JPH0841767A - Nonwoven fabric of composite structure and production of the same - Google Patents

Abstract

PURPOSE:To produce a nonwoven fabric free from the separation of its layers and suitable for a thermal adhesion processing to produce a bag. CONSTITUTION:This composite structure nonwoven fabric comprises conjugate filaments whose sheath and core parts comprise the first polymer component and the second polymer component having a higher melting point by 20 deg.C than that of the first polymer component, respectively, and other filaments as the third polymer component having a higher melting point by 20 deg.C than that of the first polymer. A part 6 comprisingly only the conjugate filaments, a part 7 comprising the conjugate filaments and other filaments in a (conjugate filaments)/(other filaments) weight ratio (g/cm<3>) of 10/90 to 50/50per unit volume in a mutually interlaced state, and a part 8 comprising the other filaments are arranged in this order along the thickness direction of the nonwoven fabric.

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 having a composite structure composed of long fibers and a method for producing the same, and particularly to a non-woven fabric having a long fiber composite structure suitable for producing a bag by heat bonding and a method for producing the same. Regarding

[0002]

2. Description of the Related Art Conventionally, a nonwoven fabric made of long fibers made of a thermoplastic polymer has been subjected to a heat-bonding process and pasted together to produce a bag. That is, a non-woven fabric composed of long fibers composed of a thermoplastic polymer can be pasted by thermal bonding without using an adhesive when manufacturing a bag, and can be efficiently manufactured. Widely used as a material for.

[0003]

However, when a bag is manufactured by this heat-bonding process, since it is heated and pressure-bonded at a temperature higher than the melting point of the polymer constituting the fiber, the bag-making process takes a long time. When the manufacturing apparatus is operated, there is a problem that the polymer melts and adheres to the heater, resulting in deterioration of product quality and yield.

As a measure against this, a non-woven fabric is composed of two kinds of filaments having different melting points, and a two-layer structure in which the melting point on the front surface side is lower than the melting point on the back surface side is used, so that the bag making apparatus can be used for a long time. It is possible to obtain a non-woven fabric that can be driven over.

By the way, when a non-woven fabric having such a two-layer structure is produced, filaments having different melting points are deposited in two layers and heat-pressed and fixed to each other. However, in the non-woven fabric thus obtained, the melting points of the filaments constituting the non-woven fabric are different on the front surface and the back surface, so that the high-melting-point side is not sufficiently thermocompressed and the peel strength is low. This is because, if the pressure contact temperature is low, the pressure contact on the high melting point side becomes insufficient, so it is necessary to increase the pressure contact temperature.
This is because if the pressure welding temperature is increased, a problem in manufacturing such that the low melting point side is fused to the pressure welding device occurs, and therefore the temperature cannot be set too high.

Therefore, there is a countermeasure for changing the temperature of the pressure welding device between the low melting point side and the high melting point side, but in this case, in order to sufficiently press the high melting point side, the pressure welding of the high melting point side is performed. The temperature needs to be higher than the condition under which a non-woven fabric consisting of a high melting point component alone is pressed. However, since the normal pressure contact temperature is close to the melting point of the fibers that make up the filament,
Higher temperatures lead to thermal degradation of the filament. Usually, the high melting point component is responsible for the strength of the non-woven fabric, so increasing the pressure contact temperature to sufficiently press the high melting point face always involves a risk of lowering the strength of the non-woven fabric. Therefore, there is a limit to raising the pressure contact temperature,
A conventional two-layered non-woven fabric having different melting points on the front and back has insufficient peeling strength due to insufficient pressure contact between layers.

That is, in the conventional method in which two kinds of non-woven fabrics are superposed and thermocompression-bonded, the peeling strength is largely dependent on the compatibility between the thermoplastic polymers constituting these two kinds of non-woven fabrics. However, even if pressure bonding is performed at a temperature close to the melting point, it is impossible to bond in a completely fused state.

The present invention solves the problems of the conventional non-woven fabric having a heat-adhesive layer on one side and is suitable for producing a bag by laminating by a heat-adhesion process, and moreover, the peel strength between layers is high. An object of the present invention is to provide a non-woven fabric having a high composite structure and a manufacturing method thereof.

