JPH0841762A - Laminated nonwoven fabric and production of the same - Google Patents

Abstract

PURPOSE:To produce a laminated nonwoven fabric high in interlaminar separation-resistant strength and having good water absorptivity, high tensile strength, good fuzz-preventing property, filter performance capable of removing fine dust, and good flexibility. CONSTITUTION:Cotton nonwoven fabrics are laminated to both the surfaces of an ultrafine fiber nonwoven fabric. The ultrafine fiber nonwoven fabric comprises polypropylene ultrafine fibers each having a fineness of 0.2 denier. In the cotton fiber nonwoven fabric, the cotton fibers 1 are interlaced with each other in a three-dimensional state. The ultrafine fiber nonwoven fabric and the cotton fiber nonwoven fabrics have spot-like fused regions in which the ultrafine fiber nonwoven fabric are directly bound to the cotton fiber nonwoven fabrics. In the spot-like fused regions, the cotton fibers 1 are embedded in the fused part 2 of the ultrafine fibers to bind both the fibers to each other. The laminated nonwoven fabric can be produced by laminating the cotton fiber nonwoven fabrics to both the surfaces of the ultrafine fiber nonwoven fabric and subsequently feeding the laminated product into an ultrasonic fusing machine. The ultrafine fiber nonwoven fabric is melted by the action of the ultrasonic waves to embed the cotton fibers in its melted part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated non-woven fabric obtained by laminating a cotton fiber non-woven fabric and a polypropylene ultra-fine fibrous non-woven fabric, and particularly has a high delamination strength between the cotton fiber non-woven fabric and the polypropylene ultra-fine fibrous non-woven fabric. The present invention relates to a laminated non-woven fabric that is not easily delaminated. The present invention also relates to a laminated nonwoven fabric excellent in tensile strength, flexibility, fluff prevention, filter characteristics and water absorption.

[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 dots) (Japanese Patent Publication No. 54-24506). However, in order to apply the adhesive partially and regularly,
It required complicated work. 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. Requires complicated work,
It 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 is intended to increase the delamination strength of a laminated nonwoven fabric composed of a natural fiber nonwoven fabric and a thermoplastic fiber nonwoven fabric.

[0006]

[Means for Solving the Problems] That is, the present invention has a fineness of 0.
A laminated non-woven fabric obtained by laminating a cotton fiber non-woven fabric in which cotton fibers are three-dimensionally entangled with each other on both sides of an ultra-fine fibrous non-woven fabric made of polypropylene-based ultra-fine fibers of 2 denier or less, wherein the laminated non-woven fabric is An ultrafine fiber nonwoven fabric and the cotton fiber nonwoven fabric have a point-like fused area formed by directly joining, and in the point-like fused area, both fibers are embedded in the fusion part of the ultrafine fiber. The present invention relates to a laminated nonwoven fabric characterized by being bonded and a method for producing the same.

First, the ultrafine fiber nonwoven fabric used in the present invention will be described. This ultrafine fiber nonwoven fabric is made of ultrafine fibers having a fineness of 0.2 denier or less. The ultrafine fibers are made of polypropylene polymer. Polypropylene is generally used as the polypropylene polymer. 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 ultrafine fibers is 0.2 denier or less. The fineness referred to here is the average fineness, and means the average value of the fineness of each ultrafine fiber present in a unit area.
If this fineness exceeds 0.2 denier, the texture of the ultrafine fiber nonwoven fabric itself becomes hard, and it becomes impossible to obtain a laminated nonwoven fabric with high flexibility. In addition, the pore size on the surface of the ultrafine fiber nonwoven fabric becomes large, and the filter performance (performance capable of removing fine dust) deteriorates, which is not preferable.

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.

