JPH1121754A - Ultrafine composite fiber nonwoven fabric and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a composite fiber nonwoven fabric comprising two or more kinds of thermoplastic resins by a melt-blowing method, producing the nonwoven fabric in a uniform composite ratio in a constant strength and at a low cost. SOLUTION: This spun melt-blown ultrafine composite fiber nonwoven fabric is obtained by melt-spinning two or more kinds of thermoplastic resins from an identical slit spinneret. This method for producing the nonwoven fabric comprises extruding the thermoplastic resins from a die having a slit 7 having a lip width of 0.1-2.0 mm, simultaneously blowing a heated gas on the extruded filmy melted composite thermoplastic from adjacent slits 8 disposed on both the sides of the slit 7 to thin the filmy composite thermoplastic resin into fiber- like products, and simultaneously collecting the fiber-like products on a moving collection surface disposed in the downstream direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrafine composite fiber nonwoven fabric produced by a slit-spinning melt blow method and a method for producing the same.

[0002]

2. Description of the Related Art Ultrafine fibers are processed into nonwoven fabrics and molded articles, and are widely used in disposable diaper surface agents, dustproof clothing, masks, wiping cloths, filters for precision filtration, battery separators and the like. Examples of the filter for microfiltration include applications such as a filter for a cleaning liquid in an electronic device manufacturing process, an air filter, a pre-filter for water for medical products, and a filter for removing microorganisms from food and drinking water.

[0003] In the production of these ultrafine fiber non-woven fabrics, a thermoplastic resin is melt-spun from a plurality of spinnerets, pulled and thinned by a high-speed air stream to form a fiber stream of ultrafine fibers, and then the fiber stream is formed. The melt blow method of collecting and accumulating to produce a nonwoven fabric is mainly used. Such a melt blow method can directly produce a nonwoven fabric having a very fine fiber diameter which is difficult to obtain by other methods.

[0004] Conventional nonwoven fabrics made of ultrafine fibers of a single resin component using the meltblown nonwoven fabric method have disadvantages in that the structure is maintained mainly by the entanglement of the fibers, so that the strength is low and there is a lot of fuzz. ,
It was unsuitable for disposable diaper surface materials. When heat treatment is performed using a heating roll or the like for the purpose of increasing the strength of such a nonwoven fabric, the fibers are melted and the nonwoven fabric tends to be in the form of a film, and the texture is inferior. In addition, since the conventional filter using a single component ultrafine fiber component has little adhesion between fibers, the filtration accuracy fluctuates due to heat sterilization treatment, high-temperature filtration, or vibration, etc. There were drawbacks such as sufficient.

Therefore, in recent years, a composite ultrafine fiber nonwoven fabric made of two different polymers, particularly polymers having different melting points, has been proposed as one which solves the above problem not only by entanglement of fibers but also by fusion. This ultrafine composite fiber nonwoven fabric uses a spinneret for a high-melting resin and a spinneret for a low-melting resin in combination, and is used by laminating a low-melting ultrafine fiber web and a high-melting ultrafine fiber web obtained with each spinneret. Alternatively, a method of improving the mixing state of the fibers by treating the laminate with a needle punch or the like has been proposed.

As a method for direct production, a composite melt-blow spinning method has been proposed, which is disclosed in Japanese Patent Application Laid-Open No. 60-99057.
JP-A-60-99058 and JP-A-60-99058, conduits for introducing two types of polymers from respective extruders,
Disclosed is a side-by-side melt-blow spinneret and spinning method with a hole for connecting a composite component connected to a conduit, and an air orifice.

Further, in US Pat. No. 3,981,650 and JP-A-5-263307, a low-melting resin and a high-melting resin are fed into a spinneret by respective extruders, and a low-melting resin and a high-melting resin are fed. The resin describes a melt-blowing method in which the resin is discharged from alternately arranged separate spinning holes provided in a single spinneret, and according to this method, two types of fibers having a fiber diameter of 20 μm or less are described. A web made of a mixture of ultrafine fibers has been made.

