JP2003227061A - Spunbonded nonwoven fabric composed of multifilament yarn and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spunbonded nonwoven fabric which can be produced without disturbing operation and can satisfy required performances over wide variety of applications. <P>SOLUTION: The spunbonded nonwoven fabric composed of multifilament yarns is composed of a thermoplastic polymer and keeps the shape by thermally bonding multifilaments to each other. The multifilament yarn has preferably twist or single fibers constituting the multifilament yarn are preferably fused to each other by melting or softening a part of the surface of the thermoplastic polymer constituting the single fibers. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a spunbonded nonwoven fabric.

[0002]

2. Description of the Related Art Conventionally, a nonwoven fabric obtained by a spun bond method, that is, a thermoplastic polymer is melted, and a spun yarn group is taken by a high-speed air stream, drawn, opened, and captured on a net conveyor. Collect and deposit to form a non-woven web,
It is well known that a non-woven fabric composed of long fibers in which fibers are integrated by thermal bonding or the like has higher productivity than dry non-woven fabric or wet non-woven fabric and has excellent mechanical properties such as tensile strength. .

The spunbonded nonwoven fabric is preferably used in various fields such as industrial and industrial materials such as construction, civil engineering and vehicles, medical materials, sanitary materials, daily life materials, agriculture, gardening and forestry materials. In addition, they are used for various applications in these fields, and as the applications are expanded, the required performances required for spunbonded nonwoven fabrics are also diversified.

For example, in the fields of agriculture, horticulture and forestry materials, when a plant such as a young tree or a farm product is grown, it can be protected from various external enemies and can be well grown.
It is surrounded by non-woven fabric or covered. At this time, the non-woven fabric is required to have appropriate strength in order to protect it from external enemies and in terms of handleability, and is also required to have sufficient air permeability and translucency for good growth.

In a spunbonded nonwoven fabric, in order to improve air permeability and translucency, the amount of fiber per unit area (length) is reduced by reducing the weight per square meter (hereinafter referred to as a unit weight). It is possible to increase the opening area (area of the portion where the fiber does not exist) by decreasing. However, since a nonwoven fabric having a reduced amount of fibers per unit area is significantly inferior in the nonwoven fabric strength, it is difficult to satisfy both the strength and the air permeability / translucency of the nonwoven fabric.

Further, as a method of satisfying both of the above required performances, it is considered that the single yarn fineness of the single fibers constituting the non-woven fabric is extremely increased. However, when attempting to melt-spin a single yarn having a very high fineness by the spunbond method, an extremely long distance cooling zone is required to cool the melt-spun spun yarn because the fineness is extremely high. Further, an air sucker having an extremely high suction capability is required, a device for controlling these becomes complicated, and a facility that enables this is not realistic.
Therefore, from the point of view of production equipment, there is a limit to increasing the single yarn fineness, and as the fineness is increased, the spinnability and openability are deteriorated. Obtaining more than 15 decitex is considered to be difficult in operation.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a spunbonded non-woven fabric which can solve the above-mentioned problems, can be produced without hindering the operation, and can satisfy a wide variety of performance requirements. To do.

[0008]

Means for Solving the Problems The present inventor has made earnest studies in view of such a situation. In the manufacturing process of spunbonded non-woven fabric, it is common knowledge that the melt-spun yarn is introduced into air sucker, towed and stretched at high speed, and then individual filaments are spread apart by a spreader and deposited. However, by breaking the common sense and intentionally forming multifilament yarn without breaking individual single fibers with an opener, a new spunbond that can satisfy various required performances. The inventors have found that a non-woven fabric can be obtained and have reached the present invention.

That is, the present invention is a spunbonded non-woven fabric composed of multifilament yarns made of a thermoplastic polymer, wherein the multifilament yarns are heat-bonded to each other to maintain their shape. The gist is a spunbonded non-woven fabric made of multifilament yarns.

