JPH0931857A - Laminated nonwoven fabric and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain laminated nonwoven fabric excellent in tensile strength, flexibility, filter characteristics and water absorption by successively laminating polypropylene filament nonwoven fabric, polypropylene ultra-fine fiber nonwoven fabric and cotton fiber nonwoven fabric and subsequently integrating the laminated nonwoven fabrics at spot-like fused regions. SOLUTION: Polypropylene filament nonwoven fabric having a fineness of 2-10de and a METSUKE of 5-50g/m<2> and formed by a spun-bonding method, polypropylene ultra-fine fiber nonwoven fabric having a fineness of <=0.2de and a METSUKE of 10-120g/m<2> and formed by a melt-blown method, and cotton fiber nonwoven fabric formed by subjecting cotton card webs to a needle punching treatment to integrally interlace the constituting cotton fibers with each other are successively laminated to each other, and subsequently integrated at plural spot-like fused regions 3 with an ultrasonic fusing machine. In the spot-like fused regions 3, the filament melted parts 4 and the ultra-fine fiber melted parts 2 are fused to each other to melt-integrate the flament nonwoven fabric to the ultra-fine fiber nonwoven fabric, and simultaneously the cotton fibers 1 are embedded in the ultra-fine fiber melted parts 2 to integrate the cotton fiber nonwoven fabric with the ultra-fine fiber nonwoven fabric.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polypropylene-based long fiber nonwoven fabric, a polypropylene-based ultrafine fiber nonwoven fabric,
TECHNICAL FIELD The present invention relates to a laminated non-woven fabric in which a cotton fiber non-woven fabric is laminated in order, and a method for producing the same, and particularly relates to a laminated non-woven fabric having high delamination strength between an ultrafine fiber non-woven fabric and a cotton fiber non-woven fabric and hardly delaminating, and a method for producing the same. The present invention also relates to a laminated nonwoven fabric excellent in tensile strength, flexibility, anti-fluffing property, filter characteristics and water absorption, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a laminated non-woven fabric is known in which various non-woven fabrics having different fiber materials are laminated and the physical properties of each non-woven fabric are exhibited. For example, there is known a laminated non-woven fabric in which a non-woven fabric made of natural fibers and a non-woven fabric made of thermoplastic fibers are laminated to exhibit good water absorption of the natural fibers and good mechanical properties (tensile strength, etc.) of the thermoplastic fibers. Has been.

For laminating the natural fiber nonwoven fabric and the thermoplastic fiber nonwoven fabric, for example, a method of laminating with an adhesive is known. However, when the adhesive is applied to the entire surface between the layers of the natural fiber nonwoven fabric and the thermoplastic fiber nonwoven fabric,
The breathability of the non-woven fabric was sometimes impaired.
Further, since the adhesive layer is formed, the flexibility of the entire laminated nonwoven fabric may be reduced. For this reason, the adhesive is not applied to the entire surface but is applied partially (for example, in spots) (Japanese Patent Publication No. 54-24506). However, in order to apply the adhesive partially and regularly, a complicated work is required. For example, the adhesive may be partially and evenly applied on the release paper in advance, the release paper may be laminated on the natural fiber nonwoven fabric, the adhesive may be transferred to the natural fiber nonwoven fabric, and then the release paper may be peeled off. It required a lot of troublesome work and was not a rational method.

Therefore, it is conceivable to laminate the natural fiber nonwoven fabric and the thermoplastic fiber nonwoven fabric by utilizing the plasticity of the thermoplastic fiber. That is, it is conceivable that the surface of the thermoplastic fiber is softened or melted to develop tackiness, and the tackiness causes the thermoplastic fiber and the natural fiber to adhere to each other. Sure, this is a reasonable method,
Depending on the material of the natural fiber or the thermoplastic fiber, strong adhesion may not be possible. That is, when the wettability of the natural fiber and the thermoplastic fiber is good (when the SP values are similar), strong adhesion can be realized by this method, but the wettability of both fibers is poor. In such a case (a case where there is a large difference in SP value), strong adhesion may not be realized. In some cases, the delamination strength between the natural fiber nonwoven fabric and the thermoplastic fiber nonwoven fabric is not increased. In particular, when cotton fibers are used as the natural fibers and polypropylene fibers are used as the thermoplastic fibers, it is impossible to realize strong adhesion, and the cotton fiber nonwoven fabric and the polypropylene fiber nonwoven fabric are It was difficult to obtain a laminated non-woven fabric having high delamination strength.

[0005]

Therefore, the inventors of the present invention do not mainly focus on adhering the natural fiber and the thermoplastic fiber by virtue of the adhesiveness of the thermoplastic fiber, but rather the fluidity of the thermoplastic fiber. By utilizing this fluidity to embed the natural fiber in the thermoplastic fiber, the natural fiber and the thermoplastic fiber are bonded to each other, thereby increasing the bonding force between the natural fiber and the thermoplastic fiber. However, it has been proposed to increase the delamination strength of a laminated nonwoven fabric composed of a natural fiber nonwoven fabric and a thermoplastic fiber nonwoven fabric (Japanese Patent Application No. 6-19375).
No. 9). That is, the invention of Japanese Patent Application No. 6-193759 discloses that a cotton fiber nonwoven fabric in which cotton fibers are entangled with each other is laminated on both sides of an ultrafine fiber nonwoven fabric made of polypropylene-based ultrafine fibers having a fineness of 0.2 denier or less. Which has a point-like fused area formed by directly joining the ultrafine fiber nonwoven fabric and the cotton fiber nonwoven fabric, and in the point-like fused area, the fusion portion of the ultrafine fibers is formed. The present invention relates to a laminated non-woven fabric, characterized in that the two fibers are bonded together with the cotton fibers embedded therein.

This laminated non-woven fabric is suitable because the ultra-fine fiber non-woven fabric and the cotton fiber non-woven fabric are firmly bonded to each other in the spot-shaped fusion bonded area, and the delamination strength is high. However, in the spot-shaped fused area, the amount of ultrafine fibers is
When the amount of the cotton fibers was extremely small compared to the amount of the cotton fibers, the fused portion of the ultrafine fibers for embedding the cotton fibers and holding the cotton fibers sometimes deteriorated the function.
That is, the thickness of the melted portion of the ultrafine fiber becomes thin, and the function of the cotton fiber as a matrix is deteriorated, and the matrix is relatively small during the handling of the laminated nonwoven fabric, so the matrix is damaged or destroyed. In the end, however, the delamination strength was sometimes reduced.

