement having a small directivity and an orthogonal arrangement.

[0013] To produce the nonwoven fabric directly but spun stretching method or spinning simultaneous stretching method spunbond method utilizing is employed, in order to obtain the above-mentioned non-woven fabric 1000 to 4000 seconds nozzle shear rate ^{- Should} be set to ¹ ,
Particularly, 1000 to 2500 sec ^-1 is preferable. That is, it is set lower than the conventional common sense of 6000 sec- ¹ . If the shear rate is less than 1000 sec ^-1 , yarn breakage may occur in the spinning process or the drawing process, and the fineness irregularity of the obtained conjugate fiber may increase. 40 on the contrary
If it exceeds 00 sec ^-1 , hole bending discharge occurs directly under the nozzle, the draft ratio defined by the ratio of the nozzle diameter to the yarn diameter becomes insufficient, and the birefringence becomes less than 0.15. However, the object of the present invention is not achieved.

Further, in the method for producing a non-woven fabric according to the present invention, the stretching ratio in the stretching step subsequent to the spinning step is 4.0.
˜6.0 times, preferably 4.5 to 5.5 times. When this draw ratio is less than 4.0 times, the desired fiber strength cannot be obtained, and when it exceeds 6.0 times, the fiber speed at the end of the drawing step exceeds 1500 m / min. Orthogonal alignment becomes difficult when depositing composite fibers to form webs.

[0015]

The nonwoven fabric of the present invention comprises polyethylene terephthalate having a birefringence of 0.15 or more as a core component and a melting point of 200.
Since it is composed of a composite fiber having a core-sheath structure having a polyester of ˜230 ° C. as a sheath component, it is possible to heat the web made of the composite fiber to 200 to 230 ° C. to heat-bond the crossing part of the composite fiber. It is possible to heat the asphalt (temperature of 190 to 2
Even when it is impregnated with (10 ° C) or urethane, the core component is not damaged and the strength is preserved. In addition, since the core-sheath ratio of the above-mentioned composite fiber is 5/5 to 9/1 and the fineness is 8 to 18 denier, the balance between the fiber strength and the bonding strength between the composite fibers is good, and the strength as a nonwoven fabric is high. It has a high modulus, has appropriate voids between the conjugate fibers, and is easy to impregnate asphalt.

According to the method for producing a nonwoven fabric according to the present invention,
The birefringence is 0.15 or more, preferably 0.15 to 0.1
9, particularly preferably 0.15 to 0.18 polyethylene terephthalate as a core component, polyester having a melting point of 200 to 230 ° C. as a sheath component, and a core-sheath ratio of 5/5 to 9 /
1. A non-woven fabric composed of composite fibers having a fineness of 8 to 18 denier is obtained. Then, the composite fiber has a nozzle shear rate of 10
Since the fiber is spun under the condition of ^{0 to} 4000 sec ^-1 , it is a composite fiber, but the yarn breakage during drawing is small and the fineness unevenness is small, and the productivity is improved. Further, since the nozzle shear rate is set to 1000 to 4000 sec ^-1 and the draw ratio is set to 4.0 to 6.0 times as described above,
Sufficient fiber strength can be obtained, and the final take-up speed of the composite fiber after drawing can be suppressed to 1500 m / min or less, which facilitates orthogonal arrangement when deposited as a web.

[0017]

EXAMPLE A polyethylene terephthalate (intrinsic viscosity 0.64) was used as a core component, a block copolymer of polyethylene terephthalate, isophthalic acid and butanediol was used as a sheath component, and a composite fiber having a core-sheath ratio of 8/2 was used. Was produced. That is, the above polymer is melted at 277 ° C., discharged from the multi-hole nozzle 1 shown in FIG. 1, cooled and solidified in the spinning cylinder 2, and the obtained composite fiber yarn 3 is taken up by the spinning take-up roll 5 and preheated. Roll 6,
Preheat at 7, 8 and then draw rolls 9, 10, 11, 1
2 times to 5 times, and opened by the electric opening device 14,
It was pulled by the air sucker 14 and accumulated on the net conveyor 15.

However, the number of holes in the nozzle was 511, the discharge speed was 1.33 g / min. / Hole, the take-up speed of the spinning take-up roll 5 was 200 m / min, and preheating by the preheating rolls 6, 7 and 8 The temperature is set to 85 ° C., the draw ratio by the draw roll 9 is unified to 5 times, and the nozzle hole diameter, the nozzle shear rate, and the nozzle draft (ratio between the peripheral speed of the take-up roll 5 and the discharge linear speed) are shown in the following table. A total of five types of webs of Examples 1 to 3 and Comparative Examples 1 and 2 were manufactured by changing as shown in FIG.

Table 1 Nozzle diameter Nozzle shear rate Nozzle draft Example 1 0.40 (mm) 2991 (sec ^-1 ) 22.3 (times) Example 2 0.45 2101 28.2 Example 3 0.50 1532 34.8 Comparative Example 1 0.35 4465 17.1 Comparative Example 2 0.60 886 50.1

In producing the webs of Examples 1 to 3 and Comparative Examples 1 and 2, the number of yarn breakages (per nozzle) during drawing was compared. Further, the composite fiber was taken out from the obtained web, the single yarn fineness and the single yarn tenacity thereof were measured, and further, the birefringence (Δn) of the core component was measured. The results are shown in Table 2 below. However, the birefringence was measured by pulling out a single yarn from the non-woven fabric and using a compensator method with a 10 × 20-fold polarizing microscope. In addition, the single yarn tenacity is a tensile tester ("Tensilon UTM-II" manufactured by Orientec Co., Ltd.
I L ”), distance between chucks 20mm, pulling speed 2
It was measured at 0 mm / min. However, the number of samples is 10.