Further, according to the present invention, a thermoplastic polymer is melt-spun, a spun yarn is introduced into air sucker, towed and drawn, and a multifilament yarn in a state in which single fibers are bundled is obtained from the air sucker. A spunbond consisting of multifilament yarns, characterized in that the multifilament yarns are discharged and deposited on the movable collecting surface to form a web of multifilament yarns, and then the multifilament yarns are thermally bonded together by heat treatment. The gist of the invention is a method of manufacturing a non-woven fabric.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The spunbonded nonwoven fabric of the present invention is
It is composed of multifilament yarn made of a thermoplastic polymer.

The multifilament yarn according to the present invention is
The plurality of single fibers constituting the multifilament yarn are converged so as not to be easily separated, but the multifilament yarn may be converged by having a twist, and the multifilament yarn is constituted. The single fibers may be converged by being fused by melting or softening a part of the surface of the thermoplastic polymer forming the single fibers. Moreover,
In the twisted state of the multifilament yarn, the single fibers may be fused by melting or softening a part of the surface of the thermoplastic polymer constituting the single fibers. .

When the multifilament yarn has a twist, the number of twists is 1 T / 10 cm or more, preferably 5
It may be T / 10 cm or more. Number of twists is 1T / 10c
When it is less than m, a plurality of single fibers are not converged but are scattered and easily dispersed, which is not the object of the present invention. The upper limit of the number of twists is not particularly limited.

In the case where the multifilament yarn is obtained by fusing the monofilaments with each other, the degree of the fusion is such that they do not easily come apart, and the individual monofilaments have a fiber form. Even if it ’s well maintained,
Further, not only a part of the surface of the thermoplastic polymer constituting the single fiber, but also melted or softened to the inside, so that the boundary surface between the single fibers is not so clear that it is firmly fused. You may

The multifilament yarn according to the present invention is
It is composed of a thermoplastic polymer. As the thermoplastic polymer, it is sufficient to use a thermoplastic polymer that has been conventionally used for spunbond nonwoven fabrics, polyester-based polymer, biodegradable polyester-based polymer, polyamide-based polymer,
A polyolefin-based polymer may be used. Further, it may be a copolymer, for example, when using a polyester-based copolymer, alkylene terephthalate as a main component, acid components such as isophthalic acid and adipic acid, tetramethylene glycol, neopentyl glycol and the like. The thing which copolymerized the diol component is mentioned.

In addition, various additives such as matting agents, pigments, flame retardants, light stabilizers, heat stabilizers, antioxidants, flame retardants, etc. may be added to these polymers depending on the use and the like. You may add.

The form of the single fiber constituting the multifilament yarn may be a single-phase form composed of one kind of polymer or a composite form composed of two or more kinds of polymers.

In the present invention, when the monofilaments are fused with each other as the multifilament yarn, or because the multifilament yarns are heat-bonded to each other to maintain the nonwoven fabric form, the form of the monofilament is It is preferable that the core-sheath composite type is one in which a high melting point polymer is arranged in the core component and a low melting point polymer is arranged in the sheath component. When the form of the single fiber is the core-sheath composite type, the multifilament yarn in which the single fibers are fused to each other can be efficiently produced by the production method described later. Further, in the core component, since the molecules are sufficiently oriented, the strength of the fiber is high, while the sheath component functions as a binder for fusing the single fibers together, and the multifilament yarns It is preferable because it can function as a binder for adhering.

The cross-sectional shape of the single fiber is not particularly limited and can be appropriately selected from a general circular cross section, a flat cross section, a polygonal cross section, a hollow cross section having a hollow portion, and the like.

The total fineness of the multifilament yarn constituting the spunbonded nonwoven fabric of the present invention is not particularly limited and may be appropriately selected according to the required performance such as application. It is preferable that the spunbonded nonwoven fabric made of the multifilament yarn of the present invention has 15 decitex or more in order to exert a superior effect as compared with the conventional spunbonded nonwoven fabric in which monofilaments are separately deposited. Further, it is preferably 30 decitex or more. By setting the total fineness of the multifilament yarn to 15 decitex or more, excellent properties such as rigidity, tear strength, air permeability, and translucency can be obtained. The upper limit of the total fineness of the multifilament yarn is not particularly limited, and may be appropriately selected depending on the application and the like.