Therefore, the present invention is intended to prevent a decrease in delamination strength by reinforcing the melted portion of the ultrafine fiber which is the matrix of the cotton fiber. Specifically, on the other surface of the ultrafine fiber nonwoven fabric (the surface opposite to the one on which the cotton fiber nonwoven fabric is laminated), a fiber of the same type as the ultrafine fibers and having a fineness greater than that of the ultrafine fibers. The non-woven fabric obtained by accumulating the above is laminated, and the fusion portion of the fiber of the same kind is fused and integrated with the fusion portion of the ultrafine fiber to reinforce the fusion portion of the ultrafine fiber.

[0008]

That is, the present invention has a fineness of 2
A long-fiber non-woven fabric in which polypropylene-based long fibers of 10 denier are accumulated, an ultra-fine fiber non-woven fabric in which polypropylene micro-fibers having a fineness of 0.2 denier or less are accumulated, and a cotton-fiber non-woven fabric in which cotton fibers are entangled with each other A laminated non-woven fabric which is laminated in order, wherein the laminated non-woven fabric has dot-like fused regions provided at intervals,
In the point-like fused area, the long-fiber nonwoven fabric and the ultrafine-fiber nonwoven fabric are joined by fusion-bonding the fusion part of the polypropylene-based long fiber and the fusion part of the polypropylene-based ultrafine fiber. The present invention relates to a laminated non-woven fabric, wherein the ultra-fine fiber non-woven fabric and the cotton fiber non-woven fabric are bonded by embedding the cotton fiber in at least the fused portion of the polypropylene-based ultra-fine fiber, and a method for producing the same. It is a thing.

First, the long fiber nonwoven fabric used in the present invention will be described. This long-fiber non-woven fabric has a fineness of 2 to 1
It is made by accumulating 0 denier long fibers. The long fibers are formed of polypropylene polymer. As a polypropylene-based polymer,
Generally polypropylene is used. Other than polypropylene, those obtained by copolymerizing polypropylene with several% by weight of ethylene or other monomer can be used. It should be noted that the polypropylene-based polymer may include any additive such as a matting agent, a pigment, a flameproofing agent, a deodorant, an antistatic agent, an antioxidant, an ultraviolet absorber, etc. within a range that does not impair the object of the present invention. May be added.

The fineness of the long fibers formed of polypropylene polymer, that is, the polypropylene long fibers, is adjusted to be within the range of 2 to 10 denier. When the fineness of the polypropylene-based long fibers is less than 2 denier, the surface of the long fiber non-woven fabric tends to be fluffed, and it becomes difficult to obtain the laminated non-woven fabric intended by the present invention. Further, when the fineness of the polypropylene long fibers exceeds 10 denier, the long fibers themselves become coarse and rigid, and it becomes difficult to obtain a flexible laminated nonwoven fabric as the object of the present invention.

The long-fiber nonwoven fabric used in the present invention is
Generally, it can be easily obtained by the spun bond method. That is, a polypropylene-based long fiber is melt-spun using a conventionally known melt spinning machine, and after cooling with a blowing air using a conventionally known cooling device such as horizontal blowing or annular blowing, generally using an air sucker. , Pulled and thinned so that the desired fineness is obtained. Traction speed is 3000m / min or more,
Particularly, 3500 m / min or more is suitable for the mechanical performance of the long fiber nonwoven fabric. The long fibers discharged from the air sucker are generally charged and opened by passing through a corona discharge area in a high-voltage field or a frictional collision zone, and then opened on a moving deposition device such as a conveyor composed of a screen. The fibers are accumulated to obtain a fiber aggregate. Then, this fiber assembly is used as it is as a long-fiber nonwoven fabric, or is subjected to a heat calendering treatment on the entire surface or a heat embossing treatment on a part thereof to improve morphological stability and suppress fuzzing, and You may use it as a nonwoven fabric. The conditions for applying the heat calendar treatment or the heat embossing treatment are milder than the conditions for providing the dot-like fused regions in the laminated non-woven fabric, and the degree of pseudo-adhesion (pseudo-compression bonding) between the long fibers occurs. The following is preferable in order to secure the flexibility of the finally obtained laminated nonwoven fabric. This is because if the conditions such as thermal calendering are harsh, the fusion and fixing of the long fibers to each other is severe, and the fusion and fixing portion reduces the flexibility.

When the spunbond method is adopted, the polypropylene polymer is introduced into a melt spinning machine and melt-spun. The polypropylene polymer used at this time has a melt flow rate value (hereinafter, It is referred to as “MFR.” MFR is measured by the method described in ASTM-D1238 (L)) and is 20 to 10.
It is preferable to use 0 g / 10 min. MFR is 2
If less than 0 g / 10 min is used, a large amount of energy is required to draw and thin the long fibers immediately after melt spinning. Further, this makes it difficult to obtain polypropylene long fibers having a fineness (for example, about 2 to 5 denier). On the other hand, when the MFR exceeds 100 g / 10 minutes, the operability of melt spinning and the uniformity of long fibers are likely to decrease, and as a result, the appearance and mechanical performance of the long fiber nonwoven fabric are likely to be adversely affected. The spinning temperature during melt spinning is appropriately selected depending on the type of polypropylene-based polymer and its MFR, but is generally selected within the range of 200 to 270 ° C.

The unit weight of the long-fiber non-woven fabric is 5 to 50 g / m ^2.
It is preferably about 10 to 30 g / m ² , and more preferably about 10 to 30 g / m ² . When the basis weight is less than 5 g / m ² , the degree of dense overlap between the long fibers is low, the appearance becomes uneven, and the ultrafine fibers may scatter from the gaps between the long fibers. On the other hand, when the basis weight exceeds 50 g / m ² , the thickness tends to be too thick and the flexibility of the long-fiber nonwoven fabric tends to decrease, and as a result, the flexibility of the laminated nonwoven fabric also tends to decrease.