[0009]

In order to solve the above problems, a nonwoven fabric having a composite structure according to the present invention has a first polymer component as a sheath portion and has a melting point of 20 ° C. or more higher than that of the first polymer component. A composite long fiber having a second polymer component having a high melting point as a core, and another long fiber made of a third polymer component having a melting point of 20 ° C. or more higher than that of the first polymer component, Along the thickness direction, the fiber existence ratio (weight ratio) (g / cm ³ ) of the part constituted only by the composite long fibers and the composite long fibers per unit volume to other long fibers is ( Composite long fiber) / (other long fiber) = 10/90 to 50/50, and is composed only of the part where the composite long fiber and the other long fiber are entangled with each other and the other long fiber. It is characterized in that the part and the part exist in this order.

Further, in the method for producing a non-woven fabric having a composite structure of the present invention, the first polymer component is used as the sheath portion, and the second polymer having a melting point of 20 ° C. or more higher than that of the first polymer component is used. The other continuous fiber formed by using a composite continuous fiber having a core component and another continuous fiber composed of a third polymer component having a melting point of 20 ° C. or more higher than that of the first polymer component By depositing fiber groups on a conveyor net on a web former and ejecting a part of the opened composite long fiber groups toward the other long fiber groups, the composite long fibers per unit volume Abundance ratio (weight ratio) between the and other long fibers (g /
cm ³ ) is (composite filament) / (other filament) = 10 /
90-50 / 50, to form a mixed portion of both fibers obtained by intertwining the composite continuous fiber and another continuous fiber,
It is characterized in that the opened composite long fiber group is deposited on the mixed portion.

Next, the present invention will be described in detail. The non-woven fabric of the present invention comprises a composite long fiber having a first polymer component as a sheath portion and a second polymer component having a melting point of 20 ° C. or more higher than that of the first polymer component as a core portion, It is composed of another long fiber composed of a third polymer component having a melting point of 20 ° C. or higher than that of the first polymer component. And
As shown in FIG. 1, a portion 6 composed only of composite long fibers,
The portion 8 composed of only the other long fibers is configured to be stacked on each other via the portion 7 in which the composite long fibers and the other long fibers are mixed.

The first and second polymer components constituting the core-sheath composite long fibers each have a fiber-forming property and can be melt-spun by using an ordinary melt-spinning apparatus. Is. Examples of the combination of the first and second polymer components include polyamide-based and polyester-based, polyolefin-based and polyester-based, polyolefin-based and polyamide-based, polyester-based and polyester-based, polyolefin-based and polyolefin-based, and the like. . Among them, the amide polymer is nylon 6, nylon 46, nylon 66 or nylon 61.
0 and the like. Examples of the ester-based polymer include polyethylene terephthalate, polybutylene terephthalate, and a copolymer of diol and terephthalic acid / isophthalic acid. Examples of the olefin polymer include polypropylene, high-density polyethylene, linear low-density polyethylene, ethylene / propylene copolymer and the like. Then, each polymer component is selected so that the melting point difference between the first polymer component constituting the sheath component and the second polymer component constituting the core component is 20 ° C. or more. These first and second polymer components include the usual extinguishing materials, heat stabilizers,
Additives such as pigments or polymer crystallization accelerators may be added.

In this composite continuous fiber, the second polymer component of the core portion needs to have a melting point of 20 ° C. or higher than the first polymer component of the sheath portion. Second polymer component and first
When the difference in melting point from the polymer component is less than 20 ° C., the polymer component of the core portion on the high melting point side is thermally deteriorated when the fibers of the web are subjected to thermal pressure contact at least partially with the heating roll. As a result, the strength of the non-woven fabric is reduced, and there is no point in making it into a composite long fiber, which is not preferable.

The third polymer component constituting the other long fibers must have fiber-forming properties and be capable of being melt-spun using a normal melt-spinning apparatus. For example, polyamide-based, polyester-based, polyolefin-based, etc. may be mentioned. Among these, examples of the amide polymer include nylon 6, nylon 46, nylon 66, nylon 610 and the like. Examples of the ester-based polymer include polyethylene terephthalate, polybutylene terephthalate, and a copolymer of diol and terephthalic acid / isophthalic acid. Examples of the olefin polymer include polypropylene, high-density polyethylene, linear low-density polyethylene, ethylene / propylene copolymer and the like. Additives such as ordinary quenching agents, heat stabilizers, pigments or polymer crystallization accelerators may be added to these third polymer components.