[0008] The method of laminating ultra-fine fiber non-woven fabrics obtained separately from two kinds of resins is simple but not satisfactory in performance and strength in each application. JP-A-60-99057 and JP-A-60-9
In Japanese Patent No. 9058, since different kinds of polymers flow while maintaining their viscosity variations, fluctuations in the molecular weight of the polymer itself and slight fluctuations in the extrusion temperature cause
If a difference in viscosity occurs between the melted polymers, the flow of the melted polymer will be disturbed inside the die, making it impossible to form a uniform composite mass in the die cavity, thus forming a uniform composite blown fiber Can not do,
Even if the temperature inside the extruder is precisely controlled so that the viscosity of the polymer is kept constant, if a large die is used in consideration of productivity, a polymer with different fluidity will be kept at the same temperature. When flowing through the inside of the die, the residence time inside the die inevitably becomes long, so the viscosity balance is lost due to the fluidity of each, and it is not possible to form a composite blow fiber having a uniform composite ratio, and furthermore, the obtained fiber However, there is a problem that the fineness unevenness increases.

The composite meltblowing method disclosed in US Pat. No. 3,981,650 and Japanese Patent Application Laid-Open No. 5-263307 is complicated and expensive in a spinneret and requires a different polymer to be uniformly supplied to each discharge hole. Is difficult to adjust the melt viscosity of In addition, when the discharge amount per one hole of the polymer orifice is increased in order to increase the production amount per unit space, there is a problem that the fibers gradually become larger, and the generation of balls called shots is promoted. For resins with high resistance and easy to generate shear heat, the molecular structure changes due to crosslinking deterioration during spinning, the melt flow rate changes significantly before and after spinning, making spinning difficult,
There was a problem that uniform spinning was not possible.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to produce a composite ultrafine fiber nonwoven fabric composed of two or more thermoplastic resins by a melt blow method at a uniform composite ratio.
It is to provide a less expensive method while maintaining strength.

[0011]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that two or more types of extruders are used so that two or more types of thermoplastic resins are in a predetermined ratio. Using a wide slit with a specific lip width instead of a plurality of spinning orifices, the film-shaped molten mixed resin is made finer by a high-speed gas at a specific flow rate and simultaneously stretched to capture the mixed fiber flow. By collecting the same, it was found that a uniform ultrafine composite fiber nonwoven fabric composed of ultrafine mixed fibers having a narrow fiber diameter distribution can be easily produced with any combination of resins, and the present invention was completed.

That is, the present invention is a slit-spun meltblown ultrafine composite fiber nonwoven fabric obtained by spinning two or more kinds of thermoplastic resins from the same slit die. Width 0.1 ~
A film is discharged from a die having a 2.0 mm slit into a film, and a heated gas is injected from the slit provided adjacent to both sides of the slit into the discharged film-shaped molten composite thermoplastic resin, thereby forming a film. This method is characterized in that the composite thermoplastic resin is collected in a sheet shape on a moving collection surface provided in a downstream direction while being made into a fibrous shape.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION
Two or more thermoplastic resins are discharged from a spinning slit having a wide slit, and a high-speed gas is blown from both sides of the slit onto a wide plastic film obtained from the wide slit, and the film is decomposed into ultrafine fibers, stretched, and It is a non-woven fabric obtained by collecting these ultra-fine fiber flows, having fine inter-fiber voids composed of ultra-fine fibers, soft texture, no fluff, and high strength of high strength. The three-dimensional network structure fused and fixed due to the difference in the melting point of the ultrafine fibers of two or more different resins has the characteristic that the shape is not easily collapsed. In particular, the ultrafine conjugate fiber nonwoven fabric of the present invention prepared by the slit-spinning melt-blowing method has two or more kinds of ultrafine fibers of a thermoplastic resin mixed uniformly, so that the characteristics and performance can be sufficiently exhibited in each application. Further, it is easy to provide a density gradient in the width direction of the nonwoven fabric only by changing the condition setting such as the mixing ratio of two or more kinds of resins.

In the ultrafine composite fiber nonwoven fabric of the present invention, two or more kinds of thermoplastic resins are extruded from each extruder into a slit die portion and merged, and a die having a slit having a lip width of 0.1 to 2.0 mm is formed. Discharge into a composite resin film,
By injecting a heated high-speed gas from the slit provided adjacent to both sides of the resin discharge slit to the discharged film-like molten composite thermoplastic resin, the film-like composite thermoplastic resin is thinned and stretched into a fibrous shape. It is manufactured by collecting in the form of a sheet on a moving collection surface provided in the downstream direction.

In the present invention, as the slit die for discharging the mixed resin, a generally used sheet die or a flat die T die or a coat hanger die used for film production can be used. Of these, a coat hanger die is preferred. The lip width of the slit die is 0.1 to 2.0 mm, preferably 0.2 to 2.0 mm.
1.5 mm. When the width is less than 0.1 mm, the resin cannot be discharged smoothly, and when the width is more than 2.0 mm, the fiber of the film cannot be reduced, which is not preferable. The width of the heated high-speed gas slit provided adjacent to the slit for discharging the resin depends on the high-speed gas velocity, but may have the same width as the resin slit.