Next, the ultrafine fiber nonwoven fabric used in the present invention will be described. This fine fiber non-woven fabric has a fineness of 0.2.
It consists of ultrafine fibers of denier or less. And
This ultrafine fiber is formed of a polypropylene polymer. As the polypropylene-based polymer, the same one as used in obtaining the polypropylene-based long fibers described above is used. That is, polypropylene is generally used.
It is possible to use a product obtained by copolymerizing ethylene or other monomer of (3) with polypropylene. Further, as in the case of obtaining polypropylene-based long fibers, the polypropylene-based polymer may be added to the polypropylene-based polymer within the range that does not impair the object of the present invention. Agent,
Any additive such as an ultraviolet absorber may be added.

The fineness of the ultrafine fibers is 0.2 denier or less. If this fineness exceeds 0.2 denier, the pore size of the surface of the ultrafine fiber nonwoven fabric becomes large, and the filter performance (performance capable of removing fine dust) as the object of the present invention cannot be exhibited, so it is preferable. Absent. The fineness referred to in the present invention means the average fineness in both cases of long fibers and ultrafine fibers, and the fineness of each fiber (each long fiber or each ultrafine fiber) present in a unit area. Means the average value of.

A melt blown method is preferably used as a method for obtaining a nonwoven fabric made of polypropylene ultrafine fibers having a fineness of 0.2 denier or less. According to the melt blown method, unlike the spunbond method and the like, crystallization of the obtained fiber does not proceed so much (the degree of orientation of polymer chains is low), and the flowability of the polypropylene ultrafine fiber is increased by the action of ultrasonic waves. This is because it will be relatively high. That is, as a result, the cotton fibers are easily embedded in the polypropylene ultrafine fibers.

In order to obtain a polypropylene type ultrafine fiber nonwoven fabric by the melt blown method, the following method is generally adopted. That is, a polypropylene-based polymer is melted by a known spinning machine, and the pore diameter of the spinneret is 0.1 to 1 mm.
Discharge from the spinning hole of a certain degree. The discharged molten polypropylene-based polymer stream is discharged at a temperature higher by 20 to 50 ° C. than the melting temperature from a die in which discharge holes having a diameter of about 0.1 to 0.5 are arranged in a row. For example, it is pulled and thinned by a high-pressure heated air flow). Then, the polypropylene-based ultrafine fibers discharged in this way and finely (at this time, the fineness is 0.2 denier or less) are collected and accumulated on the moving collection surface, thereby obtaining the fineness. Is 0.
It is possible to obtain an ultrafine fiber nonwoven fabric composed of polypropylene ultrafine fibers having a denier of 2 or less.

In the melt blown method, the polypropylene polymer is melted by using a known spinning machine.
The polypropylene-based polymer used has an MFR of 100 to 8
It is preferably about 00 g / 10 minutes. MFR is 10
If it is less than 0 g / 10 minutes, a large amount of energy is required to thin the discharged yarn, and it tends to be difficult to obtain ultrafine fibers. On the other hand, if it exceeds 800 g / 10 minutes, the spinning operability and the uniformity of the ultrafine fibers are likely to be impaired. The spinning temperature is appropriately selected depending on the type of polypropylene-based polymer and the MFR, but is generally about 250 to 320 ° C. The flow rate of the high-pressure heated gas flow is preferably about 80 to 300 m / sec, and the jetting direction is preferably 15 to 45 degrees with respect to the spinning line direction.

The weight of the ultrafine fiber nonwoven fabric is 10 to 120 g.
/ M ² is preferable, and more preferably about ²⁰ to 100 g / m ² . When the basis weight is less than 10 g / m ² , the fiber density of the ultrafine fibers in the ultrafine fiber nonwoven fabric is low, the degree of dense superposition of the ultrafine fibers constituting the nonwoven fabric is low, and the formation of the ultrafine fiber nonwoven fabric itself and May impair filter performance. On the contrary, the basis weight is 120 g / m
^If it exceeds ² , although the filter performance is improved, the thickness tends to be too thick, and the flexibility of the ultrafine fiber nonwoven fabric tends to decrease, and as a result, the flexibility of the laminated nonwoven fabric tends to decrease. Further, the microfiber non-woven fabric itself is easily delaminated, and in order to prevent this, it is necessary to embed cotton fibers to the inside of the microfiber non-woven fabric, and embed it using an ultrasonic fusion machine. In this case, the processing speed must be slowed down and a large amount of ultrasonic energy must be required.

As the ultrafine fiber non-woven fabric used in the present invention, it is sufficient to simply use the ultrafine fiber nonwoven fabric in a state where polypropylene ultrafine fibers are accumulated and deposited. Further, in order to improve the morphological stability or to suppress the fluffing of the surface, thermal calendaring may be performed with a calender roll having a smooth surface, or instead of a calender roll having a smooth surface,
The heat embossing treatment may be performed using an embossing roll having an uneven surface. The conditions for applying the heat calendar treatment or the heat embossing treatment should be milder than the conditions for providing the dot-like fused areas in the laminated non-woven fabric, and the degree to which pseudo-adhesion (pseudo-compression bonding) occurs between the ultrafine fibers. The following is preferable in order to secure the flexibility of the finally obtained laminated nonwoven fabric. This is because if the conditions such as thermal calendering are harsh, the ultrafine fibers are strongly fused and fixed to each other, and the fusion and fixed portions reduce the flexibility.

Next, a cotton fiber non-woven fabric in which cotton fibers are entangled with each other will be described. As the cotton fibers, there can be used unbleached combed yarn, bleached bleached cotton, or fluff obtained from knitted fabrics. When using anti-wool as cotton fiber, a rag machine,
A knot breaker, a garnet machine, a turning machine, etc. can be used. The type and combination of anti-fluffing machines to be used depend on the fabric shape of the knitted fabric or the like to be fluffed and the thickness or twisting strength of the yarns forming the knitted fabric, but a plurality of the same anti-fluffing machines are used. It is more effective to connect them in series or use a combination of two or more anti-fluffing machines. Thus, the reason why the cotton fiber is used is to impart good water absorption to the obtained cotton fiber nonwoven fabric.