In the other long fibers, the third polymer component needs to have a melting point higher than that of the first polymer component in the composite long fibers by 20 ° C. or more. If the melting point difference between the third polymer component and the first polymer component is less than 20 ° C., for example, when a bag is produced by subjecting a nonwoven fabric to thermal bonding, the fibers on the heater side of the bag making machine. The difference in melting point between the polymer that constitutes the polymer and the polymer that constitutes the fiber on the non-heater side, that is, the adhesive surface side is small, and the polymer melts and adheres to the heater when heated at high temperature and subjected to pressure bonding treatment. This is not preferable because it causes a problem of deterioration in quality and yield.

Therefore, the composite continuous fiber of the present invention is composed of the above-mentioned various polymers. Particularly preferred as the first polymer component therefor is high-density polyethylene,
It is an olefin polymer such as linear low density polyethylene or ethylene / propylene copolymer. Particularly preferred as the second polymer component are ester-based polymers such as polyethylene terephthalate and polybutylene terephthalate, and amide-based polymers. The other long fibers are also composed of the above-mentioned various polymers.
Particularly preferable as the polymer component of (1) are polypropylene, polyethylene terephthalate, polybutylene terephthalate, ester type polymers such as diol and terephthalic acid / isophthalic acid copolymers, and amide type polymers.

The single yarn fineness of the above-mentioned composite long fibers and other long fibers is not particularly limited, but when it is extremely small, a unique texture is exhibited but productivity is lowered, which is not preferable. On the other hand, when it is extremely large, when it is made into a non-woven fabric, the flexibility is lowered and the texture becomes worse, which is not preferable. Generally, it is good to set it to about 2 to 10 denier.

In the non-woven fabric of the present invention, a part 6 composed of only the composite long fibers and a part 8 composed of only the other long fibers are interposed via a part 7 in which the composite long fibers and the other long fibers are mixed. And are stacked on top of each other. In addition, there is no clear boundary between the mixed portion 7 and the portion 8 made of only long fibers.

That is, in the nonwoven fabric of the present invention, the first polymer component having the lowest melting point, which is a constituent component of the composite filament, is present on one surface of the nonwoven fabric, that is, the surface on which the composite filament is exposed. On the other hand, the other surface of the non-woven fabric, that is, the surface where the other long fibers are exposed, has a melting point of 20 ° C. higher than that of the first polymer component, which is a constituent component of the long filaments and is a constituent component of the composite long fibers. The higher third polymer component is present.

Therefore, when the fibers of the web are partially heat-pressed by the heating roll, the third polymer component having a high melting point is not thermally deteriorated, so that the strength of the nonwoven fabric is lowered, Alternatively, the non-woven fabric does not shrink due to heat shrinkage to reduce the dimensional stability. Further, when the non-woven fabric is subjected to a heat-bonding process to produce a bag, when the heat-bonding process is applied to the side of the composite long fiber, the presence of the first polymer component having the lowest melting point,
Because it can be sufficiently heat-bonded even at low processing temperatures,
The polymer does not melt and adhere to the heater, resulting in a reduction in product quality and a reduction in yield.

Further, in the mixed portion 7 of the composite continuous fiber and the other continuous fiber, the fiber existence ratio (weight ratio) (g / cm ³ ) of the composite continuous fiber and the other continuous fiber per unit volume is
(Composite long fiber) / (other long fiber) = 10/90 to 50 /
By setting the ratio to 50, it is possible to prevent the first polymer component having the lowest melting point from oozing out onto the surface of the non-woven fabric in the portion where the portion made of other long fibers is exposed. Each part 6, 8, 7
FIG. 2 shows the distribution ratio of each long fiber in.