As the thermoplastic resin applicable to the slit-spun melt-blown nonwoven fabric method of the present invention, any thermoplastic resin can be used, but it is necessary to use a combination of two or more resins. The combination is
There are various combinations depending on the use of the obtained nonwoven fabric. For example, there is a combination of a resin having an amorphous form and a softening polymer, or a combination of resins having a melting point difference of 10 ° C. or more. Examples of thermoplastic resins include, for example, polyolefin-based resins, polyamides, polyesters, polyester elastomers, low-melting-point copolymerized polyesters, polyester-ether-based copolymerized elastomers, polyester-lactone-based copolymerized elastomers, polystyrene, thermoplastic polyurethane, polyurethane elastomers And the like. Polyolefin resins, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer,
Ethylene-α-olefin random copolymer, atactic polypropylene, polybutene, and the like. As the α-olefin of the ethylene-α-olefin copolymer, an olefin having 3 to 12 carbon atoms, propylene, butene-1, Pentene-1, hexene-1,4-methyl-
Pentene-1,3-methyl-butene-1, heptene-
1, octene-1, nonene-1, decene-1 and the like.

Specific combinations of two or more resins of the present invention include polyethylene terephthalate and polypropylene, polyethylene and polypropylene, polybutylene terephthalate and polypropylene, polyethylene terephthalate and nylon 6, polypropylene and nylon 6, and polystyrene and polypropylene. is there. Further, different materials may be blended to form one component of the composite fiber. The resin component of each resin in the bicomponent conjugate fiber of the present invention is 1
The amount may be 0 to 90% by weight, preferably 40 to 60% by weight, but even outside the range, it can be used depending on the application.

It is a feature of the present invention that the thermoplastic resin convects in a heated high velocity inert gas stream and the time during which it becomes delicate is relatively short, and therefore, the decomposition of the thermoplastic resin when heated is increased. Is relatively rare. But in general,
The thermoplastic convects into the heated die head for a longer period of time than in a fast inert gas stream, and is degraded by both the residence time in the die head and the temperature at which the thermoplastic is held. However, the slit die of the present invention is characterized in that the residence time of the polymer in the die head is short and polymer decomposition is unlikely to occur.

As the high-speed gas used in the present invention, any inert gas which does not react with the thermoplastic resin is used. However, the high-speed gas stream for thinning the film into fibers or micro fibers is made of air. Is preferred. The flow rate of the high-speed gas must be such that it is necessary to decompose the formed film into ultrafine fibers immediately after leaving the wide slit spinning nozzle and collect these fibers as a nonwoven fabric.
It is necessary to spray from the slit at 1 to 5 kg / cm ² , preferably 1 to 3 kg / cm ² . 0.1kg / cm
^If it is less than ² , the fiber of the film cannot be formed and 5 kg / cm ²
Exceeding this is not preferable because it becomes difficult to collect as a nonwoven fabric. An advantage of the present invention is that these speeds can be increased throughout. Usually, the temperature of the high-speed gas suitable for microfibrillation is preferably higher than the melting point of the high melting point thermoplastic resin.

The finely divided and drawn ultrafine composite fiber stream is collected in a sheet shape on a moving collection surface provided in the downstream direction while the fibers are entangled with each other and fused. By controlling the distance between the collecting surface and the die, the fiber diameter and hole diameter of the nonwoven fabric can be easily changed.

The details will be described below with reference to the drawings. FIG. 1 is a schematic view of the vicinity of a melt blow die slit of the nonwoven fabric manufacturing apparatus of the present invention. The two kinds of thermoplastic resins are introduced into the die cavity 5 through the extruders 1 and 2 and the conduits 3 and 4. In the die cavity 5, the two types of resin are separated into different separate layers and are discharged from the slit 7. Slits 8 for blowing out high-speed gas air are arranged on both sides of the slit 7. This air thins the discharged thermoplastic resin and stretches it into ultrafine fibers. The fibers are entangled in the gas stream and travel to a collector, such as a finely-perforated cylindrical screen or drum, or a working belt, where they are condensed and collected as entangled nonwovens. The nonwoven fabric, which is an aggregate of the ultrafine fibers, is taken out of the collector and wound around a roll.