It is preferable that the defibration rate by the fluffing machine is in the range of 30 to 95%. If the defibration rate is less than 30%, a large number of undefibrated fibers (threads) are present in the web, and thus the surface of the cotton fiber nonwoven fabric may be rough. Further, when a large number of undisentangled fibers are present in the web, when the cotton fibers are entangled with each other in the high-pressure liquid flow, the high-pressure liquid flow hardly penetrates through the undisentangled fibers,
The confounding tends to be insufficient. On the other hand, if the defibration rate exceeds 95%, as a result that almost no defibrated fibers are present in the web, the friction coefficient of the web surface becomes small, and sufficient surface friction strength is obtained when laminating with the ultrafine fiber nonwoven fabric. It is difficult to obtain, and there is a tendency for slipperiness in the lamination process. The defibration rate referred to here is obtained by the following equation. That is, the defibration rate (%) = [(weight of woven fabric-weight of yarn) / weight of woven fabric] × 100.

The cotton fiber thus obtained is
Create a card web with a specific weight using a card machine. Instead of the card machine, a random webber or the like may be used to create the web. Then, by subjecting this web to needle punching treatment or high-pressure liquid flow treatment, a cotton fiber nonwoven fabric in which cotton fibers are entangled with each other can be obtained. As a web,
Various types can be adopted depending on the degree of arrangement of the cotton fibers. For example, a parallel card web in which cotton fibers are arranged in the machine direction of a card machine, a crosslay card web in which parallel card webs are cross-laid, a random web in which cotton fibers are randomly arranged, and a medium cotton fiber Semi-random webs that are random can be employed.
Further, when the laminated nonwoven fabric according to the present invention is developed as a material for clothing, it is preferable to adopt a web (cross-laid card web or random web) having a longitudinal / lateral tensile strength ratio of 1/1. .

The reason why the web is subjected to the needle punching treatment or the high-pressure liquid flow treatment is to entangle the cotton fibers constituting the web (in particular, to entangle three-dimensionally). The high pressure liquid flow treatment is generally performed under the following conditions. That is, the pore diameter is 0.05 to 1.5 mm, and particularly, 0.1.
Using a device in which 1 to 0.4 mm injection holes are arrayed in an example or a plurality of rows with a hole interval of 0.05 to 5 mm, a high pressure liquid having an injection pressure of 5 to 150 kg / cm ² G is injected from the injection holes, The webs placed on the porous support member are entangled between the cotton fibers by colliding the high-pressure liquid stream. The injection holes are preferably arranged in a row in a direction orthogonal to the direction of travel of the web. Also,
Generally, room temperature water or hot water is used as the high-pressure liquid. The distance between the injection hole and the web is preferably 1 to 15 cm. If this distance is less than 1 cm, the high pressure liquid flow may disturb the formation of the web.
On the other hand, when this distance exceeds 15 cm, the impact force when the high-pressure liquid collides with the web decreases, and it tends to be difficult to perform sufficient entanglement.

The treatment with the high-pressure liquid stream is preferably carried out in at least two stages. That is, as the first-stage treatment, the injection pressure of the high-pressure liquid flow is 5 to 40 kg / cm ²
When set to G, the web is subjected to a high pressure liquid flow treatment to pre-entangle the cotton fibers. In this first stage treatment, if the jet pressure of the liquid flow is less than 5 kg / cm ² G, it becomes difficult to pre-entangle the cotton fibers in the web with each other, and the morphological stability that can withstand the second stage treatment is stable. It becomes difficult to obtain the one with the property. On the other hand, if the jet pressure of the high-pressure liquid flow exceeds 40 kg / cm ² G, the movement of the cotton fibers in the web will become violent, and the texture of the web may be disturbed, or the web may have uneven spots. In the second step, the injection pressure of the high-pressure liquid flow is set to 50 to 15
The web is preliminarily entangled to form-stabilize the web, which is set to 0 kg / cm ² G, is subjected to a high-pressure liquid flow treatment, and is sufficiently entangled between the cotton fibers to densify the whole. In the second-stage treatment, the injection pressure of the high-pressure liquid stream was 50 kg.
If it is less than / cm ² G, it becomes difficult to give sufficient entanglement between the cotton fibers. On the contrary, when the injection pressure of the high-pressure liquid flow exceeds 150 kg / cm ² G, the entanglement becomes excessive and the densification progresses too much, tending to reduce the flexibility and bulkiness of the resulting cotton fiber nonwoven fabric. Occurs. Depending on the basis weight of the web, the high pressure liquid flow treatment of the third stage may be performed subsequent to the second stage treatment. The treatment in the third stage is preferably performed on the surface opposite to the web surface which has been subjected to the high pressure liquid flow treatment in the second stage. The injection pressure of the high-pressure liquid flow in the third stage process may be approximately the same as the injection pressure in the second stage process. By performing the treatment of the third stage, a cotton fiber nonwoven fabric densified on both sides can be obtained.

As the porous support member used when performing the high-pressure liquid flow treatment, for example, a wire net, a synthetic resin mesh screen, a perforated plate or the like is used. In short, any material can be used as long as it has a hole through which the high-pressure liquid flow passing through the web is discharged. Generally, when using a wire net or a mesh screen, the pore size is preferably 20 to 200 mesh. Pore size is 20
If it is less than the mesh, the pores are too large and the high pressure liquid flow passing through the web is discharged directly to the lower side without colliding with the porous support member. There is a risk of falling out of it.
On the other hand, if the pore size exceeds 200 mesh, it becomes difficult for the high-pressure liquid flow to pass through the porous support member, and the liquid may stay on the porous support member. Further, when trying to pass a high-pressure liquid flow through such a porous support member, the injection pressure of the high-pressure liquid flow must be increased, which disturbs the formation of the web or realizes a high injection pressure. Therefore, there is a tendency that the amount of energy used to do so increases and the production cost rises.