As the weight of the nonwoven fabric becomes low, the first polymer component having a low melting point easily exudes onto the surface of the nonwoven fabric where the portion 8 composed of other long fibers is exposed. Therefore, the mixing ratio of the fibers is (composite long fiber) / (other long fiber) = 1 due to the basis weight of the non-woven fabric having a composite structure to be produced.
It is arbitrarily determined within the range of 0/90 to 50/50. When the mixing ratio is less than 10/90, the part 6 composed only of the composite long fibers and the part 8 composed only of the other long fibers are easily separated from each other. Further, when the mixing ratio exceeds 50/50, the low-melting-point first polymer component oozes on the surface of the nonwoven fabric where the portion 8 made of other long fibers is exposed.

The method for producing the nonwoven fabric of the present invention will be described with reference to FIG. In FIG. 3, the opening devices 1a, 1b, 1
As c, an apparatus using a method in which a filament group is passed through a corona discharge electric field together with a pulling air flow to be charged is illustrated. That is, in the fiber opening device 1 using this corona discharge generating unit, the long fiber group B composed of the other long fibers is opened, and this is vertically deposited on the conveyor net of the web former 2.

Next, in the mixed portion of the composite continuous fiber and the other continuous fiber, the fiber existence ratio (weight ratio) of the composite continuous fiber and the other continuous fiber per unit volume (g / cm ³ ) is ( A part of the composite long fiber group A is opened by the opening device 1b so that the composite long fiber) / (other long fiber) = 10/90 to 50/50, and the web former 2 advances this. From the lower side of the direction, it is jetted together with the air flow in an oblique direction with respect to the net conveyor, toward the deposition portion of the long fiber group B. Thus, the fibers of the composite long fiber group A are entangled with the fibers of the long fiber group B.

The jetting angle is preferably 30 ° to 85 ° with respect to the moving direction of the long fiber group B. When a part of the composite long fiber group A is jetted toward the accumulated portion of the long fiber group B at an angle of less than 30 °, not only the entanglement of the fibers does not work well due to the mutual interference of air flows, but also the long fiber group B This is not preferable because it deteriorates the opened state of the fiber. When the composite long fiber group A is ejected from the lower part of the net conveyor toward the portion where suction is performed in order to deposit the fibers of the long fiber group B on the net conveyor, both long fiber groups A and B are ejected at the same portion. Therefore, the fibers of the long filament group B can be entangled without disturbing the open state of the fibers of the long filament group B.

At this stage, on the conveyor net, a portion in which the composite long fiber group A and the long fiber group B are entangled with each other is formed on the upper part of the part consisting of the long fiber group B only. By stacking the remaining composite long fiber group A on this net in the same manner as the long fiber group B from the direction perpendicular to the net conveyor, it is possible to form a non-woven web configured such that they are stacked on top of each other. .

The non-woven webs 3 in the stacked state formed in this manner are separated from the composite long fiber group A and the long continuous fiber group B by a portion between the composite long fiber group A only and the long fiber group B only. It has a portion where the fiber group B is entangled with each other. For this reason, there is no clear boundary surface between the part consisting of the composite long fiber group A and the part consisting of only the long fiber group B.
For this reason, the portion where the composite long fiber group A and the long fiber group B are entangled with each other is only the part consisting of the long composite fiber group A and the long fiber group B at the time of thermocompression bonding by the thermocompression bonding device 4 immediately thereafter. The non-woven fabric 5 having a composite structure that does not easily peel off can be obtained because the non-woven fabric 5 acts as a bridge between the non-woven fabric.

When carrying out this pressure welding method, although not particularly limited, a normal heat pressure welding apparatus such as a heat pressure welding apparatus having a pair of flat rolls or a heat pressure welding apparatus having an embossing roll and a flat roll is used. The device 4 can be preferably used. At this time, the temperature of each roll is preferably lower than the melting point of the polymer on the side in contact with each roll.