The apparatus illustrated in FIG. 1 has a single, undivided die cavity into which two different thermoplastics are introduced, but alternatively reaches the exit area of the slit. Immediately before, a separator for separating the thermoplastic resin is provided in the die cavity. By changing the angle of the separator with respect to the resin flow, it is possible to obtain a composite nonwoven fabric having a gradient in the fiber diameter or the like by passing through the slit as a multilayer flow having a concentration gradient of two kinds of resins entering the slit. The viscosity of the thermoplastic resin passing through the slit may be similar to or different from the ordinary melt blow method using a large number of orifices, and may be controlled by controlling the resin composition such as temperature and residence time in the extruder. Can easily be made.

It is considered that, when two kinds of resin are used as A / B, for example, the discharged and thinned ultrafine fibers are formed into ultrafine fibers similar to the side-by-side type, and A / B / A It is considered that when used as such, it becomes an ultrafine fiber similar to the core-sheath structure type. Also, by using three or more types of resins, ultrafine fibers similar to a side-by-side type having three or more layers can be easily obtained.

The drawn fiber preferably has an average of 1
It has a fiber diameter of less than 5 μm, more preferably 1 to 15 μm, but can be easily changed by changing spinning conditions, and also easily by changing the distance between the die and the collector. .

Other fibers and the like may be mixed in the ultrafine composite fiber nonwoven fabric of the present invention. For example, staple fibers, particulate matter, etc. can be introduced into the fiber stream before reaching the collector, and may be combined with the fibers in a subsequent heat treatment, molding operation.

The thickness of the nonwoven fabric of the present invention can vary greatly. For most applications, about 0.05-5c
Those having a thickness of m are used. Depending on the application, two or more nonwoven fabrics separately formed may be used in a stacked manner.
Also, the nonwovens of the present invention may be made by depositing the fiber stream directly onto another sheet material, such as another porous nonwoven. Special structures, such as other films, can be laminated to the sheet nonwoven fabric of the present invention by mechanical entanglement, heat bonding, or adhesives.

The nonwoven fabric of the present invention may be further processed after being collected by a collector. For example, the pore size and thickness of the nonwoven fabric sheet may be controlled by heat treatment and pressure treatment, a pattern may be given to the nonwoven fabric, or particulate matter may be fixed.

The slit spinning meltblowing technique of the present invention is subject to the action of the gas stream over a larger surface area than the polymer stream extruded from the circular outlet of the orifice having the same discharge rate, so that even high viscosity polymers can be used. This can be applied, and the number of shots can be reduced as compared with the case where the circular discharge port of the orifice is used. Furthermore, when a nonwoven fabric made of fine fibers is collected on a flat surface, there is an advantage that the nonwoven fabric can be produced at a significantly higher efficiency because the rate of change in thickness is small.

[0029]

Embodiments of the present invention will be described below in detail. The present invention is not construed as being limited to the following examples. The test method in this example is as follows. (1) basis weight: sample than the length direction, collect specimens of 100 × 100 mm, measuring the weight of the moisture equilibrium, 1 m ²
It was converted to per hit. (2) Thickness: A test piece of 100 × 100 mm was sampled from the sample length direction and measured with a dial thickness gauge (7321 manufactured by Mitoyo Seisakusho, 1 mm / 1 rotation). (3) Average fiber diameter: Five photographs were taken of any five points of the test piece with an electron microscope, the diameter of 20 fibers was measured for each photograph, and these were performed for the five photographs.
The average fiber diameter of 100 fibers was determined. (4) Tensile strength: 50 × 200 mm from the sample length direction
Of JIS L 1096 6.12A
Chuck interval 100mm, tensile speed 300m
The measurement was performed one by one at m / min. (5) Specific gravity: A 25 × 200 mm test piece was sampled from the sample length direction, and the weight in a water equilibrium state was measured.
According to the plastic specific gravity measurement method of D792-66, it was measured from the weight immersed in water and the dry weight based on the principle of Archimedes.