The monofilament fineness of the monofilaments constituting the multifilament yarn and the number of monofilaments constituting the multifilament yarn may be appropriately selected according to the total fineness of the multifilament yarn and the use of the spunbonded nonwoven fabric. It is not particularly limited. Regarding the single yarn fineness of the single fiber, 5 to 1
Use about 5 decitex. When it is attempted to obtain a multifilament yarn by fusing single fibers together, it is difficult for the single fibers to converge and to be fused because the fibers are easily cooled in the spinning step when the number is less than 5 decitex. Become. On the other hand, if it exceeds 15 decitex, the fibers are difficult to cool, so that the fusion of the single fibers becomes excessive, and it is not realistic to obtain the intended multifilament yarn, because it is difficult to produce it with ordinary equipment.

The spunbonded nonwoven fabric made of the multifilament yarn of the present invention retains its shape by being heat-bonded. Here, the term “heat-bonding” means that the thermoplastic polymer constituting the single fiber is bonded by being melted or softened by heat. Specifically, even if it is heat-bonded by having a partial thermocompression bonding portion formed by hot embossing, it is also heat-bonded by heat treatment by thermal calendering, heat by hot air treatment. It may be glued. Also, a combination of these methods may be used. In the present invention, from the viewpoint of the morphological stability of the spunbonded nonwoven fabric, it is preferable that the spunbonded nonwoven fabric is heat-bonded by applying heat and pressure, that is, heat-embossing or heat-calendering.

The basis weight of the spunbonded nonwoven fabric comprising the multifilament yarn of the present invention is preferably 15 g / m ² or more. When the basis weight is less than 15 g / m ² , the shape retention tends to be poor, and the handleability tends to be difficult. The upper limit is not particularly limited and may be appropriately selected depending on the application, cost and the like.

The spunbonded nonwoven fabric made of the multifilament yarn of the present invention can be used alone or in combination with other materials. That is, it may be used as a spunbonded non-woven fabric obtained by laminating other ordinary single fibers in a discrete manner, a short-fiber non-woven fabric, a melt-blown non-woven fabric, paper, a woven / knitted fabric, a film, or the like as a composite material.

Next, a preferred method for producing a spunbonded nonwoven fabric made of the multifilament yarn of the present invention will be described.

First, a thermoplastic polymer is melt-spun using a spinneret, spun yarn (a plurality of single fiber groups) is introduced into an air sucker, and drawn and stretched to a desired fineness,
The multifilament yarn in a state in which a plurality of single fibers are bundled is discharged from the air sucker.

In order to discharge the multifilament yarn in a state in which a plurality of spun single fibers are converged from the air sucker, it is preferable to twist it in the air sucker. As a method of applying twist in the air sucker, it is preferable to make the flow of the pulling air in the air sucker a spiral flow. Specifically, there is a method of making a swirl flow by attaching a blade to the entrance or the inside of the air sucker and moving the blade, and a method of blowing air to the entrance or the inside of the air sucker to make a swirl flow. Can be mentioned.

Further, it is preferable to fuse a plurality of single fibers to each other before or into the air sucker to obtain a multifilament yarn. Specifically, in the spun yarn that is melt-spun from the spinneret, when individual single fibers are not completely cooled (single fibers can be fused), a plurality of A method may be mentioned in which single fibers are adhered to each other to be fused and then introduced into an air sucker. In addition, the air sucker inlet is designed to be small so that the individual single fibers are not completely cooled (the single fibers can be fused together) and introduced into the air sucker. In addition, there is a method in which single fibers are in close contact with each other and are fused together. In order to discharge the multi-filament yarn formed by fusing single fibers from the air sucker,
When the single fibers are brought into close contact with each other, it is necessary that the fibers can be fused. Therefore, the distance to the position (guide position or air sucker inlet) to be brought into close contact with the mouthpiece, the pulling speed, etc. should be determined by the heat used. It is appropriately set depending on the plastic polymer, the amount of single-hole protrusion, and the like. Also, when fusing the single fibers together,
Depending on the state of the thermoplastic polymer that constitutes the single fiber, the fusion state of the single fibers (fusion that does not easily come apart, strong fusion, etc.) can be determined.