Since the web is impregnated with the liquid when the web is subjected to the high-pressure liquid flow treatment, it is necessary to remove the impregnated excess liquid (for example, excess water) after the high-pressure liquid flow treatment. For this removal, a known method is adopted, for example, a squeezing device such as a mangle roll is used to mechanically remove the impregnated excess liquid to some extent, and subsequently, a suction band hot-air circulating dryer or the like is used for drying. The device can be used to remove residual liquid to obtain a cotton fiber nonwoven fabric. Note that, in the above, the description has been centered on an example in which the cotton fibers are entangled three-dimensionally using a high pressure liquid flow, but in the present invention, a needle punching process is performed instead of the high pressure liquid flow process, As described above, a cotton fiber non-woven fabric in which cotton fibers are entangled three-dimensionally may be obtained. The reason why the cotton fibers in the cotton fiber nonwoven fabric are entangled with each other in this manner is to increase the tensile strength of the cotton fiber nonwoven fabric and to suppress fluffing.

The unit weight of the cotton fiber non-woven fabric used in the present invention is preferably about ²⁰ to 150 g / m ² , particularly 30.
It is more preferably about 100 g / m ² . Weight is 20g /
When it is less than m ² , the amount of cotton fibers in the cotton fiber nonwoven fabric is small, and there is a tendency that sufficient water absorption is not exhibited. On the contrary, when the fabric weight exceeds 150 g / m ² , the flexibility of the cotton fiber non-woven fabric itself tends to decrease,
The flexibility of the obtained laminated nonwoven fabric also tends to decrease.

The laminated non-woven fabric according to the present invention comprises the long-fiber non-woven fabric described above, the microfiber non-woven fabric described above, and the cotton-fiber non-woven fabric described above, which are laminated in this order. That is, the fine fiber non-woven fabric is used as the middle layer, the long fiber non-woven fabric is laminated on one side, and the cotton fiber non-woven fabric is laminated on the other side. On the surface of the long fiber non-woven fabric (the surface opposite to the surface in contact with the ultrafine fiber non-woven fabric) or the surface of the cotton fiber non-woven fabric (surface opposite to the surface in contact with the ultrafine fiber non-woven fabric), other non-woven fabrics or knitted fabrics are used. Sheet-like materials such as films and meshes may be laminated. The long fiber nonwoven fabric and the ultrafine fiber nonwoven fabric, and the ultrafine fiber nonwoven fabric and the cotton fiber nonwoven fabric are laminated so as to be directly joined (directly laminated), and are firmly joined (bonded) in the dot-shaped fusion zone 3 shown in FIG. ) Has been.

Then, in the spot-shaped fusion-bonded area 3, as shown in FIG. 2, the cotton fiber 1 is embedded in the melting portion 2 of the ultrafine fiber, and the cotton fiber 1 and the ultrafine fiber are bonded to each other. The ultrafine fiber nonwoven fabric and the cotton fiber nonwoven fabric are firmly bonded. In addition, the melting portion 2 of the ultrafine fibers
Is lined with the melting portion 4 of the long fiber, and the melting portion 2 and the melting portion 4 are fused and integrated. That is, both fibers are fused and integrated by softening or melting the long fibers and the ultrafine fibers, and the long fiber nonwoven fabric and the ultrafine fiber nonwoven fabric are joined. Although FIG. 2 shows a state in which the cotton fiber 1 is embedded only in the melting portion 2 of the ultrafine fiber,
In the present invention, the cotton fibers 1 may be embedded so as to reach the melting portion 4 of the long fiber through the melting portion 2 of the ultrafine fiber. As described above, the melted portion 2 of the ultrafine fiber in which the cotton fiber 1 is embedded and has the function of the matrix of the cotton fiber 1 is lined and reinforced by the melted portion 4 of the long fiber. Therefore, the fusion portion 2 of the ultrafine fibers in the present invention is
The function of the cotton fiber 1 as a matrix is effectively exhibited, and there is little risk that the matrix is damaged or destroyed during handling of the laminated nonwoven fabric. Therefore, delamination between the ultrafine fiber nonwoven fabric and the cotton fiber nonwoven fabric is less likely to occur. Since both the ultrafine fiber nonwoven fabric and the long fiber nonwoven fabric are made of fibers made of the same type of polypropylene polymer, it goes without saying that they are firmly bonded in the point fusion zone.

The plane shape of each dot-shaped fused area is circular,
Any shape such as an ellipse, a triangle, or a quadrangle can be adopted. Further, it is preferable that the area of each dot-shaped fused area is as small as possible. If this area is too large, the individual fused areas will be large, tending to reduce the flexibility of the laminated nonwoven. Furthermore, the total area of the dot-like fused regions is preferably about 4 to 50%, and more preferably about 8 to 25% with respect to the area of the laminated nonwoven fabric.
When the total area of the dot-like fused areas is less than 4%, the areas where the respective nonwoven fabrics are strongly bonded tend to decrease, and the delamination strength tends to decrease as a whole. On the contrary, when the total area exceeds 50%, the flexibility and bulkiness of the obtained laminated nonwoven fabric tend to be lowered.

As described above, in order to embed the cotton fiber in the melting portion of the ultrafine fiber and to fuse and integrate the melting portion of the long fiber and the melting portion of the ultrafine fiber to obtain the point-like fused area, Most preferably, a sonic fuser is used. For example, when a hot embossing device is used instead of the ultrasonic fusing machine, it is generally difficult to obtain the spot-shaped fusing area in such a state. This is because, as mentioned above, polypropylene-based ultrafine fibers and cotton fibers do not have very good wettability with each other, and even if a hot embossing device is used at high temperature and high linear pressure, the ultrafine fiber nonwoven fabric and cotton fibers The strong bond as obtained in the present invention cannot be obtained between the fibrous nonwoven fabric and the nonwoven fabric. The hot embossing device referred to here is a device consisting of a heated concavo-convex roll and a heating or normal-temperature smoothing roll, and a heat treatment applied from the concavo-convex roll by introducing a laminate between the both rolls. And a device that softens or melts the ultrafine fibers by the action of the pressure between the two rolls to exert the adhesiveness on the ultrafine fibers.