[0029]

When the nonwoven fabric of the present invention is heat-bonded to produce a bag, heat-bonding is applied to the side of the composite long fiber having the core-sheath structure including the sheath made of the low-melting first polymer component. And, even if the processing temperature is low, it can be sufficiently heat-bonded,
For this reason, the polymer does not melt and adhere to the heater and the quality and yield of the product are not deteriorated. In addition, a mixed portion of these composite long fibers and other long fibers is interposed between a portion formed of only the composite long fibers and a portion formed of only the other long fibers, and is mixed with a portion formed of only the other long fibers. Since the stacking is performed without a clear boundary between the part and the part, peeling between the part consisting only of these composite long fibers and the part consisting only of other long fibers is prevented, and the processing step There is no peeling inside. Furthermore, by using a composite long fiber having a core-sheath structure, when heat-bonding is performed with another long fiber to form a nonwoven fabric, the sheath part on the low melting point side of the composite long fiber contributes to the heat-pressure welding. However, at that time, the core portion on the high melting point side is less thermally deteriorated. Therefore, the strength of the obtained nonwoven fabric is high, breakage is unlikely to occur, and the flexibility of the nonwoven fabric is secured.

[0030]

Embodiments of the present invention will be described below. First, the measurement methods of the numerical values quoted in the examples will be summarized.

That is, the intrinsic viscosity index of polyethylene terephthalate was measured at a concentration of 0.5 g / 100 ml and a temperature of 20 ° C. using a weight mixed solvent of phenol and ethane tetrachloride.

The melting point of the polymer is DS manufactured by Perkin Elma Co., Ltd.
Using a C-2 type differential scanning calorimeter, a sample amount of about 5 mg,
It was based on the temperature showing the maximum value of the melting endothermic peak obtained by measuring the scanning rate at 20 ° C./min.

The tensile strength was measured according to JIS-L-1096 with a sample length of 5 cm × 20 cm, using a constant-speed extension type tensile tester (Tensilon RTM-500 manufactured by Orientec). Peel strength is in accordance with JIS-L-1089, sample length 3 cm x 20 cm
Was measured by a constant speed extension type tensile tester (Tensilon RTM-500 manufactured by Orientec Co., Ltd.). Example 1 Spin hole group consisting of 228 single component spin holes and 228
A melt spinning apparatus having a spinning hole group consisting of individual core-sheath type composite spinning holes was used. From a single-component spinning hole, a long fiber group having a circular cross section and having a fineness of 3 denier and made of a polyethylene terephthalate polymer having an intrinsic viscosity of 0.70 and a melting point of 260 ° C. was spun. Further, from the composite spinning hole, the above polyethylene terephthalate polymer is used as a core component, and a high density polyethylene polymer having a nominal melt index of 20 and a melting point of 131 ° C. is used as a sheath component, a fineness of 3 denier and a core-sheath weight ratio of 1: 1. The composite long fiber group having the core-sheath structure was spun. The spun long fiber group and the composite long fiber group were pulled together with an air flow by a plurality of air jets arranged below the long fiber group and the composite long fiber group. Next, as shown in FIG. 3, after the low melting point core-sheath type composite long fiber group A and the high melting point long fiber group B are opened by the respective opening devices 1a, 1b, 1c, The high melting point filament group B was deposited on the net conveyor of the web former 2. Then, the fiber existence ratio (weight ratio) (g / cm ³ ) of the composite continuous fiber and the other continuous fiber per unit volume in the mixed portion of the obtained nonwoven fabric 5 is
A part of the composite long fiber group A is directed toward the deposited portion of the high melting point long fiber group B so that (composite long fiber) / (other long fiber) = 15/85, and the high melting point long fiber The fibers were entangled with each other by being jetted together with the air flow at an angle of 60 degrees with respect to the jetting direction of group B. Then, the remaining low melting point core-sheath type composite long fiber group A was redeposited on the non-woven web having fiber entanglement to form a web. The web was hot pressed using a hot pressing device 4 having a flat roll and an embossing roll. At this time, the temperature of the flat roll was set to 235 ° C and the temperature of the embossing roll was set to 90 ° C. As a result, a nonwoven fabric 5 having a composite structure with a basis weight of 30 g / m ² was obtained. Table 1 shows the measurement results of the characteristics of the obtained non-woven fabric 5.
Shown in

[0034]

[Table 1]