Next, the multifilament yarn discharged from the air sucker is deposited on the movable collecting surface to form a web made of the multifilament yarn. When depositing the multifilament yarn on the movable collecting surface, it is preferable that the multifilament yarn is shaken in the width direction to be deposited by blowing air or the like onto the multifilament yarn immediately after being discharged from the air sucker. As air is blown alternately from the left and right, the multifilament yarn can be deposited in a loop shape on the movable collecting surface in a gentle spiral, so it is deposited in a random loop shape. It is possible and preferable.

Then, the obtained web of multifilament yarns is heat-treated to thermally bond the multifilament yarns together to obtain a spunbonded nonwoven fabric of multifilament yarns.

As the heat treatment, hot embossing using an embossing device consisting of a pair of embossing rolls or an embossing device consisting of an embossing roll and a flat roll, thermal calendering using a calendering device consisting of a pair of flat rolls, hot air dryer, etc. A hot air treatment in which heat treatment is performed through the resin is included, and it is preferable to perform hot embossing or thermal calendering from the viewpoint of morphological stability.

Regarding the hot embossing, the size of the partial thermocompression bonding portion of the obtained spunbonded nonwoven fabric, the disposition density of the partial thermocompression bonding area, and the pressure contact area depend on the area of the convex portion of the embossing roll and the disposition density. The rate is determined. The area of the convex portion of the embossing roll and the pressure contact area ratio (ratio of the area of the total convex portion to the total surface area of the roll) are not particularly limited as long as the shape of the obtained spunbond nonwoven fabric can be retained, but the area of the convex portion is not limited. Is about 0.1 to ⁵ mm ² and the pressure contact area ratio is about 10 to 60% (the ratio of the area of all the convex portions to the total surface area of the roll), and may be appropriately selected depending on the application and required performance. In the spunbonded nonwoven fabric of the present invention, particularly when the total fineness is made of multifilament yarn having a large fineness of 100 decitex or more,
For example, in the case of a low basis weight of about 30 g / m ² or less, the number of multifilament yarns occupying a unit area is small, and thus a large number of large voids (openings) when viewed two-dimensionally (area). There is a part. Therefore, in consideration of shape retention, it is preferable that the area of the convex portion is large and the press contact area ratio is large. It is also preferable to perform heat treatment with a calendar device.

[0033]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples. In addition, each characteristic value in the examples was obtained as follows. (1) Intrinsic viscosity [η] of polyester: 0.5 g of a sample was dissolved and measured in 100 cc of a mixed solvent of phenol and ethane tetrachloride in an equal mass ratio.

(2) Melting point (° C.); using a differential scanning calorimeter DSC-7 type manufactured by Perkin Elmer Co., Ltd., a heating rate of 20
It was measured at ° C / min.

(3) Tensile strength of non-woven fabric (N / 5 cm
Width); Synthetic long fiber non-woven fabric test method (JISL 1906)
According to, Toyo Baldwin Co., Ltd. Tensilon RTM-
Using a 500 type, a test piece having a width of 50 mm and a length of 200 mm was measured under the conditions of a gripping interval of 100 mm and a pulling speed of 100 mm / min, and an average value of 10 points of the sample was determined to obtain tensile strength. The tensile strength was determined both in the MD direction (machine direction) and the CD direction (direction orthogonal to the MD direction) of the nonwoven fabric.

(4) Tear strength (N) of nonwoven fabric; JIS
Tear strength of L 1906 The tear strength of the nonwoven fabric in the MD direction was measured by the pendulum method.

(5) Light transmittance (%); JIS L 190
6 According to the translucency, the illuminance was measured as 500 lx.