Next, 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 molten polypropylene-based polymer flow discharged is kept at a temperature 20 to 50 ° C higher than the melting temperature.
It is drawn and thinned by a high-pressure heated gas stream (for example, a high-pressure heated air stream) ejected from a slit-shaped die of about 0.1 to 0.5 mm. Then, the polypropylene-based ultrafine fibers that have been discharged and thinned in this way (at this time, the fineness is 0.2 denier or less) are collected and deposited on the moving collection surface, so that the fineness is 0.2 It is possible to obtain an ultrafine fiber non-woven fabric composed of polypropylene ultrafine fibers having a denier or less.

In the melt blown method, when a polypropylene polymer is melted by a known spinning machine, its melt flow rate value (hereinafter referred to as "MFR") is 100.
It is preferably about 800 g / 10 minutes. MFR is 100g
If it is less than / 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 MFR, but generally 250 to 3
It is about 20 ℃. Moreover, the flow rate of the high pressure heated gas flow is 80 to 30.
About 0 m / sec is preferable, and the jetting direction is preferably 15 to 45 degrees with respect to the spinning line direction.

The basis weight of the ultrafine fiber nonwoven fabric is 10 to 120 g / m ^2.
It is preferably about 10 to 100 g / m ² , 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 forming the nonwoven fabric is low, and the formation of the ultrafine fiber nonwoven fabric itself and May impair filter performance. On the contrary, if the basis weight exceeds 120 g / m ² ,
Although the filter performance is improved, since the thickness becomes too large, the flexibility of the ultrafine fiber nonwoven fabric tends to decrease,
As a result, the flexibility of the laminated nonwoven fabric also 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, the polypropylene-based ultrafine fibers may be simply used as they are. Further, in order to improve the shape retention property or to suppress the fluffing of the surface, a calender roll having a smooth surface may be used for thermal calendering. Instead of the calender roll having a smooth surface, the surface has irregularities. Heat embossing may be performed using an embossing roll.

Next, a cotton fiber non-woven fabric in which cotton fibers are three-dimensionally 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 anti-wool is used as the cotton fiber, a rag machine, a knot breaker, a garnet machine, a slicing machine or the like can be used as an anti-wool machine that can be effectively 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.

The defibration rate by the fluffing machine is preferably in the range of 30 to 95%. If this defibration rate is less than 30%,
Since there are many undisentangled fibers (filaments) in the web, the cotton fiber nonwoven fabric surface may be rough. Further, when a large number of undisentangled fibers are present in the web, when the cotton fibers are three-dimensionally entangled with each other by the high-pressure liquid flow, the high-pressure liquid flow is less likely to penetrate through the undisentangled fibers, resulting in three-dimensional entanglement. There is a tendency to not progress sufficiently. On the other hand, if the defibration rate exceeds 95%, there is almost no undefibrated fibers in the web, and as a result, 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, it is possible to obtain a cotton fiber nonwoven fabric in which cotton fibers are entangled three-dimensionally. Various webs can be used 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, the longitudinal / lateral tensile strength ratio is 1/1.
It is preferable to adopt a web (a cross-laid card web or a random web) such that

The reason why the web is subjected to the high pressure liquid flow treatment is to three-dimensionally entangle the cotton fibers constituting the web. The high pressure liquid flow treatment is generally performed under the following conditions. That is, the pore size is 0.05 to 1.5 mm, especially
The injection pressure is 5 to 150 kg, with an example of 0.1 to 0.4 mm injection holes with a hole interval of 0.05 to 5 mm or multiple devices arranged in multiple rows.
/ Cm ² G of high-pressure liquid is injected from the injection holes, and the web of high-pressure liquid is made to collide with the web placed on the porous support member, whereby the three-dimensional entanglement between the cotton fibers is performed. The injection holes are preferably arranged in a row in a direction orthogonal to the direction of travel of the web. As the high-pressure liquid, water at normal temperature or hot water is generally used. The distance between the injection hole and the web is preferably 1 to 15 cm. If this distance is less than 1 cm, high pressure liquid flow may disturb the formation of the web. On the other hand, this distance
If it 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 three-dimensional entanglement.