Example 2 Using the same core-sheath type composite continuous fiber group A and other continuous fiber group B as in Example 1, the composite continuous fiber per unit volume in the mixed portion and the other continuous fiber were used. Existence ratio (weight ratio) (g / cm ³ )
Was set to (composite long fiber) / (other long fiber) = 30/70. Otherwise in the same manner as in Example 1, a non-woven fabric having a composite structure with a basis weight of 50 g / m ² was obtained. Table 1 shows the measurement results of the characteristics of the obtained nonwoven fabric. Example 3 Using the same core-sheath type composite continuous fiber group A as in Example 1 and another continuous fiber group B, the fiber existence ratio of the composite continuous fiber and other continuous fiber per unit volume in the mixed portion ( Weight ratio) (g / cm ³ )
Was set to (composite filament) / (other filament) = 50/50. Otherwise in the same manner as in Example 1, a non-woven fabric having a composite structure with a basis weight of 70 g / m ² was obtained. Table 1 shows the measurement results of the characteristics of the obtained nonwoven fabric. Example 4 The core component of the low melting point composite long fiber group A in Example 1 was changed to
A polypropylene having a nominal melt index of 30 and a melting point of 161 ° C. was used. Further, the fiber existence ratio (weight ratio) of the composite continuous fiber and the other continuous fiber per unit volume in the mixed portion (g /
cm ³ ) is (composite filament) / (other filament) = 30 /
I set it to 70. Otherwise in the same manner as in Example 1, a non-woven fabric having a composite structure with a basis weight of 50 g / m ² was obtained. Table 1 shows the measurement results of the characteristics of the obtained nonwoven fabric. Example 5 The high melting point long fiber group B in Example 1 was changed to polypropylene having a nominal melt index of 30 and a melting point of 161 ° C. Further, the fiber existence ratio (weight ratio) (g / cm ³ ) of the composite continuous fiber and other continuous fiber per unit volume in the mixed portion is
(Composite long fiber) / (other long fiber) = 30/70. Further, the flat roll temperature was set to 210 ° C. Other than that, it is the same as that of Example 1, and is a basis weight of 50 g / m.
A non-woven fabric having a composite structure of ² was obtained. Table 1 shows the measurement results of the characteristics of the obtained nonwoven fabric. Comparative Example 1 Using the same core-sheath type composite filament group A and filament group B as in Example 1, the filament group B on the high melting point side was deposited on the net conveyor of the web former 2. However, the composite long fiber group A is simply deposited on the non-woven web composed of the long fiber group B without entanglement of a part of the low melting point side composite long fiber group A with the high melting point side long fiber group B. Was obtained. Thereafter, pressure contact was performed in the same manner as in Example 1 to obtain a laminated nonwoven fabric having a basis weight of 50 g / m ² , and the measurement results of the properties of the obtained laminated nonwoven fabric are shown in Table 1. Comparative Example 2 Using the same core-sheath type composite continuous fiber group A as in Example 1 and another continuous fiber group B, the fiber existence ratio of the composite continuous fiber and other continuous fiber per unit volume in the mixed portion ( Weight ratio) (g / cm ³ )
Was set to (composite long fiber) / (other long fiber) = 80/20. Otherwise in the same manner as in Example 1, a non-woven fabric having a composite structure with a basis weight of 50 g / m ² was obtained. Table 1 shows the measurement results of the characteristics of the obtained nonwoven fabric. Comparative Example 3 The fiber existence ratio (weight ratio) (g / cm ³ ) of the composite continuous fiber and the other continuous fiber per unit volume in the mixed portion was (composite continuous fiber) / (other continuous fiber) = 65. It became / 35. Other than that, it is the same as that of the comparative example 2, and is a basis weight of 50 g / m.
A non-woven fabric having a composite structure of ² was obtained. Table 1 shows the measurement results of the characteristics of the obtained nonwoven fabric.

As is clear from Table 1, in Examples 1 to 5, the low melting point core-sheath type composite long fiber group A and the other high melting point long fiber group B are merely thermocompressed. Not
Since both of them have a portion entangled with each other, a good non-woven fabric having high peel strength was obtained. Further, the constituent components of the composite long fiber group A did not exude to the surface of the portion composed of the other long fiber group B.

In Comparative Example 1, the composite continuous fiber group A and the other continuous fiber group B were simply heat-pressed, and they were not entangled with each other, so that the peel strength between them was low, which was satisfactory. It wasn't going.