In the present invention, the ultrasonic fusion machine used as the most preferable apparatus is an ultrasonic oscillator having a frequency of about 20 KHZ, which is generally called a horn, and a point-shaped convex projection on the circumference. And a pattern roll provided. Then, by introducing a laminate (a long fiber non-woven fabric, an ultrafine fiber non-woven fabric and a cotton fiber non-woven fabric laminated in this order) between the ultrasonic oscillator and the pattern roll, the point-shaped fusion zone referred to in the present invention can be obtained. You can get it. That is, the ultrasonic fusion machine gives some kind of vibration to the polypropylene-based ultrafine fibers, and the frictional heat due to this vibration causes the ultrafine fibers to melt and exhibit a good flow state. Then, at this time, due to the linear pressure between the horn and the pattern roll, the cotton fibers in the web corresponding to the convex protrusions of the pattern roll are embedded in the melted portion in the fluidized state. That is, the point-shaped fused area is obtained. Further, similarly, the polypropylene-based long fibers also generate frictional heat due to vibration, and the long fibers are melted, and at the same time, fused and integrated with the melted ultrafine fibers, and the point-like fused area in the present invention is referred to. Is obtained.

The convex protrusions arranged on the pattern roll used in the ultrasonic fusing machine may be arranged in a single row or a plurality of rows, and when the arrangement is a plurality of rows,
Either parallel or staggered arrangement may be used. When obtaining the spot-shaped fused area, air pressure is applied to the horn to apply pressure. The linear pressure between the horn and the pattern roll is usually 1 to 1
About 0 kg / cm is preferable. If the linear pressure is less than 1 kg / cm, the pressing pressure for obtaining the spot-shaped fused area will be insufficient,
There is a tendency that the cotton fibers are not sufficiently embedded in the fused portion of the ultrafine fibers, and the peel strength does not improve. vice versa,
When the linear pressure exceeds 10 kg / cm, the polypropylene ultrafine fibers flow into the non-fusion area (the portion corresponding to the concave portion of the pattern roll) in the spot-shaped fusion area, and the ultrafine fiber nonwoven fabric is perforated. There is a fear.

[0035]

EXAMPLES Next, the present invention will be described more specifically based on examples. Each characteristic value or physical property value in the examples is measured by the following method. [Melting point of polypropylene-based polymer]: The melting point was the temperature at which the maximum value of the melting endothermic peak was measured with a DSC-2 type differential scanning calorimeter manufactured by Perkin Elmer Co., Ltd. at a temperature rising rate of 20 ° C / min. [Tensile strength of laminated nonwoven fabric]: A value obtained by measuring the maximum tensile strength of a test piece having a width of 5 cm and a length of 10 cm according to the strip method described in JIS L-1096 and converting it into a basis weight of 100 g / m ² . [Tensile elongation of laminated nonwoven fabric]: Elongation at the time of cutting when measuring tensile strength. [Delamination strength of laminated nonwoven fabric]: width 5 cm, length 10 c
Using a constant speed extension type tensile tester in the longitudinal direction of the laminated nonwoven fabric, the test piece of m is sandwiched between the ends of the cotton fiber nonwoven fabric and the ultrafine fiber nonwoven fabric by the chuck of the same tester and peeled at a pulling speed of 10 cm / min. It is the average value of the load values when the test was performed.
The delamination strength in Comparative Example 1 is measured by the same method with the ends of the cotton fiber nonwoven fabric and the long fiber nonwoven fabric being sandwiched. [Bending flexibility of laminated nonwoven fabric]: A test piece having a width of 5 cm and a length of 10 cm was bent in the longitudinal direction, and both ends were joined to form a cylindrical material, which was used as a bending resistance measurement sample. It is the average value of the maximum load values obtained by compressing the sample in the axial direction using a constant-speed extension type tensile tester at a compression rate of 5 cm / min. [Air permeability of laminated nonwoven fabric]: Measured according to the Frazier method described in JIS L-1096. [Water Absorption of Laminated Nonwoven Fabric]: Measured according to the Bayrec method described in JIS L-1096.

Example 1 Using a polypropylene polymer having a melting point of 160 ° C. and an MFR of 70 g / 10 min, a long fiber nonwoven fabric in which polypropylene long fibers were accumulated was produced by a spunbond method. That is,
Polypropylene polymer is melted at 250 ℃ in a spinning machine,
Single hole discharge rate 1.2g / through a spinning hole with a hole diameter of 0.3mm
Extruded in minutes. After cooling the spun long filaments, it is drawn with air sucker at a speed of 4200 m / min, opened with a corona discharge opener, and collected on a moving collection surface.
A web was deposited to give a web, which was pseudo-pressed with a hot embossing roller to obtain a long-fiber nonwoven fabric having a basis weight of 20 g / m ² . The concavo-convex roller of the heat embossing roller has a point pattern, and the area occupied by the pattern is 5 with respect to the roller surface.
%, The surface temperature of the roller was 80 ° C. Further, the fineness of the long fibers constituting the long fiber non-woven fabric is 2.6.
It was denier. The long-fiber nonwoven fabric was prepared as described above.

Next, the melting point is 160 ° C. and the MFR is 400 g.
A polypropylene polymer of / 10 minutes was prepared, and an ultrafine fiber nonwoven fabric made of polypropylene ultrafine fibers was prepared by the following method. That is, the polypropylene polymer is used in the spinning machine 2
It was melted at 80 ° C., and melt-discharged through a spinning hole having a hole diameter of 0.15 mm under the condition of a single hole discharge rate of 0.1 g / min. Then, the discharged molten polymer stream is heated to 300 ° C. with a high-pressure air stream at a flow rate of 170 m / sec for 30 times in the spinning direction.
Angled in the direction of degrees, towed and thinned, collected and accumulated on a suction drum arranged 10 cm below the spinneret, with an average fineness of 0.06 denier and a basis weight of 20 g / m. ^An ultrafine fiber non-woven fabric comprising the polypropylene ultrafine fiber ² was obtained.