The treatment with the high-pressure liquid stream is preferably performed in at least two stages. That is, as the first-stage treatment, the injection pressure of the high-pressure liquid stream is set to 5 to 40 kg / cm ² G, the web is subjected to the high-pressure liquid stream treatment, and the cotton fibers are preliminarily three-dimensionally entangled. 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 preliminarily three-dimensionally entangle cotton fibers in the web, and the second stage treatment can be endured. It becomes difficult to obtain a product having morphological stability. On the contrary, when the injection pressure of the high-pressure liquid flow exceeds 40 kg / cm ² G, the movement of the cotton fibers in the web becomes vigorous, and the texture of the web is disturbed.
Alternatively, the web may have a non-uniform weight. As the second stage treatment, the injection pressure of the high-pressure liquid flow is 50 ■ 150 kg / cm ² G
Then, the web which has been preliminarily three-dimensionally entangled and morphologically stabilized is subjected to a high-pressure liquid flow treatment, and is subjected to sufficient three-dimensional entanglement 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 / cm ² G
If it is less than 3, it becomes difficult to perform sufficient three-dimensional entanglement between the cotton fibers. Conversely, the injection pressure of the high-pressure liquid flow is 150k
If it exceeds g / cm ² G, the three-dimensional entanglement becomes excessive and the densification proceeds too much, tending to reduce the flexibility and bulkiness of the resulting cotton fiber nonwoven fabric. 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 applying the processing 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 mesh screen made of synthetic resin, a perforated plate and the like are 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 wire mesh or mesh screen, the hole diameter is
It is preferably 20 to 200 mesh. If the pore size is less than 20 mesh, the pores are too large and the high pressure liquid flow through the web is discharged directly to the lower side without colliding with the porous support member. There is a risk that it will fall off the sex support member. vice versa,
When 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.

When the web is subjected to the high-pressure liquid flow treatment, the web is impregnated with the liquid. Therefore, 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 three-dimensional entanglement between the cotton fibers in the cotton fiber nonwoven fabric is to increase the tensile strength of the cotton fiber nonwoven fabric and to suppress fuzzing.

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

The laminated non-woven fabric according to the present invention is obtained by laminating this cotton fiber non-woven fabric on both sides of the above-mentioned ultrafine fibrous non-woven fabric. The cotton fiber non-woven fabrics laminated on both sides may be the same one or different ones having different basis weight, thickness, degree of three-dimensional entanglement and the like. On the surface of the cotton fiber non-woven fabric (the surface opposite to the surface contacting the ultra-fine fiber non-woven fabric), other non-woven fabrics, knitted fabrics,
Sheets such as films and meshes may be laminated. The ultrafine fiber non-woven fabric and the two cotton fiber non-woven fabrics are laminated (directly laminated) so as to be directly joined to each other, and are firmly joined (bonded) in the dot-shaped fusion zone 3 shown in FIG. Then, as shown in FIG. 2, the cotton fibers 1 are embedded in the melting portion 2 of the ultrafine fibers in the spot-shaped fusion-bonded area 3 and the cotton fibers 1 and the ultrafine fibers are bonded to each other. is there.