Table 2 Thread break Single thread fineness Single thread tenacity Birefringence Example 1 1.5 (cases / day) 12 (d) 5.2 (g / d) 0.162 Example 2 0.5 12 5.3 0.157 Example 3 0.15 12 5.7 0.153 Comparative Example 1 12 12 4.7 0.143 Comparative Example 2 14 12 3.9 0.137

As is clear from Tables 1 and 2 above, in Examples 1, 2, and 3 of the present invention, yarn breakage was small,
Single yarn strength is excellent. In particular, Example 2 and Example 3
Since the nozzle shear rate was adjusted to 2100 to 1500 sec ^-1 and the nozzle draft was adjusted to 28 to 40, the yarn breakage was very small and the yarn quality was good. On the other hand, in Comparative Example 1, since the nozzle shear rate is excessively high, the birefringence is 0.143, and in Comparative Example 2, since the nozzle shear rate is excessively low, the birefringence is 0.137. There were many yarn breakages and the single yarn strength was also low.

When depositing the webs of Examples 1 to 3 and Comparative Examples 1 and 2 on the net conveyor 15, the air sucker 14 is swung back and forth and left and right so that the fiber directions are substantially orthogonal to each other, and the basis weight is Piled up to 120 g / m ² ,
This is treated with hot air at a temperature of 240 ° C. to soften the sheath component, and then pressed with a roller to bond the intersections of the composite fibers to form a nonwoven fabric, which has a dry strength (DT) and a stress at 5% elongation (ST). Was measured. The results are shown in Table 3 below. However, the above-mentioned dry strength (DT) and stress at 5% elongation (ST) were measured by using a tensile tester ("Tensilon UCT-500" manufactured by Orientec Co., Ltd.), a distance between chucks of 10 cm, a gripping margin of 5 cm, Pulling speed 200mm /
Measured in minutes. In the table, (T) shows the measured value in the vertical direction, and (W) shows the measured value in the horizontal direction.

Table 3 DT (T) DT (W) ST (T) ST (W) (kgf / 5cm) (kgf / 5cm) (kgf / 5cm) (kgf / 5cm) Example 1 61 34 34 24 Example 2 63 37 35 25 Example 3 65 38 35 25 Comparative Example 1 50 30 28 20 Comparative Example 2 45 26 24 17

As is clear from Table 3 above, Examples 1 to 3 of the present invention all had high modulus and high strength. On the other hand, Comparative Examples 1 and 2 were both low-strength nonwoven fabrics.

[0026]

The invention described in claim 1 uses polyethylene terephthalate having a birefringence of 0.15 or more as a core component, a thermoplastic polymer having a melting point of 200 to 230 ° C. as a sheath component, and a core-sheath ratio of 5/5. Since it is a non-woven fabric composed of composite fibers having a core-sheath structure of 9 to 9/1 and a fineness of 8 to 18 denier, it has a good balance of fiber strength and adhesive strength between composite fibers, and has high strength and modulus as a non-woven fabric. Moreover, it has excellent heat resistance, has suitable voids in the non-woven fabric, is easy to impregnate asphalt, and is particularly suitable as a base fabric for asphalt roofing and tufted carpet. Is.

In the invention described in claim 2, polyethylene terephthalate is used as a core component, and the melting point is from 200 to 23.
Using 0 ° C polyester as the sheath component, the core-sheath ratio is 5/5
A composite fiber having a 9/1 core-sheath structure and a fineness of 8 to 18 denier was produced by a direct spin-drawing method, the obtained composite fiber was deposited in a web shape, and the web was treated with hot air to form a composite material in the web. In the method for manufacturing a non-woven fabric in which the intersecting portions of fibers are fused, the spinning of the above composite fibers is carried out at a nozzle shear rate of 1000 to 4
The stretching is performed under the condition of 000 sec ^-1 and the stretching ratio is 4.0 to 6.
Since the method is carried out at 0 times, the nonwoven fabric according to claim 1 can be produced, and even though it is a composite fiber, there are few yarn breakages at the time of stretching, and the unevenness of fineness is reduced, and the productivity is improved. And the final take-up speed of the composite fiber after drawing can be suppressed to 1500 m / min or less,
Therefore, when deposited as a web, orthogonal arrangement becomes easy.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment.

[Explanation of symbols]

 1: Nozzle 2: Spinneret 3: Multifilament yarn consisting of composite fibers 4: Spinning guide 5: Spinning take-off roll 6, 7, 8: Preheating roll 9, 10, 11, 12: Drawing roll 13: Electric opening Equipment 14: Air Soccer 15: Net Conveyor 16: Web

Claims (2)

[Claims] 1. A spunbonded non-woven fabric obtained by depositing a composite fiber having a core-sheath structure composed of a core component and a sheath component having a low melting point in a web form and melting the sheath component, wherein the composite fiber is Polyethylene terephthalate having a birefringence of 0.15 or more is used as a core component, polyester having a melting point of 200 to 230 ° C. is used as a sheath component, the core-sheath ratio is 5/5 to 9/1, and the fineness is 8 to 1
A non-woven fabric characterized by being 8 denier. 2. A composite fiber having a core-sheath structure of polyethylene terephthalate as a core component, polyester having a melting point of 200 to 230 ° C. as a sheath component, and a core-sheath ratio of 5/5 to 9/1 and a fineness of 8 to 18 denier. Produced by a direct spinning drawing method, the resulting composite fibers are deposited in a web shape, and the web is treated with hot air to fabricate a non-woven fabric in which the intersections of the composite fibers in the web are fused, A method for producing a non-woven fabric, which comprises spinning at a nozzle shear rate of 1000 to 4000 sec ^-1 , and stretching at a draw ratio of 4.0 to 6.0.