Next, a woven cotton fiber having an average fineness of 1.5 denier and an average fiber length of 25 mm was used to prepare a cotton fiber nonwoven fabric in which the cotton fibers were three-dimensionally entangled with each other as follows. That is, a bleached cotton fiber is applied to a random card machine to create a random card web having a random cotton fiber arrangement and a basis weight of 30 g / m ² , and the web is moved at a speed of 20 m / min.
It was placed on a 0 mesh screen. Then, a high-pressure liquid stream (high-pressure water stream) treatment was performed to perform an entanglement treatment. This high pressure liquid flow treatment was performed in two stages. In the first stage treatment, the water jet pressure was 30 kg / cm ² G, and the distance between the web and the jet hole was 5 cm. In the second-stage treatment, the water jet pressure was 70 kg / cm ² G, and the distance between the web and the jet hole was 5 cm. In the second-stage treatment, the water stream was applied twice from both sides of the web. Then, excess water was squeezed with a mangle roll and treated with a drying / heat treatment apparatus kept in an atmosphere of 98 ° C. to obtain a cotton fiber nonwoven fabric.

Next, a laminate obtained by laminating the long fiber non-woven fabric as the upper layer, the ultrafine fiber non-woven fabric as the middle layer and the cotton fiber non-woven fabric as the lower layer was introduced into an ultrasonic fusion machine having the following specifications to obtain a laminated non-woven fabric. . That is, this ultrasonic fusing machine is composed of an ultrasonic oscillator having a frequency of 19.15 KHZ and a pattern roll in which point-like convex projections are arranged on the circumference at an area ratio of 10%. The processing speed was 20 m / min and the linear pressure was 2.5 kg / cm. The laminated nonwoven fabric thus obtained had a basis weight of 70 g / m ² and its physical properties were as shown in Table 1.

Example 2 A laminated nonwoven fabric was obtained in the same manner as in Example 1 except that the area ratio of the convex protrusions on the pattern roll was 30%. This laminated nonwoven fabric had a basis weight of 70 g / m ² and its physical properties were as shown in Table 1.

Example 3 A laminated nonwoven fabric was obtained in the same manner as in Example 1 except that the basis weight of the ultrafine fiber nonwoven fabric was 50 g / m ² . This laminated nonwoven fabric had a basis weight of 100 g / m ² and its physical properties were as shown in Table 1.

Comparative Example 1 A laminated nonwoven fabric was obtained in the same manner as in Example 1 except that the ultrafine fiber nonwoven fabric used in Example 1 was used as the upper layer and the long fiber nonwoven fabric was used as the middle layer. The physical properties of this laminated nonwoven fabric are as shown in Table 1.

Comparative Example 2 A laminated nonwoven fabric was obtained under the same conditions as in Example 1 except that the hot embossing device under the following conditions was used instead of the ultrasonic fusion machine. The heat embossing device has point-shaped convex projections on the circumference at an area ratio of 10%, and is composed of a heat embossing roll heated to 135 ° C. and a room temperature smoothing roll. 50kg linear pressure between roll and smooth roll
/ Cm, and the laminate was introduced between both rolls. The resulting laminated nonwoven fabric has a basis weight of 70 g / m ² ,
The physical properties of this laminated nonwoven fabric are as shown in Table 1.

[0044]

[Table 1]

As is clear from the results shown in Table 1, Example 1
The laminated non-woven fabrics obtained by the methods of Nos. 3 to 3 had high delamination strength between the cotton fiber non-woven fabric and the ultrafine fiber non-woven fabric. On the other hand, the laminated nonwoven fabric obtained by the method according to Comparative Example 1 is an interlayer between a cotton fiber nonwoven fabric and a long fiber nonwoven fabric (in Comparative Example 1, the cotton fiber nonwoven fabric and the long fiber nonwoven fabric are directly bonded). The peel strength was inferior.
This is because long fibers have a higher degree of crystallinity than ultrafine fibers, so when introduced into an ultrasonic fusion machine under the same conditions, the melted long fibers did not show a good flow state, and as a result, they melted. This is probably because the cotton fibers were not sufficiently embedded in the polypropylene filaments. The laminated nonwoven fabric obtained by the method according to Comparative Example 2 was also inferior in delamination strength between the cotton fiber nonwoven fabric and the ultrafine fiber nonwoven fabric. This is because the ultrasonic fusing machine is used in Examples 1 to 3 and the heat embossing device is used in Comparative Example 2. That is, in the hot embossing device, as in the case of using an ultrasonic fusion machine, the melted ultrafine fibers do not show good fluidity, and the cotton fibers are not sufficiently embedded in the melted portion of the ultrafine fibers. Conceivable.

[0046]

The laminated non-woven fabric according to the present invention described above is formed by laminating a long-fiber non-woven fabric, an ultrafine-fiber non-woven fabric, and a cotton-fiber non-woven fabric in this order. Since the cotton fiber nonwoven fabric is entangled with each other, the cotton fibers are excellent in mechanical properties such as tensile strength and fluff prevention property, and exhibit good water absorption by the cotton fibers. Extra fine fiber nonwoven fabric
Since the ultrafine fibers having a fineness of 0.2 denier or less are accumulated, the gap between the ultrafine fibers is small and fine dust can be removed, thereby exhibiting good filter performance. The long fiber nonwoven fabric laminated on one surface of the ultrafine fiber nonwoven fabric is formed by accumulating long fibers having a fineness of 2 to 10 denier, and suppresses fluffing of the ultrafine fiber nonwoven fabric. Also, in contrast to cotton fiber nonwovens,
It exhibits good hydrophobicity.

This laminated non-woven fabric has a point-like fused area in which cotton fibers are embedded in the melting portion of the ultra-fine fibers. The point-like fused area separates the ultra-fine fiber nonwoven fabric and the long-fiber non-woven fabric. It is joined. On the other hand, the ultrafine fiber non-woven fabric and the long fiber non-woven fabric are such that the ultrafine fibers and the long fibers are melted and fused and integrated in this point-like fused area, and the two non-woven fabrics are joined. Therefore, the laminated non-woven fabric in which these three types of non-woven fabrics are joined is partially joined, and the entire surface is not joined, and thus shows good flexibility. Further, in this point-shaped fused area, the fused portion of the ultrafine fiber is shaped to grip the cotton fiber, and the fused portion is fused and integrated with the fused portion of the long fiber to be reinforced. Therefore, even if the laminated non-woven fabric is bent or wound, the melted portion of the ultrafine fiber is less likely to be damaged or destroyed, and the cotton fiber is firmly bonded at this durable melted portion. Achieves high peel strength with fibrous nonwoven fabric. The polypropylene-based ultrafine fiber and the cotton fiber do not have good wettability with each other, and even if the polypropylene-based ultrafine fiber is softened or melted and the two fibers are bonded due to their adhesiveness, strong adhesion cannot be expected. On the other hand, as in the present invention, when cotton fibers are bonded in a state of being embedded in the melted portion of the ultrafine fibers, strong bonding (adhesion) can be expected.