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. Further, 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. If the total area of the dot-like fused areas is less than 4%, the area where the cotton fiber nonwoven fabric and the ultrafine fiber nonwoven fabric are strongly bonded is reduced as a whole, and the delamination strength tends to decrease. 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, it is most preferable to use an ultrasonic welding machine in order to obtain the spot-shaped fusion zone in which the cotton fibers are embedded in the fusion portion of the ultrafine fibers. 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. Because, as described above, the polypropylene-based ultrafine fiber and the cotton fiber are not so good in wettability between them and can be obtained by the present invention even if the heat embossing device is used at high temperature and high linear pressure. Such a strong bond cannot be obtained. 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 (one in which a cotton fiber nonwoven fabric is laminated on both sides of an ultrafine fiber nonwoven fabric) between the ultrasonic oscillator and the pattern roll, the spot-like fused area referred to in the present invention can be obtained. is there. 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. The convex protrusions arranged on the pattern roll used in the ultrasonic fusion machine may be arranged in a single row or a plurality of rows, and when the arrangement is a plurality of rows, they may be arranged in parallel or in a staggered manner. It can be any array of types. 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 1-10kg
/ Cm is preferable. If the linear pressure is less than 1 kg / cm, the pushing pressure for obtaining the spot-shaped fused area will be insufficient, and the cotton fibers will not be sufficiently embedded in the fused portion of the ultrafine fibers, and the peel strength will not be improved. A tendency arises. Conversely, the linear pressure is 10 kg /
If it exceeds cm, the polypropylene-based ultrafine fibers may flow to the non-fusion area (the portion corresponding to the concave portion of the pattern roll) in the spot-shaped fused area, and perforation may occur in the ultrafine fiber nonwoven fabric.

[0026]

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]: Using DSC-2 type differential scanning calorimeter manufactured by Perkin Elmer Co., Ltd., temperature rising rate
The temperature that gives the maximum value of the melting endothermic peak measured at 20 ° C / min was taken as the melting point. [Tensile strength of laminated non-woven fabric]: The maximum tensile strength is measured from 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 is a value converted 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 non-woven fabric]: A test piece with a width of 5 cm and a length of 10 cm is applied to the longitudinal direction of the laminated non-woven fabric using a constant-speed elongation type tensile tester to test the ends of the cotton fiber non-woven fabric and the ultrafine fiber non-woven fabric. Each chuck is clamped and the pulling speed is 10 cm
It is the average value of the load values when peeling at a speed of 1 / min. [Bending flexibility of laminated non-woven fabric]: A test piece having a width of 5 cm and a length of 10 cm was bent in the vertical direction, and both ends were joined to form a cylindrical body, which was used as a bending resistance measurement sample. In the lateral direction of the sample, it was compressed at a compression speed of 5 cm / min using a constant-speed extension type tensile tester,
It is an average value of the obtained maximum load values. [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 BYREC method described in JIS L-1096.

Example 1 A woven cotton fiber nonwoven fabric having an average fineness of 1.5 denier and an average fiber length of 25 mm was used, and a cotton fiber nonwoven fabric in which cotton fibers were entangled three-dimensionally was prepared as follows.
That is, the exposed cotton fiber is put on a random card machine,
Create a random card web with randomly arranged cotton fibers and a basis weight of 25 g / m ² , and apply this web at a speed of 20.
It was placed on a 70 mesh screen moving at m / min. 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 three stages. In the first stage treatment, the water jet pressure is 30kg / cm
² G, and the distance between the web and the injection 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 third step, the conditions were the same as in the second step, and the surface opposite to the web surface applied in the second step was treated. 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 nonwoven fabric.

On the other hand, a polypropylene polymer having a melting point of 160 ° C. and an MFR of 400 g / 10 min was prepared, and an ultrafine fiber nonwoven fabric made of polypropylene ultrafine fibers was prepared by the following method. That is, polypropylene polymer is melted at 280 ° C. by a spinning machine and a single hole discharge amount of 0.1 g is passed through a spinning hole having a hole diameter of 0.15 mm
Melt discharge was performed under the condition of / min. Then, the discharged molten polymer flow is heated to 300 ° C. and the high-pressure air flow is flowed at a flow rate of 170 m.
Per second, it is jetted in a direction that makes an angle of 30 degrees with the spinning line direction, towed and thinned, collected and accumulated on a suction drum arranged 10 cm below the spinneret, and the average fineness is
An ultrafine fiber nonwoven fabric made of polypropylene ultrafine fibers having a denier of 0.06 and a basis weight of 30 g / m ² was obtained.