Example 1 The ratio (L / D) of the length and diameter of the screw of the extruder was 25.
2 extruders, 3 inches long as shown in FIG. 1, resin discharge lip width 0.35 mm, air discharge slit width 0.20
mm using a melt spinning slit spinneret.
As components, the melt flow rate (hereinafter, referred to as MFR) is 300 (g / 10 minutes, 230 ° C.), and the melting point is 165.
C. as a second component at an extrusion temperature of 300 ° C. and an adjusted MFR of 100 (g / 10 min, 190
° C), and melt-extrusion of a linear low-density polyethylene having a melting point of 123 ° C at an extrusion temperature of 270 ° C, and melt-blown from a resin discharge slit at a die temperature of 280 ° C to obtain a two-component slit composite meltblown nonwoven fabric. . At this time, the weight ratio of the first component to the second component was 50:50, and the total discharge amount was 100 g / hour / inch. Also,
The temperature of the air used for melt blowing is 300 at the inlet.
° C and pressure were 3.1 kg / cm ² . The resulting polypropylene / polyethylene two-component slit composite meltblown nonwoven fabric has a basis weight of 40.3 g / m ² and a thickness of 0.3.
8 mm, and the average fiber diameter was 8.5 μm. Next, the nonwoven fabric was calendered at a temperature of 125 ° C. to a thickness of 150 μm, and the tensile strength was measured. The result was 2.7 kg / 50 mm in the sample length direction.

Comparative Example 1 Using the apparatus used in Example 1 and the first and second components
The polypropylene of the first component has an extrusion temperature of 300
° C, base temperature 280 ° C, heated air temperature 300 ° C, pressure
3.1 kg / cm^TwoThe linear low density polyethylene of the second component
Len has an extrusion temperature of 270 ° C, a die temperature of 280 ° C, and heating.
Air temperature 290 ° C, pressure 3.1kg / cm ^TwoAnd it
Each is melt blown and the basis weight is 10 g / m.^Twoof
Single-component slit-spun melt bar comprising a first component and a second component
A raw nonwoven fabric was obtained. The average fiber diameter of each nonwoven fabric is
They were 6.5 μm and 9.0 μm. The two types of obtained
Alt blown non-woven fabric alternately laminated into 4 layers, total
40 g / m^TwoAnd calender at a temperature of 125 ° C
After processing to a thickness of 150 μm, measure the tensile strength
It was 1.5 kg / 50 mm in the sample length direction.
Was.

Example 2 Using the apparatus used in Example 1 except that the lip width was changed to 0.3 mm, the polypropylene used in Example 1 was extruded at the extrusion temperature of 300 ° C. as the first component. As
Each of the polybutylene terephthalates having an intrinsic viscosity of 0.84 and a melting point of 224 ° C. was melt-extruded at an extrusion temperature of 290 ° C. and melt-blown from a slit at a die temperature of 310 ° C. to obtain a two-component slit composite melt-blown nonwoven fabric.
At this time, the weight ratio of the first component to the second component is 40: 6.
At 0, the overall output was 100 g / hr / inch. The temperature of the air used for melt blowing was 320 ° C. at the inlet, and the pressure was 3.5 kg / cm ² .
The resulting two-component slit composite meltblown nonwoven fabric is
The basis weight was 63.0 g / m ² , the thickness was 0.46 mm, and the average fiber diameter was 6.8 μm. Next, this non-woven fabric is
At a temperature of 55 ° C., calendering is performed to a thickness of 20
When the tensile strength was measured at 0 μm, it was 4.0 kg / 50 mm in the sample length direction.

Comparative Example 2 Each of the apparatus used in Example 2 and the first and second components was melt-blown and had a basis weight of 15 g.
/ M ² , a single component slit-spun meltblown nonwoven fabric of the first component and the second component. The average fiber diameter of each nonwoven fabric was 7.5 μm and 6.0 μm. The obtained two types of melt-blown nonwoven fabrics are alternately laminated to form four layers,
The total weight was 60 g / m ² , calendering was performed at a temperature of 155 ° C. to a thickness of 150 μm, and the tensile strength was measured. As a result, 2.2 kg / 50 was measured in the sample length direction.
mm.

Embodiment 3 A length of 3 inches and a resin discharge lip width of 0.6 shown in FIG.
MFR as a first component using a melt-blowing slit spinneret having an air discharge slit width of 0.45 mm.
Is 100 (g / 10 min, 190 ° C.), and a linear low-density polyethylene having a melting point of 123 ° C. is extruded into two extruders (2-1) having a screw length to diameter ratio (L / D) of 25. , 2
Extruded at an extrusion temperature of 270 ° C in -2), and as a second component, the adjusted MFR is 90 (g / 10 minutes, 230 ° C);
A polyethylene-propylene copolymer having a melting point of 138 ° C. (polyethylene copolymer content: 3.6% by weight)
The extruder (1) having an / D of 20 extruded at an extrusion temperature of 290 ° C. and melt-blown from the slit at a die temperature of 280 ° C. to obtain a two-component slit composite melt-blown nonwoven fabric.
At this time, the weight ratio of the first component to the second component is 60: 4.
At 0, the overall output was 200 g / hr / inch. The temperature of the air used for melt blowing was 320 ° C. at the inlet, and the pressure was 3.5 kg / cm ² .
The obtained polypropylene / polyethylene two-component slit composite meltblown nonwoven fabric has a basis weight of 62.2 g /
m ² , a thickness of 0.57 mm, and an average fiber diameter of 11.
It was 4 μm. When the cross section of the fiber of the two-component slit composite meltblown nonwoven fabric was observed with a microscope, it was confirmed that the fiber had a core-sheath type composite fiber.