The method for producing a laminated non-woven fabric according to the present invention is a point-like fusion method in which a long-fiber non-woven fabric, an ultrafine-fiber non-woven fabric, and a cotton-fiber non-woven fabric are sequentially laminated into an ultrasonic fusion machine. It is to form an area. This ultrasonic fusion machine is one in which by transmitting vibration of ultrasonic waves to long fibers and ultrafine fibers, frictional heat between long fibers and ultrafine fibers causes the long fibers and ultrafine fibers to melt. is there. Therefore, when the cotton fibers are pressed with a slight pressing force when the ultrafine fibers are melted and are in a fluidized state, the cotton fibers are embedded in the melted portion of the ultrafine fibers. Further, if the melted long fibers are pressed down, the melted portion of the ultrafine fibers and the melted portion of the long fibers are fused and integrated. At this time, the cotton fibers may be embedded in the melting portion of the long fibers through the melting portion of the ultrafine fibers. For example, when a hot embossing device is used to form the spot-shaped fused regions, it is difficult to achieve such a good embedded state of the cotton fibers. This is because the heat embossing device generally melts the ultrafine fibers by heat and pressure, and it is difficult to melt the ultrafine fibers by heat alone like an ultrasonic fusion machine. That is, at the pressure used in the ultrasonic fusion machine,
This is because in the case of a heat embossing device, it is difficult to melt the ultrafine fibers into a state having good fluidity. Also, when a high pressure is applied to the heat embossing device, the melted ultrafine fibers are not melted at this high pressure. This is because the cotton fibers cannot flow into the embossed part and the cotton fiber cannot be embedded.

The fact that a good embedding state as in the present invention can be realized is remarkable when a nonwoven fabric obtained by the melt blown method is used as the ultrafine fiber nonwoven fabric. The melt blown method does not have a process for sufficiently drawing cooled fibers. Therefore, the ultrafine fibers obtained by this method have a low degree of orientation and a low degree of crystallinity. That is, the orientation degree and the crystallinity are lower than those of the fibers obtained by the method such as the spunbond method in which the step of sufficiently stretching the cooled fibers is present. As described above, the fiber with low crystallinity is more likely to be melted at high temperature than the fiber with high crystallinity. Therefore, if the ultrafine fiber non-woven fabric obtained by the melt blown method in the present invention is used, the ultrafine fibers are easily melted by an ultrasonic fusion machine or the like, exhibiting a good flow state, and the cotton fibers are embedded therein. Is done.

[0050]

EFFECT OF THE INVENTION The laminated non-woven fabric according to the present invention has a cotton fiber non-woven fabric disposed on one side having good water absorption, high tensile strength and good anti-fluffing property, and a polypropylene-based extra fine fabric disposed in the middle layer. The fibrous non-woven fabric has good filter performance, and the long-fiber non-woven fabric disposed on the other surface has good hydrophobicity, high tensile strength and good anti-fluffing property. The cotton fiber non-woven fabric and the ultrafine fiber non-woven fabric are bonded in the spot-shaped fusion bonded area and are not bonded over the entire surface, so that the flexibility of the laminated non-woven fabric is not significantly reduced. Also, in this point fusion area,
Both fibers are bonded in a state where the cotton fibers are embedded in the melting portion of the ultrafine fibers, and the melting portion of the ultrafine fibers is fused and integrated with the melting portion of the long fibers to be reinforced. Therefore, even during handling of the laminated nonwoven fabric, the melted portion of the ultrafine fibers is less likely to be damaged or destroyed, and has a high peel strength before and during use of the laminated nonwoven fabric. The laminated non-woven fabric according to the present invention has both excellent water absorption and hydrophobicity, and has various excellent properties and physical properties such that there is little decrease in delamination strength even during handling. Material, clothing, life related materials,
It can be widely used for various purposes such as industrial materials.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a laminated nonwoven fabric according to an example of the present invention.

FIG. 2 is a diagram microscopically showing the dot-like fused regions of the laminated nonwoven fabric according to an example of the present invention in the thickness direction. 1 Cotton fiber 2 Ultrafine fiber fusion zone 3 Point fusion area 4 Long fiber fusion zone

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location D04H 3/00 D04H 3/00 DH

Claims (2)

[Claims] 1. A long-fiber nonwoven fabric in which polypropylene-based long fibers having a fineness of 2 to 10 denier are accumulated, an ultrafine fiber nonwoven fabric in which polypropylene-based fine fibers having a fineness of 0.2 denier or less are accumulated, and cotton fibers are entangled with each other. A laminated non-woven fabric obtained by laminating cotton fiber non-woven fabrics in this order, wherein the laminated non-woven fabric has point-like fused regions provided at intervals, and the long fibers are provided in the point-like fused regions. The non-woven fabric and the ultra-fine fiber non-woven fabric are joined by fusion-bonding the fusion part of the polypropylene-based long fiber and the fusion part of the polypropylene-based ultra-fine fiber, and the ultra-fine fiber non-woven fabric and the cotton fiber non-woven fabric. Is a laminated non-woven fabric, characterized in that at least the polypropylene-based ultrafine fibers are joined by embedding the cotton fibers in the melted portion. 2. A long-fiber non-woven fabric in which polypropylene-based long fibers having a fineness of 2 to 10 denier are accumulated, an ultra-fine fibrous nonwoven fabric in which ultra-fine polypropylene-based fibers having a fineness of 0.2 denier or less are accumulated, and cotton fibers are entangled with each other. The resulting laminated product of cotton fiber non-woven fabric is introduced into an ultrasonic fusing machine, and the polypropylene long fibers and the polypropylene ultrafine fibers are melted and fused at a predetermined point area. A method for producing a laminated non-woven fabric, which comprises integrating and at least embedding the cotton fiber in the melted polypropylene ultrafine fiber.