In Comparative Example 2, since the abundance ratio of the low melting point composite long fibers was remarkably high in the mixed portion as compared with the other high melting point long fibers, the composite long fiber groups were formed on the surface of the fibers of the other long fiber group B. The polymer of the sheath component A was coated. For this reason, peeling did not occur, and the sheath component of the composite long fiber group A exuded on the surface of the other long fiber group B. As a result, the function as a non-woven fabric having a stacked structure in which a melting point difference was provided between the low melting point composite long fiber group A and the high melting point long fiber group B was lost.

In Comparative Example 3, the abundance ratio of the low melting point composite long fibers was not as high as that of Comparative Example 2, but it was still higher than those of Examples 1 to 3, so that the low melting point composite long fibers were also present. Exudation of the sheath component of the fiber group A was observed. Similarly, neither fiber group A nor B peeled off.

[0040]

As described above, according to the non-woven fabric having the composite structure and the method for producing the same according to the present invention, the part composed only of the composite long fiber of the core-sheath structure and the part composed only of other long fibers. In between, it is possible to obtain a nonwoven fabric having a portion in which these composite long fibers and other long fibers are entangled with each other, and since this nonwoven fabric has the entangled portions of both the long fibers,
The peel strength is much higher than that of conventional laminated non-woven fabrics. Therefore, it is possible to actively use in fields where it could not be used due to the fact that peeling is easy until now. For example, when a bag is produced by applying a heat-bonding process, if the heat-bonding process is performed on the side of the composite filament having a core-sheath structure including a sheath portion made of the low-melting first polymer component, the processing temperature is low. It is possible to surely prevent the polymer from melting and adhering to the heater and deteriorating the quality and yield of the product. Further, by using the composite long fibers having a core-sheath structure, when the heat-bonding is performed with other long fibers to form the nonwoven fabric, the sheath part on the low melting point side of the composite long-fibers contributes to the heat-pressure welding. However, at that time, the core portion on the high melting point side is less thermally deteriorated, so that the obtained nonwoven fabric has high strength and is less likely to break, and the flexibility of the nonwoven fabric can be secured.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing an example of a nonwoven fabric having a composite structure according to the present invention.

FIG. 2 is a cross-sectional view schematically showing a fiber distribution state in the cross section of the nonwoven fabric.

FIG. 3 is a diagram schematically showing an example of a method for manufacturing a nonwoven fabric having a composite structure according to the present invention.

[Explanation of symbols]

 1a Fiber-spreading device 1b Fiber-spreading device 1c Fiber-spreading device 2 Web former 6 A part composed only of composite long fibers 7 A part in which composite long fibers and other long fibers are mixed 8 Composed only of other long fibers Part A Composite long fiber group B Other long fiber group

Claims (2)

[Claims] 1. A composite long fiber comprising a first polymer component as a sheath portion and a second polymer component having a melting point of 20 ° C. or higher higher than that of the first polymer component as a core portion, First
Of the third polymer component having a melting point of 20 ° C. or more higher than that of the polymer component, and a unit volume along the thickness direction composed of only the composite filament. The fiber existence ratio (weight ratio) (g / cm ³ ) of the composite continuous fiber and the other continuous fiber per unit is (composite continuous fiber) / (other continuous fiber) = 10/90 to 50/50 A non-woven fabric having a composite structure, characterized in that a portion in which these composite long fibers and other long fibers are entangled with each other and a portion formed only of the other long fibers are present in this order. 2. A composite long fiber comprising a first polymer component as a sheath and a core of a second polymer component having a melting point of 20 ° C. or higher than that of the first polymer component, First
Other long fibers comprising a third polymer component having a melting point of 20 ° C. or more higher than that of the above polymer component are used to deposit the other opened long fiber group on a conveyor net on a web former. , A part of the opened composite long fiber group is ejected toward the other long fiber group, whereby the fiber existence ratio (weight ratio) of the composite long fiber and the other long fiber per unit volume Both fibers obtained by intertwining the composite continuous fiber and the other continuous fiber so that (g / cm ³ ) is (composite continuous fiber) / (other continuous fiber) = 10/90 to 50/50. And a composite long fiber group that has been opened is deposited on the mixed portion.