Next, a laminate in which cotton fiber nonwoven fabric prepared in advance was laminated on both sides of the ultrafine fiber nonwoven fabric was introduced into an ultrasonic fusion machine having the following specifications to obtain a laminated nonwoven fabric. That is, this ultrasonic fusing machine is composed of an ultrasonic oscillator with 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%. And
The processing speed was 20 m / min and the linear pressure was 2.5 kg / cm. The laminated nonwoven fabric thus obtained has a basis weight of 80 g / m ²
The other properties or physical properties are 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 80 g / m ² and other properties and physical properties 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 non-woven fabric is
The basis weight was 100 g / m ² , and other properties and physical properties were as shown in Table 1.

Comparative Example 1 A polypropylene polymer having a melting point of 160 ° C. and an MFR of 70 g / 10 min was prepared and a long fiber nonwoven fabric made of polypropylene long fibers was obtained by the following method. That is, this polypropylene polymer was melted at 250 ° C. by a spinning machine,
Melt discharge was performed through a 0.3 mm spinning hole at a single hole discharge rate of 1.2 g / min. And after cooling this discharge yarn,
Collected by air soccer at a speed of 4200 m / min,
A long fiber web was prepared by opening the fibers with a corona discharge fiber opener and collecting and depositing them on the moving collecting surface. This long fiber web was introduced between the rolls of the hot embossing device,
A long fiber nonwoven fabric of 30 g / m ² was obtained. The heat embossing device used here has dot-shaped convex projections on the circumference of 5% in area ratio.
And a hot embossing roll heated to 80 ° C.
It consists of a smooth roll at room temperature. The fineness (average fineness) of the polypropylene long fibers collected from the long-fiber nonwoven fabric was 2.6 denier.

The cotton fiber non-woven fabric prepared in Example 1 was laminated on both sides of this long fiber non-woven fabric, and an ultrasonic fusion machine was used under the same conditions as in Example 1 to obtain a laminated non-woven fabric. The weight of this laminated nonwoven fabric was 80 g / m ² , and other properties and physical properties were 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-like convex protrusions on the circumference at an area ratio of 10%, and is composed of a heat embossing roll heated to 135 ° C and a smooth roll at room temperature. The linear pressure between the rolls and the smooth roll was set to 50 kg / cm, and the laminate was introduced between both rolls. The resulting laminated nonwoven fabric had a basis weight of 80 g / m ² , and other properties and physical properties were as shown in Table 1.

[0035]

[Table 1]

As is clear from the results in Table 1, Example 1
The laminated non-woven fabrics obtained in Nos. 3 to 3 had higher peel strength between the cotton fiber non-woven fabric and the ultra-fine fiber non-woven fabric and lower air permeability than the laminated non-woven fabric obtained in Comparative Example 1. . This is because the ultrafine fiber nonwoven fabric is used in Examples 1 to 3 and the long fiber nonwoven fabric obtained by the spunbond method is used in Comparative Example 1. That is, since the long-fiber nonwoven fabric has a higher degree of crystallinity than the ultrafine fibers, it does not show a good flow state by the ultrasonic fusion machine, and as a result, the cotton fibers are sufficiently embedded in the melted polypropylene long fibers. It is thought that it was because there was not. Further, since the long fibers have a larger fineness than the ultrafine fibers, the air permeability of the long fiber non-woven fabric does not become sufficiently low. Further, the laminated nonwoven fabrics obtained in Examples 1 to 3 had higher peel strength than the laminated nonwoven fabric obtained in Comparative Example 2. 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.

[0037]

The laminated nonwoven fabric according to the present invention is formed by laminating a cotton fiber nonwoven fabric in which cotton fibers are three-dimensionally entangled with each other on both sides of an ultrafine fiber nonwoven fabric made of polypropylene-based ultrafine fibers. Since the cotton fiber non-woven fabric is formed by three-dimensionally 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.
Since the ultrafine fiber nonwoven fabric is formed by accumulating ultrafine fibers having a fineness of 0.2 denier or less, it has a small gap between the ultrafine fibers and exhibits excellent filter performance capable of removing fine dust.