Example 4 The polypropylene used in Example 1 was extruded at the extrusion temperature of 290 ° C. as the first component using the apparatus used in Example 1 except that the lip width was changed to 0.3 mm. As
Nylon 6 having a relative viscosity of 2.30 and a melting point of 220 ° C. was melt-extruded at an extrusion temperature of 290 ° C., and melt-blown from a slit at a die temperature of 290 ° C. to obtain a two-component slit composite melt-blown nonwoven fabric. At this time, the weight ratio of the first component to the second component was 50:50, and the total discharge amount was 100 g / hour / inch. The temperature of the air used for melt blowing was 320 ° C. at the inlet, and the pressure was 3.1 kg / cm ² . The obtained two-component slit composite meltblown nonwoven fabric has a basis weight of 65.0 g / m2.
² , the thickness is 0.44 mm, the average fiber diameter is 8.8μ
m. 2 of the obtained polypropylene / nylon 6
A test piece was cut out from the sample length direction of the component-based slit composite meltblown nonwoven fabric, and the specific gravity of the test piece in the sample length direction was measured at n = 10. The weight blending ratio of polypropylene was from 46.3% by weight to 55.7%. Weight% value is obtained,
The value was almost constant.

COMPARATIVE EXAMPLE 3 A total of 95 spinning holes having a hole diameter of 0.4 mm were arranged in a line.
A two-component composite melt-blown nonwoven fabric of polypropylene / nylon 6 with a basis weight of 60 g / m ² was obtained using the same apparatus as in Example 4, except that the usual spinneret for melt-blowing was used. The average fiber diameter of this nonwoven fabric was 6.3 μm. A test piece was cut out from the sample length direction of the obtained polypropylene / nylon 6 two-component composite melt-blown nonwoven fabric, and the specific gravity of the test piece in the sample length direction was measured at n = 10. A value of from 7% by weight to 73.3% by weight was obtained, showing a large variation, and it was found that the compound of the present invention had a stable blending ratio of the two components.

[0037]

EFFECT OF THE INVENTION The slit-spun melt-blown ultrafine composite fiber nonwoven fabric of the present invention has fibers of two or more kinds of thermoplastic resins mixed uniformly, and is superior in entanglement and the like to a laminate of single resin fiber nonwoven fabric, and has improved strength. Have been. In addition, the composite ultrafine fiber nonwoven fabric of the present invention has a more uniform resin mixing ratio in the fiber length direction than the melt-blown nonwoven fabric using a die having a plurality of orifices, and the strength is maintained.
Can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view near a two-layer resin melt blow die slit.

FIG. 2 is an enlarged cross-sectional view near a three-layer resin melt blow die slit.

[Explanation of symbols]

 1, 2 Extruder 3, 4 Resin conduit 5 Die cavity 6 Gas inlet 7 Slit 8 Gas slit

Claims (3)

[Claims] 1. A slit-spun melt-blown ultrafine composite fiber nonwoven fabric obtained by spinning two or more kinds of thermoplastic resins from the same slit die. 2. A method in which two or more kinds of thermoplastic resins are discharged in the form of a film from a die having a slit having a lip width of 0.1 to 2.0 mm, and the discharged film-like molten composite thermoplastic resin is provided with the slit. By injecting a heating gas from slits provided adjacent to both sides of the film, the film-like composite thermoplastic resin is collected in a sheet shape on a moving collection surface provided in a downstream direction while being thinned into a fiber shape. A method for producing a slit-spun melt-blown ultrafine composite fiber nonwoven fabric, characterized by the above-mentioned. 3. The method for producing a slit-spun melt-blow ultrafine composite fiber nonwoven according to claim ² , wherein a heating gas is injected at 0.1 to 5 kg / cm ² to thin the film-like molten composite thermoplastic resin into fibers. .