Example 1 A chip made of polyethylene terephthalate (melting point 260 ° C., intrinsic viscosity 0.70) was used as a raw material, and a known melt-spinning apparatus was used. Melt spinning was performed at a spinning temperature of 280 ° C. The distance between the spinneret and air soccer is set to 60 cm,
The spun yarn was introduced into an air sucker having a small air sucker inlet (diameter: 5 mm). At this time, 30 single fibers were introduced into one air soccer. Then, in air soccer, the fineness of the single fiber is 5.
A multifilament with a total fineness of 150 decitex was obtained by pulling at a pulling speed of 4000 m / min so as to be 0 decitex, and at the same time, the single fibers were adhered and fused in an air sucker, and 30 monofilaments were converged by the fusion. The thread was discharged from the air soccer.

The multifilament yarn discharged from the air sucker is swung by the air blower from the left and right,
While being spirally rotated, it was collected and accumulated on a conveyor net to obtain a web made of multifilament yarn.

This web was introduced into a hot embossing device consisting of an embossing roll (embossing convex area: 0.9 mm ² , area ratio: 21%) and a flat roll, and both rolls had a surface temperature of 230 ° C. and a linear pressure of 294 N / cm. Partial heat-pressing treatment was performed under the conditions described above to obtain a spunbonded nonwoven fabric composed of multifilament yarn having a basis weight of 50 g / m ² .

Example ² A spunbonded nonwoven fabric having a basis weight of 100 g / m ² was produced in the same manner as in Example 1.

Example 3 A chip made of polyethylene terephthalate (melting point 260 ° C., intrinsic viscosity 0.70) and polyethylene (melting point 12
A known core-sheath composite melt spinning is prepared by using as a raw material a chip having a melt flow rate of 5 ° C. (measured by a method described in JIS K 6922 at a temperature of 190 ° C. and a load of 21.18 N) of 25 g / 10 minutes). Using a device, polyethylene terephthalate is placed in the core part and polyethylene is placed in the sheath part from a composite spinneret with 42 holes, where the fiber cross section is core-sheath type, and the mass ratio (1/1) so,
Melt spinning was performed at a spinning temperature of 280 ° C. The distance between the spinneret and air sucker is set to 60 cm, and the spun yarn has a small air sucker inlet (diameter: 5 m).
m) Introduced to air soccer. At this time, 14 single fibers were introduced into one air soccer. Then, in the air sucker, the single fibers were pulled at a pulling speed of 4000 m / min so that the fineness of the single fibers was 10 decitex, and at the same time, the single fibers were closely adhered and fused in the air sucker, and the 14 single fibers were fused. Total fineness converged by wearing is 14
A 0 decitex multifilament yarn was discharged from the air sucker.

The multifilament yarn discharged from the air sucker is swung by the air blower from the left and right,
While being spirally rotated, it was collected and accumulated on a conveyor net to obtain a web made of multifilament yarn.

This web was introduced into a hot embossing device consisting of an embossing roll (the area of the embossed convex portion was 0.9 mm ² and the area ratio was 21%) and the surface temperature of both rolls was 120 ° C. and the linear pressure was 500 N / cm. Partial heat-pressing treatment was performed under the conditions described above to obtain a spunbonded nonwoven fabric composed of multifilament yarns having a basis weight of 100 g / m ² .

Example 4 In Example 1, the distance between the spinneret and the air sucker was 120 cm, and as the air sucker, the inlet of the air sucker was not small, and the stationary blade was attached to the inlet. Example 1 except that one was used
A spunbonded nonwoven fabric composed of multifilament yarn was obtained in the same manner as in.

By attaching a stationary blade to the inlet of the air sucker, the flow of the pulling air is made into a swirl flow in the air sucker, and the multifilament yarn constituting the obtained spunbonded nonwoven fabric has a twist. The fibers are converged, and the single fibers are not fused with each other.

Comparative Example 1 In Example 1, the distance between the spinneret and the suction device was 120.
cm, the single inlet of the air sucker is not made small, and the single fibers are not adhered to each other in the air sucker. After discharging from the air sucker, the single fibers are opened by the opener. A long-fiber non-woven fabric was produced in the same manner as in Example 1 except that the moving collection surface was collected and deposited, and the web had a basis weight of 15 g / m ² .