The ultrafine fiber non-woven fabric and the cotton fiber non-woven fabric have a point-like fused area in which the cotton fiber is embedded in the fusion portion of the ultra-fine fiber, and these non-woven fabrics are joined by this point-like fused area. ing. Therefore, both non-woven fabrics are partially joined, and the entire surface is not joined, so that they show good flexibility. In addition, in this point fusion area, the fusion portion of the ultrafine fibers is shaped to grip the cotton fiber, and since both fibers are bonded together, it has a strong bond and high peel strength. To be realized. Polypropylene-based ultrafine fibers and cotton fibers do not have good wettability with each other, and by softening or melting the polypropylene-based ultrafine fibers,
Even if they try to bond both fibers due to their tackiness, strong adhesion cannot be expected. On the other hand, as in the present invention,
When the 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 to form a dot-like fusion zone by introducing a laminate obtained by laminating an ultrafine fiber non-woven fabric and a cotton fiber non-woven fabric into an ultrasonic fusion machine. is there. This ultrasonic fusion machine is one in which by transmitting vibration of ultrasonic waves to the ultrafine fibers, the ultrafine fibers are melted by frictional heat between the ultrafine fibers. 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. For example, to form a dotted fusion zone,
When a heat embossing device is adopted, it is difficult to realize such a good embedding state. 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, in the case of the heat embossing device, it is difficult to melt the ultrafine fibers into a state having good fluidity under the pressure used in the ultrasonic fusion machine, and the high pressure is applied to the heat embossing device. When applied to,
This is because the high pressure causes the cotton fibers to flow into the non-embossed portions, and the cotton fibers cannot be embedded.

The fact that a good embedding condition as in the present invention can be realized is remarkable when the 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.

[0041]

EFFECT OF THE INVENTION The laminated non-woven fabric according to the present invention has a cotton fiber non-woven fabric provided on both sides with good water absorption, high tensile strength and good anti-fluffing property, and a polypropylene-based extra fine fabric provided in the middle layer. The fibrous nonwoven fabric has good filter performance. 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. Further, in this point-like fused area, both fibers are bonded in a state where the cotton fibers are embedded in the fused portion of the ultrafine fibers, so that they have high peel strength. Since the laminated non-woven fabric according to the present invention has excellent properties and physical properties as described above, it can be widely used in various applications such as medical / sanitary materials, clothing, daily life related materials, and industrial materials. It is possible.

[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 Extra fine fiber 3 Dot fusion area

Claims (4)

[Claims] 1. A laminated non-woven fabric in which a cotton fiber non-woven fabric in which cotton fibers are three-dimensionally entangled with each other is laminated on both sides of an ultra-fine fiber non-woven fabric composed of polypropylene ultra-fine fibers having a fineness of 0.2 denier or less, The laminated non-woven fabric has a point-like fused area formed by directly joining the ultrafine fiber non-woven fabric and the cotton fiber non-woven fabric, and in the point-like fused area, the cotton fiber is embedded in the fusion part of the ultrafine fiber. A laminated non-woven fabric, characterized in that both fibers are bound together in a pressed state. 2. The laminated nonwoven fabric according to claim 1, wherein the ultrafine fiber nonwoven fabric is obtained by a melt blown method. 3. A cotton fiber nonwoven fabric in which cotton fibers are three-dimensionally 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, and the laminate is ultrasonicated. A method for producing a laminated non-woven fabric, which comprises introducing into a fusion machine to melt the ultrafine fibers in predetermined dot-like areas and embedding the cotton fibers in the melted ultrafine fibers. 4. The method for producing a laminated nonwoven fabric according to claim 3, wherein the ultrafine fiber nonwoven fabric is obtained by a melt blown method.