Table 1 shows the evaluation of physical properties of the obtained nonwoven fabrics of Examples 1 to 4 and Comparative Example 1.

[0049]

[Table 1]

As is clear from Table 1, Examples 1 to 4
The spunbond nonwoven fabric made of multifilament yarns, yet those high and ^{50g / m 2, 100g / m} 2 basis weight, which gap (opening) moiety is present, the low basis weight, such as in Comparative Example 1 It had a light-transmitting property as good as the above. Further, it was excellent in tear strength and had mechanical strength with no practical problems.

[0051]

The present invention is a spunbonded non-woven fabric composed of multifilament yarns, and the total fineness of the multifilament yarns can be obtained by appropriately selecting the fineness and the number of constituent fibers of the multifilament yarns. Therefore, it is possible to expect a wide variety of required performances that cannot be dealt with by the conventional spunbonded non-woven fabric in which monofilaments are separately deposited. That is, in the past, it was difficult to manufacture a spunbonded nonwoven fabric composed of single fibers exceeding 15 decitex from the viewpoint of operation, etc., but multifilament yarn is adopted as a unit of the constituent fibers of the spunbonded nonwoven fabric, and the total fineness is By using a multifilament yarn having a diameter of more than 15 decitex, it is possible to obtain a spunbonded non-woven fabric which can satisfy both mechanical strength and good air permeability and translucency at the same time. Moreover, since the total fineness of the multifilament yarn can be appropriately selected, it is possible to make the total fineness extremely large, and it is also possible to impart excellent rigidity to the nonwoven fabric.

Since the spunbonded nonwoven fabric of the present invention is composed of multifilament yarn, which is an aggregate of a plurality of single fibers, it is particularly excellent in tear strength.

The spunbonded non-woven fabric made of the multifilament yarn of the present invention has a wide range of selecting the fineness of the single fiber, the number of constituent fibers, and the total fineness of the multifilament yarn as described above. By selecting, it can be expected to satisfy various required performances according to various uses, such as construction and civil engineering, industrial materials such as vehicles, medical materials, sanitary materials, daily living materials, agriculture and gardening. It can be suitably used for various uses in various fields such as forestry materials.

Claims (8)

[Claims] 1. A multifilament yarn comprising a multifilament yarn made of a thermoplastic polymer, wherein the multifilament yarns retain their shape by being heat-bonded to each other. Spunbond non-woven fabric made of. 2. The spunbonded non-woven fabric made of the multifilament yarn according to claim 1, wherein the multifilament yarn has a twist. 3. In the multifilament yarn, the single fibers constituting the multifilament yarn are fused by melting or softening a part of the surface of the thermoplastic polymer constituting the single fiber. A spunbond nonwoven fabric comprising the multifilament yarn according to claim 1 or 2. 4. The total fineness of the multifilament yarn is 15 decitex or more.
A spunbonded non-woven fabric comprising the multifilament yarn according to any one of 1. 5. The single fiber constituting the multifilament yarn is a core-sheath type composite fiber in which a high melting point polymer is arranged in a core component and a low melting point polymer is arranged in a sheath component. A spunbond nonwoven fabric comprising the multifilament yarn according to any one of claims 1 to 4. 6. A thermoplastic polymer is melt-spun, a spun yarn is introduced into an air sucker, towed and drawn, and a multifilament yarn in a state in which single filaments are bundled is discharged from the air sucker, A method for producing a spunbonded nonwoven fabric composed of multifilament yarns, which comprises depositing filament yarns on a movable collection surface to form a web composed of multifilament yarns, and then thermally bonding the multifilament yarns together by heat treatment. . 7. The method for producing a spunbonded non-woven fabric comprising multifilament yarns according to claim 6, wherein the multifilament yarns are made by converging single fibers by twisting in an air sucker. 8. A spunbonded non-woven fabric comprising multifilament yarn according to claim 6 or 7, wherein single fibers are fused to each other before being introduced into air sucker or in air sucker to form a multifilament yarn. Production method.